CO2 Capture at the 

Kemper County IGCC Project

2011 NETL CO2 Capture Technology Meeting
Kemper County IGCC Overview

Plant Site

Kemper Lignite Composition

Average Min Max

Heat Content btu/lb 5,290 4,765 5,870

Moisture % 45.5 42 50

Ash % 12.0 8.6 17

Sulfur % 1.0 0.35 1.7

 2x1 Integrated Gasification Combined Cycle (IGCC)

– 2 TRansport Integrated Gasifiers (TRIGTM)

– 2 Siemens SGT6 - 5000F CTs

– 1 Toshiba Steam Turbine (Tandem Compound Double Flow)

– 582 MW peak and 524 MW on syngas

– Heat Rate 11,708 Btu/kWh (29.5% HHV Efficiency w/ CO2 control 

and 40+% moisture coal)

– Selexol for H2S and CO2 removal

– 65+% CO2 capture (~800 lb/MWh emission rate)

– Mine Mouth Lignite

 Owner & Operator: Mississippi Power

 Over $2 billion capital investment

 Commercial Operating Date: May 2014

 Use treated effluent from Meridian as makeup water

 By-Products (TPY)

– ~3,000,000 - Carbon dioxide used for EOR

– ~135,000 - Sulfuric acid

– ~20,000 - Ammonia
Proposed Kemper 

County IGCC Project 

Map

• ~70 miles transmission

• ~ 60 miles CO2 pipeline (for EOR)

• ~5 miles natural gas pipeline

• ~31,000 acre mine site

• ~2,900 acres plant site

• ~ 30 miles treated effluent line

Plant Site

New CO2

Pipeline

Meridian
TRIGTM

Attributes/Advantages

 Simple, well established design

– Based on technology in use for 70 years

 Either Air- or Oxygen-blown

– Air for power

– Oxygen for liquid fuels and chemicals

 High Reliability Design

– Non-slagging design:

 Provides 10-20 year refractory life, 

 Eliminates black water system

 Provides non-fouling syngas cooler operation

– No burners to fail and be replaced

– Dry dust removal eliminates gray water system

 Lower Fuel Costs

– Coarse, dry coal feed allows:

 Fewer, lower power pulverizers, and 

 Less drying than other dry-feed gasifiers

– Cost-effective using high moisture, high-ash, low rank 

coals (PRB and lignite).

 Excellent Environmental Performance

– Lower water use compared to pulverized coal (PC)

– Excellent emissions performance

– Easier to permit compared to PC 

– Lower cost carbon capture compared to PC
Gasifier

Island

Combined

Cycle

COAL

PROCESS

AIR

COMPRESSOR

HIGH

TEMPERATURE

SYNGAS

COOLING

CO2 AND 

SULFUR 

REMOVAL

COAL

MILLING &

DRYING

HIGH

PRESSURE

COAL

FEEDING

SOUR

WATER

TREATMENT

AMMONIA

RECOVERY

RECYCLE

GAS

COMPRESSION

GAS

TURBINE

STEAM

TURBINE CONDENSER

SYNGAS

SWEET SYNGAS

ANHYDROUS VENT GAS

AMMONIA

ACID

GAS

RECYCLE GAS

COARSE

G-ASH

HP BFW

HP STEAM

TO STACK

HP, SUPERHEATED

STEAM

CONDENSATE

MERCURY

REMOVAL

TRANSPORT

GASIFIER

AIR

POWER

POWER

FINE

G-ASH

WATER GAS 

SHIFT 

REACTION

CO2

Summary Flow Diagram

CO2

COMPRESSION

AND DRYING

CO2

PARTICULATE

COLLECTION

LOW

TEMPERATURE

SYNGAS

COOLING

SWEET

SYNGAS

SOUR WATER

WSA 

PROCESS

SULFURIC

ACID

WATER FROM

COAL DRYING

HEAT RECOVERY STEAM GENERATOR
Evolution of Acid Gas Removal at 

Kemper County IGCC

 Originally, no CO2 removal. H2S removed with amine.

 With CO2 removal added to scope, design team explored three main 

options based on a physical solvent:

– 25% CO2 removal (1,500 lb CO2/MWh). 

 Case 1: No WGS, Selexol for sulfur removal, amine for CO2

 Case 1A: One stage of WGS, with Selexol for all acid gas removal. 

– 50% CO2 removal (1,000 lb CO2/MWh). 

 Case 2: One Stage WGS with steam injection with Selexol for AGR. 

 Case 2A: Case 1A retrofitted to Case 2 in 2020

 Case 2B: Case 1 retrofitted to Case 2 in 2020. 

– 65% CO2 removal (800 lb CO2/MWh).

