003_Heat_Exchangers and coolers, heaters

003_Heat_Exchangers and coolers, heaters

1. المبادلات الحرارية

2. الحرارة الكامنة للتصعيد

3. اليات انتقال الحرارة التوصيل الحمل الاشعاع

4. الحمل

5. تاثير سرعة المائع

6. الاشعاع

7. كم طريقة لانتقال الحرارة تراها في الصورة؟

8. العزل الحراري

9. Thermal Insulation Has to fulfill one or more of three functions Reduce thermal conduction in material where heat is transferred by molecular or electronic motion. Reduce convection currents which can set up in liquid or air spaces. Reduce radiation heat transfer where heat is transferred by electromagnetic waves.

10. خامات العزل الحراري

11. Examples Thin aluminum foil can be used in building walls, and reflecting metals on roofs reduce the heating effect of the sun. DEWAR Flasks provide insulation through evacuated double-wall arrangement in which the walls have reflective silver or aluminum coatings.

12. HEAT FLOW RESISTANCE Air heat resistance is 1500 times higher than that of a good thermal conductor such as silver or aluminum, and 30 times than that of glass.

13. Classification Flow Direction: Parallel, Counter, and Cross flow. Depending on the state of the media in the heat exchanger: liquid/liquid, Gas/ Gas, and Liquid/Gas. Purpose: Evaporator, Cooler, Chiller, .. Etc. Construction: Double Pipe, shell and tube.

14. المبادلات الحرارية

15. تبادل الحرارة

16. U-type Double pipe Heat Exchanger

17. Shell and Tube Heat Exchanger

18. TEMA STANDARD

19. FLOATING TUBESHEET

20. FLOATING TUBESHEET

21. REAR END

22. Shell and Tube heat exchanger, counter-crossflow, one tube pass and one shell pass

23. PLUGGING

24. Construction Outside shell Tubes placed inside. Attached at the front and rear ends in tube sheets Baffles are placed to redirect the shell fluid past the tubes.

25. FLOW PASSAGES INSIDE THE SHELL

26. TUBE ARRANGEMENT

27. FOULING

28. Fouling of Heat Exchangers Forming of deposits on heat transfer surfaces, which interferes with heat transfer or fluid flow. Due to higher thermal resistance, less heat is transferred. Due to reduced pipe cross section, pressure drop increases and more energy is expended in pumping. In now way two exchangers are similar in fouling, there exists several types of fouling.

29. WHICH FLUID INSIDE AND WHICH OUTSIDE THE TUBE Non fouling fluids should be routed inside the tube. Fouling fluids should be reserved for shell side duties.

30. Precipitation Fouling Part of dissolved salts will crystallize on heat transfer surfaces.

31. Particulate Fouling Gas or liquid contains solid particles (such as sand and dust), which separates mostly due to gravity, and attaches to heat transfer surfaces.

32. Chemical Reaction Fouling Deposits are formed as a result of chemical reaction within the fluid. Heat transfer surface is not consumed itself in the reaction, although it can act as a catalyst. A common problem in petroleum refining.

33. Corrosion Fouling The metal surface itself is a reactant and is consumed in the reaction.

34. Solidification Fouling When heat transfer surface temperature is low enough, the flowing fluid (or one of its constituents) can freeze at the surfaces.

35. Biological Fouling Biological macro or micro-organisms, sticks to heat transfer surfaces, and grows

36. MECHANICAL CLEANING

37. Spiral Heat Exchanger

38. Spiral Heat Exchanger

39. Advantages

40. Disadvantages

41. Plate-and-Frame Heat Exchanger

42. Common Gasket Material

43. Heat Exchanger Tube Rupture Particularly when the low pressure side is liquid filled, in the event of tube rupture, the high pressure fluid will flow through the ruptured tube and can quickly overpressure the low pressure side of the exchanger. Dynamic simulation determines the relief device size and location.

44. Air coolers

45. Air Cooled Heat Exchangers Heat is transferred from process fluid to ambient air. Fins are employed to increase heat exchange surface. Bonding method may determine the maximum operating temperature.

46. FAN POSITION

47. LOAD CONTROL

48. Fins bonding methods Metallurgical: Welding, Brazing, Soldering to the tube. Mechanical: Imbedded (grooved tubes) or Mechanically integrated.

49. Advantages

50. Disadvantages

51. Components Tube Bundle Tube sheet:

52. High Efficiency aerofoil Axial Impeller

53. Parallel Flow, Double Pipe

54. Counterflow, Double Pipe