CN114100165A

CN114100165A - Multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling temperature

Info

Publication number: CN114100165A
Application number: CN202111633285.9A
Authority: CN
Inventors: 李爱松
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-12-29
Filing date: 2021-12-29
Publication date: 2022-03-01

Abstract

The invention belongs to the field of industrial processes, energy and environmental protection, and particularly relates to a low-temperature evaporation and concentration system of a multi-energy cascade utilization heat pump, which can accurately control temperature. The invention discloses a multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling temperature, which comprises a heating tank, a steam cooling and condensing system, a heat pump circulating system, a vacuumizing and recondensing system, a water circulation temperature adjusting system, a heat radiating system and a material preheating system. The system can realize high-efficiency heat exchange at the refrigerant side, improve the pressure environment of the material heating coil, effectively solve the problem of inconvenience caused by heating materials by the high-temperature refrigerant, improve the material treatment quality, and simultaneously reduce the superheat degree of secondary steam and improve the heat exchange environment at the evaporator side during initial starting. The system can accurately control the boiling evaporation temperature of the material and efficiently utilize the boiling evaporation temperature according to the grade of energy, achieves the aims of saving energy and reducing carbon, and is very significant.

Description

Multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling temperature

Technical Field

The invention belongs to the field of industrial processes, energy and environmental protection, and particularly relates to a low-temperature evaporation and concentration system of a multi-energy cascade utilization heat pump, which can accurately control temperature.

Background

Energy and environmental issues have become increasingly prominent in industrial production, which puts higher demands on energy saving technology. In particular, the proposal of the double-carbon target puts forward a new target requirement for energy conservation and carbon reduction in the industrial field. In the industrial field, evaporation and concentration are very common material heat treatment processes and are also important links of energy consumption and carbon emission, and the adoption of an energy-saving and carbon-reducing technology in the process has important significance for energy and environmental protection.

In the evaporation concentration process, the problem of evaporation concentration of heat-sensitive materials or special waste water and waste liquid is frequently encountered, and the materials have a plurality of problems when the temperature is too high. For example, the active ingredients can be denatured to affect quality, and the active ingredients are adhered to the evaporation wall or coked to affect heat transfer; the secondary steam carries excessive other impurity components, and does not meet the requirements of the process or environmental protection and the like; the boiling evaporation temperature of the material solution is an important regulation condition during evaporation and concentration, an accurate and stable heating temperature control means is needed, and the requirements of efficient heat exchange and energy conservation are met; some materials can achieve the aim of recycling after keeping the original solute character through temperature-controlled evaporation, thereby realizing green environmental protection and preventing secondary pollution. Meanwhile, some materials with higher viscosity or poor fluidity cannot adopt an enhanced evaporation measure of falling film or system circulation injection, and the problems of enhanced heat transfer and material adhesion reduction in the partition wall type heat exchange are also considered, and the problems are also greatly related to the control of evaporation temperature and the selection of a heat transfer mode.

The vacuum low-temperature evaporation and concentration system adopting the reverse Carnot cycle heat pump has low material evaporation operation temperature and is more suitable for evaporation of heat-sensitive materials or special waste water and waste liquid. The adoption of the reverse Carnot cycle involves core components such as a compressor, a refrigerant, a condenser, an evaporator and the like. In the existing vacuum low-temperature evaporation concentration system adopting a reverse Carnot cycle heat pump, a material heating side (condenser side) generally adopts a refrigerant to directly enter a part exchanging heat with a material partition wall, and the method has a plurality of technical problems: (1) the temperature of the gaseous refrigerant at the outlet of the compressor in the heat pump circulation process is very high and fluctuates greatly, and if the gaseous refrigerant is directly introduced into the heat exchange component, the material on the evaporation surface at the inlet of the heat exchange component is instantaneously overtemperature denatured or excessively evaporated and bonded to influence heat transfer. If the heat dissipation part is additionally arranged on the outlet pipeline of the compressor for cooling, the available heat for heating the material is reduced, the electricity consumption of cooling and heat exchange is increased, and meanwhile, the problem of poor temperature controllability of pre-cooling the gaseous refrigerant is also caused, so that the temperature fluctuation of a refrigerant inlet for exchanging heat with the material is increased, and the temperature cannot be accurately controlled; (2) in the sensible heat cooling process before the condensation of the high-temperature gaseous refrigerant and the sensible heat supercooling process of the liquid refrigerant, the mode of exchanging heat with the inner wall surface of a heating tank coil or a sleeve is adopted, the heat transfer effect is poorer than that of a plate heat exchanger, the heat transfer area of the coil or the wall surface of the sleeve needs to be increased, the capacity of the materials in an evaporation tank is occupied by squeezing, the side resistance or the flow of a condenser can be increased, and the exhaust temperature of the compressor is further increased. (3) The measures or poor effect of the measures for enhancing heat exchange at the feed liquid side of the heat-sensitive material or the special waste water and waste liquid are not considered, so that the heat driving force of overflowing steam in the material is insufficient, the evaporation heat transfer is blocked, the heating temperature is far higher than the boiling point, the steam superheat degree is higher, the condensation load of the steam at the rear section is increased, more foams are formed due to excessive boiling, the dryness of the steam is influenced, and the energy consumption of equipment operation is increased. (4) Because the condensation heat-releasing side contains the heat generated by the compressor, in order to keep the cold-heat balance of the heat pump cycle, the general method is to additionally arrange an air cooling heat-dissipating device in front of the throttle valve to discharge the part of heat (so that the heat pump cycle is changed into a refrigeration cycle) and improve the supercooling degree before throttling, and the part of heat is not utilized to become heat loss, so that the system energy efficiency is reduced. (5) The refrigerant side of the condenser is at high pressure, the material side is at high vacuum, the pressure difference between the two sides of the heat exchange wall surface is very large when the condenser and the material side are directly subjected to wall heat exchange, the requirements on materials and processing are very high, and the cost and the refrigerant leakage risk are increased.

