Compressed natural gas. Types of gas engine fuel, their advantages and disadvantages

But the 1973 oil crisis renewed interest in gas in the automobile industry.

Characteristics

Performance properties

Methane fuel has a higher octane number and specific heat of combustion than petroleum fuel or liquefied petroleum gases and does not change physical and chemical properties at low temperatures. The octane number of compressed natural gas is in the range of 110-125 and upon combustion produces 48,500 kJ/kg, gasoline - 76-98 and 44,000 kJ/kg, propane-butane - 102-112 and 46,000 kJ/kg. However, CNG is inferior to gasoline and propane-butane in the calorific value of the stoichiometric mixture, and provides 6-8% lower performance in engines designed for 2 types of fuel.

Vehicles using compressed natural gas have lower operating costs. The cost of 100 kilometers of CNG-powered cars, trucks and buses is 1.5-2.5 times lower than that for vehicles powered by gasoline, diesel fuel or LPG. Methane does not form carbon deposits on pistons, valves and spark plugs, does not wash off the oil film from the cylinder walls, does not dilute the oil in the crankcase, due to which the vehicle’s overhaul mileage increases by 1.5 times, the service life of the engine oil, spark plugs and cylinder-piston group - by 1 ,5-2 times. Reducing the load on the engine also reduces its operating noise by 7-9 decibels.

Safety

Equipment for compressed natural gas has a multiple safety margin. The cylinders are tested for destruction when dropped from a height, hit by a firearm, exposed to an open flame, extreme temperatures and aggressive environments, and are also placed in parts of the car that are statistically less susceptible to deformation: according to BMW, the probability of significant damage to these parts of the body is in the range of 1 -5%. According to statistics, the American Gas Association compiled statistics based on the operation of 2,400 gas-fueled vehicles with a total mileage of 280 million km in the 1990s - 2000s. The data showed that in 180 out of 1,360 collisions the impact occurred in the area where the cylinders were located, but none were damaged, and in 5 cases gasoline ignited.

Environmental friendliness

Compressed natural gas is one of the most environmentally friendly types of fuel and complies with the Euro-5/Euro-6 standard. Carbon dioxide emissions when using CNG are 0.1 grams per kilometer. CNG cars emit 2 times less nitrogen oxides, 10 times less carbon monoxide and 3 times less other carbon oxides than cars with gasoline engines. When natural gas is burned, no soot is formed, and there are no emissions of lead or sulfur. In general, the use of CNG provides 9 times less smoke in the ambient air.

Standardization

The quality of CNG is regulated by the following national standards:

• GOST 27577-2000 “Compressed natural fuel gas for internal combustion engines. TU" (RF standard);
• J1616 1994 “Surface vehicle recommended practice - recommended practice for compressed natural gas vehicle fuel” (US standard developed by SAE (Society of Automotive Engineers));
• SAE J1616 (US standard);
• CARB (CNG specification, USA, California);
• DIN 51624 “Automotive fuels Natural Gas - requirements and test procedures” (German standard);
• Legge 14 Novembre 1995 No. 481. “Disposizioni generali in tema di qualita del gas natural” (Italian standard setting standards for network natural gas used for the production of CNG);
• Regulation of the Polish Ministry of Economy on the quality requirements for compressed natural gas (CNG) (Polish standard);
• GB 18047-2000 “Compressed natural gas as vehicle fuel” (Chinese standard);
• SS 15 54 38 "Motor fuels. - Biogas as fuel for high-speed engine engines" (standard for compressed biomethane used as motor fuel (types A and B); developed by the Swedish Institute for Standardization, adopted on September 15, 1999 and is generally recognized in European countries);
• PCD 3 (2370)C “Compressed natural gas (CNG) for automotive purposes. Specification" (Indian standard);
• PNS 2029:2003 “Natural gas for use as a compressed fuel for vehicles - Specification” (Philippine standard);
• 10K/34/DDJM/1993 (decree of Oil and Gas Director General, dated February 1, 1993) (Indonesian standard).

Technologies for processing and use of natural gas, reflected in national standards, are summarized in the international standard ISO 15403 “Natural gas for use as a compressed fuel for vehicles”. Its first part establishes requirements for natural gas indicators that ensure safe and trouble-free operation of gas filling equipment and vehicle equipment, the second part establishes requirements for quantitative values ​​of parameters that standardize the quality of natural gas as a transport fuel.

Usage

Cars

Gas car engines are classified according to the number of types of fuel, the use of which is provided for by the design. Gas (mono-fuel, English dedicated, monovalent) engines are designed directly to run on natural gas, which ensures the greatest efficiency. Generally, gas engine vehicles do not have a gasoline tank, but sometimes support the use of gasoline as a backup fuel. Gasoline-gas (bi-fuel, bi-fuel, bivalent) engines allow the use of both gas and gasoline. Most gasoline-gas vehicles are vehicles converted outside the manufacturer. Gas-diesel (English dual-fuel) engines consume more diesel at low speeds, and more gas at high speeds. Gas and petrol-gas engines are most common in passenger cars and light trucks, while gas-diesel engines are most common in heavy trucks.

Production vehicles running on compressed natural gas are produced by many automobile concerns, including Audi, BMW, Cadillac, Ford, Mercedes-Benz, Chrysler, Honda, Kia, Toyota, Volkswagen. In particular, in the segment of passenger cars and light trucks, the market includes Fiat Doblò 1.4 CNG, Fiat Qubo 1.4 Natural Power, Ford C-Max 2.0 CNG, Mercedes-Benz B 180 NGT, Mercedes-Benz E200 NGT, Mercedes-Benz Sprinter NGT, Opel Combo Tour 1.4 Turbo CNG, Opel Zafira 1.6 CNG Ecoflex, Volkswagen Caddy 2.0 Ecofuel and Life 2.0 Ecofuel, Volkswagen Passat 1.4 TSI Ecofuel, Volkswagen Touran 1.4 TSI Ecofuel, Volkswagen Transporter Caravelle 2.0 Bensin/Gas, Volvo V70 2.5FT Summum and other models. Large freight and passenger vehicles running on CNG are produced by Iveco, Scania, Volvo and other companies. Basic Russian manufacturers gas engine equipment - GAZ Group, KamAZ and Volgabus. In total, about 150 models of gas-cylinder equipment are presented on the Russian market, including KamAZ truck tractors, medium-tonnage GAZon Next CNG, light-tonnage GAZelle Next CNG and GAZelle Business CNG, passenger cars Lada Vesta, Lada Largus, modifications of UAZ Patriot and other .

Governments of many countries are resorting to organizational, regulatory and financial incentive measures to popularize gas fuel. Popular organizational measures include a ban on the use of diesel fuel in vehicles of light and medium-duty or passenger capacity, within cities and environmental zones (Pakistan, Iran, South Korea, Brazil), a ban on the use of petroleum fuels in public and municipal transport (France) ), priority access of gas fuel consuming companies to municipal orders (Iran, Italy). Regulatory measures, mainly affect the design and construction of CNG filling stations and include bans on the construction of gas stations without a natural gas filling unit (Italy) or relaxations for the construction of CNG filling stations within urban areas (Turkey, Austria, South Korea). Financial incentives include one-time payments for the conversion or purchase of new vehicles using CNG (Italy, Germany), subsidized loans for conversion (Pakistan), exemption of car owners from parking fees (Sweden), duty-free import of imported gas equipment (European Union countries, Iran), abandonment of the price link between gas fuel and oil (EU).

