Method and system for processing liquid products with a combined heat pump coupled with a turbulent ball tower
Patent Information
- Application Number
- CN202510540183.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-27
- Publication Date
- 2026-11-03
AI Technical Summary
In the existing chemical, light industrial, and food industries, the traditional fossil fuel heating and circulating water cooling methods in the processing of liquid products result in high energy consumption and environmental pollution, making it difficult to achieve efficient heat energy recycling and improve solution processing efficiency.
The composite heat pump coupled turbulent sphere tower technology utilizes inert gas working fluid to achieve combined cooling/heating through direct contact heat and mass transfer in a semi-closed cycle. Combined with the efficient heat and mass transfer between the working fluid and the solution at the gas-liquid interface within the turbulent sphere tower, a semi-closed cycle system is constructed, simplifying equipment and improving efficiency.
It achieves low-energy combined cooling/heating, improves the processing efficiency of liquid products, reduces energy consumption and environmental pollution, and enhances economic and ecological benefits.
Smart Images
Figure CN123028409A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the processing of liquid products, including heating, cooling, evaporation and concentration, degassing and impurity removal, which are widely used in the chemical, light industry, and food industries. In particular, it relates to new technologies such as composite heat pumps that provide both heating and cooling, and green heat pump working fluids that directly contact the heat source / heat sink solution for heat and mass transfer, providing a new path for low-carbon transformation in these fields. Background Technology
[0002] In the chemical, light, and food industries, a large number of solution processing processes such as evaporation, concentration, and degassing are used. These processes generally rely on fossil fuels for heating and circulating water for cooling, forming the hot and cold ends. For example, a wet phosphoric acid evaporation and concentration unit with an annual output of 300,000 tons (P2O5) (Zhang Yigui et al. Multi-stage evaporation design of wet phosphoric acid concentration unit. Sulfur and phosphorus design and powder engineering, 2004, (2): 1~6) uses steam to heat a 28% (P2O5 mass concentration) crude phosphoric acid aqueous solution and concentrate it into an industrial-grade phosphoric acid product with a concentration of 50%. It inputs 480,000 tons of steam per year from the heating end and emits an equal amount of water vapor into the atmosphere through circulating water from the cooling end. This consumes more than 58,000 tons (standard coal) of fossil energy per year, all of which becomes environmental thermal pollution. This traditional processing mode does not conform to the development direction of a resource-saving and low-carbon society and urgently needs technological innovation and improvement. From a materials science perspective, this processing method only requires separating 471,400 tons of water from 1,071,400 tons of crude phosphoric acid solution with a concentration of 28% to obtain 600,000 tons of industrial-grade phosphoric acid product with a concentration of 50%. From a technological innovation perspective, the problem to be solved is to cleverly construct a process and method / system that uses energy in a cycle at both the hot and cold ends, namely, the method and system for processing liquid products using a composite heat pump coupled to a turbulent spherical tower as described in this invention. The processed liquid products include, but are not limited to, the above-mentioned solution evaporation and concentration. It can be applied to any situation involving simultaneous solution heating and cooling, such as the process in the food industry where large quantities of liquid products (including fresh milk) are heated to 70-90°C for sterilization and then rapidly cooled to below 4°C for refrigeration.
