1. Evaporator

1.1 What is an evaporator?

Evaporators are a type of equipment used to convert liquids into vapors by heating or reducing pressure. They are usually used to concentrate solutions, separate components, or remove solvents. Evaporators are widely used in various industries including: food and beverage, chemical processing, pharmaceuticals, and environmental engineering.

1.2 Operating principle of evaporator

The working principle of the evaporator is to use energy, heat or pressure to evaporate the water of the solution. The desired product can be clean water or a concentrated solution or compound.

1.3 The role and effects of evaporators

Evaporators play a vital role in industrial processes. By providing efficient and cost-effective solutions for concentration, water recovery and product preservation. This in turn contributes to increased productivity and profitability. Some of the benefits of evaporation systems include:

1.3.1 Concentrating the solution:

Evaporators are commonly used to concentrate a solution by removing the solvent. This then leaves behind a more concentrated solution or a solid product (crystallizer). This is particularly useful in industries such as food, beverage, pharmaceutical, and chemical.

1.3.2 Water Recovery:

Evaporation systems can be used to recover water from various product streams. Such as wastewater or brine solutions. Evaporation allows wastewater to be reused or reduces the amount of wastewater that needs to be treated.

1.3.3 Product Preservation:

In the food and beverage industry. Evaporators are used to remove excess moisture from food products. This extends shelf life by reducing microbial growth and preventing spoilage.

1.3.4 Energy Efficiency:

Many modern evaporator designs incorporate energy-saving features. Such as:

• Heat recovery system (HVE).
• Multiple effect evaporator (MEE).
• Mechanical vapor compression evaporator (MVR).

This helps reduce energy consumption and operating costs.

1.3.5 Environmental Benefits:

By recovering clean water from the waste stream and reducing wastewater discharge, evaporators can help industries reduce their environmental impact. By reducing wastewater discharge and conserving water resources.

1.3.6 Flexibility:

Evaporators are multi-purpose machines. They can handle different product streams under a wide range of operating conditions. Making them suitable for a wide range of industries. Evaporator systems can be customized to meet specific process requirements. Including changes in capacity, temperature, concentration and material compatibility. Ensuring optimal performance and efficiency for each application.

2. Waste water evaporator

Wastewater Evaporators are devices used to remove water from waste and pollutants. They are widely used in the fields of water supply and drainage and environmental engineering. Contribute to the wastewater treatment process to meet discharge standards., reuse or recycle. Other names for wastewater evaporators are: Wastewater vaporizer; liquid waste concentrator; Wastewater evaporation system; Waste concentration system, etc.

2.1 Principle of operation of wastewater evaporator

The principle of operation of wastewater evaporator is the process of supplying heat to liquid waste to increase the temperature and evaporate that liquid. This process causes volatile components such as water to escape as vapor, leaving a more concentrated solution or residue. The vapor is then condensed back into water through cooling. Allowing the recovery of clean water or valuable substances and the removal of unwanted components.

2.2 Some applications of evaporators in wastewater treatment

Evaporators play an important role in various industrial processes. By allowing the concentration of solutions, separation of components and recovery of valuable materials. The task of the wastewater evaporation system is to treat difficult-to-treat wastewater groups. Because the evaporation system will bring higher treatment efficiency and economy when treating more concentrated wastewater. Some applications of the device in wastewater treatment include:

2.2.1 Treatment of wastewater from electroplating, electronic component manufacturing, metal freezing, etc.

Wastewater from electroplating, electronic component manufacturing, metal processing processes contains chemical compounds such as heavy metals, reactants, solvents that are difficult to precipitate and toxic substances such as cyanide, ammonia, etc. Therefore, the treatment of this group of wastewater is often assigned by factories to specialized treatment units. This causes a significant cost to factories. For each type of electroplating process for electronic component manufacturing, metal processing, the specific composition of wastewater may be different. Effective assessment and treatment of wastewater is very important. Some methods of electroplating wastewater treatment include: membrane filtration, flocculation, ionization. Combining an evaporator will be a thorough water treatment solution, bringing many benefits to factories.

2.2.2 Food industry wastewater.

Wastewater from the food industry can contain a wide range of substances, depending on the scale and type of production in the industry. Food wastewater may contain:

• Organic substances: sugar, grease, protein, ….
• Chemical substances: detergents, treatment agents, preservatives, and additives.
• Toxic substances: anti-mold, coolants, ….
• Microbiological substances: bacteria, viruses and microorganisms, ….
• Pollutants from raw materials: such as pesticides from agricultural processes.
• Organic waste: agricultural products, fruits, or meat and fish.

With the above components, food wastewater will be easily treated by methods such as:

• Dissolved Air Flocculation (DAF)
• Physical and chemical, microbiological
• Membrane filtration, ….

Therefore, the evaporator is completely unnecessary to participate in the food wastewater treatment process. It will not bring high efficiency in investment and operation. On the contrary, when the factory needs to save on input water. Or the purpose is to reuse part of the food wastewater or recycle wastewater into the production process. It is necessary to consider the participation of the wastewater evaporation system in the wastewater treatment process.

