Organic Rankine cycle power generation system

Abstract

The invention discloses an organic Rankine cycle power generation system, which comprises a cycle power generation main circuit and an expander expansion gas regulating circuit; in the cycle power generation main circuit, the working medium outlet of the high-pressure evaporator is connected to the main gas inlet of the expander, and The outlet of the condenser is connected to the inlet of the condenser, the outlet of the condenser is connected to the inlet of the high-pressure working medium pump, the outlet of the high-pressure working medium pump is connected to the working medium inlet of the high-pressure evaporator, and the output of the expander is connected to the generator; In the expansion gas regulating circuit of the machine, the inlet of the low-pressure working medium pump is connected to the outlet of the condenser, the outlet of the low-pressure working medium pump is connected to the working medium inlet of the low-pressure evaporator, and the working medium outlet of the low-pressure evaporator is connected to the expansion gas of the expander The regulating port, the expanding gas regulating port of the expander is connected to the inlet of the first heat exchange pipeline of the regenerator, and the first heat exchange pipeline of the regenerator exits the inlet of the condenser. The invention can effectively prevent the problems of over-expansion and under-expansion of the expander.

Description

technical field [0001] The invention relates to the technical field of power generation systems, in particular to an organic Rankine cycle power generation system. Background technique [0002] Low-temperature thermal energy refers to relatively low-grade thermal energy. The temperature of low-temperature thermal energy is generally lower than 200°C. There are many types of these energy sources, including industrial waste heat, geothermal energy, biomass energy, ocean temperature difference energy, solar energy, and other renewable resources; The total amount is huge. According to statistics, 50% of the heat energy used by human beings is finally discharged directly in the form of low-grade waste heat. The Organic Rankine cycle system is the most common thermal cycle system for power generation that uses low-temperature heat energy below 200°C. [0003] figure 1 It is a schematic flow diagram of the existing organic Rankine cycle power generation system, refer to figure 1...

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Problems solved by technology

However, the existing organic Rankine cycle power generation system has the following technical problems in actual operation: the cold source usually uses natural resources, the annual temperature fluctuates in the range of -20°C to 35°C, the temperature fluctuates greatly, and the temperature of the heat source fluctuates Although it is small, it will also fluctuate with temperature changes. In the existing organic Rankine cycle power generation system, the internal volume ratio of the expander is usually fixed, and the design condition of the power generation system is usually based on the annual average working condition , the actual operating conditions of the system deviate from the design operating conditions for a long time. In the case of high summer temperatures, the condensing pressure increases, and the outlet back pressure of the expander increases, which is greater than the pressure in the expansion chamber of the expander. The outlet back pressure of the machine will reversely affect the pressure in the expansion chamber, increase the pressure in the expansion chamber, make the gas in the expander over-expand, and be compressed again during exhausting, resulting in a greatly reduced expansion efficiency; when the temperature is low in winter, condensation As the pressure decreases, the back pressure at the outlet of the expander decreases, which is less than the pressure in the expansion chamber of the expander. The back pressure at the outlet of the expander will reversely affect the pressure in the expansion chamber, reduce the pressure in the expansion chamber, and cause the gas in the expander to expand insufficiently, resulting in Under-expansion, secondary expansion occurs during exhaust, resulting in reduced expansion efficiency

In the existing organic Rankine cycle power generation system, the over-expansion and under-expansion problems caused by the expander reduce the average operating efficiency of the power generation system and reduce the average power generation. What is more serious is that the expanded gas will enter the gas-liquid Two-phase area, leading to major failures such as serious damage to the expander

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