CN-122015162-A - Closed steam-water loop of molten salt energy storage system for municipal heat supply and heat and mass transfer method

CN122015162ACN 122015162 ACN122015162 ACN 122015162ACN-122015162-A

Abstract

The invention relates to the field of energy technology and municipal heat supply, in particular to a closed steam-water loop and a heat and mass transfer method of a molten salt energy storage system for municipal heat supply, wherein a molten salt loop module is used for storing heat release energy, the steam-water loop module realizes indirect heat exchange through closed circulation, and a control module comprises a signal acquisition unit, a controller and an execution unit and is used for monitoring and adjusting. The heat and mass transfer method includes heat storage, cycle start, internal preheating, main heating, heat output, and condensate reflux. According to the invention, through a closed loop and cascade heat exchange design, the solidification risk of molten salt is effectively avoided by matching with low conventional mature commercial molten salt and waste heat recovery, the long-term operation reliability of the system is ensured, the municipal heat supply low-temperature working condition is adapted, the efficient consumption of off-peak electric energy and the stable heat energy transfer are realized, and the method has the greatest advantages that the conventional mature commercial molten salt can be adopted without depending on special low-freezing-point molten salt, so that the stable and efficient application of the conventional mature commercial molten salt in urban heat supply scenes is realized.

Inventors

MEI DEFANG
WANG SHOUJIN
DU HONGBO
LI LIUJUN
LIU YUBIN
WANG WEI

Assignees

北京京能热力股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260326

Claims (10)

