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Intro To Vacuum Systems


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This was one of the very first CBT modules I developed. This presentation was imported into Captivate, where additional features such as mouse-over definitions were added.

Published in: Education, Technology, Business

Intro To Vacuum Systems

  1. 1. FACT Vacuum Systems Introduction Vacuum System Components & Operation
  2. 2. Table of Contents <ul><li>Vacuum System Components & Operation </li></ul><ul><li>Section 1 – Vacuum Overview </li></ul><ul><li>Section 2 – Liquid Ring Vacuum Pumps </li></ul><ul><li>Section 3 – Steam Jet Ejectors </li></ul><ul><li>Section 4 - Condensers </li></ul><ul><li>Summary </li></ul>
  3. 3. Instructions <ul><li>Mouse-over Definitions </li></ul><ul><ul><li>Bright blue text – Mouse pass over and definition will display </li></ul></ul><ul><li>Navigation Bar </li></ul><ul><ul><li>Pause, fast-forward, rewind </li></ul></ul><ul><ul><li>Mute audio </li></ul></ul><ul><ul><li>Exit module </li></ul></ul><ul><li>Links to Procedures </li></ul><ul><ul><li>Click on button to view </li></ul></ul><ul><ul><li>Click on the “X” at top right of the document screen to close </li></ul></ul>
  4. 4. Section 1 <ul><li>Vacuum Overview </li></ul>
  5. 5. Section 1: Learning Objectives <ul><li>Define vacuum </li></ul><ul><li>Recall how operating under a vacuum changes parameters for distillation </li></ul><ul><li>List equipment that can be used to produce a vacuum </li></ul><ul><li>Recognize industrial applications of vacuum </li></ul><ul><li>Select benefits of operating under vacuum </li></ul><ul><li>Distinguish between values of pressure that are considered vacuum and values that are not considered vacuum </li></ul>
  6. 6. Overview <ul><li>What is a vacuum? </li></ul><ul><li>A vacuum is any pressure less than atmospheric pressure </li></ul>
  7. 7. Overview <ul><li>Why use vacuum? </li></ul><ul><li>Certain products decompose or polymerize at high temperatures </li></ul><ul><li>Components can be separated by distillation at lower temperatures when operating under vacuum </li></ul>
  8. 8. Overview <ul><li>Separation of liquids and solids </li></ul><ul><ul><li>Continuous filtration </li></ul></ul><ul><ul><li>Reduced separation time </li></ul></ul><ul><li>Drying </li></ul><ul><ul><li>Lowers drying temperature </li></ul></ul><ul><ul><li>Avoids thermal degradation </li></ul></ul>
  9. 9. Overview <ul><li>To create a vacuum in a system, gas (most typically air) must be removed from the system </li></ul><ul><li>The more gas that is removed; the lower the pressure inside the system </li></ul>
  10. 10. Overview <ul><li>Establishing a vacuum can be accomplished using a single vacuum pump or a combination of types of vacuum pumps </li></ul>
  11. 11. Overview <ul><li>Pressure Value Comparison </li></ul>< 407 = 407 Inches of H 2 O < 760 = 760 Torr < 760 = 760 mm HG < 14.7 = 14.7 PSIA Vacuum Atmospheric Units
  12. 12. Overview <ul><li>This module will focus on </li></ul><ul><ul><li>Liquid Ring Vacuum Pumps (LRVP) </li></ul></ul><ul><ul><li>Steam Jet Ejectors (Venturi Jet) </li></ul></ul><ul><ul><li>A hybrid system, which uses a combination of Steam Jet Ejectors and Liquid Ring Vacuum Pumps </li></ul></ul>
  13. 13. Review Question <ul><li>A vacuum is created when . </li></ul><ul><ul><li>The system is removed from operation </li></ul></ul><ul><ul><li>Air, gas or mass is removed from the system </li></ul></ul><ul><ul><li>Atmospheric pressure is reached </li></ul></ul><ul><ul><li>Residue is removed </li></ul></ul>
