INDUSTRIAL/DISTILLERY EFFLUENT HANDLING VENTURE

ATHENA has been involved in the business of exporting and supplying a wide range of evaporator & Dryer for Industrial/Distillery effluent concentration & drying. Our company proposed following scheme for effluent treatment:

TYPES OF EVAPORATORS UNDER USE BY INDUSTRY

Multiple effects falling film evaporator to concentrate the distillery effluent up to 30-40 % TS.
Multiple effects forced recirculation evaporator to concentrate the distillery effluent up to 60%.
Multiple effects evaporating plant in combination with falling film and forced recirculation calandria to concentrate the product either up to 30% TS or up to 55% TS.
Scrapped surface evaporator to concentrate upto 80% TS.

Falling Film Evaporator

Concentration of highly –sensitive material require a minimum time of exposure to the heated surface. This can be done in falling film evaporators. The tubes are vertical and the product forms a thin film on the inside of the tubes, which are surrounded by steam. The product is preheated to a temperature slightly above the boiling temp. in the evaporator. From the preheater, the product flows to the upper section of the evaporator.

By means of specially shaped nozzle, product is distributed over a spreader plate. The product is slightly superheated and therefore expands as soon as it leaves the nozzle. Part of the water is vaporized immediately.

The steam formed forces the product outwards against the inside of the tubes and it run down the walls of the tubes as thin film. The water content of the film evaporates rapidly as the product passes through the tubes. A steam separator is fitted under the evaporator and separates the vapor from the concentrated product.

The resident time in the falling film evaporator is very short, as only a small amount of the product is treated at the same time.

There is no hydrostatic increase in temperature in a falling film evaporator which means that the value of the saturated vapor pressure corresponds to the vacuum in the tubes. The vapor reaches its maximum velocity at the bottom of the tubes shortly before the discharge end.

Characteristics of multiple effects Falling Film Evaporator

It can be operated at much lower Δ T (Difference between jacket and boiling temperature).
The low Δ T, is favourable to vapor recompression and consequently, the energy consumption is low.
Short holding time.
Low power consumption.
Can be operated at with or without TVR, with TVR efficiency is improved by 25%.
Can be operated at high steam pressure at 9 bar and low steam pressure at 1.5- 3.5 bar on turbine steam exhaust.
Suitable to concentrate the product up to 30-40% TS.
CIP is required after every 8-10 days of continuous running of plant.
After every 8-10 days of running start up of vacuum and steam is required.

Enquiry

Forced Recirculation Evaporator

The forced circulation evaporator was developed for liquors, which are susceptible to scaling or crystallizing. Higher co-efficient are obtained in forced recirculation evaporator. Here a centrifugal pump forces the liquid product through the tubes at an entering velocity of 2-6 m/s and the heating medium surrounds the tubes carrying the liquid. Pressure drop and hydrostatic head in combination are frequently great enough to prevent the liquid from boiling in the tubes, so that the vapor generated is flashed as the liquid enters the vapor separator. Since the velocity of the flashing mixture is high, impingement deflector/baffles in the separator are important to minimize entrainment. Liquid returns to the pump inlet, where it meets incoming feed; vapor leaves the top of the evaporator body to a condenser. Part of the liquid leaving the separator is continuously withdrawn as concentrate.

Characteristics of multiple effects Forced Recirculation Evaporator

High temperature difference between jacket and boiling temperature is required.
High Δ T is necessary to obtain high concentration, due to increased viscosity of the product.
Long holding time
Suitable to concentrate the product up to 60% TS.
The overall co-efficient is very high, which reduces the size of unit.
CIP is required after 45-60 days of continuous running.
No CIP chemicals are required on daily basis.
Plant capacity shall be selected at lesser level as average plant operation is 22-23 hrs.
Heavy power consumption.

Enquiry

Scrapped surface evaporators

Scrapped surface evaporators are used for higher concentration say 80% TS. Distillery (Raw or spent wash effluent) or other industrial effluent can be dried to 90-92 % solid using combination of multi effect evaporator (combination of falling and forced recirculation) single or double effects scrapped surface evaporator & finally to fluidized bed dryer. The product could be sold as fertilizer, cattle feed, agro fuel.

Working principle of Scrapped Surface evaporator

It consists of a vessel (vertical cylindrical) wherein a steam drum is installed.
Steam is used as heating media and scrapper assembly moves around drum & inner dimple jacketed surface to scrap/ remove the layer of product so that efficient heat transfer takes place without affecting water evaporation.
Vessel is maintained under vacuum. Concentrated mass of 80% TS is transferred to further processing.

Concentrated effluent is mixed with back up material for reconditioning in two screw paddle mixer which is led to Agitated fluid bed for further reconditioning. Once product is reconditioned it is transporting system as well specially designed flex plate is used. Hot air at 160-350ºC can be used as heating media. Final product of required moisture content after cooling in FBD last section can be packed directly.

Application of agitated thin film dryer, spray dryer, rotary dryer in drying many industrial effluent have been established. However any drying or drying combination should be studied thoroughly for its commercial viability.

Enquiry

Multiple effects evaporating plant in combination with Falling Film and Forced Recirculation type calandrias

Due to lower concentration level achieved in falling film evaporator and heavy power consumption in forced recirculation evaporator, ATHENA has designed an evaporator using combination of both types of calandria. By opting these combinations we can achieve concentration level of product up to 55% with less power consumption compared to forced recirculation evaporator.

Characteristics of multiple effects evaporating plant in combination with Falling Film and Forced Recirculation type calandrias

It is suitable to concentrate the product up to 30 % as well as up to 55 % total solids.
This combination is good in economical and efficiency point of view.
CIP is required after 8-10 days.
Low power consumption compared to multiple effects forced recirculation evaporator.
Fouling problems start at 45 % TS, so it can be overcome by forced recirculation evaporator at last stage.
Remedial Measure to avoid sudden stoppage or stoppage due to scale formation
Use stand by calandria with valves manifold. With this arrangement plant can be operated continuously for6-8 months or so.
Pretreatment of effluent i.e clarification to remove inorganic salts, sludge etc.
Ato temp. & Pressure, flow control through programmed Logistics control.
Extended wetting rate or higher tube velocity

Enquiry

INDUSTRIAL/DISTILLERY EFFLUENT HANDLING VENTURE

Falling Film Evaporator

Forced Recirculation Evaporator

Scrapped surface evaporators

Multiple effects evaporating plant in combination with Falling Film and Forced Recirculation type calandrias

Looking for "Zero Effluent Discharge Plant"?

Various Projects

Specialised in

Reach us