CN111057523B

CN111057523B - Medium-high temperature heat pump mixed working medium

Info

Publication number: CN111057523B
Application number: CN201911113182.2A
Authority: CN
Inventors: 王斌辉; 周黎旸; 宓宏; 李行行; 童灿辉; 王双双; 王金明
Original assignee: Zhejiang Juhua Research Institute Of New Materials Co ltd
Current assignee: Zhejiang Juhua Research Institute Of New Materials Co ltd
Priority date: 2019-11-14
Filing date: 2019-11-14
Publication date: 2021-03-16
Anticipated expiration: 2039-11-14
Also published as: CN111057523A

Abstract

The invention discloses a mixed working medium of a medium-high temperature pump, which consists of 1,1,1, 2-tetrafluoroethane and 1,1,1,3, 3-pentafluoropropane. The production method comprises the following steps: 1,1,1, 2-tetrafluoroethane (HFC-134a) and 1,1,1,3, 3-pentafluoropropane (HFC-245fa) were mixed in a liquid phase by means of a micromixer. The mixed working medium produced by the method is environment-friendly, good in thermal performance and long in service life, and the method is high in mixing efficiency and long in service life of a production device.

Description

Medium-high temperature heat pump mixed working medium

Technical Field

The invention belongs to the field of refrigeration, and particularly relates to a medium-high temperature heat pump mixed working medium.

Background

The heat pump is a device which can obtain low-level heat energy from air, water or soil in the nature and provide high-level heat energy which can be used by people through electric energy acting. In recent years, heat pump technology has been rapidly developed in the world, and japan, europe, and the like have been developed areas of heat pump technology. The heat pump market in China is in the starting stage, but along with increasingly prominent problems of air quality (such as haze), environmental protection and the like, the heat pump market is rapidly developed. The medium-high temperature heat pump is mainly applied to rapid dehydration of vegetables and fumigation of tobacco; compared with the traditional coal burning or boiler heating, the high-temperature heat pump is safe, environment-friendly and automatic. In order to meet the industrial requirements, the heat pump technology is developed towards medium-high temperature (the condensation temperature is 70-100 ℃) heat pumps, and high temperature (the condensation temperature is higher than 100 ℃). One of the key problems restricting the technical development of medium-high temperature heat pumps is lack of proper circulating working media.

The working fluid of the heat pump used in the past is CFC-11, CFC-114 and the like. However, since CFC-11 and CFC-114 both belong to CFC materials, the ozone depletion potential ODP is 1.0 and 0.85 respectively, the substances have serious destructive effect on the atmospheric ozone layer, the greenhouse effect influence is also great, the greenhouse effect potential GWP is 4600 and 9800 respectively, developed countries are forbidden in 1996, and developing countries are forbidden in 2010.

At present, most working media used by a heat pump are 1,1,1, 2-tetrafluoroethane (HFC-134a), but the working media cannot provide high outlet water temperature. The HFC-134a unit used for the water chilling unit of the air-conditioning heat pump generally provides hot water at 60-65 ℃, and if the hot water is higher, the condensation pressure is too high, the circulation performance is deteriorated, and the configuration of equipment, a system and a pipeline of the heat pump unit is seriously influenced. Therefore, a refrigeration working medium with a relatively high normal boiling point, namely a so-called medium-high temperature working medium, is required to be adopted to ensure a proper heat supply effect and also give consideration to an air conditioning effect.

CN200510115770.1 provides a mixed working medium with zero ozone destruction potential suitable for a compression heat pump, and relates to a mixed working medium used by a medium-high temperature heat pump unit. The working medium contains three substances of 1,1,1, 2-tetrafluoroethane, 1,1,1,2, 3,3, 3-heptafluoropropane and 1,1,1,3, 3-pentafluoropropane; or butane can be added into the three components to form a quaternary mixed working medium. The preparation method comprises mixing the above components in liquid phase according to their corresponding ratio. The heat pump unit can be directly used in an HFC-134a heat pump unit, and the compressor and main components in the system do not need to be changed; the heat pump unit using the mixed working medium can provide medium-high temperature heat of about 80 ℃. However, the GWP value of the 1,1,1,2, 3,3, 3-heptafluoropropane introduced by the patent is higher, so that the overall GWP is higher, and the method is not beneficial to environmental protection.

