Capture from cement and UK calcium

looping research

Dr Paul Fennell (UKCCSRC Industrial Emissions Research Area Champion) p.fennell@imperial.ac.uk Duncan Leeson (PhD student) did the actual work…

Comparison of Industrial Sectors

The four largest CO2 emitting industrial sectors make up almost 75% of industrial emissions. The sectors investigated here are iron and steel production, petroleum refining, chemical manufacturing, cement manufacture and pulp and paper production

• Chemical manufacture and petroleum

refining were joined in this study due to the similar nature of the boilers which CO2 would be captured from.

• The pulp and paper industry was also investigated due to the large potential for carbon capture in this sector

Systematic Review Process

Search

o Initial search terms were drawn together to cover the major technological areas of CCS, policy and costs

o Search terms were entered into three academic databases o Results were recorded, and search terms customised to return a selection of relevant

papers; in this case, 525.

Summarise

o All abstracts were screened and non-relevant papers were discarded according to agreed criteria

o All 262 papers deemed relevant in the initial screening were read, summarized and prioritised

o A questionnaire was formulated to allow all relevant data from the papers to be classified

Analysis

o Papers were sorted by industry and information regarding technology, policy or cost noted in questionnaire and compared where applicable

o In order to directly compare capital costs and produce meaningful cost analysis, a cost escalator model was constructed to convert all costs to 2013 US Dollars

Cost Comparisons for Industrial Plants

Iron and Steel Refineries Pulp and Paper Cement

Cost (USD 2013)

Number Cost (USD 2013)

Number Cost (USD 2013)

Number Cost (USD 2013)

Number

Post-combustion 74.23 5 77.60 5 24.73 2 106.53 3

Oxy-combustion N/A 0 65 1 N/A 0 59.46 1

Mineralisation 62.50 2 N/A 0 N/A 0 N/A 0

Calcium Looping N/A 0 51 1 N/A 0 37.78 4

Main Technological Options for Industrial Carbon Capture

Post Combustion Capture through Amine Solvents

• Amine-based solvents such as MEA and MDEA can strip CO2 from flue gases with capture efficiencies of >99%,

• This gives a waste gas stream of very high purity CO2

• Can be easily retrofitted onto existing plants

• Generally high cost of regenerating the solvents, which are often toxic and corrosive

Absorber

Stripper

Lean/Rich Heat

Exchanger

Export Gas

Reflux

Drum

Flue Gas

Inlet

Main Technological Options for Industrial Carbon Capture

Calcium Looping Technologies

• Operate by repeated reaction and regeneration of a CaCO3 to form CaO + CO2. High temperatures are needed to regenerate the CaO.

• Produces stream of pure CO2 from flue gas which can then be sequestered

• Problems with solid transport and attrition, and loss of activity of sorbent over time

Main Technological Options for Industrial Carbon Capture

Oxyfuel Combustion

• By burning fuels in pure oxygen (plus recycled CO2) instead of air, the flue gas is almost pure CO2.

• Can provide heat for boilers and furnaces, e.g. in iron and steel mills • Using a smaller volume of oxygen then air means that process

equipment can be smaller, so lower capital costs (oxyfuel in cement plant)

• Requires large, energy intensive air separation unit

Main Technological Options for Industrial Carbon Capture

Other technologies

» Mineral carbonation of waste slags forms stable carbonates on reaction with CO2, although a limited capture potential and low TRL

» Biological systems using bacteria or algae to capture CO2 are still in early development

» Membranes to directly separate CO2 from flue gases have been trialled, but little cost data for large scale use exists

» Formation of hydrate compounds on reaction with CO2 which can be filtered out of flue streams

Carbon Capture on Cement Plants

• Two major technologies costed for cement plants – amine post-combustion capture and calcium looping

• Research near-evenly split between the two technologies

• Post combustion capture has an estimated capture cost of $107 per tonne for cement plants

• Calcium looping technologies average at $38 per tonne, though are less developed

• Oxy-combustion has been investigated and estimated at an average cost of $60 per tonne.

• Health warning: • At least 50 % variation in estimated costs per technology per industry. • Academic research can be prone to making optimistic assumptions – frequently

around cost of capital

Relative Abundance of Cost Information for Industrial

Carbon Capture

Refineries

Cement Pulp &

Paper

Iron & Steel

Carbon Capture on Cement Plants

• 5% of all global CO2 emissions can be attributed to the cement manufacture process.

