Research On The Fugitive-emission Of Sulfide-resistance Ball Valve

The sulfide-resistance ball valve is a ball valve to transport medium containing sulfide.When people are exploitation of oil and gas fields,they often meet with the corrosive medium is sulfide which H2S corrosion to play a leading role.The pipeline is the most economic way of long-distance conveying liquid or gas.In the long distance pipeline for the oil,natural gas,coal chemical industry,ball valve is the most used valve.But in these industrial fields widely exists H2S.Not only H2S is poisonous,but when the metal materials contact with it,various crack,cracking and other corrosion phenomena will happen.These corrosion forms will promote each other,then lead to material failure eventually and cause a lot of serious accident.In addition,when the leakage and fugitive emission from above industrial field are accumulated to a certain amount,not only have serious atmospheric pollution,but also harm to personnel health and life.The internationally recognized industry groups pay more and more attention to the tiny leakage which discharged into the environment from the valve.This tiny leakage is called"fugitive-emission".The research object of this article is fugitive-emission of sulfide-resistance ball valve.The main research content is external leakage with the naked eye can't identify.This research topic for the valve industry are difficult to solve the problem.This ball valve is high-end product which the international and domestic market is in short supply.This paper mainly presents the following four aspects:(1)Study and compare the difference between international mainstream standards in regard to the valve type testing of fugitive-emission,including the test medium,test method,mechanical circulation and acceptance criteria.Put forward a research target which make products to be competitive.(2)Study the key sealing technology that can reduce the fugitive-emission from ball valve.Lay the theoretical basis for the design and test?(3)This paper discusses the key factor in design of fugitive-emission ball valve.Study the corrosion mechanism of metal materials under acidic conditions with sulfide,and then found the basis and method for reasonable material selection.And the sealing solution is determined for the fugitive-emission of sulfide-resistance ball valve.(4)Test the fugitive-emission performance of the prototype valve.The fugitive-emission of sulfide-resistance ball valve is what research and development after the above work.According to the test requirements,tightness classes for stem and body seals with helium meet Class AH.Temperature classes is-46??200?.Mechanical-cycle class meets CO2,and the required minimum number of mechanical cycles shall be 1500 cycles.The ISO 15848-1 test certificate is obtained.Effectively improve the reliability of the valve,and to promote the environmental protection.The product's international competitiveness is also improved.