煤油进料换热器结垢机理浅析

STUDY ON COKING OF KEROSENE FEED HEAT EXCHANGERS

用自行设计制造的热油加热换热器,模拟煤油加氢装置原料煤油进料换热器。结果表明,煤油中溶解的氧气含量对焦垢的性状及换热器运行时间有很大的影响。氧气含量高,焦垢颗粒为块状、层状块、尺寸较大,焦垢松散,传热系数小,对换热影响大;氧气含量低,焦垢颗粒小,结焦致密,传热系数大,对换热影响小,换热器运行时间长。降低煤油中氧气含量可有效减少换热器焦垢的生成,延长换热器使用周期,减少装置安全环保隐患。

The coking in heat exchangers of kerosene hydrotreating unit is studied by experiment using hot oil to heat the heat exchangers. The results demonstrated that the O2 in kerosene had a great impact on coke shapes and operation cycle of heat exchanger. When higher O2 was present in kerosene, coke lumps or laminated coke lumps of larger sizes were formed. These lumps, which are loose in structure and small in heat transfer coefficient, have a greater impact on heat transfer. When kerosene has lower O2 content, the coke is small in particles and compact in structure. It has a greater heat transfer coefficient and little impact on heat transfer. Therefore, the operating cycle of heat exchanger is long. The ion in kerosene has catalytic performance. The reduction of O2 in kerosene can effectively reduce the coking in heat exchanger, extend its operation cycle and minimize the potential problems in safety and environmental protection of the unit.