1. Fans & Heaters technical seminar
Centrifugal Fan Retrofit Presentation
Brian Carson Aftermarket Retrofit Team Leader

2. Howden Centrifugal Retrofits
Subjects Covered 1
What is a Retrofit – Defining the Problem and Solution 2
Example 1 – Seal Issue on GR Fan 3
Example 2 – Fan Performance Issue 4
Example 3 - Flow Control Issue on FD Fan 5
Defining the Value – By Savings and by Cost

3. Retrofits and Enhancements
What is a Retrofit?

4. Retrofits and Enhancements
What is a Retrofit?
Retrofit
A complete replacement fan or impeller installed on existing foundation.

5. Retrofits and Enhancements
What is a Retrofit?
Retrofit
Enhancement
A complete replacement fan or impeller installed on existing foundation.
The existing fan impeller or auxiliaries are modified to change performance.

6. Typical Problems with Centrifugal Fans

7. Typical Problems with Centrifugal Fans
Process limitations
Misalignment
Too much volume
Rotating stall
Not enough volume flow
To much time repairing
Replacing parts
Catastrophic Failure
Problems With Centrifugal Fans
High vibration
Cost increase
Fatigue cracking
Excessive erosion
High bearing temperatures
Lack of control
Lost production
Leakage of flue gas
Bearing failure
Excessive corrosion
Increased power consumption
Fouling of Impeller

8. The simplified retrofit process
What is a Retrofit
The simplified retrofit process

9. The simplified retrofit process Component Reliability Issue
What is a Retrofit
The simplified retrofit process
Current Situation
Performance Issues
Component Reliability Issue

10. The simplified retrofit process
What is a Retrofit
The simplified retrofit process
Current Situation
Performance Issues
Component Reliability Issue
Desired Situation
Optimised Performance
Increased Equipment Availability

11. The simplified retrofit process
What is a Retrofit
The simplified retrofit process
Current Situation
Performance Issues
Component Reliability Issue
Desired Situation
Optimised Performance
Increased Equipment Availability
Howden Solution

12. The simplified retrofit process
What is a Retrofit
The simplified retrofit process
Current Situation
Performance Issues
Component Reliability Issue
Desired Situation
Optimised Performance
Increased Equipment Availability
Howden Solution
All retrofit opportunities can generally be reduced down to performance issues and/or reliability issues.

13. Issues: causes, consequences and Howden solutions
Fan Reliability
Fan Reliability Issues
Process/Flue
Gas Leak
Erosion
Corrosion
High Vibration
Consequences
Increased corrosion on fan shaft at seal and on fan casing etc around leak area.
H&S issue for local personnel. (Poisonous, hot or explosive gas)
Reduced Performance.
1. Reduced impeller life. 2. Risk of impeller failure Reduced performance.
1. Damage to equipment Risk of impeller failure.
Main causes
Leakage from:
1. Seals
2. Expansion Joints
3. Holes in casing
Impeller/casing not designed for current level of abrasive particles in process gas.
Fan has not been properly maintained during it service life.
Impeller/casing not designed for corrosive environment.
Fan has reached the end of its design life.
1. Imbalance or misalignment
2. Fouling
3. Structural/ Rotor dynamic issues.
Howden Solutions
1. Replace seals with upgraded Howden design.
2. Replace Expansion Joints.
3. Repair/replace casing.
1. Add abrasive resistant or sacraficial materials to equipment to protect main components. 2. Replace worn components with new parts designed for increased errosion protection.
Replace corroded components with new parts designed for increased corrosion protection.
1. Contact Howden Services for balancing/alignment service. 2. Clean impeller and contact Howden Services for balancing service. 3. Perform vibration analysis and replace defective part or fan with Howden replacement.