2.2.3 Treatment of paint, dyeing, printing ink, and tanning wastewater.

Paint, dyeing, printing ink, and tanning wastewater contains components such as: organic substances, chemicals, additives, toxic substances, solids, paint decomposition substances, printing ink and solvents, textile dyes (azo, aniline, phenolic, …). This group of wastewater can be treated by physical and chemical methods combined with membrane filtration. TVTS has carried out a number of similar projects in this field with membrane technology solutions, the clean water recovery rate can be up to 80%. The participation of the evaporation system in the treatment process of this group of wastewater is to move towards the reuse of wastewater. Especially in the textile dyeing industry, some regulations and policies are requiring that no liquid is discharged. Evaporators or crystallizers are very effective solutions for zero liquid discharge (ZLD).

2.2.4 Boiler wastewater, chiller.

Wastewater from boilers and chillers often contains components from the water purification process, the quality of the water supply and additives. Their main components include: Organic substances, salts, metals, possibly toxic substances and solids from waste materials and agglomerates from the water treatment process. In particular, wastewater contains a concentrated salt content. Removing salt will be difficult and expensive when using conventional water treatment technology instead of using evaporators.

2.2.5 Wastewater treatment for small to very small capacity water treatment systems.

Some factories discharge a small amount of wastewater. Building a wastewater treatment system including many tanks and equipment is expensive and sometimes not suitable for the permitted area of ​​the factory. Choosing a wastewater evaporator helps treat wastewater to achieve high water quality. At the same time, it does not require a cumbersome, complicated treatment system.

2.2.6 Treatment of hazardous wastewater, landfill wastewater, waste water treatment plants and waste water power plants; Treatment of concentrated stream after RO system. Effective solution for wastewater treatment Zero liquid discharge.

3. Types of wastewater evaporators commonly used today

Evaporators are widely used in wastewater treatment, concentrating wastewater, so as not to create waste streams. The final products are clean water and concentrated solutions or solids. Some common types of evaporation equipment/systems today:

3.1 Falling film evaporators

Liquid flows down the vertical surface as a thin film while being heated. Promotes efficient evaporation.

3.1.1 Advantages:

Falling film evaporators typically have high heat transfer coefficients due to the thin film of liquid flowing down the heated surface. This allows for efficient evaporation with a relatively low temperature gradient. Operates under vacuum conditions, causing the liquid to boil at a low temperature. This results in less energy input than other evaporators. As the liquid film flows downwards by gravity, it spends very little time in the evaporator, reducing the risk of degradation or thermal damage to heat-sensitive products. Suitable for heat-sensitive products due to short residence times and low operating temperatures. Continuous operation allows for stable, uninterrupted production.

3.1.2 Disadvantages:

Falling film evaporators are most efficient with low viscosity liquids. High viscosity liquids may not form a uniform thin film. This results in uneven evaporation and potential for clogging. If the evaporating liquid contains solids or has a tendency to form scale or sludge. Scale can form on the heat transfer surfaces, reducing efficiency and requiring frequent cleaning. Falling film evaporators are relatively complex in design with complex internal components. This can make maintenance and cleaning more difficult than simpler types of evaporators.

3.2 Forced circulation evaporators

The liquid is circulated through the evaporator by a pump to enhance heat transfer and prevent clogging.

3.2.1 Advantages of the device

Since they continuously circulate the solution through the heat exchanger, allowing for efficient solvent removal. These evaporators maintain high heat transfer rates due to the forced circulation of the solution through the heat exchanger. Forced circulation evaporators can handle a wide range of feed flow rates and concentrations. This makes them suitable for applications in various industries. The continuous circulation of the solution helps to minimize clogging on the heat transfer surface. Since any precipitates or solids present in the solution will be continuously carried away, reducing the possibility of agglomeration. In crystallization processes, forced circulation evaporators can better control the crystal size and morphology. By adjusting process parameters such as temperature, flow rate and residence time.

3.2.2 Disadvantages of the equipment

Forced circulation evaporators typically require high energy consumption. Due to the need for pumps to circulate the solution in the system. Installation and setup of forced circulation evaporators are complex and expensive. Due to the requirements for pumps, piping and control systems. Although the tendency to scale is reduced, forced circulation evaporators are still susceptible to scale. If the solution to be evaporated contains precipitates at high concentrations or temperatures. Changes in flow rate, temperature or concentration can affect the performance of forced circulation evaporators.

3.3 Plate evaporators

The liquid flows between parallel plates while being heated, allowing for high heat transfer rates. Plate evaporators, also known as plate heat exchanger evaporators, have advantages and disadvantages, such as:

3.3.1 Advantages of the device

Plate evaporators use a large surface area for heat transfer. This results in efficient evaporation and concentration of the liquid. Plate evaporators are compact and space-saving compared to other types of evaporators. This makes them suitable for applications where space is limited or a smaller footprint is desired. Plate evaporators can handle a wide range of flow rates and temperatures. This makes them suitable for a variety of industrial applications. Plate evaporators can be started up and shut down quickly. This allows for flexibility in production planning and minimizes downtime. The smooth surface of the plates in the device reduces fouling because there is less area for fouling to accumulate. This helps maintain high heat transfer efficiency over extended periods of operation.

