debottlenecking metallurgical and sulphur-burning sulphuric acid plants…€¦ · ·...

DEBOTTLENECKING ACID PLANTS

Mahecha-Botero, Cooper, Aksenov, Nikolaisen, 2013

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Andrés Mahecha-Botero, Ph.D., P.Eng., Process Engineer C. Guy Cooper, P. Eng., Director Sulfuric Acid

Igor Aksenov, P.Eng., Process Engineer Kim Nikolaisen, Ph.D., Process Engineer

October 18-22, 2015

Fortaleza, Brasil NORAM Engineering and Constructors Ltd., Vancouver, Canada

DEBOTTLENECKING METALLURGICAL AND SULPHUR-BURNING SULPHURIC ACID

PLANTS: CAPACITY INCREASE AND REDUCTION OF EMISSIONS



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OUTLINE

1.  Introduction

2.  General Acid Plant Debottlenecking Concepts

•  Unplug the arteries •  Performance enhancement •  Energy recovery •  Emissions reductions

3.  Conclusions



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NORAM Engineering

v  Based in Vancouver

v  Founded in 1988

v  Approximately 200 employees

v  Focus on Technology

v  Own BC Research Laboratories

v  Own Axton Fabrication Shop

v  Alliance with Tenova Minerals (formerly Bateman Engineering N.V.)

v  Own NORAM International AB (Sweden)

v  Alliance with Turboscrubber (Osprey/FTL)



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•  Australia •  Belgium •  Brazil •  Canada •  Chile •  China •  Czech Republic •  France •  Finland •  Germany •  India •  Kazakhstan •  Mexico •  Morocco •  Peru •  Portugal •  Russia •  Tunisia •  Venezuela •  UK •  USA

Our Clients ABSA/Fertinal Agrium Agrogen ASARCO Bateman Engineering Bayer BHP Copper Cargill Cellulose du Maroc Chemetics Chevron Climax Molybdenum Codelco Cominco ConocoPhillips Duke Energy DuPont First Chemical Corp Georgia Pacific Huntsman Chemicals Innophos International Paper Kennecott Utah Copper Magma Copper Marsulex Mexicana de Cobre Monsanto Mosaic

Met Mex Penoles Mexichem Newmont Gold Nexen Chemicals

OCP Maroc Paradeep Phosphates Ltd. Pequiven, PDVSA Port Kembla Copper

Phelps Dodge PCS Phosphates Potlatch Corp. Rhodia Qajamarquilla, Refineria de Zinc Quimigal Rubicon Sherritt International Texas Brine Tianji Uniroyal Vale Inco Westlake Weyerhaeser Xstrata



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Stainless Steel Converter with Internal Exchanger

Stainless Steel Converter with Internal Exchanger

RFTM SFTM Preheat Exchanger

RFTM SFTM Gas to Gas Heat Exchanger

Acid Towers

Acid Coolers

Tel: (604) 681-2030 • Fax: (604) 683-9164 • [email protected]

www.noram-eng.com

HPTM Saddle Packing

SMARTTM Acid Distributor



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(2) GENERAL ACID PLANT DEBOTTLENECKING CONCEPTS



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Analogy: Unplug the Arteries

Can we just speed up the flow?



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Reduction of Pressure Drop

Strategies include the use of: •  Low pressure drop Catalyst

•  and larger diameter “dust protection catalyst”

•  Air filter and sulfur filter •  Equipment in parallel



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Reduction of Pressure Drop (Cont’d) Strategies include the use of: •  Radial-Flow Gas Heat Exchangers



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Reduction of Pressure Drop (Cont’d) Strategies include the use of: •  Radial-Flow Gas Heat Exchangers

•  Symmetric heat transfer •  Extended life •  Improved heat transfer •  Compact design •  Low pressure drop •  Metal temperature control •  Reduced condensation & fouling



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In Conventional Cold Exchangers

Sulfate Fouling

Corrosion of Tubes

Upper Tubes

Bottom Tubesheet

Top Tubesheet

Reduction of Pressure Drop (Cont’d) Strategies include the use of: •  Radial-Flow Gas Heat Exchangers with Hot Sweep



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Reduction of Pressure Drop (Cont’d) Strategies include the use of: •  Radial-Flow Gas Heat Exchangers with Hot Sweep

From Bed 3 450°C, 850°F

To IPT 180°C, 350°F

To Hot Exchanger 315°C, 600°F

From IPT 80°C, 175°F

T=260°F =130°C

T=510°F =265°C

Conventional Hot Sweep to Prevent

Sulfate Formation

Hot Sweep



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Simplot Pocatello New Cold Exchanger with Hot Sweep



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Cold Reheat Pressure Drop JR Simplot Company Don Plant

400 SA Cold Reheat Exchanger Pressure Drop

0

5

10

15

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25

30

35

40

45

50

3/20/03 6/28/03 10/6/03 1/14/04 4/23/04 8/1/04 11/9/04 2/17/05 5/28/05 9/5/05

Pres

sure

Dro

p ("

H2O

)



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NORAM Design Much lower number of tubes •  2,800 vs. 5,400

Much lower overall weight •  300,000 lbs vs 500,000 lbs

Shell diameter much smaller •  16 ft vs. 20 ft

Per the salesman: It will do the same heat transfer as the current unit, won’t scale, won’t corrode, and last twice as long!!



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Operation Post Installation

•  The 400 Sulfuric acid plant operates on 2 year turnaround cycles. •  From 2006-2008, no major increase in pressure drop •  Turnaround inspection only. No planned cleaning!

JR Simplot Company Don Plant 400 SA Cold Reheat Exchanger Pressure Drop

0

5

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35

40

45

50

3/24/06 7/2/06 10/10/06 1/18/07 4/28/07 8/6/07 11/14/07 2/22/08 6/1/08 9/9/08

Pres

sure

Dro

p ("

H2O

)



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Reduction of Pressure Drop (Cont’d) Strategies include the use of: •  Low Pressure Drop Acid Tower Packing

NORAM HP™ Saddle Packing

Benefits: •  Low Pressure Drop •  Quality Porcelain Ceramic •  Strong, Few Chips



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Reduction of Pressure Drop (Cont’d) Strategies include the use of: •  Low Pressure Drop Acid Tower Packing.



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Reduction of Pressure Drop (Cont’d) Strategies include the use of: •  Acid distributor above packing

(vs. Buried pipe distributors and spray catcher packing)



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Did we get the arteries unplugged?

Yes → Good

No → Performance enhancement



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Increase of SO2 Gas Strength

•  Increasing the concentration of SO2 in the process gas is the most cost-effective way to increase plant capacity

•  Example: change from 9 to 12 Vol% SO2 = 33% capacity increase change from 11 to 12 Vol% SO2 = 9% capacity increase

•  Allows increased production, without significant changes to the main blower



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Increase of SO2 Gas Strength (Cont’d) Factors that may limit the maximum SO2 concentration include: •  Temperature tolerance of the materials of construction

•  Maximum temperature from outlet of converter bed #1. (1166°F) •  Formation of NOx •  Heat removal capacity

•  Catalyst requirements •  O2 availability (max ~ 12 vol% SO2 sulfur burning) •  Maximum SO2 strength from the smelter



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Still need more Performance Enhancement? (= more acid production)

Strategies include: •  Main blower location: move from “sucker” to “pusher” (ducting

only, not blower) •  Furnace and Waste Heat Boiler Bypass •  Booster fan after the Interpass Absorption Tower

•  Conversion from Double to Single Absorption with Tail gas scrubbing



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NORAM Furnace By-Pass System

FB-1

Furnace Waste Heat Boiler

Conventional Sulfur Burning System

NORAM Furnace By-Pass System

Furnace Waste Heat Boiler

To Converter 10.75%SO2

420°C (790°F)

To Converter 10.75%SO2

420°C (790°F)

10.75%SO2

12.98%SO2

100% 96.8%

82.9% 77.0%

3.2%

Hot Jug Valve

Steam 600 psig

254°C (490°F)

Steam 600 psig

254°C (490°F) 406°C

(763°F)

396°C (745°F)

1093°C (2000°F)

1260°C (2300°F)

Furnace By-pass

Valve

Cold Jug Valve

(Damper)

Air 150°C (300°F)

Sulfur 135°C (275°F)

5.9%

17.1% 23.0%

Air 150°C (300°F)

Sulfur 135°C (275°F)

469°C (877°F)

1093°C (2000°F)



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Energy Improvements and Equipment Upgrades

Strategies include: •  Main blower location relative to Drying Tower:

•  “pusher” max steam production due to more acid produced •  “sucker” max steam per unit of acid produced

•  Dew point analyzer

•  Rotating equipment upgrades

•  Blower motor VFD •  Steam turbine upgrades (steam conditions, jets, gear box, impeller, all new)



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Steam System Improvements

Strategies include:

•  Recovery of heat from hot sulfuric acid:

•  Preheating boiler feed water •  Production of intermediate pressure steam

•  Heat recovery from boiler blowdown systems

•  Replacement of SO3 coolers with steam equipment



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Reduction of Emissions of Sulfur Dioxide

Review: • Loading of the catalytic converter • Catalyst activity, catalyst type, pressure effect on kinetics • Design and mechanical conditions of catalytic converter and gas

exchangers (gas bypass) • Dedicated final tower pump tank to eliminate SO2 stripping in

Final Absorption Tower



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Reduction of Emissions of SO3 and H2SO4:

Review: • Design and mechanical conditions of the final absorption tower,

incl. acid distributor, tower packing, acid irrigation rates • Operating conditions of the final absorption tower • Gas bypassing



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Reduction of Sulfuric Acid Mist or Sprays

Review: • Design and sizing of the mist eliminators • Mechanical conditions of the mist eliminators • Add candles or use longer candles if extra space. Or candle-in-

candle • TurboScrubber system



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Conclusions Debottlenecking

Efficiency •  Energy recovery and equipment design

Emission Reduction •  Catalyst •  Acid tower design •  Gas bypassing •  SO2 Tail gas scrubbing

•  “Unplug arteries” •  Reduce pressure drop (catalyst, gas-exchangers, packing, mist eliminators) •  Increase heat exchanger capacity

•  “Performance enhancement” •  Increase SO2 gas strength •  Furnace/WHB Bypass • “Pusher” vs. “sucker” •  Booster fan



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THANK YOU!

debottlenecking metallurgical and sulphur-burning sulphuric acid plants…€¦ · ·...

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