Technical Research On Reducing Energy Consumption Of Furnace In Atmospheric And Vacuum Pressure Unit

As the leading unit for refining and chemical enterprises,the atmospheric and vacuum distillation unit accounts for more than 20% of the total energy consumption of the whole plant.Therefore,it is necessary to explore how to reduce the energy consumption of the atmospheric and vacuum distillation unit.The energy consumption of atmospheric and vacuum distillation unit mainly concentrates on fuel,electricity,steam and water,accounting for more than 95% of the total energy consumption of the unit.At present,the energy saving of domestic atmospheric and vacuum distillation unit is mainly carried out around reducing the consumption of fuel gas,electricity,steam and water.This paper takes reducing energy consumption of atmospheric and vacuum distillation unit as the research subject,and takes the heating furance F-1/1 of 4.6 million tons/year atmospheric and vacuum distillation unit of Jinan Branch of Sinopec as the research object.The thermal efficiency of heating furnace is measured by the method of back-equilibrium thermal efficiency measurement.Because the method of back-equilibrium thermal efficiency measurement is less affected by external uncertainties,it is determined that the biggest source of energy consumption loss of heating furnace is high exhaust gas loss,and is also affected by the poor stability of branch feed of heating furnace.According to the experimental results,the main research direction is to improve the thermal efficiency of heating furnace and the stability of branch feed.During the overhaul window in 2017,the air preheater of atmospheric pressure furnace is upgraded and reformed.According to the characteristics of air preheater,its operating environment and advantages and disadvantages,the reformation scheme is determined to be the spoiler air preheater with low heat transfer coefficient but wide allowable temperature range and the spoiler air preheater with wide allowable temperature range.Heat pipe heat exchangers with high heat transfer coefficient but harsh environment are allowed to be used in series.In order to effectively solve the problem of instability of branch feed and branch temperature of reheating furnace,according to the predictive control algorithm of DMC,the main dynamic matrix control algorithm,Aspen DMC advanced control system is applied to model the reheating furnace system.The DMC controller calculates the optimal operating point within the effective control range of the parameters of reheating furnace,and controls the operating variables to control the target range.Controlled variable to stabilize feed rate and branch temperature of reheating furnaceThrough the modification of air preheater of large atmospheric pressure furnace in 2017 and the modeling and optimization of advanced control system in 2018,the fuel gas consumption of reheating furnace decreased by 1.44 kg Eo/t in the whole year of 2018,and the effect was remarkable.