CN200910263143.0 relates to a high temperature heat pump mixed working medium. The first scheme comprises the following components in percentage by mass: HCFC-124 (monochloro-1, 2, 2, 2-tetrafluoroethane) accounts for 50-90%, HCFC-142b (monochloro-1, 1-difluoroethane) accounts for 10-50%. The high-temperature heat pump mixed working medium is environment-friendly, has excellent thermal performance and can meet the use requirement of a medium-high temperature heat pump system with the condensation temperature of 70-105 ℃. The components used in this patent all have ODP values, HCFC-124 (monochloro-1, 2, 2, 2-tetrafluoroethane) is 0.026, HCFC-142b (monochloro-1, 1-difluoroethane is 0.043, and are not environmentally friendly.

CN03149761.6 relates to a quaternary medium-high temperature refrigeration working medium suitable for a normal temperature water source heat pump, and relates to a refrigerant capable of providing medium-high temperature hot water at about 70 ℃. The refrigerant contains 10-90% of 1,1,1, 2-tetrafluoroethane (HFC-134a), 6-85% of 1-chloro-1, 2, 2, 2-tetrafluoroethane (HCFC-124), 1-5% of isobutane (HC-600a) and 3-30% of 1, 1-difluoroethane (HFC-152 a). Except that the normal temperature water source of about 30 ℃ can be directly utilized, the heat pump system can also be directly used in an HFC-134a heat pump unit, and the compressor and main components in the system do not need to be changed. Hot water with the temperature of about 70 ℃ is provided for users in winter, and the air-conditioning requirements of the users are met in summer. The patent contains 1-chloro-1, 2, 2, 2-tetrafluoroethane (HCFC-124), the ODP value is not zero and is 0.026, and the patent is not environment-friendly.

CN03149762.4 provides a binary medium-high temperature refrigeration working medium suitable for a normal temperature water source heat pump, and relates to a refrigerant capable of providing medium-high temperature hot water. The refrigerant contains two components of 1,1,1, 2-tetrafluoroethane (HFC-134a) and 1-chloro-1, 2, 2, 2-tetrafluoroethane (HCFC-124). The invention completely meets the requirement of environmental protection, is non-toxic and non-flammable, has better thermal performance and thermal parameters, can directly utilize a normal temperature water source (about 30 ℃), can also be directly used in an HFC-134a heat pump unit, and has no need of changing a compressor and main components in the system. Hot water with the temperature of about 70 ℃ is provided for users in winter, and the air-conditioning requirements of the users are met in summer. The patent contains 1-chloro-1, 2, 2, 2-tetrafluoroethane (HCFC-124), the ODP value is not zero, and the patent is not environment-friendly.

CN1233779 discloses a group of high-temperature heat pump mixed working medium, which is a binary and ternary mixture composed of six substances of HCFC-123, HCFC-124, HFC-134a, HCFC-142b, HFC-152a and HFC-245fa according to different mass proportions. The components are physically mixed at normal temperature according to the specified proportion, and the refrigerant is suitable for being used as the refrigerant of a high-temperature heat pump system with the condensation temperature of 100-160 ℃. The patent claims are not directed to binary systems. Meanwhile, substances except HFC-134a and HFC-245fa contain ODP values, so that the method is not environment-friendly. In addition, the average evaporation temperature mentioned in the list is 70 ℃ which means that the temperature requirement on the waste heat source is higher, while the waste heat source adopted in the patent is more extensive at 35 ℃ and adopts environment-friendly and easily available refrigerant.

As the novel compound refrigerant, no novel HFO series is added, the refrigerant is a commonly used and easily available refrigerant, and the influence of potential decomposed TFA (trifluoroacetic acid) on environmental acidification is avoided. Moreover, the compounded refrigerant can complete the working condition of HFC-134a, has more efficient heating effect and lower pressure and exhaust temperature, ensures that the system runs more stably and has longer service life, and is compatible with a heat pump unit developed based on HFC-134a and POE lubricating oil.

