Page 891 - Flipbook_SolidDesignSoutheast2020

Evaporators

EnErgy EConomy EnErgy rECovEry
process optimization has long been one of dedert’s specialties. as the price of energy has risen over the years so have efforts
Each dedert Evaporator system is systematically configured to increased to find reusable energy. dedert has long been a
provide the Customer with the quickest return on their investment pioneer in waste heat recovery and was granted the us patent for
with the lowest operating cost. an evaporator chest with built in scrubber for the corn wet milling
industry.
EnErgy sourCEs for Evaporation
Steam Heated Multiple Effect Gas Heated Hot Water
the energy source is steam at a condensing temperature in many cases, off-gases from existing plant operations such another waste energy source that can exist in a plant environment
above that which exists on the process side of the heat transfer as dryers or scrubbers contain valuable energy which may be is hot water (such as condensate). dedert has designed and
surface. for cases where evaporation requirements are small recovered as the energy sources for gas heated evaporators. supplied evaporators that use the sensible heat from process
or steam is relatively inexpensive, single effect evaporators this essentially “free” energy provides for very low operating streams as the energy source.
are used. in this case, the vapors produced are rejected to a cost. also, with the reduction of the waste gas stream exiting the
condenser. for higher evaporative duties or when steam is evaporator, energy requirements are reduced downstream for the
relatively expensive, additional “effects” are used and the process emissions handling equipment as well.
vapors are condensed in subsequent effects operating at lower
pressures. Evaporation rate, steam cost, layout area and product installation costs are lower. the replacement of required steam Organic Vapor
characteristics are used to determine the economy and ultimately with recycled vapor results in lower operating costs making this there are cases in many plants where process vapors other than
the optimum number of effects. a viable choice in many applications. this is a very attractive water vapor are generated. rather than dissipating the latent heat
option for larger evaporation rates.
Mechanical Vapor Recompression of these vapors using cooling water in a condenser, they are often
used as the energy source to drive evaporation.
dedert originally introduced mechanical vapor recompression to Thermal Vapor Recompression
the corn wet milling industry decades ago. as a way to reduce energy consumption, a thermocompressor in the Biofuel industry, for example, ethanol vapor from
which uses high pressure steam as a motive fluid is added rectification and molecular sieves is sometimes used as an energy
these evaporator components are similar to steam driven to a typical steam heated evaporator. the motive steam at source to drive the stillage evaporator. given a sufficient quantity,
machinery with the addition of a mechanical compressor. approximately 150 psig enters the thermocompressor and expands flash vapors or turbine exhausts are also a welcome source of
mechanical energy supplied via a compressor or fan compresses as it passes through a diffuser. this in turn entrains recycled vapor recoverable energy.
the process vapor to a higher pressure (and condensing and discharges it at an intermediate pressure while providing a
temperature) where it is reused as the heating steam. steam and steam rate reduction. steam is once again the source of energy.
cooling water requirements are significantly reduced and are Economics and product characteristics determine the suitability of
eliminated in many cases. thermal vapor recompression Thin Stillage Evaporator
mvr evaporators are generally operation. this design Decanter Vapor to Next Effect
more costly than steam driven Feed provides improved steam Whole Stillage
evaporators, but because the economy with less costly
operating economy is greatly equipment than straight steam Cake Ring Dryer
improved, operating costs Compressed vapor heated designs but requires RTO
are significantly less. fewer higher pressure steam.
vessels are required than Vent Vapor WHE
in steam powered multiple Steam
effect systems; therefore, chest
Concentrated
Separator Stillage
Vapor
Process Compressor Dryer and Evaporation Integration
condensate Product
Product
aftEr salEs
Evaporators Mechanical Vapor Recompression
dryErs
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