A.P. Engineers

Perundurai, Erode, Tamil Nadu

In industries, heat is recovered from many processing units such as hot air drier, oven, cooker etc., by waste heat recovery evaporator. This type of evaporator is flexible and allows running on various load. Depend on heat load, it evaporate feed water. No requirement for steam. This type of evaporator designed carefully, such that it will not disturb heat source such as hot air drier, oven etc by back pressure or resist hot air flow rate. Further hot air flue gas is cooled and sent atmosphere. This type evaporator suitable for concentration, effluent management, protein recovery plant etc. We designed our evaporator with by- pass arrangement for evaporator maintenance. Further evaporation depend on heat load, system designed to withstand maximum heat load in system. We installed many waste heat recovery evaporator 40kld to 200kld capacity for fish meal industries.

Product Description: Owing to our expertise in this domain, we are offering superior quality Multiple Effect Evaporators. The offered protein recovery evaporator is widely used for fish meal industry for high salt water, high organic load waste water evaporation purpose. Designed with waste heat source, such as drier hot air, process waste steam, etc. In Multiple effect evaporator the set industrial norms, our offered range comes in various meet with lpg firing system, steam, hot air, etc. which clients can choose from as per their requirement. We can also customize this range as per the details provided by the clients.

How it Works : Water is boiled in a sequence of vessels, each held at a lower pressure than the last due to which the boiling point of water decreases as pressure decreases. The vapor boiled off in one vessel can be used to heat the next, and only the first vessel (at the highest pressure) requires an external source of heat. MEE available in 30 kld to 200 kld used for various industries

In Forced circulation system, liquid is circulated with high pressure and velocity. For that, we need high energy and heavy recirculation pump. For that, we offer combination of Film Forced Circulation Evaporators. This will help to avoid scaling due to high concentrations. This combination system is more efficient in high salt water where as insolubility increases with higher concentrations. We offer two falling film with one forced circulation system, three falling film with one forced circulation system to achieve desired concentration without scaling in last calandria. In our design, there is no need for additional steam for forced circulation. With also power saving is achieved by combination system.

Falling Film Evaporators, water is boiled in a sequence of vessels, each held at a lower pressure than the last. Because the boiling point of water decreases as pressure decreases, The vapour boiled off in one vessel can be used to heat the next, and only the first vessel (at the highest pressure) requires an external source of heat. This is called multiple effect and no of stages / effects is depend on quantity of vessel / calandria in sequence.Theoretically, one kg of steam evaporates one kg of water. In multiple effect evaporator, one kg of steam evaporates up to 6 kg of water by no of effects and vapour recirculation by thermo vapour recompressor. It is called as steam economy 1:6. Feed is preheated to nearby boiling temperature in Pre heater that connected with all calandria. All calandria are operated at stage by stage vacuum with reduced temperature. So feed is preheated by stage wise from lower temperature to higher. Then it is passed via first calandria tube bundles as fine film layer over the tube surface area. In shell side fresh Steam is given via Thermo Vapour Compressor. Feed is heated and evaporated in calandria. Evaporated Vapour is separated in Vapour Separator, vapour is sent to second calandria Shell side. Un evaporated feed is transferred to second calandria tube side.Here further evaporation is done. So each calandria evaporates feed and concentrate coming out from last calandria. In this system, concentration is achieved by stage by stage and each calandria have higher concentration as stage increases. A part of evaporated vapour is recycled to first calandria via thermo vapour recompressor. In Thermo Vapour Compressor, Fresh Steam with pressure is passed via steam nozzle. Steam produce high velocity and produce a venturi Effect.This will recirculation a part of evaporated vapour.

In Forced Circulation Evaporators water is distributed in tubes like a fine film layer on surface of tubes. Due to less wetting in surface and scaling, fouling materials will form a layer of insoluble scale that reduce its evaporation capacity. During evaporation, scaling materials such as calcium, magnesium & silica salts are forms quick and insoluble layer of scales. This will reduce heat transfer and affect system performance. For that, we recommended forced circulation system.In that design, feed is flow inside of tube with tube filled condition and with high velocity and pressure. Due to velocity and pressure, boiling on tube surface is reduced. Pressure inside of system is maintained to avoid boiling inside of tube by vapour head pressure. Further velocity in forced circulation keeps surface on wiping and cleaning. This will not allow developing scales on surface by force of feed water.Feed vapour is separated in vapour separator. Further, with forced circulation system, we can run system with semi slurry conditions with very high concentrations There is no boiling on calandria and heating only happened in calandria. Boiling happened in vapour separator and concentration without scaling is achieved. Further high concentration water and semi slurry water is processed.This will help to separate salt by crystallizer, pusher centrifuge or dryer. By forced circulation system, we can achieve zero discharge system effectively. We installed many forced circulation system up to 80kld capacity. This system is used to high fouling, scaling water, salt separation by crystallizer and pusher centrifuge.

We are offering multiple effect evaporator, water is boiled in a sequence of vessels, each held at a lower pressure than the last. Because the boiling point of water decreases as pressure decreases, the vapour boiled off in one vessel can be used to heat the next, and only the first vessel (at the highest pressure) requires an external source of heat. This is called multiple effect and no of stages effects is depend on quantity of vessel calendria in sequence. Theoretically, one kg of steam evaporates one kg of water. In multiple effect evaporator, one kg of steam evaporates up to 6kg of water by no of effects and vapour recirculation by thermo vapour recompressor. It is called as steam economy 1:6. Feed is preheated to nearby boiling temperature in pre heater that connected with all calendria. All calendria are operated at stage by stage vacuum with reduced temperature. So feed is preheated by stage wise from lower temperature to higher. Then it is passed via first calendria tube bundles as fine film layer over the tube surface area. In shell side fresh steam is given via thermo vapour compressor. Feed is heated and evaporated in calendria. Evaporated vapour is separated in vapour separator, vapour is sent to second calendria shell side. Un evaporated feed is transferred to second calendria tube side. Here further evaporation is done. So each calendria evaporates feed and concentrate coming out from last calendria. In this system, concentration is achieved by stage by stage and each calendria have higher concentration as stage increases.