14. Issues: causes, consequences and Howden solutions
Fan Performance
Fan Performance Issues
Lack of Fan Control
Not Enough performance
Changed Performance
Too Much Performance
Consequences
Limited process output.
Loss of revenue.
Reduced availability.
1. Limited process output Loss of revenue.
1. Limited process output Loss of revenue. 3. High energy costs.
Main causes
1. Seized flow controls.
2. Problem with actuator and/or linkages.
1. Fan undersized at design Process demands have changed.
1. Process system has changed. 2. Operating density has changed.
1. Fan over sized at design Process demands have changed.
Howden Solutions
1. Install Howden design flow control.
2. Replace actuator and/or linkages.
1. New Howden impeller in existing casing Fan on existing foundations

15. What is a Retrofit
Reliability Issues
Performance Issues

16. What is a Retrofit
Reliability Issues
Performance Issues
Flue Gas Leakage
Erosion
Corrosion
High Vibration

17. What is a Retrofit
Reliability Issues
Performance Issues
Flue Gas Leakage
Erosion
Corrosion
High Vibration
Low Performance
Performance Changed
High Performance

18. What is a Retrofit
Reliability Issues
Performance Issues
Flue Gas Leakage
Erosion
Corrosion
High Vibration
Low Performance
Performance Changed
High Performance
Lack of Fan Control

19. GRF Fan Seal Issue at PP in KSA
Example 1

20. GRF Fan Seal Issue in KSA
Example 1
Power Plant in KSA
Problem Summary
MHI FGD fans leaking gas at casing seal.
MHI seal difficult to set and maintain. Unacceptable down time for fan/boiler.
Gas leakage a health hazard to personnel.
Accelerated corrosion of components when leaked gas condenses to form acid.

21. Component Reliability Issue
GRF Fan Seal Issue in KSA
Example 1
Power Plant in KSA
Problem Summary
MHI FGD fans leaking gas at casing seal.
MHI seal difficult to set and maintain. Unacceptable down time for fan/boiler.
Gas leakage a health hazard to personnel.
Accelerated corrosion of components when leaked gas condenses to form acid. =
Component Reliability Issue

22. GRF Fan Seal Issue in KSA
Example 1
Power Plant in KSA
Desired Improvements
Client wished to achieve:
100% sealing of boiler flue gasses.
Easy set up and maintenance to reduce fan/boiler down time.
Reduce unplanned outages to fix seals.

23. GRF Fan Seal Issue in KSA
Example 1
Power Plant in KSA
Desired Improvements
Client wished to achieve:
100% sealing of boiler flue gasses.
Easy set up and maintenance to reduce fan/boiler down time.
Reduce unplanned outages to fix seals.
Howden Solution
Howden would perform a retrofit of the current MHI casing seals and replace with a Howden designed purged double carbon ring seal.

24. GRF Fan Seal Issue in KSA
Example 1
Power Plant in KSA
Issues with Labyrinth Seal Type
1±0.3 mm clearance between labyrinth brush and labyrinth ring.
Potential wear of labyrinth brush.
Reduced sealing and escape of gas.
Difficult for seal setting and maintenance.
Labyrinth Seal

25. GRF Fan Seal Issue in KSA
Example 1
Power Plant in KSA
Benefits of Howden Seal Retrofit
100% gas sealing due to high pressure purge air.
“Floating seal” arrangement accepts thermal expansions.
Increased radial clearance prevents shaft & seal housing contact.
Double Carbon Ring Seal

26. GRF Fan Seal Issue in KSA
Example 1
Power Station in KSA
Howden replaced the original seals arrangement with the following equipment:
Double carbon ring seal, in stainless steel housing, with purge air
Stainless steel seal carrier to connect to fan casing.
Stainless steel shaft sleeve.
Purge air filter and regulator.
Cast aluminum cooling disk.
Howden also provided onsite Technical Assistance during installation and commissioning phase of the project.

27. GRF Fan Seal Issue in KSA
Example 1
Power Station in KSA
Before installation of Howden designed shaft seal
After installation of Howden designed shaft seal

28. After installation of Howden designed shaft seal
GRF Fan Seal Issue in KSA
Example 1
Power Station in KSA
After installation of Howden designed shaft seal

29. GRF Fan Seal Issue in KSA
Example 1
Power Station in KSA
Outcome
All seals (16 off) successfully operating since 2014
Saving approx 1 week down time per year per boiler.

