Ammonia-water mixed working medium thermodynamic cycle system for low-grade thermal power generation

Abstract

The invention provides an ammonia-water mixed working medium thermodynamic cycle system for low-grade thermal power generation. The system comprises an absorption condenser, an ammonia-rich solution pipeline, a solution pump, a heat regenerator, a heat source fluid runner, an evaporator, a gas-liquid separator, a superheater, an ammonia-water mixed steam pipeline, a steam turbine, a main power generator, a cooling water heat exchanger, an absorption liquid pipeline, a water turbine, an auxiliary power generator, a back pressure adjusting valve and an absorption liquid sprayer. According to thesystem, the chemical absorption mode is adopted to promote condensation of ammonia-water mixed steam, partial ammonia gas is enabled to react with an absorbent to stably exist in the liquid phase inthe form of ammonia ions or complex ammonia, the concentration of the ammonia in a solution can be remarkably improved under the condition that partial pressure of the ammonia gas in the gas phase isnot increased, so that condensation of the ammonia-water mixed steam can be realized under the low backpressure. The solution is heated in the evaporator, along with continuous increasing of the temperature, the hydrated ammonia, the ammonia ions and the complexing ammonia are resolved to release the ammonia gas, and the absorbent is regenerated while only the ammonia and water in volatile components are evaporated in a temperature-changing mode.

Description

technical field [0001] The invention relates to a thermodynamic cycle with ammonia-water mixed working medium, more precisely, it adopts a chemical absorption method to make the ammonia-water mixed steam condense at normal temperature with a relatively low back pressure by using a chemical absorption method. Cycle, mainly used for low-grade thermal power generation. Background technique [0002] Compared with the single working fluid Rankine cycle of constant temperature evaporation, the variable temperature evaporation process of zeotropic mixed working fluid achieves a better heat transfer match with the sensible heat source, reduces the irreversible loss in the heat transfer process, and thus obtains higher thermal efficiency . Some studies have shown that the thermal efficiency of the ammonia working medium Rankine cycle can reach 1.05 to 1.25 times that of the steam Rankine cycle {Bo Hanliang, Ma Changwen, Wu Shaorong. Ammonia working medium Rankine cycle. Journal of T...

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Problems solved by technology

[0004] Although the Kalina cycle has a greater improvement in thermal efficiency compared with the Rankine cycle, its system is much more complex than the Rankine cycle, which has a greater negative impact on its economy

The Kalina cycle still has a lot of room for improvement in the following aspects: (1) There are many links in the distillation subsystem, resulting in a large exergy loss; (2) The heat transfer area is much higher than that of the Rankine cycle, and the metal consumption is higher; (3) The condensing back pressure of mixed steam is high, which limits the improvement of thermal efficiency

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