[0003] The technical concept behind this invention, which constructs a method and system for processing liquid products using a composite heat pump coupled with a turbulent spherical tower, is as follows: The composite heat pump uses an inert gas (relative to the solution being processed) as the working fluid, and achieves a process of extracting heat from cold and providing combined cooling and heating through a semi-closed cycle. The cycle process includes both heat exchange between the working fluid and the solution through the partition wall and direct heat and mass transfer between the working fluid and the solution. In particular, the efficient heat and mass transfer at the gas-liquid interface is achieved through the coupling of the turbulent spherical tower, allowing the solution processing and cooling / heating processes to be carried out synchronously in situ at the gas-liquid interface. This shortens the process, simplifies the equipment, enhances process efficiency, and thus improves economic benefits. For example, existing cooling technologies cannot address the issue of directly cooling (80℃→40℃) the end of a high-concentration (above 52% P2O5) phosphoric acid product production line before filling and transporting it in tanks. This invention addresses this problem by constructing a continuous processing system. An expansion-compressor unit drives the circulation of air working fluid. After the air expands, it absorbs heat directly from the 80℃ product phosphoric acid in a cold-end turbulent sphere tower at low temperature and low pressure, cooling it to below 40℃. After absorbing heat, the air is compressed, heated, and pressurized before entering the hot-end turbulent sphere tower, where it directly heats the process water, raising its temperature from 30℃ to above 85℃. This couples the cooling and heating at both ends with the solution processing process. The required driving force, i.e., the power consumption of the expansion-compressor unit (converted to a unit product), is only 10.3 kWh / ton of P2O5. This power consumption is then converted into heating at the hot end, resulting in a heat / power ratio (coefficient of performance) greater than 5.0. This indicates that the technology has a short process flow, simple equipment, and high efficiency. Summary of the Invention
[0004] This invention discloses a method and system for processing liquid products using a composite heat pump coupled with a turbulent spherical tower, as shown in the attached figure. Figure 1The illustrated heat and mass transfer cycle involves direct contact between the working fluid and the solution. Driven by the working fluid expansion / compressor unit 3, the low-temperature (0.5~8.0℃) and low-pressure (0.03~0.13MPa absolute pressure) working fluid gas from the expander outlet on the left side of the unit enters the cold-end turbulent spherical tower 1 and flows upward. It directly contacts the cold-end solution, which is uniformly distributed from the top of the tower, on the surface of the turbulent packing layer composed of hollow plastic spheres, transferring heat and vaporizing to achieve the required cooling of the cold-end solution. The heat-absorbing, heated, and humidified working fluid gas passes through the cold-end gas demister 7 to remove mist before being drawn into the compressor inlet on the right side of the working fluid expansion / compressor unit 3, where it is pressurized and heated. After reaching a temperature of <0.35MPa, <185℃, the working gas directly enters the hot-end turbulent spherical tower 2 and rises. It directly contacts the hot-end solution, which is uniformly distributed downwards from the top of the tower, on the surface of the turbulent spherical packing layer for heat transfer and vaporization, achieving the requirements of hot-end solution concentration and degassing. The heat-releasing, cooling, and humidifying working gas passes through the hot-end gas demister 8 to remove mist before entering the working gas conditioning buffer tank 4. In this tank, the working gas is conditioned according to the pressure, temperature, gas density, and water vapor concentration parameters set for the working gas circulation. This is achieved by automatically controlling the exhaust valve 5 to quantitatively release a portion of the circulating gas and simultaneously automatically controlling the replenishment valve 6 to quantitatively replenish qualified working gas. After passing through the conditioning buffer tank 4, the working gas enters the inlet of the expander on the left side of the working gas expander / compressor unit 3 (shown in the diagram) for adiabatic expansion. The coaxial output power replaces part of the externally supplied drive power of this unit. The expanded, low-temperature, low-pressure working gas then enters the cold-end turbulent spherical tower 1, thus forming a semi-closed cycle of a composite heat pump coupled turbulent spherical tower for processing liquid products, where the working gas and solution are in direct contact.
[0005] As attached Figure 2The diagram shows both direct heat and mass transfer between the working fluid and the solution, as well as a cyclical process involving heat exchange between the working fluid and the solution through a partition wall. Driven by the working fluid expansion / compressor unit 3, the low-temperature (0.5~8.0℃) and low-pressure (0.03~0.13MPa absolute pressure) working fluid gas from the outlet of the expander on its left side directly enters the cold-end turbulent spherical tower 1 and flows upward. It directly contacts the cold-end solution, which is uniformly distributed from the top of the tower, on the surface of the turbulent spherical packing layer for heat transfer and vaporization, thus achieving the cooling requirement of the cold-end solution. The working gas exiting the cold-end turbulent sphere tower 1 has a temperature not exceeding 20℃ and a humidity not exceeding 90%. It continues to flow upward as a refrigerant into the series-connected secondary cold-end turbulent sphere tower 9, where it comes into