1. Municipal administration is fused salt energy storage system closed soda return circuit for heat supply, its characterized in that includes: A molten salt loop module for storing and releasing thermal energy, having a molten salt outlet and a molten salt inlet; The steam-water loop module is provided with a molten salt inlet, a molten salt outlet, a heat supply network water inlet and a heat supply network water outlet; the heat supply network water inlet of the steam-water loop module is connected with a municipal heat supply water return pipe network, the heat supply network water outlet of the steam-water loop module is connected with a municipal heat supply water supply pipe network, and the heat energy of the steam-water loop module is firstly transferred to a closed circulation working medium serving as an intermediate medium, and then transferred to municipal heat supply network backwater by the working medium, so that indirect heat supply is realized; the control module is in communication connection with the molten salt loop module and the steam-water loop module, for monitoring and controlling the operating state thereof.
2. The municipal heat molten salt energy storage system closed soda loop of claim 1, wherein the molten salt loop module comprises: the cold salt tank and the hot salt tank are respectively used for storing low-temperature molten salt and high-temperature molten salt; the molten salt electric heater is connected between the cold salt tank and the hot salt tank and is used for heating molten salt; The cold salt pump is connected between the outlet of the cold salt tank and the inlet of the fused salt electric heater; The hot salt pump is connected between the hot salt tank outlet and the molten salt inlet of the steam-water loop module; the inlet of the cold salt tank forms a molten salt inlet of the molten salt loop module, and the outlet of the hot salt pump forms a molten salt outlet of the molten salt loop module.
3. The municipal heat molten salt energy storage system closed soda loop of claim 1, wherein the soda loop module comprises: The circulating water pump is used for driving the closed circulating working medium to flow; the working medium side inlet of the molten salt-steam-water heat exchanger is connected with the downstream of the outlet of the circulating water pump, the working medium side outlet of the molten salt-steam-water heat exchanger is connected with the upstream of the inlet of the circulating water pump, and the molten salt side inlet and the molten salt side outlet of the molten salt-steam-water heat exchanger respectively form a molten salt inlet and a molten salt outlet of the steam-water loop module; The heat regenerator is connected between a working medium side outlet of the molten salt-steam water heat exchanger and an inlet of the circulating water pump, and between an outlet of the circulating water pump and a working medium side inlet of the molten salt-steam water heat exchanger, and is used for carrying out heat exchange between internal working mediums; The heat supply heater is connected between the heat regenerator and the municipal heat supply network and used for releasing heat energy of the working medium to heat supply network water; the molten salt-steam-water heat exchanger and the heat supply heater are arranged in series, so that the closed circulation working substance can absorb heat of molten salt in the molten salt-steam-water heat exchanger first, and then release the heat to municipal heat supply network backwater in the heat supply heater.
4. The closed steam-water loop of the molten salt energy storage system for municipal heat supply according to claim 3, wherein the molten salt-steam-water heat exchanger is a three-stage heat exchanger and comprises a preheater, an evaporator and a superheater which are sequentially connected in series along the flow direction of a working medium and are used for transferring heat of molten salt to the working medium in a gradient manner, molten salt side inlets of the preheater, the evaporator and the superheater are connected in parallel to form a molten salt side inlet of the molten salt-steam-water heat exchanger together, and molten salt side outlets of the preheater, the evaporator and the superheater are connected in parallel to form a molten salt side outlet of the molten salt-steam-water heat exchanger together.
5. The closed type soda water loop of the molten salt energy storage system for municipal heat supply according to claim 3, wherein the soda water loop module further comprises a liquid storage tank and a water supplementing system, an outlet of the liquid storage tank is connected to an outlet pipeline of the circulating water pump, and an outlet of the water supplementing system is connected to an inlet of the liquid storage tank.
6. The closed steam-water circuit of the molten salt energy storage system for municipal heat supply according to claim 5, wherein the water replenishing system comprises a water feeding pump and a surge tank which are sequentially connected, and an inlet of the water feeding pump is connected with a deionized water machine.
7. The municipal heat-supplying molten salt energy storage system closed soda loop of claim 1, wherein the control module comprises: the signal acquisition unit comprises a temperature sensor and a pressure sensor which are arranged in the molten salt loop module and the steam-water loop module pipeline; The controller is in communication connection with the signal acquisition unit; The execution control unit comprises an electric tracing unit, a molten salt flow regulating valve and a steam-water flow regulating valve, wherein the electric tracing unit, the molten salt flow regulating valve and the steam-water flow regulating valve are connected with the controller, the electric tracing unit is arranged on a molten salt pipeline, the molten salt flow regulating valve is arranged on a molten salt outlet pipeline of the molten salt loop module, and the steam-water flow regulating valve is arranged on a working medium circulating pipeline of the steam-water loop module.
8. The closed soda water circuit of the molten salt energy storage system for municipal heat supply according to claim 2, wherein the molten salt in the molten salt circuit module has a solidifying point not lower than 100 ℃ and not higher than 142 ℃.
9. A method of heat mass transfer for a closed soda loop of a molten salt energy storage system for municipal heating, the method being for a closed soda loop of a molten salt energy storage system for municipal heating as claimed in any one of claims 1 to 8, comprising the steps of: S1, in a heat storage stage, in a valley electricity period, a control module starts a molten salt loop module to store heat, and converts electric energy into heat energy of high-temperature molten salt for storage; S2, in a cycle starting stage, when heat supply is needed, a control module starts a cycle power part in a steam-water loop module, establishes closed working medium cycle, and starts a molten salt release part in a molten salt loop module; S3, in an internal preheating stage, preheating a low-temperature working medium by using a high-temperature working medium through a heat regenerator in the steam-water loop module, and improving the temperature of the low-temperature working medium; s4, in a main heating stage, the preheated working medium absorbs heat of high-temperature molten salt from the molten salt loop module in the molten salt-steam-water heat exchanger and is converted into high-temperature working medium, and primary transfer of the heat of the molten salt to the working medium is completed; S5, in a heat supply output stage, the high-temperature working medium transfers heat to municipal heat supply network backwater in a heat supply heater to realize heat supply output, and the heat supply output stage is cooled to complete secondary transfer of heat of the working medium to heat supply network water; s6, in a condensation and reflux stage, the cooled working medium is refluxed to an inlet of the circulating power component to complete circulation; wherein, the fused salt after releasing heat in the fused salt-steam water heat exchanger returns to the fused salt loop module.
10. The method for heat and mass transfer of closed steam-water circuit of molten salt energy storage system for municipal heat supply according to claim 9, wherein in step S4, the working medium flows through the preheater, evaporator and superheater in the molten salt-steam-water heat exchanger in sequence, and is subjected to liquid phase heating, phase change evaporation and steam superheating process, and finally converted into high temperature steam.

