Process Modeling And Safety Optimization For Low-concentration Oxygen-bearing Coalbed Methane Upgrading By Pressure Swing Adsorption

Oxygen-bearing coalbed methane with a low-concentration is a kind of unconventional methane resource,which can be widely found in the coal mining process.However,it is generally discharged directly in a large quantity or utilized in an inefficient level because of its difficulty to be recovered.This processing strategy will not only cause a huge environmental pollution and energy waste,but also bring about an increase in the potential risk of methane explosion.Therefore,there are potential dual valuations of economic and environment when employ a certain separation technology to achieve the efficient capture and utilization for the low-concentration oxygen-bearing coalbed methane.Compared with the traditional separation technologies such as cryogenic distillation,membrane separation and solvent absorption etc.,the pressure swing adsorption process has gradually shown a great competitive advantage in the fields of natural gas and biogas upgrading because of its strengths in the aspects of lower energy consumption,higher operational flexibility and higher industrialized level,etc.In view of the current situation of severe air pollution and resource waste caused by the large-scale emissions of the low-grade oxygen-bearing coalbed methane as well as the explosion risk problem which is difficult to avoid in the separation and purification process,we have developed a numerical simulation method in this paper to carry out a basic research work systematically for the safety and economy in the low-concentration oxygen-bearing coalbed methane upgrading process with a pressure swing adsorption technology.Therefore,a complete set of pressure swing adsorption model system was first developed in this paper and a three-bed six-step vacuum pressure swing adsorption process based on the modeling was then established to test the economical separation efficiency.The research results of process separation economics have shown that good process separation performances could be obtained by optimizing setting of the significant process manipulation parameters.Furthermore,in this paper,we have analyzed the safety of the whole separation process by applying the safety evaluation model based on the explosive triangle theory.And then we have obtained the dynamic distribution behaviors of the methane explosion zone distributions for the process system,which could provide a base for guiding the construction of the safe and explosion-suppressed process Finally,we have validated the good operation elasticity with safety and economic for process based on the inertial dilution and suppression by applying the safety evaluation model proposed in this paper.In this paper,the researches on the process of upgrading low-concentration oxygen-bearing coalbed methane can not only provide an economic optimization strategy for the this kind of separation and purification process,but also enable to provide the early theory guidance for the analysis,prediction and control of potential methane explosion hazard in the separation process.