Direct-expansion solar thermal power generation system based on cascade Rankine cycle

Abstract

The invention belongs to the technical field of thermal power generation and in particular relates to a direct-expansion solar thermal power generation system based on a cascade Rankine cycle. The direct-expansion solar thermal power generation system based on the cascade Rankine cycle comprises a parabolic trough collector array and the cascade Rankine cycle; the cascade Rankine cycle comprises a steam Rankine cycle located at the top and an organic Rankine cycle located at the bottom. Compared with the prior art, the direct-expansion solar thermal power generation system based on the cascade Rankine cycle has the following advantages at the same time: ability of well running at low environmental temperatures, higher power generation efficiency, suitability for small-scale distributed construction, extremely low technical requirements on heat collection and heat accumulation, and high stability and high reliability.

Description

Technical field [0001] The invention belongs to the technical field of thermal power generation, and in particular relates to a direct expansion solar thermal power generation system based on a cascade Rankine cycle. Background technique [0002] Thermal power generation technology is one of the important ways to use solar energy. According to the data of the Concentrated Solar Power Market Research Center, the installed capacity of the global solar power system (SEGS) increased by 32% in 2014 to 4533MW. Among all commercial solar power generation systems, the parabolic trough collector (PTC)-based system is the most mature and mainstream, accounting for approximately 90% of the installed capacity of all operating and under construction power stations. [0003] Usually the parabolic trough thermal power generation system (PTC-SEGS) uses a turboexpander-based steam Rankine cycle. It has the following drawbacks: First, in order to avoid condensation during expansion, only superheate...

AI Technical Summary

Problems solved by technology

[0003] Usually, the parabolic trough thermal power generation system (PTC-SEGS) adopts the steam Rankine cycle based on the turbo expander, which has the following defects: First, in order to avoid the condensation of water vapor during expansion, only superheated steam (close to or higher than 673K) can enter the turbo

Large concentration ratio requires high-precision tracking system, frequent maintenance, repair and replacement of moving parts and gears

Third, storing high-grade heat is difficult

But this design is very complicated (especially the fit of the axis)

The feasibility of connecting screw expanders in series has not yet been confirmed

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