Method for synthesizing low pressure ammonia

Abstract

The invention discloses a method for synthesizing low pressure ammonia and belongs to the technical field of a synthesis ammonia process. The method is characterized in that a synthetic system adopts a method of a pure ruthenium based catalytic agent or a method combining an iron catalytic agent and a ruthenium catalytic agent, ammonia synthesis total pressure is 5-10MPa, ratio of hydrogen and nitrogen of feed gas is 0.5-1.46, and ammonia synthesis temperature is 300-425 DEG C, airspeed of the feed gas is 3000-15000h-1. Compared with a traditional process, after ammonia in gas at an outlet of a synthetic tower is separated, hydrogen content is greatly reduced, recirculation is not needed, and the gas can be directly sent to a hydrogen extraction device, so that a recycle compressor is not arranged. As for a field adopting a high pressure gas making process with synthetic pressure of 5-7MPa, an ammonia synthesis production line can remove the recycle compressor and a circulator, devices are simplified, power consumption is substantially reduced, and big economic benefits can be obtained accordingly.

Description

technical field [0001] The invention relates to the technical field of ammonia synthesis technology, in particular to a low-pressure ammonia synthesis method. Background technique [0002] In the traditional production line using iron-based ammonia synthesis catalyst, the ammonia synthesis pressure is mostly 15-30MPa, and the feed gas conversion rate is mostly around 10%-18%. Because the ammonia content in the gas from the synthesis tower is low, after the ammonia is separated, the remaining gas contains a large amount of unreacted hydrogen and nitrogen. In order to recover this part of the gas, the industry often adopts the recycling method to synthesize ammonia, that is, the unreacted hydrogen-nitrogen mixture is separated from the ammonia to replenish energy, merges with the fresh raw material gas, and re-enters the ammonia synthesis tower for reaction. Therefore, a circulating compressor must be installed in the process, and the synthesis process also increases the powe...

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Problems solved by technology

[0003] In order to overcome the deficiencies in the existing production of iron-based ammonia synthesis catalysts, the purpose of the present invention is to provide a low-pressure ammonia synthesis process to solve the shortcomings of the existing process of high energy consumption and high investment, improve the efficiency of the overall process and maximize the Method for low-pressure ammonia synthesis with reduced production costs

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