Igesi engajiyi evela esitsheni sokuqhekeka kukawoyela: ingxube ye-hydrogen, i-methane, i-ethane ne-ethylene, i-propane ne-propylene, ama-butane nama-butylene, ne-hydrogen sulfide encane. Ishiswa njengophethiloli, noma yenziwe uketshezi ihlukaniswe ngenxa yama-olefin ayo. Isha kalula kakhulu.