Pob tawbhom pipeline lim yog cov kav dej thauj cov txheej txheem kom tshem tawm cov khoom impurities. Thaum cov kua ntws los ntawm lub lim, cov impurities raug lim tawm, uas tuaj yeem tiv thaiv kev ua haujlwm ntawm cov twj, compressors, cov twj paj nruag thiab lwm yam khoom siv. Thaum nws yog ib qho tsim nyog los ntxuav, tsuas yog tshem tawm cov lim lim cartridge, tshem tawm cov lim dej tawm thiab tom qab ntawd rov nruab nws. Covkhoom tuaj yeem yog cam khwb cia hlau, carbon steel thiab stainless hlau.