CO2 Recovery Technology

8/9/2019 CO2 Recovery Technology

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INTERNATIONAL CONFERENCE & EXHIBITION

NITROGEN & SYNGAS

28 FEB 3 MARCH 2010

The Gulf Hotel, Bahrain

Current Status of MHIs CO2Recovery Technology and Road Map to

Commercialization for Coal Fired Power Plant Application

Naoya Okuzumi and Ronald Mitchell

Environmental & Chemical Plant Division, Plant and Transportation Systems Engineering & Construction Center,

Mitsubishi Heavy Industries, Ltd., 3-3-1 Minatomirai, Nishi-ku, Yokohama 220-8401, Japan

Abstract

Mitsubishi Heavy Industries, Ltd. (MHI)and Kansai Electric Power Co. KEPCO, 2nd

largest utility company in

Japan, initiated collaboration in 1990 in response to concerns relating to Global Warming. This industrial alliancehas led to the development of proprietary technology aimed at reducing atmospheric emissions of carbon dioxide(CO2

1) from the combustion of fossil fuels, through the mergence of specific expertise and capital. MHI and

KEPCO have developed, and continue to develop, highly advanced PCC2solvents, processes and special equipment

to further refine and enhance certain process features and to reduce the energy penalty associated with CO2capture.

MHI is a world leader in the field of PCC technology which stems from almost 20 years of RD&D3

. In additionMHI also has also been awarded an increasing number of commercial CO 2capture plants and we currently have inexcess of 20 years of cumulative commercial operating experience.

MHI currently has six (6) commercially operating PCC plants in the chemical and fertiliser industry, up to 450 T/D 4.This experience includes CO2capture from a natural gas and heavy oil fired boiler and natural gas steam reformers.MHI has also recently been awarded an additional three (3) commercial projects, currently under construction andexpected on stream within the next few years.

The paper introduces the recent status of process technology and the history of the technology improvements that

will enhance the performance especially those applied for large scale CO 2capture from coal fired boilers, advancedconcept relating to heat and process integration starting from power generation system, air quality control system

and CO2compression for the delivery of advanced power generation and environmental equipment.

Keywords;MHI, global warming, carbon dioxide, fossil fuels, CO2 capture plants, coal fired boilers, process

integration

1.Introduction

The stationary energy sector is the largest net contributor of greenhouse gas emissions, with most emissions

attributed to coal-fired power stations. These emissions can be reduced by deploying CCS5 technology into new


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DRAFT AS OF 10 NOVEMBER, 2009 2

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1CO2 Carbon Dioxide2PCC Post Combustion Capture3 RD&D Research, Development and Demonstration4T/D Metric Tons Per Day5 CCS Carbon Capture and Storage

coal-fired power stations and retrofitting to existing facilities. Widespread deployment of CCS may alsoallow nations around the world to continue using important domestic fossil fuels such as coal in an economic andenvironmentally sustainable way.

Mitsubishi Heavy Industries, in collaboration with Kansai Electric Power Company, has developed an advanced flue

gas CO2 recovery technology capable of significantly reducing emissions from industrial power plants, the resultfrom almost 20 years of RD&D.

MHI has now commercialized the proprietary Kansai Mitsubishi Carbon Dioxide Recovery, or KMCDR, Process,

which requires significantly lower energy to capture CO2. MHI has been awarded an increasing number of

commercial CO2capture plant contracts and currently has in excess of 20 years of cumulative commercial operatingexperience. MHIs first commercial CO2 capture plant, using the KMCDR

process, commenced operation in

Malaysia in 1999. Since delivery of the Malaysian plant, MHI has constructed many CO2capture plants worldwide,notably in Japan, Asia and the Middle East.

With regards to coal fired flue gas CO2capture MHI, in collaboration with a Japanese electric utility, conducted a

demonstration project to capture CO2from flue gas at a coal fired power plant. The project provided much knowhow, in relation to coal fired flue gas, following successful long term operation. MHI has also formed a partnershipwith Southern Company, one of the largest US electric utilities, to build a 500 T/D CO2capture demonstration plant,with operation commencing in 2011. This strategically important project aims to develop commercial CO2recovery

technology for coal fired electric power companies, along with the long term storage of CO2in a saline aquifer deepunderground.