30. PA Fan Performance Issue at PP in Malaysia
Example 2

31. PA Fan Performance Issue in Malaysia
Example 2
Power Station in Malaysia
Problem Summary
Environmental legislation changes meant improvements were required to the combustion in the boiler.
New coal mill required in each boiler.
Current volume flow from Howden Primary Air fans not enough for additional mill.

32. = Performance Issue PA Fan Performance Issue in Malaysia
Example 2
Power Station in Malaysia
Problem Summary
Environmental legislation changes meant improvements were required to the combustion in the boiler.
New coal mill required in each boiler.
Current volume flow from Howden Primary Air fans not enough for additional mill. =
Performance Issue

33. PA Fan Performance Issue in Malaysia
Example 2
Power Station in Malaysia
Desired Improvements
Client wished to achieve:
Primary Air Fan to deliver increased volume flow to accommodate an additional mill.
Retain and reuse the existing fan foundations, casing and motor.
Carry out improvement work during normal shutdown.

34. PA Fan Performance Issue in Malaysia
Example 2
Power Station in Malaysia
Desired Improvements
Client wished to achieve:
Primary Air Fan to deliver increased volume flow to accommodate an additional mill.
Retain and reuse the existing fan foundations, casing and motor.
Carry out improvement work during normal shutdown.
Howden Solution
Howden would perform a retrofit of the current Howden impeller, with a larger impeller of the same family.

35. PA Fan Performance Issue in Malaysia
Example 2
Power Station in Malaysia
Performance Guarantees and Testing
The end user required an increase of 5 % volume to achieve the minimum flow requirements of the new mill.
Howden carried out fan performance testing before and after the retrofit to determine the level of improvement in performance.
This testing determined if Howden had exceeded the minimum guaranteed increase of 5%.
The test results over 2 off fans ranged from 5.3 to 7.6 %. This indicated that the minimum target had been exceeded.

36. PA Fan Performance Issue in Malaysia
Example 2
Power Station in Malaysia
Outcome
The test results for the 2 off fans of the 1st boiler indicated that the 5% target had been exceeded.
The end user then contracted Howden to roll out the same solution on the 4 off fans on the remaining 2 off boilers.
After installation and testing, all fans achieved a volume increase of 5.3 to 7.6 % on volume flow.

37. FD Fan Flow Control Issue at PP in KSA
Example 3

38. FD Fan Flow Control Issue in KSA
Example 3
Power Plant in KSA
Problem Summary
Boldrochhi Forced Draught Fan flow controls sticking.
Causing limitation of fan volume output, limiting boiler output.
Unplanned down time and maintenance unacceptable.

39. Performance and Component Reliability Issue
FD Fan Flow Control Issue in KSA
Example 3
Power Plant in KSA
Problem Summary
Boldrochhi Forced Draught Fan flow controls sticking.
Causing limitation of fan volume output, limiting boiler output.
Unplanned down time and maintenance unacceptable. =
Performance and Component Reliability Issue

40. FD Fan Flow Control Issue in KSA
Example 3
Power Plant in KSA
Desired Improvements
Client wanted:
Flow controls to work fully and freely and allow full fan and boiler performance to be achieved.
To reduce and eliminate unplanned maintenance and down time.

41. FD Fan Flow Control Issue in KSA
Example 3
Power Plant in KSA
Desired Improvements
Client wanted:
Flow controls to work fully and freely and allow full fan and boiler performance to be achieved.
To reduce and eliminate unplanned maintenance and down time.
Howden Solution
Howden would perform a retrofit of the current Boldrochhi flow controls and replace with a Howden designed Inlet Louvre Damper.

42. Boldrochhi Radial Vane Control
FD Fan Flow Control Issue in KSA
Example 3
Power Plant in KSA
Issues with Flow Control
Sand/dust entrained in air clogging the lubricating/wear parts in the flow control leading to seizing.
Seized parts are inside fan meaning fan must be turned off for maintenance.
Boldrochhi Radial Vane Control

43. FD Fan Flow Control Issue in KSA
Example 3
Power Plant in KSA
Benefits of Howden ILD Retrofit
All operational duties achievable.
No change required to actuator.
No change required to DCS operation.
All serviceable parts external to air flow.
Inlet Vane Control

