How are Evaporators used for effluent treatment?
An evaporator in an effluent treatment plant is a device that converts water from liquid wastewater into vapour, while leaving contaminants behind. The goal of a wastewater evaporator is to reduce the volume of waste products, and to recover wastewater.
Let’s understand the concept and usage of evaporators in effluent treatment.
Overview of Evaporation Technology
Through wastewater flows, evaporation technology may be utilized to retrieve valuable goods, or segregate harmful pollutants. By vaporizing a portion of the solvent, usually water, evaporation concentrates a solution. It yields salty liquor that contains almost all of the dissolved salts, from the initial intake.
To finish the process, natural solar evaporation ponds or commercially available evaporation machinery, can be employed.
· Solar evaporation ponds are often limited by potential odour concerns, land availability, and cost, or meteorological and climatological conditions, and
· Mechanical evaporators are compact, efficient, and dependable.
Usage of Evaporators
It is useful for concentrating or eliminating salts, other hazardous components, and heavy metals from a solution. It might also be used to recover valuable by-products from a solution or to condense municipal effluent, before it is further processed and disposed of. The majority of the technology's applications also produce a high-quality, reusable distillate, which is an important feature in locations, where water protection is a key issue.
Types of evaporators
· Vertical Tube Falling Film
· Horizontal Tube Spray Film
· Forced Circulation
· Hybrid and Combined Systems
How are evaporators used for effluent treatment?
Heat is transferred from condensing steam to a low-temperature fluid, via a metallic heating surface, driving the evaporation process. The absorbed heat causes the solvent (which is usually water) to evaporate. As a result, the concentration of solute rises. The resultant vapour can be discharged into the atmosphere or condensed for re-use.
Mechanical evaporation is an energy-intensive method of liquid concentration. As a result, while selecting the most effective evaporator, numerous energy sources should be examined. In an ideal condition, one kilogram of condensed water will evaporate one kilogram of water from the solution. Such a system has steam economics or effectiveness of 1:1.
How can the working of evaporators be more effective?
Firstly, the economy of an evaporator can be enhanced by using multiple- effects. In a multi-effect approach, the vapour from the first impact is employed as the vapour source for precedence. When the temperature drops in each succeeding step, evaporation continues since the boiling point and pressure drop as well.
Secondly, vapour compression is another well-known method for reducing energy input. In the heat exchanger, the vapour released from the evaporator compartment is compressed, to the necessary pressure/temperature levels.
Thirdly, mechanical compressors are the most commonly employed for vapour compression. There are positive displacement, centrifugal, and axial compressors available. In many circumstances, a mechanical vapour compression evaporator system, will merely require an outside vapour source, to get started. In most cases, a small boiler or resistive heater within the evaporator tank would suffice.
Fourthly,a high-pressure steam jet thermal compressor might be considered as well. The use of a thermal compressor appears to be nearly equivalent, to the installation of a second evaporator.
Lastly,excess heat from other process streams can also be collected to save money on evaporation. Instead of steam, heated process fluids might be pumped through heating tunnels, to recover heat and transfer it to the fluid to be condensed, or heat from hot flue gases could be converted to vapours in a re-boiler, and then utilized in an evaporator.
In effluent treatment plants, evaporators are used to minimize the number of regulated waste residues generated, while also increasing the number of precious metals recovered from those wastes. It is less sensitive to oil traces and does not produce waste that must be handled.
Netsol Water is a renowned manufacturer of all water and wastewater treatment plants. We offer effluent treatment, sewage treatment, and most of all zero liquid discharge treatment, which includes evaporation technology to treat the effluent in a better way.