Low-temperature evaporator is an important part of the full range of industrial wastewater treatment technology products.
The V-HP series vacuum heat pump evaporation system uniquely adopts compression heat pump technology, combined with a suitable vacuum operation range, so that it has a wide range of adaptability for the evaporation and concentration treatment of various industrial wastewaters, and greatly reduces the treatment energy consumption, which not only makes the concentration and reduction of various wastewaters more technically reasonable, but more importantly, it makes the application users economically willing to accept it.
The V-HP series vacuum heat pump evaporation system has an energy efficiency ratio of more than 9 under standard working conditions, far exceeding the multi-effect evaporator (the energy efficiency ratios of one effect, two effects, three effects, and four effects are 0.9, 1.7, 2.4, and 3.0 respectively) and the expansion concentration evaporator (the energy efficiency ratio is 4.2). More importantly, due to its different technical organization from the past, its full-process operating temperature is lower than 45°C, so it is very suitable for industrial wastewater applications accompanied by the recovery of heat-sensitive substances. At the same time, because the optimized heat pump system in the system structure has a sufficiently wide adaptability to working conditions, it has the ability to adapt to the threshold of the boiling point increase in the evaporation and concentration process often encountered in wastewater liquid, and can still maintain its very high energy efficiency ratio. (For example, for a 25% NaOH solution, the host energy efficiency ratio can still reach 6.5)
The main application industries of the V-HP series vacuum heat pump evaporation system:
★Electrochemical industry:
Purification and recovery of wastewater
Purification and recovery of eluate from ion exchange devices
Purification and recovery of eluate from membrane devices
Purification and recovery of precious metals, nickel and chromium plating solutions
★Petrochemical:
Concentration of emulsified oils and fats
Solvent recovery
Ethylene glycol recovery
Separation of organic compounds in water
★Food industry:
Purification and recovery of wastewater
Collection of vegetable oils
Collection of whey and protein
★Steel industry:
Purification and recovery of wastewater
★Chemical-pharmaceutical:
Purification and recovery of wastewater
Purification and recovery of solvents
★Textile printing and dyeing:
Reduction of mercerized wastewater and recovery of dilute alkali
Advantages of the V-HP series vacuum heat pump evaporation system:
The V-HP system can make the goal of “zero emission” more feasible
V-HP series vacuum heat pump evaporation system:
★The V-HP system uses scroll compressors and screw compressors as well as environmentally friendly 410A refrigerants, and adopts strict processes to ensure the tightness of the refrigerant in high-pressure operation.
★The V-HP system is creatively combined with the wastewater circulation liquid distribution system. Through the magnetic closed pump, it consumes very little electricity, greatly improves the heat transfer efficiency of the heating coil, and completely avoids the adverse factors of the boiling point increase caused by the liquid column pressure, which improves the energy efficiency of the whole system as a whole.
★The V-HP exhaust method solves the impact of non-condensable gases on the efficiency of the cooling coil, and at the same time minimizes the impact of the extraction of uncondensed water vapor on the heat load of the vacuum pump, so that the system’s auxiliary maintenance system needs to be minimized, greatly reducing energy demand and dependence, and reducing the capacity and use time of the vacuum pump.
★The V-HP system integrates and optimizes the system logic operation control, greatly simplifies the working requirements of the system and components, and makes it possible to omit the inlet pump, outlet pump, vacuum detection and other devices in some occasions.
★The evaporation and concentration ratio of the V-HP system can be adjusted according to user needs. For wastewater without boiling point increase and material crystallization, in principle, the discharge of residual liquid can be reduced as much as possible through multiple cycles.
The V-HP vacuum heat pump evaporation system includes five main subsystems: refrigeration heat pump compressor system, sewage evaporation condensation concentration system, vacuum maintenance system, intermediate circulation cooling system and automatic control operation system.
★The joint working process of the refrigeration heat pump compressor system and the sewage evaporation condensation concentration system.
For sewage concentration, a heating source must be required to heat and vaporize it, so that the water in the sewage can be separated from the sewage, and then a lower temperature cold source is required to condense the vaporized water vapor into condensed water without pollution sources, or qualified discharge, or qualified reuse.
The composition of the cold and heat sources in this system obtains high pressure and high temperature through the compressor. The working fluid gas passes through the condenser, and the working fluid is cooled into liquid. At the same time, the heat is transferred to the sewage, which vaporizes the sewage. The condensed working fluid liquid is decompressed by the electronic expansion valve and absorbs the heat of the water vapor generated by the sewage vaporization in the evaporator. The working fluid (410A) becomes a low-pressure gas, becomes the suction gas of the compressor and is compressed again, and the cycle works in this way.