44. FD Fan Flow Control Issue in KSA
Example 3
Power Plant in KSA
To meet our client’s requirements, Howden, along with our local partners in Saudi Arabia, provided the following services:
Site Investigation Work.
Design of all required parts.
Manufacture and Supply of all required parts.
UK based project management of supply scope.
Installation planning.
Removal of existing equipment.
Installation of new Howden equipment.
Post installation commissioning and hand over.
Site supervision and local project management from our UK team on site.
Local skilled site labour.
Scaffolding services.
Lifting equipment

45. FD Fan Flow Control Issue in KSA
Example 3
Power Plant in KSA
Before installation of Howden designed flow control
After installation of Howden designed flow control

46. FD Fan Flow Control Issue in KSA
Example 3
Power Plant in KSA
Outcome
1st boiler FD fans have been successfully retrofitted and been in satisfactory operation since Q
2nd and 3rd boiler FD fans have been successfully retrofitted and been in satisfactory operation since Q

47. Defining the Value
By energy savings

48. Current Non-Howden Fan Proposed New Howden Fan
Defining the Value
By Energy Savings
Howden FD Fan Vs Non Howden FD Fan
Based on $ 0.11 kWh
Current Non-Howden Fan
Proposed New Howden Fan
Savings/Year
Abs. Power (kW)
Cost/Year ($) kW $
PEAK
942
907711
Rated
1016
979018
MCR
802
772807
75%
583
561779
50%
505
486618
25%
477
459637

49. Current Non-Howden Fan Proposed New Howden Fan
Defining the Value
By Energy Savings
Howden FD Fan Vs Non Howden FD Fan
Based on $ 0.11 kWh
Current Non-Howden Fan
Proposed New Howden Fan
Savings/Year
Abs. Power (kW)
Cost/Year ($) kW $
PEAK
942
907711
808
778589
Rated
1016
979018
860
828696
MCR
802
772807
625
602250
75%
583
561779
412
397003
50%
505
486618
335
322806
25%
477
459637
290
279444

50. Current Non-Howden Fan Proposed New Howden Fan
Defining the Value
By Energy Savings
Howden FD Fan Vs Non Howden FD Fan
Based on $ 0.11 kWh
Current Non-Howden Fan
Proposed New Howden Fan
Savings/Year
Abs. Power (kW)
Cost/Year ($) kW $
PEAK
942
907711
808
778589
134
129122
Rated
1016
979018
860
828696
156
150322
MCR
802
772807
625
602250
177
170557
75%
583
561779
412
397003
171
164776
50%
505
486618
335
322806
170
163812
25%
477
459637
290
279444
187
180193

51. Current Non-Howden Fan Proposed New Howden Fan
Defining the Value
By Energy Savings
Howden FD Fan Vs Non Howden FD Fan
Based on $ 0.11 kWh
Current Non-Howden Fan
Proposed New Howden Fan
Savings/Year
Abs. Power (kW)
Cost/Year ($) kW $
PEAK
942
907711
808
778589
134
129122
Rated
1016
979018
860
828696
156
150322
MCR
802
772807
625
602250
177
170557
75%
583
561779
412
397003
171
164776
50%
505
486618
335
322806
170
163812
25%
477
459637
290
279444
187
180193
MCR Yearly Savings per fan = $ 169,835 per fan

52. Defining the Value
By costs

53. Defining The Value By Cost
By Costs
Defining The Value By Cost
SAR
GBP
USD
Selling Price of Electricity
0.12 SAR / kW / hr
0.025 GBP / kW hr
0.032 USD / kW hr

54. Defining The Value By Cost
By Costs
Defining The Value By Cost
SAR
GBP
USD
Selling Price of Electricity
0.12 SAR / kW / hr
0.025 GBP / kW hr
0.032 USD / kW hr
Cost of 1 boiler outage/day = 600,000 kW x 24 hr
1,728,000 SAR / day
360,000 GBP / day
460,800 USD / day