MHI has extensive power systems, environmental plant and CO2compression plant experience, including the supplyof more than 200 commercial Flue Gas Desulphurization (or FGD) units. Unparalleled know how generated fromour commercial FGD experience has aided in the design of commercial flue gas CO2capture plants for natural gasapplications. MHI has completed the basic engineering for large scale CO2capture from natural gas fired powergeneration facilities and following large scale demonstration of the KMCDR Process will be ready to providecommercial CO2recovery plants for the coal fired electric utility sector.

Additionally MHI has also developed advanced process and heat integration schemes to further reduce the energypenalty of the CO2capture process when integrated with a power plant. These strategies will continue to improvethe economics of CCS as a viable technology to address global CO2emissions.

Through an increasing number of worldwide CCS projects and the development of reliable, economical newtechnologies, Mitsubishi Heavy Industries continues to provide significant contributions to aid in mitigating globalwarming and thus helping to ensure the sustainable future of our planet.

2. Commercial CO2capture plants

The experience gained from the deployment of several commercial plants has been invaluable in strengthening theknowledge of CO2capture at a range of sites throughout the world.

Six major MHI CO2capture plants are currently under operation (Fig 2.1) in the chemical and fertilizer industrywith another three under construction (Table 2.1).


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Additionally KS-1

offers superior CO2 absorption and regeneration, lower degradation and a reduced circulationrate when compared to other amine based systems. All of these features lead to decreased operating costs.

Importantly, KS-1

together with the patented improved CO2recovery process which utilizes the heat of the leanKS-1

solvent leads to a 30% reduction in steam consumption over the conventional MEA process.

4. The MHI post combustion CO2capture process

MHI has concentrated its extensive research and development programs on the use of advanced sterically hinderedamines and the post combustion, chemical absorption process in particular. MHIs post combustion technologyprocess consists of three main sections: the flue gas cooler, the absorber (for CO2 recovery) and the stripper (forsolvent regeneration). A process flow figure of the MHI CO2 recovery process is represented in Fig 4.1

The main function of the Flue Gas Cooler (Quencher)is to cool the flue gas prior to entering the CO2 absorber.

The lower flue gas temperature increases the efficiency of the exothermic CO2 absorption reaction and minimizesKS-1

solvent loss due to gas phase equilibrium increases.

The CO2Absorber has two main sections, the CO2absorption section (bottom section), and the treated flue gaswashing section (top section). The conditioned flue gas from the FGWC flows upward through structured, stainless

steel packing material while the CO2lean KS-1solvent is distributed evenly from the top of the absorption section

onto the packing material. The flue gas comes into direct contact with the KS-1solvent and CO2in the flue gas is

absorbed. The CO2 rich KS-1solvent (rich solvent) is pumped to the CO2Regeneration unit for steam stripping.

The clean flue gas then moves up into the treated flue gas washing section of the absorber. This section is where theflue gas is again cooled to maintain water balance within the system and the clean flue gas then exits the top sectionof the CO2Absorber. The rich solvent is pre-heated in a heat exchanger using heat from the hot lean solvent comingfrom the bottom of the CO2Stripper.

The heated rich solvent is then introduced into the upper section of the CO 2Stripper (Regenerator), where it willcome into contact with low pressure stripping steam of around. The rich solvent is then stripped of its CO 2contentand is converted back into lean solvent. The high purity CO2 (>99.9%) exits the top of the stripper vessel and iscompressed and dehydrated, prior to transportation. Once stripped, the now lean solvent is cooled and reintroducedto the top of the absorption section of the CO2Absorber unit.


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C.W.

C.W.

Steam

Reboiler

C.W.

ABSORBER

Cooling Tower

Deep FGD

Flue Gas

Outlet

Flue Gas

STRIPPER(Regenerator)

CO2 Purity 99.9 %

Pre-treated Flue gas

Figure 4.1. Process flow of MHI CO2recovery process showing major vessel components.

5.CO2capture from a coal fired boiler

As highlighted by many of the worlds climate and energy experts, including the IPCC6 and IEA

7, there is an

urgent need to address CO2emissions from coal fired power plants. Coal fired power generation is expected to formthe dominant part of the fuel energy mix for the foreseeable future (Figure 5.1).

