Research On Automatic Temperature Control System Of Postweld Heat Treatment For Spherical Tank

Spherical tank is widely used in petrochemical,energy and other industries,Which commonly used in the storage of flammable hazardous chemicals.Spherical tank in the process of using welds is often prone to cracking because of the presence of large spherical shell plate seam weld residual stress.Heat treatment after welding tank is an important step to eliminate residual stresses.Usually based on spherical shell outer surface temperature measured,with the artificial experience adjust heat regulating nozzle to control the heating rate and temperature.However,with further large-scale tank and temperature points to be collected there are dozens or even hundreds traditional heat treatment temperature is difficult to control the heat treatment process in accordance with the national standard of conduct.Post-weld heat treatment developed suitable Spherical tank temperature control system has become a major problem in the industry is currently experiencing.This article currently the most widely used spherical tank weld heat treatment study for the heat treatment temperature with a pure lag,nonlinear characteristics of the field of application of intelligent control more mature BP neural network algorithm PID-weld heat treatment temperature is introduced into the tank the issue of control.Work and innovation of this paper is as follows.(1)Studying GB12337-2014 technical requirements for tank-weld heat treatment temperature control,Using BP neural network PID and conventional PID control algorithm when tank valve in response to heat treatment simulation comparison,and use BP-NN-PID on-site tank heat treatment process simulation curve track,verify the former valve response speed.simulation results show that BP-NN-PID control algorithm tank-weld heat treatment can control the temperature.(2)Design small tank,an inner diameter of 2.8m,the wall thickness of 24 mm,4 pillars form,form spherical shell structure using an orange three-ball cans.This small tank heat build site experimental apparatus,including thermometer models and installation,insulation layer thickness and the laying step,production in the form of steel or the like.The small tank for heat engineering calculated the amount of fuel burning rate and heat treatment cycle for each stage,providing a reference for the heat treatment temperature control.Using Fluent software studies tank internal heat flow and temperature field simulation.(3)In the simulation analysis on the basis of post-weld heat treatment tank automatic temperature control system software design.Siemens Automation software use automatic temperature control system for the PC and the next crew of programming.Heating treatment to 2.8m experimental tank in Shandong company,were selected conventional PID control method and BP neural network PID control method is experimental the results showed that the temperature profile of the latter control the requirements more in line with GB12337-2014 better.Temperature heat treatment to achieve the next step after the domestic sphere welding automatic control of the foundation.