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Consultancy. Project Delivery. Innovation. Case Study: Blast Furnace Gas Distribution Dynamic Simulation models distribution of blast gas across a steel mill and optimises modifications Client: Multinational Steel Company

Case Study: Blast Furnace Gas Distribution

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Page 1: Case Study: Blast Furnace Gas Distribution

Consultancy.

Project Delivery.

Innovation.

Case Study: Blast Furnace Gas Distribution

Dynamic Simulation models distribution of blast gas across a

steel mill and optimises modifications

Client: Multinational Steel Company

Page 2: Case Study: Blast Furnace Gas Distribution

Who are we?

Process engineering consultancy

Specialising in advanced modelling techniques, to give answers that

are more accurate, reliable and robust

Expertise in HYSYS Dynamics and Dynsim

Decades of process and mechanical engineering experience

Combine cutting edge simulation with real world understanding, to

provide you with solutions that are effective and practical.

Core team of eight engineers, supported by a wide network of

associates.

Extensive simulation experience across a range of industries

Page 2

Page 3: Case Study: Blast Furnace Gas Distribution

Project Background

Proposed new power plant will consume large amounts of blast gas

Best location for new blast gas connection unclear. Pipes are large >84”,

so high capital cost implications. Potential capital cost savings by using

96” against 108” pipes.

Conventional hydraulic calculations suggest that pressure drop is a

problem due to proposed location but does not take into account

fluctuations in pressure

Low pressure at inlet to power plant risks tripping adjacent power plant

as no provision to cope with low pressure.

Dynamic model expected to converge a better pressure profile and take

into account transient features that affect system pressure

Page 3

Page 4: Case Study: Blast Furnace Gas Distribution

Proposed Tie Points

Page 4

Straight Length for

metering section

Location of New

Power Plant

Page 5: Case Study: Blast Furnace Gas Distribution

Dynamic Simulation Scope

Blast Furnace Outlet

Blast Gas Distribution Main to Consumers

All Consumers (Stoves, Power Plants, Coke Ovens)

Flares and Pressure Control

Gas Holder

Model developed from isometrics, plant survey, trended operating data and

plant trials.

Page 5

Page 6: Case Study: Blast Furnace Gas Distribution

Simulation Model – Hysys Dynamics

Page 6

Gas Holder

Flares 1 & 2

Power Plant

Blast Furnaces

& Stoves

Power Plant

Boilers

Coke Ovens New Power Plant

Page 7: Case Study: Blast Furnace Gas Distribution

Rating of Models

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0

20

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100

120

140

0

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03-May-15 00:00:00 03-May-15 00:57:36 03-May-15 01:55:12 03-May-15 02:52:48 03-May-15 03:50:24Fl

ow

, kN

m3/h

r

Pre

ssu

re,

mb

arg

Continuous changes in system pressure observed from plant data

Dynamic fluctuations in production and consumption built into model

Equipment cycling and controller behaviour reproduced in model

Causes of pressure instability explained by modelling complex co-

incident events.

Page 8: Case Study: Blast Furnace Gas Distribution

Main Modelling Observations

Large pressure fluctuations originate from a combination of rapid

changes in stoves blast gas consumption and furnace gas production

Largest fluctuation originate from older furnace as stoves consumption

erratic and furnace top cone valve oversized or poorly tuned

Gas holder level sensitive to flare flows due to its physical location on

site

Some water seals present high pressure drops suggesting partial

blockage. Gas temperature seen to fall quickly in pipes, resulting in

significant condensation of water vapour.

Page 8

Page 9: Case Study: Blast Furnace Gas Distribution

Design Scenarios

Scenarios only run when model fully rated and accurately reflects plant

operation – including equipment cycling and fluctuations

Client-led scenario definition involving all team members to ensure that

scenarios are relevant and prioritised

Proposed tie-in points examined with a variety of flow conditions

reflecting current and future operating states

Looked at the impact of a sudden trip on the system and amount of

recovery time available to operator

Examined commissioning a larger inlet line to Gas Holder to dampen

fluctuations and improve trip recovery time

Page 9

Page 10: Case Study: Blast Furnace Gas Distribution

Conclusion

The main purpose of the study was to examine best location for new

pipe tie ins, however, other benefits were realised when the model was

available

Concluded that the proposed tie in locations are not feasible at the

maximum design rates without making the following plant changes:

1) Gas train modifications to adjacent power plant to cope with lower

inlet pressures

2) Stabilising blast gas pressures from older furnace

3) Commissioning larger line into the gas holder to dampen pressure

spikes

Page 10

Page 11: Case Study: Blast Furnace Gas Distribution

Summary

Dynamic Model demonstrated that a blast gas distribution system could

be modelled with sufficient detail to allow system characteristics to be

analysed

Static and transient characteristics that were invisible to a static

hydraulic model or through simple analysis of excel data were better

explained

Ease of running scenarios, engaged interest from relevant parties and

helped process understanding

Restarted optimisation projects previously shelved through lack of data

Avoided project failure, by identifying significant shortcomings in

proposed design

Page 11

Page 12: Case Study: Blast Furnace Gas Distribution

Summary

Page 12

Consultancy.

Project Delivery.

Innovation.

Please get in touch to find out how we can help your

business today.

E: [email protected] W: flexprocess.co.uk

T: +44 1454 629 689