The main technical problems of the existing heat pump vacuum low-temperature evaporation concentration system on the steam condensation side (evaporator side) include: (1) the traditional heat exchange coil or finned tube has low heat exchange efficiency, so that the evaporation temperature is far lower than the steam condensation temperature, and the system energy efficiency is reduced. Meanwhile, when the secondary steam generation amount is large, the vacuum degree in the device is reduced due to the fact that condensation heat exchange is not timely carried out, and the operation energy consumption of the vacuum pumping equipment is increased; (2) in the process of initial starting material temperature rise in the traditional process, because of non-boiling evaporation, a heat exchange component is not in steam contact, so that the working condition of a refrigeration cycle is worsened. (3) The problem of gradient heat energy grade is not considered in the prior art, because the steam temperature is high, the temperature gradient between the steam condensation temperature and the refrigerant evaporation temperature is large, gradient condensation cannot be realized by a single refrigerant cooling mode, and the energy efficiency of a system is reduced; (4) the existing heat pump vacuum low-temperature evaporation concentration technology does not fully consider the adoption of a high-efficiency secondary steam condensation heat exchange mode, so that the evaporation temperature is low, and the energy efficiency of a heat pump circulating system is low.

In summary, in the improvement of the existing heat pump low-temperature evaporation concentration system, three technical problems of meeting the process treatment temperature requirement, improving the heat pump heating energy efficiency and reducing the energy consumption level of the whole system need to be considered.

The system is high in controllability of material heating temperature, stable in evaporation, good in heat transfer effect of a heat exchange part, high in steam condensation efficiency, low in operation energy consumption, capable of fully utilizing heat produced by a compressor and efficiently removing redundant steam heat, low in maintenance cost, long in service life, and capable of improving system energy efficiency by effectively utilizing waste heat or renewable energy sources, natural cold sources and other energy sources at different grades, and is particularly suitable for concentration recovery of heat-sensitive solutions and special waste water and waste liquid. The system can realize high-efficiency heat exchange at the refrigerant side, improve the pressure environment of the material heating coil, effectively solve the unfavorable problems caused by heating materials by high-temperature refrigerants, improve the quality of steam condensate, reduce the superheat degree of secondary steam, improve the evaporation temperature and improve the heat exchange environment at the evaporator side during initial starting. The system can achieve the purposes of energy conservation, emission reduction and carbon reduction, and is very significant.

Disclosure of Invention

The invention aims to solve the problems and the defects in the prior art, and provides a multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling temperature.

According to the application, the system can accurately control the temperature and can utilize the heat pump low-temperature evaporation concentration system in a cascade way, wherein the system comprises a heating tank, a steam cooling and condensing system, a heat pump circulating system, a vacuumizing and re-condensing system, a water circulation temperature adjusting system and a heat radiating system,

a stirring motor is arranged above the outside of the heating tank, a fan blade, a defoaming device and a stirring blade are arranged in the heating tank, a concentrated material liquid outlet pipe is arranged at the bottom of the heating tank, the stirring motor provides power for the rotation of the stirring blade and the fan blade, and a heat insulation layer is arranged on the outer wall of the heating tank;

the steam cooling and condensing system comprises a cold water circulating tank, a steam-water heat exchanger, a spray water circulating pump and a liquid sprayer, wherein the steam-water heat exchanger is arranged on a steam flow pipeline and used for pre-cooling steam, the liquid sprayer is arranged in the cold water circulating tank and used for condensing and absorbing steam, the spray water circulating pump is used for providing power for cold water circulation, and the cold water circulating tank is used for storing circulating cold water;

the heat pump circulating system comprises a compressor, a primary heat exchanger, a refrigerant heating coil, a throttling valve, an evaporator coil, a secondary evaporator and a refrigerant gas-liquid separator, wherein the compressor provides power for heat pump circulation, the primary heat exchanger exchanges heat with the water circulation temperature regulating system, the refrigerant heating coil is arranged in the heating tank and used for heating materials, and the evaporator coil is arranged in the cold water circulating tank and used for cooling spray water and circulating cold water and further falling film to absorb steam;

the water circulation temperature regulating system comprises a hot water circulating pump, a heating pipe temperature regulating device, a hot water heating coil, an expansion tank and a water supplementing pipe, wherein the hot water heating coil is arranged inside the heating tank and used for heating materials, and the expansion tank and the water supplementing pipe are used for constant pressure and water supplementation of the water circulation temperature regulating system;

the vacuumizing and recondensing system is used for forming negative pressure so as to suck condensed water and non-condensable gas in the cold water circulating tank and ensure the vacuum environment and the condensed water level in the heating tank;

the heat dissipation system comprises evaporation cooling equipment, a cooling water pump and a cooling water temperature control device, and is used for pre-cooling and dissipating heat of secondary steam evaporated by the heating tank so as to ensure the cold-heat balance of the heat pump circulation system, the evaporation cooling equipment adopts a circulating water direct evaporation cooling mode, the cooling water pump provides cooling water circulation power, and the cooling water temperature control device is used for controlling the water inlet temperature of the steam-water heat exchanger when outdoor meteorological conditions change so as to control the heat dissipation capacity of the steam-water heat exchanger;

