Steam generation system for solar photo-thermal power station and operation method of steam generation system

Abstract

The invention relates to a steam generation system for a solar photo-thermal power station and an operation method of the steam generation system. The steam generation system provides a water workingmedium through a water supply unit, and the steam generation system comprises a preheater, a venturi nozzle, an evaporator, a steam pocket and a starting unit. According to the steam generation systemand the operation method of the steam generation system, the feed water kinetic energy is utilized, meanwhile, the venturi nozzle principle is utilized, on one hand, the circulation volume of the steam-water medium between the evaporator and the steam pocket is promoted through the accelerated mixing function of the venturi nozzle, and the structure is between natural circulation and forced circulation; and on the other hand, when the feed water temperature is lower than the molten salt freezing point, the feed water can be mixed with steam water in a steam pocket downcomer through the venturi nozzle, and finally the temperature of the feed water entering the evaporator is increased. According to the steam generation system and the operation method of the steam generation system, the investment of a forced circulation pump is saved, the reliability of system operation is improved, and meanwhile the auxiliary power is saved.

Description

technical field [0001] The invention relates to the technical field of solar thermal power generation, in particular to a steam generation system and an operating method thereof for a solar thermal power station. Background technique [0002] There are various ways to utilize solar energy, including wind energy, tidal energy, photovoltaic power generation, solar thermal power generation and other technical categories. Solar thermal power generation can be divided into trough type, tower type, butterfly type and linear Fresnel according to the structure of concentrating mirror and heat collector. [0003] In order for solar thermal technology to stand out among many power generation technologies and ultimately achieve a major breakthrough in cost, at least two problems need to be solved, one is the reliability of the equipment, and the other is to optimize the system structure through process improvement. Reduce equipment investment. [0004] Whether it is a solar-thermal p...

AI Technical Summary

Problems solved by technology

At present, for the steam generation system of subcritical and supercritical units, because the traditional natural circulation scheme is difficult to achieve efficient steam generation, the forced circulation scheme is adopted in the traditional design. This scheme needs to use a forced circulation pump as the steam drum and evaporation However, due to the use of the forced circulation pump, there are two problems: one of the problems is that the cost of the forced circulation pump is higher than that of the general water pump due to its high operating temperature and high operating pressure. The high expenditure affects the urgent need to reduce costs in the solar thermal power generation industry; the second problem is that since the forced circulation pump is a moving part, compared with the natural circulation scheme, it greatly increases the failure rate and operation risk of the system operation. From the current first batch The operation of the steam generation system of the solar thermal power generation demonstration project also proves the seriousness of this problem

[0005] In addition, due to the particularity of the molten salt heat exchanger, when the temperature of the water working medium in the molten salt heat exchanger is lower than the freezing point of the molten salt working medium, it will cause the molten salt to solidify and cause a production shutdown accident. Therefore, to improve the molten salt heat exchange The temperature of the water working medium at the inlet of the boiler is particularly important. The current solution is generally to add a group of heat exchangers in front of the molten salt heat exchanger to increase the temperature of the feed water. There may be a problem that the temperature of the feed water is lower than the freezing point of the molten salt working fluid

[0006] Therefore, it is necessary to find a safe solution that can not only properly solve the problem that natural circulation cannot meet the demand for steam generation, but also avoid the increase in cost and failure rate caused by the use of forced circulation pumps, and at the same time ensure that the inlet water of the molten salt heat exchanger The temperature of the working fluid is higher than the freezing point of the molten salt working fluid

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