Comprehensive Evaluation Research On Gas-fired Cogeneration Projects For Replacing The Coal-fired Units

Since the 1980s, environmental problems in China have become more and more serious, despite its economic surge. Although great achievements have been made in emission reduction of total amount of major pollutants in recent years, the current situation remains severe. Acid rain problem is still serious. Particulate pollution which is still the primary factor affecting the air quality in China has not been able to gain a substantial improvement yet. Pollutant shave gradually changed into the compound pollutants mixed by various substances, NOx becomes a new focus. Anyway, the overall pressure keeps rising. In recent years,our country tops the world on carbon emission, which leads to more and more international negotiations pressure. This shows that we should adjust our energy structure and development mode and speed up the alternative use of clean energy for going the way of "green" and "low-carbon". As one kind of clean and efficient energy which is of plentiful supply, natural gas gets strong support by the government in terms of power generation and cogeneration.The paper takes XH Gas-fired Cogeneration Project for replacing the coal-fired units as the research object. Firstly, it introduces the domestic and foreign research dynamic and progress on the project evaluation, expounds the theory of multi-index comprehensive evaluation, in traduces various kinds of evaluation methods, analyses and summarizes the main strengths and weaknesses of each method. On the basis of comparative analysis and combining with the practical situation of XH gas-fired cogeneration project, the FAHP Method is choose das the thesis’s theoretical support. Secondly, this thesis mainly focuses on the current national standard for atmospheric pollutant emission of coal plants、gas power plants and boilers. According to the standard and the actual situations of current power plants, this thesis carries on detailed comparison and analysis between gas and coal cogeneration units, between gas and coal boilers, thus obtains quantitative analysis and comparison for emission performance standard of both sides. Thirdly, this thesis makes a detailed introduction on the geographical conditions of XH area, the heat load, the practical situation of power network, load prediction, power planning, power balance, fuel supply, unit type selection and equipment fixing plan of the whole project, and illustrates the necessity and feasibility of the gas project.The above work could provide data support for subsequent research. Finally, based on the principles of building evaluation index, this thesis conducts an intensive case study of the project on the indicators of engineering technology, environmental protection, economic and social benefits and sustainable development. Upon using the method of AHP to determine the index weight, this thesis eventually builds up a comprehensive evaluation index system. Elaborating the fuzzy comprehensive evaluation theory, introducing the mathematical model of the fuzzy comprehensive evaluation, using the way of combining AHP with FCE, this thesis makes a multi-level fuzzy comprehensive evaluation of the subject project and analyses the evaluation results. The summary of the evaluation results puts forward concrete opinions and suggestions for the research topic and provides theoretical reference and practical guidance for later research in this field.