A kind of method of synthetic urea solution

Abstract

The invention discloses a method of synthesizing a urea solution. The method comprises the following specific steps: (1) compressing carbon dioxide, and purifying the compressed carbon dioxide; (2) purifying ammonia, and delivering the purified ammonia; and (3) synthesizing urea solution. The decomposition rate of methylamine can be increased due to the self-stripping effect of ammonia, the low and medium-pressure decomposition and recovery load can be reduced, the power consumption be decreased accordingly, the heat from the condensation of methylamine separated under high temperature and high pressure can be utilized effectively, and the total energy consumption can be lowered. In addition, the production process has the advantages of high operating flexibility, high operating rate, low risk of explosion, convenience in installation and maintenance, secondary use of a condensate and no pollution. Furthermore, carbon dioxide and ammonia can be highly converted during the synthesis of the urea solution, the left unreacted carbon dioxide and ammonia can be recycled fully, nearly all the raw materials can be used, and the cost can be reduced greatly.

Description

technical field [0001] The invention relates to a method for synthesizing urea solution, which belongs to the field of chemical industry. Background technique [0002] Urea is a basic chemical product. my country is a large agricultural country and uses a huge amount of urea. The production capacity of urea is related to national agricultural and food safety. At present, the production processes adopted by large and medium-sized urea plants include: aqueous solution full circulation method, medium pressure combined urea method, carbon dioxide stripping method, and ammonia gas stripping method. [0003] Aqueous solution full circulation method: This method is adopted by most small and medium-sized urea plants in my country. The production process is mature, the operation is convenient and reliable, and the pumps and non-standard equipment are all domestically produced. It is characterized by a high conversion rate in the synthesis tower. Unreacted substances are decomposed by...

AI Technical Summary

Problems solved by technology

[0004] Carbon dioxide stripping method: Since the 1970s, my country has successively introduced more than a dozen sets of carbon dioxide stripping urea production units, most of which are large-scale units, which are characterized by short process flow, low synthesis pressure and low power consumption, but harsh operating conditions and corrosion It is more serious, the exhaust gas has the risk of explosion, and the operation flexibility is small

[0006] It can be seen that the above-mentioned mainstream urea production processes have obvious shortcomings and limitations

Images