direct contact with the secondary cold-end solution that is uniformly distributed downward from the top of the tower. This direct contact and heat transfer vaporization achieves the cooling requirement for the secondary cold-end solution. The working gas exiting the secondary cold-end turbulent sphere tower 9 has a temperature not exceeding 50℃ and a humidity not exceeding 90%. After passing through the cold-end gas demister 7 to remove mist, it is drawn into the compressor inlet of the working gas expansion / compressor unit 3. It is pressurized and heated to (<0.35MPa, <185℃) and enters the working gas side of the hot-end partition heat exchanger 10 to release heat. The heat is transferred through the partition to the hot-end solution on the other side, raising its temperature. The working gas is cooled and condensed to a saturated gas with a temperature not lower than 25°C. After the condensate is separated by the hot-end gas / liquid separator 11, the working gas is then removed by the gas demister 8 and modulated to the required level by the working gas conditioning buffer tank 4. The working gas then enters the expander of the expander / compressor unit 3 for adiabatic expansion and coaxial output power to replace part of the external drive power of the unit. The expanded low-temperature and low-pressure working gas enters the cold-end turbulent sphere tower 1, thus forming a cyclic process that includes both direct heat and mass transfer between the working gas and the solution and heat exchange between the working gas and the solution through the partition wall. Attached Figure Description
[0006] Appendix Figure 1 and attached Figure 2 These are schematic diagrams of the apparatus and circulation process for processing liquid products using a composite heat pump coupled with a turbulent spherical tower, which involves direct heat and mass transfer between the working fluid and the solution, and heat exchange between the working fluid and the solution wall, as provided by this invention. (Attached) Figure 1 and attached Figure 2 middle: 1 – Cold-end turbulent sphere tower; 2 – Hot-end turbulent sphere tower; 3 – Working fluid expansion / compressor unit; 4 – Working fluid conditioning buffer tank; 5 – Automatic control exhaust valve; 6 – Automatic control make-up gas valve; 7 – Cold-end gas demister; 8 – Hot-end gas demister; 9 – Secondary cold-end turbulent sphere tower; 10 – Hot-end indirect heat exchanger; 11 – Hot-end gas / liquid separator. Detailed Implementation
[0007] The following describes specific implementations of the present invention in conjunction with, but not limited to, the embodiments.
[0008] Example 1: A wet-process phosphoric acid production plant requires 70m³ of wet-process phosphoric acid with a P2O5 concentration of 52%.3 The temperature is reduced from 80℃ to 40℃ per hour, and the heat released during cooling is recovered to supply 55.4 m³ of process makeup water to the wet-process phosphoric acid processing unit. 3 The temperature is increased from 30℃ to 85℃ per hour.
[0009] According to the appendix Figure 1 The implementation method shown directly uses air under atmospheric conditions as the heat pump working fluid for this process. The working fluid flow rate of the semi-closed cycle driven by the working fluid expansion / compressor unit 3 is 22500 Nm³, calculated as oven-dry air. 3 At a rate of / h, the working gas at a low temperature of 1~2℃ and a low pressure of 0.058~0.06MPa at the outlet of the unit's expander enters the cold-end turbulent spherical tower 1 and flows upward. It comes into direct contact with the 80℃ phosphoric acid (cold-end solution inlet) uniformly distributed from the top of the tower and undergoes heat transfer and vaporization on the surface of the turbulent packing layer composed of hollow plastic spheres. The temperature of the phosphoric acid (cold-end solution outlet) at the bottom of the tower is <40℃, which meets the process requirements. The working fluid rises at an empty tower velocity of 1.25~1.50 m / s in the turbulent sphere tower at both the cold and hot ends. The seamless hollow spheres are made of polypropylene. At the top outlet, the working fluid gas absorbs heat, increasing its temperature and humidity to 68~70℃ and 82~86%. After being demisted by the cold-end gas demister 7, it is drawn into the compressor inlet of the expansion / compressor unit 3, where it is pressurized and heated to (0.105~0.115 MPa, 140~150℃). It then directly enters the hot-end turbulent sphere tower 2, where it flows upwards and meets the 30℃ process water (hot-end solution inlet) uniformly distributed from the top of the tower. 3 The heat is released directly from the surface of the turbulent spherical packing layer. The temperature of the process water (hot end solution outlet) at the bottom of the tower reaches the required 85℃. The working gas at the top of the tower is cooled to saturated air at 42~44℃ and 0.10~0.105MPa. After the mist is removed by the hot end gas demister 8, it enters the working gas conditioning buffer tank 4, where the dry air flow rate is set to 22500Nm³ according to the working gas circulation settings. 3 The flow rate is compared with the flow rate calculated by real-time monitoring of gas pressure, temperature, density, water vapor concentration parameters in the buffer tank and unit speed. The exhaust valve 5 and the make-up gas valve 6 are automatically controlled to achieve a constant flow circulation based on the atmospheric environment. After passing through the conditioning buffer tank 4, the working gas enters the expander of the expander / compressor unit 3 for adiabatic expansion and coaxial output power of 380~420kW to reduce the power consumption of external power supply. After expansion, the working gas enters the cold end turbulent spherical tower 1 at a low temperature of 1~2℃ and a low pressure of 0.058~0.06MPa. This constitutes a composite heat pump semi-closed cycle in which the working gas and the solution are in direct contact. The expander / compressor unit 3 requires an external power supply of 600~640kW.
