| Energy resources are the reliable and indispensable element for human being. With the development of science and technology, human increasingly use all kinds of energy. China is in a critical period of rapid development and requires large amount of energy, so effectively using energy will be conducive to the harmonious development of society. But the industrial process can be not take full advantage of the energy, as a result it produces large amount of waste heat discharged to the natural environment, which causes environmental pollution. Recycling the waste heat is very important to reduce the waste of energy and protect environment.In view of recycling waste heat of circulating cooling water in power plants in China, the technological principle and thermal performance characteristics of absorption heat pump technology and the low vacuum heating technology are analyzed. And the comparative analysis of the two kinds of waste heat recovery technology has been completed. Based on practical engineering designing, the different engineering design scheme of waste heat recycling technology are reported, which will provide a technical reference to the research of the subsequent scholars. The main conclusions of this paper are as follows.By comparing the analysis of the thermal performance of extraction steam condition, low vacuum condition and heat pump condition, there is the result that the overall thermal performance of different heating conditions from good to bad in the order is heat pump condition, low vacuum condition and extraction steam condition with external heating load constant.For heat pump heating, the thermal performance of thermal power plant and heat supply system is being optimized with the increase of heat supply network water supply temperature. When the temperature is increased from 58℃ to 80℃, the amount of saving coal is increased by about one-third. When external heating quantity must be constant, back pressure of turbine is selected as far as possible low. The increase of the COP is conducive to thermal power plant and heat pump heating, which is the impact on the heat pump is especially obvious. When the COP increased from 1.5 to 2.0, the exergy loss of heating supply is reduced from 63.89 GJ/h to 0.74GJ/h, which is almost reduced to zero.For low vacuum heating, the comprehensive efficiency of thermal power plant is gradually increased with the increase of heat supply network water supply temperature, however, the exergy efficiency and exergy loss of heating supply system are gradually increased. Because the heat is recycled increased, and the heat exergy grade is also on the increasing. Low vacuum heating supply system is suitable for the bigger demand of external heat load.Through the comparison and analysis of off-design performance, there are results that when the heat supply network water supply temperature is the lower, namely external heating quantity is smaller, which should choose the absorption heat pump heating system. And when the heat supply network water supply temperature is the higher, namely external heating quantity is larger, which should choose low vacuum heating supply system. Through the comparison and analysis of design performance, there are results that the initial investment of heat pump heating scheme is bigger than low vacuum heat supply, and its high back pressure to increase impact power, which results in lower total revenue and longer investment payback period of low vacuum heat supply. Considering heat prices and coal prices, the point of its full-year earnings of heat pump heating scheme is better than that of low vacuum heating. Considering power prices, electricity price is higher, the more obvious advantages of heat pump heating scheme. |
PDF Full Text Request