Figure 5.1. 2009 IEA energy outlook showing the expected dominance of coal for energy production by 2030.

In response, MHI constructed a CO2capture pilot plant in 2002, with a capacity of 1 T/D, capturing CO 2from coal-

fired flue gas at the Hiroshima RD&D Center. MHI subsequently built a larger pilot plant at 10 T/D scale capturingCO2via a slip stream from the 1000MW (2 x 500MW units), J-POWER

8coal fired power station in Matsushima,

Japan, with grant funding (50% of project costs) from RITE9and cooperation from J-POWER.

Long term operation of this plant has enabled MHI to observe the influences of coal fired flue gas impurities and

develop countermeasures for these items. It is only through actual in-situ demonstration testing that some of theseinfluences were identified and subsequently resolved through the deployment of specific countermeasures. MHI hascompleted nearly 6,000 hours of near-continuous operation of this facility and has gained significant know how with

regards to the impact of specific impurities and the countermeasures necessary to abate these impacts.

5.1 Outline of the coal fired CO2capture demonstration plant

Table 5.1-1, Figure 5.1-1 and Figure 5.1-3 show the plant specifications, a flow diagram and a photograph of the

demonstration plant.

6IPCC - Intergovernmental panel on Climate Change7IEA - International Energy Agency8J-POWER - Electric Power Development Co., Ltd9RITE - Research Institute of Innovative Technology for Earth


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Table 5.1-1 Specifications of CO2 recovery Demonstration Plant

Figure 5.1-2 Flow Diagram of CO2Recovery Demonstration Plant

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Figure 5.1-3 Matsushima Demonstration Plant Photograph

5.2 Demonstration test results

a. CO2recovery eff ici ency and recovered CO2quantity

Following nearly 6,000 hours of demonstration operation, both CO2 recovery efficiency and recovered CO2quantities indicated equivalent or higher performance than our baseline prediction.

b. Heat consumption requir ed for CO2recovery

Performance of heat consumption required for CO2recovery: 730 to 820kcal/kg- CO2, which exceeded our original

baseline forecast. If MHIs Improved process is applied, the heat consumption is expected to decrease byapproximately an additional 15% to 630~700kcal/kg CO2, which is better performance than that recorded for naturalgas fired flue gas due to the high CO2concentration in coal fired flue gas.

c. Pur ity of recovered CO2

The results for CO2product purity shows that the KMCDRprocess can achieve a CO2 productpurity of >99.9%,

similar to our results for a natural gas-fired boiler.

d. I denti fying the in fl uence of dust

With a filter added to remove dust from the solvent, the dust concentration in the solvent does not increase thus thedust concentration of approximately 10mg/kg can be maintained. Our examination of the dust concentration in thesolvent, and the foaming tendency of the solvent, indicated no interrelation with either the absorber pressure loss or

the regenerator pressure loss. A dust concentration of 10mg/kg, or lower accumulated in the solvent, does not causeflooding.

e. I denti fying the in fl uence of SOx

The flue gas cooler provided with a desulfurization by caustic soda, removed 98% or more of the SO 2entering the

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system. This resulted in a SO2concentration at the CO2 absorber inlet of less than 0.1 ppm as per our expectation.Almost all the SO2at the outlet of the flue gas cooler was absorbed by the solvent and generated HSS*

8.

f. I denti fying solvent loss

The solvent loss recorded was close to our expectation. In this test, we assessed the solvent loss quantitatively from

the flue gas of the coal-fired boiler. We will apply the test results to actual projects.

6. Next steps and road map to commercialization for coal fired boilers

MHI has already gained considerable commercial experience in CO2 capture from natural gas-fired boilers.Combined with extensive experiences from large scale commercial FGD deployment and the flow dynamic dataobtained from our large scale multi pollutant test plant, MHI is ready to provide large scale, single train commercialCCS plants for natural gas fired installations, and intends to leverage this experience to commercialise CO2capture,from coal fired flue gas streams, through deployment of a large scale demonstration project in the US.

6.1 Large scale demonstration project

MHI together with southern Company plan to demonstrative the KMCDRprocess together with CCS at 25MW

scale (500 T/D) at Plant Barry in Alabama, US with plant start up in 2011.

