Evaporation Systems

MNM designs and manufactures systems for concentrating pineapple juice and coconut water.

The evaporator forms part of the complete processing line. Feed conditions and concentrate outlet requirements are coordinated with upstream preparation and downstream treatment, storage or filling.

Evaporation removes part of the water from a liquid product to increase its concentration. The process prepares concentrates, adjusts solids content and produces ingredients for further processing.

For example, pineapple juice enters an evaporation system as a liquid feed. As water is removed, the remaining juice becomes more concentrated. The final concentration forms part of the product and process design.

Product composition, viscosity, heat sensitivity and concentration requirements influence the equipment arrangement and operating conditions.

MNM designs and manufactures multi-effect falling film long tube evaporators with two to six effects.

The selected arrangement follows the product, water-removal duty, production requirements and available utilities.

1. Product enters the distribution section. Liquid enters at the top and is distributed over the inside surfaces of the heating tubes.
2. A thin film flows down the tubes. Uniform distribution keeps the heating surface wetted as the liquid travels downward.
3. Heat passes through the tube walls. Steam outside the tubes supplies heat, evaporating part of the water in the product. Heating steam and product remain in separate flow paths.
4. Vapour and concentrate are separated. Generated vapour leaves through its own outlet, while concentrated liquid is collected for the following stage.
5. Concentration continues through the selected arrangement. In a multi-effect system, vapour generated in one effect supplies heat to another.

MNM also offers falling film Finishers for products that maintain suitable distribution and film flow during final concentration.

Selection considers the concentrate entering the finishing stage and how its viscosity changes as more water is removed. The product must maintain appropriate flow and heating-surface wetting through to the required final condition.

MNM forced circulation evaporators can serve as the main concentration system or as an FC Finisher following another evaporator.

A circulation pump moves product through the heat-transfer section. Selection follows the product characteristics, incoming concentration, required production duty and final concentration target.

The circulation flow maintains product movement through the heat-transfer section.

This internal flow is different from the feed entering the system or the concentrate leaving it. Circulation requirements serve the heat-transfer duty; feed and concentrate flows define production throughput.

Main evaporation arrangement

Upstream Process → FC Evaporator → Concentrate → Next Process

FC finishing arrangement

Main Evaporator → FC Finisher → Final Concentrate → Next Process

Forced circulation supports duties involving particularly viscous products. Where a plant processes different products, the configuration is evaluated against the incoming condition and final requirement of each product.

Equipment dimensions, circulation requirements, heat-transfer duty and utilities are established for the assigned application.

“Forced circulation” describes the movement of product through the evaporation loop. “Finisher” describes the equipment’s role at the end of the concentration process. MNM selects either falling film or forced circulation for that finishing role according to the product and duty.

A Finisher receives concentrate from the preceding evaporation stage and increases its concentration to the required final level before transfer to the next process.

MNM offers both falling film and forced circulation configurations for this duty. Selection considers the product’s viscosity and flow behaviour throughout the finishing stage.

Falling Film Finisher

A falling film configuration is selected when the concentrate can be distributed evenly and maintain a continuous liquid film over the heating surface.

Product viscosity and its change during concentration are important to maintaining suitable flow and surface wetting.

Forced Circulation Finisher

A forced circulation configuration uses a pump to circulate product through the heat-transfer section.

It is suited to more viscous concentrates where pump-driven circulation provides the appropriate product movement for the finishing duty.

How Viscosity Influences Selection

MNM considers the incoming concentrate, its viscosity at operating temperature, the target concentration and the required throughput.

Selection accounts for product behaviour throughout the finishing stage, including conditions near the final concentration.

The final concentration value alone does not determine the Finisher type. Products with similar solids concentrations can have different viscosities and require different equipment arrangements.

Finishing arrangement

Main Evaporator → Falling Film or FC Finisher → Final Concentrate → Downstream Process

An effect is an evaporation stage within the overall thermal arrangement. Multiple effects allow heat to be reused across the system.

MNM selects the number of effects by considering the product’s temperature constraints, evaporation duty, available utilities, production capacity and operating hours.

Increasing the number of effects can reduce steam consumption, while requiring consideration of additional heat-transfer area and investment. TVR or MVR can also be evaluated as part of the energy design.

TVR uses motive steam to drive a steam-jet thermocompressor. It draws in part of the process vapour and raises its pressure for reuse as a heating medium.

Selection considers the available steam conditions and evaporation duty, with the aim of reducing fresh-steam demand through vapour-energy recovery.

MVR uses a mechanically driven compressor, typically powered by electricity, to raise process-vapour pressure and temperature for heating reuse.

MNM evaluates the evaporation duty, electrical supply, utility costs and operating hours. Start-up or supplementary steam requirements are determined for the selected arrangement.

MNM evaluates the finishing stage, number of effects and vapour-recompression arrangement as parts of one process design.

TVR or MVR can be considered alongside a multiple-effect arrangement where appropriate. Where a Finisher is required, falling film or forced circulation is selected according to the product’s viscosity, flow behaviour and final concentration duty.

The resulting configuration follows the product requirements, available utilities, operating conditions and project investment.