Economic Analysis Of The Unit Based On Thermal Economics Accounting Model

Facing the shortage of resources, low energy utilization, and the deteriorating ecological environment, energy-saving emission reduction of thermal power plant, the coal resources of the large users, has been a difficult task. The key to the optimization of the thermal system is the reasonable research method. Based on the exergy analysis, the thermal economics which is more comprehensive and accurate is developed. Both the economics and thermal economy of the unit are considered in this method, which makes it getting more and more attention.Several commonly used methods of thermal economics analysis are introduced, and the flaws in the process of establishing the supplementary equation of accounting model are pointed out. In this paper, the concept of exergy quality coefficient is proposed, and the thermal economics supplemental equations are improved. The THA condition of the N-330-17.75/540/540 unit is taken as an example. The thermal economic analysis is carried out, and the accuracy of the method is verified by comparing the traditional accounting model. The results show that the price of exergy from steam turbine is not equal to the price of steam which is from steam turbine inlet. Then the equipment exergy economic coefficient and the variation trend are also changed: compared with the results of original method, the equipment exergy economic coefficient of boiler is not changed,while equipment exergy economic coefficient of three pumps and generater are changed a little, this coefficient of high pressure and medium pressure cylinder is lower and low pressure cylinder is larger.Based on the energy quality coefficihent, a new supplthe variation trendementary equation is established. While calculating the exergy economic coefficient, the price of exergy loss is reenacted to reflect the operation status of the equipment and the energy saving potential more accurately. Taking N-300-16.67/537/537 thermal power generating unit as an example, thermal performance of the unit is analysed by using the energy quality coefficient method compared with that using exergy coefficient method. The results show that the variation trend of the equipment exergy economic coefficient is the same. The exergy economic coefficients of the deaerator and low-pressure heater 7change greatly, while exergy economic coefficients of other devices are very small. The results of coefficient method are acceptable and the accuracy of the method can beverified, while, compared to the method of energy quality coefficient, the method of exergy quality coefficient is more accurate.