乙烯装置裂解炉区域仪表改造

Instrumentation Modification in Cracking Furnace Area of Ethylene Plant

乙烯装置裂解炉凝液系统低压和常压闪蒸罐的液位计变送器引压管易堵塞,造成凝液外送泵抽空,将液位计变送器改造为双法兰毛细管差压变送器后,液位和凝液外送能够稳定控制。开工初期由于原料和稀释蒸汽流量表不稳定,经常触发SD-1和SD-2联锁,增加流量偏差报警能够避免此类现象发生。以裂解原料为加氢尾油的原料流量计,由于加氢尾油杂质较多、组分较重,流量显示不准且偏差较大,将流量计变送器改造为双法兰毛细管变送器后,流量趋势稳定。急冷系统稀释蒸汽发生器2#进料加热器发生泄漏,污染了乙烯装置的低压蒸汽管网和外送凝液,系统经过长时间置换恢复常态,在凝液外送管线上增加一块TOC在线分析仪表,能够及时发现装置有无泄漏,确保第一时间处理,从而保证生产稳定运行。

The level gauge transmitter tubing of the LP and atmospheric pressure flash tanks of cracking furnace condensate system in ethylene plant is easy to plug,causing the exhaustion of the condensate pump. After the level gauge transmitter modified into double flange capillary differential pressure transmitter, the liquid level and export condensate can be controlled stably. In the early stage of start-up,due to the instability of the raw materials and diluted steam flow meter,SD-1 and SD-2 are often triggered to interlock. By means of increasing the flow deviation alarm can avoid this phenomenon. Because the hydrogenated tail oil contains many impurities and heavy components,the flow rate display of the raw material flowmeter with cracked raw material as hydrogenated tail oil is inaccurate and the deviation is large. After the flowmeter transmitter is modified into the double flange capillary transmitter,the flow trend is stable. The 2# feed heater of diluted steam generator of quench system is leaked,which contaminates the low-pressure steam piping system and the export condensate of the ethylene plant. The system is returned to normal condition after a long time replacement,and a TOC online analyzer is added to the export condensate delivery line, which can detect the leakage of the unit in time and ensure the first time processing,so as to ensure the stable operation of the production.