Absorption refrigerant pair driven by low-temperature heat source
By using a eutectic solvent system composed of alcohols and zwitterionic compounds, the problem of low absorption refrigeration efficiency under low-temperature heat sources is solved, achieving high-efficiency absorption performance and equipment-friendly low-temperature refrigeration effect, which is suitable for low-temperature industrial waste heat utilization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
- Filing Date
- 2023-06-14
- Publication Date
- 2026-07-21
AI Technical Summary
Existing absorption refrigeration systems are inefficient at heat source temperatures below 90°C, have insufficient absorption capacity of the absorbent, are prone to crystallization and are expensive, and are difficult to effectively utilize low-temperature industrial waste heat.
Alcohols are used as refrigerants and zwitterionic compounds as absorbents to form a eutectic solvent system. By combining specific ratios and stirring methods, a low-temperature heat source-driven absorption refrigerant pair is prepared. The low boiling point, volatility, low viscosity and low corrosiveness of the absorbent are utilized to solve the problems of absorbent separation and equipment corrosion.
It achieves high absorption performance at a heat source temperature of 65℃, the solution is not prone to crystallization, it is inexpensive, has low corrosiveness to equipment, is suitable for distributed miniaturized refrigeration equipment, and simplifies the preparation process.
Smart Images
Figure CN116790225B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of refrigeration technology, specifically a pair of absorption refrigerants driven by a low-temperature heat source. Background Technology
[0002] Absorption refrigeration driven heat sources can provide heat sources for low-grade industrial heat sources (industrial waste heat, residual heat) and renewable energy sources. They have the characteristics of extremely low power consumption and are a type of low-carbon / zero-carbon energy utilization technology that can be applied to large-scale industrial waste heat recovery and small-scale decentralized refrigeration.
[0003] Currently, commercially mature absorption refrigeration systems include water-lithium bromide and ammonia-water systems. However, their driving heat source temperatures typically need to be above 90°C, making it difficult to effectively utilize heat source energy below this temperature (such as lower-temperature industrial waste heat or solar-powered hot water). To date, the working fluid pair systems developed for lower heat source temperatures are classified by absorbent, including those using ionic liquids, eutectic solvents, organic solvents, and other solvents. The main drawbacks include:
[0004] 1) The absorption capacity of the absorbent is insufficient, and a compressor is often required to assist in absorption;
[0005] 2) If the absorbent viscosity is too high, crystallization problems are likely to occur;
[0006] 3) The working medium is expensive or difficult to synthesize.
[0007] Therefore, how to develop a new working fluid pair system to solve the above problems, and establish a new absorption refrigeration system based on this working fluid system to achieve effective recovery and utilization of heat source energy above 65°C, so as to reduce waste heat loss and achieve the goal of energy conservation and emission reduction, is a major problem that urgently needs to be solved. Summary of the Invention
[0008] The purpose of this invention is to address the problems existing in the prior art by providing a low-temperature heat source-driven absorption refrigerant pair. This low-temperature heat source-driven absorption refrigerant pair solves the problems of high driving heat source temperature and poor applicability of traditional refrigerant pairs, achieving a driving heat source temperature of around 65°C; it also solves the problems of absorbent volatility, high viscosity, and strong corrosiveness to equipment, and is environmentally friendly.
[0009] To achieve the above-mentioned objectives, the technical solution of this invention is as follows:
[0010] A low-temperature heat source-driven absorption refrigerant pair includes a refrigerant and an absorbent, wherein the refrigerant is an alcohol compound and the absorbent is a zwitterionic compound.
[0011] Furthermore, in the absorption refrigerant pair driven by the low-temperature heat source, the alcohol compound is selected from any one or a mixture of several of methanol, ethanol, ethylene glycol, glycerol, n-butanol or benzyl alcohol; more preferably, it is methanol.
[0012] In a preferred embodiment of this application, the zwitterionic compound is any one or a combination of several of the following: N,N,N-trimethylglycine, 3-sulfopropylhexadecyl dimethyl betaine, 3-sulfopropyldodecyl dimethyl betaine, 3-sulfopropyltetradecyl dimethyl betaine, 3-sulfopropyldecyl dimethyl betaine, 3-sulfopropyloctadecyl dimethyl betaine, 3-(decyldimethylammonium)propanesulfonate inner salt, and 3-(propyldimethylammonium)propanesulfonate inner salt.
