Industrial waste heat recovery and heating system based on heat pump

Abstract

The utility model discloses an industrial waste heat recovery and heating system based on a heat pump, and belongs to the technical field of waste heat and waste energy recovery and utilization. Comprising a cooling circulation water pipeline, a plate heat exchanger, an evaporator, a condenser and a heating network water pipeline, the two ends of the cooling circulation water pipeline are communicated with a heat medium inlet and outlet of the plate heat exchanger respectively, and a cold medium inlet and outlet of the plate heat exchanger are communicated with a cooling medium inlet and outlet of the evaporator through softened water pipelines respectively; a refrigerant outlet of the evaporator is communicated with an inlet of the centrifugal compressor, an outlet of the centrifugal compressor is communicated with a refrigerant inlet of the condenser, a refrigerant outlet of the condenser is communicated with a refrigerant inlet of the evaporator through a pipeline, and the two ends of the heating network water pipeline are communicated with a cooling medium inlet and a cooling medium outlet of the condenser respectively. According to the utility model, efficient recovery of waste heat of cooling circulating water is realized, and the waste heat is used for heating a heat supply network, so that excessive heating and leakage of steam are reduced, the energy utilization efficiency is improved, and energy waste is reduced.

Description

Technical Field

[0001] This utility model relates to the field of waste heat and energy recovery and utilization technology in the non-ferrous metal smelting industry, specifically to an industrial waste heat recovery and heating system based on a heat pump. Background Technology

[0002] Currently, energy conservation and improving energy efficiency are the most effective and important ways to reduce carbon emissions in the wet smelting industry. Domestic smelting enterprises are striving to improve the efficiency of waste heat and energy recovery and utilization, strengthen the balance and optimization of various energy media, significantly improve energy conversion efficiency, and reduce energy loss, so as to achieve high-energy high-use, low-energy low-use, and quality-unreduced use, and make full use of secondary energy.

[0003] With increasing energy demand and stricter environmental protection requirements, the recovery and utilization of industrial waste heat and energy has become an important means of energy conservation and emission reduction. Many industrial production processes generate a large amount of waste heat, which, if directly discharged, not only wastes energy but also causes thermal pollution to the environment. Therefore, developing efficient waste heat and energy recovery and utilization systems is of great significance.

[0004] Traditional waste heat recovery technologies typically employ simple heat exchangers, which are inefficient and fail to fully utilize low-grade waste heat. In recent years, heat pump technology has gained attention for its ability to upgrade low-grade heat energy to high-grade heat energy. However, there is still room for optimization in the integration of heat pump systems with industrial cooling systems, particularly in the synergistic utilization of cooling circulating water and heating networks. Utility Model Content

[0005] The purpose of this invention is to provide an industrial waste heat recovery and heating system based on a heat pump. By combining components such as a plate heat exchanger, evaporator, and condenser, it achieves efficient recovery of waste heat from cooling circulating water and applies it to the heating network. This changes the heating method from steam heating to hot water heating, reducing excessive steam heating and leaks, improving energy utilization efficiency, and reducing energy waste. This addresses the problems mentioned in the background art.

[0006] The technical solution adopted in this utility model is as follows:

[0007] An industrial waste heat recovery and heating system based on a heat pump includes a cooling circulating water pipeline, a plate heat exchanger, an evaporator, a condenser, and a heating network water pipeline. The two ends of the cooling circulating water pipeline are respectively connected to the inlet and outlet of the heat medium of the plate heat exchanger. The inlet and outlet of the cold medium of the plate heat exchanger are respectively connected to the inlet and outlet of the cooling medium of the evaporator via softened water pipelines. The refrigerant outlet of the evaporator is connected to the inlet of a centrifugal compressor. The outlet of the centrifugal compressor is connected to the refrigerant inlet of the condenser. The refrigerant outlet of the condenser is connected to the refrigerant inlet of the evaporator via a pipeline. The two ends of the heating network water pipeline are respectively connected to the inlet and outlet of the cooling medium of the condenser.

