Concentration & aroma · Stage 08
Use a falling-film evaporator for apple juice concentration where short residence time, multiple effects and controlled aroma handling suit the product.
THE PROCESS DUTY
In a falling-film evaporator, juice is distributed as a thin film on the inside of vertical tubes and flows downward while steam or another heating medium raises its temperature. Water evaporates under vacuum. Multiple effects reuse vapour, and a finishing section can reach the target solids. Falling-film designs are common for heat-sensitive fruit juices, but product behaviour and cleaning still determine the configuration.
IN THE LINE
The equipment is only useful when its feed and discharge are defined. These adjacent duties are the first interfaces to review.
WORKING PRINCIPLE
The explanation starts with the material and the process, not a catalogue description.
Juice is spread over the tube surface to create a large area with a relatively short residence time. Distribution matters: dry patches, uneven films or tube blockage reduce performance and can foul the product. Feed distribution and recirculation are part of the design.
Vapour from one effect can heat the next at a lower pressure. More effects generally reduce steam demand but add complexity and require a vacuum system. The optimum depends on utility costs, operating hours and the product.
Volatile aroma compounds can be carried with the vapour, especially in the early concentration stages. A recovery column or condenser may be integrated. The aroma strategy should be fixed before the evaporator layout.
As solids rise, viscosity and fouling potential change. Cleaning intervals, recirculation and the final concentration step must be designed around the actual product. A system that works at low solids may not reach the target without a suitable finishing arrangement.
WHERE IT FITS
WHAT TO WATCH
CONFIGURATION OPTIONS
These are the choices that change the equipment scope. The approved datasheet fixes the final selection.
Number of effects and flow sequence selected from the duty and utilities.
Tube length, diameter and material selected for heat transfer and cleaning.
TVR or MVR option evaluated against steam and power availability.
A final concentration step selected around viscosity and target solids.
Vapour route, condenser and recovery interface included.
SELECTION FACTORS
Bring these points to the equipment discussion. They are more useful than a single throughput number.
Feed flow and solids define the water removal and the number of effects.
Higher solids change film behaviour and heat transfer.
Steam, power, cooling and vacuum determine the operating architecture.
Fouling and CIP requirements affect uptime and product changeover.
SPECIFICATIONS
No catalogue model or performance figure is shown until the configuration is approved. The final datasheet fixes these items.
| Specification area | What is defined in the approved datasheet |
|---|---|
| Capacity basis | Feed flow and water removal at the agreed solids |
| Effects | Number and arrangement selected from the heat balance |
| Vacuum | System and cooling load defined for the duty |
| Aroma | Recovery interface or discharge route included |
| Cleaning | CIP connections, chemical compatibility and access |
| Documentation | Heat and mass balance, general arrangement and datasheet |
Provide your product, capacity basis and available utilities to move from this selection framework to a project-specific datasheet.
TECHNICAL FAQ
If your question depends on the fruit, product or site, include the conditions in the enquiry rather than relying on a general answer.
Send a project enquiryThe thin film and vacuum operation can reduce residence time and thermal exposure compared with some other architectures. The actual benefit depends on the product and the complete system, including pre-treatment, finishing and cleaning.
The number of effects follows the water-removal duty, steam availability, cooling capacity and operating hours. More effects can reduce steam use but increase complexity. A heat and mass balance is needed before choosing.
Viscosity and fouling increase as solids rise. Many systems use a finishing section or a different arrangement for the final concentration step. Confirm the target with the product and the proposed configuration.
Aroma is often recovered from the early vapour streams. The recovery system can be integrated with the evaporator or supplied as a separate scope. The interface and product specification should be agreed before design.
YOUR PRODUCT. YOUR PROCESS.
Tell us the product, the quantity basis and the packaging. We will work back through the process to the equipment scope.