Heat recovery – efficiency at any price? - COBRAS 2015

Heat recovery – efficiency at any price?Sebastian Brechtel

Product & Strategy Manager

© Outotec – All rights reserved

Agenda

• Efficiency – General terms• Automotive fuel consumption – „Clean diesel“• Thermal efficiency in acid plants• Financial efficiency - ROI• Facing real life• Take care of your cash cows• HEROS heat recovery system design• Getting digital support

05/01/20232


Efficiency – General terms

05/01/20233

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Removal or conversion efficiency

Operational efficiency

Energy efficiency


Efficiency – Automotive fuel consumption

05/01/20234

Standard operation

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCJj4krHwxMgCFUk5FAod-NEKtg&url=https://commons.wikimedia.org/wiki/File:Efficiency_diagram_by_Zureks.svg&bvm=bv.105039540,d.d24&psig=AFQjCNHFE0OktX46RyNU5GsTCnGSPxJZsw&ust=1445012273632486


05/01/20235

Standard operation




05/01/20236

loss

Best operation

Standard operation



05/01/20237

loss

Standard operation

Best operation




05/01/20238

loss

Standard operation

Best operation

Too small particle filter


DEADLOCK



Thermal efficiency – Waste heat recovery in sulfuric acid plants (sulfur burner)

05/01/20239

SulphurMelting1% 34%

10%IntermediateHeat Exchanger

EvaporatorEconomizer

Final Absorber

Acid Coolers

Tail Gas3%

11%3%

Sulphur98%

ElectricEnergy2%

Blower

DryingTower

Air

Acid Coolers

6%

23% 9%1%

Steam57.5%

Acid Cooling 39%

IntermediateAbsorber

Waste HeatBoiler

ConverterTray No.1

ConverterTray No.2

ConverterTray No.3

ConverterTray No.4

SulphurCombustionFurnace

ProductionAcid0.5%

SteamSuperheater


Thermal efficiency – Waste heat recovery in sulfuric acid plants (sulfur burner)

05/01/202310

SulphurMelting1% 34%

10%IntermediateHeat Exchanger

EvaporatorEconomizer

Final Absorber

Acid Coolers

Tail Gas3%

11%3%

Sulphur98%

ElectricEnergy2%

Blower

DryingTower

Air

Acid Coolers

6%

23% 9%1%

Steam57.5%

Acid Cooling 39%

IntermediateAbsorber

Waste HeatBoiler

ConverterTray No.1

ConverterTray No.2

ConverterTray No.3

ConverterTray No.4

SulphurCombustionFurnace

ProductionAcid0.5%

SteamSuperheater


05/01/202311

Financial efficiency – Return on Investment (ROI)


05/01/202312

?




05/01/202313

Design basis for a financial efficiency calculation

Plant capacity 4500 mtpd H2SO4 (as 100wt%)

Plant location Europe

Plant type Sulphur burning, 3+1

Utility concept “Over the fence” – purchase of electricity, cooling water, demin water and LP steam. Sale of HP and LP steam.

Financial concept Plant cost fully financed by a commercial loan: interest rate 6%, depreciation based on a 20 year period.


ROI – HEROS heat recovery system

05/01/202314

0 0.5 1 1.5 2 2.5 3 3.5 40

0.2

0.4

0.6

0.8

1

1.2

1.4

HEROS

Operational years

Cum

uala

tive

RO

I

$$


ROI - SAP and HEROS™

05/01/202315

0 2 4 6 8 10 12 140

0.20.40.60.8

11.21.4

SAPHEROS

Operational years

Cum

uala

tive

RO

I

$$

$$


Facing real live – Failure scenarios

05/01/202316

Heat recovery (HR) failure scenarios

Short term failure Long term failure

Failure mode Acid pump failure Boiler leakage with weak acid scenario

HR shutdown duration 3 days 3 months

Additional cost[% of initial investment]

3% 20%

$$

$$


Interdependency of Acid plant & Heat recovery system

05/01/202317

loss loss

One way option

Twoway option


05/01/202318

lossloss

Plant down time & production

loss

Fall back to standard operation

One way option

Twoway option

Interdependency of Acid plant & Heat recovery system

Shut down of heat recovery system


ROI - Heat recovery system (failure)

05/01/202319

0 0.5 1 1.5 2 2.5 3 3.5 40

0.20.40.60.8

11.21.4

HR short term failureHR long term failure

Operational years

Cum

uala

tive

RO

I

$$


ROI - Heat recovery system (failure)

05/01/202320

0 0.5 1 1.5 2 2.5 3 3.5 40

0.20.40.60.8

11.21.4

HR short term failureHR long term failure

Operational years

Cum

uala

tive

RO

I

$$??


ROI - Sulphuric acid plant (failure)

05/01/202321

0 2 4 6 8 10 12 140

0.20.40.60.8

11.21.4

HR short term failure

HR long term failure

Operational years

Cum

uala

tive

RO

I

$$


ROI - Sulphuric acid plant (failure)

05/01/202322

0 2 4 6 8 10 12 140

0.20.40.60.8

11.21.4

HR short term failure

HR long term failure

Operational years

Cum

uala

tive

RO

I

DEADLOCK

?


HEROS design aspect: Plant Availability

05/01/202323

AdvantageAcid and HP steam production guaranteed

even if HEROS ís not in operation.

Features

Separation of hot acid circuit from system possible

IAT design for 100 % capacity

Target

Failure of hot circuit must not lead to plant shutdown


HEROS design aspect: Safety precaution 1

05/01/202324

AdvantageWide operational window & minimized

corrosion under off-set conditions

Feature

Material selection: stainless steel & acid resistant bricklining (indicated in red)

Target

Limit hazard potential


HEROS design aspect: Safety precaution 2

05/01/202325

AdvantageMinimized corrosion in case of

heat exchanger failure and emergency stop

Features

Heat exchanger outside of acid tank

Fast isolation of acid and water circuit

Target

Limit hazard potential


Getting digital support

• The PORS (Plant Operability Reliability and Safety) system is a virtual process expert - it is our online know-how at plant site

• Analysis of plant operation for potentially hazardous situations

• Guidance and support for plant operators

Plant Operability Reliability and Safety System

05/01/202326

PORS

Operational Data

Process know-how

Awareness of key

operational trend / upset


05/01/202327

PORS system – virtual process expert

Benefits

Value proposition

Improved process safety and plant availability

Features

Operator support and guidance

Process know-how delivered to site in black box “traffic light” system

Permanent systemic process monitoring and analysis of plant status

Risk mitigation - early detection of developing hazards and reduction of response time to upset conditions

Improved awareness of operators for plant mal-operation

Improved plant availability


05/01/202328

Risk mitigations for heat recovery systems

HEROS™ feature

Availability Flow Sheet Fundamental principle is that HR plant failure will not lead to SAP plant shutdown. The hot acid circuit is completely separated from rest of the acid plant. Intermediate absorption tower is designed for complete SO3 absorption at 100% plant load.

✔

Availability Material of Construction

All vessels are acid-brick lined to minimize corrosion. Use of Alloy 3033, which allows for wide operational window where no brick lining is possible ✔

Safety Flow SheetMaterial of ConstructionAutomation

In fail-safe mode, automatic draining of hot acid by gravity into brick lined equipment, reducing corrosion to minimum levels. ✔

Operability Support tools PORS system for additional high level trending/critical process information requiring operator action to safeguard operating plant integrity. Operator training simulator as optional training measure.

✔


Thank you for your attention ...

Engineering

Heat recovery – efficiency at any price? - COBRAS 2015