regenerative so2 capture: recovering the future€“ energy recovery system further reduces steam...

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Regenerative SO2 Capture: Recovering the Future

Presented by: Steve Puricelli

MECS, USA

3 April 2013


2

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We Are About To Turn Sulfuric Acid On Its Head!


Safety ContactSO2 Toxicity

Odor threshold: 0.5 ppm

OSHA Permissible Exposure Limit (PEL) = 5 ppm (weighted, 8 hr avg)

Slight irritation to eyes and throat = 10 ppm

Coughing and eye irritation = 20 ppm

Strong irritation =30 ppm

NIOSH Immediately Dangerous to Life and Health (IDLH) = 100 ppm

Death in a few minutes = 600 to 800 ppm


Introducing SolvR!

What is SolvR?

• A regenerative SO2 recovery system

• What sets SolvR apart from other technologies?

• New high capacity, environmentally friendly solvent

• Lower capital expenses (CAPEX)

• Lower operating expenses (OPEX)

• Not just for sulfuric acid!

• Applicable to a variety of tail gases

• Over a wide range of concentrations

• High removal efficiency (<20 ppm)


Acid

Flue Gas

SO2

Absorber

Stack

Na2SO

4

To Existing

Drying tower

SO2 Stripper

Crystallizer

Water

Water Purge

To drying tower

Heat Recovery System

Steam

Auxiliary

Reboiler

The MECS Regenerative Recovery Process for SO2


Recovers SO2 From a Variety of Tail Gases

Process

Reaction with base

Regenerative Absorption

Direct reaction to sulfuric

Conventional Sulfuric Acid

SO2 in Gas stream (% Vol)

0.01 0.02 0.05 0.1 0.2 0.5 1 2 5 10

Typical sulfur dioxide concentration in flue gas


Why is SolvR Different?

• Environmentally friendly, high capacity solvent

• Readily available solvent

• Used in food processing

• Capable of high removal efficiencies

• Generates minimal byproducts

• Lower CAPEX

• Utilizes FRP and Low alloy materials

• Smaller plot space

• Lower OPEX

• reduced energy usage

– Regeneration done at atmospheric pressure

– Uses low pressure steam

– Energy recovery system further reduces steam usage

• Minimal solvent losses

– Robust and stable solvent

SO2SOSO22


High Efficiency Solvent


Historical solvents

• Chemical Solvents (reversible chemical reactions)

• Water (SO2 + H2O <->H2SO3)

• Wellman-Lord (Na2SO3 + SO2 <-> NaHSO3)

• Amines (R-NH-SO3 <-> SO2)

• Physical solvents (Henry’s law)

• DBBP

• Tetraglyme

– (competitive when SO2 >1 vol%)

• New MECS solvent

• Na2-R (Na2-R-SO3 <-> SO2)

TOP SECRET


High Capacity Solvent

Solvent Loading as a Function of Gas Concentration

0 3500

SO2 Concentration (ppm)

So

lven

t L

oad

ing

35C

100C


Capable of Very Low SO2 Emissions

0

100

200

300

400

500

600

700

800

0 0.2 0.4 0.6 0.8 1 1.2

Lean Solvent SO2 Concentration (wt%)

SO

2 G

as e

xit

co

ncen

trati

on

(p

pm

)


Summary of the Solvent

• Solvent has a high capacity for SO2

• Reaches maximum loading with low levels of SO2

• Desorbs readily at low temperatures

• Capable of high levels of SO2 recovery

• Solvent is environmentally friendly

• Commonly used in food processing


Lower Capital Expenditures


Simplified Flow Sheet Means Lower Capital Cost

Double Absorption

Equipment

SolvR

Equipment

Towers:

• Final Absorbing Tower

• FAT acid cooler

Towers:

• Absorber

• Stripper

• Interchanger

• Stripper reboiler

• Trim cooler

Vessels

• Converter pass 4

• Pumptank

Vessels

• None

Gas/Gas heat exchangers

• Cold interpass exchanger

• Hot interpass exchanger


• None

Misc:

• Catalyst

Misc.

• None

7 5


Solvent CorrosivityImpact on Materials of Construction

304, CORT AW, A36, A516, A285

Coupons after recovery


Materials of Construction

Materials exhibiting <1 mil/yr (<0.025 mm/yr)

• Low grade stainless steels

• FRP and common plastics

A wide range of materials can be selected to suite individual applications.


Summary of Capital Expenses

• Less equipment is required

• Large and expensive pieces of equipment are eliminated

• Corrosion rates are low

• Equipment can be constructed of common materials


Lower Operating Expenditures


Estimated Steam Requirements

1

1000

0 16Steam/SO2 ratio

SO

2 O

utl

et

(pp

m)

Standard

Energy Recovery

Heat Recovery System

reduces steam by 2/3!