[0013] Furthermore, in the aforementioned absorption refrigerant pair driven by a low-temperature heat source, the zwitterionic compound is a betaine compound, more preferably betaine (molecular formula C5H). 11 NO2).
[0014] In a preferred embodiment of this application, the mass ratio of the refrigerant to the absorbent is 1.97:1 to 3.95:1; specifically, it can be 1.97:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3.0:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1, 3.95:1, etc.
[0015] As a preferred embodiment of this application, the preparation method of the absorption refrigerant pair driven by the low temperature heat source includes the following steps: weighing the raw materials according to the proportion, then adding the absorbent to the refrigerant in a fume hood at room temperature, and making the absorbent fully mixed and dissolved under mechanical stirring, and sealing and storing after mixing.
[0016] As a preferred embodiment of this application, the mixing temperature during mechanical stirring is 25-30°C.
[0017] In a preferred embodiment of this application, the alcohol compound is a high-purity alcohol with a purity >99.9%; the zwitterionic compound absorbent has a purity >98%.
[0018] As a preferred embodiment of this application, the absorption refrigerant driven by the low-temperature heat source can achieve a maximum saturated vapor pressure of 965 mbar at 65°C.
[0019] The aforementioned main solution of the present invention and its various further alternative solutions can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed by the present invention; furthermore, the (non-conflicting alternatives) can also be freely combined with each other and with other alternatives. Those skilled in the art, after understanding the solution of the present invention, will realize that there are many combinations based on existing technology and common knowledge, all of which are technical solutions to be protected by the present invention, and will not be exhaustively listed here.
[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0021] (i) In the absorption refrigerant pair driven by the low temperature heat source in this application, alcohol compounds are selected as refrigerants. This is because they have the characteristics of low boiling point, easy volatility, large vaporization enthalpy, small specific heat capacity and low corrosivity in the working fluid pair, which can ensure that they can separate from the absorbent at a lower heat source temperature.
[0022] (ii) In the absorption refrigerant pair driven by the low temperature heat source in this application, zwitterionic compounds are selected as absorbents because they have low specific heat capacity, good thermal stability and chemical stability, strong ability to absorb refrigerant, low saturated vapor pressure and easy separation from refrigerant.
[0023] (iii) The refrigerant working fluid pair developed in this application is a eutectic solvent system. Strong hydrogen bonds are formed between the refrigerant and the absorbent, and the absorbent hardly volatilizes at the operating temperature, thus maintaining a low vapor pressure at low temperatures and having good absorption performance.
[0024] (iv) The novel absorption refrigerant pair of the present invention has low viscosity, is not prone to crystallization, and has a saturated solution viscosity at 25°C. 5 mPa·s. At a temperature of 30℃, the saturated vapor pressure can reach a minimum of 93 mbar, exhibiting good absorption performance and a low evaporation temperature at the evaporation pressure determined by the absorption pressure. At 65℃, the saturated vapor pressure can reach a maximum of 965 mbar, demonstrating relatively ideal generation performance.
[0025] (v) The refrigerant working fluid pair described in this invention is inexpensive and has very low corrosiveness to stainless steel, which is beneficial for equipment maintenance. Experiments have shown that after stainless steel is immersed in the above working fluid pair system for 2 months, its mass loss is <0.385‰.
[0026] (vi) The working fluid of the present invention is easy to prepare into a solution, does not require an additional separation process, and can realize a distributed miniaturized refrigeration device, which has advantages in portable applications. Attached Figure Description
[0027] Figure 1 Structural diagrams of four sulfonic acid betaines
[0028] Figure 2 Structural diagrams of four types of phosphate betaine Detailed Implementation
[0029] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.
[0030] It should be noted that, in order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.
[0031] Furthermore, it should be noted that, unless otherwise specified, the structures, connections, positions, power sources, etc. involved in this invention are all things that a person skilled in the art can know without creative effort based on the prior art.
[0032] The raw materials used in the following examples are all commercially available products.
[0033] Example 1:
[0034] This invention provides an absorption refrigerant pair for heat source temperatures of 65°C and above. The concentration of this pair is 2.5g of absorbent (betaine, molecular formula C5H) per 20ml of refrigerant (methanol). 11 NO2), then stir both in a container until completely dissolved to obtain the final product. The saturated vapor pressure was determined by observing the boiling phenomenon using a dynamic observation method. At 30℃, the saturated vapor pressure of the solution was 137 mbar; at 65℃, the saturated vapor pressure of the solution was 930 mbar.
