What is the final disposal of the discarded SF6 gas?- SF6在线监测系统_SF6检漏仪_SF6传感器_SF6密度继电器

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What is the final disposal of the discarded SF6 gas?

发布时间：2016-05-10 来源：ydlcb 浏览次数：79次

In the last hundred years, the earth's climate is undergoing a significant change with global warming as the main feature. This global warming is caused by both natural climate fluctuations and the greenhouse effect, which is enhanced by human activities. Reducing greenhouse gas emissions and mitigating climate change are the main objectives of the United Nations Convention on Climate Change and the Jingdong Agreement. Therefore, our country is facing more and more international pressure to reduce greenhouse gas emissions. Therefore, the international joint environmental Convention strictly controls the emission of sulfur hexafluoride (SF6) gas.

The greenhouse effect means that gases such as carbon dioxide in the atmosphere can heat up the Earth's surface through short-wave radiation from the sun. At the same time, it blocks the Earth's surface from emitting long-wave radiation into space, thus warming the atmosphere. Because this role of carbon dioxide and other gases is similar to the role of "greenhouse", it is called "greenhouse effect", and carbon dioxide and other gases are called "greenhouse gases". At present, it has been found that there are six kinds of greenhouse gases emitted by human activities, they are carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, among which three kinds of fluoride. Among them, CO2 has a large impact on the greenhouse effect, accounting for 60%, while the impact of SF6 gas only accounts for 0.1%, but SF6 gas molecules have potential harm to the greenhouse effect, which is 25,000 times of the impact of SF6 gas molecules on the greenhouse effect. At the same time, the life of SF6 gas emitted into the atmosphere is particularly long, about 3400 years. Nowadays, the global annual emission of SF6 gas in the atmosphere of 5000 tons, therefore, the reasonable and correct use and management of SF6 gas, reduce emissions has reached the point of no remediation, in order to achieve as little as possible emissions requirements, to make a fruitful contribution to the cause of environmental protection in China.

Sulfur hexafluoride gas is a man-made gas, colorless, tasteless, non-toxic, widely used in the power industry circuit breakers, combined electrical appliances, load switches and other equipment. At present, more than 70% of the SF6 gas produced in the world is used in the power industry, and more than half is used in high-voltage electrical equipment. Today, SF6 annual consumption has reached 20,000 tons, and the SF6 concentration in the atmosphere is about 3.2ppt, which did not exist 10 years ago. What does that mean?

With the continuous investment in the construction of power system, the impact of SF6 leakage on China's atmospheric environment is increasingly serious, and the emission reduction of SF6 has been highly concerned in the domestic society. However, before there was no professional organization to deal with SF6 waste gas in China, if the SF6 waste gas is recycled in operation, the storage space and cost are the big problems faced by enterprises. Now relying on the SF6 gas recovery, purification and detection technology tested by Wevers, the SF6 waste gas purification and purification treatment equipment developed by Wevers is promoted and constructed in the country. The SF6 gas recovery and purification treatment center is carried out centralized purification treatment, unified detection and unified management of SF6 gas used in the test and on-site maintenance of switch equipment in various provinces. In order to realize SF6 gas recycling, SF6 gas to solve the pollution of the environment.

At present, with the rapid development of the power industry and the improvement of the level of technical equipment, a large number of SF6 circuit breakers and fully enclosed combined electrical appliances are constantly put into construction and operation. Up to now, the service life of sulfur hexafluoride electrical equipment has been more than 20 years, some have been overhauled, but most will gradually enter the overhaul cycle, there are a large number of SF6 need to be recovered and treated, SF6 gas recovery, utilization and prevention of environmental pollution is an urgent problem to be solved. In a long period of time, the recovery and treatment of SF6 in our country, especially the treatment and recycling work has not been well paid attention to, in a state of laissez-faire, there is no perfect and unified management mechanism and mode, and the gas use unit can not purify and recycle the gas after recovery, which not only brings security risks, but also causes pollution to the environment. In recent years, under the attention of the state, some domestic units have carried out some research and management methods of recycling and treatment equipment, and achieved some successful experience.

After the SF6 gas taken out of the electrical equipment is recycled, most of the gas can be reused, but some of the gas still cannot be recycled, and there is no other use. The final treatment of this part of the discarded SF6 gas is carried out to make the SF6 gas ultimately compatible with the environment and avoid entering the ecological environment cycle.

The final treatment method of Wevers is to heat treat the waste SF6 gas, heat SF6 gas to more than 1000℃, SF6 begins to decompose into ions and react with other substances, mainly react with hydrogen and oxygen to form SO2 and HF, when the treatment temperature reaches 1200℃, the conversion rate of SF6 gas can reach 99%. The products of the reaction are absorbed by Ca (OH) 2 (lime) solutions and form solid sulfates and fluorides, such as calcium sulfate (gypsum) and calcium fluoride (fluorspar).