Method and device for solar energy and fossil fuel power station complementary circulation

Abstract

The invention discloses a method and a device for solar energy and fossil fuel power station complementary circulation and belongs to the filed of solar energy heat utilization. A combined circulation method formed by a fossil fuel thermodynamic system and a solar energy thermodynamic system is adopted, closed-type circulation with a heat storage device is adopted in the solar energy thermodynamic system, heat exchange between the solar energy thermodynamic system and boiler feed water of the fossil fuel thermodynamic system is carried out, the whole solar energy thermodynamic system is in paralleled connection with a boiler feed water heating system of the fossil fuel thermodynamic system, and the solar energy thermodynamic system is in serial connection with the boiler feed water heating system of the fossil fuel thermodynamic system. When solar energy radiation is low, working media enter into the heat storage device to be stored, and when the solar energy radiation can meet continuous operation demands of a boiler of the fossil fuel thermodynamic system, the working media enter into a heat exchange device to exchange heat with the boiler feed water; and when the solar energy radiation is too low to meet the lowest circulation demand, the working media can be reserved in the solar energy thermodynamic system. By means of the method and the device for the solar energy and fossil fuel power station complementary circulation, effective utilization time of the solar energy can be improved, solar energy thermal side efficiency is high, and safe and enforceable operation of a fossil fuel unit can be guaranteed.

Description

technical field [0001] The invention belongs to the field of solar thermal utilization. Background technique [0002] Due to the intermittent and uncertain characteristics of solar energy, power stations using solar thermal power generation technology usually need to use a combined cycle with fossil fuels or rely on heat storage to ensure the stable operation of the solar thermal power station. At present, the combined cycle of solar energy and fossil fuels is usually carried out in the following way: the solar thermal system is used as the primary heating equipment of the entire power station. The boiler continues to heat up, and then enters the steam turbine to generate power. When there is no sun, the solar energy is cut off and fossil fuels are used to generate electricity. This combined cycle method is usually called a complementary power generation method. In the actual operation of solar and fossil fuel power plants, there is a problem that the efficiency of the sola...

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Problems solved by technology

In the conventional complementary scheme, in order to ensure the rapid adjustment of fossil fuel units, they usually operate in complementary operation with oil or gas power plants. Due to the fluctuation and uncontrollability of solar energy, this design scheme is difficult to be operable in actual projects; due to the The fuel unit has certain restrictions on the added solar power. When the solar radiation is low, the power added to the fossil fuel unit cannot meet the minimum requirements, so that the solar side cannot be used. When the solar radiation exceeds the maximum added power, at this time The solar energy is wasted

At the same time, during operation, the conventional solar thermal system is completely cooled to resume operation. In order to avoid excessive thermal stress of the thick-walled thermal device, its heating speed is slow, which increases the start-up time of the solar thermal system and reduces the effective utilization time, which is not conducive to Improve solar energy utilization efficiency

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