Process Optimization Of Long-term Operation Of Cracking Furnace In Ethylene Plant

The cracking furnace of the 460,000-ton/year ethylene plant of Lanzhou Petrochemical Company’s ethylene plant has the problem of short operating cycles and failure to reach the designed value.After comparison and analysis,it was found that the factors affecting the operating cycle of the cracking furnace are mainly four aspects: poor flame combustion in radiation chamber,partial flow led by low single-channel flow rate,improper cracking depth,and frequent leakage of the second quencher(SQE).This paper demonstrated the solutions to these problems and successfully extended the operating cycle of the cracking furnace.The poor flame combustion issue was solved experimentally through quantifying the flame combustion standard by referring to the brazier.The minimum bias flow rate of the gas-phase furnace was found via comparing the changes in pressure across the cross-section.We controlled the cracking depth by replacing constant COT by constant propane/ethane ratio to effectively slow down the cooking rate of the furnace tube at the end of the cracking furnace and ensure the yield.A simple modification of SQE was also applied to address the accumulation of superheated steam at the top of the SQE.