Description

Closed steam-water loop of molten salt energy storage system for municipal heat supply and heat and mass transfer method Technical Field The invention relates to the field of energy technology and municipal heat supply, in particular to a closed steam-water loop of a molten salt energy storage system for municipal heat supply and a heat and mass transfer method. Background Under the dual promotion of energy transformation and low-carbon heat supply requirements, the fused salt energy storage technology gradually obtains wide attention in the fields of energy storage and heat supply by virtue of the outstanding characteristics of high heat storage density, good heat stability, long service life and the like. Municipal heat supply is the key field of guarantee folk life, is currently urgently needing clean, efficient energy storage heat supply scheme to the dual demand of adaptation renewable energy consumption and electric wire netting peak regulation, and the low ebb electricity energy storage advantage that fused salt energy storage system possessed just agrees with this demand, becomes the application technology that municipal heat supply field has very much potential. However, the application scenario of the existing molten salt energy storage system has obvious limitations, namely, the technical scheme is designed for high-temperature working conditions such as high-temperature industrial steam supply, power generation peak shaving and the like, and the low-temperature working conditions of municipal heat supply are not combined for targeted adaptation optimization, so that the application of the existing molten salt energy storage system in the municipal heat supply field faces a plurality of obstacles, and the most central problem is the contradiction between the molten salt solidification risk and the heat energy transfer stability. Specifically, the municipal heat supply network backwater temperature is obviously lower than the freezing point of common molten salt, and under the framework of the prior art, if the direct heat exchange or the simple indirect heat exchange design is adopted, the temperature of the molten salt is easily reduced to be lower than the freezing point in the heat exchange process, so that serious potential safety hazards such as pipeline blockage, equipment damage and the like are caused. Meanwhile, the heat exchange matching performance is insufficient, so that the heat energy transfer efficiency is low, the system is difficult to simultaneously consider the operation safety and the heat supply stability, and the core contradiction directly limits the large-scale popularization and application of the molten salt energy storage technology in the municipal heat supply field. In order to solve the contradiction, the prior art attempts to avoid the solidification risk of the molten salt by adopting a low-solidification-point molten salt mode, but the scheme has the obvious defects that the low-solidification-point molten salt is high in cost, poor in thermal stability, immature in engineering application technology and difficult to realize industrialization landing. On the other hand, although the conventional mature commercial molten salt has the advantages of low cost, good thermal stability, mature engineering application and the like, the conventional mature commercial molten salt cannot be directly applied to municipal heating scenes due to mismatching of the solidifying point and the municipal heating network backwater temperature, and the limitation further aggravates the popularization difficulty of the molten salt energy storage technology in the municipal heating field. Disclosure of Invention In order to make up for the defects, the invention provides a closed steam-water loop and a heat and mass transfer method of a molten salt energy storage system for municipal heat supply, and aims to solve the problems that when the conventional molten salt energy storage system is applied to municipal heat supply, molten salt solidification, pipeline blockage and equipment damage are easily caused because the return water temperature of a heat supply network is lower than the solidifying point of molten salt, the heat energy transfer efficiency is insufficient, and the system operation safety and the heat supply stability are difficult to be considered; The core improvement of the invention is that special low-freezing-point molten salt is not needed, and the stable application of the conventional mature commercial molten salt in municipal heat supply scenes is realized by optimizing loop design and heat exchange flow, so that the system cost is reduced, the engineering applicability is improved, and the problem of heat energy transfer stability is solved. In a first aspect, the present invention provides a technical solution, including: A molten salt loop module for storing and releasing thermal energy, having a molten salt outlet and a molten salt inlet; The steam-water loop