气田燃气式增压机烟气余热发电初探

为了提高气田增压机的能量利用效率、减少热排放污染,采用?分析方法,对烟气余热品质(做功能力)进行了评价。基于气田增压站地理位置普遍较偏僻、供电成本高、电力供应稳定性较差的实际情况,拟采用有机朗肯循环(ORC)对气田增压机烟气余热进行回收利用发电;根据现场测试的烟气参数,利用热力学模型、传热模型和系统经济性模型对烟气余热发电技术方案进行了优化。研究结果表明:①四冲程燃气式增压机能量利用率较低,输入能量仅有30%转化为有用功,约有33%的热量以烟气形式排出;②烟气值为342 kW,?百分比为34.8%,具有较高的品质,若被充分利用可使得增压机能量利用效率提高10%;③利用增压机烟气余热发电的功率和投资回收周期受工质种类、工质蒸发压力、冷凝温度和烟气换热后温度的影响较为明显,发电功率变化范围为10～80 kW,投资回收周期为3.0～6.5年;⑤对ORC工作参数进行优化后的余热发电功率为66.73～82.00 kW,可满足增压机工作的基本供电需求,投资回收周期为3.2～3.8年。结论认为,该研究成果可以为气田增压站烟气余热回收利用提供一项选择方案。

A preliminary discussion on the reutilization of flue gas waste heat from gas field boosters for power generation

In order to increase the energy utilization efficiency of boosters in gas fields and reduce its heat pollution, the quality of the flue gas waste heat (a work capacity) was evaluated by using the exergy analysis method. Considering that the boosters of gas fields are commonly located in remote areas with a high power supply cost and unstable power supply, it was planned to adopt the Organic Rankine Cycle (ORC) to reutilize the waste heat of the flue gas from the boosters of gas fields for power generation. Then, the power generation scheme of flue gas waste heat was optimized by using the thermodynamic model, the heat transfer model and the system economy model based on the flue gas parameters tested on site. And the following research results were obtained. First, the four-stroke gas booster is lower in energy utilization efficiency. Only 30% of the input energy is transformed into useful work, and about 33% of the heat is discharged in the form of flue gas. Second, the flue gas is of higher quality with an exergy value of 342 kW and an exergy percentage of 34.8%, so if it is utilized sufficiently, the energy utilization efficiency of boosters can be increased by 10%. Third, the power and payback period of power generation by using the flue gas waste heat of boosters are more affected by the type and evaporation pressure of working medium, the condensing temperature and the flue gas temperature after heat exchange. The generated power varies between 10 kW and 80 kW and the payback period is 3.0–6.5 years. Fourth, after ORC working parameters are optimized, the generated power of waste heat is in the range of 66.73–82.00 kW, which can satisfy the basic power supply demand of boosters, and the payback period is 3.2–3.8 years. In conclusion, the research results provide an optional scheme for the reutilization of flue gas waste heat from boosters of gas fields.