 Case 3: Two stages WGS with steam injection and Selexol for AGR.
Physical Solvent Selection

The operating costs for an amine were too expensive, due to high steam 

usage for regeneration. Therefore, a physical solvent was selected. 

Selexol Rectisol

Volatility Low High

Solvent Price High Low

Emissions Concern No Yes

Both good options, but Selexol was chosen. 
Commercial Selexol Plant

H2S 

Absorber CO2

Absorber

Lean-Rich 

Exchanger

Regenerator

Flash 

Drums

Concentrator

Reboiler
Lean Solvent

Sour Syngas

Rich Solvent

H2S Absorber

Lean/Rich

Exchanger

H2S

Concentrator

Recycle Gas

H2S

Regenerator

Flash

Drum

Condenser

Reflux

Acid Gas

Flash

Drum

Steam-Heated

Reboiler

Steam Heat

Lean Solvent

Flash Gas

Flash Gas Compressor

LP Flash Gas

To WSA

Semi-Sweet Syngas

CO2

Captured

CO2 Absorber

Sweet Syngas

Semi-Lean Solvent

Lean Chiller

Semi-Lean Chiller

HP Flash

MP Flash

LP Flash

CO2 Recycle

Compressor

CO2

Recycle

Lean Solvent

Loaded Solvent

•Two Stages WGS

•Selexol Physical Solvent

•Refrigerated to 40 F

•Carbon Capture: >65%

•CO2 Emissions: 800 lb CO2/MWh

•Yield: >3 MM Tons/yr CO2

•CO2 compressed and used for EOR

•Acid gas converted to sulfuric acid 

via WSA process.

CO2 Capture Scheme for 800 lb/MWh
Cooling Towers

Sulfuric Acid 

Production

Sulfur/CO2

Removal

Coal Dome

Flare

Coal Loading 

Hoppers

Process Air 

Water Compressors

Treatment

Coal Prep

Gasifier Structure: 

Gasifiers, Syngas 

Cooling/Filtration

2 x 1 Combined Cycle

Control/Admin 

Bldg.

Warehouse

Water Supply Pond

Electrical Switchyard
Fluid Bed 

Dryer 

Sulfuric System 

Acid 

Production

CO2 and H2S 

Removal

Gas 

Turbines

HRSGs

Steam 

Turbine

Air 

Compressors

HP Coal 

Feeders

Gasifiers (2)

Nitrogen 

Plant

Ammonia 

Production
CO2

Compressors

CO2 Flash Drums (8)

Process Air 

Compressors (4)

WGS Reactors

Syngas 

Humidifiers COS Hydrolysis

NH3 Removal

Mercury Adsorbers

Sour Water/NH3 Recovery 

System H2S Absorbers (2)

AGR Regenerators (2)

Crushed 

Coal Silos

Coal Mills (6)

Back-pulse 

Surge Drums

Particulate Collection Device (PCD)

Dry Ash Filters (4)

Gasifiers (2)

Main Syngas Coolers (4) 

Warehouse

Admin. 

Bldg.

Flare Derricks

Steam Turbine

HP Coal Feeders (12)

CO2 Absorbers (6)
Project Status

 On June 3, 2010, the Mississippi Public Service 

Commission certified the project. 

 Mississippi Power has entered into CO2 offtake 

agreements with Denbury Onshore and Treetop 

Midstream Services, LLC

 MDEQ issued the final PSD permit on March 9, 2010. 

 Procurement: All major equipment awarded.

Equipment fabrication underway. 

First major pieces arriving on site. 

 Construction: Site cleared and graded. 

Foundation and pedestal work underway. 

Sumps, duct banks, underground piping 

being installed.
Kemper Procurement Update

2nd Quarter - 2011

Top of CO Base of CO2 Absorber 2 Absorber

Base of Concentrator Lean/Rich Exchanger Plates
Kemper County IGCC Construction Update

1st Quarter - 2011

Storm Drains

Electrical Duct Banks Fire Protection Piping

Began Installation of Underground Electrical and Mechanical Systems
Deep Foundations/ Major Equipment Foundation Installation/U/G Utilities

Steam Turbine Columns

96” Circ. Water Pipe

AGR Area Sumps

Kemper County IGCC Construction Update

2nd Quarter - 2011
Kemper County IGCC Construction Update

End of 2nd Quarter - 2011

Circulating Water Pipe

Gasifier Pile Caps/

Deep Foundation Installation

Steam Turbine Operating Deck 

Plant Site as of July 2011
Summary

 Physical solvents were selected for the Kemper design due to 

reduced steam usage. 

 The facility will use Selexol coupled with two stages of watergas-shift, resulting in a CO2 emission rate of 800 lb/MWh (a 

nominal 65% reduction). 

 3 million tons/year of CO2 captured at the Kemper site will be 

used for EOR, and will meet offtaker specifications. 

 Commercial operations are expected in May 2014.