the integration of novel lithium-based sorbents into natural gas combined cycle … › globalassets...

The integration of novel lithium-based

sorbents into Natural Gas Combined

Cycle power plants for the purpose of

𝐶𝑂2 capture

Ahmed Saleh

PhD researcher

E. Sanchez Fernandez, Susana Garcia,

Mercedes Maroto-Valer,

CICCS group, Heriot-Watt University

Aim and objectives

Investigate the process integration of high temperature lithium silicate based sorbents

into power plants for 𝐶𝑂2 capture.

14/06/2017 2

Contents

• Lithium orthosilicate as novel sorbents

• Integration of 𝐿𝑖4𝑆𝑖𝑂4/𝐿𝑖2𝐶𝑂3 Looping system

into Power plants

• Cases description and modelling approach

• Results & Discussion

• Conclusions and Future Work

14/06/2017 3

Lithium Silicate as a good candidate for

High temperature 𝑪𝑶𝟐 capture

14/06/2017 4

Effect of increasing CO2 concentration on capture capacity of Li4SiO4 at 1 atm and T=550C [2]

1. Quinn, R., et al.. Industrial & Engineering Chemistry Research, 2012. 51(27): p. 9320-9327. 2. Pacciani, R., et al, Environmental science & technology, 2011. 45(16): p. 7083-7088.

Cyclic CO2 capacity normalized to the 1st cycle capacity for LS 5 mm (squares) at 550 °C (humidified 14.7% CO2 in N2 feed, and CaO powder (circles) at 750 °C (dry 100% CO2). First cycle capacities: LS 5 mm, 15.3 wt %; CaO, 39 wt%.[1]

Lithium Silicate Advantages:

• Ability to work at high temperatures ( flue gas conditions )

• Good 𝐶𝑂2 capture capacity

• Higher stability over long cycles compared to CaO based sorbents

• Lower regeneration temperatures compared to CaO based sorbents

Lithium orthosilicate has lower regeneration temperature, lower regeneration heat and higher durability

𝐿𝑖4𝑆𝑖𝑂4 + 𝐶𝑂2 → 𝐿𝑖2𝐶𝑂3 + 𝐿𝑖2𝑆𝑖𝑂3

Integration of Sorbent Looping systems

into power plants

14/06/2017 5

C-1 C-2

E-2

E-4

E-1Flue gas

T1

Tabs

E-3Primary heat

recovery system

Treg

2nd / additional heat recovery

system

Air Separation Unit

Make-up

Fuel

Spent sorbent

T3T2

Air

E-5 E-6

E-7

Smart designed looping systems with several heat integration locations could save more energy and reduce the capture associated penalties

Generic scheme for HTCC plant with sorbent looping and possible heat recovery options.

Maximize the heat integration to reduce the energy penalty

Several locations for heat integration

Flexibility to integrate the capture unit on several power plants such as NGCC Plant

For lithium based sorbents, no recuperation and no make up flow was assumed

Optional

Cases description and modelling

approach

Case 1

• Based on base case model with

HTCC integrated

• Secondary HRSG /steam turbine

• ASU with 200 kwh/tO2

• 4 stage supercritical

𝐶𝑂2compression train with 30C

intercooling

Case 2

• Similar to case 1 but with low

ancillary consumption

• Lower ASU power consumption

159 kwh/tO2

• The compressors intercooling

temperature was lowered to 20C

using sea water cooling system

• CO2 is transported in liquid phase

14/06/2017 6 3. Franco, F., et al.,. European Benchmarking Task Force, 2011.

• The modelling basis and assumptions for the NGCC power plant are as per European Benchmarking Task Force (EBTF) common frame work [3]

• The NGCC plant was modelled using Aspen Plus software steady state with and without capture to evaluate efficiency, power and electrical penalties associated with carbon capture

Base Case ( NGCC Plant without capture)