[0008] The cooling water temperature at the inlet of the plate heat exchanger is 35°C, and the cooling water temperature at the outlet of the plate heat exchanger is 30°C.

[0009] The softened water temperature at the outlet of the plate heat exchanger is 33°C, and the softened water temperature at the outlet of the evaporator is 28°C.

[0010] The temperature of the softened water for heating at the cooling medium outlet of the condenser is 70°C, and the temperature of the softened water for heating at the cooling medium inlet of the condenser is 50°C.

[0011] The refrigerant in the evaporator is Freon.

[0012] A throttling orifice plate is installed on the pipe between the refrigerant outlet of the condenser and the refrigerant inlet of the evaporator.

[0013] Temperature sensors for detecting the temperature of softened water for heating are installed at both the inlet and outlet of the cooling medium of the condenser, and the temperature sensors are electrically connected to the guide vane motor of the centrifugal compressor.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0015] This utility model changes the heating method from steam heating to a closed-loop circulating hot water heating system, reducing water waste and heat loss caused by steam leakage and direct discharge of condensate, ensuring the heating needs of the factory area, and reducing heating costs, saving 11.36 million yuan in heating costs annually. By setting up evaporators, condensers, and centrifugal compressors, the heat of the circulating cooling water can be reused, significantly reducing heating energy consumption and greatly increasing the capacity reserve of the heating system. This effectively improves the recycling level of waste hot water in industrial enterprises, reduces carbon emissions, and reduces corresponding air pollutant emissions, resulting in good "dual carbon" emission reduction benefits.

[0016] This invention extracts heat from circulating water for heating in the factory area, effectively reducing carbon emissions, lowering heating costs, reducing water and heat waste caused by direct discharge of condensate, reducing operating costs in the non-ferrous metal smelting industry, achieving the expected effect of "waste heat utilization and green heating", optimizing the energy system, improving resource utilization efficiency, and providing solid support for implementing the "dual carbon" strategic goals and the application of low-carbon process technologies.

[0017] This invention is highly adaptable to actual production, safe and reliable in operation, and has advantages such as high COP value, small footprint, and low failure rate. It is not only applicable to non-ferrous metal smelting systems, but can also be widely applied to the recovery and utilization of waste heat and energy in industries such as hydropower and chemicals. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0021] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] Example 1

[0023] like Figure 1 This embodiment provides an industrial waste heat recovery and heating system based on a heat pump, including a cooling circulating water pipeline, a plate heat exchanger, an evaporator, a condenser, and a heating network water pipeline. The two ends of the cooling circulating water pipeline are respectively connected to the inlet and outlet of the heat medium of the plate heat exchanger. The inlet and outlet of the cold medium of the plate heat exchanger are respectively connected to the inlet and outlet of the cooling medium of the evaporator through softened water pipelines. The refrigerant outlet of the evaporator is connected to the inlet of the centrifugal compressor. The outlet of the centrifugal compressor is connected to the refrigerant inlet of the condenser. The refrigerant outlet of the condenser is connected to the refrigerant inlet of the evaporator through a pipeline. The two ends of the heating network water pipeline are respectively connected to the inlet and outlet of the cooling medium of the condenser.

[0024] The cooling water temperature at the inlet of the plate heat exchanger is 35°C, and the cooling water temperature at the outlet of the plate heat exchanger is 30°C.

[0025] The softened water temperature at the outlet of the plate heat exchanger is 33°C, and the softened water temperature at the outlet of the evaporator is 28°C.

[0026] The temperature of the softened water for heating at the cooling medium outlet of the condenser is 70°C, and the temperature of the softened water for heating at the cooling medium inlet of the condenser is 50°C.

[0027] The refrigerant in the evaporator is Freon.