Water transport

Compressed natural gas is less common as a fuel for inland and marine shipping than the more convenient liquefied natural gas for transportation and storage, but has applications in dual-fuel propulsion systems. Gas is used as a shipping fuel on tourist ships in the USA (for example, the Elizabeth River I ferry with a capacity of 149 people) and Russia (Moscow and Neva-1), the Netherlands (Mondriaan and Escher, launched in 1994, Rembrandt and Van Gogh - in 2000). Also in 2011, there were 11 CNG barges operating in Amsterdam. In Canada and Norway, CNG is used mixed with diesel fuel in the power plants of seagoing bulk carriers and passenger ferries. Examples of CNG ships include the limestone carrier M.V., launched in Adelaide, Australia in the late 1980s. Accolade II, as well as ferries M.V. Klatawa and M.V. Kulleet, built in 1985, provided transportation of passengers and cars across the Fraser River near Vancouver for 15 years. In 2008, the Singapore-based Jenosh Group launched a container ship whose gas cylinders are loaded into standard 20-foot containers. In 2009-2010, the Chinese shipyard Wuhu Daijang built 12 such ships for operation in Thailand and received an order for 12 more ships, and the Jenosh Group began developing a container ship with a cruising range of 1,500 nautical miles, targeting customers from India, Pakistan, Indonesia and Vietnam.

Aviation

Compressed gas has not become widespread as aviation fuel. In 1988, the Tupolev design bureau took into the air an experimental Tu-155 powered by CNG, which was used to test gas fuel: a smaller mass of gas could provide the aircraft with a larger payload. Compressed gas has potential for small aircraft with relatively low fuel consumption. For example, in 2014, Aviat Aircraft released the two-seat Aviat Husky, the first production dual-fuel aircraft.

Rail transport

Environmental safety and economic feasibility of using compressed natural gas promote its use in other modes of transport, including railways. In 2005, the world's first compressed gas powered train began operating in the central region of Peru. In January 2015, the Indian Railways Minister inaugurated the train, powered by a mixture of diesel and CNG propulsion, on the line between the cities of Rewari and Rohtak in the state of Haryana. Also in January 2015, a gas-powered train entered service on the line between the Czech cities of Opava and Hlučín.

Prevalence

Leading countries in the number of CNG vehicles (left) and by the share of CNG vehicles in the national vehicle fleet (right)
Place	Country	Number cars (thousands)	Place	Country	Share of cars on CNG in the country's vehicle fleet (%)
1	China	5000	1	Armenia	56,19
2	Iran	4000	2	Pakistan	33,04
3	Pakistan	3000	3	Bolivia	29,83
4	India	3045	4	Uzbekistan	22,5
5	Argentina	2295	5	Iran	14,89
6	Brazil	1781	6	Bangladesh	10,53
7	Italy	1001	7	Argentina	9,93
8	Colombia	556	8	Georgia	8,47
9	Thailand	474	9	Colombia	5,58
10	Uzbekistan	450	10	Peru	5,25
Total for 2016 in the world: ~24.5 million CNG vehicles or 1.4% of the total vehicle fleet

The largest macro-region in terms of the number of CNG vehicles is Asia. ~15 of ~24.5 million cars are concentrated there. About 5 million more come from Latin American countries. In Europe, CNG is used in 2 million cars. The countries of Africa and North America account for a total of about 370 thousand more cars.

Africa

Edition NGV Africa in November 2014, it provided data according to which there were about 213 thousand CNG vehicles and 200 gas stations in Africa. The gas vehicle fleet in Africa grew by just 3% between 2012 and 2016. De facto, the only developed market is Egypt, where infrastructure began to be developed in the mid-1990s and where by September 2014 there were almost 208 thousand gas-cylinder vehicles (just under 3% of the country’s total vehicle fleet) and 181 gas stations.

In other countries on the continent - Nigeria, South Africa, Mozambique, Algeria, Tanzania and Tunisia - the introduction of CNG is targeted and mainly affects buses. In Nigeria, in the 2010s, a state program worth $100 million was launched to build a gas filling infrastructure, which should in the future increase the fleet of gas vehicles to several tens of thousands. The spread of CNG in Africa, including Egypt, is hampered by high cost re-equipment of cars and construction of gas stations, as everything necessary equipment imported .

Oceania

The number of CNG vehicles in Oceania is extremely small. In New Zealand, against the backdrop of the oil crises of the 1970s and early 1980s, 120 thousand vehicles, or 11% of the total vehicle fleet, were converted to CNG. With the abolition of government subsidies for the conversion of cars in 1986 and against the backdrop of falling oil prices, the CNG vehicle fleet gradually began to decline, and by 2016 the number of gas cars dropped to 65 units.

North America

Between 2012 and 2016, the gas vehicle fleet in North America grew by 26%. This growth is largely due to the low base effect - in North America There are fewer CNG cars than in Africa - only about 180 thousand cars.

Canada

In Canada, thanks to federal and provincial programs launched in the 1980s to study gas as a fuel and its introduction into road transport, the number of cars running on CNG grew to 35 thousand by the mid-1990s. Gas was widely used as fuel in regular buses. After the fall in oil prices, gas support programs were curtailed. Subsequently, against the backdrop of limited supply from manufacturers of CNG-ready cars and an ever-shrinking infrastructure (from 1997 to 2016, the number of gas stations fell from 134 to 47), the fleet of gas cars decreased to 12 thousand units.

USA

Like Canada, the United States has been implementing programs to replace expensive petroleum fuel with gas since the early 1980s. The number of CNG vehicles peaked in 2004 (121 thousand) and has stopped growing. Only in the 2010s did growth begin, driven both by environmental initiatives in states such as California, as well as by a sharp drop in gas prices as a result of the shale revolution. As of 2016, there were 160 thousand gas vehicles and 1,750 gas stations in the United States. The highest density of gas station networks in 2013 was in Southern California. As of 2016, many private companies and the authorities of a number of states announced plans to build a network of gas stations.

Low gas prices have been followed by demand from commercial companies. American manufacturers Automotive components began to offer new equipment for trucks and buses. CNG school buses were presented by Thomas Built Buses and Freightliner Custom Chassis Corporation. Demand for new developments has been bolstered by the U.S. Department of Transportation, which announced a $211 million grant to repair and upgrade school and bus buses in 41 states. Some of the supported projects involve replacing old diesel buses with new ones running on compressed natural gas. In 2016, transport companies FedEx and United Parcel Service expanded their fleet of gas vehicles and at the same time built their own networks of CNG filling stations.

The spread of CNG on the mass market was hampered by the limited supply of cars. In fact, the only production car adapted for the use of CNG was the Honda Civic. Chrysler's CNG-powered Ram 2500 came out in 2012. For the 2014 model year, Ford introduced the F-150 bi-fuel pickup truck, and in 2015 its bi-fuel competitor, the Chevrolet Silverado, came out.

Latin America

Latin America is the second largest market after Asia. As of 2016, there were about 5.5 million CNG vehicles. The country with the highest penetration of CNG as a vehicle fuel in South America is Bolivia: in 2016, 360 thousand vehicles were driven by CNG, that is, almost only 30% of vehicles. Moreover, this is an indicator for public transport was even higher - 80%. One of the reasons for the high penetration of CNG was that the drivers' confederation achieved funding for a program for converting vehicles to CNG from the state budget from taxes and fees on the sale of natural gas without additional payments from drivers.

According to 2016 data, in terms of the absolute number of CNG vehicles, Bolivia is ahead of Colombia, where there were 543 thousand, as well as Argentina and Brazil with 2.295 million and 1.781 million CNG vehicles, respectively. Widespread CNG in Argentina was promoted by the policy of President Raul Alfonsin, carried out in the 1980s to replace increasingly expensive petroleum fuels. In Brazil, CNG was first used as a fuel for passenger vehicles in 1996, and before that, cars running on bioethanol derived from sugar cane were widespread in the country. Thanks to a number of government programs, the number of vehicles running on CNG reached a million in just 9 years.

Europe

The European gas market is the third largest in the world, behind Asia and Latin America. As of 2016, there were more than 2.187 million gas-powered vehicles in Europe, a number that had grown by 25% over the previous four years. The total number of gas stations reached 4,608.

