Improvement measures and effects on heating stability of gas-phase heat medium system in polyester plant
The reasons for the low heating stability of the gas-phase heat medium system in a 300 kt/a four-kettle polyester plant,which affects the quality of polyester melt and spinning stability,were analyzed.And the technical improvements were car-ried out on the gas-phase heat medium system.The results showed that the gas-phase heat medium evaporator needed to be filled with oil once and degassed 2-3 times every 12 h,the manual control for oil filling and degassing operations caused significant temperature fluctuations in the heat medium evaporator and low heating stability of the gas-phase heat medium system before the improvement;the heating stability of the gas-phase heat medium system was significantly improved by changing the manual control to fully automatic control of oil filling and degassing operations,increasing the temperature of the gas-phase heat medium storage tank to 200℃,stabilizing the liquid level of biphenyl evaporator at 66%,stabilizing the degassing bag temperature at 285℃,and completely removing the low boiling substances from the gas-phase heat medium system;the fluctuation amplitude of the heat medium temperature decreased from±1℃to±0.5℃,the fluctuation amplitude of the reaction kettle temperature decreased from±0.6℃to±0.3℃,the fluctuation amplitude of the intrinsic viscosity of polyester melt decreased from 3.03%to 1.24%,and the average number of broken ends per 24 h during the spinning process decreased from 86.8 times to 40.8 times after the gas-phase heat medium system improvement;and the improvement of gas-phase heat medium system improved the heating stabili-ty of gas-phase heat medium system and the stability of melt quality and spinning conditions.
polyester plantgas-phase heat medium heating systemheating stabilityimprovement measuresimprovement effect
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