[0028] An expansion valve and a throttling orifice plate are installed on the pipe between the refrigerant outlet of the condenser and the refrigerant inlet of the evaporator.

[0029] Temperature sensors for detecting the temperature of softened water for heating are installed at both the inlet and outlet of the cooling medium of the condenser, and the temperature sensors are electrically connected to the guide vane motor of the centrifugal compressor.

[0030] This invention primarily controls operation by opening and closing the suction guide vanes on the inlet side of the centrifugal compressor. Based on signals from the outlet temperature sensor of the softened heating water (warm water), the compressor's guide vane motor is driven to maintain a constant outlet temperature for the softened heating water. When the load on the softened heating water decreases, if the inlet temperature of the warm water exceeds the set value, the unit will automatically shut down (temporary shutdown). Once the inlet temperature of the warm water drops and exceeds the set value, it will automatically restart (a light-load shutdown function via the inlet temperature sensor).

[0031] During winter heating, the cooling water in the cooling circulating water pipeline is also called heat source water, which provides a low-temperature heat source to the centrifugal chiller unit via a heat source water pump.

[0032] The main working mechanism of this utility model is a high-temperature centrifugal heat pump unit consisting of an evaporator, a condenser, and a centrifugal compressor. Through the phase change (liquid-gas-liquid) of the refrigerant inside the unit, the liquid refrigerant absorbs the low-temperature heat source of the circulating water cooled by sulfuric acid and turns into a gaseous state. This gaseous state is then heated by the compressor to produce high-temperature hot water for heating. The evaporator in the centrifugal heat pump unit uses Freon as the refrigerant, and its heating principle belongs to the refrigerant vapor compression cycle. Specifically, the evaporator absorbs low-grade heat from the heat source, the compressor increases the refrigerant vapor pressure, and the condenser discharges the heat to the hot water system.

[0033] In a centrifugal heat pump, the centrifugal compressor draws in refrigerant gas that has absorbed heat and evaporated in the evaporator. This gas is then compressed by a high-speed rotating impeller, becoming a high-pressure, high-temperature refrigerant gas that is more prone to condensation (liquefaction). The centrifugal compressor is the core component of the centrifugal heat pump; it accelerates the refrigerant gas and generates pressure through the high-speed rotating impeller. The refrigerant gas is drawn in through the compressor inlet, accelerated by the impeller, resulting in increased pressure and velocity, and finally discharged through the outlet. This process follows the laws of conservation of energy and momentum.

[0034] In the evaporator, the refrigerant absorbs low-grade heat from a heat source, and its pressure is then increased in the compressor. The heat is then discharged into the hot water system, while a throttling device (orifice plate) controls the refrigerant flow rate. In this way, the system can extract heat from low-temperature heat sources (such as air, river water, seawater, municipal sewage, etc.) and transfer it to a higher-temperature medium. The evaporator side is connected to circulating cooling water supply and return pipes.

[0035] Condenser: The high-pressure refrigerant gas is cooled and condensed (liquefied) by the cooling water flowing from the cooling tower. It is connected to a heating return water pipe on the side, with a designed hot water return temperature of 50℃ and a supply water temperature of 70℃.

[0036] The system circulation of this utility model is divided into four parts: cooling water circulation system circulation, plate heat exchanger system circulation, heat pump unit internal circulation, and heating network water circulation.

[0037] Cooling water circulation system: 35℃ cooling water enters the plate heat exchanger to cool down to 30℃ and then returns to the cooling water circulation system.

[0038] Plate heat exchanger system circulation: Softened water in the plate heat exchanger absorbs heat from the circulating water and is heated to 33°C before being sent to the evaporator. After the evaporator extracts 5°C of heat, the softened water at 28°C continues to absorb heat from the circulating water, repeating the above cycle. According to the circulating water quality report, the circulating water in the smelting industry has high hardness, chloride ion, and sulfate ion content. Therefore, installing a plate heat exchanger system can effectively prevent the circulating water quality from corroding and scaling the heat transfer tubes in the evaporator. Moreover, the plate heat exchanger is easier to maintain than the heat pump unit.