EU and EFTA

In the European Union, Directive 2014/94/EU of the European Parliament and the European Council on the deployment of alternative fuel infrastructure of October 22, 2014 is in force. The Directive requires EU member states to adopt national framework programs for the development of the market for alternative fuels and establishes standards for the required number of filling stations with alternative fuels based on the size of the population and the distance of filling stations from each other, and provides for the application of common EU standards for filling stations and charging stations electric vehicles, establishes a way to communicate information about alternative fuels to consumers, including a methodology for clear and clear comparisons of fuel prices. The Directive sets the following deadlines for the development of CNG infrastructure in the EU: the creation of sufficient infrastructure in urban and densely populated areas by the end of 2020, the creation of a network of CNG filling stations along the TEN-T corridors (English) Russian by the end of 2025.

Russia

By October 2016, more than 145 thousand cars using CNG were registered in Russia.

Natural gas in Russia is mainly sold at automobile gas filling compressor stations (CNG filling stations), to which gas is supplied directly through gas pipelines. A similar solution was inherited from the Soviet Union, which began a gas transport development program in the 1980s. The program was developed for the future, since the USSR did not experience a shortage of petroleum products. The decision to create a network of CNG filling stations in the country was made in December 1983, at the same time the first station in the Moscow region was launched, located in the village of Razvilka at the intersection of the Moscow Ring Road and Kashirskoye Highway and designed for 500 gas stations per day. The station was equipped with Italian equipment, but Soviet-made compressors were already installed at the AGNKS-500 stations built in 1985-1987 on the Moscow Ring Road.

By the end of 2016, there were about 320 CNG filling stations. The largest owner and operator of CNG filling stations is Gazprom. For the comprehensive development of the gas engine industry, in December 2012 Gazprom created a specialized company Gazprom Gas Engine Fuel. By 2020, the company plans to increase its network to 480-500 points, and also install CNG refueling modules at existing liquid fuel gas stations of partner companies.

The largest consumers of natural gas motor fuel in Russia are the Stavropol and Krasnodar territories, Sverdlovsk, Chelyabinsk, Kemerovo and Rostov regions, as well as the republics of Kabardino-Balkaria, Tatarstan and Bashkortostan. In May 2013, the Government of the Russian Federation issued Order No. 767-r, which established targets for the use of natural gas in public and municipal transport for cities with a population of more than 100 thousand people. To stimulate demand, by 2020 in these cities it is planned to switch up to half of public transport and public utility vehicles to natural gas. As part of this initiative, natural gas buses are already operating in a number of cities. The first such buses appeared in St. Petersburg in 2013. In Rostov-on-Don and Volgograd, they plan to purchase more than 100 CNG buses for the World Cup.

Asia

Asia is the largest region in terms of the number of CNG vehicles. According to Asian NGV Communications, the total number of such vehicles in 2016 is more than 16.4 million. Largest countries by the number of CNG vehicles are located in Asia: China (more than 5 million cars), Iran (more than 4 million), Pakistan (more than 3 million), India (more than 3 million) and Thailand (475 thousand). As of February 2017, there are more than 17.2 thousand gas stations in Asian countries.

Pakistan is the world leader in gasification of vehicles (a third of the total vehicle fleet), ahead of Argentina and Brazil. Pakistan has launched the production of both CNG passenger vehicles, trucks and buses, and the production volume exceeds the volume of conversion. There are more than 2,300 CNG filling stations in the country, the construction of new ones is subsidized, import duties on gas cylinder equipment have been abolished, and the types of cylinders and sets of gas equipment are regulated at the state level.

Notes

Comments

Sources

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Now all over the world, liquefied gas is produced and used as a high-quality household and industrial fuel, which is a consequence of its main advantages. Namely: the possibility of the existence of liquefied gas at ambient temperatures and moderate pressures in both liquid and gaseous states. In liquid form, these gases are easily processed, stored, transported, and in gaseous form, they have better combustion characteristics than natural and artificial gases in the absence of harmful impurities.

Internal combustion engines running on gas fuel began to be developed much earlier than gasoline and diesel engines, however wide application They have only begun to be found in the automotive sector in recent years. Moreover, converting the engine to gas does not exclude the possibility of operating it on gasoline. Moreover, switching the engine from one type of fuel to another occurs right inside the car.

Gas fuel has many advantages over traditional liquid fuel. Perhaps the most important of these advantages for the average car enthusiast is the low cost of gas. Therefore, even though the same engine consumes slightly more gas than gasoline, the use of gas fuel turns out to be very profitable. One of the nice features of gas fuel is the fact that after emptying the fuel tank, the car will be able to drive another 2-4 km.

Two types of gas fuel are used as automobile fuel - liquefied petroleum, or hydrocarbon, gas and compressed compressed gas. Liquefied gas used as automobile fuel mainly consists of propane (C3H8), a gas mixture of butane (C4H10), obtained during the extraction of natural gas and oil, as well as various stages its processing in factories. and (about 1%) unsaturated hydrocarbons. Their chemical and physical properties provide sufficient power and efficient work engine.

Liquefied or compressed gas?

It is necessary to distinguish between liquefied and compressed gas. Compressed gas is mainly methane, which retains its gaseous state at almost any temperature and at any increase in pressure.

Liquefied gas is most popular among car owners. Converting a car to run on liquefied gas is easier and cheaper than converting it to run on compressed gas. Liquefied gas is in a cylinder under relatively low pressure - 16 atmospheres, and the high degree of rarefaction of compressed gas requires increasing this figure by 12-15 times. Therefore, to use compressed gas, bulkier and heavier refill cylinders with thicker walls are required. At the same time, the mileage of a car running on compressed gas, one refueling is half the mileage of a car on which equipment for liquefied gas is installed. However, compressed gas is also used as automobile fuel, since the reserves of methane in nature are very large and the cost of this type of fuel is low. Compressed gas vehicles are mainly trucks and buses used by businesses. In addition to cost, compressed gas has other positive differences: it is less explosive than liquefied gas, since it is very light and does not accumulate in open space if it leaks; Compressed gas, when burned, produces a cleaner exhaust; When using compressed gas, there is no need to drain the periodically formed condensate, which has an unpleasant odor.

Properties of liquefied gas

LPG or liquefied gas, a by-product of refined crude oil, is a gas at room temperature and pressure, and a liquid at 2Pa. The density of the liquid phase of a gas depends on temperature, with an increase in temperature the density decreases. Under normal conditions atmospheric pressure and a temperature of 15°C, the density of the liquid phase of propane is 0.51 kg/l, butane - 0.58 kg/l. The vapor phase of propane is 1.5 times heavier than air, butane is 2 times heavier. The boiling point of gasoline is higher than ambient temperature, and liquefied gas evaporates at lower temperatures. This means that the gasoline in the tank is, as a rule, in a liquid state at atmospheric pressure, and the liquefied gas in the cylinder is at a pressure corresponding to the ambient temperature.

Brands of liquefied gas

There are two brands of liquefied oil gas(GSN): PA - automotive propane and PBA - automotive propane-butane.

Indicator	PA-propane for automobiles	PBA-propane-butane for automobiles
Mass fraction of components, %:
methane and ethane	Not standardized
propane	90±10	50±10
hydrocarbons C4 and higher	not standardized
unsaturated hydrocarbons	6
volume of liquid residue at +40 "C	absent
at +45"C, no more	--	1,6
at - 20"C, not less	--	0,07
at -35"C, not less	0,07	--
including hydrogen sulfide,%, not more	0,01
Mass fraction of sulfur and sulfur compounds,%, no more	0,01
Content free water and alkalis	Absent

The PBA gas grade is allowed for use in all climatic regions at ambient temperatures not lower than -20°C. The PA brand is used in winter in those climatic regions where the air temperature drops below -20°C (recommended range -20°C...-25°C). Propane remains in a liquid state at temperatures below -42 degrees; for butane this temperature is -0.5 °C. In the spring, in order to completely exhaust reserves of PA grade liquefied gas, its use is allowed at temperatures up to 10°C. A higher temperature can lead to an undesirable increase in pressure in the gas supply system of the car and its depressurization.