wherein the content of the first and second substances,

the heating tank is used for storing the dilute material subjected to boiling evaporation, the dilute material fed into the heating tank is heated to the boiling point under the vacuum condition obtained by the vacuumizing and recondensing system to start boiling evaporation, in the heating process, the stirring motor rotates to drive the stirring sheet to continuously stir the feed liquid, the generated steam is purified by the defoaming device, and the fan blades enhance the discharge power;

the steam purified in the heating tank is pre-cooled and radiated by a steam-water heat exchanger of the steam cooling and condensing system so as to ensure heat balance;

the cooled steam is absorbed by spray water formed by a liquid sprayer in a steam cooling and condensing system, is further subjected to falling film absorption and cooling by the evaporator coil to form low-temperature condensed water, and is stored in the cold water circulating tank for circulating spraying;

high-temperature and high-pressure refrigerant at the outlet of the compressor in the heat pump circulating system firstly enters the primary heat exchanger for precooling, the cooled refrigerant enters the refrigerant heating coil in the heating tank again for heating materials, then is throttled by a throttle valve and then is sent into the evaporator coil in the cold water circulating tank, and then is further absorbed by a secondary evaporator and returns to the compressor;

the hot water circulating pump of the water circulation temperature adjusting system sends circulating water into the primary heat exchanger for heating, the circulating water is sent into a hot water heating coil in the heating tank for heating liquid after being heated, and the heating pipe temperature adjusting device adjusts the flow of circulating hot water to control the inlet temperature of the refrigerant heating coil by monitoring the inlet temperature of the refrigerant heating coil;

cooling water with the temperature lower than the steam temperature generated by evaporative cooling equipment arranged in the heat dissipation system is sent into the steam-water heat exchanger through the cooling water pump, and the heat dissipation capacity is adjusted through the cooling water temperature control device.

According to the application, the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature is characterized in that a steam-water heat exchanger of the steam cooling and condensing system is a low-resistance shell and tube heat exchanger or a finned tube heat exchanger, and a steam pipeline at the outlet of the heat exchanger is connected with a cold water circulating tank.

According to the application, the multi-energy cascade that can accurate accuse temperature utilizes heat pump low temperature evaporation concentration system, wherein, spray water circulating pump wet return is connected the bottom of cold water circulating tank, go out water piping connection the sprayer, the sprayer forms spray water, and direct contact condensation absorbs vapor.

According to the application, the heat pump low-temperature evaporation concentration system is utilized to multipotency cascade of accurate temperature control, wherein, the fire fighting equipment sets up between material liquid level and fan blade.

According to the application, the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature is characterized in that the refrigerant heating coil and the evaporator coil adopt inner ribbed pipes for enhancing heat exchange in the pipes.

According to the application, the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature further comprises a material preheating system, wherein the material preheating system comprises a thin stock solution preheating tank, a preheating coil, a preheating system expansion tank, a preheating circulating pump, a solar heat collector or a waste heat exchanger, a preheating pipe temperature control device, a preheating tank vent, a thin stock solution pump and a thin stock solution inlet pipe.

According to the application, the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature comprises a vacuumizing circulating pump, a liquid blocking baffle, a vacuum ejector, a porous pipe and a water storage tank, wherein the liquid blocking baffle is arranged at a suction inlet of the vacuumizing pipe and used for preventing spray water from being sucked, the porous pipe is arranged in the water storage tank and submerged in water, the vacuumizing circulating pump presses high-flow-rate cold water into the vacuum ejector to form negative pressure for sucking condensed water and non-condensable gas in the cold water circulating tank and flows into the water storage tank through the porous pipe so as to ensure the vacuum environment and the condensed water level in the heating tank, the porous pipe is arranged in the water storage tank and submerged in circulating cold water, the water storage tank is simultaneously used for collecting overflowed condensed water, and the vacuumizing circulating pump simultaneously sends part of circulating water into a secondary evaporator for heat exchange, the heat absorption capacity of the heat pump circulating system is increased while the heat of the water storage tank is dissipated.

According to the application, but heat pump low temperature evaporation concentration system is utilized to many ability steps of accurate temperature control, wherein, the branch of vacuum ejector connects evacuation pipeline, vacuum ejector's play water piping connection porous pipe, the bottom of porous pipe is sealed, is provided with a plurality of efflux round holes all around, porous pipe set up in the aquatic of water storage tank.

The technical scheme of the application has the advantages that:

1. the solution is pretreated by solar hot water or waste heat, so that the energy efficiency of the system can be improved while energy is saved and carbon is reduced, and the treatment time of a low-temperature evaporation concentration system is reduced; the heated evaporation of material has two stage processes of sensible heat rising temperature and constant temperature boiling evaporation, and the heat transfer efficiency of the latter is showing and is greater than the former to high-efficient heat transfer in guaranteeing the heating jar, take the sensible heat that carries out the material preheating outside the heating jar to heat up the preliminary treatment, make the material that gets into the heating jar directly carry out constant temperature boiling evaporation, improved heating coil's heat transfer efficiency, reduced the condensing temperature, it is crucial to the lift system efficiency. Meanwhile, the heating capacity is derived from free heat energy, and can be obtained only by consuming a small amount of electric energy, so that the effects of energy conservation and carbon reduction are achieved.

2. The heating tank is provided with the stirring motor and the stirring sheet, and the rotation of the stirring sheet enhances the heat transfer effect of the material and the heating coil pipe on one hand, can discharge steam generated by boiling in time on the other hand, and simultaneously reduces the possibility of material adhesion or coking; the fan blades coaxial with the stirring blades rotate to improve the driving force of steam flow, so that the flow resistance is overcome to a greater extent, and the vacuum pressure in the heating pipe is ensured; a defoaming device is arranged for separating the material liquid drops, drying the steam and improving the quality of the steam.

