SU632294A3 - Fuel gas obtaining method - Google Patents

Description

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The invention relates to methods for producing fuel gases with a high calorific value.

A method of producing methane-enriched fuel gas is known by reacting liquid hydrocarbon fuel with hydrogen-containing gas and water vapor at elevated temperature and pressure on a nickel chromium catalyst l.

The disadvantage of this method is the necessity of carrying out the process on the catalyst.

The closest to the proposed technical essence and the achieved result is the method of producing fuel gas, which consists in that the hydrocarbon feedstock, in particular the liquid hydrocarbon, is subjected to incomplete combustion in the presence of water vapor with oxygen-containing gas at 9821927 C and a pressure of 2.1- 21O atm to produce gas containing nitrogen, carbon monoxide, hydrogen

The resulting synthesis gas is then swept away with a liquid hydrocarbon and steam. In this case, the hydrocarbon is converted to methane. Next, the conversion products are cooled to 38-316.

The disadvantage of this method is the relatively low calorific value (: gas capacity - 234 British thermal units per foot.

The aim of the invention is to increase the calorific value of the produced fuel gas.

This is achieved by the fact that in a known method the displacement of the combustion products with the hydrocarbon is carried out at 982-1093 C and the weight ratio of hydrocarbon and steam is 1; 0, 4-2, and hydrocarbon and products of combustion is 0.1-1 : 1, for 0.5-1O sec.

Carrying out the process in the specified fields makes it possible to produce gas with a calorific value of 400-6OO British thermal units per foot.