55. Defining The Value By Cost
By Costs
Defining The Value By Cost
SAR
GBP
USD
Selling Price of Electricity
0.12 SAR / kW / hr
0.025 GBP / kW hr
0.032 USD / kW hr
Cost of 1 boiler outage/day = 600,000 kW x 24 hr
1,728,000 SAR / day
360,000 GBP / day
460,800 USD / day
Material cost/failure
16,800 SAR
£ 3,500 / fan
$ 4,480
Labour costs
24,000 SAR
£ 5,000 / day
$ 6,400

56. Defining The Value By Cost
By Costs
Defining The Value By Cost
SAR
GBP
USD
Selling Price of Electricity
0.12 SAR / kW / hr
0.025 GBP / kW hr
0.032 USD / kW hr
Cost of 1 boiler outage/day = 600,000 kW x 24 hr
1,728,000 SAR / day
360,000 GBP / day
460,800 USD / day
Material cost/failure
16,800 SAR
£ 3,500 / fan
$ 4,480
Labour costs
24,000 SAR
£ 5,000 / day
$ 6,400
Duration of failure repair
3 days
Total energy costs x Duration
5,184,000 SAR
£ 1,080,000
$ 1,382,400
Total labour costs x Duration
72,000 SAR
£ 15,000
$ 19,200

57. Defining The Value By Cost
By Costs
Defining The Value By Cost
SAR
GBP
USD
Selling Price of Electricity
0.12 SAR / kW / hr
0.025 GBP / kW hr
0.032 USD / kW hr
Cost of 1 boiler outage/day = 600,000 kW x 24 hr
1,728,000 SAR / day
360,000 GBP / day
460,800 USD / day
Material cost/failure
16,800 SAR
£ 3,500 / fan
$ 4,480
Labour costs
24,000 SAR
£ 5,000 / day
$ 6,400
Duration of failure repair
3 days
Total energy costs x Duration
5,184,000 SAR
£ 1,080,000
$ 1,382,400
Total labour costs x Duration
72,000 SAR
£ 15,000
$ 19,200
Max potential costs/failure
5,272,800 SAR
£ 1,098,500
$ 1,406,080

58. Defining The Value By Cost
By Costs
Defining The Value By Cost
If cost of 1 boiler outage = 5,272,800 SAR (£ 1,098,500)
Assuming 1 unplanned outage, on 1 boiler, every 2 years:

59. Defining The Value By Cost
By Costs
Defining The Value By Cost
If cost of 1 boiler outage = 5,272,800 SAR (£ 1,098,500)
Assuming 1 unplanned outage, on 1 boiler, every 2 years:
Cost over 1 years of managing problem = (5,272,800 / 2) = 2,636,400 SAR (£ 549,250)
Cost over 10 years of managing problem = 26,364,000 SAR (£ 5,492,500)
Cost over 20 years of managing problem = 52,728,000 SAR (£ 10,985,000)

60. Defining The Value By Cost
By Costs
Defining The Value By Cost
If cost of 1 boiler outage = 5,272,800 SAR (£ 1,098,500)
Assuming 1 unplanned outage, on 1 boiler, every 2 years:
Cost over 1 years of managing problem = (5,272,800 / 2) = 2,636,400 SAR (£ 549,250)
Cost over 10 years of managing problem = 26,364,000 SAR (£ 5,492,500)
Cost over 20 years of managing problem = 52,728,000 SAR (£ 10,985,000)
If an average retrofit of boiler fan flow controls (FD or ID) costs £ 600,000 GBP
(N.B. Retrofit price dependant on project scope)

61. Defining The Value By Cost
By Costs
Defining The Value By Cost
If cost of 1 boiler outage = 5,272,800 SAR (£ 1,098,500)
Assuming 1 unplanned outage, on 1 boiler, every 2 years:
Cost over 1 years of managing problem = (5,272,800 / 2) = 2,636,400 SAR (£ 549,250)
Cost over 10 years of managing problem = 26,364,000 SAR (£ 5,492,500)
Cost over 20 years of managing problem = 52,728,000 SAR (£ 10,985,000)
If an average retrofit of boiler fan flow controls (FD or ID) costs £ 600,000 GBP
(N.B. Retrofit price dependant on project scope)
Then payback on typical Howden retrofit = 1.1 Years.

62. Any Questions?

63. Thank you