Wastewater evaporation is a method of removing water content from wastewater by converting water to vapor and retaining polluting waste.In other words, a wastewater evaporator is a device that uses thermodynamic and mass transfer processes to evaporate the water present in the wastewater and concentrate the remaining waste.
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What is a Wastewater Evaporator?
Wastewater evaporator is also known as wastewater evaporator, wastewater evaporator, liquid waste condensing system.
A wastewater evaporator is a device that functions to reduce the mass and volume of waste. Wastewater evaporation is an effective method for the removal of contaminants and liquid waste in difficult wastewaters with high pollutant composition.
For waste in heavy industrial production, which may contain up to 150,000 ppm TDS (total dissolved solids) or more, vaporization is the most efficient and proven wastewater treatment method for collection. water recovery and reuse. In addition, no other technology can achieve high water recovery and concentration rates, capable of achieving total residual solids concentrations above 85%. Wastewater condensation and vaporization can remove salts, heavy metals and toxic, heavy pollutant compounds present in wastewater, greatly reducing wastewater and waste treatment costs.
Working principle of wastewater evaporator
Wastewater evaporator operates on the principle of thermodynamics to transfer heat to the waste solution source in combination with the air circulation process to evaporate the wastewater. Depending on each wastewater evaporation technology and heat source used, the operating principle is also different. But in general, the operating principle of the wastewater evaporation system includes the following processes:
Step 1: Feed liquid into the tank
Waste water is brought into the treatment tank from the storage tank with the flow to be treated and in accordance with the capacity of the vaporizer.
Step 2: Wastewater supply pump
The pump is used to pump wastewater into the wastewater evaporator and can be activated by a toggle switch or using an automatic filling system.
Step 3: Heat supply
Wastewater evaporation depends on the hot steam generated by the heat exchanger, which increases the vaporization and solids concentration. The heat in the evaporator creates a flat or even boiling surface on the surface of the solution.
Step 4: Blow air
The blower on the waste water evaporator draws air into the evaporator bath to remove water vapor and aid in the heating process.
Step 5: Compress
Air compressors are used to assist the vaporization process and can be positive, centrifugal or axial displacement. Wastewater evaporators using compressors need to have an external steam source such as a boiler or heater in the feed tank.
Step 6: Remove steam
The nebulizer or eliminator removes contaminants from the process which may be in the form of oils or other substances. They are made from corrosion-resistant materials and can be designed to be self-cleaning.
Benefits of waste water evaporator
By reducing the volume and volume of wastewater, wastewater evaporators bring great benefits to wastewater treatment systems, especially factories that need to reuse wastewater. With an integrated design into a compact and complete system, the wastewater concentrator is easy to install and operate, taking up little space and installation space. In addition, using a wastewater evaporator also brings some of the following benefits and advantages:
Energy saving: Wastewater evaporation systems operate on a 1:1 ratio where the amount of energy used to concentrate the wastewater is equivalent to the amount of water being evaporated. This ratio can be improved by using multiple processes, such as taking steam from one operation and using it for another process.
Zero Liquid Discharge: In many industrial plants, wastewater evaporators can be installed to achieve Zero Liquid Discharge standards. Like water reuse systems, wastewater evaporation is an important equipment for systems implementing the ZLD process, reducing sources of wastewater and waste into the environment, achieving green environmental certifications. school.
Total Dissolved Solids (TDS): Wastewater treated by an evaporator can produce less than 10 mg/L or as little as 2 mg/L. These levels allow the treated water to be recycled. used and recycled into the production process.
Cost Savings: When compared to chemical precipitation systems, wastewater vaporizers are much more efficient and cost-effective. While the chemical treatment can operate at 395 liters per minute, the wastewater evaporator can process 190 liters per minute.
Flexibility: Each industry and wastewater treatment system has different concerns and issues. Wastewater evaporators are adaptable to any condition, any industry, and can be programmed to handle any form of contaminant. Wastewater evaporation systems have the ability to operate independently or be added to an existing system to improve the overall wastewater treatment process.
Reduced waste volume: The most significant benefit of a wastewater vaporization system is the ability to reduce waste volume by removing water content. One of the problems that waste management activities are facing is the lack of available space and space for waste treatment. The removal of water from the waste significantly reduces its mass and volume.
