CN101187509A - Integral injection type low temperature waste heat power generation refrigeration device - Google Patents

Abstract

An integral injection type low-temperature waste heat power generation and refrigeration device, the invention includes: a working medium pump, a waste heat heat exchanger, a turbine generator, an ejector, a condenser, a liquid storage tank, a three-way valve, a throttle valve, and an evaporator . These components are connected in sequence, with solar energy, geothermal energy, biomass energy or various low-temperature waste heat as the system heat source, groundwater, lake water, river water or sea water as the cold source, and low-boiling-point organic matter with excellent environmental performance as the working medium to form a closed cycle. system. The invention combines the organic Rankine cycle with the ejector refrigeration cycle through an ejector, and continuously outputs electric energy and cooling capacity to users while low-grade heat energy is continuously recycled, thereby realizing power generation and refrigeration using low-temperature waste heat. The invention complies with the principle of cascade utilization of energy, thereby greatly improving the comprehensive utilization rate of energy.

Description

Integral injection type low temperature waste heat power generation refrigeration device

technical field

The invention relates to a device in the technical field of refrigeration, in particular to an integral injection type low-temperature waste heat power generation refrigeration device.

Background technique

Statistics show that the total amount of low-temperature waste heat accounts for about 50% of the total industrial heat production. In practical applications, due to the lack of effective recycling methods, most of the low-temperature waste heat is directly discharged into the environment, which not only wastes a lot of energy, but also constitutes serious thermal pollution to the surrounding environment. Organic matter Rankine cycle low-temperature waste heat power generation technology is an effective low-temperature waste heat recovery and utilization method. It uses low-boiling point organic working fluid as an energy carrier to convert low-grade heat energy into electrical energy. When the temperature of the heat source is lower than 270°C, the organic Rankine cycle has a wide selection of working fluids, strong pertinence, and relatively simple equipment requirements. Compared with the conventional water vapor Rankine cycle, it has a higher energy utilization rate.

Ejector refrigeration technology was widely favored in the 1930s, but with the emergence of vapor compression refrigeration technology, the dominant position of ejector refrigeration technology was gradually replaced. In recent years, the ejector refrigeration system has become a research hotspot in the field of refrigeration technology due to its advantages of simple equipment, convenient maintenance, environmental protection and reliability, applicable to solar energy, geothermal energy, and low-temperature waste heat recovery. The distributed energy supply system refers to an energy supply system that is located near the user, has a small output, and is based on the principle of energy cascade utilization. Compared with traditional large-scale energy supply methods, distributed energy supply systems are highly efficient and environmentally friendly, and have flexible and diverse forms. In addition to power supply, they generally also have the function of cooling and heating. The distributed energy supply system of power-cooling cogeneration that has appeared in recent years is one of them.

After searching the prior art documents, Feng Xu et al published an article titled "a kind of power generation and refrigeration cycle" on the 25th volume 233-246 pages of "Energy" magazine in 2000, (Xu, F., Goswami, D.Y., and Bhagwat, S.S., 2000, "A Combined Power/Cooling Cycle," Energy, 25, pp.233-246.) This system combines organic Rankine cycle power generation technology with absorption refrigeration technology, and chooses binary solution as Working fluid, convert low-grade heat energy into electric energy and output cooling capacity at the same time, and propose a new scheme for recycling low-grade heat energy. However, there are certain deficiencies in this technology: first, in the refrigeration process, the working fluid does not undergo a phase change, and refrigeration is mainly achieved by the change of sensible heat of the working fluid, so the cooling capacity is limited to a certain extent; The carrier makes the system equipment structure and operation more complicated.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention proposes an integral injection type low-temperature waste heat power generation refrigeration device. The invention organically combines the organic Rankine cycle power generation system with the jet refrigeration cycle through a moderate boiling point, environmentally friendly and safe working medium, and simultaneously meets the needs of users for power and cooling capacity, and not only effectively improves the efficiency of the low-temperature waste heat recovery device. The overall energy utilization rate is high, and the whole process is simple and easy, clean and environmentally friendly, safe and reliable.

The present invention is realized through the following technical solutions, and the present invention includes: a working medium pump, a waste heat exchanger, a turbo generator, an ejector, a condenser, a liquid storage tank, a three-way valve, a throttle valve, and an evaporator. The outlet of the working fluid pump is connected to the working fluid inlet of the waste heat exchanger, the working fluid outlet of the waste heat exchanger is connected to the working fluid inlet of the turbogenerator, the working fluid outlet of the turbogenerator is connected to the working fluid inlet of the injector, and the working fluid of the injector The outlet is connected to the working medium inlet of the condenser, the working medium outlet of the condenser is connected to the working medium inlet of the liquid storage tank, the working medium outlet of the liquid storage tank is connected to the working medium inlet of the three-way valve, and one working medium outlet of the three-way valve is connected to the working medium pump The inlet is connected, another working medium outlet of the three-way valve is connected with the throttle valve working medium inlet, the throttle valve working medium outlet is connected with the evaporator working medium inlet, and the evaporator working medium outlet is connected with the injector injection fluid inlet.

