How are evaporators designed?

How are evaporators designed?

Evaporator design consists of three principal elements: heat transfer, vapor-liquid separation, and efficient utilization of energy. In our sugar industry the solvent is juice, heat is supplied by condensing steam, and the heat is transferred by indirect heat transfer across metallic surfaces.

What are the requirements to be fulfilled by an evaporator?

A properly designed evaporator must, at a minimum: Be designed to effectively transfer heat at a high rate with minimum surface area to be cost-effective for installation,operations and maintenance. Effectively separate the vapor from the liquid concentrate. Meet the conditions required by the product being processed.

What is the most common evaporator design?

Finned Tube It is the most widely used type of evaporator. These particular metals are chosen because of their heat transfer abilities and cost. The fins absorb the heat moving across them (convection) and, through conduction, transfer the heat to the copper.

What is the formula of evaporator capacity?

Explanation: Economy of an evaporator is defined as, E = Capacity/Consumption = (30/45) x 100 = 66.7 = 67%. 4. What is the Evaporator Consumption if we evaporate 10kg of water from a feed of 50kg at a temperature of 25℃ to a final temperature of 100℃ in an hour? Hence the Evaporator Consumption = 20kg/hr.

What is the principle of evaporator?

The evaporator works the opposite of the condenser, here refrigerant liquid is converted to gas, absorbing heat from the air in the compartment. When the liquid refrigerant reaches the evaporator its pressure has been reduced, dissipating its heat content and making it much cooler than the fan air flowing around it.

What are the types of evaporator?

The types of evaporators in this category include:

  • Climbing Film Evaporator.
  • Short-tube Vertical Evaporator.
  • Basket-type Evaporator.
  • Long-tube Vertical Evaporator.
  • Plate Evaporators.
  • Horizontal Tube Shell-Side Evaporator.

What is an evaporator PDF?

• Evaporator: A device used to transform liquid form of a. chemical substance (i.e. water) into its gaseous/vapor form. • Evaporation: Operation used to concentrate a solution. containing non-volatile solute and volatile solvent. • Design of evaporators: Characteristics of solute and solvent.

Which type of evaporator is best?

The long-tube vertical, or rising-film, evaporator (Figure 4) is one of the most widely used tubular evaporators….Advantages of the long-tube vertical evaporator are:

  • Reduced floor space requirements.
  • Relatively high heat-transfer coefficients due to partial two-phase flow.
  • Ability to handle foamy liquids.

What are the parts of evaporator?

The main components of a rotary evaporator are: A motor unit for rotating the evaporation flask or vial that contains the user’s sample. A vapor duct serving as the axis for sample rotation, and a vacuum-tight conduit for the vapor to be drawn off the sample.

How is evaporator length calculated?

If the evaporator must move 400 gallons per minute: 14 x 400 = 5,600. Multiply the answer by 500: 5,600 x 500 = 2,800,000. This answer is the evaporator’s size, measured in BTUs per hour. Divide the answer by 12,000: 2,800,000 / 12,000 = 233.33.

What is evaporator efficiency?

Thermal efficiency of evaporators The measure of thermal efficiency of an evaporator train is called the steam economy (unit of water evaporated per unit of steam used) and the steam economy is directly related to the number of thermal effect in the train. Modern evaporators typically have 6 or 7 thermal effects.

What is evaporator temperature?

Evaporation temperature is the temperature at which the refrigerant evaporates and boils in the evaporator, which corresponds to the evaporation pressure. Evaporation temperatures are generally 2-3 °C lower than the required water temperature.

What is evaporator pressure?

The evaporating pressure is the pressure at which the refrigerant is phase changing from a liquid to a vapor. This phase change is referred to as evaporation or vaporizing, thus the term evaporating pressure.

What is the principles of evaporation?

Evaporation is a process, which is used to separate the solid substance which is dissolved in liquid. The principle of the evaporation process is that liquid vaporizes easily, whereas solids do not.

What are the four types of evaporators?


  • Natural/forced circulation evaporator.
  • Falling film evaporator.
  • Rising film (Long Tube Vertical) evaporator.
  • Climbing and falling-film plate evaporator.
  • Multiple-effect evaporators.
  • Agitated thin film evaporators.

What is TD temperature?

Dew Point Temperature (Td) Dew point temperature is a measure of atmospheric moisture. It is the temperature to which air must be cooled in order to reach saturation (assuming air pressure and moisture content are constant).

How do I calculate BTU for evaporator?

Why low pressure steam is used in evaporator?

This is because more evaporation is done in the first effect at low concentration, and less evaporation in the subsequent effects at higher concentration where the heat transfer coefficient is lower.

What are types of evaporation?

What is Delta in HVAC?

“Delta T” is the most common use of the word ‘delta’ in the HVAC industry, meaning temperature difference. If the temperature before a cooling coil is 75°F and the temperature after the cooling coil is 55°F, subtract 55°F from a 75°F to find a Delta T of 20°F.

What are the factors to consider when choosing an evaporator?

The type of evaporator or heat exchangers, forced or natural circulation, feeding arrangement, boiling point elevation, heat transfer coefficient, fouling, tube size and arrangement are all very important. Types of evaporators have already been discussed and the guidelines for selection of most suitable evaporator are addressed in the next section.

What are the methods of feeding of evaporator?

Methods of feeding of evaporator: a: forward feed; b: backward feed; c: mixed feed; d: parallel feed. 4. PERFORMANCE OF EVAPORATORS (CAPACITY AND ECONOMY) The performance of a steam-heated evaporator is measured in terms of its capacity and economy. Capacity is defined as the number of kilogram of water vaporized per hour.

TYPE OF EVAPORATORS Evaporator consists of a heat exchanger for boiling the solution with special provisions for separation of liquid and vapor phases. Most of the industrial evaporators have tubular heating surfaces. The tubes may be horizontal or vertical, long or short; the liquid may be inside or outside the tubes. 2.1.

What are the characteristics of a single effect evaporator?

METHODS OF FEEDING OF EVAPORATORS Evaporators are classified by the number of effects. In case of a single-effect evaporator, the vapor from the boiling liquor is condensed and the concentrated product is withdrawn from the bottom of the evaporator.