Thermal Distributive Blast Furnace Gas

Characterisation; a Steelworks Case Study

Tata Port Talbot Steelworks

Daniel Pugh – Ph.D Research Student Cardiff University School of Engineering

Sustainable Thermal Energy Management in the Process Industries International Conference (SusTEM2011)

Sampling Objectives

Dynamic Compositional Sampling – Compare compositions attained through chromatographic analysis with values attained from steelworks probes. Gravimetric Particulate Loading Evaluation – Determine particulate mass gas contamination through isokinetic analysis. Condensate Characterisation – Evaluate the change in condensate chemistry as gas is distributed around the works.

N2 + O2

1200°C

CxHy + H2O

FexOy C

Fe + C

N2 + CO + CO2 + H2 + H2O

Reduction of Hematite: Fe2O3 + 2C → 2Fe + CO + CO2

Fe2O3 + 3CO → 2Fe + 3CO2

Boudouard Reaction:

2CO ↔ CO2 + C

What is Blast Furnace Gas?

Blast Furnace Gas

2000°C

What is Blast Furnace Gas?

H2

N2

CO2

CO

52

23

23

2

Typical Calorific Value 3-4 MJ·Nm-3

Each furnace can produce over 400 kNm3 per hour

Volumetric

Sampling Location

Google

A

B

B B

C

Coke Ovens

BOS Plant

Service Boilers

Sinter Plant

Power Plant

Blast Furnace 5

Blast Furnace 4

P

S

Flares

B

Gas Holder Approx

1.5km

Cold Rolled

Products

Hot Rolled

Products

Live Site Ring Main: 3 Flow distribution directions A, B, C Over 1.5 km between where gas is produced and sampled

S

- Gas Produced

- Gas Sampled

P

Gas Sampling Apparatus

2. Valve

1. Sample Probe

7. Rotameter

8. Pump

5. Filter Holder

6. Gas Sampling Pump

4. Manometer

3. N2 Purge

3. N2 Purge

Test at multiple points across the pipe diameter, gas samples taken into ‘Gresham’ kit. Use laboratory gas-chromatograph for compositional analysis. Use of pseudo-isokinetic gravimetric technique to calculate particulate loading. Filter mechanism developed.

Filter Development

Emfab Pallflex borosilicate glass micro-fibres

Woven glass cloth and bonded PTFE chosen for favourable hygroscopic properties. Nominal Pore size - 1μm. Sterilised and strengthened.

Gas Chromatograph Results

DATE - TIME

DRY COMPOSITION (% VOL) GAS PROPERTIES

DRY GAS

N2 H2 CO CO2 DENSITY KG/NM3

CV GROSS

MJ/NM3

CV NET MJ/NM3

01/02/11 – 11:45 48.29 2.74 25.67 23.30 1.385 3.592 3.538

01/02/11 – 12:25 46.74 2.62 26.71 23.93 1.391 3.708 3.656

01/02/11 – 13:35 48.34 2.78 25.48 23.41 1.385 3.572 3.518

01/02/11 – 14:14 48.58 2.62 25.57 23.23 1.386 3.564 3.513

01/02/11 – 14:16 48.27 2.71 25.49 23.53 1.387 3.565 3.512

10/02/11 – 11:00 49.64 2.82 25.05 22.49 1.378 3.524 3.469

10/02/11 – 11:40 49.33 2.81 25.28 22.58 1.379 3.551 3.496

10/02/11 – 13:00 49.26 2.83 25.52 22.39 1.378 3.584 3.529

10/02/11 – 13:50 49.97 2.78 25.04 22.21 1.377 3.517 3.462

10/02/11 – 14:45 49.28 2.91 25.59 22.22 1.375 3.603 3.546

16/02/11 – 11:00 53.09 2.24 23.46 21.20 1.376 3.249 3.205

16/02/11 – 12:00 52.87 2.57 26.29 18.26 1.351 3.649 3.599

16/02/11 – 13:25 49.42 2.89 27.00 20.70 1.365 3.778 3.722

16/02/11 – 14:50 53.23 2.39 24.40 19.98 1.365 3.387 3.340

Use of single Calibration Standard with linear response factors H2 – 2.5 %

CO – 23 %

CO2 – 23 %

N2 – 51.5 %

Gas Chromatograph Results

N2 H2 CO CO2

% 48.05 2.69 25.78 23.48

SD 0.739412 0.071972 0.52324 0.276043

N2 H2 CO CO2

% 52.15 2.52 25.28 20.05

SD 1.827683 0.279687 1.639621 1.284925

N2

H2

CO

CO2

N2

H2

CO

CO2

N2

H2

CO

CO2

N2

H2

CO

CO2

01/02/2010 16/02/2010

Particulate Loading Results

AV. WEIGHT BEFORE mg (SD)

AV. WEIGHT AFTER

mg (SD)

AV. CHANGE IN MASS

mg

GAS VOLUME L

PARTICULATE LOADING mg/m3

258.4 (0.1) 258.5 (0.07) + 0.091 540 0.169

264.2 (0.12) 264.3 (0.08) + 0.050 720 0.069

289.1 (0.05) 289.2 (0.05) + 0.167 2160 0.077

291.4 (0.04) 291.6 (0.07) +0.208 2160 0.096

288.1 (0.05) 288.2 (0.05) + 0.133 3600 0.037

297.3 (0.09) 297.9 (0.08) + 0.592 6000 0.099

289.4 (0.05) 289.7 (0.06) + 0.242 4500 0.054

Calibrated, high precision balance resolution: 0.1mg Fluctuations in results obtained, therefore average taken from multiple readings

(Expected up to 50 mg/m3)

Condensate Analysis

Samples taken from each point:

− 20 ml sample for ICP non-filtered - Analyse for Fe, Zn, Ca, Si, S

− 20 ml sample for ICP Filtered using 0.45μm Millipore disposable filter tip

− 25ml sample taken for GC-MS analysis Water Chemistry:

pH, Dissolved Oxygen, Electrical Conductivity, temperature, measured with Hanna H9828 multi-parameter probe

Condensate Trap Locations

A

B

B B

Coke Ovens

BOS Plant

Service Boilers

Sinter Plant

Blast Furnace 5

Blast Furnace 4

P

S

Flares

B

Gas Holder Approx

1.5km

Cold Rolled

Products

1

2

3

4

6

7

8

9

5

10 11

Site Ring Main

Condensate trap locations were sampled around the works

Condensate Results

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Distance (m)

Si Ca S

Flow Directions A B

No

rmal

ised

Co

nce

ntr

atio

n

Conclusions

Compositional analysis yielded favourable values to those obtained from the furnace, allowing for further combustion work into dynamic fuel performance. Particulate loading analysis at the used location yields negligible results, with further analysis suggesting accuracy of results depends on location. Condensate analysis suggests gas appears to be thermally scrubbed of particulate matter, and therefore gas cleanliness a function of distance from the furnace.

Industrial Ramifications

Analysis work used in discussions with industrial partners to further considerations of alternative use for Blast Furnace Gas as a fuel. Explanation given for the agglomeration of matter within the condensate overflow, leading to a possible redesign to avoid maintenance issues.

Acknowledgments

Thanks to: EPSRC

Tata Steel – Chris Williams

Cardiff Catalysts institute - Dr. Karen Wilson, Dr. Tom Davies, and James Hayward

Cardiff University School of Engineering - Gareth Hunt

Thank You – Questions?