During the working process of the device, the liquid saturated low-boiling point organic working medium is increased in pressure through the working medium pump, and is heated to a superheated state by using low-temperature waste heat in the waste heat recovery heat exchanger. The high-temperature and high-pressure gas then drives the turbine to rotate, and drives the generator set to output electric power. The working fluid gas discharged from the outlet of the turbine flows into the ejector as a relatively high-pressure working fluid, and injects the low-temperature and low-pressure gas at the outlet side of the evaporator into the ejector. The two are mixed and diffused in the ejector, and enter condensation. device. In the condenser, the organic working substance changes from gaseous state to liquid state under the cooling of groundwater, lake water, river water or sea water. The liquid working medium enters the liquid storage tank, and the working medium outlet of the liquid storage tank is connected with a three-way valve. A part of the liquid working medium enters the working medium pump through an outlet of the three-way valve, and is pressurized in the working medium pump to return to the waste heat recovery exchange. In the heater, the power generation cycle is completed, and another part of the liquid working medium enters the throttle valve through the other outlet of the three-way valve, where the temperature and pressure drop in the throttle valve, and then returns to the evaporator to complete the refrigeration cycle. During the entire cycle, low-grade heat energy is continuously recycled, and at the same time, the system continuously outputs electric energy and cooling capacity to users, thereby realizing the use of low-temperature waste heat for power generation and refrigeration.

According to the characteristics of the working fluid in the ideal adiabatic expansion process, the working fluid can be divided into two types: dry and wet. The saturated wet working fluid enters the two-phase region during the expansion process of the turbine, which has a great negative impact on the service life of the turbine blades. The saturated dry working fluid is easy to remain in the superheated area during the turbine expansion process. Therefore, in order to prevent the working medium from entering the two-phase region during the expansion process, the present invention selects safe and environment-friendly dry working medium. Such as: R245fa, R600, R600a, R141b, R123, R142b, etc.

The present invention organically combines the organic Rankine cycle with the jet refrigeration cycle by selecting a dry working medium with moderate working temperature and pressure, which is environmentally friendly and safe, and uses solar energy, geothermal energy, biomass energy, or various low-temperature waste heat as the system heat source. Use groundwater, river water, lake water, or seawater at a temperature of about 20°C as the cooling water for the system. While using the Rankine cycle of organic matter to generate electricity, the low-temperature and low-pressure working fluid entering the evaporator absorbs heat from the outside, changes from liquid to gaseous, and uses the latent heat of gasification of the working fluid to achieve refrigeration. The invention has the characteristics of high efficiency, environmental protection, simple components, and strong operability. Through the reasonable design of the turbine and ejector, it not only meets the requirements of the organic Rankine cycle and the ejector refrigeration cycle on the physical parameters of the working medium, but also simultaneously It solves the user's requirements for electric energy and cooling capacity, and conforms to the principle of energy cascade utilization, thus greatly improving the comprehensive utilization rate of energy.

Description of drawings

Fig. 1 is a structural representation of the present invention

Detailed ways

The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings: this embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following the described embodiment.

As shown in Figure 1, this embodiment includes: a working medium pump 1, a waste heat exchanger 2, a turbo generator 3, an ejector 4, a condenser 5, a liquid storage tank 6, a three-way valve 7, and a throttle valve 8 , Evaporator 9. Working medium pump 1 outlet is connected to waste heat exchanger 2 working medium inlet, waste heat heat exchanger 2 working medium outlet is connected to turbine generator 3 working medium inlet, turbo generator 3 working medium outlet is connected to ejector 4 working fluid inlet The working medium outlet of the injector 4 is connected with the working medium inlet of the condenser 5, the working medium outlet of the condenser 5 is connected with the working medium inlet of the liquid storage tank 6, and the working medium outlet of the liquid storage tank 6 is connected with the working medium inlet of the three-way valve 7, A working medium outlet of the three-way valve 7 is connected to the working medium pump 1 inlet, another working medium outlet of the three-way valve 7 is connected to the working medium inlet of the throttle valve 8, and the working medium outlet of the throttle valve 8 is connected to the working medium of the evaporator 9 The inlet is connected, and the working medium outlet of the evaporator 9 is connected with the injection fluid inlet of the injector 4 .

