the suitability of double absorption and scrubbing ... · pdf filethe suitability of double...

EMISSIONS REDUCTION

Mahecha-Botero, Cooper, Nikolaisen, 20141

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

Kim Nikolaisen, Ph.D., Process Engineer

Mesa RedondaPunta Arenas (53°S)

November 16-20, 2014

NORAM Engineering and Constructors Ltd. Vancouver, Canada

The Suitability of Double Absorption and Scrubbing Technologies to Meet New

Emission Standards

EMISSIONS REDUCTION


NORAM Engineering

Based in Vancouver

Founded in 1988

Approximately 100 employees

Focus on Technology

Own BC Research Laboratories

Own Axton Fabrication Shop

Alliance with Tenova Minerals

Own NORAM International AB (Sweden)

Alliance with Turboscrubber (Osprey/FTL)

Represented by Coppex in Chile

EMISSIONS REDUCTION


• Australia

• Belgium

• Brazil

• Canada

• Chile

• China

• Czech Republic

• France

• Finland

• Germany

• India

• Kazakhstan

• Mexico

• Morocco

• Peru

• Portugal

• Russia

• Tunisia

• Venezuela

• UK

• USA

ClientsABSA/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

Glencore

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

Teck Metals

Texas Brine

Tianji

Uniroyal

Vale Inco

Westlake

Weyerhaeser

Xstrata

EMISSIONS REDUCTION


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

EMISSIONS REDUCTION


Pre-Summary

• Chilean smelters are set to spend large amounts of money to meet new Chilean emission standards

• Evaluate options carefully taking into account: Risk, CAPEX and OPEX.

• Double Absorption is the proven world standard to reduce emissions.

• NORAM has proven effective equipment to use in double absorption

• Look at the use of low pressure drop packing and low pressure drop, reduced fouling gas exchangers to lower operating costs and increase on-stream time

EMISSIONS REDUCTION


OUTLINE

(1) IntroductionNew Chilean Emission StandardsComparison of New Chilean Emission Standards with Those of Other Countries

(2) Double-Absorption TechnologyOverview

Advantages of Upgrading to Double-AbsorptionRequirements to Convert to Double-AbsorptionDesign Considerations to Reduce SO2 EmissionsNew Equipment

EMISSIONS REDUCTION


OUTLINE (Cont’d)

(3) Tail Gas Scrubbing TechnologyOverviewDifferent Scrubbing TechnologiesNew Equipment

(4) Conclusions

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(1) INTRODUCTION

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New Chilean Emission Standards New emission standards require technology upgrades to achieve

higher capture of SO2 and As. Careful selection of technology is required.

The new targets are achievable with existing technologies.

EMISSIONS REDUCTION


SO2

Limit

%

Decrease

in

Emissions

Required

SO2

Limit

%

Decrease

in

Emissions

Required

Date of Start

of

Enforcement

1 Caletones Codelco 1922 2 01560 MTPD &

2390 MTPD128,468 32.7% 88.0% 80,000 38% 47,680 63% 12-Dec-2018

2 Chuquicamata Codelco 1952 3 03 x 2040

MTPD108,214 27.5% 91.0% 96,500 11% 49,700 54% 12-Dec-2018

3 Potrerillos Codelco 1927 1 0 1500 MTPD 65,280 16.6% 83.5% 89,500 None 24,400 63% 12-Dec-2018

4 Altonorte Xtrata 1993 2 12 x 2040

MTPD39,958 10.2% 93.7% - - 24,000 40% 12-Dec-2016

5Hernan Videla

Lira / PaipoteEnami 1952 2 0

280 MTPD &

560 MTPD21,344 5.4% 89.4% 24,500 None 12,880 40% 12-Dec-2018

6 Ventanas Codelco 1965 1 1 1637 MTPD 15,590 4.0% 93.8% 16,500 None 14,650 6% 12-Dec-2016

7 Chagres AngloAmerican 1960 1 1 1885 MTPD 13,944 3.5% 95.7% 13,950 None 14,400 None 12-Dec-2016

392,798 187,710

9 52.2%

New Total Allowable SO2 Emissions

Total Reduction of SO2 Emissions as

Compared to 2010

Capacity of

Acid Plants

Total SO2 Emissions (2010)

Total Potential Plants to Convert to Double Absorption

CHILEAN METALLURGICAL ACID PLANTS SPECIFICALLY MENTIONED IN THE NEW EMISSIONS REDUCTION LEGISLATION

#

# of Double

Absorption

Acid Plants

Total

Number of

Acid Plants

Average

Capture91%

Temporary Limit

for Transition

Period

New Limit for Existing Plants

%

Capture

S

%

contribution

to total

Chilean

smelter

emissions

SO2

Emissions

(2010)

Start-up

dateOwnerPlant

New Chilean Emission Standards

Acid plant target of 600 ppm is less stringent than in most countries. Typical world scale acid plant can easily achieve 250 ppm with double absorption only.