Meanwhile, the existing preparation method of the compound mixing of the refrigerant utilizes the mechanical stirring and disturbance action to mix the refrigerant, or adds the surfactant to form microemulsion, so that the microemulsion is difficult to be uniformly distributed in a compound system, even if the additive is added, external stirring or circulation is continuously applied to promote the compound mixing, and the existence and continuity of the external force greatly influence the compound mixing degree.

Disclosure of Invention

The invention aims to provide a method for producing medium-high temperature mixed working medium suitable for a normal temperature heat pump unit, the mixed working medium produced by the method is environment-friendly, good in thermal performance and long in service life, and the method is high in mixing efficiency and long in service life of a production device.

In order to solve the technical problems, the invention adopts the following technical scheme:

the medium-high temperature heat pump mixed working medium is characterized in that: is composed of 1,1,1, 2-tetrafluoroethane and 1,1,1,3, 3-pentafluoropropane.

Preferably, the mass percentage content of the 1,1,1, 2-tetrafluoroethane and the 1,1,1,3, 3-pentafluoropropane is 10-80%: 20 to 90 percent.

The production method of the medium-high temperature heat pump mixed working medium is characterized by comprising the following steps: 1,1,1, 2-tetrafluoroethane (HFC-134a) and 1,1,1,3, 3-pentafluoropropane (HFC-245fa) were mixed in a liquid phase by means of a micromixer.

Preferably, the mass percentage content of the 1,1,1, 2-tetrafluoroethane and the 1,1,1,3, 3-pentafluoropropane is 1,1,1, 2-tetrafluoroethane: 1,1,1,3, 3-pentafluoropropane 10-80%: 20 to 90 percent.

Preferably, the micromixer is a T-type or Y-type polypropylene micromixer.

Preferably, the channel equivalent diameter of the micromixer is 10 to 200 μm.

Preferably, the micromixer is radiation modified.

Preferably, the step of modifying by irradiation is:

(1) immersing the micro mixer into the immersion liquid, and fishing out after immersing for 1-5 h;

(2) placing the micro mixer for 10-24h at normal temperature;

(3) sending the micro mixer into an electron irradiation to carry out cross-linking treatment;

(4) and filtering and drying the micro mixer, and blowing the micro mixer by using high-pressure nitrogen to obtain the irradiation modified micro mixer.

Preferably, the mass ratio of the micromixer to the immersion liquid in the step (1) is 1: 10-30.

Preferably, the preparation method of the impregnation liquid comprises the following steps: 0.05-0.2 part of triallyl (phenyl) silane, 0.2-5 parts of vinyl difluoro-borane, 100 parts of dimethyl silicone oil and 500 parts of dimethyl silicone oil are mixed for 1-5 hours at 50-70 ℃ to obtain the impregnation liquid.

Preferably, the parameters of the electron irradiation crosslinking treatment are as follows: the electron beam current is 12-16mA, and the accelerator energy is 0.5-0.9 McV.

Due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. environmental performance: the ODP value of the mixed working medium is 0, and the GWP value is lower than HFC-134 a. The GWP of HFC-134a is 1300, the GWP of HFC-245fa is 858(IPCC 5 th edition), and the ratio of 80% HFC-134a to 20% HFC-245fa at the most boundary is calculated, so that the GWP of the compounded high-temperature heat pump working medium is 1211, which is reduced by about 7%, and the GWP of the implementation comparative example is 1123, which is reduced by about 15%. The invention completely meets the requirements of protecting the ozone layer, reducing the emission of greenhouse gases and meeting the requirements of environmental protection.

2. Thermal parameters are as follows: under the same working condition, the evaporation pressure and the condensation pressure of the mixed working medium are both lower than HFC-134a, which shows that the mixed working medium can be directly filled in the original HFC-134a system without changing other parts, and can provide higher outlet water temperature (above 80 ℃).

3. Performance parameters: the pressure of the mixed working medium is far lower than that of HFC-134a by nearly 0.7MPa and reaches nearly 30 percent, which means that the system is very stable and the service life is longer.

