FLNG液化工艺系统放大效应及应用研究

摘要

Offshore natural gas liquefaction technology is the main research content of LNG-FPSO. Based on the bench and pilot test units, the corresponding small and pilot liquefaction process models were established. Firstly, the accuracy of the model was verified by comparing the experimental results and the simulation results. Then, the influence of feed gas parameters for the two different scale tests on the liquefaction process system was analyzed by HYSYS software. In view of not exactly the same of the small and pilot liquefaction processes, equipment selection, and the feed gas parameters, which will affect the accurate analysis of process scaling effect, through the bench-scale and pilot-scale experimental researches and the simulation of bench test, pilot test and target gas field liquefaction processes, a concept of net specific power consumption was proposed. The results show that the net specific power consumption can effectively reflect the performance changes of the process system with the scale of the device. With the increase of the scale of liquefaction, the net specific power is gradually reduced and the adaptability of the process is improved, confirming the feasibility of propane pre-cooling double nitrogen expander liquefaction process. Based on the numerical simulation, the net specific power consumption method can be used to forecast the net specific power consumption of different scale liquefaction processes, providing reference for the production and operation of the target gas field.%海上天然气液化工艺技术是LNG-FPSO的主要研究内容.以丙烷预冷双氮膨胀液化工艺的小试试验装置和中试试验装置为依托,建立了相应的小试、中试液化工艺模型.首先通过比较试验结果和模拟结果验证了模型的准确性,然后通过HYSYS软件数值模拟分析了两种规模原料气参数的变化对液化工艺系统的影响.鉴于小试、中试液化流程,设备选型,以及原料气参数的不完全相同会影响工艺放大效应的准确分析,通过对小试和中试装置的试验研究以及小试、中试及目标气田的液化工艺的模拟研究,提出净比功耗的概念.研究结果表明,净比功耗能够有效的反映工艺系统随装置规模放大过程的性能变化.随着液化规模的增大,净比功耗逐渐降低,工艺适应性更强,明确了丙烷预冷双氮膨胀液化工艺的可行性.在数值模拟基础上,采用净比功耗计算方法可以对不同规模液化流程的净比功耗进行预测,为目标气田的投产和运营提供参考.