Technique for preparing ammonia from urea by pyrolysis method

Abstract

The invention discloses a technique to prepare ammonia from urea through thermolysis, comprising the steps that: step 1: a storage and dissolution system (1) for urea particles is set; step 2: a storage system (2) for urea solution is set; step 3: an urea thermolysis system is set; step 4: a waste liquid treatment system (4) is set; step 5: all systems of the whole technique are communicated; step6: urea particles are stored and dissolved; step 7: urea is cleaved and ammonia is acquisited; and step 8: waste liquid is treated. The preparation method of ammonia of the invention has the advantages of low cost, simple operation, needing not high pressure, quick respond (the reaction can begin in 5 to 30 sec.), various heating means, and gas fuel or diesel and so on can be used.

Description

technical field [0001] The invention belongs to the field of flue gas denitrification, and in particular relates to a preparation process of denitrification reducing agent-ammonia. Background technique [0002] Selective catalytic reduction (SCR) refers to the reaction of nitrogen oxides (NOX) in flue gas with NH3 as a reducing agent under the action of a catalyst to generate non-toxic and non-polluting N2 and H2O. There are three kinds of substances that can produce denitration reducing agent NH3: liquid ammonia, ammonia water and urea. [0003] Anhydrous ammonia, also known as liquid ammonia, is a hazardous chemical. Anhydrous ammonia leaks into the air and forms clouds with water in the air, which is not easy to spread and poses a hazard to the personal safety of nearby people. The explosion limit of the mixture of ammonia vapor and air is 16% to 25%. If the mixture of ammonia and air reaches the above concentration range, it will burn and explode when exposed to an ope...

AI Technical Summary

Problems solved by technology

The pyrolysis method does not have a set of mature technology, and the urea hydrolysis method is not commonly used to produce ammonia. Moreover, there are mainly the following problems:

[0006] (1) Large water consumption;

[0007] (2) easy to generate residual urea polymer;

[0008] (3) The hydrolysis process requires high temperature and high pressure operation, which is prone to safety problems;

[0009] (4) The cost is relatively high;

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