3. Set up the primary cooling that vapour water heat exchanger was used for steam on the outlet pipeline of steam to discharge the unnecessary heat of compressor and other heat production parts, guarantee heat pump cycle's cold and hot balance, compare and set up the mode of heat extraction fan behind the condenser among the prior art, increased the heat of material heating, can produce more steam.

4. The condensation end of the heat pump circulating system adopts a two-stage heat exchange mode of a primary heat exchanger and a refrigerant heating coil, the primary heat exchanger reduces the temperature of the refrigerant entering the refrigerant heating coil without losing heat through a heat exchange mode of circulating hot water and a high-temperature high-pressure gaseous refrigerant, and the refrigerant heating coil and an evaporator coil adopt inner ribbed tubes for enhancing heat exchange in the tubes, so that the heat transfer efficiency is improved;

5. the water circulation temperature adjusting system is arranged, after the primary heat exchanger and the high-temperature high-pressure gaseous refrigerant of the compressor exhaust pipe exchange heat and rise temperature, the dilute material in the tank is heated through the hot water heating coil, and meanwhile, the heating pipe temperature adjusting device controls the refrigerant inlet temperature of the refrigerant heating coil by adjusting the flow of circulating hot water;

6. the high-efficiency heat and mass transfer mode that cold spray water directly contacts with the cooling water to condense and absorb water vapor and the cooling water of the spray evaporator coil absorbs steam in a falling film mode is adopted, and compared with indirect condensation of the steam on the wall surface of the coil, the high-efficiency heat transfer device greatly improves condensing and heat exchange efficiency, so that the circulating evaporation temperature of a heat pump can be increased, and the heating energy efficiency of the heat pump is increased. Meanwhile, the water vapor is efficiently absorbed for condensation, so that the pumping load of the vacuum pumping system is reduced, and the energy conservation of the vacuum pumping system is facilitated.

7. The heat dissipation system adopts the evaporative cooling equipment to pre-cool the secondary steam evaporated from the heating tank, so that the cold and heat balance of the heat pump circulation system is ensured, and meanwhile, the evaporative cooling natural cold source is fully utilized according to the temperature characteristics of the secondary steam, so that the heat dissipation system has the advantages of high efficiency and energy conservation.

8. The vacuumizing and recondensing system adopts a discharge mode that a porous pipe is arranged in the water storage tank, excess secondary steam is further efficiently condensed, meanwhile, the circulating heat exchange of the secondary evaporator is combined, the low temperature of the water storage tank is maintained, the vacuumizing circulating pump and the excess steam condensation heat can be recovered, the suction temperature of a compressor is increased, and the heating energy efficiency of a heat pump is further improved.

9. The utility model provides a but concentrated system of multipotency cascade utilization heat pump low temperature evaporation of accurate temperature control has organically combined multiple promotion heat transfer effect and energy utilization level's technical measure under the prerequisite of the operation condition adaptability of guaranteeing the material processing, compares with current patent technology, and great degree has promoted the efficiency level, has practiced thrift the operation energy consumption, has very big popularization prospect.

Drawings

FIG. 1 is a schematic structural diagram of a multi-energy cascade heat pump low-temperature evaporation concentration system capable of accurately controlling temperature according to the present invention;

reference numerals:

1: heating tank, 11: stirring motor, 12: defoaming device, 13: stirring blade, 14: fan blade, 15: a concentrated feed liquid outlet pipe is arranged on the upper part of the furnace,

2: cold water circulation tank, 21: steam-water heat exchanger, 22: spray water circulation pump, 23: liquid sprayer, 24: automatic water drainage interlocking mechanism

3: compressor, 31: primary heat exchanger, 32: refrigerant heating coil, 33: throttle valve, 34: evaporator coil, 35, secondary evaporator, 36: a gas-liquid separator for the refrigerant,

4: hot water circulation pump, 41: heating pipe temperature adjusting device, 42: hot water heating coil, 43: expansion tank, 44: a water-replenishing pipe is arranged on the water tank,

5: evacuation circulation pump, 51: liquid-blocking baffle, 52: vacuum ejector, 53: perforated pipe, 54: water storage tank, 6: evaporative cooling apparatus, 61: cooling water pump, 62: a temperature control device for cooling water is arranged,

7: diluent preheating tank, 71: preheating coil, 72: preheat system expansion tank, 73: preheating circulation pump, 74: solar collector, 75: preheat tube temperature control device, 76: preheating tank vent port, 77: diluent pump, 78: the thin material liquid is fed into the pipe,

8. and (7) an insulating layer.

Detailed Description

The technical solution of the present application is described in detail below with reference to specific examples.

The invention relates to a multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling temperature, which comprises a heating tank, a steam cooling and condensing system, a heat pump circulating system, a vacuumizing and recondensing system, a water circulation temperature adjusting system, a heat radiation system and a material preheating system, wherein,

a stirring motor is arranged above the outside of the heating tank, a fan blade, a defoaming device and a stirring blade are arranged in the heating tank, a concentrated liquid outlet pipe is arranged at the bottom of the heating tank, the stirring motor provides power for the rotation of the stirring blade and the fan blade, and a heat insulation layer is arranged on the heating tank;

the steam cooling and condensing system comprises a cold water circulating tank, a steam-water heat exchanger, a spray water circulating pump and a liquid sprayer, wherein the steam-water heat exchanger on a steam flow pipeline is used for pre-cooling steam, the liquid sprayer arranged in the cold water circulating tank is used for spraying cold water to directly contact and condense to absorb the steam, the spray water circulating pump is used for providing power for cold water circulation, and the cold water circulating tank is used for storing circulating cold water;