3.3.2 Disadvantages of the Equipment

Although plate evaporators are well suited for small to medium scale applications, they may not be suitable for large scale production due to limitations in plate size and the complexity of scaling up the system. Plate evaporators consist of multiple plates with gaskets or seals between them. They can be prone to leakage if not properly maintained. The initial investment for plate evaporators can be higher than some other types of evaporators. Due to the quality of the materials used to make the plates and associated equipment. Plate evaporators may have limitations in the maximum temperature and pressure they can handle. This may limit their suitability for some high temperature or high pressure applications.

3.4 Flash evaporators

The liquid is suddenly exposed to a lower pressure environment, causing rapid evaporation.

3.4.1 Advantages of the device

Flash evaporators typically require less energy than other evaporation methods. They utilize the latent heat of vaporization of the liquid to evaporate. This can be more energy efficient than heating the entire solution. Flash evaporators can rapidly evaporate large amounts of liquid. This makes them suitable for processes that require rapid evaporation rates. Flash evaporators can be designed to handle a wide range of flow rates and capacities. They are easy to apply to different industries. “Flash evaporators” allow heat recovery from the evaporated vapor, which can be used for other processes in the system. This helps increase overall energy efficiency. Flash evaporators have fewer moving parts than other evaporation systems. This reduces system downtime for maintenance.

3.4.2 Disadvantages of the device

Problems with residue and corrosion. Flash evaporators are not suitable for all types of liquids or solutions. Substances that are susceptible to decomposition or undergo undesirable reactions during flash evaporation. Although in the long run, “Flash” evaporators can be more energy efficient than other devices. But the initial investment cost of “Flash” is quite high. The design and operation of flash evaporators can be relatively complicated. Therefore, it requires highly skilled personnel in installation, operation, maintenance and servicing.

3.5 Rotary evaporators

Rotary evaporators are used in laboratory settings. Involve rotating samples under vacuum to facilitate evaporation at lower temperatures.

3.5.1 Advantages of the device

Efficient solvent removal due to heat transfer mechanism and large surface area. Ability to precisely control temperature and pressure conditions during evaporation. Allows fine-tuning of the process to suit specific requirements. Rotary evaporators can handle a wide range of solvents and sample types. Making them versatile tools for a variety of applications in the chemical, pharmaceutical and other industries. Solvent recovery for high purity. Automation features such as programming and remote control. Enhances convenience in the laboratory.

3.5.2 Disadvantages of the device

Rotary evaporators can be expensive to purchase and install. Especially models with advanced features or automation capabilities. For the laboratory, requires approximately 1 workbench of installation space. Especially larger models or those equipped with additional accessories such as condensers and vacuum pumps. Requires experienced users due to complex operations. Improper handling or installation of rotary evaporators can result in sample loss. Or sample contamination, especially if volatile compounds are involved. The equipment requires regular maintenance to ensure optimal performance and safety.

4. Names of some wastewater evaporators of interest

• Forced Circulation Evaporators: Force Circulation MEE Evaporators; Force Circulation MVR Evaporators.
• Flash Evaporators: Flash MEE Evaporators; Flash MVR Evaporators.
• Negative Pressure Heat Pump Vacuum Evaporators: Heat PumpVacuum Evaporators.

5. Reputable supplier of wastewater evaporation equipment

Currently, wastewater evaporation equipment/systems are not directly manufactured in Vietnam. Products are often imported from countries such as Germany, Italy, USA, Japan, Korea, China, India, etc. We are confident to be the leading unit in Vietnam in researching and applying evaporation equipment to wastewater treatment. TVTS has implemented many projects on wastewater evaporation equipment in Vietnam. We have enough knowledge and experience to provide suitable wastewater treatment solutions for your factory. TVTS always has modular wastewater evaporation equipment available for direct testing at the customer’s factory. Testing at the factory allows to evaluate the properties of each type of wastewater at the factory. Use the basis to adjust the design, develop a reasonable construction plan. Thereby optimizing the treatment efficiency of the system and bringing the highest investment efficiency to customers.

We provide complete wastewater concentration and evaporation solutions. Include:

• Consulting on wastewater treatment technology and solutions.
• Designing wastewater treatment systems.
• Providing wastewater treatment equipment.
• Construction, installation, operation.
• Training. Technology transfer.
• And after-sales services: maintenance and repair.

The solutions and technologies we offer always optimize benefits for customers. High wastewater treatment efficiency, saving investment and operating costs, automatic and safe condition system, remote monitoring and operation of the system.

If you really need a consulting unit and provide evaporation equipment for your factory. We are always ready and eager to accompany you. So that customers can choose the wastewater evaporation technology suitable for their factory. Meet green standards and certificates, improve the quality of wastewater discharge of the factory. Up to standard wastewater reuse or water circulation. Thanks!