4. The mixed working medium is polymerized with the irradiation grafted fluorine-containing silicon on the surface of the inner wall of the micro mixer pipeline to form a polymer, which is beneficial to improving the compatibility of the surface of the micro mixer pipeline with 1,1,1, 2-tetrafluoroethane (HFC-134a) and 1,1,1,3, 3-pentafluoropropane (HFC-245fa), and the problem that the mixing efficiency is influenced due to large resistance caused by the occurrence of micro bubbles due to insufficient contact is avoided. Meanwhile, the polymer forms a protective film on the inner wall of the pipeline of the micro mixer, so that the mixed working medium is prevented from directly contacting with the pipeline of the micro mixer, and the swelling resistance of the pipeline material of the micro mixer to 1,1,1, 2-tetrafluoroethane (HFC-134a) and 1,1,1,3, 3-pentafluoropropane (HFC-245fa) is improved.

Drawings

The invention is further illustrated below with reference to the accompanying drawings.

FIG. 1 is a pressure vs. temperature comparison of the working mixture of example 2 with a blank of comparative example 1 using only HFC-134 a.

FIG. 2 is a comparison chart of vapor phase specific enthalpy values of a blank using HFC-134a as the working fluid mixture of example 2.

Wherein, 1-HFC-134 a; 2-mixed working medium liquid phase of embodiment 2; 3-example 2 mixed working substance gas phase.

Detailed Description

The detection method of the high-temperature heat pump mixed working medium in the embodiment is as follows:

the experimental method comprises the following steps: the testing machine set is a medium-sized screw machine set, the evaporation section and the condensation section are both in a water cooling mode, the model of a compressor is Han's clock RC2-550B-ZP, the power system is 380V/50Hz, the rated power is 264.3kw, and 650 kg of refrigerant is filled. The refrigerant ratio is quantified according to a GC gas chromatography method, and after full circulation, the filling test of a test unit is carried out after ton bottle packaging. The test conditions are that the evaporation temperature is 30 ℃, the condensation temperature is 85 ℃, the superheat degree is 8 ℃, the supercooling temperature is 4 ℃, and the effluent is about 80 ℃.

Example 1:

0.08 part by weight of triallyl (phenyl) silane, 0.6 part by weight of vinyl difluoro-borane, 220 parts by weight of simethicone, were mixed at 55 ℃ for 3 hours to obtain a dipping solution.

Immersing a T-shaped polypropylene micro mixer into the dipping solution, wherein the weight ratio of the T-shaped polypropylene micro mixer to the dipping solution is 1: and 18, soaking for 2 hours, taking out, standing at room temperature for 19 hours, then carrying out electron irradiation crosslinking treatment, wherein the electron beam current is 15mA, the accelerator energy is 0.7McV, filtering, drying, and purging with high-pressure nitrogen to obtain the irradiation modified micro mixer. The channel equivalent diameter of the radiation-modified micromixer was 50 μm.

1,1,1, 2-tetrafluoroethane 10%

90 percent of 1,1,1,3, 3-pentafluoropropane

The components flow through a micro mixer for irradiation modification in a liquid phase state according to corresponding proportions, and physical mixing is carried out, so that the medium-high temperature mixed working medium suitable for the normal-temperature heat pump unit can be obtained.

Example 2

0.05 part by weight of triallyl (phenyl) silane, 0.2 part by weight of vinyl difluoro-borane, 100 parts by weight of simethicone, were mixed at 50 ℃ for 3 hours to obtain a dipping solution.

Immersing a Y-shaped polypropylene micro mixer into the dipping solution, wherein the weight ratio of the Y-shaped polypropylene micro mixer to the dipping solution is 1:10, soaking for 1h, taking out, standing at room temperature for 10h, then sending into an electron irradiation crosslinking treatment with an electron beam current of 12mA and an accelerator energy of 0.5McV, filtering, drying, and purging with high-pressure nitrogen to obtain the irradiation modified micro-mixer. The channel equivalent diameter of the radiation-modified micromixer was 10 μm.

60 percent of 1,1,1, 2-tetrafluoroethane

40 percent of 1,1,1,3, 3-pentafluoropropane

Example 3

0.2 part by weight of triallyl (phenyl) silane, 5 parts by weight of vinyl difluoro-borane, 500 parts by weight of simethicone, were mixed for 5 hours at 70 ℃ to obtain a dipping solution.

