2 wsa technology for treatment

8/13/2019 2 WSA Technology for Treatment

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1

Torben Christensen

WSA technology for treatment of H2S and

SO2 gases producing sulphuric acid including

acid production based on molten sulphur

Presentation - Main contents

Introduction to the subject “WSA technology”

Treatment of the feed streams SO2, H2S and S

The basic concept of the WSA process

The detailed WSA process

Reference situation

Conclusion



2

WSA technology - “The concept”

Converts SO2 in off-gases into commercial-grade

sulphuric acid

Treats the off-gas in wet condition, i.e. no drying of the

off-gas is required

No consumption or additives

No production of waste products

Simple, efficient, reliable and competitive process

Hot combustion air

Aci dcooling

Product

acid

Cooling

water

SO2conversion

Gas

cooling

Aci d

conden-sation

H2S gas/

Molten

sulphur

Incineration

H2SO4 (gas) = H2SO4 (liquid) + 90 kJ/mole

HP superheated steam

Atmosph eric air Cool ing

water return

Clean process

gas to stack

H2S + 1.5 O2 = H2O + SO2 + 518 kJ/mole

Combustion

SO2 + ½O2 = SO3 + 99 kJ/mole

OxidationHydration

SO3 + H2O = H2SO4 (gas) + 101 kJ/mole

Condensation Large export of high pressure steam, 2-3 ton/ton acid produced

Low cooling water consumption, 8-9 m3/ton acid produced

Principles of the WSA process,

H2S and sulphur



3

Cooling

water returnHP superheated steam

Atmosph eric air

Hot air for p reheating

Aci d

cooling

Clean process

gas to stack

Product

acid

Cooling

water

SO2 rich

off-gas SO2conversion

Gas

cooling

Pre-

heating

Aci d

conden-

sation

H2SO4 (gas) = H2SO4 (liquid) + 90 kJ/moleSO2 + ½O2 = SO3 + 99 kJ/mole

OxidationHydration

SO3 + H2O = H2SO4 (gas) + 101 kJ/mole

Condensation No fuel consumption with an SO2 content above 3 % (vol.)

Low cooling water consumption, 8-9 m3/ton acid produced

Principles of the WSA process,

SO2

gas

WSA plant lay-out, H2S gas and sulphur

H2S gas

Steam

system

Superheated

steam

SO2converter

Acid pump

Acid cooler

Product acid

Combustion air Blower

Stack gas

Blower

WSA

condenser

Interbed

cooler

Interbedcooler

Gascooler

Incinerator

Air



4


H2S gas

Steamsystem

Superheatedsteam

SO2

converter

Acid pump

Acid cooler

Product acid

Combustionair Blower

Stackgas

Blower

WSAcondenser

Interbedcooler

Interbedcooler

Gascooler

Incinerator

Air




5

WSA plant lay-out, SO2

gas

Superheated

steam

SO2 gas

Heat

recoverysystem

SO2converter

Acid pump

Acid cooler

Product acid

PreheatingBlower

Stack gas

Blower

WSA

condenser

Interbedcooler

Interbedcooler

Gascooler

Heatexchanger

Air

WSA plant lay-out, SO2 gas

Superheated

steam

SO2 gas

Heatrecoverysystem

SO2converter

Acid pump

Acid cooler

Product acid

PreheatingBlower

Stackgas

Blower

WSAcondenser

Interbedcooler

Interbedcooler

Gascooler

Heatexchanger

Air



6

WSA plant lay-out, SO2

gas

WSA - Simple system, few components

Superheated

steam

Heatrecoverysystem

SO2converter

Acid pump

Acid cooler

Product acid

Combustion air/preheatingBlower

Stack gas

Blower

WSA

condenser

Interbedcooler

Interbedcooler

Gascooler

Air

SO2 gas



7

Catalyst layer

Interbed cooler

SO2

converter details

Heatrecoverysystem

SO2converter

400-420°C

265-290°C

Off-gas withH2SO4(gas)

400-420°C

400-420°C

Superheated

steam

SO2 gas

SO2 converter



8

SO2

converter incl. interbed cooler

Heat transfer system



9

WSA condenser - Principle design

Hot Air Outlet

Cooling AirInlet

Clean Gas Outlet

Product Acid Outlet

Acid GasInlet

Cooling air inlet

Clean gas outlet

Hot air outlet

WSA condenser details

Sulphuric acid

98%70% Acid

strength (%)

Acid gas inlet



10

WSA condenser erection




11





12


Installation of WSA condenser module



13

WSA condenser internals

WSA condenser internals



14

WSA acid cooling system

WSA acid cooling system



17

Typical scope of supply

License package (min scope)

Basic engineering of WSA plant (min scope)

Supply of proprietary equipment (min scope)

Catalyst (min scope)

Detailed engineering of WSA plant

Supply of IBL equipment of WSA plant

Supervision during erection and commissioning

Clean off-gas

0.1% SO2

(98.1% reduction)854 MTPD H2SO4

(98% purity)

SO2 gas - Pb/Zn plant at Kazzinc, Kazakh.

6.5% SO2

5% H2O

14% O2

125,000 Nm3/hr

WSA

Steam

7 ts/hr

15 barg



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Clean off-gas

175 ppm SO2(99.2% reduction)

168 MTPD H2SO4

(98% purity)

H2

S gas - gasification plant, Guanghui, China

51.5% CO2

4,7% H2S

9,340 Nm3/hr

WSA

Steam

26 ts/hr

4 barg

Clean off-gas

350 ppm SO299.5 % reduction

300 MTPD H2SO4(98% purity)

Sulphur burn. - acid plant, Meranol, Argentina

4,025 kg/h S

WSA

Steam

xx ts/hr

40 barg



19

Salient features of WSA

More than 99% of the sulphur content is recovered

Sulphur is recovered as concentrated sulphuric acid of

commercial quality (~98%)

Very low consumption of cooling water

No waste products or waste water

No consumption of chemicals or other additives

Salient features (cont.)

Efficient heat recovery

– (superheated high pressure steam export)

Wide turn-down range (1:10)

Simple lay-out, small plot area

Low investment and attractive operating economy

One point responsibility



Any questions ?

Thank you for your attention!

2 wsa technology for treatment

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