the heat pump circulating system comprises a compressor, a primary heat exchanger, a refrigerant heating coil, a throttling valve, an evaporator coil, a secondary evaporator and a refrigerant gas-liquid separator, wherein the compressor provides power for heat pump circulation, the primary heat exchanger exchanges heat with the water circulation temperature regulating system, the refrigerant heating coil is used for heating materials, and the evaporator coil is used for cooling spray water and circulating cold water and further absorbing steam in a falling film manner;

the water circulation temperature regulating system comprises a hot water circulating pump, a heating pipe temperature regulating device, a hot water heating coil, an expansion tank and a water supplementing pipe, wherein the hot water heating coil is arranged in the heating tank and used for heating materials, and the expansion tank and the water supplementing pipe are used for constant pressure and water supplementation of the water circulation temperature regulating system;

the vacuumizing and recondensing system comprises a vacuumizing circulating pump, a liquid blocking baffle, a vacuum ejector, a porous pipe and a water storage tank, wherein the liquid blocking baffle is arranged at a suction inlet of the vacuumizing pipe and used for preventing the water from being sucked into the film falling water;

the heat dissipation system comprises evaporation cooling equipment, a cooling water pump and a cooling water temperature control device, and is used for pre-cooling and dissipating heat of secondary steam evaporated from a heating tank so as to ensure the cold-heat balance of the heat pump circulation system, the evaporation cooling equipment adopts a circulating water direct evaporation cooling mode, the cooling water pump provides cooling water circulation power, and the cooling water temperature control device is used for controlling the water inlet temperature of the steam-water heat exchanger when outdoor meteorological conditions change so as to control the heat dissipation capacity of the steam-water heat exchanger;

the material preheating system comprises a thin material liquid preheating tank, a preheating coil, a preheating system expansion tank, a preheating circulating pump, a solar heat collector or waste heat exchanger, a preheating pipe temperature control device, a preheating tank air vent, a thin material liquid pump and a thin material liquid inlet pipe. The heat produced by the solar heat collector or the waste heat exchanger is heated by the preheating circulating pump through the preheating coil pipe to the dilute liquid stored in the dilute liquid preheating tank, so that the dilute liquid is heated to the boiling point during low-temperature evaporation and then is fed into the charging tank. The system is used for reducing the supercooling degree of the material entering the heating tank, reducing the sensible heat warming process of the material in the heating tank, boiling and evaporating the dilute material as soon as possible after the dilute material enters the heating tank, and improving the heating efficiency.

Wherein the content of the first and second substances,

the steam purified in the heating tank is pre-cooled and radiated by a steam-water heat exchanger of a steam cooling and condensing system so as to ensure heat balance;

the cooled steam is absorbed by spray water formed by a liquid sprayer in a steam cooling and condensing system, is further subjected to falling film absorption and cooling by an evaporator coil to form low-temperature condensed water, and is stored in a cold water circulating tank for circulating spraying.

The vacuumizing circulating pump presses high-flow-rate cold water into the vacuum ejector to form negative pressure to suck non-condensable gases such as excess steam, condensed water and air in the cold water circulating tank and to jet the non-condensable gases into the water storage tank through the porous pipe so as to ensure the vacuum environment and the condensed water level in the heating tank, the porous pipe is arranged in the water storage tank and is immersed in the circulating cold water, and the water storage tank is used for collecting the overflowed excess condensed water. The vacuumizing circulating pump sends part of circulating water into the secondary evaporator for heat exchange, and the heat absorption capacity of the circulating system of the heat pump is increased while the water storage tank is cooled.

High-temperature and high-pressure refrigerant at the outlet of the compressor in the heat pump circulating system firstly enters the primary heat exchanger for precooling, the cooled refrigerant enters the refrigerant heating coil in the heating tank again for heating materials, then is throttled by a throttle valve and then is sent into the evaporator coil in the cold water circulating tank, and then is further absorbed by the secondary evaporator and returns to the compressor.

The hot water circulating pump of the water circulation temperature adjusting system sends circulating water into the primary heat exchanger for heating, the circulating water is heated and then sent into the hot water heating coil in the heating tank for heating liquid, and the heating pipe temperature adjusting device adjusts the flow of circulating hot water to control the inlet temperature of the refrigerant heating coil by monitoring the inlet temperature of the refrigerant heating coil.

According to the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature, a refrigerant heating coil is arranged inside the heating tank.

According to the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature, the cooling water with the temperature lower than the steam temperature, which is generated by evaporation cooling equipment arranged in the heat dissipation system, is sent into the steam-water heat exchanger through the cooling water pump, and the heat dissipation capacity can be adjusted through the cooling water temperature control device.

According to the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature, the water circulation temperature adjusting system can adapt to the exhaust temperature change of the compressor and accurately control the condensation heating temperature.

According to the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature, disclosed by the invention, a water return pipe of the spray water circulating pump is connected with the bottom of the cold water circulating tank, a water outlet pipe of the spray water circulating pump is connected with the liquid sprayer, and the liquid sprayer can form spray water and directly contact with condensation to absorb water vapor.

According to the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature, the evaporator coil is arranged inside the cold water circulating tank and can form a falling film.

The invention relates to a multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling temperature, wherein a branch of a vacuum ejector is connected with a vacuum pumping pipeline, and a water outlet pipe of the vacuum ejector is connected with a porous pipe. The bottom of the porous pipe is closed, a plurality of jet flow round holes are formed in the periphery of the porous pipe, and the porous pipe is arranged in the water of the water storage tank.

According to the multi-energy cascade utilization heat pump low-temperature evaporation and concentration system capable of accurately controlling the temperature, the branch pipe is arranged at the outlet pipe of the vacuumizing circulating pump and connected with the secondary evaporator, and the cold water outlet of the secondary evaporator is sent into the water storage tank.

