Non-isostatic alcoholization alkylation process for purifying raw gas for ammonia synthesis

Abstract

The invention discloses a non-isostatic alcoholization alkylation process for purifying raw gas for ammonia synthesis, which consists of medium pressure alcoholization, pressure boosting, high pressure alcoholization, high pressure alkylation, by carrying out alcoholization and alkanisation under different pressures to the raw material gas, the purifying procedure can be optimized, and the production costs can be lowered.

Description

technical field [0001] The invention belongs to the field of synthetic ammonia, and in particular relates to a new process of non-isobaric alcohol alkylation purification of synthetic ammonia raw material gas. Background technique [0002] Since the ammonia synthesis catalyst requires the poisons CO and CO in the syngas 2 The content must be ≤10ppm, so CO and CO in the syngas need to be 2 There are many ways to purify poisons, one of which is to remove CO and CO in syngas through methanoly reaction 2 : [0003] <chemistry num="001"> <chem file="200410014826_cml001.xml" / > < / chemistry> [0004] <chemistry num="002"> <chem file="200410014826_cml002.xml" / > < / chemistry> [0005] This reaction is under the pressure of 3.0 ~ 18MPa, the residual CO and CO in the tail gas 2 About 3-0.5%, as the pressure increases, the lower the value, for example: residual CO and CO under the pressure of 20-32MPa 2 About 50-800PPm, the by-product methan...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: ①The purification degree of alcoholization is not high under the medium pressure of 10-16MPa (CO+CO 2 About 0.5~1.0%), so useless CH is generated after alkylation 4 more, and consume more H 2

②All by-production of methanol under medium pressure will cause a large reduction in raw gas volume, which will cause a large difference between the medium pressure compression ratio and high pressure compression ratio of the compressor, making operation difficult and increasing energy consumption, which is especially prominent in the renovation project of old plants

③Another disadvantage is that the medium-voltage equipment is large and uses a large amount of catalyst, so the investment is relatively high

The disadvantages of this method are: ①All CO and CO 2 All are compressed to high pressure for alcoholization, which will significantly increase the compression work

③ When replacing the catalyst in the high-pressure alcoholization tower, the whole plant needs to be shut down, resulting in large economic losses

[0013] Therefore, there are obvious shortcomings in the two purifications currently used.

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