Boilers final presentation water tube boiler.pptx

A Case study of Water Tube boiler installed at a fertilizer factory

1. CONSTRUCTION & WORKING PRESENTED BY: Muhammad Ibrahim PRESENTED TO: MR. Tashbih ul Hassan Fauji Fertilizers Company Limited (FFCL) Goth Machhi, Sadiqabad CASE STUDY OF BOILER B - 601

2. 1 INTRODUCTION AND MAIN FEATURES 6 SUPERHEATER COILS 2 GAS DUCT AND BOILER ENCLOSURE 7 STEAM DRUM 3 DUCT BURNERS AND FIRING SYSTEM 8 DE-SUPERHEATER 4 ECONOMIZER COILS 9 MECHANICAL PROBELMS 5 EVAPORATOR COILS TABLE OF CONTENTS

3. INTRODUCTION AND MAIN FEATURES 03/10 CAPACITY: 55TONS PER HOUR STEAM PRESSURE: 39 KG/CM^2 STEAM TEMPERATURE: 385oC TYPE: FORCED CIRCULATION WATER TUBE FUEL GAS: TURBINE EXHAUST GASES PLUS AUXILIARY FIRING MANUFACTURER: FOSTER WHEELER USA . 03/10 A simple convection duct boiler producing HS Steam and recovering waste heat of two gas turbines TG-701. AVERY HEAVY STRUCTURE HAS BEEN ERECTED TO SUPPORT THE ENCLOSURE.

4. BURNERS, DUCT DAMPERS ARE INSTALLED IN THE DUCT BEFORE THE BOILER SECTION STARTS THE BOILER DUCT ALSO HOUSES THE BOILER SECTION THAT INCLUDES SUPERHEATER, EVAPORATOR AND ECONOMIZER COILS 01 BOILER GAS DUCT CONSISTS AN OUTER CARBON STEEL SHELL (1/4” Thk.), OUTER COW WOOL INSULATION LAYER (5” Thk.) SS-304 COVER PLATE (1/8” Thk.) THE COVER PLATE IS INSTALLED USING SS-304 ANCHORS(ø1/2”) WHICH ARE WELDED TO THE OUTER SHELL. EXPANSION LAP HAS BEEN PROVIDED BETWEEN EACH PLATE GAS DUCT AND BOILER ENCLOSURE 02 03

5. Acts as an Insert blind to block lines when flow not required GAS TRANSFER DUCT 04/10 Duct Manholes Expansion joint with the duct Made of a flexible material. Accomodates thermal movements Observation Port Made of Tempered Glass, usually BoroSilicate To check if the burners are visible and to overview flame Blanking Plate Assist in the access inside duct to inspect, clean and repair

6. DAMPERS THE DAMPER BLADES REGULATE THE FLOW OF THE EXHAUST GASES TO BOILER OR AWAY FROM THE BOILER. Damper Blades and Shaft --- SS-304 Damper Fins --- SS-316 06/10 Duct Dampers Boiler by-pass Dampers 01 02 03 Shaft is hollow with stubs at both ends . Both are fastened together with cotter pins made of SS-316. The Damper Shaft at the ends is supported by Plummer Block Bearings

7. WORKING OF DUCT DAMPERS 03/10 BOTTOM DAMPER IS POWERED BY A LIMITORQUE OPERATOR MOTOR DAMPERS OPERATE WITH PRE-ADJUSTED BLADE TRAVEL CONTROLLED BY LIMIT SWITCHES. UPPER TWO BLADES CONNECTED WITH LINK OPERATE WITH LOWER DAMPER. THE DAMPERS SEAL AGAINST EACH OTHER (USING A THIN FLEXIBLE DAMPER SEALING STRIP) AND AGAINST DUCT AFTER THEY ARE CLOSED .