Application of wastewater evaporator
Wastewater evaporators have been used successfully in many industrial wastewater treatment applications, e.g., power and chemical plant wastewater, metal finishing waste, spent pulp alcohol, emulsified oil stream, highly soluble BOD (sugar) stream and non-volatile organic or inorganic water stream containing dyes, acids and bases. One of the main applications for wastewater evaporators is to remove oil-contaminated waste from wastewater in some petrochemical plants, and to remove non-volatile inorganic streams containing dyes in dyeing chemical factories.
Plating, metal processing, electronic components
The metal finishing industry today uses “electroless” plating processes, for example in the manufacture of printed circuit boards. This creates a difficult-to-treat waste stream containing chelating agents such as organic acids (e.g. EDTA) or ammonia, which prevent the normal precipitation of heavy metal hydroxides. To avoid the cost of chemical treatment or wastewater filtration, some factories pay for collection and treatment, a very expensive solution. Although wastewater evaporators cannot completely solve the problem, they significantly reduce treatment costs.
There are several applications for wastewater evaporators in the food industry. Although wastewater from food production is non-toxic and biodegradable, it contains biochemical oxygen demand and solids from many processed foods. Washing vegetables and slaughtering animals produce dissolved organic materials that need to be removed from the water before it can be reused or released into the environment.
The pharmaceutical industry requires clean water because factories need purified water in the production process. Regulatory agencies set standards for the purity of the water used when making drugs. Pollutants arising from the pharmaceutical manufacturing process are toxic and dangerous, so using wastewater evaporators becomes necessary.
Paint and ink production
Water is a necessary part of the paint manufacturing process for water-based paints and cools oil-based paint factories. Wastewater from paint production contains large amounts of alkali from cleaning and from cooling towers. Wastewater from paint production has a small volume but concentrates many pollutants.
Machining coolant is used to cool tools and fabricated parts that overheat during machining. Coolants are water-soluble oils, water- and oil-soluble synthetics. During normal operation, coolant is continuously passed through the machine until it is no longer useful and needs to be cleaned. It is then fed into the evaporator to evaporate the water, leaving behind the metal and oil in the evaporation tank.
Landfill, waste treatment plant
Landfills have dissolved organic and inorganic matter, heavy metals and other organic compounds. Wastewater from landfills can have a serious negative impact on the environment and should be treated. Wastewater evaporators are perfect for this application as they are adaptable to variations in the wastewater stream.
During battery manufacturing, a significant wastewater stream containing sodium sulfate is released. This can be purified using an evaporator, allowing it to be reused.
Classification of wastewater evaporators
Wastewater evaporators are classified according to heating source, circulation method and heat exchanger. The heating energy source can be provided by hot water, steam, thermal fluids, exhaust gases and electrical energy – directly through resistance, or indirectly by heat pumps or mechanical vapor recompression. Circulation methods include natural circulation, forced circulation and thin film. Direct heat exchange techniques include immersion heaters, submersible combustion or submersible steam. Indirect heat exchange techniques include internal or external shell and tube heat exchangers, and plate heat exchangers.
Many heating methods exist to recover condensation energy and water for reuse in the process cycle, reducing total energy consumption for water evaporation by up to 25 times, including heat pump vacuum evaporation. , single or multiple effect distillation (MED) or mechanical compression evaporation (MVR) technology.
Forced Air Evaporator
The forced evaporator consists of a feed pump, an evaporator tank with heater, a circulation pump, a blower, a mixing tube, a de-mist device and an air outlet. Wastewater is pumped into the evaporation tank and heated. The air and wastewater are mixed and transferred to the evaporator tank, where it passes through the de-fog unit and out of the air outlet.
Heat Exchanger Evaporator
In a heat exchanger, high-temperature oil, which has been heated in an oil-filled coil, is pumped into a coil inside a contaminated waste tank.
Leachate wastewater evaporator
The Leachate wastewater evaporator is designed to reduce leachate volume. They remove leachate and remove purged vapor, while leaving behind sludge and solids.
Thermal Fluid Oxidation Wastewater Evaporator
The thermoliquid oxidation method involves spraying liquid waste, under pressure, near a flame. At 1250°F, all volatile organic compounds (VOCs) are oxidized and dissolved, while solids are oxidized to ash. The contaminants are changed into inorganic ash.
The vacuum waste water evaporator reduces the pressure in the evaporator tank below atmospheric pressure, lowering the boiling point of the wastewater. This process eliminates the need for heat and can be used with liquids with high boiling points.
