LNG工厂重烃脱除工艺方案应用研究

Research on the Application of Heavy Hydrocarbon Removal Process Transformation in LNG Plant

天然气因产地不同,气质组分、C5+重烃含量均不相同。在天然气液化过程中,重烃因其熔沸点低,若不脱除彻底,会在低温液化段使管路、阀门、设备出现冻堵现象,轻则造成经济损失,重则引发安全事故。以某小型LNG工厂为例,分析试车过程中出现换热器流道冻堵现象的原因,选取"重烃洗涤+低温冷脱"脱烃模式并应用于重烃脱除工艺技术改造。2015年末完成脱烃工艺技术改造,到2016年1月,累计开车超过3 000 h,管路阀门未出现冻堵现象,系统运行平稳。该研究对液化段重烃冻堵工艺改造有一定借鉴意义。

The proportion of C 5 ＋ heavy hydrocarbon and component of natural gas is different because of its region. Heavy hydrocarbons owing to the lower melting and boiling point than methane, if not removed completely, will lead to the frozen blocking phenomenon of the pipel ine, valve and equipment in the natural gas liquefaction process, which will result in the economic losses or safety accidents. Take the heavy hydrocarbon removal process of a small LNG plants as an example in this paper. The causes of heavy hydrocarbon ice blockage in the heat exchanger are analyzed. The removal mode of ^ Heavy hydrocarbon washing ＆ Low temperature cold desorption” is selected and applied in the heavy hydrocarbon removal process transformation. The renovation was finished in the end of 2015. Up to Jan. 2016, working hours of this LNG plant have totaled up to about 3 000 h and frozen blocking has never happened. This new system runs extremely stably. The research has certain guiding significance for the transformation of heavy hydrocarbon ice blockage in liquefaction process.