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2 x F-Class GT

2 x 3 pressure level HRSG

IP reheat

K-1 K-2

E-1

E-2

K-3

H-1

HPS-3 IPS-1 HPS-2 IPS-2 HPS-1 HPB-1 HPE-2 LPS-1 IPS-3 HPE-1 IPB-1 IPE-1 LPB-1 LPE-1

K-4

V-1

E-3

V-2

E-4

H-2

V-3E-5

H-3

E-6

G-1

~

CW-1

CW-2V-4

V-5

To stack

D-1

K-5

V-7V-8

To 2nd gas turbine train

V-9

To 2nd gas turbine train

V-10

From 2nd HRSG train

V-11

From 2nd HRSG train

V-12

From 2nd HRSG train

Natural Gas

Air

Fuel preheating

1 unit x 3 pressure level steam turbine

14/06/2017 8

K-1 K-2

E-1

E-12Natural gas

K-3

H-4

Air


K-4

V-16

E-3

V-15

E-4

H-5

V-14E-5

H-6

E-7

G-1

~

CW-3

CW-4V-13

V-12

To stack

D-2

K-5

V-10V-9

V-8

V-7

V-6 V-5

C-1 C-2

HPB-2

HPS-4 E-8

V-4

V-3

K-6 K-7

G-2

K-8

ASU

E-9CW-5

CW-6

IPS-4 HPS-5 IPS-5 HPE-3

H-7CW-7

CW-8To CO2 compression

Oxygen

~

From 2nd primary HRSG From 2nd primary HRSGFrom 2nd primary HRSG

Fuel

E-10

HPE-4

E-11

To 2nd gas turbine

V-1

To 2nd gas turbine

Flue gasHP steam / waterIP steam / waterLP steam / waterCO2 stream

P-1

K-1 K-2

E-1

E-12Natural gas

K-3

H-4

Air


K-4

V-16

E-3

V-15

E-4

H-5

V-14E-5

H-6

E-7

G-1

~

CW-3

CW-4V-13

V-12

To stack

D-2

K-5

V-10V-9

V-8

V-7

V-6 V-5

C-1 C-2

HPB-2

HPS-4 E-8

V-4

V-3

K-6 K-7

G-2

K-8

ASU

E-9CW-5

CW-6


H-7CW-7


Oxygen

~


Fuel

E-10

HPE-4

E-11

To 2nd gas turbine

V-1

To 2nd gas turbine


P-1

K-1 K-2

E-1

E-12Natural gas

K-3

H-4

Air


K-4

V-16

E-3

V-15

E-4

H-5

V-14E-5

H-6

E-7

G-1

~

CW-3

CW-4V-13

V-12

To stack

D-2

K-5

V-10V-9

V-8

V-7

V-6 V-5

C-1 C-2

HPB-2

HPS-4 E-8

V-4

V-3

K-6 K-7

G-2

K-8

ASU

E-9CW-5

CW-6


H-7CW-7


Oxygen

~


Fuel

E-10

HPE-4

E-11

To 2nd gas turbine

V-1

To 2nd gas turbine


P-1

K-1 K-2

E-1

E-12Natural gas

K-3

H-4

Air


K-4

V-16

E-3

V-15

E-4

H-5

V-14E-5

H-6

E-7

G-1

~

CW-3

CW-4V-13

V-12

To stack

D-2

K-5

V-10V-9

V-8

V-7

V-6 V-5

C-1 C-2

HPB-2

HPS-4 E-8

V-4

V-3

K-6 K-7

G-2

K-8

ASU

E-9CW-5

CW-6


H-7CW-7


Oxygen

~


Fuel

E-10

HPE-4

E-11

To 2nd gas turbine

V-1

To 2nd gas turbine


P-1

NGCC Plant Case with HTCC plant (Case 1)

Stochiometric Reactor, 𝑇𝑎𝑏𝑠= 500C, Fractional conversion = 0.54, 90% 𝐶𝑂2 capture

Gibbs Reactor, 100% sorbent regeneration, 𝑇𝑑𝑒𝑠 > 690C (695 to 720 C), no make up flow

100 % solid separation

4 stage compression train, 110 bar, 30C intercooling

35% O2 stream with 3% excess oxygen

200 kwh/t𝑂2

CO2 recycle O2 / fuel heaters

Exothermic Heat recovery No heat recuperation

14/06/2017 9

Results &

Discussion

Specific energy demand for the HTCC

plant as a function of regeneration

temperature (Treg)

14/06/2017 10

Increasing the regeneration temperature leads to linear increase in the energy demand

The impact of the HTCC plant on power

plant performance

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Increasing 𝑇𝑟𝑒𝑔 does not have a significant impact on plant efficiency and

