低循环比条件下的延迟焦化技术分析

对中国石化洛阳分公司延迟焦化装置采取低循环比操作技术后的效果与存在的问题进行分析，并提出解决措施。采取低循环比操作后，焦化装置的液体产品收率和渣油加工能力均提高，同时装置的综合能耗降低，但存在加热炉结焦倾向增大、分馏塔塔底结焦、设备超负荷运行等问题。通过渣油进装置在线密度仪实时检测原料性质变化，根据原料性质变化及时调整循环比和加热炉炉管注汽量等，可改变渣油在炉管内的流动状态，避免加热炉炉管结焦；通过优化分馏塔塔底换热流程，增大循环油的流动性，可以减缓分馏塔塔底结焦；通过在小吹汽、大吹汽等阶段对分馏塔提前操作，可减弱低循环比操作对分馏塔的影响；通过增加循环油并入蜡油出装置流程，可解决低循环比操作下分馏塔塔底循环油去向问题，增大分馏塔平稳操作的灵活性。

ANALYSIS OF LOW RECYCLE RATIO OPERATION OF DELAYED COKING UNIT

The low recycle ratio operation has been adopted on delayed coking unit in SINOPEC Luoyang Company recently. The result shows that the liquid yield and unit throughput were increased by 3.57 and 30 percentage points respectively, and energy consumption was reduced by 41.03%. Meanwhile several measures have been provided to the problems resulted from the lower recycle ratio, such as the coking in furnace pipes and bottom of fractionator.