Method for synthesizing ammonia through high-temperature electrolysis by taking low-concentration gas as fuel

Abstract

The invention discloses a method for synthesizing ammonia through high-temperature electrolysis by taking low-concentration gas as fuel, which comprises the following steps: preparing a proton conductor solid oxide electrolytic tank consisting of a porous Ni-BZCY cathode, a BZCY electrolyte and a porous LSCF-BZCY anode; preparing a low-concentration gas component as a fuel, and preparing humid air as an anode gas; and introducing fuel into a cathode gas channel of a solid oxide electrolytic tank, introducing humid air into an anode gas channel of the solid oxide electrolytic tank, and carrying out ammonia synthesis reaction on protons and nitrogen in low-concentration gas at 700 DEG C through external voltage. The comprehensive utilization rate of the low-concentration gas can be increased, the product ammonia gas can directly or indirectly reduce carbon emission and hydrogen production energy consumption in the synthesis ammonia industry, carbon circulation in the fossil fuel synthesis ammonia industry can be achieved, and energy conservation and emission reduction of the whole synthesis ammonia system are promoted.

Description

technical field [0001] The invention relates to the fields of synthetic ammonia production technology and gas utilization technology, in particular to a high-temperature electrolytic ammonia synthesis method using low-concentration gas as fuel. Background technique [0002] In recent years, my country's coal mine gas extraction volume has grown steadily year by year, reaching 17.8 billion cubic meters in 2018. For high concentration gas (C CH4 >30%) are usually transported by high or medium pressure, and sent to natural gas or coalbed methane pipeline network as civil, industrial fuel and chemical raw materials. However, due to the generally low gas concentration in underground drainage, most of them are low-concentration gas (C CH4 <30%), but due to the low concentration of methane and the difficulty of utilization, its utilization rate is less than 40%, and a large amount of low-concentration gas is directly discharged into the atmosphere. According to statistics,...

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Problems solved by technology

However, due to the generally low gas concentration in underground drainage, most of them are low-concentration gas (C CH4 <30%), but due to the low concentration of methane and the difficulty of utilization, its utilization rate is less than 40%, and a large amount of low-concentration gas is directly discharged into the atmosphere

For combustion power generation technology, this technology needs to go through a multi-stage conversion process such as thermal energy and mechanical energy to convert the chemical energy in the gas into electrical energy. The power generation efficiency is less than 30%, the noise is large, and air pollutants such as nitrogen oxides are emitted; However, the separation and concentration technology is complex and costly, especially for low-concentration gas with low methane content.

Even so, due to the limited increase in pressure, it is difficult to increase the conversion rate of ammonia, and the weakness of this method is that the process flow is too complicated, the safety factor is low, and the energy consumption is huge. People hope to find a method for synthesizing ammonia under low pressure or even normal pressure

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