[0010] Compared with the prior art, the beneficial effect of this embodiment is that it uses atmospheric air as the working fluid, at 22500 Nm 3 / h (oven-dry air) adiabatically expands from 42~44℃ / 0.10~0.105MPa to 1~2℃ / 0.058~0.06MPa as a refrigerant, directly transferring heat and mass with high-concentration phosphoric acid at 80℃ to cool it to 40℃ and increase the P2O5 concentration to 54.0~54.2%, while recovering 380~420kWh of expansion power; 600~640kWh of externally supplied electricity is used to drive the compression heating cycle, turning 55.4m 3 The process makeup water is heated from 30°C to 85°C, with a coefficient of performance (heat / work ratio) of 5.7, and 4.62 t / h of condensate is recovered. Therefore, the composite heat pump coupled turbulent spherical tower combined cooling and heating technology for processing liquid products of this invention has outstanding energy, ecological, and economic benefits.
[0011] Example 2: A dairy processing plant is undergoing energy-saving and water-saving technological upgrades, requiring the establishment of a closed-loop chilled water and circulating cooling water supply station. The chilled water flow rate is 15 t / h, with a supply temperature of 2℃ and a return temperature of 15℃. The circulating cooling water flow rate is 85 t / h, with a supply temperature of 30℃ and a return temperature of 52℃. High-purity nitrogen gas meeting dairy industry hygiene standards is required as the working fluid.
[0012] According to the appendix Figure 2 The implementation method shown uses 99.99% pure nitrogen as the heat pump working fluid in this process. Exhaust valve 5 is open to the atmosphere, and make-up valve 6 is connected to a high-purity nitrogen balloon tank that maintains a pressure above 0.15 MPa. The flow rate of the semi-closed-loop working fluid driven by expansion / compressor unit 3, calculated based on absolutely dry nitrogen, is 13000 Nm³. 3At a rate of 0.5~1.0℃ and 0.038~0.042MPa, the working gas from the expander outlet enters the cold-end turbulent spherical tower 1 and flows upward. It directly contacts and vaporizes with 15t / h of 15℃ chilled water return (cold-end solution inlet) uniformly distributed from the top of the tower, causing the return water to cool down. The temperature of the water at the bottom of the tower (cold-end solution outlet) is <2℃. The working gas at the top of the tower absorbs heat, increases in temperature and humidity to 13~13.5℃ and 85~90%, and continues to flow upward in the series-connected secondary cold-end turbulent spherical tower 9 for cooling. It then directly contacts and vaporizes with 85t / h of 52℃ circulating cooling water return (secondary cold-end solution inlet) uniformly distributed from the top of tower 9, causing the return water to cool down to the temperature of the water at the bottom of the tower (secondary cold-end solution outlet). The working gas temperature is below 30℃, the outlet temperature is 48~49℃, and the humidity is 85~90%. After passing through the cold-end gas demister 7, it is drawn into the compressor inlet of the expansion / compressor unit 3, where it is pressurized and heated to 0.105~0.11MPa / 180~185℃. It then enters the working gas side of the hot-end partition heat exchanger 10 to release heat. The heat is transferred through the partition to the milk liquid (hot-end solution) flowing on the other side at a rate of 90t / h, raising its temperature from 20℃ at the inlet to 90℃ at the outlet. The working gas is then cooled and condensed to a saturated gas at 30~32℃. The condensate is separated by the hot-end gas / liquid separator 11 at a rate of 3.2~3.5t / h. The condensate is then removed by the gas demister 8 and passed through the working gas conditioning buffer tank 4 at a flow rate of 13000Nm³ of oven-dry nitrogen. 3 The expander of the expansion / compressor unit 3 undergoes adiabatic expansion upon reaching the specified h-hour threshold. Its coaxial output power of 170-190kW replaces part of the externally supplied drive power. The expanded, low-temperature, low-pressure (0.5-1.0℃ / 0.038-0.042MPa) working gas enters the cold-end turbulent spherical tower 1, thus forming a semi-closed cycle that combines direct heat and mass transfer between the working fluid and the solution with heat exchange through the partition wall. The expansion / compressor unit 3 requires an external supplementary power supply of 900-1000kW. Based on a refrigeration performance coefficient (cooling / electricity ratio) of 5.5, this translates to 41.2kW of electricity consumption for chilled water and 398kW for circulating cooling water. Therefore, the heating power allocated to milk heating does not exceed 560kW, resulting in a heating performance coefficient (heat / electricity ratio) greater than 5.6.
