Talwandi Sabo Power · PDF fileTender Document For Upgradation Of Dry Ash Conveying System ... Talwandi Sabo Power Plant is a supercritical thermal power ... Fluidizing air system

Talwandi Sabo Power Limited Tender Document For Upgradation Of Dry Ash Conveying System

Techno commercial offers are invited from the competitive bidders for the EPC contract i.e. for System

study, Review, Engineering, Providing solution and implementation of solution which includes

manufacture/Supply, Erection, Testing, Commissioning, Demonstration of performance guarantee for Dry

Ash Conveying system from Boiler/ESP to Ash Silos in 3 units of 660mw each in thermal power plant at

Talwandi Sabo Power Limited, Village Bana Wala, Mansa Punjab.

Introduction:

3X660 MW, Talwandi Sabo Power Plant is a supercritical thermal power plant located in Mansa, Punjab

having its all unit commissioned between 2014 and 2016. For handling ash, dense phase pneumatic

conveying system has been provided by M/s SEPCO through M/s Sino Finn. The system covers the ash

collected in hoppers of economizers, APH and precipitator. Fly ash collected in the hoppers is evacuated

sequentially to fly ash silo by the dense phase pneumatic conveying system. The ash/air ratio is about 30.

The compressed air system for all three units is as one design unit. The instrument compressed air system

and ash handling compressed air system is separate. The function of ash handling compressed air system

is to supply air for fabric filter pulsing, pneumatic valve operations and fly ash conveying. Total 17 nos.

service air compressors of 62 Nm3/min each have been provided with 13 nos. air receiver tanks of 50 m3

each ( 9 for service air , 3 for instrument air and one as buffer), 11 nos. Freeze air drier of 100 Nm3 each

for conveying air and 4 nos. combined air drier of 50 Nm3 each for instrument air.

A. Initial Design information:

1. Coal Analysis: Proximate Analysis (% by weight)

S.No. Description Design Quality (%)

Worst Quality (%)

1 GCV (Kcal/Kg) 3300 3000

2 Ash 41.6 45

3 Volatile Matter 22 21

4 Fixed Carbon 24.5 22

5 Moisture 11.9 15

2 Ash Analysis:

S.No. Ash Analysis Design Quality Worst Quality

1 Deformation Deg. C 1290 1340

2 Hemishere Deg.C 1350 >1400

3 Flow Deg. C 1500 >1400

4 Moisture % 0.14

5 Unburnt carbon % 0.36


6 SiO2 % 54.9 59.6

7 Al2O3 % 25.4 30.75

8 Fe2O3 % 9.3 6.5

9 TiO2 % 1.3 1.75

10 P2O5 % 0.1 0.47

11 K2O % 0.3 0.27

12 CaO % 3.1 0.25

13 MgO % 1.8 0.08

14 Na2O % 0.3 0.15

15 So3 % 2.3 0.03

16 Mn3O4 Undetermined % 0.7 0.15

3. Coal Consumption

Design coal consumption at BMCR: 459.7 TPH

Worst Coal consumption at BMCR: 508.2 TPH

4. Calculated Ash Quantity for each Boiler at BMCR is as follows:

Discharge Design capacity of Boiler calculated Ash

Design Coal (B-MCR) TPH

Worst Coal (B-MCR) TPH

Boiler calculated Ash 100 % 195.89 231.98

Bottom Ash 20 % 39.18 46.40

FF+Precipitator fly ash 90 % 176.3 208.78

Eco Fly Ash 5 % 9.79 11.60

APH Fly ash 5 % 9.79 11.60

Total Ash 120 % 235.06 278.37

5. Ash Quantity of Fly ash Hoppers

Discharge Place No. of Hoppers Design Coal (TPH) Worst Coal (TPH)

First Field 2X4=8 141 167

Second Field 2X4=8 28.2 33.4

FF 2X4X3=24 7.2 8.4

Eco 6 9.79 11.6

APH 8 9.79 11.6

6. Bulk Density of Fly ash

Fly ash for volume computation: 800 Kg/m3

Fly ash for strength computation: 1600 Kg/m3


Fly ash for ESP/APH/ECO hopper volume computation: 750 Kg/m3.

