Purification method for trifluoromethane

A purification method, trifluoromethane technology, applied in the field of purification of high-purity HFC, to achieve the effect of reducing workload, stable production process and reducing energy consumption

Active Publication Date: 2014-07-02
SINOCHEM LANTIAN +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It is still difficult to prepare high-purity trifluoromethane with a content of more than 99.99%

Method used

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  • Purification method for trifluoromethane

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Raw materials HCFC-22 and HF are passed into the reactor (1) to react at a speed of 140Kg / h and 35Kg / h respectively, the reaction temperature is 200°C, and the pressure is 5Kpa to form a reaction product flow (10), and the reaction product flow ( 10) A stream (11) containing HFC-23, HCl, HCFC-22 and HF at a temperature of 5°C is obtained after condensation in a heat exchanger. The stream (11) is washed with water by the water washing tower (3), and 0.8Kg / h high boilers are recovered, of which about 90% are chloroform. After alkali washing and drying, a stream (15) containing HFC-23, a small amount of HCFC-22 and chloroform is obtained, wherein HFC-23 accounts for about 93% by mass of the stream (15). The stream (15) is fed from the lower body of No. 1 rectification tower (6) for rectification. The rectification temperature is controlled at about 15°C and the pressure is about 2.4MPa. The top of the tower contains HFC-23 and a small amount of HCFC-22 And the stream (16)...

Embodiment 2

[0031]Raw materials HCFC-22 and HF are passed into the reactor (1) to react at a speed of 150Kg / h and 40Kg / h respectively, the reaction temperature is 260°C, and the pressure is 9Kpa to form a reaction product flow (10), and the reaction product flow ( 10) A stream (11) containing HFC-23, HCl, HCFC-22 and HF at a temperature of 15°C is obtained after condensation in a heat exchanger. The stream (11) is washed with water by the water washing tower (3), and 0.4Kg / h high boilers are recovered, of which about 95% are chloroform. After alkali washing and drying, a stream (15) containing HFC-23 and a small amount of HCFC-22 and chloroform is obtained, wherein HFC-23 accounts for about 96% by mass of the stream (15). The stream (15) is fed from the lower body of the No. 1 rectification tower (6) for rectification. The rectification temperature is controlled at about 7°C and the pressure is about 2.2MPa. The top of the tower contains HFC-23 and a small amount of HCFC-22. And the stre...

Embodiment 3

[0033] The raw materials HCFC-22 and HF are passed into the reactor (1) at a speed of 170Kg / h and 50Kg / h respectively for reaction, the reaction temperature is 350°C, and the pressure is 15Kpa to form a reaction product flow (10), and the reaction product flow ( 10) A stream (11) containing HFC-23, HCl, HCFC-22 and HF at a temperature of 25°C is obtained after condensation in a heat exchanger. The stream (11) is washed with water by the water washing tower (3), and 0.4Kg / h high boilers are recovered, of which about 92% are chloroform. After alkali washing and drying, a stream (15) containing HFC-23, a small amount of HCFC-22 and chloroform is obtained, wherein HFC-23 accounts for about 98% by mass of the stream (15). The stream (15) is fed from the lower body of the No. 1 rectification tower (6) for rectification. The rectification temperature is controlled at about 3°C ​​and the pressure is about 1.9MPa. The top of the tower contains HFC-23 and a small amount of HCFC-22. And...

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Abstract

The invention provides a purification method for high-purity trifluoromethane. The method comprises the following steps: carrying out condensation and separation on a reaction product by using latent heat of a reaction raw material HCFC-22 and then carrying out two-stage rectification so as to obtain HFC-23 with content of more than 99.99%. The method provided by the invention enables the prepared product to have high purity and has the advantages of low energy consumption and smooth, steady and safe generation technology.

Description

technical field [0001] The invention designs a method for purifying HFC, in particular relates to a method for purifying high-purity HFC. Background technique [0002] Trifluoromethane, also known as fluoroform, is a colorless, slightly odorous, non-conductive gas, and is an ideal substitute for haloalkanes. There are two main uses, one is in the semiconductor industry, used in the plasma etching of silicon dioxide and silicon nitride (plasma etching). The second is to use it as a refrigerant or a fire extinguishing agent. [0003] In the conventional process of using difluorochloromethane and anhydrous hydrofluoric acid to prepare trifluoromethane at 200 ° C ~ 350 ° C, the temperature of the material gas after the reaction is relatively high, which will increase the difficulty of the subsequent treatment of the by-product hydrochloric acid, so It needs to be cooled by heat exchange. Common cooling methods include graphite heat exchanger or falling film absorption. These c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C19/04C07C17/20C07C17/383
Inventor 吕正璋黄挺秀洪健陈忠民程元育李成东
Owner SINOCHEM LANTIAN
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