FFSI’s Forced Feed Evaporator – When Concentration Is Key

Forced Feed Evaporators (FFE) are an essential component in various industrial processes, offering efficient solutions for concentration and separation tasks. FFS International’s team have successfully implemented numerous FFEs for waste oil and water recycling, however, the versatility of these evaporators extends to a myriad of other industrial applications. This article delves into the benefits and limitations of FFEs, alongside their optimal use cases, to provide a comprehensive understanding of their significance in modern industrial processing.

How Forced Feed Evaporators Work

FFEs operate by using a mechanical pump to circulate liquid through heat exchanger tubes at high velocities. This forced movement ensures consistent flow, minimizing the risk of fouling and scaling on heat transfer surfaces.

Key Components:

1. Heat Exchanger: Transfers heat to the circulating liquid to above the boiling point.
2. Circulating Pump: Maintains high-velocity flow, preventing sedimentation and promoting efficient heat transfer.
3. Separator/Flash Drum: Separates vapor from the concentrated liquid.
4. Condensers: Condense the vapor for reuse or disposal.

Process Flow:

The feed liquid is pumped through the heat exchanger, absorbing heat without boiling within the tubes. The heated liquid enters the separator, where a pressure drop induces rapid vaporization. Vapour is separated, and the concentrated liquid is either recirculated or extracted as underflow.

Out of the top of the FFE the vapour is sent for condensing. This can be done by a cooling system, or the vapour can be run through a multiple effect system or mechanically recompressed to recover energy and reduce running costs.

What Makes Forced Feed Evaporators Special?

Forced feed evaporators are designed to handle challenging feedstocks, including used oils and other industrial fluids, with exceptional efficiency. By leveraging high-pressure feed systems and efficient heat transfer, these evaporators provide unparalleled process performance.

Benefits of FFSI’s Forced Feed Evaporators:

1. High Concentration Efficiency: In applications like oil recovery or in minimising waste, achieving a very high concentration of underflow is crucial. FFEs excel in this aspect by efficiently concentrating the feed liquid to desired levels. FFSI’s design is capable of up to 99% underflow concentration.
2. Handling High Viscosity and Scaling Liquids: FFEs are adept at processing liquids with high viscosity or a tendency to scale. The high-velocity circulation minimizes deposit formation on heat exchanger surfaces, reducing maintenance and operational downtime.
3. Efficient & High Heat Transfer: The forced circulation ensures uniform and very high heat transfer, making FFEs suitable for heat-sensitive materials as large temperature gradients and localised overheating are prevented.
4. Flexible and Scalable: FFEs are suitable for multi-effect and mechanical vapor recompression configurations, which drastically reduce energy demand, and are also easily scalable for system requirements.
5. Robust and Low Maintenance: The high-velocity flow prevents the settling of solids and reduces the risk of fouling, leading to longer operational periods between cleaning cycles. Where required, FFEs can remain largely simple and rugged with few parts and areas of concern.

Limitations of Forced Circulation Evaporators

1. Higher Energy Consumption: The requirement for continuous pumping results in slightly higher energy usage compared to natural circulation systems.
2. Complexity and Initial Investment: FFEs involve more complex designs and higher capital costs due to additional components like pumps and larger heat exchangers. This is normally offset by building internally rather than buying a turnkey unit, which is where FFS International can assist.

Applications of Forced Circulation Evaporators

Oil Recovery

• In oil recovery, FFEs are utilized to concentrate oil-water mixtures, achieving high underflow concentrations (~99%) that facilitate efficient oil extraction and minimize waste.

Chemical and Petrochemical Industries

• Concentration of Caustic Solutions: Efficiently handle and concentrate caustic soda and other chemicals.
• Processing Heat-Sensitive Materials: Ideal for substances that require gentle heating to prevent degradation, such as in the pharmaceutical industry.

Food and Beverage Industry

• Concentration of Purees and Juices: Suitable for high-viscosity and solids containing products like fruit and vegetable purees and dairy products.

Wastewater Treatment

• Handling High TDS Effluents: Effectively concentrate effluents with high total dissolved solids, aiding in zero liquid discharge initiatives
• Efficient waste reduction of liquids and sludges

Looking Ahead

FFEs are integral to processes requiring the concentration of challenging liquids. At FFS International, we offer tailored process solutions designed to meet the specific needs of industries, like achieving very high underflow concentrations using FFEs. Our decades of expertise ensure that clients benefit from efficient, reliable, and cost-effective systems.

For more information on how FFS International can assist with your processing needs, please contact us.