Method for treating decomposed gas by low resistance vertical calandria type absorptive condenser

Abstract

The invention discloses a method for processing decay gas with a low resistance vertical tubular aspiration condenser, which contains the following: mixture gas being added from the head of condenser and distributed to every tube, dilute methanaminium solution being added from the head of condenser as an absorber, thus the gas- liquid mixture being formed in the tube, during the gas- liquid mixture flowing from up to down, partial ammonia and carbon dioxide being absorbed into liquid phase by dissolution and reaction and dissolving heat and reaction heat released and then shifted by water. The invention has merits as the following: the operation flexible, the absorption power improving more than 50%, the condensation heat controlled effectively. And the technique has a good application prospect.

Description

Technical field [0001] The invention relates to a method for absorbing mixed gas of ammonia and carbon dioxide, in particular to a method for processing decomposed gas with a vertical column-and-tube absorption condenser with low resistance drop. technical background [0002] The decomposition gas in the urea production process mainly contains ammonia, carbon dioxide, water vapor, and some inert gas, and its specific composition varies with the composition of the synthesis reaction liquid and the decomposition process parameters. The ammonia and carbon dioxide in the decomposition gas are recovered and recycled to the synthesis process. In the early stage of urea production, the "hot gas circulation method" appeared, because the hot NH 3 and CO 2 Direct compression is likely to cause technical difficulties such as crystallization in the gas phase and high-temperature compression, so it has not been industrialized. In the current various processes of urea production, the (m...

AI Technical Summary

Problems solved by technology

In general, the design is carried out on the shell side according to the condensation absorption process, that is, the shell and the tubes must contact the corrosive methylammonium liquid medium, so the whole equipment must be made of high-grade stainless steel, so that Causing high investment in equipment

[0005] Relevant domestic enterprises have also adopted pre-condensers in the capacity expansion of the circulation system, but their structure is of parallel type, and the absorption liquid in the follow-up section is not added as the absorbent, which leads to the blockage of the equipment after it is put into use and cannot continue to be used.

In addition, for the capacity expansion of the circulation system, more suggestions and discussions are to add a set of medium pressure, decomposition and absorption system, and replace the tempering water system with direct cooling water absorption, which is higher in investment costs than the parallel process, and This is very difficult for the heat balance and water volume control of the cyclic absorption part, and it is also to be verified in preventing the crystallization and blockage of methylammonium liquid

Images