Fashewar Shenhai-Hujja
Tafarkin kwalta ya fi dacewa da man fetur da dizal, wanda kayan shafa na musamman ya ƙunshi alkanes da cycloalkanes. Da bambanci, Kwalta ya kasance da cikakken hydrocarbons, mahadi masu ƙanshi, asphaltene, da resins.
Bincike ya nuna kamanceceniya a cikin sinadarai tsakanin kwalta da waɗannan makamashin, shaida ta kusancin rushewar sigogi. Wannan kamanceceniya yana ƙunshe da “kamar narke kamar” ka'ida, yana nuna cewa man fetur da dizal na iya shiga sosai kuma su narke kwalta.