According to the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature, the defoaming device is arranged at the upper end of the liquid level of the material and below the fan blades, the joint of the shaft and the heating tank is well sealed, and the bottom of the heating tank is provided with the concentrated material liquid outlet pipe.

According to the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature, the refrigerant heating coil and the evaporator coil adopt inner ribbed pipes for enhancing heat exchange in the pipes.

The invention discloses a multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling temperature, and further comprises a material preheating system.

According to the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature, the material preheating system pretreats the dilute material by using the heat source provided by the solar heat collector or the waste heat exchanger. The dilute material can also be directly heated by a hot water heating coil and a refrigerant heating coil in the heating tank without passing through a material preheating system, but the mode can increase the electricity consumption and the material treatment time.

The heated evaporation of the material has two stages of sensible heat temperature rise and constant temperature boiling evaporation, and the heat transfer efficiency of the latter is obviously greater than that of the former, so that the sensible heat temperature rise pretreatment of preheating the material outside the heating tank is adopted to ensure the high-efficiency heat exchange in the heating tank, so that the material entering the heating tank is directly subjected to constant temperature boiling evaporation, and the energy efficiency of a lifting system is very important. The dilute liquid preheating tank is internally provided with a preheating coil pipe, the dilute liquid is heated to the boiling point temperature of the heating tank under the designed vacuum degree through the heat generated by the solar heat collector or the waste heat exchanger by the hot water circulating pump and is sent into the heating tank through the dilute liquid pump, and the concentrated liquid is discharged from the heating tank through the concentrated liquid outlet pipe. The preheating pipe temperature control device is used for controlling the water inlet temperature of the preheating coil pipe so as to prevent overhigh temperature.

The invention discloses a precise temperature-controllable multi-energy cascade utilization heat pump low-temperature evaporation concentration system, which is described in detail below with reference to the accompanying drawings.

As shown in fig. 1, the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling temperature comprises a heating tank, a steam cooling and condensing system, a heat pump circulating system, a vacuumizing and re-condensing system, a water circulation temperature adjusting system, a heat radiation system and a material preheating system.

Before evaporation and concentration, the material is preheated by a material preheating system to reach the boiling point temperature of the heating tank 1 under the designed vacuum degree, the preheating treatment can utilize a heat source provided by a solar heat collector 74, the material is heated to reach the set temperature through hot water circulation in a preheating coil 71 in a dilute liquid preheating tank 7 and is sent into the heating tank 1 through a dilute liquid pump 77, and a preheating pipe temperature control device 75 is used for controlling the water inlet temperature of the preheating coil 71 so as to prevent the temperature from being too high. The concentrated feed liquid is discharged through a feed liquid outlet pipe 15. The solar collector may be replaced by a waste heat exchanger.

The dilute material sent into the heating tank 1 is further heated to a boiling point through the hot water heating coil 42 and the refrigerant heating coil 32 to start boiling evaporation under the condition that a vacuum pumping and recondensing system obtains vacuum, in the heating process, the stirring motor 11 rotates and drives the stirring sheet 13 to continuously stir the feed liquid, the bonding and coking are reduced while the heat exchange and the steam escape are enhanced, the generated steam is purified by the defoaming device 12, the exhaust power is enhanced by the fan blades 14, and the steam is discharged into the steam-water heat exchanger 21 to be precooled.

The temperature of the generated steam is reduced after being pre-cooled by the steam-water heat exchanger 21, partial condensed water is generated, the steam is sprayed by a liquid sprayer 23 arranged in the cold water circulating tank 2, is directly contacted with cold water for condensation and absorption, is sprayed to an evaporator coil 34, is stored at the lower part of the cold water circulating tank 2 after being cooled by falling films and re-absorbed, and the spray water circulating pump 22 provides spray water circulating power. Before the system is operated, the cold water circulation tank 2 should first be filled with tap water to ensure that the evaporator coil 34 can be cooled.

The high-temperature high-pressure refrigerant at the outlet of the compressor 3 in the heat pump circulating system firstly enters the primary heat exchanger 31, is pre-cooled by circulating hot water, and then enters the refrigerant heating coil 32 to heat materials, and then is sent into the evaporator coil 34 in the cold water circulating tank 2 to cool circulating cold water after being throttled by the throttle valve 33. The refrigerant heating coil 32 is immersed in the material of the heating tank 1. Preferably, the refrigerant heating coil 32 and the evaporator coil 34 employ internal ribs within the tubes to enhance heat exchange.

In the water circulation temperature adjusting system, softened circulating water supplemented before the system operates enters a hot water heating coil 42 through a hot water circulating pump 4 to heat dilute materials in a hot tank 1 after the circulating water exchanges heat with a high-temperature high-pressure gaseous refrigerant of a compressor exhaust pipe through a primary heat exchanger 31 and is heated, a heating pipe temperature adjusting device 41 controls the refrigerant inlet temperature of the refrigerant heating coil 32 by adjusting the flow rate of circulating hot water, and softened water is charged through a water supplementing pipe 44 before the system initially operates to prevent the heat transfer effect from being influenced by the scaling of the hot water heating coil 42 and the primary heat exchanger 31. The hot water circulating pump 4 sends circulating water to the water side of the primary heat exchanger 31, an outlet pipeline is sent to the hot water heating coil 42 after being subjected to temperature regulation by the heating pipe temperature regulating device 41, and is connected with a suction inlet of the hot water circulating pump 4 after passing through an expansion tank 43. The water replenishing pipe 44 is connected to a return pipe of the hot water circulating pump 4.