Advantages of liquefied gas

Octane number

The octane number of gas fuel is higher than that of gasoline, therefore the detonation resistance of liquefied gas is greater than that of gasoline even top quality. This allows for greater fuel efficiency in an engine with a higher compression ratio. The average octane number of liquefied gas - 105 - is unattainable for any brand of gasoline. At the same time, the combustion rate of gas is slightly lower than that of gasoline. This reduces the load on the cylinder walls, piston group and crankshaft, allowing the engine to run smoothly and quietly.

Diffusion

The gas mixes easily with air and fills the cylinders more evenly with a homogeneous mixture, so the engine runs smoother and quieter. The gas mixture burns completely, so no carbon deposits form on the pistons, valves and spark plugs. Gas fuel does not wash away the oil film from the cylinder walls, and also does not mix with the oil in the crankcase, thus not impairing the lubricating properties of the oil. As a result, cylinders and pistons wear less.

Cylinder pressure

Liquefied gas differs from other types of automobile fuel by the presence of a vapor phase above the surface of the liquid phase. During the process of filling the cylinder, the first portions of liquefied gas quickly evaporate and fill its entire volume. The pressure in the cylinder depends on the saturated vapor pressure, which in turn depends on the temperature of the liquid phase and the percentage of propane and butane in it. Saturated vapor pressure characterizes the volatility of the hose. The volatility of propane is higher than that of butane, therefore its pressure at negative temperatures is much higher.

Exhaust

When burned, less carbon and nitrogen oxides and unburned hydrocarbons are released than gasoline or diesel fuel, without the release of aromatic hydrocarbons or sulfur dioxide.

Impurities

High-quality gas fuel does not contain chemical impurities such as sulfur, lead, alkalis, which enhance the corrosive properties of the fuel and destroy parts of the combustion chamber, injection system, lambda probe (sensor that determines the amount of oxygen in the fuel mixture), and exhaust catalytic converter.

Disadvantages of liquefied gas

Explosion hazard

When 1 liter of liquefied gas evaporates, about 250 liters of gaseous gas is formed. Thus, even a minor leak can be very dangerous, since the volume of gas increases by 250 times during evaporation.

This drawback can occur if gas equipment is installed incorrectly or the car owner fails to comply with the operating rules for such equipment. For gas to ignite, a higher concentration of this substance in the air is required than gasoline. However, the increased volatility of the gas allows dangerous amounts to accumulate faster and in larger volumes. Such a concentration cannot occur in a moving car, but in any case, if a characteristic odor is detected, the driver should turn off the gas supply to the engine and continue driving on gasoline. It is unacceptable to park the car in the garage if a gas leak is detected.

You can check the tightness of gas cylinder equipment by applying a soap solution with a brush to the joints of the pipelines. If soap bubbles appear in such places, the car has a direct path to a service station. It is prohibited to repair gas equipment yourself. Every two years, gas equipment installed on a machine must be inspected by specialists. Serviceable gas equipment is completely sealed. At least three shut-off devices, independent of each other, are installed on each pipeline leaving the cylinder.

Odoration

Since the gas is odorless, to determine whether the system is leaking, special substances - mercaptans - are added to the gas in a certain proportion. In their chemical structure they are similar to alcoholic substances, the general formula of which is R-SH. The presence of these substances, even in small quantities, is noticeable due to their unpleasant odor - if there is a smell of “gas” in a closed car, it means that the system is leaky and it is unsafe to operate such a car. Sulfur compounds of the odorant and the gas itself reduce the life of the gearbox due to intensive aging of membranes and rubber seals and cause corrosion of pipelines.

Refilling the fuel tank

It is impossible to completely fill a fuel cylinder with gas, since even a slight increase in ambient temperature leads to a significant increase in pressure in the cylinder. Therefore, when the fuel tank is filled to 80%, a special device in the gas equipment automatically closes the filling channel.

Undesirable operation in hot climates

Hot climates are not the best for operating gas fueled vehicles. In such conditions, in order to reduce the pressure in the fuel tank, the cylinder must be “moved out” a little before the car is parked.

Power reduction

Due to the lower heat of combustion of the gas-air mixture compared to the mixture of air and liquid fuel, a slight drop in engine power is observed - by about 10%. However, this does not have a significant effect on the dynamic characteristics of the car and, moreover, this can be partially eliminated if the ignition timing is set 3-5° earlier.

Injury hazard

Liquefied gas that comes into contact with human skin at low air temperatures can cause frostbite.

In addition to all of the above, we can note the need to replace air filters more often. Parts for gas equipment are still more difficult to find than for liquid fuel supply systems. The fuel tank takes up some part of the trunk. Finally, gas-powered cars sometimes have problems starting a cold engine.

TO category:

Automotive operating materials

Application of compressed natural gas

Natural gas consists mainly of methane and a small amount of other gaseous components. The composition of natural gas differs depending on its deposit and can be characterized by the following average values: methane 85...99, ethane 1...8, propane and butane 0.5...3, pentane up to 0.5...2, nitrogen 0.5...0.7, carbon dioxide up to 1.8% vol.

The heat of combustion of natural gases from individual deposits can reach up to 47 MJ/m3, but on average it is 33...36 MJ/m3. This value is almost 1000 times less than that of liquid petroleum fuel, which is the main disadvantage of natural gas as a motor fuel. Therefore, to ensure acceptable performance characteristics of a vehicle, especially the range when running on natural gas, it requires special preparation: compression to a pressure of 20 MPa or more, followed by storage on the vehicle in high-pressure cylinders or liquefaction using deep cooling to -162 °C with storage in special cryogenic (heat-insulated) containers. Due to its greater simplicity, natural gas is most widely used in compressed form.

Natural gas used in compressed form as a motor fuel is subject to the following specific requirements: absence of dust and liquid residue, as well as minimum humidity. The last requirement is related to the elimination of the possibility of clogging of the fuel system channels caused by freezing and precipitation of hydrates due to throttling and lowering the gas temperature when refueling the car. To ensure that these requirements are met, natural gas is purified using filtering, separation and drying equipment installed at gas filling stations.

In accordance with TU 51-166-83 “Compressed flammable natural gas, fuel for gas-cylinder vehicles,” two grades of LNG are intended for refueling gas vehicles (Table 7). Their difference is the different content of methane and nitrogen. The content of LNG is limited to the following products (g/m3, no more): hydrogen sulfide - 0.02; mercaptan sulfur - 0.016; mechanical impurities - 0.001; moisture - 0.009. The mass fraction of hydrogen sulfide and mercaptan sulfur in LNG should not exceed 0.1%.

Currently, the most widespread use of natural gas in compressed form is in vehicles with external mixture formation engines and forced (spark) ignition. Typically, a car with a carburetor engine is additionally equipped with cylinders for storing natural gas under high pressure, gas reducers, solenoid valves and other gas fittings that enable the engine to operate on gas. The universality of power supply for such a vehicle (gasoline or natural gas) is also its disadvantage, since it does not allow full use of the high detonation resistance of natural gas.

Experience in operating domestic gas vehicles powered by LNG has revealed a number of positive aspects that are similar to the advantages of operating on LNG. When using LNG as a motor fuel, the service life of the engine increases by 35...40%, the service life of spark plugs by 30...40%, and engine oil consumption is reduced due to an increase in the frequency (duration) of its changes by 2...3 times. At the same time, switching gasoline cars to compressed natural gas leads to a deterioration in a number of their performance indicators. Engine power is reduced by 18...20%, which leads to a decrease in maximum speed by 5...6%, an increase in acceleration time by 24...30% and a decrease in the maximum angles of climbs overcome. Because of large mass cylinders for storing high-pressure gas, the vehicle's carrying capacity is reduced by 9...14%. The driving range on one gas filling does not exceed 200…280 km.

Due to the presence of an additional fuel system, the labor intensity of maintenance and repair of a gas vehicle increases by 7...8%.

