环己酮装置脱氢工序导热油加热系统技术改造

Technical transformation of thermo oil heating system in dehydrogenation process of cyclohexanone plant

介绍了环己酮装置存在的蒸汽能级利用不合理、环己醇脱氢工序工艺加热炉烟气排放达不到新执行标准等生产运行问题,提出对导热油加热系统的工艺加热炉进行技术改造,比较了以液化气为燃料的燃烧炉进行低氮燃烧改造或蒸汽加热器直接加热导热油2种方案的优缺点及可行性。结果表明:使用低氮燃烧器,技术控制较复杂,不便于操作人员掌握,无法保证烟气排放指标达到标准要求;停用工艺加热炉、改用蒸汽加热器直接加热导热油,技术控制简单,同时可实现蒸汽的梯级利用;在蒸汽加热技术改造中,新增2台蒸汽加热器分别对应2套脱氢反应系统,利用4.0 MPa蒸汽显热加热导热油,蒸汽经利用后再继续作为醇塔再沸器、脱氢进料蒸发器的热源,改造后加热系统运行平稳,实现了4.0 MPa蒸汽的梯级利用,且无烟气排放;改用蒸汽加热器加热导热油,可省去液化气燃料,每年可创造节能效益约800万元。

The problems existing in the production and operation of cyclohexanone unit,such as unreasonable utilization of steam energy level and substandard flue gas emission of heating furnace according to the new executive standards in cyclohexanol dehydrogenation process,were introduced.The technical reformation of the process heating furnace of thermo oil heating system was proposed.The advantages,disadvantages and feasibility of the low-nitrogen combustion reformation of liquefied gas combustion furnace or using steam heater to directly heat thermo oil were compared.The results showed that low-nitrogen burner required the complex technical control not easy for operators to master,which could not ensure that the flue gas emission index meets the standard requirements;the simple technology control and the cascade utilization of steam could be realized at the same time when the steam heater was used instead of the process heating furnace to directly heat the thermo oil;the 4.0 MPa steam was used to heat the thermo oil with sensible heat and was continuously used as the heat source of the alcohol tower reboiler and dehydrogenation feed evaporator through two newly added steam heaters corresponding to two sets of dehydrogenation reaction systems respectively in the steam heating technical transformation,and the heating system run smoothly and realized the cascade utilization of 4.0 MPa steam without flue gas emission after the transformation;and using steam heater to heat thermo oil can save liquefied gas and create energy saving benefit of about 8 million yuan annually.