[0013] Compared with existing technologies, the beneficial effects of this embodiment are that the dairy processing plant uses high-purity nitrogen as a green working fluid for refrigeration, simultaneously producing 2°C chilled water and 30°C circulating cooling water without the need for a cooling tower, with a refrigeration performance coefficient of no less than 5.5. Furthermore, the heat released during the refrigeration process is recovered and raised to above 180°C for heating, with a heating performance coefficient of no less than 5.6. Therefore, the composite heat pump coupled turbulent spherical tower combined cooling and heating technology of this invention has outstanding energy, ecological, and economic benefits.
[0014] The present invention is not limited to the above embodiments, and its technical solutions have been described in the invention content section.
Claims
1. A method and system for processing liquid products using a composite heat pump coupled with a turbulent spherical tower, characterized in that: Using a gas that is relatively inert to liquid products as the heat pump working fluid, heat extraction from cold and combined cooling / heating are achieved through a semi-closed cycle; The semi-closed cycle includes both the heat exchange process between the working fluid and the solution through the partition wall and the heat and mass transfer process between the working fluid gas and the solution through direct contact. In particular, it uses a turbulent sphere tower to couple the gas-liquid two-phase interface for efficient heat and mass transfer, so that the solution processing and cooling / heating processes can be carried out synchronously in situ at the gas-liquid interface. The upward air velocity inside the turbulent sphere tower is 1.25~1.50m / s, and the turbulent sphere is a seamless hollow sphere made of polypropylene.
2. The method and system for processing liquid products using a composite heat pump coupled turbulent spherical tower according to claim 1, characterized in that: The working fluid circulation is driven by an expander / compressor unit. The working fluid is adiabatically expanded and coaxially output power through the expander of this unit. The working fluid gas expands and cools down to 0.5~8.0℃ and depressurizes to 0.03~0.13MPa before entering the cold end turbulent sphere tower. It directly contacts the cold end solution, which is uniformly distributed from the top of the tower, on the surface of the turbulent sphere packing layer, causing the solution to vaporize and cool down, thus achieving refrigeration. After the working fluid gas is heated and humidified and the mist is removed, it is drawn into the compressor, pressurized to <0.35MPa, and heated to <185℃ before directly entering the hot end turbulent sphere tower. It directly contacts the hot end solution, which is uniformly distributed from the top of the tower, on the surface of the turbulent sphere packing layer, heating the solution and causing the solution to vaporize, concentrate, and degas. All of these are heat and mass transfer processes that involve direct contact with the solution. After being pressurized and heated, the working gas gas in the hot-end partition heat exchanger releases heat, and the heat is transferred to the hot-end solution on the other side through the partition wall, which raises its temperature. This is a non-direct contact partition heat exchange. The working gas that directly contacts the heat release, cooling and humidification process is directly de-misted by the hot end gas demister. The working gas that is cooled and condensed by the partition heat exchanger is first separated into condensate and then enters the demister for gas de-mist removal. After the working gas is de-foamed, it is conditioned in a working gas conditioning buffer tank. The method is to control the opening and closing of the exhaust valve and the gas supply valve online to achieve constant flow circulation by comparing the set dry working gas circulation flow rate with the flow rate calculated by real-time monitoring of the gas pressure, temperature, density, water vapor concentration and speed of the expansion / compressor unit in the buffer tank. When air is used as the working medium, the circulating gas is directly discharged through automatic control and quantitative release, and the gas replenishment valve is automatically connected to the atmosphere; when high-purity nitrogen that meets food hygiene standards is used as the working medium, the gas replenishment valve is automatically connected to the high-purity nitrogen balloon tank that always maintains a pressure of above 0.15MPa.
3. The method and system for processing liquid products using a composite heat pump coupled with a turbulent spherical tower according to claim 1, characterized in that: The working gas exiting the cold-end turbulent sphere tower has a temperature not exceeding 20℃ and a humidity not exceeding 90%. It continues to be used as a refrigerant in the series-connected secondary cold-end turbulent sphere tower, where it comes into direct contact with the secondary cold-end solution again for heat transfer and vaporization to meet the cooling requirements of the secondary cold-end solution. The working gas temperature rises to not more than 50℃ and the humidity not more than 90%. After removing the mist and increasing the pressure and temperature, it enters the hot end to release heat.