Immersing a T-shaped polypropylene micro mixer into the dipping solution, wherein the weight ratio of the T-shaped polypropylene micro mixer to the dipping solution is 1: 30, soaking for 5 hours, taking out, standing at room temperature for 24 hours, then sending into electron irradiation for crosslinking treatment, wherein the electron beam current is 16mA, the accelerator energy is 0.9McV, and then filtering, drying and purging with high-pressure nitrogen to obtain the irradiation modified micro mixer. The channel equivalent diameter of the radiation-modified micromixer was 200. mu.m.

80 percent of 1,1,1, 2-tetrafluoroethane

20 percent of 1,1,1,3, 3-pentafluoropropane

Example 4

0.05 part by weight of triallyl (phenyl) silane, 0.2 part by weight of vinyl difluoro-borane, 500 parts by weight of simethicone, were mixed at 70 ℃ for 5 hours to obtain a dipping solution.

Immersing a T-shaped polypropylene micro mixer into the dipping solution, wherein the weight ratio of the T-shaped polypropylene micro mixer to the dipping solution is 1: 30, soaking for 1h, taking out, standing at room temperature for 10h, then sending into an electron irradiation crosslinking treatment with an electron beam current of 16mA and accelerator energy of 0.5McV, filtering, drying, and purging with high-pressure nitrogen to obtain the irradiation modified micro-mixer. The channel equivalent diameter of the radiation-modified micromixer was 200. mu.m.

50 percent of 1,1,1, 2-tetrafluoroethane

50 percent of 1,1,1,3, 3-pentafluoropropane

Example 5

0.05 part by weight of triallyl (phenyl) silane, 5 parts by weight of vinyl difluoro-borane, 100 parts by weight of simethicone, were mixed at 70 ℃ for 1 hour to obtain a dipping solution.

Immersing a Y-shaped polypropylene micro mixer into the dipping solution, wherein the weight ratio of the Y-shaped polypropylene micro mixer to the dipping solution is 1:10, soaking for 1h, taking out, standing at room temperature for 24h, then sending into an electron irradiation crosslinking treatment with an electron beam current of 16mA and an accelerator energy of 0.5McV, filtering, drying, and purging with high-pressure nitrogen to obtain the irradiation modified micro mixer. The channel equivalent diameter of the radiation-modified micromixer was 200. mu.m.

60 percent of 1,1,1, 2-tetrafluoroethane

40 percent of 1,1,1,3, 3-pentafluoropropane

Example 6

A mixed working medium is prepared according to the embodiment 2, and the embodiment 2 is additionally tested according to the following working conditions, wherein the test working conditions comprise that the evaporation temperature is 30 ℃, the condensation temperature is 75 ℃, the superheat degree is 8 ℃, the supercooling temperature is 4 ℃, and the effluent is about 70 ℃.

Comparative example 1

650 kg of 1,1,1, 2-tetrafluoroethane (HFC-134a) was selected, charged into a ton bottle, and then pumped to a specified amount and stopped. Since HFC-134a alone can not produce water at 80 ℃, only 70 ℃ can be used as a control. The test conditions are that the evaporation temperature is 30 ℃, the condensation temperature is 75 ℃, the superheat degree is 8 ℃, the supercooling temperature is 4 ℃, and the effluent is about 70 ℃.

Comparative example 2

According to the component proportion of the embodiment 4:

50 percent of 1,1,1, 2-tetrafluoroethane

50 percent of 1,1,1,3, 3-pentafluoropropane

The components flow through a micro mixer which is not modified by irradiation in a liquid phase state according to the corresponding proportion, and the medium-high temperature mixed working medium which is suitable for the normal temperature heat pump unit can be obtained by physical mixing.

The thermal performance environment properties of examples 1-6 and comparative example 1 are shown in table 1.

