低浓度煤矿瓦斯梯级发电系统模型

为了系统性地研究煤矿低浓度瓦斯发电及其余热回收利用技术的热力学性能,提高能源回收效率,通过对"煤矿抽采瓦斯梯级发电系统"进行研究,采用理论分析的方法,分别建立了瓦斯内燃机、余热锅炉、背压式汽轮机、ORC发电机组等主要设备及其他附属设备的热力学模型,并将其进行整合,联立方程组,通过顺序计算及迭代计算,给出"煤矿抽采瓦斯梯级发电系统"的最终计算结果.结果表明,瓦斯气所含化学能中,有22.3％ 直接由瓦斯内燃机转化为电能,余热利用系统可回收2.42％ 的电能,总发电热效率达到24.72％,增加10.85％,但瓦斯发电系统总体热效率仍然较低,有待进一步提高.本文所建立的理论计算模型可以清晰地表明现有瓦斯内燃发电系统的能量利用效率水平,以及所采用的余热利用系统对能量回收程度,该模型是对瓦斯发电及其余热利用系统所建立的完整的指标评价模型,对瓦斯发电及余热回收系统的优化和完善具有较强的指导意义.

Computational Model of Gas Cascade Power Generation System in Low Concentration Coal Mines

In order to systematically study the thermodynamic performance of low concentration gas power generation and waste heat recovery technology in coal mines and improve energy recovery efficiency, through the study of "coal mine gas extraction cascade power generation system", the thermodynamic equations of gas internal combustion engine, waste heat boiler, back pressure steam turbine, ORC generator set and other ancillary equipments are established respectively by theoretical analysis method. Then an integrated model which contains all equipments equations has been accomplished, through sequential calculation and iterative calculation, the final calculation results of "coal mine gas extraction cascade power generation system" are given. The results show that 22.3% of the chemical energy contained in gas is directly converted from gas internal combustion engine to electric energy. The waste heat utilization system can recover 2.42% of the electric energy. The total thermal efficiency of power generation reaches 24.72% and increases by 10.85%. However, the overall thermal efficiency of gas power generation system is still low and needs to be further improved. The theoretical calculation model established in this paper can clearly show the energy utilization efficiency level of the existing gas internal combustion power generation system and the degree of energy recovery of the waste heat utilization system. This model is a complete index evaluation model for the gas power generation and its waste heat utilization system, and has a strong guiding significance for the optimization and perfection of the gas power generation and waste heat recovery system.