Sectional isobaric ammonia synthesis process

Abstract

The invention provides a sectional isobaric ammonia synthesis process. The sectional isobaric ammonia synthesis process comprises the following steps: (1) primary ammonia synthesis is performed on feed gases of synthetic ammonia in a first ammonia synthesis tower filled with an iron-based catalyst,wherein the synthetic pressure of the primary ammonia synthesis is 5-7 MPa, and the molar ratio of hydrogen to nitrogen in the feed gases of synthetic ammonia is (1.5-2.5):1; and (2) a mixed gas getting out of the first ammonia synthesis tower enters a second ammonia synthesis tower filled with a ruthenium-based catalyst to perform secondary ammonia synthesis, wherein the synthetic pressure of the secondary ammonia synthesis is 4-6 MPa. According to the sectional isobaric ammonia synthesis process, as the ammonia synthesis process is divided into two stages and performed under the specific pressures, specific catalysts and the specific hydrogen-to-nitrogen ratio, not only are technological requirements of synthetic ammonia satisfied and is stable technological operation guaranteed, but also the net value of ammonia at the outlets of the ammonia synthesis towers and the nitrogen and hydrogen utilization ratios are improved; and besides, each stage of synthesis is performed at low pressure, so that the energy consumption of the ammonia synthesis process is greatly reduced.

Description

technical field [0001] The invention belongs to the technical field of ammonia synthesis, and in particular relates to a segmented ammonia synthesis process. Background technique [0002] Ammonia is one of the important inorganic chemical products and occupies an important position in the national economy. Except that liquid ammonia can be directly used as fertilizer, nitrogen fertilizers used in agriculture, such as urea, ammonium nitrate, ammonium phosphate, ammonium chloride and various nitrogen-containing compound fertilizers, all use ammonia as raw material. Therefore, synthetic ammonia plays an important role in the national economy. The world's annual synthetic ammonia output has reached more than 100 million tons, of which about 80% of ammonia is used to produce chemical fertilizers, and 20% is used as raw materials for other chemical products. [0003] As we all know, synthetic ammonia is directly synthesized by nitrogen and hydrogen under high temperature, high pr...

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Problems solved by technology

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the defects in the prior art that the outlet ammonia net value is not high and the utilization rate of nitrogen and hydrogen is low, and then provide a high outlet ammonia net value, high nitrogen and hydrogen utilization rate, low energy Low energy consumption and stable operation of staged isobaric ammonia synthesis process

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