Different evaporation temperature based multistage organic Rankine cycle (ORC) power generation system

Abstract

The invention discloses a different evaporation temperature based multistage ORC power generation system. According to the system, n ORC sub-system evaporators are connected in series successively by a heat source water supply system through a hot water pipe. A cooling water supply system is connected in parallel with n ORC sub-system condensers. Working media are subjected to phase change into vapor in respective evaporators to push respective corresponding turbines to be expanded to do work, the liquid media are condensed and return to respective evaporators through respective corresponding work media, and accordingly, the multistage ORC power generation system is formed. The working media used by all the sub-systems are different, so that the different working media can work in optimal evaporation temperature states, and the whole system thermal efficiency is improved. Compared with conventional ORC systems, the heat transmission temperature difference in the evaporator is reduced, irreversible losses are reduced, and the temperature of a heat source discharge system is low, so that the low-grade energy use rate can be improved apparently, and the whole system economy is improved.

Description

technical field [0001] The invention belongs to thermal energy engineering, in particular to a multi-stage organic Rankine cycle thermoelectric conversion system in which different evaporation temperatures are selected according to the temperature of underground hot water. Background technique [0002] Energy shortage and environmental pollution have become one of the main problems restricting the sustainable development of human beings. At present, countries all over the world are trying to reduce their dependence on traditional fossil energy. Among them, for the utilization of geothermal energy as a low-grade energy source, the most commonly used method in the world is the Organic Rankine Cycle (ORC) power generation technology. This is a thermodynamic cycle using low-boiling point organic matter as the working medium. Its working principle is: the organic working medium absorbs heat from the heat source through the evaporator to produce a phase change, and the gaseous wo...

AI Technical Summary

Problems solved by technology

[0003] The problem with the traditional organic Rankine cycle is that all organic working fluids have an optimal evaporation temperature to maximize the system efficiency, but when the heat source is 150°C, it will cause the following two phenomena: (1) In order to absorb heat from the heat source More heat, the temperature setting of the heat source discharged from the evaporator is relatively low, which increases the heat transfer temperature difference in the evaporator, increases the irreversible loss, and reduces the evaporation temperature at the same time, so that the system does not work at the optimal evaporation temperature state; (2) Setting the discharge temperature of the heat source from the evaporator is relatively high, which can reduce the heat transfer temperature difference and reduce the irreversible loss (it can maintain an optimal evaporation temperature), but the discharge temperature of the heat source is relatively high, causing the heat source not to be fully utilized energy loss

Images