What are the disadvantages of multiple-effect evaporator?
Disadvantages are:
- high head-room requirements.
- higher pressure drop through the tubes than in a falling film evaporator.
- hydrostatic head at the bottom of the tubes may increase product temperature and cause temperature-sensitivity problems.
How can you increase the efficiency of a multiple-effect evaporator?
Diagnosis involves leakage detection in MEE by vacuum testing and hydro testing followed by high pressure cleaning along with chemical cleaning to remove the scaling in the evaporator which will improve the efficiency of the MEE.
How does multi effect evaporator work?
A multiple-effect evaporator uses the water vapor from one effect as the heating medium for the next effect, which operates at a lower boiling point. The latent heat in water vapor can also be reused by thermally or mechanically compressing the vapor to a higher pressure and temperature.
What is multistage evaporator system?
A Multi Stage Evaporator, as defined in chemical engineering, is an apparatus for efficiently using the heat from steam to evaporate water. In a multiple-effect evaporator, water is boiled in a sequence of vessels, each held at a lower pressure than the last.
What is the difference between single effect evaporator and multiple effect evaporator?
Evaporators are classified by the number of effects. In a single-effect evaporator, steam provides energy for vaporization and the vapor product is condensed and removed from the system. In a multiple effect arrangement, the latent heat of the vapor product off of an effect is used to heat the following effect.
How many evaporators are attached in multiple effect evaporator?
It is highly economical when compared with a single effect. About 5 evaporators can be attached.
What is parallel feed mechanism in multiple effect evaporation?
Parallel feed in multiple-effect evaporators involves the adding of fresh feed and the withdrawal of concentrated product from each effect. The vapor from each effect is still used to heat the next effect.
What is the reason for using decreasing pressure on every subsequent effects in a multiple effect evaporator?
2. What is the reason for using decreasing pressure on every subsequent effects in a multiple effect evaporator? Explanation: The main reason to reduce the pressure is to be able to decrease the boiling point so that the previous effect’s vapour can evaporate the water in this effect.
In which application are multi evaporators used?
Originally designed for concentrating sugar in sugar cane juice, it has since become widely used in all industrial applications where large volumes of water must be evaporated, such as salt production and water desalination.
Why is multi stage compression used?
Explanation: Due to the use of high-pressure compression by a single-cylinder, there are chances of obtaining very high discharge temperatures which might heat the cylinder head or burn the lubricating oil. Hence, Multistage compression provides effective lubrication.
Why multiple effect evaporator is better than single effect evaporator?
Multiple-effect evaporators can remove much larger amounts of solvent than is possible in a single effect. In a multiple effect arrangement, the latent heat of the vapor product off of an effect is used to heat the following effect.
What are the advantages of using multi effect evaporator over single effect evaporator?
Explanation: Advantages of multiple effect evaporators are suitable for large scale and for continuous operation. It is highly economical when compared to single effect. Multiple effects are used to minimize the energy input required to evaporate undesirable water content.
How does a multiple effect evaporator work?
In a multiple-effect evaporator, water is boiled in a sequence of vessels, each held at a lower pressure than the last. Because the boiling temperature of water decreases as pressure decreases, the vapor boiled off in one vessel can be used to heat the next, and only the first vessel (at the highest pressure) requires an external source of heat.
Who is the author of multiple effect evaporator?
CERTIFICATE This is to certify that the project entitled “Design and simulation of a Multiple effect evaporator using Vapor bleeding” is an original work done by MonalishaNayak, Roll No. 108CH001, under my guidance and supervision. National Institute of Technology, Rourkela
When to use sensible heat in multiple effect evaporator?
Multiple effect evaporation commonly uses sensible heat in the condensate to preheat liquor to be flashed. In practice the design liquid flow paths can be somewhat complicated in order to extract the most recoverable heat and to obtain the highest evaporation rates from the equipment.
How long is the payback period for five effect evaporator?
Annual savings of $43,200 in the cost of steam is achieved. The payback period of the modified design of five effect evaporator system is found as 2 years 5 months and 12 days. 10 CONTENTS