When natural gas is used as a motor fuel, its starting properties have been noted to be poor. Limit value engine cold start temperatures (without additional heating means) on natural gas are 3...8 °C higher than on LPG, and by 10...12 °C than on gasoline. The difficulty of starting is explained by the high ignition temperature of methane, as well as by the fact that during the ignition process, after several flashes, water is deposited on the spark plugs, bridging the spark gap.

An important advantage of gas fuels compared to oil ones is their better environmental properties, associated primarily with the reduction of emissions of harmful substances from engine exhaust gases. As is known, such substances are carbon monoxide CO, nitrogen oxides NO.t, total hydrocarbons CH and, in the case of using leaded gasoline, lead compounds. The use of gas fuels characterized by high detonation resistance eliminates the need to use a toxic anti-knock agent in thermal power plants and is therefore an effective factor in reducing environmental pollution with highly toxic lead compounds. The change in carbon monoxide content when the engine is running on gas and gasoline, depending on the composition of the fuel-air mixture, is approximately the same. However, given the possibility of a gas engine operating on leaner mixtures, its optimal adjustment ensures lower CO concentrations. The levels of CH emissions are also approximately the same, but their composition is fundamentally different. The harmful effects of hydrocarbons formed in combustion products of petroleum fuels are mainly associated with the formation of smog. When running on natural gas, the hydrocarbon part of the exhaust gas consists mainly of methane, which is highly resistant to smog formation.

Nitrogen oxides are the most toxic components of exhaust gases. Their maximum content for a gas engine is approximately 2 times less than for a gasoline engine. In addition, it can be further reduced by 2...3 times by adjusting the composition of the fuel mixture.

Based on the factors considered, the use of LNG-powered gas vehicles is most rational in intra-city freight transportation for servicing trade, household enterprises, etc. The use of natural gas is also promising in urban passenger vehicles due to the reduction in this case of harmful emissions that pollute the atmosphere. For this purpose, our country has begun producing LAZ-695NG gas buses and a gas modification of the GAZ-24-27 passenger taxi car.

The most popular vehicle running on compressed natural gas is the ZIL-1E8A truck. The main elements of the universal power system of this car, which ensures operation on gas and gasoline, are used in all other models of gas cars. The gas supply system of the EIL-138A vehicle (Fig. 23) includes eight carbon steel cylinders with a volume of 50 liters each, designed for working pressure 20 MPa. The cylinders are connected by high-pressure tubes and divided into two sections with separate shut-off valves 12. The cylinders are filled with gas using a valve. Before being supplied to the engine, the gas passes through a heat exchanger, in which it is heated by the hot exhaust gases of the engine. To reduce gas pressure, a high-pressure reducer is used (reduces pressure to 1.2 MPa) and low pressure 5. To monitor the operation of the power system, two pressure gauges located in the driver’s cabin are used.

Rice. 1. Schematic diagram of the fuel system of the ZIL-1E8A car

Rice. 2. Diagram of the gas-diesel fuel system of a KamAZ vehicle: 1 - engine; 2- injection pump; 3-gas dispenser; 4 - solenoid valve with filter; 5-high pressure reducer; 6 - gas heater; 7- valves; 8 - pressure gauge; 9 - low pressure reducer; 10- cylinder; 11- mixer; 12 - fuel pedal

The backup gasoline supply system includes a standard gas tank, an electromagnetic valve-filter, a gasoline pump and a carburetor-mixer. The transition from one type of fuel to another is carried out using solenoid valves.

The total capacity of the cylinders is 400 liters, which allows you to fill 80 m3 of gas with a gas cylinder installation weighing about 800 kg.

The difficulty of using gas fuels in diesel engines is due to their poor flammability, low cetane number and high ignition temperature. Therefore, to organize the operation of a diesel engine on natural gas, a gas-diesel process is used, which consists of supplying a dose of pilot diesel fuel to the cylinders, ensuring ignition of the gas-air mixture.

The gas-diesel process is used in a number of gas modifications of KamAZ family vehicles, as well as diesel buses. The gas-diesel power system of KamAZ vehicles includes 8...10 high-pressure gas cylinders. Compressed gas from the cylinders enters the heater 6, where it is heated using the heat of the coolant. In the reducer, the gas pressure is reduced to 0.95... 1.1 MPa. After this, through an electromagnetic valve-filter it enters a two-stage low-pressure reducer and then through a gas dispenser into a mixer, where it is mixed with air. The gas-air mixture is supplied to the engine cylinders, where at the end of the compression stroke a pilot dose of diesel fuel is injected into it through a conventional nozzle.

The drive of the control lever for the high pressure fuel pump regulator (HPF) is connected by a rod to the metering throttle valve drive. Using a special mechanism, the constancy of the pilot dose of diesel fuel in the gas-diesel engine operating mode is ensured, regardless of the position of the fuel pedal. Starting a gas-diesel engine and idling occurs only on diesel fuel. In other modes, increasing engine power is achieved by increasing the supply of gas fuel. The amount of supply of the pilot dose is 15...20% of the total fuel consumption.

Cars are refueled with natural gas at stationary automobile gas filling stations (CNG filling stations) or with the help of mobile gas refueling trucks (PAGZ). A typical CNG filling station provides 500 refills per day. Its technological scheme consists of five main functional blocks: separators, compressors, drying, gas accumulators and dispensers. A CNG filling station is a complex structure, including a production and technological building with a gas distribution and control room, a filling platform with parking boxes and external communications (connection to the gas network, water supply, power line, etc.). Gas coming from the external network undergoes separation, is then compressed by compressors to 25 MPa and supplied to the drying unit. Dry gas is sent for storage to batteries, from where it is supplied to refuel cars through gas filling stations.

Rice. 3. Technological diagram of a stationary CNG filling station

The number of refueling pumps at a CNG filling station is 8, the refueling time taking into account all operations is: for a truck 10...12 minutes, for a car - 6...8 minutes.

To refuel vehicles of motor transport enterprises remote from CNG filling stations, mobile gas refueling trucks (PAGZ) are used. A gas cylinder installation was installed at the PAGZ, equipped with units for charging the tanker with gas and distributing gas to cars. A gas cylinder installation usually includes three sections of gas cylinders with a volume of 400 fl each with a pressure of 32 MPa for stepwise refueling of vehicles using a non-compressor method. Refueling is carried out using two dispensing devices.

Chemical composition of gas. Application

The main part of natural gas is methane (CH4) – up to 98%. Natural gas may also contain heavier hydrocarbons - homologues of methane:

ethane (C 2 H 6),

propane (C 3 H 8),

butane (C 4 H 10),

as well as other non-hydrocarbon substances:

hydrogen (H2),

hydrogen sulfide (H 2 S),

carbon dioxide (CO 2),

helium (He).

Pure natural gas is colorless and odorless. To detect a leak by smell, add small quantity substances that have a strong unpleasant odor (so-called odorants). Ethyl mercaptan is most often used as an odorant.

Hydrocarbon fractions are valuable raw materials for the chemical and petrochemical industries. They are widely used to produce acetylene. The pyrolysis of ethane produces ethylene, an important product for organic synthesis. When the propane-butane fraction is oxidized, acetaldehyde, formaldehyde, acetic acid, acetone and other products are formed. Isobutane is used for the production of high-octane components of motor fuels, as well as isobutylene, a raw material for the production of synthetic rubber. Dehydrogenation of isopentane produces isoprene, an important product in the production of synthetic rubbers.

Compressed natural gas– compressed natural gas used as a motor fuel instead of gasoline, diesel fuel and propane.

Natural gas, like any other gas, can be compressed using a compressor. At the same time, the volume it occupies is significantly reduced. Natural gas is traditionally compressed to a pressure of 200–250 bar, resulting in a volume reduction of 200–250 times. Gas is compressed for transportation through gas pipelines to maintain the correct pressure inside the formation (reservoir pressure) during injection underground, and the production of compressed natural gas is an intermediate step in the production of liquefied natural gas. Compressed natural gas is cheaper than traditional fuel, and caused by its combustion products greenhouse effect less compared to conventional fuels, so it is safer for the environment. Storage and transportation of compressed natural gas takes place in special gas storage tanks. Biogas is also added to compressed natural gas, which reduces carbon emissions into the atmosphere.