In this embodiment, the working fluid of the integrated injection type low-temperature waste heat power generation and refrigeration device is R245fa.

According to the requirements of the integrated injection type low-temperature waste heat power generation and refrigeration device, the following example assumes that the waste heat temperature is 150°C, the evaporation pressure of the waste heat exchanger is 1.26MPa, the turbine expansion ratio is 2.5, the turbine outlet pressure is 0.5MPa, and the condensation temperature of the condenser is 30°C. The pressure is 0.18MPa, the evaporator evaporation temperature is 8°C, the evaporator evaporation pressure is 0.076MPa, the ambient temperature is 25°C, and the cooling water temperature is 20°C.

1. The saturated liquid organic working medium R245fa at about 30°C is raised to 1.26MPa by the working medium pump 1 and sent to the waste heat exchanger 2 for heating.

2. The liquid working medium R245fa is heated to about 105°C by the low-temperature waste heat of about 150°C in the waste heat exchanger 2, the superheat degree is 5°C, and the pressure is 1.26MPa.

3. The gas working medium from the waste heat exchanger 2 enters the turbine generator 3 to drive the turbine generator 3 to rotate to do work and output electricity. After the working fluid expands through the turbine generator 3, the pressure drops to about 0.5MPa. According to the physical properties of R245fa, the working fluid expanded through the turbine generator 3 is still a superheated gas.

4. The R245fa superheated steam discharged from the turbine generator 3 enters the injector 4 as the working fluid, and injects the R245fa steam at the outlet side of the evaporator 9 into the injector 4, and the working fluid and the injected fluid are mixed in the injector mixing chamber Mix in the middle, and then restore the pressure to 0.18MPa through the diffuser, and the temperature is about 60°C.

5. The R245fa working gas flowing out of the injector 4 enters the condenser 5, and is cooled to a saturated liquid by groundwater, lake water or seawater at about 20°C, with a condensation pressure of about 0.18MPa and a temperature of about 30°C.

6. The condensate coming out of the condenser 5 enters the liquid storage tank 6, and the liquid storage tank 6 is connected with the three-way valve 7.

7. Part of the condensate enters the working medium pump 1 through a working medium outlet of the three-way valve 7, pressurizes in the working medium pump 1 and returns to the waste heat recovery heat exchanger 2 to complete the power generation cycle, and the other part of the condensate passes through the three-way valve 7. The other working medium outlet of the through valve 7 enters the throttling valve 8 to throttle and reduce pressure, the pressure drops to about 0.076MPa, and the temperature drops to about 8°C.

8. The R245fa liquid flowing out from the throttle valve 8 enters the evaporator 9 for evaporation, and at the same time provides cold water to the outside, the evaporation pressure is about 0.076MPa, and the evaporation temperature is about 8°C.

9. The R245fa steam flowing out of the evaporator 9 enters the ejector 4 as the injection fluid, thereby completing the entire cycle process and realizing the output of the system's electrical energy and cooling capacity.

Under the conditions of 85% turbine efficiency, 80% heat exchanger efficiency, and 80% pump efficiency, assuming that the system recovers 240KJ of heat from a low-temperature heat source at 150°C, the integrated jet-type low-temperature waste heat power generation and refrigeration device can provide users with Electricity 15KJ, cooling capacity 32KJ.

Claims (2)

1. An integral injection type low-temperature waste heat power generation refrigeration device, including: working fluid pump, waste heat heat exchanger, turbine generator, ejector, condenser, liquid storage tank, three-way valve, throttle valve, evaporator , which is characterized in that the outlet of the working fluid pump is connected with the inlet of the waste heat exchanger, the outlet of the waste heat exchanger is connected with the inlet of the turbogenerator, and the outlet of the turbogenerator is connected with the inlet of the working fluid of the injector. , the working fluid outlet of the injector is connected with the working medium inlet of the condenser, the working medium outlet of the condenser is connected with the working medium inlet of the liquid storage tank, the working medium outlet of the liquid storage tank is connected with the working medium inlet of the three-way valve, and one working medium of the three-way valve The outlet is connected to the inlet of the working medium pump, the other working medium outlet of the three-way valve is connected to the working medium inlet of the throttle valve, the working medium outlet of the throttle valve is connected to the working medium inlet of the evaporator, and the working medium outlet of the evaporator is connected to the injection ejector The fluid inlet is connected. 2. The integrated injection type low-temperature waste heat power generation and refrigeration device according to claim 1, characterized in that the working medium is selected as a dry working medium, which is one of R245fa, R600, R600a, R141b, R123, and R142b.