[0035] Example 2:
[0036] This invention provides an absorption refrigerant pair for heat source temperatures of 65°C and above. The concentration of the working fluid pair is 3g of absorbent (betaine, molecular formula C5H) per 20ml of refrigerant (methanol). 11NO2), and both are stirred in a container until completely dissolved to obtain the final product. The saturated vapor pressure is determined by observing the boiling phenomenon using a dynamic observation method. At a temperature of 30°C, the saturated vapor pressure of the solution is 103 mbar; at a temperature of 65°C, the saturated vapor pressure of the solution is 924 mbar.
[0037] Example 3:
[0038] This invention provides an absorption refrigerant pair for heat source temperatures of 65°C and above. The concentration of the working fluid pair is 3.5g of absorbent (betaine, molecular formula C5H) per 20ml of refrigerant (methanol). 11 NO2), and both are stirred in a container until completely dissolved to obtain the final product. The saturated vapor pressure is determined by observing the boiling phenomenon using a dynamic observation method. At a temperature of 30°C, the saturated vapor pressure of the solution is 103 mbar; at a temperature of 65°C, the saturated vapor pressure of the solution is 911 mbar.
[0039] Example 4:
[0040] This invention provides an absorption refrigerant pair for heat source temperatures of 65°C and above. The concentration of the working fluid pair is 4g of absorbent (betaine, molecular formula C5H) per 20ml of refrigerant (methanol). 11 NO2), and both are stirred in a container until completely dissolved to obtain the final product. The saturated vapor pressure is determined by observing the boiling phenomenon using a dynamic observation method. At a temperature of 30°C, the saturated vapor pressure of the solution is 93 mbar; at a temperature of 65°C, the saturated vapor pressure of the solution is 902 bar.
[0041] The embodiments described above are merely preferred embodiments of this patent, but the scope of protection of this patent is not limited thereto. It should be noted that, for those skilled in the art, without departing from the principles of this patent, several improvements and modifications can be made based on the technical solution and patent concept of this patent, and these improvements and modifications should also be considered within the scope of protection of this patent.
Claims
1. A low-temperature heat source driven absorption refrigerant pair, comprising a refrigerant and an absorbent, characterized in that: The refrigerant is an alcohol compound; the absorbent is a zwitterionic compound; the alcohol compound is selected from any one of methanol, ethanol, ethylene glycol, glycerol, n-butanol, or benzyl alcohol; the zwitterionic compound is any one of N,N,N-trimethylglycine, 3-sulfopropylhexadecyl dimethyl betaine, 3-sulfopropyldodecyl dimethyl betaine, 3-sulfopropyltetradecyl dimethyl betaine, 3-sulfopropyldecyl dimethyl betaine, 3-sulfopropyloctadecyl dimethyl betaine, 3-(decyldimethylammonium)propanesulfonate inner salt, and 3-(propyldimethylammonium)propanesulfonate inner salt; the low temperature is a heat source temperature of 65°C or above; the mass ratio of refrigerant to absorbent is 1.97:1-3.95:
1.
2. The absorption refrigerant pair driven by a low-temperature heat source as described in claim 1, characterized in that: The zwitterionic compound is a betaine compound.
3. The absorption refrigerant pair driven by a low-temperature heat source as described in claim 1, characterized in that: The alcohol compound mentioned is methanol.
4. The method for preparing an absorption refrigerant pair driven by a low-temperature heat source as described in any one of claims 1-3, characterized in that... The process includes the following steps: weigh the raw materials according to the proportion, then add the absorbent to the refrigerant in a fume hood at room temperature, and use mechanical stirring to fully mix and dissolve the absorbent. After mixing, seal and store the mixture.
5. The method for preparing an absorption refrigerant pair driven by a low-temperature heat source as described in claim 4, characterized in that: The mixing temperature during mechanical stirring is 25-30℃.
6. The method for preparing an absorption refrigerant pair driven by a low-temperature heat source as described in claim 5, characterized in that: The alcohols are high-purity alcohols with a purity >99.9%; the zwitterionic compound absorbent has a purity >98%.
7. The absorption refrigerant pair driven by a low-temperature heat source obtained by the method described in claim 5 or 6, characterized in that: The absorption refrigerant driven by this low-temperature heat source can achieve a maximum saturated vapor pressure of 965 mbar at 65°C.