What is the difference between msf and med

Abstract The multi-effect distillation MED process is the oldest process in desalination. References and patents have existed since , more than years ago. Vertical tubes, horizontal tubes … Expand. Optimization of multi-effect distillation process using a linear enthalpy model. Abstract This paper presents a novel mathematical formulation for modeling-based optimization of the multiple effect distillation MED water desalination process using thermal vapor compression … Expand.

AbstractThe main goal of this paper is to simulate the performance of Multiple Effect Desalination MED units in operation to predict the influence of variation of different input parameters on the … Expand. Predicting part load performance of small MED evaporators : a simple simulation program and its experimental verification.

Abstract Most of the studies on MED systems have dealt mainly with the design problem where the number of effects, top brine temperature and seawater temperature are specified and the heat transfer … Expand. Thermo-economic analysis and optimization of a vacuum multi-effect membrane distillation system.

Abstract Vacuum multi-effect membrane distillation is an advanced system that possesses the features and merits of vacuum membrane distillation and multi-effect distillation.

It has low operating … Expand. Chapter 10 — Economic Analysis of Desalination Processes. Single and dual stage closed-loop pressure retarded osmosis for power generation: Feasibility and performance.

Model calculations … Expand. Multi-stage flash desalination: present and future outlook. As the turning point of … Expand. Multiple-effect evaporation desalination systems. Abstract Seawater desalination by parallel feed multiple-effect evaporation has a simple layout in comparison with other multiple-effect or multistage desalination systems.

Several operating … Expand. Related Papers. Buros, et. Englewood, N. Water vapor is drawn from the evaporation chamber by a compressor and except in the first stage is condensed on the outsides of tubes in the same chambers, as is shown in Figure The heat of condensation is used to evaporate a film of saline water applied to the insides of the tubes within the evaporation chambers.

Buros, et al. Englewood, New Jersey, U. The process works by using a specialized membrane which will pass water vapor but not liquid water. This membrane is placed over a moving stream of warm water, and as the water vapor passes through the membrane it is condensed on a second surface which is at a lower temperature than that of the feedwater.

Specifically, they derive their source of thermal energy from steam that has been used for other purposes, usually for power generation. Thus, the feedwater is heated in a boiler to a high energy level and passed through a steam turbine before the steam is extracted for use at a lower temperature to provide the heat required in the distillation plants. At this point, the desalination then conforms to the processes described above.

They also provide freshwater to agricultural communities. At that time, those units were among the largest in the world. The Federal Electricity Commission currently operates about 31 desalination plants to produce high-quality boiler make-up water, and maintains the two dual-purpose units in Tijuana.

The Mexican Navy also installed some smaller solar distillation plants to provide a supply of freshwater to some islands in the Pacific Ocean. PEMEX, the national oil company of Mexico, operates about 62 small seawater desalination plants for human freshwater consumption on off-shore oil platforms or ships. These distillation units are mainly VC, waste heat, submerged-tube evaporators, and RO plants. Both use the MSF process. Operation and Maintenance Most plants are installed in isolated locations where construction is troublesome and where the availability of fuel, chemicals, and spare parts is limited.

In these places, there is usually also a scarcity of qualified personnel; therefore, people are often selected from the local communities and trained to operate the plants. The operation of distillation plants requires careful planning, well-trained operators, and adequate operation and maintenance budgets to guarantee the supply of good quality water. Except for an annual shutdown of 6 to 8 weeks for general inspection and maintenance, the operation of desalination plants is usually continuous.

Level of Involvement The manufacturing capacity to produce MSF evaporators is available in those places where power plant equipment is fabricated. Thus, many countries in Latin America have the potential to manufacture locally the equipment needed to develop desalination plants. Further, some local manufacturers have signed licensing agreements with major foreign desalination manufacturing firms as a result of governmental policies of import substitution, in order to offer desalination equipment, particularly MSF plants, to the electric-generating industry in the region.

In die Caribbean, desalination by distillation is being used primarily in the private sector, especially in the tourist industry. Some industrial concerns and power companies have incorporated distillation into their operations as part of a dual process approach.

Government participation has been very limited. Future developments of this technology, which are expected to reduce the cost of desalination plants, will be likely to encourage greater government participation in the use of distillation in the development of public water supply systems. Costs The production cost of water is a function of the type of distillation process used, the plant capacity, the salinity in the feedwater seawater or brackish water , and the level of familiarity with the distillation process that exists in the region.

Table 7 shows a range of costs that have been reported by different countries using this technology. Production costs appear to increase in proportion to the capacity of the plant. Virgin Is. MED and VC 4. The MSF system has proved to be a very efficient system, when properly maintained. Because the water is boiled, the risk of bacterial or pathogenic virus contamination of the product water is minimal.

Although MED is an older technology than the MSF process, having been used in sugar refineries, it has not been extensively utilized for water production. Cultural Acceptability Despite significant progress toward becoming more energy-efficient and cost-effective, the level of community acceptance of distillation technologies is still limited. Their use is mainly restricted to resort hotels and high-value-added industries, and to the Caribbean islands. Further Development of the Technology Research into the falling or spray film MED thermal desalination process suggests that further development of distillation technologies can produce product waters that are comparable in quality to those produced with current MSF technologies and also offer additional advantages, including lower pumping requirements, higher heat transfer rates, and greatly reduced pressure differentials across the heat transfer surfaces.