Detailed Equipment Design

Objective:

Attention to Details

How Many Units to Design?

One The More Complex of the Two Short Cut Designs Examples Reactor Distillation Column Absorption Column Dryer

Format for Detailed Design

•

Unit summary - including operating conditions, production rate etc.

–

Mention key design concerns

•

List major assumptions with proper references/justifications

Format for Detailed Design (Cont’d)

•

Present design calculations

–

Improve upon shortcut design wherever possible

–

Design internals in more details (agitators, trays, distributors, heat transfer surface etc.)

–

Select material of construction and calculate wall thickness

Format for Detailed Design (Cont’d)

• • • •

Draw detailed drawing of the equipment with internals Discuss proposed instrumentation and control for the unit including safety device Show proposed instrumentation and control schemes on a separate drawing Prepare a specification sheet

Main Reactor Types

•

Fixed bed

•

Fluidized bed

•

Slurry bed

•

Stirred Tank

Gas Distributor ( A Common Internal) Main Types

•

Ring sparger

•

Perforated Plate

•

Perforated pipe

Gas Distributors (Cont’d) Important Design Considerations

 Uniform flow through distributor orifices  Low pressure drop while avoiding channeling  Avoid plugging due to solid particles  Avoid gas jets impingement on vessel walls – can lead to pitting

Uniform Flow Through Sparger Orifices Criteria:  

f V p



P o

/ 2 

P p



P o

  0 .

1 0 .

1 (1) (2)

Uniform Flow Through Orifices Orifice pressure Drop: 

P o

 2 .

6 

f V o

2 2    1 

By A o V continuity

:

o N o



A p V p A o A p

2   

Substituti ng D o



D p

/  1 

in Eq

.

4 .

04

N

1

o

2  0 .

25

Example of Detailed Design in Guide Book Page 80-86 Example of Gas Distributor Design on Page 77-79