For incomplete combustion, both solid carbon-containing materials and liquid hydrocarbons and their mixtures are used to produce synthesis gas. Fuels such as petroleum coke, coal, coke cobalt production, natural gas, light oil fuels, gasoline ligroin fraction, gas oil, heavy liquid residual or distillate oil fuel, fuel oil, oil residues, crude oil can be used. etc. In the case of solid fuels containing carbon, along with an insufficient amount of hydrogen, water p-ar or liquid water is added to the zone for the incomplete combustion reaction, which contributes to the production of hydrogen in the synthesis gas . Kkuyu water and steam can also be used in conjunction with the hydrocarbon fuel to provide a moderate temperature of the partial combustion reaction and to increase the ratio of 1; between hydrogen and carbon monoxide in the composition of the synthesis gas. In the incomplete combustion zone, the fuel reacts with molecular oxygen at a temperature sufficiently high to form an exhaust gas stream consisting mainly of carbon monoxide and hydrogen along with small amounts of water vapor, carbon dioxide, methane and free carbon. . In addition, the sulfur compounds contained in the fuel are converted to hydrogen sulfide and COS. Gases containing molecular oxygen, such as air enriched with oxygen, containing about 45-95% oxygen, pure oxygen, etc., are used to partially burn the fuel, preferably in such a quantity that the atomic state of the oxygen to carbon, included in the composition of the fuel, was in the range of about O, 9-1,2. In the case of air being used as a gas containing molecular oxygen, the product synthesis gas is diluted with about 5% nitrogen. For high calorific value fuel gas production, dilution with nitrogen is undesirable. It is preferable to use a gas containing oxygen in an amount of 95% or more, although it is possible to use air to obtain a methane-containing gas with a lower calorific value. Partial oxidation reaction pressures can be applied in the range of approximately from atmospheric to 246.1 kg / cm (3500 pounds / inch). Preferably, the pressure during the reaction is maintained at the level required for the subsequent use of the product gas after the previous production process. According to the invention, the orchemical synthesis gas directly after the partial combustion stage is in contact with the vapor hydrocarbon mixture in the hydrocarbon conversion stage in order to convert the larger part of the hydrocarbon to methane. The hydrocarbon feedstock supplied to the hydrocarbon conversion stage includes light distillates, naphtha, gas oil, fractions of distillates obtained from oil refining. As a hydrocarbon feedstock, it is possible to use heavier hydrocarbon materials, such as crude oil, oil from which light fractions are distilled, lightly cracked oil, stripped oil, half-oil, fuel oil, residues from the distillation of oil, etc. However, such heavier hydrocarbons lead to the formation of significant amounts of resins and solid materials containing carbon, which requires practical devices to produce gas sufficiently pure for use as fuel. In the coal conversion stage The hydrocarbon and water vapor are thoroughly mixed to form a vapor mixture necessary to form evaporated hydrocarbons, or to form a fine homogeneous dispersion of carbon droplets in the water vapor in the case of hydrocarbons that are not iodine evaporated, and the weight ratio between water vapor and hydrocarbon is ranging from 0.4: 1 to 2: 1. The mixture of water vapor with water is in contact in the zone of hydrocarbon converse 1 with a hot synthesis gas, preferably at a temperature of about 1316 ° C (240 ° F) or higher. To convert most of the incoming hydrocarbon to methane within the conversion zone, the temperature is maintained at 986 ° 1O93 ° C (180O ° 2OOO ° F) with a residence time of the reactants in the conversion zone for about 0.5-10 seconds. In this reaction, all the hydrogen contained in the synthesis gas is consumed. In the hydrocarbon co-shear stage, certain amounts of resinous aromatic compounds, naphthalenes and solid carbon-containing materials are formed. These contaminants must be removed from the product gas by scrubbing in a scrubber, etc. The presence of water vapor in the mixture of 5,63 ss with the incoming hydrocarbon significantly reduces the formation of such heavy by-products. The weight ratio between the steam and the incoming carbon-hydrogen is 0.4; 1, helps reduce unwanted by-products. The residence time of the reacting substances in the hydrocarbon zone (about 0.5 sec) is enough to convert more of the hydrocarbons into the methane into the methane .. If the residence time is longer; than about 10 sec., reaffirming gases, consisting of hydrogen, carbon monoxide carbon dioxide, water and methane, in l to K) .. the tendency to go into equilibrium concentrations corresponding to the given reaction mopant values and pressure . At temperatures below about 98 ° C, C (1800 ° F) and a residence time of 0.5 to 10 seconds of conversion of the hydrogen-containing feed to methane is significantly reduced. At higher temperatures, greater than approximately 1093 ° C, exceeding approximately (2OOO F) j, there are no advantages in terms of conversion of incoming hydrocarbon raw materials at a specified X above the residence times of the Conversion ends with at temperatures of 982-1 °93 ° C ( ISOO 2000 ° F). The method is carried out as follows. Preheated carbon-containing fuel and preheated oxygen are fed to a generator to produce synthesis gas. The hepatore is an empty, capacitive reactor, footed with a refractory heat insulator. sew material. In a generator-carbon-containing fuel, it is partially burned with oxygen at 1103 1927 ° C to produce a synthesis gas consisting mainly of carbon monoxide and Woitzorde. In this case, synthesis gas may also contain some amount of carbon dioxide, water, COS, hydrogen sulfide, methane and soot. The synthesis gas, which has approximately the combustion temperature, passes from the generator to the carbon conversion zone, to which the preheated mixture of steam with hydrocarbon is fed and mixed with the hill by the synthesis gas coming from the generator at the mixing temperature of 882-1093 ° C (18OO-2OOO F) When the residence time of the reacting substances is 0.5–1.0 sec, more than 4 parts of the incoming hydrocarbon feedstock are converted to methane. The hydrocarbon hydrocarbon cone is a hollow reservoir that does not have a nozzle and is supplied. 113ol5 The jQjHaMeTp of the reservoir is chosen so that. ensure the turbulence of the passing through. This is a gas stream, and the length is selected taking into account the provision of the desired residence time of the reacting species during the conversion of the incoming hydrocarbon feedstock to methane. The turbulent gas flow in the hydrogen conversion zone provides a good mixture of reacting synthesis gas and a mixture of water vapor with a hydrocarbon, and also supports the required amount of soot, a tube of non-evaporated liquids and resins in the form of a suspension in a gas. The weight ratio is between steam and hydrocarbon, close-n-max, but in the range from 0.4: 1 to 2: 1 and between hydrocarbon and -; synthesis gas, in the example from 0.1: 1 to 1: 1, is selected to ensure that the desired concentration of methane in the product gas is present and to maintain the exit temperature of the hydrocarbon conversion zone in the range 982-1093 ° C (180 ° -2OOO ° P). The gas leaving the conversion zone contains methane, carbon monoxide, hydrogen, fuel, and small amounts of carbon dioxide, hydrogen sulphide and carbon sulphide (COs), samsha, tar, enters the cooling zone, which consists, consecutively, of the chamber for cooling (hardening) of the screen scrubber, separator. The gas phase after the separator enters the condenser, where most of the water vapor contained in it condenses, then undergoes COS by known grades, after which the resulting gas is already suitable for use. Example. Natural gas is converted by complete oxidation with oxygen; to synthesis gas having a mean weight of 13.043 and a typical composition, mol.%: Hydrogen59.5O Carbon monoxide35.5O Nitrogen0.36 Carbon dioxide3.65 Methane0.85 Conducted a series of experiments on the contact of hot synthesis gas with mixtures of water vapor with a hydrocarbon in the hydrocarbon conversion zone. The offgas after the hydrocarbon conversion zone is under-

Water is quenched to stop the reaction and remove soot and tar from the flue gas. After that, the gas is additionally cooled with water to approximately 52 ° C.

and heavy distillate oils. The experiments were carried out at elevated conversion temperatures.

The results of tests carried out under operating conditions corresponding to the invention under consideration are presented in the table.