Compressed natural gas as a fuel has a number of advantages:

· Methane (the main component of natural gas) is lighter than air and in the event of an emergency spill it quickly evaporates, unlike heavier propane, which accumulates in natural and artificial depressions and creates the risk of explosion.

· Non-toxic in small concentrations;

· Does not cause corrosion of metals.

· Compressed natural gas is cheaper than any petroleum fuel, including diesel, but exceeds them in calorie content.

· Low boiling point ensures complete evaporation of natural gas at the lowest ambient temperatures.

· Natural gas burns almost completely and does not leave soot, which worsens the environment and reduces efficiency. The exhaust flue gases do not contain sulfur impurities and do not destroy the metal of the chimney.

· Operating costs for servicing gas boilers are also lower than traditional ones.

Another feature of compressed natural gas is that boilers running on natural gas have greater efficiency - up to 94%, and do not require fuel consumption for preheating in winter (like fuel oil and propane-butane boilers).

Natural gas, cooled after purification from impurities to the condensation temperature (–161.5 0 C), turns into a liquid called liquefied natural gas. Liquefied gas is a colorless, odorless liquid whose density is half that of water. 75-99% consists of methane. Boiling point –158…–163 0 C. In the liquid state it is not flammable, non-toxic, non-aggressive. For use, it is evaporated to its original state. When the vapors burn, carbon dioxide and water vapor are formed. The volume of gas during liquefaction is reduced by 600 times, which is one of the main advantages of this technology. The liquefaction process occurs in stages, at each of which the gas is compressed 5-12 times, then cooled and transferred to the next stage. The actual liquefaction occurs during cooling after last stage compression. The liquefaction process thus requires significant energy consumption - up to 25% of the amount contained in liquefied gas. Liquefied gas is produced in so-called liquefaction plants (plants), after which it can be transported in special cryogenic containers - sea tankers or tanks for land transport. This allows gas to be delivered to areas that are far from the main gas pipelines traditionally used to transport conventional natural gas. Natural gas in liquefied form is stored for a long time, which makes it possible to create reserves. Before delivery directly to the consumer, liquefied gas is returned to its original gaseous state at regasification terminals. The first attempts to liquefy natural gas for industrial purposes date back to the beginning of the 20th century. In 1917, the first liquefied gas was produced in the United States, but the development of pipeline delivery systems delayed the improvement of this technology for a long time. In 1941, the next attempt was made to produce LNG, but production reached industrial scale only in the mid-1960s. In Russia, construction of the first liquefied natural gas plant began in 2006 as part of the Sakhalin-2 project. The grand opening of the plant took place in the winter of 2009.

Shale gas– natural gas produced from shale, consisting primarily of methane. The first commercial gas well in shale formations was drilled in the USA in 1821. Large-scale industrial production shale gas exploration was started by Devon Energy in the USA in the early 2000s at the Barnett Shale field, which drilled the first horizontal well in this field in 2002. Thanks to a sharp increase in its production, called the “gas revolution,” in 2009 the United States became the world leader in gas production (745.3 billion m3), with more than 40% coming from unconventional sources (coalbed methane and shale gas).

The world's shale gas resources amount to 200 trillion m3. In January 2011, economist A.D. Khaitun wrote about the possibility that shale gas “will repeat the fate of coalbed methane, with a significant drop in production growth during long-term exploitation of deposits, or the fate of biofuels, the vast majority of global production of which comes from America, and is now declining.”

Gas reserves and resources

World geological reserves of flammable gases on continents, in shelf zones and shallow seas, according to forecast estimates, reach 10 15 m 3, which is equivalent to 10 12 tons of oil.

The largest fields in the USSR were: Urengoyskoye (4 trillion m3) and Zapolyarnoye (1.5 trillion m3), Vuktylskoye (452 ​​billion m3), Orenburgskoye (650 billion m3), Stavropolskoye (220 billion m3), Gazli (445 billion m 3) in Central Asia; Shebslinskoye (390 billion m3) in Ukraine.

On the Yamal Peninsula and in adjacent water areas, 11 gas and 15 oil and gas condensate fields have been discovered, the explored and preliminary estimated (ABC 1 + C 2) gas reserves of which amount to about 16 trillion m 3, the promising and forecast (C 3 - D 3) gas resources are about 22 trillion m3. The most significant Yamal field in terms of gas reserves is Bovanenkovskoye - 4.9 trillion m 3 (АВС 1 +С 2), which will begin to be developed in 2012, and gas will flow into the new Bovanenkovo-Ukhta gas pipeline. The initial reserves of the Kharasaveyskoye, Kruzenshternskoye and Yuzhno-Tambeyskoye fields are about 3.3 trillion m 3 of gas.

Eastern Siberia and the Far East make up about 60% of the territory of the Russian Federation. The initial total gas resources on land in the East of Russia are 52.4 trillion m 3 , offshore - 14.9 trillion m 3 .

In the Russian Federation, gas production by JSC Gazprom alone in 2011 amounted to 513.2 billion m 3 . At the same time, the increase in category C 1 reserves reached a record level - 686.4 billion m 3, condensate - 38.6 million tons. In 2012, it is planned to produce 528.6 billion m 3 of gas and 12.8 million tons of gas condensate.

Condensate

Condensate – liquid product separation of natural gases. Presented mainly in liquid form normal conditions Hydrocarbons – pentane and heavier hydrocarbons of alkane, cyclane and arene composition. The density usually does not exceed 0.785 g/cm 3 , although differences with densities up to 0.82 g/cm 3 are known. End boiling point is from 200 to 350 0 C.

Distinguish raw condensate obtained during separation, and stable, obtained by deep degassing of raw condensate. The amount of condensate in reservoir gases is expressed either as the ratio of its volume to the volume of separated gas (cm 3 /m 3) and is called condensate factor. The amount of condensate per 1 m 3 of separated (free) gas reaches 700 cm 3. Depending on the value of the condensate factor, gases are “dry” (less than 10 cm 3 /m 3), “lean” (10-30 cm 3 / m 3) and “fat” (30-90 cm 3 / m 3). Gases characterized by a gas factor value of more than 90 cm 3 /m 3 are called gas condensate. At the Vuktyl oil and gas condensate field, the condensate factor is 488-538 cm 3 /m 3; natural gases from fields in Western Siberia are, as a rule, “dry”.

One and the same fact can be looked at from at least three points of view. So, the use of compressed natural gas in transport as a fuel can be said to be the lot of the poor and even beggars, but one can say that this is the choice of the thrifty and not accustomed to wasting money in vain, and there is also an opinion that methane is the fuel of the future and those those who are now switching to it are simply keeping up with the times and riding the wave of the nearby and promising mainstream. How to count - your choice!

The search for alternative sources of automobile fuel is a problem that has received the most attention in recent years. close attention. Rising oil and energy prices, tightening environmental requirements, saving fuel and lubricants - all this has become the main driving force in the search for alternative fuels for many countries. IN last decade In the 20th century, the third wave of popularity of natural gas, used as a motor fuel, began to gain strength in the global economy.
According to experts, this wave will reach its apogee by the end of the first quarter of the 21st century.

Natural gas
Natural gas, which is more than 90% methane, is now available almost throughout the world. And then what can we say about Russia!

According to experts, the use of natural gas is less affected by economic crises, which cannot be said about the oil and petroleum products market. Methane, whether fossil natural gas or biomethane, can be distributed through either an existing natural gas network or an existing fueling network. True, in some countries standing on the threshold of the industrial revolution, the issue of distribution networks has not yet been resolved. Methane required for road transport can be supplied to the consumer:
■ via the international gas pipeline network;
■ in the form of liquefied natural gas using tankers, road or rail tanks;
■ through local low-pressure pipelines (biomethane);
■ automobile tanks (liquefied biomethane).
Currently accepted international standards and the main types of vehicles suitable for methane delivery have been approved, and most regions already have certified suppliers of complete gas equipment for use in cars.