electricity penalty

a) Net power plant efficiency b) SPECCA and EOP

Simulation results for 𝑻𝒓𝒆𝒈 = 𝟕𝟏𝟎𝑪 –

secondary HRSG

14/06/2017 12

K-1 K-2

E-1

E-12Natural gas

K-3

H-4

Air


K-4

V-16

E-3

V-15

E-4

H-5

V-14E-5

H-6

E-7

G-1

~

CW-3

CW-4V-13

V-12

To stack

D-2

K-5

V-10V-9

V-8

V-7

V-6 V-5

C-1 C-2

HPB-2

HPS-4 E-8

V-4

V-3

K-6 K-7

G-2

K-8

ASU

E-9CW-5

CW-6


H-7CW-7


Oxygen

~


Fuel

E-10

HPE-4

E-11

To 2nd gas turbine

V-1

To 2nd gas turbine


P-1

Simulation results for 𝑻𝒓𝒆𝒈 = 𝟕𝟏𝟎𝑪 –

secondary HRSG TQ curve

14/06/2017 13

Fixed HP / Low pressure - slight increase in reheat pressure from 31.7 bar to 33.0 bar to ensure suitable temperature available at lower end of secondary HRSG. Hot CO2 ( 321 - 361C) is used to preheat fuel / oxygen.

Summary of simulation results for base

case (NGCC plant without capture) and

Cases 1 and 2 (𝑻𝒂𝒃𝒔 = 𝟓𝟎𝟎𝑪, 𝑻𝒓𝒆𝒈 = 710C)

14/06/2017 14

Parameter Unit

NGCC

without

capture

NGCC with capture

Case 1 Case 2

Gross power output MW 837.3 1038.3 1038.6

Gas turbine output (x1) MW 274.6 274.6 274.6

Primary Steam turbine output MW 288.1 287.7 287.7

Secondary steam turbine power output MW NA 201.4 201.8

Net power output MW 829.9 953.1 961.4

Fuel thermal Input MWth(LHV) 1423.0 1864.8 1865.9

Net Plant efficiency %LHV 58.3 51.1 51.5

CO2 emissions kg/MWh 351.6 32.3 32.0

Penalty points % NA 7.2 6.8

SPECCA GJ/tCO2 NA 2.7 2.6

Case 2 achieved higher efficiency (6.8 penalty points) and lower SPECCA due to lower ancillary consumption

Parameter Unit

NGCC

without

capture

NGCC with capture

Case 1 Case 2











Parameter Unit

NGCC

without

capture

NGCC with capture

Case 1 Case 2











Impact to power plant

14/06/2017 15

a) TQ curve for primary HRSG for NGCC plant base case without capture.

b) TQ curve for primary HRSG for NGCC plant base case with capture unit integrated (Case 1).

Slight increase in the flue gas TQ line slope. No major change in primary HRSG

Comparison to other technologies

14/06/2017 16

Parameter Unit

Base

case MEA CESAR-1 CaCO3 Li4SiO4

Reference [-] (Sanchez Fernandez et al., 2013)

(Berstad

et al.,

2012)

This

work

Wgross (calc) MW 837.3 759.9 770.7 627.6 1038.6

Wnet (calc) MW 829.9 709.9 722.6 559.7 961.4

Net Plant efficiency %LHV 58.3 49.9 50.8 45.6 51.5

CO2 emissions kg/MWh 351.6 41.1 40.4 30.6 32.0

Penalty points % 8.4 7.6 12.74 6.80

SPECCA GJ/tCO2 3.4 2.9 5.4 2.6

EOP kWh/tCO2 456.9 408.6 659.7 340.1

Lithium silicate achieved better efficiency compared bench mark amine solvent and basic CaO sorbent

Parameter Unit

Base



(Berstad

et al.,

2012)

This

work

Wgross (calc) MW 837.3 759.9 770.7 627.6 1038.6

Wnet (calc) MW 829.9 709.9 722.6 559.7 961.4



Penalty points % 8.4 7.6 12.74 6.80

SPECCA GJ/tCO2 3.4 2.9 5.4 2.6

EOP kWh/tCO2 456.9 408.6 659.7 340.1

Parameter Unit

Base



(Berstad

et al.,

2012)

This

work

Wgross (calc) MW 837.3 759.9 770.7 627.6 1038.6

Wnet (calc) MW 829.9 709.9 722.6 559.7 961.4



Penalty points % 8.4 7.6 12.74 6.80

SPECCA GJ/tCO2 3.4 2.9 5.4 2.6

EOP kWh/tCO2 456.9 408.6 659.7 340.1

Conclusion and future recommendations

14/06/2017 17

. .

First process integration study of lithium-based sorbents for high temperature 𝐶𝑂2 capture applications into NGCC plants.

Lithium silicate integration achieved better overall plant

efficiency and lower electricity output penalty compared to basic, advanced amines and basic CaO sorbents.

No significant change in efficiency when 𝑻𝒓𝒆𝒈 changes. Future

work should focus on optimizing the integration within the studied range of 𝑇𝑟𝑒𝑔.