  14. 14. Review Questions <ul><li>Select all the following values of pressure that are considered a vacuum. </li></ul><ul><ul><li>14.7 psi gauge </li></ul></ul><ul><ul><li>30 mm Hg absolute </li></ul></ul><ul><ul><li>20 in H 2 O absolute </li></ul></ul><ul><ul><li>5 psi absolute </li></ul></ul>
  15. 15. Section 2 <ul><li>Liquid Ring Vacuum Pumps </li></ul>
  16. 16. Section 2: Learning Objectives <ul><li>Recognize components of the liquid ring vacuum pump </li></ul><ul><li>Select the functions of liquid ring vacuum pump components </li></ul><ul><li>Recall operating principle of the liquid ring vacuum pump </li></ul><ul><li>List functions of the seal liquid in a liquid ring vacuum pump </li></ul><ul><li>Pick out why seal liquid temperature is important </li></ul><ul><li>Recall different configurations of the liquid ring vacuum pump </li></ul>
  17. 17. Liquid Ring Vacuum Pump <ul><li>Simple and efficient with only one rotating part </li></ul><ul><ul><li>A multi-blade impeller on a shaft offset from the pumping chamber </li></ul></ul><ul><li>Pump housing is partially filled with a sealing liquid, typically water </li></ul>Liquid ring
  18. 18. Liquid Ring Vacuum Pump <ul><li>As the impeller rotates, a liquid ring is formed against the inner wall of the pumping chamber </li></ul><ul><li>Because the impeller is offset, the entry depth of the impeller blades into the liquid ring increases and decreases as the impeller rotates </li></ul><ul><li>The area between each impeller blade is called an impeller cell </li></ul>Impeller cell
  19. 19. Liquid Ring Vacuum Pump <ul><li>As the volume of the impeller cell increases, the vapor is drawn in through the suction and then trapped by the liquid ring </li></ul><ul><li>As the impeller continues to rotate, the volume of the impeller cell decreases and the gas is compressed by the liquid ring </li></ul><ul><li>A portion of the liquid is continuously discharged with the compressed gas </li></ul>
  20. 20. Liquid Ring Vacuum Pump
  21. 21. Liquid Ring Vacuum Pump <ul><li>In addition to forming a seal, the liquid ring also absorbs the heat of compression, friction and condensation </li></ul>
  22. 22. Liquid Ring Vacuum Pump <ul><li>A single water ring vacuum pump can only obtain a maximum vacuum of 40-60 Torr or 40-60 mm Hg </li></ul>
  23. 23. Review Question <ul><li>How many moving parts does a liquid ring vacuum pump have? </li></ul><ul><ul><li>Two </li></ul></ul><ul><ul><li>Five </li></ul></ul><ul><ul><li>None </li></ul></ul><ul><ul><li>One </li></ul></ul>
  24. 24. Review Question <ul><li>Select two functions of the liquid ring. </li></ul><ul><ul><li>Seal or trap the gas removed from the system </li></ul></ul><ul><ul><li>React with the process gas </li></ul></ul><ul><ul><li>Absorb heat created inside the pump </li></ul></ul><ul><ul><li>Reduce friction caused by the impeller cell </li></ul></ul>
  25. 25. Liquid Ring Vacuum Pump <ul><li>The temperature of the seal liquid must be maintained below it’s vapor point to prevent cavitation </li></ul><ul><li>Cooling is achieved by continuously adding a cool supply of the sealing liquid </li></ul>
  26. 26. Liquid Ring Vacuum Pump <ul><li>3 basic operating configurations </li></ul><ul><ul><li>Once through or no recovery </li></ul></ul><ul><ul><li>Partial recovery </li></ul></ul><ul><ul><li>Closed loop or total recovery </li></ul></ul><ul><li>All configurations have 4 elements </li></ul><ul><ul><li>Seal liquid source </li></ul></ul><ul><ul><li>Regulating device, to control the flow rate of seal liquid </li></ul></ul><ul><ul><li>Way to stop make-up seal liquid flow when pump is shut off </li></ul></ul><ul><ul><li>Separating device to separate seal liquid/gas mixture </li></ul></ul>