Undeniable advantages
Converting cars to natural gas does not require engine modifications and can significantly improve the environment, as the emission of toxic substances into the atmosphere is reduced.
Thus, emissions of carbon monoxide are reduced by 5–10 times, hydrocarbons by 3 times, and nitrogen oxides by 1.5–2.5 times. The noise level of a running engine is reduced by 2 times. Engine operation on compressed gas becomes softer, detonation does not occur in any mode, the octane number of the gas is 110. In addition, methane is lighter than air and if it leaks, it immediately evaporates, without creating an explosive mixture.

The use of gas fuel increases the service life of the engine and engine oil by 2 times, and spark plugs by 40%. With the same consumption per 100 km, the cost of gas is 2–3 times lower than the cost of gasoline or diesel fuel, which limits the growth of tariffs for transport services. The use of natural gas as a motor fuel reduces the dependence of transport on oil and petroleum products and frees up a significant part of them for use in areas where there is no alternative. Let us immediately note that further we will talk only about natural gas (methane: compressed or liquefied), and not about the propane-butane mixture, which is widely used in everyday life, as well as used in transport (the so-called liquefied petroleum gas).

Compressed or liquefied
Liquefied natural gas (LNG, liquefied natural gas) is produced by cooling natural methane gas to –162 °C. In the liquid state, the volume of gas is reduced by 600 times, which makes it possible to significantly increase the efficiency of its storage and transportation. Liquefied natural gas is transported in the same way as oil, in special tankers. In importing countries it is stored in tanks. In special terminals, LNG is heated, thanks to which it returns to a gaseous state, and is then pumped into the gas transportation system. Compressed natural gas (CNG - compressed natural gas) is the same methane, but in a gaseous state, under pressure up to 20 MPa. The consumer can immediately use this gas for his own needs. Experts continue to debate the merits and demerits of compressed and liquefied natural gas. Some believe that over time, when creating necessary conditions, liquefied natural gas will replace compressed gas, but others do not think so. Table 1 shows the comparative characteristics of liquefied natural gas and compressed gas.

It can be seen that CNG does not require special transport devices for delivery from the manufacturer, however, when using it, it is necessary to use special cylinders, which have a high cost and significant weight. As for the price of such fuel, in Russia the cost of a cubic meter of compressed gas is established by law - in the amount of 50% of the cost of a liter of AI76 gasoline. In this position, CNG significantly outperforms liquefied petroleum gas, for which the price is dictated by the market. However, it loses in cost of cylinders and equipment.
LNG abroad
Despite all the difficulties, abroad, in parallel with the use of CNG, the use of methane in motor vehicles and liquefied natural gas is expanding, this is especially significant for the United States. Thus, a wide network of gas stations has been created in the southwestern United States in the states of California, Arizona, Colorado, Texas, Pennsylvania and others. Large automobile corporations such as Mack, Ford, MAN pay the most serious attention to this issue. In Europe, the production of cars running on liquefied natural gas is carried out by companies such as MercedesBenz, MAN, BMW, etc. Liquefied gas as a motor fuel began to be used in Belgium, Finland, Germany, the Netherlands, Norway, France, Spain, Great Britain and other countries Europe.
CNG in the CIS
Today in Russia, CNG has become more widespread in the motor transport sector, especially for urban and municipal transport. In recent years, attempts have been made to expand the use of this type of fuel. Government organizations and private companies are involved in solving this problem. We already have many years of experience in operating automotive gas equipment running on CNG, especially within the structure of OJSC Gazprom.
In 2001, the Economic Council of the CIS proposed for implementation the interstate program “Use of natural gas as a motor fuel for vehicles for 2001–2005”, and partly thanks to it, CNG (compressed methane) has become most widespread in Russia and the CIS countries. , not liquefied natural gas.

CNG cylinders
To replace one liter of diesel fuel with the same amount of energy contained in gasoline, a fuel tank with a capacity of 15% larger will be required. If you use LNG, the tank volume will have to be increased by 70%, and when using compressed natural gas (methane), which is stored at an operating pressure of 200 bar (20 MPa), the fuel tanks must occupy a volume 4.5 times larger.

Therefore, the use of compressed natural gas is largely limited by the availability of special cylinders. Unlike other SGBV countries, in Russia this issue is being resolved quite successfully. Methane cylinders, as a rule, have a cylindrical shape and are conventionally divided into four types, including both cylinders traditionally made of steel and a lightweight version - cylinders using polymer composite materials based on glass carbon or organic fibers. Among these containers:
■ seamless steel cylinders;
■ metal-plastic cylinders (type 1), consisting of a thick-walled metal shell (liner) that carries the main load, and an external reinforcing shell made of a polymer composite material;

■ metal-plastic cylinders (type 2) - a thin-walled metal liner and a reinforcing shell made of a polymer composite material of the “cocoon” type over the entire surface;
■ composite cylinders - a polymer liner with embedded metal elements for connecting shut-off equipment and a load-bearing shell made of composite material.
In Russia there are 4 manufacturers of compressed natural gas cylinders (designed for a pressure of 20 MPa), two of them produce both all-metal and metal-plastic cylinders (see Table 2).

Companies such as Ruzkhimmash (Ruzaevka, Mordovia) and Orgenergogaz (a division of Gazprom), which produced these products, stopped producing automobile cylinders. Small batches are produced by NPP Mashtest (Korolev).
There are a couple of manufacturers of automobile CNG cylinders in Ukraine.
These are OJSC Berdichevsky Machine-Building Plant Progress and OJSC Mariupol Metallurgical Plant named after. Ilyich." In conditions of good demand for CNG and a developed network of gas filling stations in Ukraine, manufacturers note good demand for their products.
Almost all Russian manufacturers of cylinders are focused on the domestic market and the market of CIS countries, although the plant in Orsk has received an international certificate and has the ability to supply these products to non-CIS countries.
World practice shows that about 70–80% of cylinders used for methane transportation are all-metal. And this is despite the fact that the use of metal-plastic cylinders makes it possible to reduce the weight of the set by approximately 1.3–1.5 times, which is especially important when it is necessary to install several cylinders. This is due to the fact that effective technologies for the production of “composite” cylinders appeared much later and, of course, to the fact that metal-plastic cylinders are more expensive than all-metal ones. However, it should be noted that the use of lightweight cylinders is more profitable in the long term due to the weight savings of the vehicle, which leads to fuel savings, and the increase in the carrying capacity of the vehicle - the latter is especially important when it comes to freight transport.
LPG - gas equipment
In addition to the cylinders themselves, to install them on a vehicle, it is necessary to purchase additional appropriate gas cylinder equipment (LPG). The owner of a vehicle has two options - buy domestic gas equipment (produced by the Ryazan Automotive Equipment Plant, Votkinsk Gas Equipment Plant, etc.) or imported.
Price issue
Converting a car to run on CNG is not a cheap pleasure. Thus, the cost of a metal-composite cylinder is about 7.5–8.5 dollars/l, and an all-metal cylinder is 7 dollars/l. Thus, a serial metal-composite cylinder with a volume of 50 liters will cost the consumer $400, an all-metal one - $350, and this does not take into account the cost of gas cylinder equipment. If you plan to convert trucks or buses to CNG, then, depending on the required volume, you will have to install several cylinders, which will lead to a several-fold increase in the cost of the kit. Converting a passenger car to CNG will cost 1 thousand dollars, trucks and buses - more than 2.0–2.5 thousand dollars.

