Optimising Power Generation Maintenance using Thermal and CFD modelling Warwick Ham Boiler Process Engineering Group Leader Steinmüller Africa,

Transcription

1 Optimising Power Generation Maintenance using Thermal and CFD modelling Warwick Ham Boiler Process Engineering Group Leader Steinmüller Africa, Bilfinger Power Systems South Africa

2 Summary Introduction Failure statistics How to improve availability Using CFD to understand the real causes Record keeping Don t just fix it Change it!

3 Introduction

4 Introduction The Coal Fired Power Generation Cycle Economizer Steam Turbine Superheater/Reheater HP - Pipes Generator Steam Generator Feedwater System Condenser Cooling Tower DeNOx - SCR Coal Feeder Firing Systems Coal/Oil/Gas Heat- Recovery System Mill Air Preheater Ash Silo FD - Fan Precipitator FGD De-Ashing De-Ashing ID - Fan FGD - Fan Stack

5 Failure Statistics The most common types of Failures X Power Station - BTF Mechanism Fatigue Corrosion Fatigue Fly Ash Erosion Falling Object Damage Number of BTFs

6 Failure Statistics Fly Ash Erosion Failure Locations Economiser Reheater Helical Wall Division Wall 18 X Power Station - BTFs per Component Number of BTFs Economiser Division wall Screw wallvertical wall Superheater Superheater 1 Superheater 2 Reheater 3 1Reheater

7 Failure Statistics The most common Fly Ash Erosion Causes Operation outside of design envelope Excessive startups/shutdown High ramp rates Excessively high load Operation outside fuel envelope High Ash High Moisture Low CV Erosion High flue gas velocity

8 Improve Availability How? Design Realistic specifications Operation Procedures Maintenance Adjust maintenance philosophy to actual operating conditions Understand the mechanisms System thinking Detailed CFD investigations

9 Using CFD Understanding Mill Wear Boiler erosion Pressure Parts Non Pressure Parts Manufacturing Quality

10 Using CFD Understanding Mill Wear (Video) Excellent agreement between CFD prediction and actual wear patterns

11 Using CFD Understanding Mill Wear Excellent agreement between CFD prediction and actual wear patterns

12 Using CFD Understanding Mill Wear Improved design

13 Using CFD Understanding Boiler erosion Pressure Parts

14 Using CFD Understanding Boiler Pressure Part Erosion Localisation Erosion Rate

15 Using CFD Understanding Boiler Non Pressure Part Erosion Localised Rate

16 Using CFD Understanding Boiler Non Pressure Part Erosion

17 Using CFD Understanding Maintenance Manufacturing Quality Spherical header

18 Using CFD Understanding Manufacturing Quality Heat treatment Spherical header Heat treatment procedure

19 Record keeping the key Design records Basis Fuel Range Operating mode Lifetime Original design assumptions Modifications Maintenance experience

20 Record keeping the key Operating records Procedures Maintenance records Failure RCA X Power Station - BTFs Root Cause Number of BTFs Poor workmanship Poor operating Design defect Modification defect Ageing Unknown

21 Don t just fix it Change it! Assess original design intent against actual conditions Challenge assumptions Assess operating procedures Assess maintenance trends Understand the causes Develop new design basis

22 Summary Introduction Failure statistics How to improve availability Using CFD to understand the real causes Record keeping Don t just fix it Change it!