[0039] Internal circulation of the heat pump unit: In the heat pump evaporator, the liquid refrigerant absorbs heat from the softened water in the plate heat exchanger and evaporates. After the refrigerant changes from liquid to gas, it is drawn into the compressor. Relying on the high-speed rotation of the compressor impeller, the pressure and temperature of the gaseous refrigerant are increased. Then, it passes through components such as the diffuser, bend, and reflux device and is discharged into the condenser. The softened heating water flowing in the condenser absorbs the heat of the refrigerant vapor, raising the temperature of the softened heating water to 70°C, which is then supplied to the heating system. The refrigerant is condensed into liquid, and the liquid refrigerant returns to the evaporator after passing through the orifice plate, repeating the above cycle again.

[0040] Heating network water pipeline system circulation: In the heating system, the circulating softened water enters the condenser of the heat pump unit to absorb heat and rise to 70°C before returning to the heating user side to provide heating. After heating, the 50°C hot water re-enters the condenser of the heat pump unit to repeat the above cycle.

[0041] This invention can continuously expand the heating load and connect to more heating areas without adding new heat sources. It has a wide range of applications, extracting low-grade heat from soil, groundwater, surface water, urban sewage, and low-temperature waste heat from industrial circulating water, transferring the heat to the interior of buildings to achieve heating and domestic hot water production. The centrifugal water source heat pump unit is a mature technology, safe and reliable in operation, and has advantages such as high COP value, small footprint, and low failure rate.

Claims

1. A heat pump based industrial waste heat recovery and heating system, characterized in that, The cooling circulating water pipeline, the plate heat exchanger, the evaporator, the condenser and the heating network water pipeline are connected, two ends of the cooling circulating water pipeline are communicated on the hot medium inlet and outlet of the plate heat exchanger, the cold medium inlet and outlet of the plate heat exchanger are communicated with the cooling medium inlet and outlet of the evaporator through the softened water pipeline, the refrigerant outlet of the evaporator is communicated with the inlet of the centrifugal compressor, the outlet of the centrifugal compressor is communicated with the refrigerant inlet of the condenser, the refrigerant outlet of the condenser is communicated with the refrigerant inlet of the evaporator through the pipeline, and two ends of the heating network water pipeline are communicated on the cooling medium inlet and outlet of the condenser.

2. A heat pump based industrial waste heat recovery and heating system according to claim 1, characterized in that: The cooling circulating water temperature at the hot medium inlet of the plate heat exchanger is 35 ℃, and the cooling circulating water temperature at the hot medium outlet of the plate heat exchanger is 30 ℃.

3. A heat pump based industrial waste heat recovery and heating system according to claim 2, characterized in that: The softened water temperature at the cold medium outlet of the plate heat exchanger is 33 ℃, and the softened water temperature at the cooling medium outlet of the evaporator is 28 ℃.

4. A heat pump based industrial waste heat recovery and heating system according to claim 3, characterized in that: The temperature of the heating softened water at the cooling medium outlet of the condenser is 70 ℃, and the temperature of the heating softened water at the cooling medium inlet of the condenser is 50 ℃.

5. A heat pump based industrial waste heat recovery and heating system according to claim 1, characterized in that: The refrigerant in the evaporator is freon.

6. A heat pump based industrial waste heat recovery and heating system according to claim 1, characterized in that: A throttling orifice is arranged on the pipeline between the refrigerant outlet of the condenser and the refrigerant inlet of the evaporator.

7. A heat pump based industrial waste heat recovery and heating system according to claim 1, characterized in that: Temperature sensors for detecting the temperature of the heating softened water are arranged at the cooling medium inlet and outlet of the condenser, and the temperature sensors are electrically connected with the guide vane motor of the centrifugal compressor.

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