SU1188095A1 - Method of producing hydrogen-containing gas - Google Patents

Abstract

1. METHOD FOR OBTAINING HYDROGEN-CONTAINING GAS by acid conversion of natural gas on a solid fixed bed of heated catalyst at a temperature of 850-1150 ° C under a pressure of 1.7-40 atm. products and reducing the cost of the process, the initial mixture to the catalyst is fed at a temperature of 120-ZOO C, and the catalyst is heated by changing the direction of supply of the gas mixture to the opposite after 5-120 minutes. 2. The method according to claim 1, characterized in that the process is carried out (Q when the oxygen content in the source (L mixture 0.40-0.53 m per 1 m of natural gas.

Description

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The invention relates to the processing of gaseous hydrocarbons, namely the production of hydrogen and synthesis gas by the reaction of gaseous hydrocarbons, such as natural gas, with oxygen-forming gas-forming mixtures.

The aim of the invention is to increase the yield of target products and reduce the cost of the process.

The method is carried out as follows.

An initial reaction mixture of natural gas, water vapor and oxygen in a volume ratio of 1: 1: 0.45 with a temperature of 120 ° C at a pressure of 1.7 atm is fed to the catalyst preheated to catalyst. From direct contact with the heated catalyst, the mixture is heated. When the onset temperature of the reaction reaches 450-550 ° C, the oxidation of natural gas with oxygen begins. At the same time, the temperature on the layer length of 8-10 cm increases from 450-550 to 1000-1050 s. Simultaneously with the oxidation reaction of Natural gas, the endothermic reaction of natural gas with water vapor proceeds. In this case, the catalyst from the inlet side of the initial reaction mixture, while giving off heat, will be cooled to the temperature of the mixture. In the areas of the catalyst bed adjacent to the outlet, the temperature will decrease due to the endothermic reaction of natural gas with steam. As a result of such a mechanism of heat transfer about the length of the catalyst bed, a moving heat front (reaction zone) appears, the temperature profile of which is determined by the initial oxygen concentration and other parameters.

In order for the moving front of the reaction not to leave the catalyst bed, it is necessary to periodically change the direction of movement of the initial reaction mixture to the opposite every 40 minutes. At the same time, the area of the catalyst bed adjacent to the inlet of the reaction mixture, which was heated during the previous half-cycle due to the heat of the reaction of natural gas with oxygen, is cooled again. The heat front moves in the opposite direction. After a few switching in the reactor

periodic temperature and concentration profiles are established along the length of the layer. In this case, the contact time on the portion of the catalyst bed adjacent to the outlet will be small and the reaction mixture retains the composition characteristic of the maximum temperature zone where the main transformation occurs.

As a result of this process, the temperature of the converted gas at the outlet at 50-300s exceeds the temperature of the initial mixture, while in the reaction zone the temperature reaches 1.

Example 1. A reaction mixture containing reactants — natural gas: water vapor: acid — is supplied to the inlet of the autothermal conversion reactor at a volume ratio of 1: 1:: 0.45. Pressure 1.7 atm, the temperature of the mixture at the inlet.

Before entering the reaction mixture into the reactor, the catalyst bed is heated to

. At the beginning of the layer, a reaction zone is formed with a high (up to 1000 C) value of temperature. Through time, equal to the half cycle time, the flow direction of the reaction mixture

switch to the opposite, i.e. the withdrawal point of the reaction mixture becomes the insertion point and vice versa. In this example, the flow direction of the reaction mixture is changed after 5 minutes. The average per cycle hydrogen yield is 2.3 m per 1 m of natural gas with a degree of conversion of methane (dry gas) of 98%.

Example 2. The method is carried out analogously to example 1. The temperature of the mixture at the inlet is 150 ° C, the pressure is 1.7 atm, and the half cycle time is 40 minutes. The composition of the reaction mixture: natural

gas: water vapor: nitrogen: oxygen in a volume ratio of 1: 1: 0.75: 0.4. The yield of hydrogen is 2.3.5 natural gas.

Example 3, The method is carried out analogously to example 1, the temperature of the mixture at the inlet, pressure 40 atm, half cycle time 5 minutes. The composition of the reaction mixture: natural

gas: water vapor: carbon dioxide:: oxygen in a volume ratio of 1: 0.9: 0.4: 0.53, hydrogen yield 2.2 natural gas. 3 Example 4. The method is carried out analogously to example 1. The temperature of the mixture at the inlet, pressure 1.7 atm, the time of half-cycle is 10 minutes. The composition of the reaction mixture: natural gas: water vapor: oxygen in a volume ratio of 1: 1: 0.4. The hydrogen yield is 2.4 m / m natural gas. The composition of the reaction mixture: natural gas: water vapor, nitrogen, oxygen. 95 m of natural gas per 1 0.5 m of oxygen. Hydrogen yield 2.24 natural gas. Example 6. The method is carried out under stationary conditions (without interfering with the direction of the mixture feed). On the catalyst bed serves the reaction mixture with a temperature and the addition of 0.6 m of technical oxygen per 1 m of natural gas. At a pressure of 1.7 atm and a 98% methane conversion degree (dry gas), the hydrogen yield is 2.1 m / m of natural gas.

Claims (2)

1. METHOD FOR PRODUCING A HYDROGEN-CONTAINING GAS by acidic conversion of natural gas on a solid fixed layer of a heated catalyst at a temperature of 850-1150 ° С under a pressure of 1.7-40 atm. With preliminary heating of the initial gas mixture, characterized in that, in order to increase the yield target products and cheaper process, the initial mixture is fed to the catalyst at a temperature of 12 ° –3 ° C, and the catalyst is heated by changing the direction of the gas mixture supply to the opposite after 5–120 min. 2, the method of pop. 1, characterized in that the process is conducted with an oxygen content in the initial mixture of 0.40-0.53 m ³ per 1 m ^{3 of} natural gas. "* S