The remaining non-condensable gases such as steam, air and the like and the surplus condensed water after being treated by the cold water circulating tank 2 are discharged through a vacuumizing and recondensing system, the vacuumizing circulating pump 5 pumps cooling water in the water storage tank 54, one part of the cooling water is pumped by the vacuum ejector 52 and then is discharged into the water storage tank 54 through the porous pipe 53, and the other part of the cooling water is sent into the secondary evaporator 35 to be cooled and heat-exchanged with the refrigerant. A liquid blocking baffle 51 is arranged at a suction inlet of a vacuum pumping pipeline of the vacuum ejector 52 to prevent the suction of spray water, and the porous pipe 53 is arranged in the water storage tank 54 and is immersed in the water for directly contacting and condensing residual steam. The water storage tank 54 is used for collecting condensed water, and before the system runs, the water level in the water storage tank 54 is ensured to be completely immersed in the porous pipe 53, so that the vacuum pumping equipment can run normally.

A cooling system cold source for soda heat exchanger 21 is refrigerated, preferentially adopts the direct evaporative cooling mode of efficient, and the secondary steam that evaporates to heating tank 1 through the cooling water that evaporative cooling equipment 6 produced precools to guarantee heat pump circulation system's cold and hot balance, when outdoor meteorological condition changes, cooling water temperature control device 62 is used for controlling the temperature of intaking of soda heat exchanger 21, in order to control its cooling capacity.

Regarding a simple reverse Carnot cycle, a heat pump cycle with temperature difference heat transfer is considered, the boiling point of water and the condensation point of steam under a vacuum condition are 40 ℃, the maximum heating coefficient of the ideal cycle of the heat pump is 10.94 when the condensation temperature of a heating pipe is 55 ℃ and the evaporation temperature of an evaporator coil is 25 ℃, the actual situation is obviously lower than that due to various losses, but the value can be used as the target of improving the energy efficiency. When the heating tank does not adopt heat exchange enhancement measures or the heat transfer condition is worsened due to scaling, the condensation temperature of the heating pipe is 60 ℃ for enabling the feed liquid to reach the boiling temperature, meanwhile, the heat exchange condition of the evaporator side is poor, and the evaporation temperature needs to be reduced to meet the requirement of the heat exchange quantity, the maximum heating coefficient of the ideal cycle of the heat pump is 7.4 at the moment according to the evaporation temperature of 15 ℃. The invention enhances the heat transfer effect of the condenser and the evaporator side to improve the heat pump circulation energy efficiency, and after the heat exchange enhancement measure is adopted, the maximum heating coefficient of the ideal circulation of the heat pump can reach 21.2 according to the condensing temperature of the heating pipe of 45 ℃, the evaporating temperature of the coil of the evaporator of 30 ℃ and the like.

Regarding the material preheating system, assuming that the specific heat of the solution is the same as that of water, 34.9kWh of energy is required for heating 2 tons of dilute solution with the initial temperature of 25 ℃ to 40 ℃, and when the heat is heated by solar hot water or waste heat, the energy consumption of the circulating water pump is considered to be 3% according to practical engineering experience, about 1.1kWh of electricity is required to be consumed, and the energy efficiency ratio of the material preheating system can reach 31.7. Meanwhile, the convection heat transfer coefficient before the heating coil of the heat pump circulating condenser is not boiled is considered to be obviously lower than that of boiling heat transfer, so that solar hot water or waste heat is adopted to preheat materials to the boiling temperature under the designed vacuum degree, free heat resources are efficiently utilized, and the heat transfer energy efficiency level in the heating tank can be obviously improved.

In the existing low-temperature evaporation concentration system, a mode that a cooling fan is arranged behind a condenser to remove redundant heat of a heat pump compressor is adopted, the heat pump cycle is actually changed into a refrigeration cycle, when the heating coefficient of the heat pump cycle is 5-10, the refrigeration cycle is only 4-9, namely 10% -20% of effective heat is lost, the heat pump cycle is not used for heating materials to generate steam, and the system energy efficiency is obviously reduced.

When the surplus heat generated by the heating of the heat pump compressor in the steam is removed, the steam can be completely cooled by adopting evaporative cooling equipment because the temperature of the steam is about 40 ℃, and the calculation is carried out by taking the condition of the existing market products as an example, a KN 8-II-1 type mechanical ventilation open cooling tower is selected, the water inlet temperature is 37 ℃, the water outlet temperature is 32 ℃, the wet bulb temperature is 28 ℃, the dry bulb temperature is 31.5 ℃, and the design water flow is 6.23m³The heat dissipation power is 36.2kW, the fan power is 0.18kW, the water pump power is 0.25kW, the energy efficiency of the heat dissipation system adopting the evaporative cooling equipment can reach 84.3 (when the outdoor wet bulb temperature and the outdoor dry bulb temperature are reduced, the energy efficiency level is further improved), and the energy efficiency is far higher than that of the heat dissipation system adopting the evaporative cooling equipmentThe cooling mode of the special attached refrigerating device is adopted.

The direct contact condensation of the steam is a condensation mode with very high heat transfer and mass transfer coefficients, which is far higher than the film condensation of a cooling wall surface, and a high-efficiency heat transfer and mass transfer mode that spraying cold water is directly contacted with the condensation absorbing water vapor and spraying evaporator coil falling films absorb the steam is adopted in a cold water circulation tank. Meanwhile, the water vapor is efficiently absorbed for condensation, so that the pumping load of the vacuum pumping system is reduced, and the energy conservation of the vacuum pumping system is facilitated.