EMISSIONS REDUCTION


Comparison of New Chilean Emission Standards with Other Countries

The limit of SO2 emissions from the stack in North America is: 2 kg of SO2 per metric ton of H2SO4 produced.

For a plant operating with 12% SO2 to bed #1, this corresponds to about 360 ppm stack SO2 concentration and 99.7% capture of SO2.

In practice, typical double-absorption plant emissions in the USA range between 0.5 and 2 kg SO2/MT H2SO4 (corresponding to about 90 to 360 ppm stack SO2 concentration and 99.7 to 99.92% capture of SO2).

70 ppm stack SO2 is achievable with double absorption only.

Emissions of 10 to 50 ppm require tail gas scrubbing.

EMISSIONS REDUCTION


(2) DOUBLE ABSORPTION TECHNOLOGY

EMISSIONS REDUCTION


Overview

Smelter gases contain a long list of chemical species including SO2,SO3, H2SO4, As, Se, F, Cl, Pb, Cd, Cu, Bi, dust, etc. Currently, the smelter gases are processed in a gas cleaning plant followed by a sulphuric acid plant. The smelter acid plant design intent is to:

Reduce emissions of SO2, SO3 and H2SO4 to the environment by 97 to 99.95% (depending on plant design).

Produce commercial sulphuric acid for sale, or for internal use.

The heart of the pollution control system of the metallurgical site is the sulphuric acid plant.

EMISSIONS REDUCTION


EMISSIONS REDUCTION


Single Absorption Acid Plants

Single-absorption sulphuric acidplants were common prior to the1970’s.

Stack emissions in the range of 2000to 10,000 ppm, and SO2 capture ratesof > 97%.

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Typical Single Absorption Gas System

Typical converter has 3 catalyst beds.

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Double Absorption Gas System (3/1 configuration)

New gas equipment: Final acid tower, 4th pass and gas exchangers

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Single Absorption Acid System

Typical acid system has 2 to 3 towers.

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Double Absorption Acid System

New acid equipment: Final acid system

EMISSIONS REDUCTION


Double Absorption Acid Plants

Double-absorption allows for higher SO2 capture by shifting thechemical equilibrium of SO2 oxidation by removing the SO3product.

Converting an existing single-absorption plant into double-absorption can increase the production rate of sulphuric aciddue to increased SO2 capture (by 2 to 10%), and due to theability to increase process gas concentrations (by 10 to 30%).

The benefits of conversion to double absorption are maximizedif the plant upgrade is carried out together with adebottlenecking and capacity increase project.

EMISSIONS REDUCTION


Double Absorption Acid PlantsNew double-absorption acid plants use one of the followingconfigurations:

2/2 Configuration: Usually not used for new designs, since it requires larger heat exchange equipment and higher catalyst volumes.

3/1 Configuration: This has become the standard for modern contact sulphuric acid plants. Conversions of 99.7 to 99.8+% can be achieved (corresponding to about 240 to 360 ppm of SO2 in the stack).

Enhanced Configurations using Cesium Catalyst, Enriched Air or additional conversion stages: Can achieve 99.95% recovery (corresponding to as little as 70 ppm of SO2 in the stack).

EMISSIONS REDUCTION


600 PPM in the Stack?If a double absorption plant cannot meet 600 ppm, it is likely due to:

Gas Leaks in the Division Plates of The Converter: These leaks would reduce the conversion considerably. Not only SO2 is bypassed, but SO3 can affect chemical equilibrium.

Gas Leaks in the Gas Exchangers: Asarco East Helena, Montana, USA. Fixing gas leaks in the cold exchanger reduced emissions 600 ppm to 300 ppm.

Low Catalyst Activity and Catalyst Fouling: Review of catalyst performance is required.

Inadequate Converter Inlet Temperature Control: Control strategy and design of gas dampers to be reviewed.

EMISSIONS REDUCTION


600 PPM in the Stack?

Inadequate Performance of Interpass Tower: Carryover of acid mist or SO3 would reduce converter performance.

Final Acid Pumping Loop not Independent: A separate final acid pumping loop can reduce the emissions of SO2 to the stack by up to 100 ppm without requiring any changes to the converter.

Other issues with plant design, equipment performance and operation.

EMISSIONS REDUCTION


Advantages of Upgrading to Double-Absorption

Capability: can achieve the new emission standards.

