Investigating pilot test of oil shale pyrolysis and oil and gas upgrading by water vapor injection

Abstract

The technology of oil shale pyrolysis by water vapor injection uses high-temperature steam as a heat carrier to heat oil shale. Water vapor not only plays the role of transferring and exchanging heat, but it also chemically reacts with organic matter and some oil and gas products, altering the generation characteristics of oil and gas products. In this paper, we developed a long reaction distance test system for oil shale pyrolysis by water vapor injection and obtained the effects of heat injection temperature and time on the quality of oil and gas products. First, the results showed that with increasing pyrolysis temperature, the hydrogen content in the gas components gradually increased and then tended to be stable. In the process of heat injection temperature, increasing from 330 °C to 475 °C, the hydrogen content increased from 1.05% to 66.64%. High hydrogen concentration was mainly due to the reaction of water vapor with carbon residues, water vapor conversion reactions, and steam gasification reactions of hydrocarbon gases. Then, for shale oil, when the injection temperature was higher than 500 °C, the content of light components in shale oil remained at high levels, but the content of heteroatomic compounds was very little and the quality of shale oil was good. Next, when the injection temperature was controlled to 555 °C and the pyrolysis time was increased from 0 h to 4 h, the hydrogen content in the gas products increased first and then decreased, but the heteroatomic contents in the shale oil products increased first and then decreased. When the pyrolysis time was 2.5 h, the hydrogen content peaked, reaching 87.6%. When the pyrolysis time was 2 h, the content of heteroatoms peaked and reached 8.22%. Overall, when the injection temperature was 555 °C and the injection time reached 3 h, the shale oil formed through oil shale cracking presented higher quality.