Vapor recompression, mechanical

In Texas, subterranean sulfate brines are pumped to the surface where the brines are first saturated with NaCl before they are cooled by mechanical refrigeration to form Glauber s salt (7,8). This salt is then separated from its mother Hquor, melted, and dehydrated with mechanical vapor recompression evaporators (9). 

Evaporators require a source of heat to operate. This heat may be supplied from a boiler, gas turbine, vapor compressor, other evaporator, or a combination of sources. Multiple effect evaporators are very popular when cheap, high pressure steam is available to heat the system. A Mechanical Vapor Recompression evaporator would use electricity or a gas turbine to drive a compressor that recycles the heat in the evaporator. 

Mechanical textile finishing, 24 622 Mechanical tire shredding, 21 470-472 Mechanical vapor recompression (MVR) crystallizers, sodium carbonate recovery via, 22 789 Mechanics, classical and quantum, 16 734-740... 

The mechanical vapor recompression (MVR) evaporator uses a turbofan compressor to evaporate water that separates the water from dissolved solids. The MVR system discussed in this... 

A variation on standard evaporation technology that is much less energy intensive is the mechanical vapor recompression vaporization process. This uses the same evaporation... 

To improve the LoHeat process, a fifth stage of solution flashing was added along with mechanical vapor recompression (MVR) to boost the fifth-stage flashed steam back to the pressure of the regenerator column. The combination of ejectors plus MVR for multi-stage heat recovery is referred to as the Benfield Hybrid LoHeat Process. If this improvement is combined with ACT-1 activator the energy consumption can be reduced to 600 kcal/Nm3 of C02 removed. 

MJ/kWh (10,400 Btu/kWh), mechanical vapor recompression can vaporize 1 kg of water for less than 0.46 MJ (1.0 lb for less than 200 Btu). The Carver-Greenfield process is based on combining mechanical vapor recompression with multiple-effect evaporation to dry high-water-content biomass and other solid suspensions. Many full-scale units have been placed in operation since the first facility was installed in 1961. One unit was used at the Hyperion wastewater treatment plant in Los Angeles from 1987 to early 1995 to dry 40 t/day of biosolids wetcake to 99+% total solids content (Haug, Moore, and Harrison, 1995). The process has since been replaced by rotary steam dryers because it was not possible to reach the design capacity of the unit. 

A chart to estimate the costs of ejectors for thermocompression has been developed.Approximate costs of compressors for mechanical vapor recompression also can be found. In addition, these publications contain details of cost estimation for heat exchangers. For more detailed estimation of cost of shell-and-tube exchangers, see Purohit. " Plate-and-frame and spiral-plate heat exchanger costs can be estimated using Kumana. " ... 

Mechanical vapor recompression for temperatures <20°C, ranging from 10 to -62°C. Refrigeration capacity 20 to 5000 kW. 

As the cost of energy has increased in recent years, attention is again being directed to mechanical vapor recompression, which by its nature, permits substitution of electrical energy for evaporation and crystallization rather than requiring heat energy (steam). A typical recompression crystallizer flow sheet is shown in Figure... 

When steam drying is used in situations where there is no demand for waste energy in the form of low-pressure steam, mechanical vapor recompression (MVR) can be applied... 

Extension of heat pump technology to large-scale continuous operations and temperatures above 120°C points to water vapor as a working fluid, provided steam compression can be done efficiently. In such a system, water evaporated from material being dried is compressed and used for heating incoming material. The principle of operation is similar to the well-known mechanical vapor recompression (MVR) systems. 

FIGURE 54.9 Mechanical vapor recompression + 1 (MVR + 1) Carver-Greenfield process configuration (1) fluidizing tank (2) MVR stage (3) separator (4) vacuum system (5) final evaporator stage (6) oil separation system (7) deoiler and (8) centrifuge. 

By means of evaporation, dissolved pollution is concentrated with the aim of obtaining distilled purified water from wastewater. In mechanical vapor recompression (MVR), the influent is inserted in the system, where it is distributed across heat elements and as a consequence is partly evaporated. This vapor is compressed by a compressor and is then transported to the inner surface of the heat element where it condenses and is collected. The concentrated wastewater is deposited onto the bottom of the device and is subsequently transported by the concentrate pump, after which the cycle starts all over. The technique is effective (ca. 99%), which is dependent on the influent and the type of pollution. 

Zhou, Y., Shi, C., Dong, G., 2014. Analysis of a mechanical vapor recompression wastewater distillation system. Desalination 353, 91-97. 

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