Low-energy-consumption urea production technology and system adopting CO2 stripping method

Abstract

The invention discloses a low-energy-consumption urea production technology and system adopting a CO2 stripping method and solves the problems that the energy-saving effect is required to be improved, and the production cost and equipment investment are high in a conventional urea production technology. According to the technology, a medium-pressure decomposition recovery system connected in parallel is arranged additionally, so that the problem that medium- pressure low-pressure steam can not be used fully in a conventional high-pressure decomposition recovery system, which is bad for energy conservation, is solved; the low-energy-consumption urea production system through the CO2 stripping method comprises a high-pressure decomposition recovery system and further comprises the medium-pressure decomposition recovery system connected in parallel with the high-pressure decomposition recovery system; the high-pressure decomposition recovery system comprises a high-pressure CO2 stripping tower, a low-pressure decomposition tower and a flash drum connected with one another in sequence; the medium-pressure decomposition recovery system comprises a CO2 stripping tower; the urea stripping liquid outlet of the CO2 stripping tower is connected with the urea stripping liquid inlet of the low-pressure decomposition tower. The system provided by invention is simple, the low-pressure steam can be used effectively, capacity expansion is achieved, the energy-saving and cost-reducing effect is remarkable, and the equipment investment and operating cost are low.

Description

technical field [0001] The invention relates to a urea production process and system, in particular to a low energy consumption CO 2 Stripping urea process and system. Background technique [0002] Industrial urea production is based on CO 2 Gas and liquid ammonia are used as raw materials, which are processed into solid urea products through high-pressure synthesis, medium-pressure or / and low-pressure decomposition and recovery, vacuum concentration, and granulation. [0003] At present, the production processes of urea plants at home and abroad mainly include the following types: Netherlands Stamicarbon (Stamicarbon) CO 2 Steam stripping process, Italian Snamprogetti ammonia stripping process, Japan TOYO's ACES21 process, Switzerland Casale (Casale) high-efficiency synthesis process, aqueous solution full circulation process, etc. Among them, carbon dioxide stripping process and ammonia stripping process are the most competitive. [0004] Typical CO 2 The process flow...

AI Technical Summary

Problems solved by technology

However, due to the low grade of the by-product 0.45MPaA low-pressure steam, it is generally difficult to use, even if it is injected into CO 2 The efficiency of the compressor steam turbine (driven by the steam turbine) is also very low, and some factories have to empty it and waste it in vain

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