Heat pump vacuum evaporators offer reduced electrical energy consumption and outstanding reliability for low to medium flow produced water treatment applications (10-50 m3/day). Evaporation occurs under high vacuum, 4 kPa absolute pressure, which reduces the boiling point of water to a temperature of about 30 degrees Celsius. Energy consumption is reduced to about 0.15 kWh/L distillation. (5 times less than atmospheric evaporation) because most of the energy in the form of latent heat is reused to produce new vapor.
MVR wastewater evaporation system
MVR is Mechanical Vapor Recompression). Wastewater evaporator MVR is a forced circulation flash evaporator using mechanical vapor compression. MVR is now recognized as one of the most energy efficient and energy efficient waste water vaporization technologies. It uses electrical energy to recover the energy of the secondary steam generated by itself, thus reducing the need for external energy.
MVR evaporator works on the principle of converting electrical energy into mechanical energy so that the low quality secondary steam in the MVR evaporator system is compressed by the compressor, the temperature and pressure of the steam is increased , thereby increasing the enthalpy of the secondary steam, which then enters the heat exchanger for condensation, making full use of the steam’s latent heat.
In conventional evaporators, heat separation processes such as evaporation and distillation can be energy intensive. The MVR evaporator allows this energy to be continuously recycled by compressing the steam to a higher pressure and temperature. Compared to a conventional evaporator system, the operating energy consumption of the MVR evaporator system only 1/3~1/4 of MEE evaporator system.
In contrast to a heat pump evaporator system, there is no intermediate thermal fluid required in an MVR system. The structure of the MVR evaporation system includes the following devices: MVR vapor compressor (also known as steam centrifugal compressor), heat exchanger (evaporator), separation device (crystallizer) , evaporative circulation pump, preheater, auxiliary tank and pump, control system.
Advantages of MVR waste water vaporization system
The MVR evaporative system only consumes steam during normal start-up, saving energy and delivering high performance. Compared with the traditional evaporation system, the MVR evaporator can provide a smaller and more stable temperature difference heat transfer, which can achieve a gentler evaporation process. MVR evaporator is suitable for heat-sensitive materials, can improve product concentration quality, and can effectively reduce the risk of scaling caused by high heat transfer temperature difference.
The MVR wastewater vaporization system has short process flow, simple and stable operation, equipped with CIP cleaning pipes, on-site cleaning. MVR technology uses generated steam for heat instead of expensive heat sources. MVR technology does not require a cooling tower, significantly reducing cooling water usage. The MVR system can evaporate at low temperatures (50 °C ~ 100 °C) and does not create foam, significantly reducing damage to equipment materials and increasing system life.
The structure of the MVR vaporization system is simple, fully automatic control, and operates continuously. Compared with traditional evaporator, MVR evaporator temperature difference is much smaller, can achieve moderate evaporation, greatly improve product quality and reduce fouling. No need for condenser or only a small area of condenser, very simple structure and process, fully automatic operation and continuous operation, safe and reliable.
The installation space of the MVR evaporator is about twice that of the traditional multi-effect evaporator; The equipment investment amount of the MVR system is larger, but the operating cost is much lower than that of the traditional multi-effect evaporator.
The company provides and installs wastewater evaporators
Hoa Phat Eco is a pioneering wastewater evaporator supplier in Vietnam. We custom design and install wastewater condensing and evaporation systems specifically for the individual wastewater characteristics of various industrial wastewater treatment systems.
We provide a complete solution for condensing and evaporating wastewater from design, construction and installation to operation and technology transfer services. The wastewater evaporation technologies that we research and apply focus on optimal treatment, saving operating costs, automation and safety for the system, ensuring effective investment for Factories need to install wastewater vaporization systems.
In Vietnam, industrial production processes, especially heavy and high-tech industries, require many complex processes, thereby the need to use toxic compounds and chemicals as well as pollution. High. Some types of wastewater contain complex components and toxic compounds that cannot be treated with conventional treatment technologies. Therefore, Hoa Phat Eco’s wastewater evaporator is a suitable solution to thoroughly solve this problem.
We look forward to accompanying and supporting our customers to choose the most suitable wastewater evaporation technology for their plant, as well as provide solutions for wastewater reuse and emission reduction dangerous, join hands for a sustainable green environment.