LNG接收站气化外输单位能耗计算

由于气化外输单位能耗不仅是LNG接收站重要运行指标,也是节能研究的基础,因此展开了接收站气化外输单位能耗的研究。首先,介绍了气化外输涉及的工艺和设备,然后计算了低压泵、高压泵、海水泵等耗电设备的电功率,并求得火炬长明灯和SCV的气耗。之后,求得夏季以ORV作为气化器最小外输工况,气化外输1t天然气,单位能耗为4.625kgce/t(1kgce的热值为20938kJ);冬季以SCV作为气化器最大外输工况的单位能耗为25.83kgce/t。对比发现,运行SCV的单位能耗远大于运行ORV。最后,通过计算机编程确定外输天然气流量与单位能耗对应数据,并作出关系曲线,找到气化外输最低单位能耗为1.946kgce/t,与之对应的外输天然气流量为690t/h。同时发现,从整体考虑,随着外输天然气流量的增加,单位能耗呈下降趋势,但增加运行设备的瞬间,单位能耗则会反向快速增加。

A calculation on the unit energy of the vaporization-transportation at LNG terminal

The unit energy consumption of vaporization-transportation is not only an important operation indicator, but also the basis of energy-saving study at LNG terminal. This paper addressed the issue in the following process:Firstly, the process and equipment involved was introduced; subsequently, the electric power of low-pressure pump, high-pressure pump, seawater pump and other power consumption equipments were calculated, as well as the gas-consumption of torch ever-burning lamps and SCV. After that, the unit energy consumption was obtained as 4.625 kgce/t if 1 t natural gas was vaporized and transported in the minimum transportation conditions with ORV as vaporizer in summer, and the value shifted to be 25.83 kgce/t in the maximum transportation conditions with SCV as vaporizer in winter. It was found in the comparison that the unit energy consumption of running SCV was much higher than the running ORV. Finally, the relationship between the natural gas flow of transportation and the unit energy consumption was determined by computer program, as showing in the curve. From the curve, it was found that the minimum unit energy consumption about vaporization-transportation was 1.946 kgce/t, while the corresponding natural gas flow of transportation was 690 t/h. Besides, the unit energy consumption decreased while natural gas flow of transportation increased, but the unit energy consumption would increase rapidly reversely at the moment of adding running equipments.