Evaporation Project

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Related Links: Falling Film Evaporation (FFE4) Project

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Example 1: Evaporation Project - using Flash Tanks and Heat Exchanges

Project Location

This is a Steady State project and is stored at:
..\SysCADXXX\Examples\10 Alumina\Evaporation with Cooling Tower Example.spf

Features Demonstrated

1. Shows the use of Bayer3 properties model.
2. Shows how to set up a multistage Flash Trains.
3. Shows how to set up Barometric Condenser
4. Shows how to set up a Cooling Tower.
5. Shows how to set up a simple PGM file.
6. Shows how to set up PID controls.
7. Shows how to set up Annotation Blocks.

Brief Project Description

• Weak Spent liquor is concentrated via evaporation of water through 9 stages of flashing.
• A majority of the circuit is under vacuum.
• Live steam heater is added to heat up the liquor feeding to the first flash tank.
• A barometric condenser is used to condense the flash vapour from the last stage.
• A cooling tower is set up to cool the hotwell mixture.
• PID controllers are used to adjust the steam and cooling water additions.
• Cooling tower water make up is calculated using the PGM file.

Project Configuration

• Spent Liquor Feed to the project is defined using the DefineLiquor option.
• Spend Liquor feed location is to the last stage.
• The steam addition to the circuit is set as a cascade control, to meet a target concentration on the output stream. (Alternatively controls can be modified to control the evaporation rate)
• The set up of the flash stages are as per the Digestion Projects.
• The Barometric water addition is used to control the cold end temperature.
• The Cooling water make up is to counter for losses in the cooling tower (evaporation and blow down loss)
• The cooling tower is set up:
  1. Using the Merkel method
  2. User defined outlet Air Wet buld Temperature
  3. User defined Liquid to Gas Ratio
  4. User defined tower characteristic factor
  5. Cooling tower will estimate the require air flow and energy
• Steam economy and cooling water make up side calculations are done in the PGM file.

Included Excel Reports

1. Evaporation.XLS - this excel report show some basic report formats for the project, these include Input Criteria and simple overall balance and Stream data report