Table 1: thermal performance environmental Properties

As can be seen from Table 1, the mixed working medium prepared by the invention is environment-friendly, because the GWP of HFC-245fa is 858, which is lower than that of HFC-134a, so that the GWP value of the mixed working medium is lower than that of pure HFC-134a, and the mixed working medium does not contain ODP value and is more environment-friendly. From the examples 1-6, it can be seen that the exhaust pressure of the composite working medium is low under the condition of high-temperature water outlet, the system is friendly, and COP (coefficient of performance) is good_hIs high. Comparative example 4 and comparative example 1 COP of composite working fluids_hCOP than HFC-134a_hThe height is about 5 percent. Therefore, the composite working medium prepared by the method of the invention has the advantages of energy conservation and emission reduction, and can realize higher-temperature air outlet or water outlet which cannot be realized by HFC-134 a.

Comparing example 4 with comparative example 2, COP in example 4_hThe value is higher than the COP in comparative example 2_hThe lower values, and the lower discharge pressures, illustrate that the irradiation modified micromixer of example 4 is better able to thoroughly mix HFC-134a and HFC-245fa than the non-irradiation modified micromixer of comparative example 2.

The physical properties of examples 1-5 and comparative example 1 were further analyzed, and the critical temperature and critical pressure are shown in Table 2.

Table 2: critical temperature and critical pressure comparison of examples 1-5 with comparative example 1

	Critical temperature (. degree.C.)	Critical pressure (MPa)
			Example 1	148.4	3.84
Example 2	120.1	4.16
			Example 3	110	4.12
Example 4	125.5	4.16
			Example 5	136.9	4.08
Comparative example 1	101.1	4.06

As can be seen from Table 2, the critical temperatures of the mixed working fluids with different proportions are different, which also means that different formulations can give different outlet water temperatures. The higher the critical temperature is, the higher the outlet water temperature is, and the corresponding proportion is selected according to the working condition.

The thermal performance environment properties of example 6 and comparative example 1 were tested and the results are shown in fig. 1 and 2.

As can be seen from fig. 1, the pressure of the mixed working fluid is much lower than HFC-134a, which means that the system will be stable and have a longer working life.

As can be seen from fig. 2, the vapor phase enthalpy of the mixed working medium is almost the same, but HFC-134a is greatly attenuated when reaching high temperature, but the mixed working medium is not, which indicates that the mixed working medium has great superiority in high temperature water outlet or air outlet.

The above is only a specific embodiment of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions or modifications made on the basis of the present invention to solve the same technical problems and achieve the same technical effects are all covered in the protection scope of the present invention.

Claims

1. The production method of the medium-high temperature heat pump mixed working medium is characterized by comprising the following steps: mixing 1,1,1, 2-tetrafluoroethane and 1,1,1,3, 3-pentafluoropropane in a liquid phase state through a micromixer, wherein the micromixer is modified by irradiation, the micromixer is a T-type or Y-type polypropylene micromixer, and the irradiation modification comprises the following steps:

(1) mixing 0.05-0.2 part of triallyl (phenyl) silane, 0.2-5 parts of vinyl difluoro-borane, 100 parts of dimethyl silicone oil and 500 parts of dimethyl silicone oil at 50-70 ℃ for 1-5h to obtain a dipping solution;

(2) immersing the micro mixer into the immersion liquid, and fishing out after immersing for 1-5 h;

(3) placing the micro mixer for 10-24h at normal temperature;

(4) sending the micro mixer into an electron irradiation to carry out cross-linking treatment;

(5) and filtering and drying the micro mixer, and blowing the micro mixer by using high-pressure nitrogen to obtain the irradiation modified micro mixer.

2. The production method of the medium-high temperature heat pump mixed working medium according to claim 1, characterized in that: the mass percentage content of the 1,1,1, 2-tetrafluoroethane and the 1,1,1,3, 3-pentafluoropropane is 10-80%: 20 to 90 percent.

3. The production method of the medium-high temperature heat pump mixed working medium according to claim 1, characterized in that: the equivalent diameter of the channel of the micro mixer is 10-200 μm.

4. The production method of the medium-high temperature heat pump mixed working medium according to claim 1, characterized in that: the mass ratio of the micro mixer to the dipping solution in the step (2) is 1: 10-30.

5. The production method of the medium-high temperature heat pump mixed working medium according to claim 1, characterized in that: the parameters of the electron irradiation crosslinking treatment are as follows: the electron beam current is 12-16mA, and the accelerator energy is 0.5-0.9 McV.