heat exchangers of bioprocess industries


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different types of heat exchangers are used in the bioprocess industries ...there are brief knowledge offew heat exchangers used in such industries.

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heat exchangers of bioprocess industries

  2. 2. HEAT EXCHANGER  They are piece of equipment for efficient heat transfer.  Media may be separated by a solid wall or they may be in direct contact.  They may be used in powerplant petroleum refineries sewage treatment air conditioning……etc  example of Heat exchanger is found in an Internal combustion engine.
  3. 3. TYPES OF HEAT EXCHANGERS • • • • • • • • Shell and tube exchangers. Double pipe exchanger. Plate heat exchangers. Plate-fin exchangers. Spiral heat exchangers. Air cooled: cooling and condenser. Agitated vessels. Fired and heaters.
  4. 4. SHELL AND TUBE HEAT EXCHANGER • Common type of heat exchanger in oil refineries and other large chemical processes. • It consists of shell(a large pressure vessel) and a set of tubes inside the shell known as tube bundle. • One fluid runs through the tube and another fluid flows over the tube to transfer the heat between the two fluids.
  5. 5. • U-TUBE HEAT EXCHANGER FEATURES : configuration gives a large surface area in a small volume. A good shape for pressure operation. Well- established fabrication techniques. It can be easily cleaned.
  7. 7. DOUBLE-PIPE HEAT EXCHANGER • It is made up of concentric inner and outer pipe(sleeve pipe). • Cold and hot liquid respectively flows in the gap of inner pipe and sleeve pipe and hence exchange the heat at same time. • Inner pipe- use U-tube to connect. outer pipe-use direct pipe to connect both ends.
  8. 8. FEATURES: Structure is simple and heat transmission is large. Easy to clean and convenient to assemble and disassemble. Flow rate is appropriate and it is possible to have backwash.
  9. 9. PLATE HEAT EXCHANGER • Use metal plates to transfer heat between two fluids. • Fluids are exposed to much larger surface area because fluid spread out over the plates. this facilitates the transfer of heat. increase the speed of temperature change.
  10. 10. GASKETED-PLATE HEAT EXCHANGER • Consists of a stack of closely spaced thin plates clamped together in a frame. • Thin gaskets seals the plates round their edges. • These exchangers are used in food and beverage industries as they can be readily taken part in cleaning and inspection.
  11. 11. • Plate –heat exchanger FEATURES: Plate thickness -0.5 to 3mm. Gap between plates1.5 to 5mm. Plate surface area range-0.03 to 1.5mm. Plate width: length ratio-2 to 3mm. Maximum flow rate of fluid is limited – 2500m3/h.
  12. 12. CONTINUE…….. ADVANTAGES….. DISADVANTAGES…. • Plates are attractive when material cost is high. • They are easy to maintain. • Low approach temperature can be used (as low as 1 degree C). • They are more flexible. • They are suitable for high viscous material. • They are not in good shape to resist pressure (not suitable for < than 30 bar). • Selection of suitable gasket is critical.
  13. 13. PLATE-FIN EXCHANGERS Plate-fin exchangers consist essentially of plates separated by corrugated sheets, which form the fins. • They are made up in a block and are often referred to as matrix exchangers; • They are usually constructed of aluminum and joined and sealed by brazing. • The main application of plate-fin exchangers has been in the cryogenics industries, • such as air separation plants, where large heat transfer surface areas are needed. • They are now finding wider applications in the chemical processes industry, where large surface area, compact, exchangers are required. Their compact size and low weight have lead to some use in off-shore applications.
  14. 14. SPIRAL HEAT EXCHANGER • They are considered as plate heat exchanger in which plates are formed into a spiral. • Channels are formed between the plates through which fluid flows. • It is made up of long sheets-150-1800mm wide. and gap between sheets- 4-20mm. • Channels are closed by gasketed-end plates bolted to an outer case. • inlet and outlet nozzles are fitted to the case and connect to channels.
  15. 15. AIR COOLED:COOLERS AND CONDENSERS • Air-cooled exchangers should be considered when cooling water is in short supply or expensive. They can also be competitive with water-cooled units even when water is plentiful. Frank (1978) suggests that in moderate climates air cooling will usually be the best choice for minimum process temperatures above 650 c, and water cooling for • minimum processes temperatures below50 C. Between these temperatures a detailed • economic analysis would be necessary to decide the best coolant. Air-cooled exchangers are used for cooling and condensing. • Air-cooled exchangers consist of banks of finned tubes over which air is blown or drawn • by fans mounted below or above the tubes (forced or induced draft).
  16. 16.  Only small rates of heat transfer is required. Storage vessels is used to maintaining the temperature of the liquids. It is also used to promote heat transfer in vessels. AGITATED VESSELS
  17. 17. FIRED HEATERS  These are considered when cooling water is in short supply or expensive.  These are used when high temperature and high flow rates are required.  Capacity of these heaters are 3 to 100MW.  These heaters are directly heated by the products of combustion of a fuel.
  18. 18. APPLICATIONS……… Process feed-stream heaters; 60% of the feed vaporized. Reboilers for the columns used small size direct-fired units. Steam boilers. Reformers for hydrogen production.