8. There are four vertical while one horizontal pilot burner. The burners utilize natural gas for combustion. Vertical and Horizontal burners are made up of SS-304 pipe with holes for Natural Gas outlet Vertical Burners enter the duct from top thru ø2” Gas inlet pipe The Burners are sealed with the duct by Air seals with slightly higher pressure than the one present in the duct. Runner Pipe (Guide Pin) hangs freely inside the support DUCT BURNERS AND FIRING SYSTEMS THE PILOT BURNER AND SEALING SYSTEM RUNNER PIPE END SUPPORT

9. BOILER SECTIONS 07/10 BFW enters the duct through Economizer Coild and leaves as Superheated Steam thru Superheater Coils ECONOMIZER COILS Finned tube coils situated in the upper portion of the duct for recovering waste heat from the flue gases before they leave the boiler Raises BFW temp. from 110oC TO 130oC r Consists of ø2” finned Carbon Steel tubes connected at their ends to a ø6” inlet and outlet headers. No. of rows: 16 No. of Tubes: 24 Total tubes: 384 Total Heating Area: 6061 m2 EVAPORATOR COILS Three sections Top, Middle and Lower. Two independent inlets and two outlets for each section In evaporator coils max. heat transfer takes place and partial evaporation of water takes place. Outlet enters steam drum No. of rows: 16 No. of tubes: 24 Total number of tubes: 384 tubes Total heating area: 6061 m2 SUPERHEATER COILS Hot combustion products first of all come in contact with the superheater coils. The saturated steam at 250o gets maximum of the heat and is super-heated to HS at 400oc Superheater consists of 3 rows of 24 tubes each (total tubes = 72 ea). Lowest row is made of p-1 material (alloy) while upper two rows are of carbon steel ø2” finned tubes are connected at inlet end to ø10” sch. 80 cs pipe header while the outlet header is of ø10” sch. 80 p-1 pipe.

10. EVAPORATOR COILS CONSTRUCTION 10/10 Lower and bottom sections comprise of 4 rows of 24 tubes each (total tubes = 96 ea) T op section comprise of 10 rows of 24 tubes each (total tubes = 240 ea) E vaporator consists of ø2” finned carbon steel tubes are connected at their ends to ø8”sch. 80 carbon steel pipe headers T he tubes are joined together at the ends with each other using 180o bends T he Tubes Are Supported At Three Location With The Duct As Shown In The Figure With A Tube Sheet

11. TUBES PIPINGS & FITTINGS 09/10

12. STEAM DRUM The water from the economizer enters the steam drum thru a dia. 6” perforated pipe, which supplies water along the length of the boiler. Chemical feed line and blow down lines also enter the drum on the same side Pre-heated BFW leaves the drum at it bottom thru two outlets and enters in Evaporator. Water enters steam drum from its sides thru a series of cyclone separators which separates water and steam The separated steam leaves the drum towards superheater from drum top after screening thru demister pads ( Stack of 10 to 12 meshes) The only steam drum 10 feet cylindrical length 5 feet diameter Astm A-516 gr. 70 (carbon steel) BFW inlet line is of ø6”, bottom outlets of ø16” each while saturated steam outlet pipe is of ø10”, all of carbon steel & sch. 80 Nine cyclone separators in two rows for separating water & steam Manholes of ø16” on both ends Two psv’s and a glg for level monitoring are also mounted on the steam drum Construction Working

13. Quickly releases steam from the drumto avoid over pressurization and relieve excess pressure PRESSURE SEAL VALVE(PSV) VENTS Releasing air and dissolved gases during start up to prevent pressure buildup DOUBLE SET GLASS LEVEL GAGE Boiler water gauge glasses let boiler operators visually determine the correct water level within the boiler. D ouble set gauges are used for higher pressures and temperatures.

14. TOP-CUT VIEW X-SECTION STEAM DRUM Construction

15. DE-SUPERHEATER Steam discharge from the superheater is at a higher temperature then required, so boiler feed water is sprayed into it to lower its temperature to bring it to required temperature. Consists of a spray nozzle which spray BFW in steam in mist form. Water quantity sprayed depends on the temperature reading at the inlet to superheater, which is governed by a control valve TIC-153

16. PROBLEM REMEDY Leakage thru Cover Plate inside the Duct Proper and Careful Tack welding Burner’s Guide Pin Hole Crack Due to thrust, Repair the cracks Swelling, Shrinkage Closing/Opening of Automatic Feedwater Inlet Valve Installation Mistakes Proper tightening of bolts Total alignment Sufficient lubrication MECHANICAL PROBLEMS Water tube boiler doesn’t require frequent maintenance but is one of the integral backbones of a plant Most of the mechanical problems in a boiler are addressed either by shut down of the boiler or complete turn around of the plant

17. ANY QUESTIONS PLEASE