中文摘要：

低压蒸汽压力不够稳定，特别在管线末端常出现压力降低无法满足工艺需求的问题，生产中常采用中压蒸汽减温减压制得所需低压蒸汽，造成了能源的浪费。基于此，本文针对某炼化企业的实际情况，提出了用背压式汽轮机和蒸汽喷射泵分别代替减温减压器两套方案。经模拟计算，背压式汽轮机方案没有解决未加利用的低压蒸汽造成的能量损失。而蒸汽喷射泵方案，可以同时解决中压蒸汽减温减压造成的能量降级损失和未加利用的低压蒸汽造成的能量损失，具有更好的节能和经济效益。

英文摘要：

The pressure of low-pressure steam is usually instable, and decreases when it is transported in the pipeline with long distance because of pressure loss. Steam with a higher pressure will be used through a throttle valve, when the pressure of the low-pressure steam cannot meet the demand of the users, which causes the waste of energy. According to the actual situation of a refinery, two measures are proposed, which are using a back pressure steam turbine or a steam ejector to replace the throttle valve in this paper. The simulation results show that the turbine scheme cannot make use of the low-pressure steam, while the steam ejector scheme has better energy and economic benefits, for it can avoid the energy loss in the throttle valve and make use the low-pressure steam at the same time.