Small distillation column - Revision history

137.215.116.180: /* Advanced Process Control */

2013-11-29T05:09:01Z

‎Advanced Process Control

2013-11-29T05:07:44Z

‎Operating Problems

2013-11-29T05:06:20Z

‎Recent Improvements

2013-11-29T05:04:44Z

‎Recent Improvements

2013-11-29T05:01:53Z

‎Available Instrumentation and Final Control Elements

2013-11-29T04:59:46Z

‎Operating Region

2010-11-09T21:36:20Z

2010-11-09T21:33:17Z

2010-11-09T20:26:39Z

2010-11-09T20:25:15Z

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 ==Advanced Process Control==
-Several advanced process control software packages have been implemented on the column:
+Several advanced process control software packages have been implemented on the column: Fuzzy Logic control (2013), Honeywell RMPCT (2010), Generic Simulink Based MPC (2010), Aspentech DMC Plus (2008)
-Honeywell RMPCT (2010), Generic Simulink Based MPC (2010), Aspentech DMC Plus (2008)
+and Aspentech SmartStep (2008).The associated software can be found in the following directories (newest last):
-and Aspentech SmartStep (2008).The associated software can be found in the following directory:
+[ftp://ragnarok.up.ac.za/publicftp/lab/Rigs/05_Distillation/2010][ftp://ragnarok.up.ac.za/publicftp/lab/Rigs/05_Distillation/2013]
 [ftp://ragnarok.up.ac.za/publicftp/lab/Rigs/05_Distillation/2010]

@@ Line 29: / Line 29: @@
 [[File:PB090165.JPG|300px|right|thumb|Flooding on bottom tray]]
-Flooding is the biggest problem encountered during the column operation. Flooding usually start on the bottom tray and then propagates up to stage 1.  Rusted bubble cap trays and faulty downcomers may be the factors responsible for this tendency. At high vapour flow rates, reversal of flow in the feed section is sometimes encountered.
+Flooding is the biggest problem encountered during the column operation. Flooding usually start on the bottom tray and then propagates up to stage 10.  Downcomers that are too close to the next tray may be a primary factor responsible for this tendency. At high vapour flow rates, reversal of flow in the feed section is sometimes encountered.
 ==Advanced Process Control==

← Older revision		Revision as of 05:06, 29 November 2013
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	The intermediate feed drum has been removed and the column is now directly fed from the combined products receiving drum. This eliminates the feed drum level control problem which could not be automated in the past due to lack of a feed valve.		The intermediate feed drum has been removed and the column is now directly fed from the combined products receiving drum. This eliminates the feed drum level control problem which could not be automated in the past due to lack of a feed valve.
		+
		+	The insulation applied in 2010 has been removed. The resulting high internal reflux results in the azeotropic composition of the ethanol/water mixture being easily achieved in the distillate.

	==Operating Problems==		==Operating Problems==

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 ==Recent Improvements==
 A pump has been installed in the bottoms product line. The increase in head has dramatically improved the dynamic performance of the bottoms product control valve. Temporary insulation of the column with paper towels and aluminium foil has increased the temperature obtained throughout the column with 12 °C. It also offers the advantage of being hazard free and easily removable.
 ==Operating Problems==

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 ==Available Instrumentation and Final Control Elements==
-Several measurements are available on the column. Temperature measurements are available on all the trays. Differential pressure cells on the reboiler and feed drum can be used for level calculations.
+Several measurements are available on the column. Temperature measurements are available on all the trays. A differential pressure cell on the reboiler can be used for level calculations. The level in the distillate drum is inferred via image processing on teh floating yellow ball.
-There are three control valves. The control valves are situated on the reflux, bottoms and top product lines. The reboiler is equipped with a robust electrical heating element.
+There are three control valves. The control valves are situated on the reflux, bottoms and top product lines. The reboiler is equipped with an electrical heating element whose duty is controlled via a thyristor.
 ==Recent Improvements==

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 The small distillation column has a very narrow operating region. The exact constraints will depend on the specific base-layer setup. During the 2010 CML732 project the maximum plate 10 temperature that could be maintained
 while keeping column stable, was 81 °C. The maximum reflux IP transducer signal that could be implemented while still maintaining column stability was 14 mA. The exact IP signal will however depend strongly on the calibration of the IP transducer. A feed mixture of 30% ethanol provided the most operational flexibility.
-−
 ==Available Instrumentation and Final Control Elements==

@@ Line 15: / Line 15: @@
 '''Recent Improvements'''
-AA pump has been installed in the bottoms product line. The increase in head has dramatically improved the dynamic performance of the bottoms product control valve. Temporary insulation of the column with paper towels and aluminium foil has increased the temperature obtained throughout the column with 12 °C. It also offers the advantage of being hazard free and easily removable.
+A pump has been installed in the bottoms product line. The increase in head has dramatically improved the dynamic performance of the bottoms product control valve. Temporary insulation of the column with paper towels and aluminium foil has increased the temperature obtained throughout the column with 12 °C. It also offers the advantage of being hazard free and easily removable.
 '''Operating Problems'''