An experimental investigation on hydrogen generation from in-situ gasification by pyrolysis

Abstract

Hydrogen can be generated from crude oil by in situ gasification (ISG); pyrolysis gasification is one of the main methods used for hydrogen production. In this study, thermogravimetric analysis with mass spectrometry (TG-MS) was used to study hydrogen generation from crude oil through pyrolysis gasification and was combined with equivalent characteristic spectrum analysis (ECSA) to obtain the amount of hydrogen and hydrogen generation efficiency (HGE). The results of thermogravimetry (TG) and derivative thermogravimetry (DTG) from heavy oil (HO) and light oil (LO) can be divided into three stages: drying, pyrolysis, and coking. HO generated hydrogen in all stages, whereas LO produced hydrogen only during the pyrolysis and coking stages. The results of quantitative analysis indicated that hydrogen was mainly generated in pyrolysis stage, where temperature interval was 358–521 °C. The Friedman, Ozawa-Flynn-Wall (OFW), and Kissinger-Akahira-Sunose (KAS) methods were used to calculate the kinetic parameters. The results suggested a raising trend of activation energies with the temperature increase, and the range of activation energies of hydrogen generation from HO and LO are 80.40–258.84 kJ/mol and 130.35–285.16 kJ/mol, respectively. The hydrogen generation behavior and kinetics of crude oil by pyrolysis gasification can provide certain parameters for ISG technology and assist in understanding the hydrogen generation process, which can promote the development of hydrogen generation through in-situ gasification.