Evaporators

FBE provides evaporating systems using the most advanced and reliable resources in the industry. FBE evaporation technology is dedicated to meet a wide range of industrial application needs. This gives us a unique data base for today’s applications.

FBE concentration plants are used in the food, dairy, chemical, fermentation and pharmaceutical industries. They are also used for waste water treatments like Spent Wash concentration in Alcohol industries. We manufacture tubular type evaporators with energy saving options such as thermal vapor recompression (TVR) and Mechanical Vapor Recompression (MVR).

We have delivered systems for Milk, Fruit juices pulp concentrates, Herbal extracts, Malt mix slurry, Starch and derivatives, Spent wash concentration, and Aroma recovery for many different kinds of products.

The purpose of concentration is

• For subsequent dehydration
• To reduce the bulk of materials to be preserved
• To prepare other food products.

The rate of evaporation depends upon

• The temp. of surrounding.
• The pressure above the liquid.
• The pressure above the liquid.
• The rate of heat transfer to product.

Energy Efficiency of a FBE Evaporator is a key consideration in the design and operation for each customer’s particular application.

The energy input must also be available at a higher temperature (pressure) than the boiling product. The heating media, almost exclusively, consists of condensing water vapor.

MVR is used to raise the pressure and temperature of vapor. The vapor is drawn out of the evaporator and compressed before being returned to the evaporator and compressed before being returned to the evaporator when mechanical compression is used. The pressure increase takes place by means of mechanical energy, used to drive the compressor. No thermal energy is supplied to the evaporator (except steam for heating in the 1st effect). There is no excess steam which has to be condensed. Apart from the steam used for start up, a MVR evaporator requires no steam and no cooling water. However, if high concentration to be achieved, it is advantageous to use a steam heated finisher for the last concentration. In this way, it will be easier to control the evaporator. An MVR evaporator may also be coupled with TVR and/or multiple effect evaporation stages.

The high initial capital cost of an MVR unit must be weighed against the operating cost savings.

The multiple effect configurations combine two or more evaporator bodies to conserve steam, which is condensed in the first-effect heat exchanger only. Water evaporated in the first-effect vapor body is condensed in the second effect heat exchanger, which provides energy for evaporation in the second-effect vapor body (and so on for additional effects). Vapor from the last effect flows to a condenser. The last-effect vapor body is maintained at a high vacuum with a steam-jet air ejector or mechanical vacuum pump.

A rough “rule of thumb” for comparison purposes is that 1/N kg of steam is required for 1 kg of Water evaporation, where N is number of effects. e.g In 4 effects evaporator 0.25 Kg (1/4) steam is required for 1 kg of water evaporation.

High steam economy is obtained by recompression of the vapor generated from the boiling product. This is done by adding energy to the vapor by a steam jet. Part of vapor separated to be used together with boiler steam, to the thermo compressor. Boiler steam (usually at a pressure of 3.5-10 bar) is introduced through a nozzle creating a steam jet in the mixing chamber whereby vapor from the evaporator is sucked into the mixing chamber. The thermo compressor uses the high pressure steam to increase the kinetic energy and the steam ejects at high speed through the nozzle. The velocity of the mixture of boiler steam and vapor is reduced in diffuser and consequently, the pressure and temperature are increased, making the mixture suitable as a heating medium in the calandria.