1 / 10

CHEN 4470 – Process Design Practice

Distillation Modeling. CHEN 4470 – Process Design Practice Dr. Mario Richard Eden Department of Chemical Engineering Auburn University Lecture No. 13 – Design of Overhead Condensers and Air-cooled HX February 16, 2012 Material Developed by Dr. Jeffrey R. Seay, University of Kentucky - Paducah.

Download Presentation

CHEN 4470 – Process Design Practice

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Distillation Modeling CHEN 4470 – Process Design Practice Dr. Mario Richard EdenDepartment of Chemical EngineeringAuburn University Lecture No. 13 – Design of Overhead Condensers and Air-cooled HX February 16, 2012 Material Developed by Dr. Jeffrey R. Seay, University of Kentucky - Paducah

  2. Overview • Purpose of Overhead Condensers • Provide reflux flow to the top of a column and acts as an additional theoretical stage above the trays/packing • Types of Condensers • Knock-back reflux • Total condenser • Partial condenser Proper condenser design is critical to the optimum operation of a column!

  3. Knock-Back Condenser • This design is easy to operate, but difficult to achieve precise control. • Condenser will be larger due to the bi-directional traffic on the process side. • Condenser can be in the vertical or horizontal position. • Elevation is critical. 2-Phase Flow Region • Horizontal – Process on the shell side. • Vertical – Process is on the tube side.

  4. Partial Condenser Vapor Distillate • Used when vapor product is required, or if non-condensible gases are present in the overhead product. • Controlling the vapor stream split can be challenging. • Condenser can be in the vertical or horizontal position. • Horizontal – Process on the shell side. • Vertical – Process is on the tube side. • Elevation is not critical. Liquid Distillate

  5. Total Condenser • Total condensers are used when no non-condensable gases are present. • As with other condensers, vertical or horizontal operation is possible. • Elevation is not critical for a total condenser. • Subcooling of the reflux can be a problem with overhead condensers, especially with vertical designs. Liquid Distillate

  6. Condenser Design • Considerations • The overhead condenser is often a critical part of the control concept of a column • Because distillation is based on VLE principles, the overhead condenser can be used to control the temperature and pressure in the column • A later lecture will present some control concepts and strategies for overhead condensers • Condensers in series can also be used to optimize utility consumption

  7. Condensers in ASPEN Plus

  8. Air-Cooled Heat Exchangers • Typical Air-Cooled Condenser Tube Detail Design Equations: Air-cooled HX are primarily used when no other cooling utilities are available on site Note: The surface area, A, includes the area of the fins! C and m are parameters based on the size of the fin.

  9. Air-Cooled HX Design • Design Considerations • Natural convection in turndown cases • Changing ambient air conditions • Effect of precipitation on operation of unit • Possibility of water-hammer inside tubes • Possible Control Parameters • Air flow across the tube bank • Position of louvers on top of the unit • Liquid level inside the tubes

  10. Other Business • Next Lecture – February 21 • Equipment sizing and pinch analysis

More Related