A novel cogeneration system and method based on dual-unit operation mode

Abstract

The invention discloses a new type of combined heat and power system based on the operation mode of two sets; the system mainly includes two parts: a power generation system and a heat supply system, and one of the generating sets can be transformed so that it can provide partial low-parameter extraction steam , and then use all the exhaust steam of the medium-pressure steam turbine of another generator set for the high-parameter steam extraction required by the heating system. Through the efficient coupling between the dual-unit power generation system and the heating system, the high parameters required by the heating system can be saved The amount of steam extracted can improve the thermal economy of the combined heat and power system. At the same time, the system uses an absorption heat exchanger to realize the heat exchange process between the primary heating network water and the secondary heating network water, and uses an absorption heat pump to efficiently recover the low-temperature waste heat of the system. Based on the principle of cascade utilization of energy, the invention combines the advantages of high back pressure heating technology, absorption heat pump technology and absorption heat exchange technology on the basis of dual unit operation mode, and has good innovation and practicality.

Description

technical field [0001] The invention relates to a novel heat and power cogeneration system and method based on a double-unit operation mode, and belongs to the technical field of energy saving and emission reduction. Background technique [0002] Combined heat and power (CHP) is a system based on the concept of cascade utilization of energy, which integrates power generation and heating processes, with the purpose of improving energy utilization efficiency and reducing emissions of carbides and harmful gases. With the increasing heating demand of residents, coal-fired power plants are mostly developing in the direction of combined heat and power in order to reduce the coal consumption of power supply. In the past, many areas in northern my country adopted the method of burning scattered coal for heating in winter, which was inefficient and polluted. The combined heat and power unit can be used for centralized heating and realize efficient and clean use of energy. Therefore, ...

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Problems solved by technology

[0004] However, there are still many problems in the conventional cogeneration method: (1) There are huge heat transfer temperature differences between the exhaust steam of the medium-pressure steam turbine and the water in the primary heating network, and between the water in the primary heating network and the water in the secondary heating network, resulting in There is a huge loss of usable energy in the thermal process; (2) the low-temperature waste heat released by the condenser has a large loss, and the energy utilization efficiency of the unit is low; (3) the heat supply method of the medium-pressure steam turbine greatly reduces the steam output of the low-pressure steam turbine. The flow rate makes the operation of the low-pressure turbine seriously deviate from the design condition. When the inlet flow area of ​​the low-pressure turbine and the speed of the turbine remain constant, the pressure of the steam entering the low-pressure turbine decreases with the decrease of the flow rate, resulting in a huge additional power loss.

[0005] In order to improve the thermal economy of combined heat and power units, many scholars have proposed optimization schemes, such as high back pressure heating technology, absorption heat pump technology and absorption heat exchange technology, etc., but the effective combination of these optimization schemes has not been reported. In addition, my country's power plants often adopt the operation mode of dual units in terms of construction scale, such as 2*350MW, 2*660MW, 2*1000MW, etc. If the combined heat and power system can be combined with the operation mode of dual units, it will inevitably achieve further progress. energy saving effect

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