Acid Roundtable 2013 Scottsdale

A double- track road: acid plant size (The Mouse and the Elephant)

Peter Ernst, Head of Sulphuric Acid Departement

The Mouse and the Elephant?

?

?

The Mouse and the Elephant!

5000 t/d

250 t/d

...when it comes to plant size, it needs to be considered: §  Economics §  Design

§  Process §  Mechanical

§  Supply & Construction §  Fabrication §  Construction §  Logistic

§  Operation & Commissioning §  Example: 250 tpd „skid“ plant vs 5,000 tpd „Mega“ plant

...from small to large

0

1000

2000

3000

4000

5000

6000

7000

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9000

1971

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1975

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1977

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80

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1983

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1987

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1991

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1995

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1999

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2001

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2003

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2009

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10

Capacity (Tpd Mh)

Incitec Pivot (WMCF)

Vale (Goro Nickel)

(Chart based on OUTOTEC reference list; S and met. Gas based)

3 x 5,000 tpd Ma‘aden Complex

Development of plant sizes

Economical impact

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0 0.5 1 1.5 2 2.5 3

Cos

t [%

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Plant Size

Economical impact

250 tpd (tailored) 5,000 tpd

Standarization vs Customization

Capex vs

Operational flexibility/availability

250 tpd (standard, skid)

5,000 tpd

Eng.

Supply

Constr.

Eng.

Supply

Constr.

Eng.

Supply

Constr.

§  Process Design §  Optimization of process conditions, e.g.

SO2-content

§  Optimization of process conditions of equipment/plant sections

§  Mechanical Design §  Size limitations for certain equipment due

to mechanical limitations §  Different behaviour of process equipment

§  Gas and liquid distribution challenges

§  Flow dynamics differ with increased sizes

Design

Impact of SO2 concentration

Supply & Construction §  Fabrication

§  Degree of pre-fabrication limited by size/weights

§  Lead times for material

§  Structural integriy decrease while fabrication tolerances increase

§  Transportation §  Allowable dimensions re port facilities, land

transportation

§  Construction §  Availability and quality of constr. equipment and

manpower

§  Infrastructure (e.g. camp accomodation, sufficient local fabrication areas, work-shops)

Evaluation of pre-fabrication vs site fabrication

Operation & Commissioning

§  Large plants offer different concepts for equipment/units

§  Usually different production buffer concepts (day

vs week) §  Larger distances (....in case of troubles)

§  Lager sizes show different plant behaviour §  Learning Tools, eg. dynamic training simulator

Learning Tools

§  Dynamic Plant Simulator §  Basic Operator training

§  Familiarize with „new“ plant

§  Appropriate reactions to process upsets

§  Facilitate commissioning

Commissioning Experience

1500

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2500

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3500

4000

4500

5000

0 5 10 15 20 25 30 35 40

t/d

Days

Plant 1

Commissioning Experience

1500

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2500

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3500

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4500

5000

0 10 20 30 40 50 60

t/d

Days

Plant 1 Plant 2

Commissioning Experience

1500

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0 10 20 30 40 50 60 70

t/d

Days

Plant 1 Plant 2 Plant 3

Example – Plant Concept

Size/Type 250 tpd/skid plant 3 x 5,000 tpd Eng./ Standard pre-design (red. of cost ) Customized/tailored Clients request Partly considered/low flexibility Incorporated/high flexibility Fabrication Prefabricated Site fabrication/prefabricated

(Technology center) (global sourcing) Transport/ Standard container Highly complicated logistics Construction Minimized (red. local resorces) Maximized (all local res. needed) Maintenance Standarized components/ Highly customized equipment

sub-systems

Example – Plant Concept

Drying and absorption Section

Converter Section

Drying and absorption Section

Converter Section

S-melting/ Filtration

S-melting/ Filtration

Example – Plot plan

120m

90m

Example – Plot plan

120m

90m 31m

20m

Above ground S-melter

- Capacity: 80 t/h at maximum - Heating coils removable - Easy access for maintenance and cleaning of tank - Integrated pre-coating

compartment

Sulphur filter and storage - Main „leaf-type“ filter - Additional polishing filter - Day storage tank

Sulphur melting and Filtration Neither large nor small plants have „special“ requirements

Example – Combustion Concept

Drying Tower

Combustion Furnace & Waste Heat Boiler

Small sized plants follow „conventional“ plant design Specific features for large sized plants: § Combustion Concept:

§  Sulphur will be combusted at 18 vol.-% SO2 and ≈1.600 °C

§  SO2 gases will be cooled in water tube boiler (WHB)

§  Additional air will be mixed to SO2 gas after WHB to achieve required O2/SO2 ratio

Example – Combustion Concept Specific features for large sized plants: § Boiler Concept:

§  ~1700 °C gas temperature §  > 3500 mtpd §  References in power plants

(up to 2000 °C) §  All sizes can be realized with single

boiler §  Superheater or economizer

elements applies to boiler concept (e.g. temperature control by pre- superheater)

§  Cold bypass possible

§ Burner system: §  Luro II burner

§  Spinning cup design,

§  Capacity: up to 35 t/h per burner

§  Operating range: 15 – 110 %

§  Efficient operation (no steam leaks etc)

Example – Absorption Section

Specific features for large sized plants: •  Tower design according to „conventional“ plants:

•  Bricklined towers •  Conservative Packing (>3.5 m) •  Standard distributor •  Common acid system, sea water coolers

•  Maximum tower diameter limited by flow patterns and mechanical limitations; larger capacities would require different design.

Example – Absorption Section

Specific features for small sized plants: •  Tower design limited by „container“ dimensions:

•  Venturi Absorber design •  Seperate casing for Candle filters (could serve as

pump tank) •  Material of construction: SS310 / SX •  Common acid system •  Acid cooler options: anodic protected s&t or SX cooler

Example – Converter Section

Specific features for large sized plants: §  Converter fully welded stainless steel design from 304H, 321H

§  Outside diameter of converter of 17 m

§  Integration of internal heat exchangers (up to three internal heat exchanger) into converter

§  First pass preferred on top

§  Radial gas distribution for 1st and 4th pass

Example – Converter Section

Specific features for small sized plants: §  Converter dimension limited by container size

§  Fully welded stainless steel design from 304H, 321H

§  Two beds per converter bullet with integrated boiler elements, (SH – Bed III – Re-Heat –

Bed IV – ECO)

§  All accesses to bullets standarized

Re-Heat Exch.

Bed 2

FAT

A standard plant solution will save delivery time and capex cost - Impact on Capex is significant for smaller plants, -  Pre-fabrication of complete plant units reduces site activites and ensures good workmanship

For large (mega plants) process customization is critical for capex and opex optimization

- Opportunities for specific developments of known plant sections - „Economies of scale“ vs „operational availability/flexibility“

Conclusion