amashubhu acijile asontekile avunguzayo ajwayele ukusetshenziselwa imboni ye-petrochemical futhi afakwa kakhulu ezindaweni zokufudumeza izifudumezi ezibasiwe, ama-boilers okushisa imfucuza, ama-economizers, ama-air preheater, kanye nezishintshisi zokushisa ezibandakanya ukudluliselwa kokushisa kuketshezi olushisayo kuya oketshezini olubandayo ngokusebenzisa i-tube wall.