Water conservation: Zero losses of water from the plant stack.

No production of byproducts or waste: Other technologies produce a scrubbing waste, which is proportional to the plant rate and inlet concentration of SO2, SO3 and H2SO4.

No consumption of chemicals: Examples of these chemicals are caustic, ammonia, hydrogen peroxide, milk of lime, limestone, etc.

No steam consumption: In contrast, regenerative scrubbing requires a constant feed of steam to regenerate the absorbent chemicals.

EMISSIONS REDUCTION



Produces concentrated H2SO4 for sale

Familiar technology: Commonality of controls and spares.

Proven technology: Lower technical risk of having unplanned shut-downs.

Known technology: Technology is well known to plant engineers and operators. Little training to existing personnel is required.

Simple logistics: No requirement of: new storage tanks for chemicals, logistics and infrastructure to supply and handle new chemicals, effort to handle and dispose of byproducts.

EMISSIONS REDUCTION



Public perception: No visible plume from the stack.

Low operating costs.

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Disadvantages of Double-Absorption

Layout and hydraulic considerations

Initial capital investment

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NORAM Split Flow Gas Exchanger

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New Equipment (cont’d)

Review of Converter Capacity

The SO2 conversion capabilitymust be reviewed under theupgraded conditions. Increasedcatalyst volumes are required toachieve the new emissiontargets.

In many cases, the existingconverter has enough sparevolume to accommodate theadditional catalyst loads. If theconverter is undersized, it canbe modified for the new service.

EMISSIONS REDUCTION


(3) TAIL GAS SCRUBBING

EMISSIONS REDUCTION


Overview

The selection of the scrubbing chemistry depends on:

Potential use for byproducts.

Handling and disposal of byproducts.

Local availability of chemical.

Local price of chemical taking into account delivery and handling.

Familiarity of the plant site with the scrubbing chemical.

Losses of scrubbing chemical due to upstream problems: For regenerative scrubbing: One client in USA spends $0.5 million per year on amine chemicals due to acid mist issues at the inlet.

EMISSIONS REDUCTION


Different Scrubbing Technologies

A number of technologies can be used to contact the process gas with the scrubbing chemical.

Packed Beds: Uses static packing inside a counter-current contacting tower.

Reverse Jets: Uses large liquid flow in contact with the gas in a froth-zone.

Venturis: Use a flow restriction to allow for co-current contact between the liquid and the gas.

EMISSIONS REDUCTION


Different Scrubbing Technologies(cont’d)

Spray Towers: Produces fine liquid droplets in atomization nozzles. They can be co-current or counter-current.

Fluidized-Beds: Gas and liquid are contacted over a moving bed. Gas and liquid are counter-current.

EMISSIONS REDUCTION


New Equipment

New Scrubbing System

New Scrubbing Tower: The tower can be made of steel, FRP, or other materials of construction.

New Scrubber Cooler: A cooler may be required to reject the heat from the process gas.

New Scrubber Pump: Depending on the design of the new scrubbing tower, a new pump-tank may be required.

EMISSIONS REDUCTION


New Equipment (cont’d)

New Scrubbing Ancillaries

New Byproduct Storage Tank

New Scrubbing Chemicals Tank

New Ancillary Pumps: To handle scrubbing and waste liquids.

Review of Stack: Scrubbing systems saturate the process gas with water. For this reason it is sometimes recommended to review the materials of construction of the stack.

EMISSIONS REDUCTION


Fluidized Bed Scrubber Installations (NORAM’s TurboScrubber®)Left: SO2, fine particulate abatement, and heat recovery. Right: SO2

and fine particulate abatement

EMISSIONS REDUCTION


(4) CONCLUSIONS

EMISSIONS REDUCTION


Conclusions

Double-absorption technology can be used to meet the new Chilean regulations in a cost-effective, technically sound and sustainable manner.

Consider debottlenecking, energy recovery and capacity increase at the same time of emissions reduction.

Take advantage of the oportunity to improve your plant process design, equipment performance and materials of construction. Do not replace equipment “in kind”.

Scrubbing technologies are also available to meet the new standards.

EMISSIONS REDUCTION


Conclusions

Advantages, disadvantages and equipment requirements have been discussed for both options to reduce emissions.

The implementation technology upgrades requires careful evaluation of the existing plant to identify upgrade opportunities from the process engineering and mechanical layout points of view.

EMISSIONS REDUCTION


MUCHAS GRACIAS A TODOS!

EMISSIONS REDUCTION


the suitability of double absorption and scrubbing ... · pdf filethe suitability of double...

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