Boiler Blow down control
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Boiler Blow-down System Improvement Design Team: Todd Fitzgerald Brian Parris Matt Van Horn Sponsor: Air Products and Chemicals, Inc. Advisor: Dr. Dick Wilkins
Transcript of Boiler Blow down control
Boiler Blow-down System
Improvement
Design Team:
Todd Fitzgerald
Brian Parris
Matt Van Horn
Sponsor: Air Products and Chemicals, Inc.
Advisor: Dr. Dick Wilkins
Background
APCI Paulsboro manufactures catalysts and prepolymer chemicals for:
Polyurethane foams
Elastomers
Adhesives
A boiler produces steam to heat the processes used to make these
chemicals
System Diagram
Blow-down System
The blow-down system removes suspended and dissolved solids from boiler to help prevent:
Scale formation
Carryover
Corrosion
Types of Blow-downs
Continuous surface blow-downEliminates surface scum
Intermittent bottom blow-down Front and Rear blow-downs
Removes heavy particulates
Intermittent sight glass blow-downClears sight glass
Helps maintain proper operation of level sensors
Flash Tank
Large Volume to
allow phase
separation
Vents steam to
atmosphere
Hold-up volume to
cool hot water
Mission Statement:
To improve the steam boiler
blow-down system and ensure
the system is in compliance with
state regulations.
Initial Investigation
Benchmarking
Toured University of Delaware boiler facilities
Researched proper operation of blow-down systems
Interviewing
APCI Personnel
Outside Experts
Testing and Data Collection
Water samples at various points in the boiler system
Identification of Problem Areas
Boiler Blow-Down System
Cooling System Flash Tank PipingValves
Prioritization of Problem Areas
Kepner-Tregoe Diagram to quantify importance of problems
Reveals that the flash tank and cooling system are a priority
Kepner Tregoe
Problem ImpactEase of
Implementation
Ability to
DiagnoseRate
Flash Tank 5 4 5 100
Cooling system 5 3 4 60
Pipes 3 4 1 12
Valves 2 5 1 10
Primary Problem
Flash Tank
Currently undersized
Water ejects from the
vent
No hold up volume
Drain pipe is
undersized
Customers and Wants
Artis Williams
Plant Manager
Jim Long
Process Engineer
Joe Tropea
Boiler Operator
George Wentz
Boiler Supervisor
Dave Sylvester
Maintenance Supervisor
Maintain Compliance
Cost Effective
Reliable
Easy to implement
Non Labor Intensive
Accessible
Simple
Constraints
New Jersey Administrative Code Flash tank outlet temperature: < 150 F
Flash tank outlet pipe: Area twice inlet pipe area
New Jersey Pollutant Elimination System Water discharged to the sump: < 95 F
Shut down Boiler isolation
October 26th thru 29th
Concepts
Flow-Rate Calculations
Need for Shut Down Testing
Shutdown Testing
Boiler Blow-Down
Experiment
Level Drop vs. Time
Typical blow down: 5/8” level drop in 15 sec
Result: 125 gal/min
Outlet Temperature CalculationsAssumptions:
No heat transfer
Piping and flash tank do not heat up
Water level does not change in flash tank
Concept Selection
Metrics
Target
Values
Outlet
Temperature95 F
Cost $30,000
Years of use 10 Years
Number of
Components
2
Components
Time between
blow downs12 Hours
Time to
implement4 Days
Space around
components3 Feet
Number of steps
to operate4 Steps
Total
Holding tank
with Cooling
Holding tank
w/o cooling
Inline
Cooling
5 5 5
1 2 4
3 4 5
1 2 5
5 5 5
2 3 5
1 1 4
5 5 4
23 27 37
Final Concepts
Cooling Method Selection
Proof of ConceptBlow-down system model to validate outlet
temperature calculations
Proof of Concept
Procedure
Set flow rates
Fill tanks
Measure initial
temperatures
Open isolation
valves
Record outlet
temperatures
Analytical Model Verified
Final Concept
Flash Tank Dimensions
Diameter = 54 in
Height = 8 ft
Hold Up Vol = 376 gal
Cooling water is added
to flash tank and outlet
pipe
“Demolition and Removal”
Diagram
Shows what existing
equipment needs to
be removed to
implement new
design
“Work in Progress”
Shows changes to the
existing Process and
Insturmentation
Diagram (P&ID)
Design Hazard Review
Purpose: Identify all possible problems and hazards with new design
People Involved
Process Engineers
Piping Specialists
Maintenance Personnel
Boiler Operators
DHR Results
Potential
ProblemsSolutions
Burn hazardGuards / open
area
Code
Violation
Temperature
monitor
Silt build upAddition of valves
/ flanges
Cooling water
controlAddition of valves
Cost Estimate
Flash Tank $8,000
Minor Equipment $700
Installation Estimate $10,000
Detailed Engineering $10,000
Total $28,700
Transition Plan
Team 1 Deliver all necessary paper work to APCI for final
review
APCI Install suggested system during April shut down
Monitor operation of new system
Investigate cause of valve and piping failure
Summary
Evaluated and identified primary problems
Developed and selected best possible solution with UDesign
Concept proved with analytical model which was verified through experimentation
Completed the first steps for APCI design review
Provided transition plan with cost estimate for new design
Questions?
Operating Procedure
Check flash tank water temperature
Open drain cooling water valve and shut flash
tank cooling water valve
Perform blow-down
Close drain cooling water valve and reopen flash
tank cooling water valve
Hazop Deviation Matrix
Extra pictures
Extra Pictures
Extra Pictures
Extra Pictures
Extra Pictures
Extra Pictures
