We are A.P.Engineers, design, engineering & consultancy, involved in water and waste water treatment industries with more than eighteen years of experience. We manufactured, supplied many zero discharge systems including Effluent treatment Plant, Reverse Osmosis Plant, Multiple Effect Evaporator to various industries and all over India.

Our design and engineering team manufactured many multiple effect evaporators with excellence performance and proven design that suitable for customer with trouble free operations. We installed many multiple effect evaporator from 30KLD to 280KLD capacity of various Evaporator with salt recovery systems and achieve zero discharge in plant. With wide knowledge and practical experience in this field enable us to design and produce multiple effect evaporator with latest technology.

Our main products in evaporator are

Falling Film Evaporator

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.

A part of evaporated vapour is recycled to first calendria 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. By using Thermo Vapour compressor and multiple stages, steam economy up to 1:6 is achieved. This result depends on feed water quality.

In last vapour separator, evaporated vapour is condensed by direct contact condenser or indirect contact condenser. In direct contact condenser, cooling water from cooling tower is sprayed in top and absorbs, condense vapour in to water. This will heat cooling water and returned to cooling tower to reduce temperature. In indirect contact condenser, vapour is condensed by cooling tower water by heat exchanger (shell & tube / Plate type). Non condensable gas from system is removed by water ring vacuum pump.

We installed many falling film evaporator capacity up to 280KLD for various industries. Mainly falling film evaporator are suitable for handling reverse osmosis reject water and having more than 40,000mg/l TDS. This system evaporates up to 90% of feed and gives concentrate 300gram per litre. This concentrate is dried in drier / crystallized in crystallizer / or handled with forced circulation with pusher centrifuge.

Forced Circulation Evaporator

In falling film evaporator, 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 calendria and heating only happened in calendria. 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.

Falling film with forced circulation

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 falling film and forced circulation system. 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 calendria. In our design, there is no need for additional steam for forced circulation. With also power saving is achieved by combination system.

Waste Heat Recovery Evaporator

In industries, heat is recovered from many processing units such as hot air drier, oven, cooker etc., by 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.

Crystallizer

For textile industries, sodium sulphate salts are used for dyeing process. This salt is concentrated by evaporator up to 1.20 sp.gravity (nearly 22% salt content) and separated by adiabatic crystallizer. This crystallizer reduce temperature by adiabatic evaporation and reduce its solubility less then 5gram per litre from 22gram per litre. Insoluble salts are crystallized as Na2SO4.10H2O. this salts are separated in nutch filter and reused to process.

For sodium chloride and other salts, salts are separated from slurry solutions by gravity in conical clarifier and further separated by pusher centrifuge / centrifuge. We supplied crystallizing unit for various type of salts and products.

Vertical Thin Film Dryer

For Evaporator concentrate water, dryer are used to separate salts by evaporation. Concentrate is sent to dryer and evaporated completely. Un evaporated solids such as salts and impurities are collected at bottom. This system reduces need for solar pond. Our dryer is unique in design and operate continuously. It's in build scrapper mechanism removes salts, deposited on inner surface of dryer and removed by conveyer. Our special screw mechanism and unique rotary valve enables system run under vacuum. This system used to most of salts separation without need of pusher centrifuge / centrifuge and recycling of water. Further it gives ready to pack salts and handle high scaling liquids.

Consultancy & Service

A.P.Engineers also provides consultancy and service for evaporator and its related applications. We modified, improve design on existing system of client and increase its efficiency. With also, we provides our service on tube changing, evaporator revamping, pipe and ducting line work of evaporator.

Our Services Includes

own fabrication unit with latest equipments for precious quality in manufacturing. Our design and engineering team gives standards that match to international quality. We installed and run plant suitable for textile industries, pharmaceuticals industries, chemicals industries, food processing units etc.