Evaporation.
HRS Heat Exchangers applies its heat exchanger technology for evaporation application. Both corrugated tube heat exchangers
(K series) and scraped
surface heat exchangers (Unicus
series) have been used with great success for evaporation purposes.
The standard way of operating of our evaporators is with forced recirculation.
In this setup, a recirculation pump is used to pump the fluid through the evaporator (at many times the flow rate of the
evaporator feed). This way the fluid velocity is maintained high and elevated heat transfer coefficients are obtained in
the evaporator. The forced recirculation evaporator is of special interest for applications with viscous fluids. The higher
the viscosity, the worse the heat transfer becomes. Therefore recirculating with higher flow rates (by using the recirculation
pump) maintains heat transfer high and keeps the evaporator design relatively small.
Scraped surface evaporation.
For many environmental applications, standard evaporation technologies (falling film etc) often cannot deliver the desired
performance. As the concentration of solids increase during the evaporation process, the risk of fouling substances depositing
on the tube wall increases. A fouled evaporator will drop quickly in heat transfer. The result is underperformance and the
unit will have to be put offline for cleaning. Repeated downtime is not beneficial to the plants economic balance.
The solution HRS Heat Exchangers proposes is the Unicus scraped surface evaporator. We have the capacity to supply evaporators
up to 100 square meters (1080 square feet) of heat transfer area. This allows us to provide solutions for heavy fouling
applications in evaporation with large evaporation capacity. No other company in the world can deliver this performance
with a fouling free operation guaranteed.
Multi effect evaporation & integration with dryer plant.
With multi effect evaporation an optimal way of using the available energy for evaporation can be obtained. In multi effect
evaporation, the evaporated water in the first effect is used as heating media in the second effect. This process can be
repeated several times. This way of 1 kg of steam invested can evaporate several kg of steam from the product. HRS Heat
Exchangers applies multi effect evaporation wherever possible. Combinations of multi effect evaporation and steam compression
(mechanical vapor recompression or thermo compression) can be supplied as well for further energy optimization.
Another possibility of energy optimization is combining an evaporator plant with a dryer plant. These solution works well
for cases where an (environmental) waste stream is separated in solid phase and a liquid phase by mechanical separation
(centrifuge, decanter). The solid phase is sent directly to an indirect dryer. The liquid phase is send to the evaporators.
As energy for the evaporators we take the evaporated water of the dryer plant. The concentrate from the evaporator is mixed
with the solid phase prior to sending to the dryer. This way of operating reduces to a maximum the volume of the environmental
waste in the most energy efficient way possible.
Video.
This video shows how HRS applies its scraped surface technology for environmental waste concentration. Evaporation is an
effective way of reducing the volume of environmental waste streams. Often, these waste streams cause fouling of process
equipment when they are heated up. By using scraped surface heat exchangers this problem can be overcome.
Applications.
Our applications:
Environmental:
Biomass and biofuels:
Food industry: