DEBOTTLENECKING METALLURGICAL AND SULPHUR-BURNING SULPHURIC ACID PLANTS: CAPACITY INCREASE AND REDUCTION OF EMISSIONS

DEBOTTLENECKING ACID PLANTS

Mahecha-Botero, Cooper, Aksenov, Nikolaisen, 2013 1

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, 2015Fortaleza, Brasil

NORAM Engineering and Constructors Ltd., Vancouver, Canada

DEBOTTLENECKING METALLURGICAL AND SULPHUR-BURNING SULPHURIC ACID PLANTS: CAPACITY INCREASE

AND REDUCTION OF EMISSIONS



OUTLINE

1. Introduction

2. General Acid Plant Debottlenecking Concepts

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

3. Conclusions



NORAM Engineering

Based in Vancouver

Founded in 1988

Approximately 200 employees

Focus on Technology

Own BC Research Laboratories

Own Axton Fabrication Shop

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

Own NORAM International AB (Sweden)

Alliance with Turboscrubber (Osprey/FTL)



• Australia

• Belgium

• Brazil

• Canada

• Chile

• China

• Czech Republic

• France

• Finland

• Germany

• India

• Kazakhstan

• Mexico

• Morocco

• Peru

• Portugal

• Russia

• Tunisia

• Venezuela

• UK

• USA

Our ClientsABSA/FertinalAgriumAgrogenASARCO Bateman EngineeringBayerBHP CopperCargillCellulose du MarocChemeticsChevronClimax MolybdenumCodelcoComincoConocoPhillipsDuke EnergyDuPontFirst Chemical CorpGeorgia PacificHuntsman ChemicalsInnophos International PaperKennecott Utah CopperMagma CopperMarsulexMexicana de CobreMonsantoMosaic

Met Mex Penoles

Mexichem

Newmont Gold

Nexen Chemicals

OCP Maroc

Paradeep Phosphates Ltd.

Pequiven, PDVSA

Port Kembla Copper

Phelps Dodge

PCS PhosphatesPotlatch Corp.RhodiaQajamarquilla, Refineria de ZincQuimigalRubiconSherritt InternationalTexas BrineTianjiUniroyalVale IncoWestlakeWeyerhaeserXstrata


Mahecha-Botero, Cooper, Aksenov, Nikolaisen, 2013 5 5

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



(2) GENERAL ACID PLANT DEBOTTLENECKING CONCEPTS



Analogy:Unplug the Arteries

Can we just speed up the flow?



Reduction of Pressure Drop

Strategies include the use of:

• Low pressure drop Catalyst • and larger diameter “dust protection catalyst”

• Air f i l ter and sulfur f i l ter

• Equipment in parallel



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



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

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



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



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

From Bed 3450°C, 850°F

To IPT180°C, 350°F

To Hot Exchanger315°C, 600°F

From IPT80°C, 175°F

T=260°F =130°C

T=510°F =265°C

Conventional Hot Sweep to Prevent Sulfate

Formation

Hot Sweep



Simplot Pocatello New Cold Exchanger with Hot Sweep



Cold Reheat Pressure Drop

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

0

5

10

15

20

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

)



NORAM DesignMuch 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!!



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

10

15

20

25

30

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

)



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



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



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

(vs. Buried pipe distr ibutors and spray catcher packing)



Did we get the arteries unplugged?

Yes → Good

No → Performance enhancement



Increase of SO2 Gas Strength

• Increasing the concentration of SO 2 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 signif icant changes to the main blower



Increase of SO2 Gas Strength (Cont’d)Factors that may l imit the maximum SO 2 concentration include:

• Temperature tolerance of the materials of construction

• Maximum temperature from outlet of converter bed #1. (1166°F)

• Formation of NO x

• Heat removal capacity

• Catalyst requirements

• O2 availabil i ty (max ~ 12 vol% SO 2 sulfur burning)

• Maximum SO 2 strength from the smelter



Stil l 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



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 Converter10.75%SO2

420°C(790°F)

To Converter10.75%SO2

420°C(790°F)

10.75%SO2

12.98%SO2

100% 96.8%

82.9% 77.0%

3.2%

Hot JugValve

Steam600 psig

254°C(490°F)

Steam600 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)



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)



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 SO 3 coolers with steam equipment



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 el iminate SO 2 str ipping in Final Absorption Tower



Reduction of Emissions of SO 3 and H2SO4:

Review:

• Design and mechanical conditions of the final absorption tower, incl. acid distr ibutor, tower packing, acid irr igation rates

• Operating conditions of the final absorption tower

• Gas bypassing



Reduction of Sulfuric Acid Mist or Sprays

Review:

• Design and sizing of the mist eliminators

• Mechanical conditions of the mist el iminators

• Add candles or use longer candles if extra space. Or candle-in-candle

• TurboScrubber system



ConclusionsDebottlenecking

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 SO 2 gas strength• Furnace/WHB Bypass •“Pusher” vs. “sucker” • Booster fan



THANK YOU!