  27. 27. Liquid Ring Vacuum Pump <ul><li>Once-through </li></ul><ul><ul><li>Most basic configuration </li></ul></ul><ul><ul><li>Seal liquid/gas mixture is separated in discharge separator </li></ul></ul><ul><ul><li>Seal liquid is discharged to drain </li></ul></ul><ul><ul><li>Discharged liquid is replaced with fresh seal liquid </li></ul></ul>
  28. 28. Liquid Ring Vacuum Pump <ul><li>Partial Recovery </li></ul><ul><ul><li>Seal liquid/ gas mixture is separated in discharge separator </li></ul></ul><ul><ul><li>A portion of the seal liquid is recovered; remainder is discharged to drain </li></ul></ul><ul><ul><li>Recovered seal liquid is mixed with make-up liquid to maintain constant temperature to the pump </li></ul></ul><ul><ul><li>Excess seal liquid (equivalent to the make-up supply) is discharged to drain </li></ul></ul>
  29. 29. Liquid Ring Vacuum Pump <ul><li>Closed Loop or Total Recovery </li></ul><ul><ul><li>Seal liquid/ gas mixture is separated in discharge separator </li></ul></ul><ul><ul><li>Minimizes liquid waste by recovering seal liquid </li></ul></ul><ul><ul><li>The seal liquid is re-circulated back to the pump via a heat exchanger </li></ul></ul><ul><ul><li>Heat exchanger removes heat from the seal liquid </li></ul></ul><ul><ul><li>Make-up liquid is added as needed </li></ul></ul>
  30. 30. Liquid Ring Vacuum Pump <ul><li>The seal liquid/gas mixture leaves the liquid ring vacuum pump and enters a discharge separator </li></ul><ul><li>Non-condensible gasses and uncondensed vapors vent from the top of the separator to the seal pot </li></ul>From liquid ring vacuum pump To seal pot
  31. 31. Liquid Ring Vacuum Pump <ul><li>Liquid from the separator overflows to the seal pot </li></ul><ul><li>If NO methanol is present, the seal pot overflows to a wastewater sump </li></ul><ul><li>If methanol can contaminate the seal liquid, the seal pot is pumped to a methanol recovery unit </li></ul>From liquid ring vacuum pump To seal pot
  32. 32. Liquid Ring Vacuum Pump <ul><li>Summary </li></ul><ul><li>Used to reduce system pressure less than atmospheric </li></ul><ul><li>Seal liquid absorbs heat of compression, friction and condensation </li></ul><ul><li>Temperature of seal liquid must be below it’s boiling temperature to prevent cavitation </li></ul>
  33. 33. Review Question <ul><li>Why is the temperature of the seal liquid important? Select all that apply. </li></ul><ul><ul><li>To ensure the reaction occurs </li></ul></ul><ul><ul><li>To prevent cavitation </li></ul></ul><ul><ul><li>So the seal liquid will not boil </li></ul></ul><ul><ul><li>So contamination of the seal liquid does not occur </li></ul></ul>
  34. 34. Section 3 <ul><li>Steam Jet Ejectors </li></ul>
  35. 35. Section 3: Learning Objectives <ul><li>Recognize & label the parts of a steam jet ejector </li></ul><ul><li>List 3 advantages of using a steam jet ejector </li></ul><ul><li>Recognize operating principle of a steam jet ejector </li></ul><ul><li>Recall 4 types of steam jet ejectors </li></ul>
  36. 36. Steam Jet Ejectors <ul><li>A steam jet ejector is a simple device used to produce a vacuum </li></ul><ul><ul><li>No moving parts </li></ul></ul><ul><ul><li>Only motive power is steam or gas </li></ul></ul><ul><ul><li>No vibration </li></ul></ul><ul><ul><li>Virtually maintenance free </li></ul></ul><ul><ul><li>Simple to operate </li></ul></ul>
  37. 37. Basic Components <ul><li>4 basic parts </li></ul><ul><ul><li>Steam Chest (1) </li></ul></ul><ul><ul><li>Steam Nozzle (2) </li></ul></ul><ul><ul><li>Mixing Chamber (4) </li></ul></ul><ul><ul><li>Diffuser (5) </li></ul></ul>
  38. 38. Operating Principle <ul><li>Steam Chest </li></ul><ul><ul><li>High pressure steam enters at 1 </li></ul></ul><ul><ul><li>The steam provides the energy to operate the ejector </li></ul></ul><ul><li>Steam Nozzle </li></ul><ul><ul><li>Steam expands through the nozzle (2) to the mixing chamber (4) </li></ul></ul><ul><ul><li>Pressure energy of the steam is converted to velocity energy </li></ul></ul>Steam Chest Steam Nozzle