Taking the treatment of aqueous ink wastewater as an example, 1 ton of a 40% by mass aqueous ink dilute solution at an initial treatment temperature of 20 ℃ was concentrated to 0.5 ton of a 80% by mass aqueous ink concentrated solution, and 0.5 ton of condensed water was produced. The boiling point of water under the absolute pressure of 7.4kPa (the vacuum degree is about-94 kPa) is 40 ℃, and the latent heat of vaporization is 2406 kJ/kg. The heat required to evaporate 0.5 ton of water was 334 kWh. A ZW150KBE type heat pump compressor and an R134a refrigerant are selected, and in the normal operating working condition range, the condensation temperature is 50 ℃, the evaporation temperature is 30 ℃ and the heating capacity under the working condition is 68.97kW and the input power is 8.09kW through heat exchange enhancement measures. Meanwhile, according to the technical measures of the patent, the power of a stirring motor is 2kW, the total power of evaporative cooling equipment and a cooling water pump of a heat dissipation system is 0.35kW, the power of a spray water circulating pump is 0.11kW, the power of a hot water circulating pump is 0.11kW, the power of a vacuumizing circulating pump is 0.5kW, the total operating power is 11.16kW, the time required for evaporating 0.5 ton of water is 4.84h, 54kWh of power is consumed, and in addition, the power consumption of a material preheating system is 1.1kWh, the total power consumption of the system is 55.1kWh, and the total energy efficiency ratio of the system is 6.06 (the energy efficiency is further improved when a larger system is adopted).

The low-temperature evaporation system provided by the invention adopts the heat pump as a heat source, combines steam condensation and air extraction of a vacuum device to form a certain vacuum state, and can realize boiling evaporation of a solution at about 40 ℃. Due to the adoption of the measures of stirring in the heating tank and controlling the temperature of the heating pipe, the heat exchange effect is not reduced while the heating pipe is not over-heated and the temperature is stable, so that thermosensitive materials or special waste water and waste liquid are not easy to bond and have chemical change, and convenience is provided for improving the energy efficiency and recycling. The material heating end fully utilizes the heat production quantity of the compressor, and precools steam through the high-efficiency evaporation cooling equipment to realize cold-heat balance, so that the heat quantity of the material in the heating and evaporation process is sufficient, the heat loss is small, and the energy efficiency is improved. Meanwhile, a high-efficiency heat and mass transfer mode that spraying cold water is directly contacted with condensation to absorb water vapor and spraying evaporator coil falling film to absorb steam is adopted in the cold water circulating tank, so that the steam condensation efficiency is enhanced to a greater extent and the air exhaust load of the vacuum pumping system is reduced. Furthermore, the solution is pretreated by solar hot water or waste heat, so that the evaporation and concentration time of the heat pump is shortened, the energy efficiency is improved, and the purposes of energy conservation and emission reduction are achieved. Compared with a conventional system, the multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling the temperature greatly improves the energy efficiency level of the system while ensuring the production quality of materials.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims

1. A multi-energy cascade utilization heat pump low-temperature evaporation concentration system capable of accurately controlling temperature is characterized by comprising a heating tank, a steam cooling and condensing system, a heat pump circulating system, a vacuumizing and recondensing system, a water circulation temperature adjusting system and a heat dissipation system,

wherein the content of the first and second substances,

2. The system for multi-energy cascade utilization of heat pump low-temperature evaporation concentration according to claim 1, wherein the steam-water heat exchanger of the steam cooling and condensing system is a low-resistance shell-and-tube heat exchanger or a finned-tube heat exchanger, and the outlet steam pipeline of the heat exchanger is connected with the cold water circulation tank.

3. The system of claim 1, wherein a return pipe of the spray water circulation pump is connected to a bottom of the cold water circulation tank, and an outlet pipe of the spray water circulation pump is connected to the spray unit, and the spray unit forms spray water which directly contacts with the condensation to absorb water vapor.

4. The system of claim 1, wherein the defoaming device is disposed between a material level and the fan blades.

5. The temperature-controlled, multi-energy, step-use, heat pump, cryogenic evaporative concentration system of claim 1, wherein the refrigerant heating coil and the evaporator coil are internally ribbed for enhanced heat transfer within the tube.

6. The system of claim 1, further comprising a material preheating system, wherein the material preheating system comprises a diluent preheating tank, a preheating coil, a preheating system expansion tank, a preheating circulating pump, a solar heat collector or waste heat exchanger, a preheating pipe temperature control device, a preheating tank vent, a diluent pump, and a diluent inlet pipe.

7. The system of claim 1, wherein the evacuation and recondensing system comprises an evacuation circulation pump, a liquid blocking baffle, a vacuum ejector, a porous pipe, and a water storage tank, wherein the liquid blocking baffle is disposed at a suction inlet of the evacuation pipe for preventing spray water from being sucked, the porous pipe is disposed in the water storage tank and submerged in water, the evacuation circulation pump pumps cold water with high flow rate into the vacuum ejector to form negative pressure for sucking condensed water and non-condensable gas in the cold water circulation tank, and the condensed water and non-condensable gas are ejected into the water storage tank through the porous pipe to ensure vacuum environment and condensed water level in the heating tank, the porous pipe is disposed in the water storage tank and submerged in the circulating cold water, the water storage tank is simultaneously used for collecting overflowed condensed water, and the evacuation circulation pump simultaneously sends part of the circulating water into the secondary evaporator for heat exchange, the heat absorption capacity of the heat pump circulating system is increased while the heat of the water storage tank is dissipated.

8. The system of claim 7, wherein a branch of the vacuum ejector is connected to a vacuum pumping pipeline, a water outlet pipe of the vacuum ejector is connected to the perforated pipe, the perforated pipe is closed at the bottom and provided with a plurality of circular jet holes at the periphery, and the perforated pipe is arranged in water in the water storage tank.