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New method for separating and recycling methyl isocyanate-decomposed tail gas

A technology for separation and recovery of methyl isocyanate, applied in separation methods, separation of dispersed particles, use of liquid separation agents, etc., can solve the problems of exhaust gas separation, recovery and utilization research, and achieve low energy consumption, high yield, and high separation rate Effect

Active Publication Date: 2010-07-21
HUNAN GOFAR FINE CHEM IND TECH CO LDT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Patents 86100286, 3969383, 2503270, 03136025, 02157003 and 02109959 only studied the synthesis process of isocyanate, and did not study the HCl and CHCl produced in the synthesis of isocyanate 3 Research on the separation and recovery of tail gas, and no relevant patents report on it

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] HCl and CHCl 3 The exhaust gas flows from the lower end to the upper end of the water washing tower, and its HCl quality is 640kg, CHCl 3 The mass is 150kg. The 5000kg washing solution at a temperature of 10°C is continuously sprayed downward from the upper end of the washing tower by the pump, and the exhaust gas is in countercurrent contact with the washing solution, and most of the HCl gas in the exhaust gas is absorbed by the washing solution. Then the remaining gas is condensed in two stages, the primary condensation temperature is 10°C, the secondary condensation temperature is -7°C, and CHCl is collected 3 condensate. A very small amount of gas that has not been absorbed and condensed is discharged at high altitude after being processed by the destruction tower. After the washing solution is left to stand for stratification, the lower organic phase is pumped into CHCl 3 Solvent recovery tank, the upper aqueous phase is pumped into the hydrochloric acid tank. ...

Embodiment 2

[0019] HCl and CHCl 3 The exhaust gas flows from the lower end to the upper end of the water washing tower, and its HCl mass is 649kg, CHCl 3 The mass is 147kg. The 5000kg washing solution with a temperature of 20°C is continuously sprayed downward from the upper end of the washing tower by the pump, and the exhaust gas is in countercurrent contact with the washing solution, and most of the HCl gas in the exhaust gas is absorbed by the washing solution. Then the remaining gas is condensed in two stages, the primary condensation temperature is 15°C, the secondary condensation temperature is -12°C, and CHCl is collected 3 condensate. After the washing solution is left to stand for stratification, the lower organic phase is pumped into CHCl 3 Solvent recovery tank, the upper aqueous phase is pumped into the hydrochloric acid tank. A very small amount of gas that has not been absorbed and condensed is discharged at high altitude after being processed by the destruction tower. ...

Embodiment 3

[0021] HCl and CHCl 3 The exhaust gas flows from the lower end to the upper end of the water washing tower, and its HCl mass is 645kg, CHCl 3 The mass is 149kg. The 5000kg washing solution at a temperature of 30°C is continuously sprayed downward from the upper end of the washing tower by the pump, and the exhaust gas is in countercurrent contact with the washing solution, and most of the HCl gas in the exhaust gas is absorbed by the washing solution. Then the remaining gas undergoes two-stage condensation, the first-stage condensation temperature is 5°C, the second-stage condensation temperature is -17°C, and CHCl is collected 3 condensate. After the washing solution is left to stand for stratification, the lower organic phase is pumped into CHCl 3 Solvent recovery tank, the upper aqueous phase is pumped into the hydrochloric acid tank. A very small amount of gas that has not been absorbed and condensed is discharged at high altitude after being processed by the destructi...

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PUM

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Abstract

The invention relates to a new method for separating and recycling methyl isocyanate-decomposed tail gas, which solves the problems of the cyclic utilization of HCl and CHCl3 resources and the environmental pollution. The method comprises the following steps that: (1) the methyl isocyanate-decomposed tail gas is in cyclic contact with water scrubbing liquid through a water scrubbing tower, most of HCl gas in the tail gas is absorbed by the water scrubbing liquid, and one part of CHCl3 gas is condensed by the water scrubbing liquid until the HCl weight content in the water scrubbing liquid meet the requirements; (2) after the step (1), gas which is not absorbed by the water scrubbing liquid passes through a primary condensation and a secondary condensation to condense the CHCl3 gas, and residual gas is treated by a destroying tower and is then discharged to the upper air; and (3) finally, the water scrubbing liquid containing the HCl gas is enabled to stand to stratify, a lower layer of organic phase is pumped into a CHCl3 solvent recovery tank, and an upper layer of water phase is pumped into a hydrochloric acid tank. The overall separating and recycling process has the advantages of low energy consumption, high separation rate and high yield, removes the pollution to the environment by the tail gas, and realizes the cyclic utilization of the HCl and CHCl3 resources, thereby achieving the purpose of energy saving and emission reduction.

Description

technical field [0001] The invention relates to the fields of environmental protection and resource recycling, in particular to a method for solving the problem of HCl and CHCl 3 A new method for the recycling of resources and the separation, recovery and utilization of methyl isocyanate decomposition tail gas that is problematic to the environment. Background technique [0002] Methyl isocyanate is an important intermediate in organic synthesis, and it is an important raw material for pesticides, artificial resins, and polyurethane plastics. Since the 1960s, due to the extensive use of high-efficiency and low-toxic carbamate pesticides, the commercial value of methyl isocyanate has greatly increased. For this reason, many research units and enterprises have conducted a lot of research on the synthesis of methyl isocyanate. At present, there are many methods for preparing methyl isocyanate, but industrial production still uses phosgene and methylamine as raw materials. In ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/68B01D53/70B01D47/00B01D5/00C07C17/38C07C19/04C01B7/07C07C265/04
Inventor 李国栋陈朝辉张敦河曹永亮梅院良黎辉良
Owner HUNAN GOFAR FINE CHEM IND TECH CO LDT
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