  39. 39. Operating Principle <ul><li>Mixing Chamber </li></ul><ul><ul><li>Process vapor stream is drawn in at 3 </li></ul></ul><ul><ul><li>The process vapor mixes with the steam in the mixing chamber 4 </li></ul></ul><ul><li>Diffuser </li></ul><ul><ul><li>Both fluids are compressed through the diffuser and discharged at 5 at a pressure higher than the suction pressure </li></ul></ul>Mixing Chamber Diffuser
  40. 40. Review Questions <ul><li>The operating principle of the steam jet ejector is based on . Select all that apply. </li></ul><ul><ul><li>Energy conversion </li></ul></ul><ul><ul><li>Creating energy </li></ul></ul><ul><ul><li>Condensation of steam </li></ul></ul><ul><ul><li>Pressure is converted to velocity </li></ul></ul>
  41. 41. Types of Steam Jet Ejectors <ul><li>Four Basic Types </li></ul><ul><ul><li>Single-stage </li></ul></ul><ul><ul><li>Multi-stage, non-condensing </li></ul></ul><ul><ul><li>Multi-stage, condensing </li></ul></ul><ul><ul><li>Multi-stage with both condensing and non-condensing stages </li></ul></ul>
  42. 42. Types of Steam Jet Ejectors <ul><li>Single stage ejectors </li></ul><ul><ul><li>Simplest design </li></ul></ul><ul><ul><li>Discharge at or near atmospheric pressure </li></ul></ul><ul><ul><li>Capacity is fixed by dimensions; total compression and throughput is limited </li></ul></ul>
  43. 43. Types of Steam Jet Ejectors <ul><li>Multi-stage, non-condensing ejectors </li></ul><ul><ul><li>Low initial cost </li></ul></ul><ul><ul><li>High operating costs due to high steam consumption </li></ul></ul><ul><ul><li>Typically two-stage </li></ul></ul><ul><ul><li>Stages connected directly to each other </li></ul></ul>
  44. 44. Types of Steam Jet Ejectors <ul><li>Multi-stage, condensing ejectors </li></ul><ul><ul><li>Two to six stages </li></ul></ul><ul><ul><li>Use condensers between ejector stages </li></ul></ul><ul><ul><li>Require cooling water for condensers </li></ul></ul><ul><ul><li>Smaller ejectors </li></ul></ul><ul><ul><li>Less steam consumption </li></ul></ul>
  45. 45. Types of Steam Jet Ejectors Cooling Water High Pressure Steam Suction Connection Optional Liquid Ring Vacuum Pump
  46. 46. Types of Steam Jet Ejectors <ul><li>Multi-stage with both condensing and non-condensing stages </li></ul><ul><ul><li>Used for extremely low suction pressures </li></ul></ul><ul><ul><li>Operating pressure between first two stages may be too low to permit condensing </li></ul></ul>
  47. 47. Review Questions <ul><li>Which type of steam jet ejector has the stages connected directly to each other? </li></ul><ul><ul><li>Multi-stage, condensing </li></ul></ul><ul><ul><li>Single stage </li></ul></ul><ul><ul><li>Multi-stage, non-condensing </li></ul></ul><ul><ul><li>Steam jet ejectors are never connected to each other </li></ul></ul>
  48. 48. Section 4 <ul><li>Condensers </li></ul>
  49. 49. Section 4: Learning Objectives <ul><li>Recognize the function of the condenser in a vacuum system </li></ul><ul><li>Recall difference in load to ejector and condenser </li></ul><ul><li>Recognize condenser names and locations of each </li></ul><ul><li>Know how operating pressure of the condenser relates to the discharge pressure of the ejector </li></ul><ul><li>Select why operating pressure of the condenser is important </li></ul><ul><li>List two types of condensers and how they are different </li></ul>
  50. 50. Condensers <ul><li>In an ejector system, the primary purpose of a condenser is to reduce the amount of vapor load that a downstream ejector must handle </li></ul><ul><li>Often the condenser load is ten times the load to the ejector </li></ul>