SOSO22

Minimal Solvent Makeup Requirements

• Oxidation does not degrade solvent

• Approximately 0.3% of throughput converted to Na2SO4

– (Na2-R + SO4 -> Na2SO4 + R)

• Regeneration removes sulfates from solvent

• Minimal solvent losses with sulfates

• Minimal stack losses due to extremely low volatilitySOSO22

SOSO22

OO22 OO22

OO22

HH22SOSO44HH22SOSO44


Minimal Oxidation

NOx introduced


Solvent regeneration


Summary of Operating Expenditures

• Steam Consumption

• Operates with low pressure steam (<1 barg)

• Energy recovery system reduces steam usage by 2/3

• Solvent is stable and robust

• Minimal stack losses

• Minimal losses during regeneration

• Solvent is not oxidized and is not reactive with SO3 or H2SO4

• Byproduct production is low


Minimal Environmental Impact

• Sodium sulfate

• Produces a solid or liquid byproduct stream

• Readily disposable in sewer or waste water treatment plant

• Water with ppm levels of SO2

• Can be used as process water for sulfuric acid

• Volume is generally low, but dependant on

– Evaporation/condensation in the absorber

– Use of live steam for stripping


SolvR Applications


Technology Application Ranges

Process

DynaWave

SolvR and Clausmaster

Sulfox

Conventional Sulfuric Acid

SO2 in Gas stream (% Vol)

0.01 0.02 0.05 0.1 0.2 0.5 1 2 5 10

Typical sulfur dioxide concentration in flue gas

Combined regenerative technologies cover a broader range


SolvR Applications

• Bolt on to existing technologies (SO2 is recycled to existing plant)

• Sulfuric acid plant tail gas

• SRU tail gas

• Application to traditional scrubbing markets

• Gases with low levels of SO2

– Smelter fugitive gases

– Combustion process with high sulfur fuels

• Development of hybrid technologies

• Improved HRS


Advantage in Sulfuric Acid Conversion to Double Absorption

Double Absorption

Equipment

SolvR

Equipment

Towers:

• Final Absorbing Tower

• FAT acid cooler

Towers:

• Absorber

• Stripper

• Interchanger

• Stripper reboiler

• Trim cooler

Vessels

• Converter pass 4

• Pumptank

Vessels

• None


• Cold interpass exchanger

• Hot interpass exchanger


• None

Misc:

• Catalyst

Misc.

• None

Relative Equipment costs 1.00 0.50

∆P = 15 kPa ∆P = 5 kPa


First Reference Plant

Southern States ChemicalSavannah, Georgia USA

• More cost effective than conversion to double absorption

• Designed to test for high SO2 recovery

• Expected startup is January 2014


Claus Applications


Advantages of SolvR in Claus Tail Gas Applications

No reducing gas generator required

No reactor required


Advantages of SolvR in Claus Applications

• No reducing gas required

• Less equipment

• TIC expected to be lower by 10% or more

• No catalyst to replace

• Lower pressure drop

• Recycle SO2 reduces air requirements

• Potential capacity increase


Smelter Fugitive and Traditional Scrubbing

Applications


SO2 + O2 = SO3

SO3 + H2O = H2SO4Flue Gas

To Atm

SO2, H2OAIR

H2SO4

Q

H2O (l)H2O (g)

RESIDUAL SO2

Typical Flue Gas Configuration

SolvRSulfuric

acid


Hybrid Sulfuric Acid Plants

Maximizing Energy Recovery HRS + SolvR


Hybrid Sulfuric Acid Flow Scheme

To SOLVR


Relative Overall Order of Magnitude Savings2,400 MTPD

Conventional Conventional SolvR + NPV ΔΔΔΔwith HRS HRS Conventional

Overall TIC 1.0 1.1 1.1 ($8 MM)

Parasitic power (MW) 4.3 4.3 3.5 $3.5 MM

Power generation (MW) 33 39 42 $38 MM

SolvR steam (MW) (1.6) ($7 MM)

Total NPV $26.5 MM

Notes: 1. Discount rate = 9% for 30 years2. Electricity = $$0.05/kWH3. LP steam = $8/MT4. SolvR steam = 16 T/hr at 5 T/T


Summary

• Lower CAPEX• FRP and Low alloy materials• Smaller footprint

• Lower OPEX through • reduced energy usage

– Regeneration done at atmospheric pressure– Uses low pressure steam– Energy recovery

• Environmentally friendly solvent• Readily available solvent, • Used as a food additive

• Improved SO2 recovery for other processes• Claus• Metallurgical applications• Other flue gases


Questions?

regenerative so2 capture: recovering the future€“ energy recovery system further reduces steam...

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