Sulfur hexafluoride gas moisture harm is very serious- 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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Sulfur hexafluoride gas moisture harm is very serious

发布时间：2018-01-11 来源：ydlcb 浏览次数：34次

SF6 gas is a colorless, odorless, odorless, non-toxic, inert gas that is denser than air and is one of the six greenhouse gases discovered today.

SF6 gas is widely used in the high voltage electrical appliance manufacturing industry. Pure sulfur hexafluoride gas is a non-toxic and harmless asphyxiating gas, and there is no toxic sulfur hexafluoride.

However, the impure SF6 gas is very harmful to the environment and the human body and equipment.

Especially when sulfur hexafluoride gas contains excessive moisture, under the action of high voltage arc, it may be decomposed into HF, SO2, SOF2 and other toxic gases, which have a great impact on people and things around.

So how serious is the harm of sulfur hexafluoride gas moisture?

Where does the harm of sulfur hexafluoride gas moisture come from?

Why do we care so much about the harm of sulfur hexafluoride gas moisture?

We must first understand that the chemical properties of sulfur hexafluoride (SF6) gas are very stable, does not burn in the air, does not support combustion, and does not react with water, strong alkali, ammonia, hydrochloric acid, sulfuric acid, etc. Pure, high-purity sulfur hexafluoride gas is very safe and harmless when there is no asphyxiation conditions. However, due to poor gas extraction technology or insufficient storage of steel cylinder treatment, SF6 gas is not safe. Or long-term recycled SF6 gas will inevitably contain a certain amount of water, very small amounts of water can not pose a threat, but when the water content exceeds the standard, the harm of sulfur hexafluoride gas water is very great!

How harmful is sulfur hexafluoride gas moisture? Excessive moisture will harm insulation, affect arc extinguishing, and produce toxic substances. When the water content of the circuit breaker is high, it is easy to condensation on the surface of the insulation material, resulting in insulation decline, and flashover breakdown occurs in serious cases. Gas with high water content is decomposed under the action of electric arc, sulfur hexafluoride gas and water produce a variety of hydrolysis reactions, resulting in tungsten trioxide, copper fluoride and other powdery insulation, of which copper fluoride has a strong moisture absorption, attached to the insulation surface, so that the flashover voltage along the surface drops, hydrofluoric acid, sulfuric acid and other strong corrosion, corrosion effect on solid organic materials and metals. The equipment life is shortened.

The harm of sulfur hexafluoride gas moisture is not only for the equipment, in fact, the excessive moisture will also lead to SF6 gas and the toxic decomposition produced under the action of high temperature arc discharged into the atmosphere, damaging the body and harming the environment. The SF6 gas experts of Nuredett gas remind everyone that the harm of sulfur hexafluoride gas moisture should not be underestimated!

So why does sulfur hexafluoride gas have water in it? Where does the moisture in the sulfur hexafluoride gas come from? In fact, in the process of SF6 gas production will be affected by the material of the production equipment, process conditions and other factors, in addition to the water generated in the synthesis process, in the gas filling process may also be mixed with a small amount of water.

In order to prevent the possible harm of sulfur hexafluoride gas moisture, there are strict regulations for the quality indicators of SF6 gas, requiring manufacturers to provide biological test non-toxic certificates when supplying, and requiring the International Electrotechnical Commission (IEC) and many countries to develop quality standards for SF6 products. In addition to the water in the gas, the equipment may also be mixed with water! The moisture brought in by the insulation. The reason is that in the long-term operation, the water contained in the organic insulation material is slowly released, resulting in an increase in water content. Moisture brought in by the adsorbent. The reason is that the adsorbent activation treatment time is too short, and the exposure time to air during installation is too long. Water seeping through the seal. The reason is that the partial pressure of water vapor in the atmosphere is dozens of times or even hundreds of times that inside the equipment, and water infiltration under the action of pressure difference. The device is leaking. The reason is that the water vapor in the air at the inflatable interface, pipe joints, and sand holes of cast aluminum parts penetrates into the inside of the equipment, causing the rise of water. This relief is the cause of the possible harm of sulfur hexafluoride gas moisture.

How can we reduce the harm of sulfur hexafluoride gas moisture?

1. Before filling the gas, the water content of the gas must be measured, and the gas that does not meet the standard (stipulated in the relevant standards in China, the water content in the new SF6 gas shall not be large: 64 μL) shall not be used.

2. Optimize the shell design of the equipment and select materials with good density and poor thermal conductivity as the shell. Improve the sealing structure of SF6 circuit breaker, improve the processing accuracy and assembly quality of sealing surface, select high quality sealing gaskets, reduce the entry of external water vapor.

3. Strict process requirements, parts must be cleaned into the oven for drying treatment, if the parts themselves moisture is very small, even if the temperature rises, its trace moisture value can also meet the technical requirements.

4, to strictly factory testing and according to the temperature, the season to adjust the qualified standards of water value, such as winter can control the trace water value below 801μL /L, summer control below 120μL/L. In this way, it can meet the requirements of trace moisture value not exceeding 150μL/L at different temperatures.