• Within the process, 60% of the emissions are due to the calcination reaction and the other 40% attributable to combustion for heat generation

• Hence pre-combustion can only capture a maximum of 60% of emissions, though with energy costs this is reduced to around 52%

• Impurities in the flue stream such as SO2 and dust can cause amine scrubbing units to have high heat duties and necessitate a high degree of solvent regeneration due to side reactions

Precalciner Kiln Cement Grinding

Fuel & Air Mix

CO2CO2

Fuel & Air Mix

CaCO3 Cement

Additives

Clinker

Alternatives to MEA– Oxyfuel combustion

Oxy-fuel combustion

Potential Benefits when used in cement plants……

Reduces the fuel requirements

Can remove virtually all of the CO2

Enrichment to 30-35% O2 atmosphere

can increase kiln capacity by 25-50%

Oxy-fuel process in cement plant

ECRA, 2009

1. Oxygen separation is still expensive 2. Calcination in high-CO2 atmospheres reduces the surface area of lime-may

affect the formation of calcium silicates

3. The cement plant must be airtight 4. Extensive modifications to the cooler, precalciner and preheaters are required

Effect on the properties

But still Challenges…

Potential issues with integration – trace elements

Four main phases are present in cement: • Alite • Belite • Aluminate • Ferrite

Alite most important for strength (especially in early stages) Trace elements affect the formation and stability of alite

• Trace elements absolutely vital if you want alite at room temperature! Trace elements come from raw materials, e.g. clay and lime(stone), but

also fuels in cement plant and power station Beneficial trace elements:

• B, Ba, Cd, Cu, K, La, Mg, Mn, Na, Ni, Sr, Ti, V, W, Zn, Zr Detrimental trace elements:

• As, B, Be, Cr, Cu, Sb, Sn, Sr, Ti Note some are in both lists!

Lab-scale cement production

• Lab-scale fluidised bed to produce small amounts of cycled CaO

• ‘Wet process’ used batch-wise to produce cement clinker

• Cement clinker ground and mixed with gyspum to produce cement

• Coal fed into fluidised bed in some experiments

Clinker Production

Results of trace element analysis via ICP-OES

Trace element analysis of cement made from CaO from cycling experiments using La Jagua (Glencore, Colombia) coal

Beneficial

Detrimental

Both

Current UK Academic Cement Research – CCS + Cement

UKCCSRC Phase 2 funding – Integration of Cement manufacture (and Iron and Steel) with Ca looping (Anthony, Fennell)

G8 Materials Efficiency – REO Kiln (Fennell) (oxyfuel cement production) Cemex / Grantham Institute – Ca looping cement production Edinburgh – PhD (Brandani Group – Ferrari representing) examining

Cement integration with Ca looping. Energy balances and economic analysis of oxy-fuel cement manufacture

(needs doing) Effect of high CO2 concentrations on calcination of limestone (Fennell

Group, Anthony Group, Scott / Dennis Cambridge) Effect of high CO2 concentration on kiln chemistry (Fennell Group) Centre for doctoral training – Snape (Nottingham, Midlands Energy

Consortium, Sheffield + Leeds). New call soon – scoping workshop announced. E-mail p.fennell@imperial.ac.uk

and I can put you in contact

Current UK Academic Research – Calcium Looping

Fennell Group (Imperial) – advanced and enhanced sorbents, sorbent-enhanced reforming

Anthony Group (Cranfield) – linkage with cement and iron and steel, oxy-firing with elevated O2 levels and improving the calciner.

Scott and Dennis Groups (Cambridge) – advanced, enhanced sorbents, modelling. Integration with chemical looping and fuel reforming.

Brandani Group (Maria-Chiara Ferrari) (Edinburgh) Modelling, plant integration

Dupont Group (Leeds) Sorbent-Enhanced Reforming Maroto-Valer Group (Heriot-Watt) Sorbent development

E-mail p.fennell@imperial.ac.uk and I can put you in contact

Acknowledgements

We gratefully acknowledge funding from the EPSRC / RUK energy programme under grants EP/K000446/1: UKCCSRC - The United Kingdom Carbon Capture and Storage Research Centre EP/K021710/1 – G8 Multilateral Research Programme – REO Kiln UKCCSRC Phase 2 – Advanced Sorbents for CCS via Controlled Sintering UKCCSRC Phase 2 – UK Demonstration of Enhanced Calcium Looping and First Global Demonstration of Advanced Doping Techniques Grantham Institute and Cemex for Continued support in the field of Low CO2 cement The Energy Programme is a Research Councils UK cross council initiative led by EPSRC and contributed to by ESRC, NERC, BBSRC and STFC