7. Hopper capacity:

Fly ash hopper storage capacity is 8 hours. Evacuation time for ash removal from ash hopper is 40 to 100

seconds.

B. Intent of the Content

We are facing ash evacuation problems in dense phase pneumatic conveying system as follows

1. ESP hopper levels not getting maintained above coal flow of 450 TPH.

2. Ash collection is more in the B and C pass hopper as compare to A and D pass and most

of the time hopper levels are high and fields remain discharged in B and C pass.

3. As both fields are discharged ash load on Fabric Filter increases resulting in high hopper

levels of Fabric Filter (FF) and bypassing of FF due to high DP.

4. Ash Conveying line Dome seal air pressure keeps fluctuating and there is a high frequency

of dome seal failures which in turn require frequent stoppages of conveying stream

5. Frequent choking of the conveying lines due to coarse ash are observed resulting in

increased conveying time and high hopper levels

6. High failure of dual disk type vent valves affecting vessel filling.

7. Due to choking in lines, vents and pressure relief valves are used frequently to clear

choking resulting in vent and PRV line erosion and ash leakages.

8. Upon complete filling of the vessels, choking is being observed.

9. Against the design of single conveying, parallel conveying is being done to maintain the

levels resulting in reduction in dome seal and conveying air pressure.

10. Issues in Economizer Ash Hopper and APH Ash Hopper conveying due to frequent

jamming of dual disk type filling valve

To increase the redundancy in the ESP conveying system, 2 more additional lines in each unit &

2 nos. compressors of 90 Nm3/min each were added after system startup but still hopper levels

are not getting maintained at worst coal operations.

Intent of this tender is to carry out detailed system study of dense phase ash conveying system

with existing ESP and FF arrangement, review the existing system, develop solution, discussion

with technical team and implement the solutions for smooth evacuation of ash from Economizer,

APH and ESP & fabric filters hoppers in full load condition. Even in case of outage of ESP fields

and all the ash load going to FF hopper, evacuation should be smooth.


C. Battery limits for the study and implementation of solution

1. Outlet of ESP, FF, ECO and APH hopper to the inlet of silo including hopper outlet MIV 2. Service and instrument compressed air system 3. Air compressors and driers 4. Fluidizing air system 5. Silo and its loading system including Bag house & vent fan at silo top

D. KPIs

1. Agency shall demonstrate the conveying system for 3 months without hopper level indication

getting high at full load operations and with zero choking & leakage in conveying system,

2. FF hopper levels should maintain even on outage of both the ESP fields on full load operation.

E Drawings and Documents

Attached Drawings and Documents are illustrative and agency is required to visit site before submitting

the offer.

1. Drawings

a) GA drawing of Ash Handling Plant

b) Plan arrangement drawing for top floor of fly ash silos

c) Erection drawing of ash conveying equipment

d) Fly ash fluidizing system drawing

e) GA drawing of ash handling compressor house

f) Layout drawing of fly ash piping Unit#1&2

g) Layout drawing of fly ash piping Unit#3

h) System drawing of compressed air piping in Ash handling compressor house

i) Arrangement for compressed air piping for ash conveying in ESP+FF

j) Arrangement of equipment and piping of ash conveying for ECO and APH.

k) ESP additional piping layout drawing

2. Documents

a) Ash conveying system Sizing Calculation

b) Sizing calculation of bag filter at silo top

c) Sizing calculation of transmitter tank

d) Sizing calculation of compressed air piping and bag filter

e) ASH handling plant Design Basis report


GA of Ash handling plant

Plan arrangement drawing for top floor of silo


Erection drawing of ESP conveying equipment


Erection drawing of FF conveying equipment


Fly ash fluidizing system drawing


GA drawing of ash handling compressor


GA drawing of Air Driers

Plan arrangement for equipment & piping of ash conveying for ECO and APH


ESP Additional piping layout drawing



Plan arrangement for equipment and piping for ash conveying of ECO and APH
