天然气发电混输管网热值波动规律研究

Fluctuation property of calorific value of mixing-flow pipeline during gas power generation

燃气电厂对热值波动以及热值变化率等气质均有较高要求,但供应燃气电厂的天然气气源种类越来越多,因此日趋复杂的气质（热值或沃泊指数）能否满足燃气电厂严苛的气质要求亟需进一步研究。为此,对2种不同热值气源替换的质换混输过程进行数值模拟,通过瞬时质扩散理论分析和模拟结果数据综合归纳,得出2种不同热值的天然气在质换混输过程中的气质变化规律和有效质扩散系数与雷诺数的关系式,并据此建立了预测质换混输管道沿程热值波动速率的方法,计算结果表明：对于一般输气速度,满足燃气电厂对热值变化率要求的输气距离为1-10km,流速越高所需距离越远。为工程设计提供理论和计算依据。

Gas power plants have a high requirement to the calorific value fluctuation and calorific value change rate, but the kinds of gas sources supplied to the gas power plants become more and more. So whether the increasingly complex gas quality （calorific value and wobbe index） can satisfy the strict requirement of gas power plants needs further research. Numerical simulation was focused on interchangemixing process of two gas sources with different calorific values replacement. Through instantaneous mass diffusion theory analysis and simulation results inductive research, the gas quality change properties and the formula of effective diffusion coefficient and Reynolds number were obtained. On this basis, the forecasting method for fluctuation rate of calorific value in interchange-mixing pipelines was established and the calculation results show that, for general gas transport speed, the distance meeting the requirement of gas power plants to heat value change rate is about 1 km to 10 km,and the higher the flow speed,the longer the required distance.