Environmental use of evaporators
The increased generation of waste products is an inevitable consequence of economic growth and the diversification of industrial processes. Society demands urgent
solutions to these environmental problems.
Current technology offers diverse solutions depending on the nature of the problem. Biological and chemical treatment processes are not effective where solids are
soluble. Membrane technology also does not provide a good solution. HRS can offer a unique system to achieve separation of solids and liquids in residual waste
treatment.
In these circumstances the only possible option is EVAPORATION. However, current technology for shell and plate type evaporators cannot overcome the main problem.
FOULING on the wall of the heat exchanger due to the formation of residual solids that reduces the heat transfer and consequently, the evaporation capacity.
Treatment of pig slurries
Pig slurries produced in intensive rearing installations constitute a serious environmental problem because of disagreeable odours and potential for ground water
pollution. Their treatment is difficult and costly.
Besides, the Spanish Prevention and Control Law 16/2005 (IPPC, published in the BOE the 2nd of July 2002), requires the evaluation of the emission levels of these
substances to the environment, water and ground for the following activities and installations:
- Production units with more than 40.000 chickens or the equivalent number of other poultry.
- Production units with more than 2.000 breeding pigs with a weight of more than 30 kg.
- Other production units with more than 750 pigs.
HRS Spiratube has developed the Unicus®, a dynamic scraped surface heat exchanger for the thermal treatment of the slurries
where high pressure steam is used to evaporate the volatile elements from the solids. At the end of the process you obtain water, solid residues and ammonia by
separation.
It is common to associate the slurry treatment plant with an electrical cogeneration installation as the residual thermal energy in the exhaust gases from diesel
engines or gas turbines can be used as a source of heat for the evaporation processes in Unicus®.
Other environmental applications
Unicus® is a machine that is outstanding in its versatility and can be used in any heat and mass transfer process in extreme
conditions, such as:
- Recovery of salts in the olive industry.
- Recovery of solvents from the residues from fine chemical production.
- Concentration of reverse osmosis effluents in the leather tanning industry.