The water vapor generated by the sewage releases heat while the working fluid (410A) absorbs heat, condenses into clean condensed water in the evaporator, and is discharged through the water collection tank and water collection tank.
As the process continues, the water in the sewage is continuously vaporized and condensed and discharged, and the concentration of the sewage continues to increase. Until the target concentration is reached, it is discharged by the concentrated solution pump. For different types of sewage, the remaining high-concentration sewage discharged is further crystallized and separated, and directly heated, dried, incinerated and other deep treatments are carried out.
★Automatic control system (omitted)
★Vacuum maintenance system:
The V-HP vacuum heat pump evaporation system is specially designed to operate in a vacuum environment. On the one hand, it makes the water vaporization at 100℃ or above (depending on the sewage concentration and the dirt content) under normal pressure to be controlled to operate in the range of about 40-50℃, which not only reduces the thermal loss of the system and improves the efficiency, but also greatly improves the efficiency of water vapor generation and condensation precipitation in the vacuum environment, that is, it greatly improves the heat transfer efficiency, significantly reduces the demand for equipment heat transfer surface, reduces equipment cost and volume, and at the same time, the low working temperature prevents many reusable dyes, essential oils, and proteins in concentrated sewage from denaturation at high temperature.
The vacuum maintenance system of this system adopts a two-stage water ring vacuum pump to maintain the system at about -95～-97Kpa. During the operation of the system, with inevitable leakage, as well as air and other non-condensable gases brought in during the addition of sewage to be treated, the system vacuum will be continuously destroyed, affecting the system efficiency. Therefore, the system is designed to automatically detect and identify, and start the vacuum pump, usually working for 1 to 2 minutes every half hour.
★Intermediate circulation cooling system:
The V-HP vacuum heat pump evaporation system innovatively adds an intermediate circulation cooling system to automatically adjust the system to work stably in different seasons. Through a simple system structure, it effectively eliminates the system entropy increase heat while obtaining the output of evaporated condensed water.
Theoretically, there is always a situation in which the input work entropy increase becomes heat in the refrigeration heat pump unit. In order to maintain the balance of the system, this part of the heat must be removed.
The V-HP system has found a good working point in the process design of how to remove the unbalanced heat of the system, and has determined to improve the energy efficiency ratio compared with similar international and domestic systems.
Compressor operating parameters under different working conditions:
Selection parameters:
V-HP selection parameters
Model
Evaporation capacity (L/h)
Evaporation capacity (l/h)
Installed power (KW)
Operating power (KW)
Shape (l×b×h) V-HP120 110 9.35 7.4 2300×1200×3300 V-HP240 230 16.95 14.9 2300×1200×3330 V-HP380 355 25.9 22 3000×1500×3330 V-HP485 480 dimension 3 4.2 31.5 3000×1800×3500 * The larger model is a modular unit, and multiple units are stacked on the above four models.
The V-HP series system vacuum heat pump evaporation system has the following major energy-saving principles:
In addition to the system heat dissipation, cooling loss and thermodynamic entropy increase loss during operation, the heat used to evaporate the wastewater and the heat discharged by the evaporated water vapor being condensed are continuously recycled through the heat pump system. The higher the utilization rate and the more repetitions, the higher the energy efficiency ratio.
Second, the system operates as close to the ambient conditions as possible, the lower its comprehensive heat dissipation and cooling loss, the smaller its irreversible loss, and in a broad sense, the lower its damage to physical properties, so a vacuum heat pump system is used.
Third, for the operation control of the hot and cold ends of the system, minimizing the energy level difference as much as possible is the pursuit point for reducing the increase of internal thermodynamic entropy. It is a long way to go to improve the energy efficiency of the whole system, and it is necessary to effectively develop products with field adaptability. I am confident that it is not a big problem in theory and industrial technology capabilities. It is just that in the initial stage of such application fields, no relevant companies have recognized this huge application field. This is also the step faced by the vacuum steam direct heat pump we are developing and researching.
★Technical and economic cases:
After the construction of an evaporation and concentration system with a daily processing capacity of 80 tons with a total investment of 8 million yuan (including civil engineering), the concentrated reduction is less than 6 tons of sewage per day handed over to the designated sewage treatment center for environmental protection, and the emission reduction is 90% to 95%. The energy efficiency ratio of the system operation at that time did not exceed 4.0, and the direct cost of daily operation was 20,000 yuan, which not only effectively solved the environmental protection problem but also had considerable economic benefits.