  51. 51. Condensers <ul><li>Designed to condense steam, organic vapors and to cool noncondensible gases </li></ul>
  52. 52. Condensers <ul><li>Operating pressure must be high enough for condensation to occur </li></ul><ul><li>Condensation of the vapor stream occurs at the discharge pressure of the upstream ejector and the suction pressure of the downstream ejector </li></ul>
  53. 53. Condensers High Pressure Steam Process gas Intercondenser Cooling water
  54. 54. Review Question <ul><li>Why is the operating pressure of the condenser important? Select all that apply. </li></ul><ul><ul><li>So the cooling water is vaporized </li></ul></ul><ul><ul><li>So the gas can be condensed </li></ul></ul><ul><ul><li>So the process reaction will occur </li></ul></ul><ul><ul><li>So the vapor load to the downstream ejector is lowered </li></ul></ul>
  55. 55. Condensers <ul><li>An ejector vacuum system may use a precondenser, intercondensers, an aftercondenser or some combination of these </li></ul>
  56. 56. Condensers <ul><li>Precondenser </li></ul><ul><ul><li>Positioned ahead of an ejector system </li></ul></ul><ul><ul><li>Highly specialized </li></ul></ul><ul><ul><li>Located as close to the process vessel as possible </li></ul></ul><ul><ul><li>Part of the ejector system </li></ul></ul><ul><ul><li>System pressure must be high enough to allow condensation with available water supply </li></ul></ul>
  57. 57. Condensers <ul><li>Intercondenser </li></ul><ul><ul><li>Located between ejector stages </li></ul></ul><ul><ul><li>Reduce the vapor load to the downstream ejector </li></ul></ul><ul><ul><li>First intercondenser is most critical to operation </li></ul></ul><ul><ul><li>Operating pressure directly related to maximum cooling water temperature </li></ul></ul>
  58. 58. Condensers <ul><li>Aftercondenser </li></ul><ul><ul><li>Used after the last stage ejector </li></ul></ul><ul><ul><li>Condensation occurs at atmospheric pressure </li></ul></ul><ul><ul><li>Noncondensible gasses are vented to atmosphere </li></ul></ul>
  59. 59. Condensers <ul><li>Two categories of condensers </li></ul><ul><li>Direct contact or barometric </li></ul><ul><ul><li>Cooling water is sprayed onto and mixes with the vapor stream </li></ul></ul>
  60. 60. Condensers <ul><li>Surface contact or shell-and-tube </li></ul><ul><ul><li>Vapor stream does not come into contact with the cooling water </li></ul></ul>
  61. 61. Review Question <ul><li>In a direct contact condenser the cooling water is . </li></ul><ul><ul><li>Not mixed with the vapor stream </li></ul></ul><ul><ul><li>Mixed with the vapor stream </li></ul></ul><ul><ul><li>Absorbed by the process gas </li></ul></ul><ul><ul><li>A catalyst for the reaction </li></ul></ul>
  62. 62. Summary <ul><li>Operating under vacuum desired to lower boiling point of components </li></ul><ul><li>Liquid Ring Vacuum Pumps </li></ul><ul><li>Steam Jet Ejectors </li></ul><ul><li>Condensers </li></ul>
  63. 63. Post Test Instructions <ul><li>You have completed this module and are ready to complete the post test </li></ul><ul><li>To access the post test, login to the Network Course Management System (NCMS) </li></ul><ul><li>When the list of courses appears, select the “E-test” button </li></ul><ul><li>In the field labeled, “Course”, select “Vacuum Systems” by clicking on the  icon </li></ul><ul><li>Select Vacuum Systems: Introduction Test 1 or Test 2 and click “OK”. </li></ul><ul><li>The test consists of 20 questions </li></ul><ul><li>A score of 80% (16 questions answered correctly) is required for successful completion </li></ul><ul><li>If you have difficulty accessing the post test, contact your trainer </li></ul>