Below are the key objectives of the project;

Industrial scale demonstration of integrated capture and compression

Focus on key engineering and operational issues for scale up

Build on MHI experience in gas processing

Through SECARB Phase III, validate southeastern saline geology for sequestration

Develop and validate subsurface models for predicting CO2behavior

Ensure protection of Under Sources of Drinking Waters and permanence of storage

Engage local and regional stakeholders to ensure a seamless commercialization process


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Plant Barry Power Station, AlabamaPlant Barry Power Station, Alabama

Figure 6.1-1 3D Model diagram of the MHI 500 T/D CO2capture plant proposed for demonstration at Plant Barry inthe US.

Following successful demonstration operation of the 500 T/D Southern Company demonstration plant, MHI expectsto apply significant know how and experience to the engineering design of commercial scale CO 2capture plants forcoal fired boilers as evidenced in Fig 6.1-2 below.

090806050403

MHI Pilot Test (1 t/d)

07 10 11 12 13 14 15

MHI Small Scale Demo (10 t/d)

Commissioning

Year 16

FEED Construction OperationProject

Organization

1817

Commissioning

Commercial CCS Plant US/EU (>3000 t/d)

090806050403

2 Operation phases completed

07 10 11 12 13 14 15

Southern Company & MHI Large Scale demo plant (500 t/d)

Year 16

FEED Construction OperationProject

Organization

1817

Commissioning

Know how from demo applied to future

commercial project

Figure 6.1-2. MHIs schedule for large scale coal fired demonstration and commercial CO2capture plant

MHIs has developed a technically robust road map to commercialization of CO 2capture technology for coal firedboilers which adopts a scale up approach in terms of our experience with coal fired flue gas. As defined in Fig 6.1-3

MHI is aiming to offer commercial scale CO2capture plants for coal application as early as 2015, following thesuccessful deployment of a large scale demonstration plant. This allows two learning by doing experiences prior

to 2020, by which it is expected commercial market based incentives will be in place to allow the wider adoptionand deployment of CCS technology. Following our experiences in related industries (eg FGD) we also expect cost



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reductions to occur prior to 2020 which will further facilitate the market place to invest in CCS as a reliableand effective means of reducing CO2emissions from large stationary sources, noting that the appropriateness ofdeploying CCS at specific sites will depend on several local factors such as the suitability and distance of storageoptions available.

FIRST Step:Large Scale

Demo

SECOND Step:Medium ScaleCommercial

THIRD Step:Full commercial deployment for new

build and retrofit

2010 2015 2020

(a) Numberof plants

Expected CCScost reductionwith incentives

$/T-CO2500 tpd25 MW

>3,000 tpd200 MW

Up to1,000 MW

CO2 emissionsBusiness as Usual

CCS CO2 emissionreduction

contribution

Time

(c) CCS cost$/T-CO2

(b) CO2emissions

(c)

(b)

Single Train Deployment


Figure 6.1-3 Scale up & road map for commercialization of PCC for coal fired boilers

6.Efficient Integration of CO2Recovery (PCC) Plant with the Power Plant

6.1.MHIs process improvements to reduce energy penalty of CO2capture

MHI has developed a number of plant and heat integrations schemes to further reduce the energy penalty of CO 2

capture. To reduce the steam consumption at the reboiler, we employ a unique concept to utilize lean solvent andsteam condensate heat for regeneration inside the stripper heating the semi-lean solution. Figure 7.1-1 shows theoutline of the KMCDR

improved process flow (Bold line section).

Through application of this process, the steam consumption is reduced by a further 15% compared with theconventional KMCDR

Process achieving 660kcal/kg CO2recovered. Other elements of the improved process are

also effective in recovering flue gas heat and the CO2compression heat to the CO2 regenerator to reduce the steamconsumption, utilizing the semi lean solvent heat integration concept shown in Figure 7.1-2 and explained below.

