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