CHARACTERISTICS OF HYDROPYROLYSIS OF PALAEOZOIC IMMATURE ALGAL KEROGEN

Through a study of hydropyrolytic process on oil shale samples colleced from Kukesait,Estonia,the characteristics of oil/gas generation from immature algal kerogen are approached in this paper.It is concluded that although it does show a quite high potential of hydrocarbon generation as seen by an analysis of thermal simulation experiments,the amount of immature oil yielded by algal kerogen is rather low.Its hy-dropyrolysis can well reproduce the process and characteristics of oil/gas evolution,indicating that it is difficult to form algal kerogen-derived oil/gas pools on a considerable scale.With a wider range of liquid window,in the mature stage,algal kerogen tends to generate oil rather than gas;moreover,the generated gas will be dominated by nonhydrocarbons.In the higher mature stage,a large quantity of light hydrocarbons and condensates is generated by the cracking of oil;and the early stage is characteristic of less gaseous hydrocarbons generated,while in the late stage,they would increase.The gaseous products are dominated by CO₂,and the content of methane is the highest among gaseous hydrocarbons,containing only a little amount of alkenes.The normal-isohydrocarbon composition is comprised of a very high content of nalkanes but less isohydrocarbons.Pyrolytic oil is predominating over the liquid products,with the peak oil generation around 300℃.The simulation time would affect the hydropyrolysis to certain extent,and a prolonged time would favourable for oil-cracking and increasing gaseous hydrocarbons.