Figure 7.1-1 MHIs Improved Process Figure 7.1-2 Heat Integration in Power Plant

2 200 330 450 450 3000

Commerc e

(Natural Gas)

ial Experienc Commercial

(Natural Gas)

MHIs Operating Experience

1 tpd 10

P

(Natural Gas & Coal)

ilot scale experience

~3000500

Demo

(Coal)

Com cial

(Coal)

mer

PCC

Demo

US

PCC

Various

PCC

Norway

450

Black

coal

LP Turbine

Condenser

CO2Regenerator

CondenserCO2Reboiler

Boiler Feed Water Pump Boiler Feed Water Pump

Deaerator

CO2Regenerator

Heat Extractor

ESPAir Heater

Boiler

HP/MP

Turbine

Heat

Recovery&Solvent

Regeneration

Absorber

CO2Treated Gas

CW

CW

CO2Regenerator

(Stripper)

CW

CO2

RegeneratorCondenser

Steam

Condensate

Flue gas

Cooler

Flue Gas0.3 MPaG

Steam

Flue Gas

Blower

CO2

Lean

Solvent

CWReboiler


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6.2.MHIs additional heat integration methods to reduce requirements

MHI has identified further opportunities to reduce the impact on the net output via astute integration of the power

plant and CO2capture plant. MHI has investigated the following concepts which we aim to apply to future projects.

Heat integration between Power Plant and PCC Plant is shown in Figure 7.1-2.

(1)

Utilization of the waste heat of PCC plant for the power plant

The boiler feed water (BFW) is used to cool the regenerator condenser, which raises the temperature of BFW andsaves the low pressure steam consumption required to heat up BFW in the power plant, increasing the gross output.

(2) Utilizing the Recovery heat of the flue gas for the CO2recovery Process

Flue gas heat at the outlet of the air heater is recovered by the semi-lean solvent flowing inside of the heat extractor,which is one of the important components utilized in one advanced MHI concept titled MHIs High EfficiencySystem Proven Technology for Multi Pollutant Removal. In this case, the flue gas temperature is the importantparameter and the steam consumption in the reboiler is reduced by approximately 9% for the case where the flue gasis cooled from 158degC to 106degC by the heat extractor.

(3)

Utilization of the compression heat of the CO2for the CO2recovery process

Additional intercooler cooled by the semi-lean solvent is added at the outlet of each stage of the compressor where a

4 stage compression system is utilized. The CO2 compression heat is recovered by the semi-lean solvent to beutilized in the regenerator to reduce the steam consumption in the reboiler by approx 5%. MHI has extensivecommercial experience in delivering power systems, environmental plant and CO2compression plant on a globalbasis and accordingly has advanced know how in relation to the efficient integration of these core technologies (Fig7.2)

MHI Can Supply All Technology Advanced Integration

Boiler SCR ESPCO2

Capture

NOx Dust SOx CO2


FGD CO2 Capture Plant

CO2Compression

CO2

TransportFGD

Steam Turbine

rifugal Compressors

Cent

Coal Fired Power Station

Figure 7.2 MHI provides advanced integration for powers systems, environmental plant and CO2compression planttechnology


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7.Conclusion

(1) MHI has 6 commercially operating CO2capture plants with a further 3 plants under construction in the

chemical and fertilizer industries. Further, MHI is now ready to deliver commercial scale CO2capture plants forvarious natural gas fired applications.

(2)

For coal fired flue gas application, MHI has undertaken a significant, long term demonstration test in Japanand has accumulated almost 6,000 hours of operational experience, at 10 T/D capacity. The results confirm theapplicability of MHIs KMCDRProcess to coal fired flue gas streams.

(3) As a next step MHI, and our partners are deploying a 500 T/D coal fired CO 2capture demonstration plantin the US, complete with transport and storage. Following the successful demonstration operation, MHI will beready to deploy commercial scale projects for coal fired power stations.

(4) MHI has developed and continues to investigate heat and process integration schemes and concepts tofurther reduce the energy penalty associated with CO2 capture. MHI through our extensive commercial powersystems, environmental plant and CO2compression plant experiences is advancing the CO2capture technology toensure the improved economics of the process.

(5) MHI, through advanced RD&D and significant commercial CO2 capture plant experiences is working

diligently with our partners and clients to providing reliable and economical technology which can provide aneffective means of addressing global warming and ensuring the long term, environmentally sustainable use of

important fossil fuel reserves.

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CO2 Recovery Technology