Purification, separation and purification device for mixed gas of sulfur hexafluoride and nitrogen gas and sulfur hexafluoride recovery, purification and purification method

Abstract

The invention provides a purification, separation and purification device for mixed gas of sulfur hexafluoride and nitrogen gas and a sulfur hexafluoride recovery, purification and purification method. A liquid outlet of a liquid nitrogen storage tank passes through a second cooling medium passage, a first cooling medium passage and a dry-type shell-and-tube heat exchanger sequentially and is connected with a nitrogen gas outlet, liquid nitrogen, as a cooling medium, flows out of the liquid nitrogen storage tank, then, passes through a solidifying tank, a liquefaction tank and the dry-type shell-and-tube heat exchanger sequentially and finally is discharged in a gas state, high-temperature gas discharged from a compressor is forcibly cooled in the dry-type shell-and-tube heat exchanger, pressurized gas SF6 can be relatively easily liquefied and then flows into the solidifying tank for low-temperature solidifying. According to the device and the method, the purification, separation andSF6 purification of SF6 / N2 mixed gas are achieved, the recovery rate of SF6 is high, nitrogen gas come from the solidifying tank can be further utilized, cold energy of the liquid nitrogen is fully utilized, and the process is environmentally friendly, energy-saving and emission-reducing, so that the device and the method have extremely high economic and environmental benefits.

Description

technical field [0001] The invention belongs to the technical field of recovery, separation and purification of sulfur hexafluoride gas, and in particular relates to a device for purifying, separating and purifying mixed gas of sulfur hexafluoride and nitrogen and a method for recovering, purifying and purifying sulfur hexafluoride. Background technique [0002] Sulfur hexafluoride (SF 6 ) gas is a gas with very stable chemical properties, and is widely used in high-voltage electrical equipment because of its excellent insulating properties and arc extinguishing properties. Of the approximately 8,500 tons of sulfur hexafluoride gas produced globally each year, more than half are used in the power industry. In practice SF 6 Gas also has some shortcomings: (1) SF 6 It is designated as a greenhouse gas by the United Nations Environment Program, and its greenhouse effect is 23,900 times that of the equivalent carbon dioxide, and it is listed as one of the six restricted green...

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Problems solved by technology

In practice SF 6 Gas also has some shortcomings: (1) SF 6 It is designated as a greenhouse gas by the United Nations Environment Program, and its greenhouse effect is 23,900 times that of the equivalent carbon dioxide, and it is listed as one of the six restricted greenhouse gases by the "Kyoto Protocol"; (2) SF 6 The molecular weight is larger, the liquefaction temperature is higher than that of ordinary gases, and it is easy to liquefy under the environment of high pressure and low temperature; (3) SF 6 The price of gas is high, so it is not suitable for electrical equipment with large gas consumption

In the existing solidification technology, it is difficult for industrial refrigeration equipment to reach a temperature of -100°C

In addition, in the existing vacuum freezing technology, in the process of vacuuming, part of the 6 SF at saturated vapor pressure 6 is also drawn away, causing SF 6 Gas waste, lower recovery rate

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