Synthesized natural gas methanation equipment and process

Abstract

The invention belongs to the field of chemical engineering, and relates to equipment, a system and a method for a synthesized natural gas methanation process. In the methanation process, over-hot steam can be simultaneously generated, an aftertreatment system can be also arranged, when the operation load fluctuates within 30-120%, a methanation fluidized bed reactor is in a normal fluidized state, and the reaction can be completed by using only one methanation fluidized bed reactor; when the operation load fluctuates within 0-30%, the methanation fluidized bed reactor is in an abnormal fluidized state, a method that steam is compensated into a raw material gas is needed so as to maintain the normal fluidized state of a catalyst bed layer. As steam is compensated into the raw material gas which is fed into the methanation fluidized bed reactor, methanation reaction can move towards an opposite direction, and the conversion rates of CO and CO2 can be reduced; after water is separated out, the gas reacted from the methanation fluidized bed reactor can be further fed into an isothermal / low-temperature methanation reactor, the reaction can be completed, and a qualified natural gas can be generated.

Description

technical field [0001] The invention belongs to the field of chemical industry and relates to equipment, system and method for synthetic natural gas methanation process. Background technique [0002] At present, industrially synthesized natural gas mainly includes coke oven gas to natural gas and coal to natural gas. The key reaction of synthetic natural gas is methanation reaction, whose reaction formula is: [0003] CO+3H 2 =CH 4 +H 2 O △ H 298 =-206KJ / mol [0004] CO 2 +4H 2 =CH 4 +2H 2 O △ H 298 =-165KJ / mol [0005] The methanation reaction is a strongly exothermic reversible reaction. Under typical methanation reaction conditions, the adiabatic temperature rise per 1% CO conversion in the gas is about 72 °C, and every 1% CO 2 The adiabatic temperature rise for the conversion is about 60°C. [0006] In the existing methanation process, the methanation reactor is in the form of adiabatic reaction, that is, after the adiabatic reaction of the catalyst bed, the...

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Problems solved by technology

[0010] ①The reaction temperature is high, the equipment material requirements are high, and the safety is poor

If CO and CO in the inlet gas of the methanation reactor occur 2 When the content suddenly increases, the reactor is prone to over-temperature accidents, and the safety and reliability are poor

[0012] ② High catalyst cost

When the temperature is above 400°C, it is easy to produce carbon deposition reaction, which will cause carbon deposition on the surface of the catalyst, reduce the activity of the catalyst, and affect the service life of the catalyst

[0016] ④High power consumption

[0020] For the existing methanation fluidized bed reactor, there is a defect of small operating flexibility, and its normal operating load fluctuation range is between 30% and 120%.

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