Low calorific value (LCV) gas is receiving widespread attention as a potential energy resource. In the process of oil shale in situ conversion, the heat injection link is crucial. By applying low calorific value gases to downhole combustion heaters with a catalytic combustion method, high temperature heat injection process can be realized. This method not only allows for the reuse of energy, but also saves on gas injection costs. However, the temperature of the exhaust gas produced by the combustion heater needs to be precisely controlled, since too low a temperature does not allow for effective heating and too high a temperature adversely affects the life of the catalyst and the heater. For this reason, in this study, the multivariate relationship between the injection flow rate, the injection duration and the heater structural parameters was established using mathematical calculations for a low calorific value gas consisting of methane, hydrogen and air. An analysis of the applicability resulted in a set of optimal design parameters: a combustion chamber radius of 0.025 m, a combustion chamber length of 1 m, an air flow rate of 0.006 m3/s, a hydrogen flow rate of 0.0001 m3/s, an injection duration of 3600 s, and a methane flow rate of 0.000544 to 0.000964 m3/s. The experimental results verified the validity of the calculations, providing theoretical support for the construction of the experimental platform and the optimization of the heater design. Furthermore, this study offers a valuable reference for the efficient utilization of low calorific value gases, thereby facilitating the development of this resource and the sustainable development of energy.
Shui et al. (2026) studied this question.