Plate Falling Film Evaporator (PFFE) is efficiently developed for optimizing evaporation of sugar solutions with full accessibility of the heat transfer surfaces. PFFE has the lowest pressure losses and higher turbulence on liquid side to achieve the highest heat transfer coefficient. Due to very high heat transfer rate of these evaporators, evaporation from a sugar solution at very low ∆T can be easily accomplished. It provides flexible capacity merely by adding more plate packs/units, shorter product residence time resulting in a superior quality concentrate, a compact design with low installation cost.
PFFE is the most advanced tool which completely reformed the bleeding scheme and back pressure requirement of the evaporator set. PFFE is suitable for heat/temperature sensitive material. During the plate evaporation process, liquid is pumped between thin plates with the heating medium on the mating surfaces. The product is then evaporated with vapor generation forming a high velocity core. This expansion in volume causes high velocity, thin film on the heat exchange surface providing efficient heat transfer.
- Lowest pinch temperature difference for minimum utility consumption.
- Highest heat transfer rate (up to 4500 W/m 2 K).
- Offers highest energy efficiency.
- Efficient entrainment separator (More than 90% removal of 5µm size particles).
- Allows accommodation of more number of effects in given ∆T and ∆P.
- Compact and modular design.
- Distributed heating surface that facilitates easy operation and maintenance.
- Low thermal residence time.
- Lower inversion and low color formation.
- Low recirculation pumping requirement.
- Having experience of designing, manufacturing, erection & successful commissioning of Standalone 10,000 m2 HSA in Single Unit.
- Patented technology.
The design of the PFFE functioning as a single or multi-effect evaporator has the following significant technical and economic advantages:
The short height plate pack/unit patterns and narrow gaps allow for very high turbulence at relatively low fluid velocity and reduction in vapour piping from one evaporator effect to another. The reduced travel distance & time of vapours help wrestling pressure losses and hence it provides energy efficiency. Short height plate packs together with downward spraying of evaporative liquid above the plate pack arrangement reduce frictional losses and enhance the natural draft at an increased velocity. It also has lower pumping power consumption due to low recirculation of juice.
PFFE enables evaporation at lowest ∆T (1-4˚C), which further eliminates the need of high pressure steam and consequently reduces scale formation due to low pressure as solubility of calcium salts (responsible for scale formation) is higher at reduced temperature. This also reduces inversion and colour formation in processing heat sensitive liquids like sugar juice thereby minimizing sugar losses. Because of the lowest delta T, recovery of waste vapour lost in conventional process can be recovered, to use for further application till the lowest possible sink temperature.
Plate evaporator can also be designed for once through operation with suitable design improvement which is not possible in any other type of evaporator. The short heat contact period resulting from single pass operation and low liquid holdup eliminates product deterioration even when highly heat sensitive liquids are involved. The resulting concentrate is of the highest quality possible. The variety of plate evaporators allows custom concentrates to be produced. Even 80% total solids or better is possible depending on feed material characteristics.
A significant benefit of the plate evaporator is that it is expandable; allows to accommodate more number of effects in given ∆T and ∆P with increased heat transfer capability. By simply adding or removing plate units, varying evaporation rates may be achieved. Large expansions are possible with additional frames and plate units.
The short heat contact period resulting from single pass operation and low liquid holdup eliminates product deterioration even when highly heat sensitive liquids are involved. The resulting concentrate is of the highest quality possible.
Due to plate modular arrangement, plate unit is easily removed from tie bolts and slides back; the movable plate units then can be inspected, cleaned or removed for refurbishment if necessary. Also all stainless steel surfaces within the plate units are fully accessible for easy cleaning. Normal CIP is done with low consumption of cleaning chemicals due to the low liquid holdup.
The high efficiency also makes it possible to reach close approach temperatures which are particularly important in heat recovery and regeneration applications.
Very high turbulence is achieved due to plate technology, many contact points and narrow gaps between the plate units. This combined with the smooth plate surface reduces fouling considerably as compared to other types of evaporators.
A high heat transfer coefficient means less heat transfer area and smaller heat exchangers. This results in less space requirements, reduced flow rates, and smaller pumping means.
Due to modular & compact design assembly with least structural requirements. Very small product is actually in the plate evaporator at any time. This permits rapid start-up and shutdown with minimal waste. Small quantities of product may be processed economically.
High structural integrity and reduced weight of the apparatus due to its modular structure and compact assembly is possible.
All stainless steel surfaces within the plate packs are fully accessible for easy cleaning. Normal CIP is done with low consumption of cleaning chemicals due to the low liquid holdup.
Due to the compact size and low weight, no cranes or special foundations are required for installation. Typically, an existing building on site is suitable and installation time is minimal.
- For low to high evaporation rates,
- For temperature-sensitive products,
- For highly viscous products,
- For extreme evaporation conditions,
- For product circulation design.
The main application is with products that are highly heat sensitive and therefore benefit from the high HTC’s and low residence time.
- Sugar/Beet Industry
- Sugar Refinery
- Food Industry
- Pharmaceutical Industry
- Water Treatment Plant