The cost of 50 liter car cylinders in the CIS countries for liquefied petroleum gas (propane-butane mixture) is 30–50 dollars, and the cost of converting a passenger car will be about 200–400 dollars, depending on the manufacturer and type of LPG.
Payback
According to expert calculations, taking into account fuel prices at the beginning of 2006, the payback period for motor vehicles when converting from gasoline to compressed gas, with an average annual mileage of 60 thousand km, ranges from 3 to 5 years, depending on the load capacity and type of vehicle. If we take into account the increased cost of gasoline since the beginning of the year and the greater mileage of the car, the payback period may turn out to be significantly shorter. If we take automotive and tractor equipment, for example K700 or T150, then thanks to the impressive fuel consumption, the payback period will be about a year.
It becomes clear why in Western countries and in our capital city transport is primarily switched to alternative gas fuel - the savings are too obvious and great.
World experience
By the end of 2005, there were over 4.6 million CNG vehicles in the world. The undoubted leaders among countries in this area are Argentina, Brazil and Pakistan. The first two countries have a fleet of gas-cylinder vehicles (NGVs) of over one million.
CNG filling stations - gas stations
Modern CNG filling stations must meet the following requirements:
■ low cost;
■ minimum dimensions and weight;
■ ease of installation and operation;
■ independence from electrical and heat supply systems;
■ maximum safety and comfortable working conditions for service personnel;
■ automation of station control;
■ efficiency of refueling with an accuracy sufficient for commercial accounting (up to 2%).
Manufacturers must be ready to offer the customer a sufficient range of CNG filling stations in terms of performance.

Argentina and Brazil have a well-developed system of automobile gas filling compressor stations (CNG filling stations). The number of CNG filling stations operating in these countries by the beginning of 2006 exceeded a thousand, which allowed Argentina to sell about 280 million cubic meters. m of gas per month, and Brazil - about 163 million cubic meters. m. It is noteworthy that the fastest pace in the construction of new CNG filling stations was noted in Pakistan and China, where the construction of more than 200 stations is planned. More than 100 CNG filling stations are being built in Brazil and Iran, but the leader in the number of gas-powered vehicles, Argentina, does not yet plan to build new CNG filling stations.
Russia and CIS
Despite significant reserves of natural gas, Russia is still inferior to Ukraine in the use of CNG and ranks 12th in the world ranking (see Table 3).

The Russian fleet of methane-powered vehicles is estimated at approximately 52 thousand. Today in Russia there are 215 automobile gas filling compressor stations, 87% of which belong to Gazprom, their total design capacity
is about 2 billion cubic meters. m/year, which would allow refueling 250 thousand cars per year. In 2005, 237 million cubic meters were sold through Russian CNG filling stations. m of natural gas (19.75 million cubic meters/month).
Thus, the load on existing gas filling stations in Russia is only 10–15%, but in general, in recent years, natural gas consumption by road transport in Russia has been steadily growing by 25–30% per year.

Douglas Consulting has also created its own network of multi-fuel filling complexes (MAZK) in Russia, which not only sells natural gas motor fuel, but also offers a full range of services for converting cars to gas. In recent years, other oil and gas companies have also paid attention to CNG. Thanks to Gazprom’s policy, regional gasification schemes in mandatory The construction of a CNG filling station is planned, and entire industries are gradually being converted to gas. Thus, JSC Russian Railways is successfully implementing a program to convert mainline and shunting diesel locomotives to gas.
A similar program for gasification of agricultural machinery is being prepared. The program “Russia's Energy Strategy for the Period until 2020” states that in the coming years, the consumption of motor fuel will grow most dynamically - by 15–26% by 2010 and by 33–55% by 2020. At the same time, liquefied and compressed natural gas will be used as motor fuel in the long term, along with traditional liquid petroleum products (equivalent to up to 5 million tons of petroleum products by 2010 and up to 10–12 million tons in 2020).
In Tatarstan, the Russian oil region, there are 9 automobile gas-filling compressor stations of Tattransgaz LLC with a total capacity of 70.6 million cubic meters. m per year, while their actual load is on average 7–8% of the designed capacity due to the small number of gas-cylinder vehicles. In 2006–2010 Tattransgaz LLC plans to put into operation 11 more CNG filling stations. In addition, there are dozens of gas distribution stations in the republic that, after additional installation of refueling compressor modules, can provide a significant amount of compressed natural gas for refueling vehicles. Thus, CNG in Russia has good prospects.
Ukraine
By the end of 2005, there were about 67 thousand gas-cylinder vehicles and 147 CNG filling stations in Ukraine. CNG sales reached 540 million cubic meters. m/year. Initially, most CNG filling stations were operated by the Ukravtogaz company, but then independent operators began to appear. However, despite the convincing advantages, the full potential of CNG has not yet been realized. According to estimates from structures working in the gas sector, Ukraine can annually re-equip 20–25 thousand vehicles.
One of probable causes Experts believe that the gap is due to the lack of modern production of metal composite cylinders in Ukraine. The two manufacturers mentioned earlier supply only all-metal cylinders to the domestic market, and even they cannot yet fully satisfy the needs of the market.
Among the tasks that need to be solved are also the development of the public health service network and support from the state and municipal authorities in this area.
Armenia
According to the Ministry of Transport of Armenia, currently about 38 thousand cars are equipped with gas installations, which is from 20 to 30% of cars operated in the country - quite high rate. The reason for the sharp increase in the use of CNG is the significant difference between the prices of compressed natural gas and traditional types of automobile fuel. According to forecasts, high growth rates in the conversion of cars to gas in this country will continue in the coming years; moreover, they can reach 20–30% per year.
Other members of the commonwealth
Tajikistan is experiencing a significant increase in natural gas consumption by road transport. Since 1997, after the relevant government decree was issued, the number of CNG filling stations increased by 2006 from 3 to 53. Basically, these are stations of low productivity. Today, the CNG filling station network in Belarus consists of 24 CNG filling stations in 17 cities of the republic, 5 mobile gas filling stations. The serviced fleet is 5.5 thousand gas-cylinder vehicles. OJSC Beltransgaz has developed a strategy for expanding the use of CNG, based on the national program for expanding the use of gas as a motor fuel, and a concept for the development of a network of CNG filling stations. By 2010, it is planned to increase the number of gas compressor units to 14.5 thousand and the volume of CNG sales to 72.3 million cubic meters. m/year.
In Moldova and Uzbekistan, the transition of vehicles to compressed natural and liquefied gas is not happening so quickly. Thus, in Moldova there are about 4.5 thousand gas filling stations and only 8 CNG filling stations. In Uzbekistan, less than 10 thousand vehicles running on gas fuel are operated (less than 1% of the total vehicle fleet), about 30.0 thousand tons of liquefied petroleum gas and 70–72 million cubic meters are used. m of CNG, although natural resources make it possible to significantly increase the amount of gas.

CNG brake
According to market analysts, there are problems preventing a larger transition to CNG. The main ones:
■ the high cost of converting vehicles to run on gas and often the lack of necessary funds for these purposes from farms, utilities, etc.;
■ lack of serial production of ready-made gas-cylinder vehicles by Russian automakers;
■ insufficiently developed network of CNG filling stations. In European countries, refueling points are located at a maximum distance of 30 km from each other, and in the Russian Federation there are highways where there is not a single CNG filling station for thousands of kilometers.

In addition, it is necessary to resolve issues of high wear and tear (especially in engine reserves) of the vehicle fleet of municipal property and government agencies, and the lack of preparedness of personnel in many regions of the Russian Federation to service vehicles running on CNG. In Russia, there is a limited number of companies that have certificates and are able to convert vehicles to run on CNG and timely inspect a vehicle with LPG. This problem is especially relevant for the regions.
Converting transport to natural gas is undoubtedly an important task and, with a reasonable approach, economically beneficial, but its solution is only possible with the direct participation of the relevant departmental organizations and the support of the state.

Russia, which has the world's largest reserves of natural gas, cannot afford not to take advantage of the situation to popularize CNG and possibly replace traditional fuels.

Sergey Kim October 2006

P.S. On my own behalf, I can add that my relative’s husband, who has been working as a taxi driver for more than 15 years, constantly switches his newly purchased cars to methane and after the conversion, the cost of fuel to run the car is reduced by about 3 times compared to gasoline.

This is, so to speak, direct experience.