Study On Technology And Application Of Petrochemical Equipment By Laser Cleaning

Laser cleaning is a kind of surface engineering technology that uses high-energy laser to remove the substrate surface attachment.It was first used in the field of microelectronics.Due to its advantages of green,high efficiency and high precision,it has been gradually demonstrated and applied in mold,construction,aerospace,high-speed rail and other fields,which is known as the most potential cleaning technology in the 21st century.As a pillar industry of national economy,there are few reports on the application of laser cleaning technology in petrochemical industry.In this paper,the petrochemical equipment is used as the application object,and the cleaning process,cleaning machine transformation and practical application are carried out through the experimental method.Finally,the laser cleaning process parameters,application occasions and new cleaning machine recommended under the existing conditions are explored.The purpose is to promote the engineering application of the technology in petrochemical industry.The main research contents and conclusions are as follows:(1)The existing 200W hand-held laser cleaning machine is used to clean petrochemical equipment.The results show that the laser has a good ability to remove oxide layer,rust layer,oil stain and welding black skin on the surface of petrochemical equipment made of carbon steel.The thicker oil stain is easy to be cleaned,but the thicker rust layer and welding black skin are not easy to be cleaned.The stainless steel substrate could be burned by laser and form irregular scratches,and further process research is needed.And it is necessary to improve the laser cleaning machine to adapt to the working environment of petrochemical plant.(2)The laser cleaning technology of black skin and oil stain of stainless steel weldment are studied by setting up the process platform.For welding black skin and greasy dirt,heavy sweeping of 200W,light sweeping of 40W and frequency of 130KHz are adopted.For welding black skin,the parameters with good cleaning effect are a speed of 6500mm/s,an arrangement distance of 0.05 mm,four times of heavy sweeping,one time of light sweeping.The parameters with high cleaning efficiency are a speed of 3900 mm/s,an arrangement distance of 0.03 mm,one time of heavy sweeping and one time of light sweeping.For oil pollution,the parameters with good cleaning effect are a speed of 7800 mm/s,an arrangement distance of 0.06 mm,one time of heavy sweeping,one time of light sweeping.The parameters with high cleaning efficiency are a speed of 10000 mm/s,an arrangement distance of 0.08 mm,one time of heavy sweeping.(3)The tensile and bending tests are carried out on the stainless steel weldments which are not cleaned,laser cleaned and laser over cleaned.The test results show that all the weldments conform to the acceptance standard of mechanical property tests of product welded test coupons for pressure equipments(NB/T 47016-2011),which proves that the impact of laser cleaning on the static strength mechanical properties of petrochemical equipment welding area meets the engineering requirements.Laser cleaning is a safe cleaning method.(4)According to the needs of petrochemical industry,the shortcomings of the existing laser cleaning machine are analyzed,and a new laser cleaning machine is developed,and some petrochemical equipments are cleaned,forming cases of laser cleaning in the petrochemical industry.Among them,laser cleaning technology is recommended for cleaning the head groove,local area with serious corrosion,plate connection area difficult to be grinded by grinding wheel,nozzle,end face of interface,small area of stainless steel,weld joint,etc.However,this technology is not recommended for cleaning the large area of plate,outside and inside of cylinder and large area of preheater head.And the technological procedure and safety management system of laser cleaning are proposed.