Indirect heating options can be investigated as a replacement

for oxyfuel combustion.

14/06/2017 18

Thank you

Supplementary Info

14/06/2017 19

Equilibrium Thermodynamics vs kinetics

14/06/2017 20

𝑇𝑎𝑏𝑠=500C, 𝑇𝑟𝑒𝑔 > 690C

Fractional Conversion = 0.54

3. Essaki, K., M. Kato, and H. Uemoto, Influence of temperature and CO2 concentration on the CO2 absorption properties of lithium silicate pellets. Journal of Materials Science, 2005. 40(18): p. 5017-5019.

Equilibrium CO2 partial pressure vs. turnover temperature (T0) for Li4SiO4 estimated with the software Aspen Plus®.

Li4SiO4 fractional conversion curve for 5% vol CO2 and 500ºC. Calculated from [3]


approach

14/06/2017 21

NGCC Plant Case with HTCC plant (CASE 1)

• Extracted CO2 stream is compressed to 110 bar before transportation using multi stage supercritical compression train with 30C intercooling system


approach

14/06/2017 22

Plant efficiency measurement

• Net Plant efficiency 𝜂 =W1+W2

𝑚1+𝑚2 ∙∆𝐻𝑐

• Specific Primary Energy consumption for CO2 avoided (SPECCA) in GJ/tCO2 [8]:

𝑆𝑃𝐸𝐶𝐶𝐴 =𝐻𝑅𝐶𝐶−𝐻𝑅𝑅𝐸𝐹

𝐸𝑅𝐸𝐹−𝐸𝐶𝐶=

3600 .(1

ƞ𝐶𝐶−

1

ƞ𝑅𝐸𝐹)

𝐸𝑅𝐸𝐹−𝐸𝐶𝐶 =

3600 .(1

ƞ𝐶𝐶−

1

ƞ𝑅𝐸𝐹)

𝐸𝑅𝐸𝐹−𝐸𝐶𝐶

Where 𝐻𝑅𝐶𝐶 and 𝐻𝑅𝑅𝐸𝐹 are the heat rate (KJ/Kwhe) for the Plant with capture unit and before adding capture unit respectively, 𝐸𝐶𝐶 and 𝐸𝑅𝐸𝐹 are CO2 emission rate in (KgCO2/Kwhe) for the Plant with capture unit and before adding capture unit respectively • Electricity output penalty (EOP) [13]: • the total net loss in plant power output after integration of the co2 capture uni

𝐸𝑂𝑃= 𝑃𝑙𝑎𝑛𝑡 𝑃𝑜𝑤𝑒𝑟 𝑂𝑢𝑡𝑝𝑢𝑡 𝑏𝑒𝑓𝑜𝑟𝑒 𝑐𝑎𝑝𝑡𝑢𝑟𝑒 𝐾𝑊 −𝑃𝑙𝑎𝑛𝑡 𝑃𝑜𝑤𝑒𝑟 𝑂𝑢𝑡𝑝𝑢𝑡 𝑎𝑓𝑡𝑒𝑟 𝑐𝑎𝑝𝑡𝑢𝑟𝑒 (𝐾𝑊)

𝐶𝑂2 𝑐𝑎𝑝𝑡𝑢𝑟𝑒𝑑(𝑇𝑜𝑛𝑒/𝑕𝑜𝑢𝑟)

• Marginal thermal efficiency of the oxyfuel regenerator [9] to measure the thermal efficiency of the additional natural gas combustion :

𝜂𝑚𝑎𝑟𝑔 =𝑊2

𝑚2∙∆𝐻𝑐+Δ𝐻𝑟

8. Lucquiaud, M. and J. Gibbins, On the integration of CO 2 capture with coal-fired power plants: a methodology to assess and optimise solvent-based post-combustion capture systems. Chemical Engineering Research and Design, 2011. 89(9): p. 1553-1571.

9. Díaz, A.G., et al., Sequential supplementary firing in natural gas combined cycle with carbon capture: A technology option for Mexico for low-carbon electricity generation and CO 2 enhanced oil recovery. International Journal of Greenhouse Gas Control, 2016. 51: p. 330-345.

.

Results Discussion

14/06/2017 23

Enthalpy-entropy diagram for the secondary HRSG for different regeneration temperatures

. .

marginal efficiency of the

secondary HRSG

14/06/2017 24

24.0

24.5

25.0

25.5

26.0

26.5

27.0

690 695 700 705 710 715 720 725

hm

arg [

%L

HV

]

Treg [ºC]

b)

14/06/2017 25

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