Evaporation plants

Evaporation is a technology based on a physical process that finds large and efficient application in treatment of industrial wastewaters, in particular of complex matrix ones, namely containing different typologies of pollutants, for treatment of which the use of other technologies doesn’t allow to obtain satisfying results. Against investment and operating costs that made it one of the most expensive technologies for water depuration, evaporation is able to achieve very high performances, both in relation to quantity (relation between distillate and concentrate) and to quality (chemical-physical characteristics) of the treated water. Evaporation and condensation processes for wastewater depuration can be obtained through the use of different techniques of heating and cooling of the water, such as hot and cold water systems, compression and expansion of gases by an heat pump and mechanical recompression of vapour. Tecam is able to identify the best technological choices both from environmental and economical point of view through careful feasibility studies. The factor mainly bearing on CAPEX (Capital Expenditures) is the material of which plants are made. Evaporators are indeed realized in stainless steel (AISI 316L, DUPLEX) or in metal alloys (HASTELLOY) or in silicon carbide, that guarantee an high resistance to corrosion caused from solutions. Operating costs (OPEX) are determined almost totally from consumptions of electrical and thermal energy, that can nonetheless be reduced thanks to use of undervacuum technology and of multiple effects systems. The recycling of treated water and possible valorization of byproducts favour the Return On Investment.

Hot water/steam evaporators

They use hot water and steam on order to concur the evaporation of the water. For the condensation of the same one, is used tower water or air cooler.

For being able to work they demand evaporation energy (hot), condensation energy (cold). Beyond electrical for users pumps, fans etc.

 

The thermal energy demand diminishes to the increase of the number of effects, and it is:

  • Single effect 600 Kcal (700 Watt/liter) as “hot” thermal source for the evaporation and as many as cold thermal “source”;
  • Double effect 330 Kcal (700 Watt/liter) as “hot” thermal source for the evaporation and as many as cold thermal “source”;
  • Triple effect 220 Kcal (700 Watt/liter) as “hot” thermal source for the evaporation and as many as cold thermal “source”;

They are constructed in several materials which AISI 316L, SAF 2507, Hastelloy, CSi in order to guarantee wide resistance to the corrosion in relation to the characteristics of the solution with which they are in contact.

In relation to the behavior of the solution in phase of concentration and to the specific aim, plate-type heat exchangers, immerse plating, tube and bundle, scraped surface.

In relation to the type of equipment, it is possible to obtain concentrates to the limit of the solubity product, with the presence of sedimentable and suspended materials and also solid materials that have o fixed residual to 105°C > 90%.

Capacities range comprised between 1 mc/d (40 liters/hour) and 240 mc/d (10 mc/hour).

Typical and winning application for the technology when there are in hand waste heat recovery sources, cogeneration.

If it is necessary to produce thermal energy from Natural Gas of LPG or diesel oil it has elevated operational costs.

Heat pump evaporators

It uses technical refrigerant gas to concur the evaporation of the water. For the condensation of the same it is used the same technical refrigerant expanded gas or air cooler.

The necessary energy in order to evaporate is in according to the type of used gas and to eventual thermal recoveries that are possible to carry out.

The demanded energy is only electrical and in relation to the type of product, it is comprised between:

  • 80 Watt/liter
  • 200 Watt/liter

They are constructed in several materials which AISI 316L, SAF 2507, Hastelloy, CSi in order to guarantee wide resistance to the corrosion in relation to the characteristics of the solution with which they are in contact.

In relation to the behavior of the solution in phase of concentration and to the specific aim, plate-type heat exchangers, immerse plating, , tube and bundle, scraped surface.

In relation to the type of equipment, it is possible to obtain concentrates to the limit of the solubity product, with the presence of sedimentable and suspended materials.

This technique does not concur the production of concentrates hat have a fixed residual to 105°C > 90%.

Capacities range comprised between 1 mc/d (40 liters/hour) and 240 mc/d (10 mc/hour).

Typical and winning application for the technology when electrical energy is not much expensive.

Mechanical recompression evaporators

It uses the recompression of steam to concur the evaporation of the water.

The necessary energy in order to evaporate is according to the type of used compressor and to eventual thermal recoveries that are possible to carry out.

The demanded energy I only electrical and in relation to the type of product and it is comprised between:

  • 60 Watt/liter
  • 100 Watt/liter

They are constructed in several materials They are constructed in several materials which AISI 316L, SAF 2507, Hastelloy, CSi in order to guarantee wide resistance to the corrosion in relation to the characteristics of the solution with which they are in contact.

In relation to the behavior of the solution in phase of concentration and to the specific aim, plate-type heat exchangers, immerse plating, tube and bundle.

In relation to the type of equipment, it is possible to obtain concentrates to the limit of the solubity product, with the presence of sedimentable and suspended materials.

This technique does not concur the production of concentrates that have a much elevated fixed residual in relation to the course of the ebullioscopic delta T that modification the thermal-exchange coefficients.

Capacities range comprised between 1 mc/d (40 liters/hour) and 240 mc/d (10 mc/hour).

Typical and winning application for the technology when electrical energy is not much expensive and when the solution to evaporate are much diluted and they don’t tend to form salting & scaling.

Mobile evaporators

Placed inside containers and remotely monitorable, thanks to their characteristics mobile evaporation plants can be easily handled and situated on the outside or in limited spaces. These units meet the needs of rapid interventions, temporary or periodic: they are for example suitable for treatment of water coming from remediation or washing of contaminated soils. For less than three years long intervention periods, rental is the more convenient choice.