提高加氢裂化装置加热炉烟气余热回收效率改造应用

Revamping for enhancing flue gas waste heat recovery efficiency of heaters of hydrocracking unit

中海油惠州石化有限公司3.6 Mt/a中压加氢裂化装置长期存在排烟温度高、加热炉效率低的问题。通过分析上述问题产生的原因提出了解决措施:当前工况排烟温度高于150℃,将空气预热器排烟温度控制在90℃以上,即可避免烟气露点腐蚀,可通过降低排烟温度来提高装置的加热炉热效率。由于低温段采用玻璃管模块,降低了露点腐蚀风险,同时模块化设计降低了维修频率,节约维护成本,故将原热管式空气预热器改造为板式及玻璃管模块组合式空气预热器。改造完成后,空气预热器出口排烟温度降低50℃,空气预热后温度提高80℃,各加热炉热效率提高约2百分点,节约燃料气150 m^3/h,每年节约运行费用400万元,每周期节约维护成本20万元,改造后装置节能效果显著。

The 3.6 Mt/a medium pressure hydrocracking unit of CNOOC Huizhou Petrochemical Co., Ltd. has long had problems of high exhaust gas temperature and low heating furnace efficiency. It is concluded that the dew point corrosion of the flue gas can be avoided by controlling the exhaust temperature of the air preheater above 90 ℃. The exhaust gas temperature of current working condition is higher than 150 ℃. Therefore, the heating furnace thermal efficiency can be improved by lowering the exhaust temperature. Since the glass tube module is used in the low temperature section, the risk of dew point corrosion is reduced, and the modular design reduces the maintenance frequency and saves the maintenance costs. It is proposed that the original heat pipe heat exchanger be transformed into a combined air preheater of plate type and glass tube module. After the renovation, the exhaust gas temperature at the outlet of the air preheater is reduced by 50, the preheated air temperature is increased by 80 ℃, the thermal efficiency of each heating furnace is increased by about 2 percentage point, the fuel gas is saved by 150 m^3/h, the operating cost is saved by 4 million yuan per year, and the maintenance cost is saved by 200 000 yuan per cycle. The energy-saving effect of the retrofitted device is remarkable.