Evaporation is an operation used to remove a liquid from a solution, suspension, or emulsion by boiling off some of the liquid. It is thus a thermal separation, or thermal concentration, process. We define the evaporation process as one that starts with a liquid product and ends up with a more concentrated, but still liquid and still pumpable concentrate as the main product from the process. There are actually a few instances where the evaporated, volatile component is the main product, but we will not discuss that here.
In most cases it is essential that the product is subject to no thermal degradation during the evaporation process, requiring that temperature and time exposure be minimized. This and other requirements brought on by the physical characteristics of the processed product have resulted in the development of a large range of different evaporator types. Additional demands for energy efficiency and minimized environmental impact have driven development toward very innovative plant configurations and equipment design. Our technology is supported by several test and development facilities, where the technology is being continually refined, improved, and applied to new products.
During the design of evaporation plants, numerous, sometimes contradictory, requirements have to be considered. They determine which type of construction and arrangement is chosen, and the resulting process and economic data. The most important requirements are as follows:
• Capacity and operational data, including quantities, concentrations, temperatures, annual operating hours, change of product, controls automation, etc.
• Product characteristics, including heat sensitivity, viscosity and flow properties, foaming tendency, fouling and precipitation, boiling behavior, etc.
• Required operating media, such as steam, cooling water, electric power, cleaning agents, spare parts, etc.
• Capital, operating, and other costs
• Personnel costs for operation and maintenance
• Standards and conditions for manufacture, delivery, acceptance, etc.
• Choice of materials of construction and surface finishes
• Site conditions, such as available space, climate (for outdoor sites), connections for energy and product, service platforms, etc.
• Legal regulations covering safety, accident prevention, sound emissions, environmental requirements, and others, depending upon the specific project.
In the field of thermal separation / concentration technology, evaporation plants are widely used for concentration of liquids solutions.
The major requirement in the field of evaporation technology is to maintain the quality of the liquid during evaporation and to avoid damage to the product. This may require the liquid to be exposed to the lowest possible boiling temperature for the shortest period of time.
Numerous other requirements and limitations have resulted in a wide variation of designs available today. In many evaporators the heating medium is steam, which heats a product on one side of a heat transfer surface. Other heat sources such as thermal oil and hot water can also be used as the heating medium.
The following list contains links to descriptions of common types of evaporators, and the ones that we most frequently design:
• Falling Film Evaporators
• Forced Circulation Evaporators
• Plate Evaporators
• Skid Mounted Evaporators
• Thermal and Mechanical Vapor Recompression (TVR & MVR)
• Wiped Film Evaporators
• Multiple Effect Distillation Evaporators
• Thin Film Evaporators
• Vacuum Evaporators
• Thermally Accelerated Falling Film Evaporators
• Evaporative crystallizers
• Cooling Crystallizers
