Carbon Capture and Storage (CCS) is commonly recognised as a prospective technology that could be used in the fight to cut carbon dioxide emissions. By “capturing” carbon dioxide (either before or after burning) and transporting it to locations in which it can be stored suitably, under geological formations, the idea is simply that it will reduce the amount of carbon dioxide found in ambient air. With government support in April 2009, a policy was introduced that required all fossil fuel power stations to be “carbon capture ready”, fitted with CSS technology that would enable it to be retrofitted at a later date [1]. Furthermore, in May 2010, under the coalition, support of an additional programme was put into place that would allow 4 commercial scale CSS demonstration plants to be built between the years 2010-2020 [2] . Deployment of these plants would occur from 2020 onwards. According to the European Commission, the aim is to make zero emission power generation using CSS technology commercially feasible by 2020 [3].
New Directions
Yet, as highlighted by Woodman-Hardy [1], there are many issues and debates surrounding the sustainability of CCS technology. The most prominent of these issues is that CSS is a finite solution, offering only a quick fix. As stated by Ron Zevenhoven, a professor in Thermodynamics and Modelling (Akademi University, Finland), “ large scale capture and the development of technologies for capturing and transporting does not make sense if long-term storage capacity for carbon dioxide does not exist, or is not developed at the same time [4] .” Therefore, if this is the case, what if we could utilise carbon dioxide as a raw material instead of removing it as a waste? Carbon Capture and Utilisation (CCU) has turned into new avenue for research and development.
Carbon Capture and Utilisation
Carbon Capture and Utilisation (CCU) is being turned to as a half-way point been carbon mitigation as well as a raw material for industrial processes. After all, in today’s society, despite recent advancements in electric car technology and green energy for example, we still rely heavily on fossil fuels to provide the majority of our fuel demands. So, if energy and money is being inputted in order to meet these demands, why don’t we try to utilise our waste as well? This is where CCU technologies and developments have come into the fore, and at present intense debate has occurred. This article will attempt to highlight the most prominent and most anticipated developments into CCU processes.
Production of Plastics
German chemical and pharmaceutical giant, Bayer, earlier this year were cast under the media spotlight when scientists of their organisation managed to discover a suitable catalyst for effective and efficient utilisation of carbon dioxide into polyurethane. The innovative production process is known as, the “Dream Production” project. For this, discovery of a suitable catalyst was critical for development as previously it was not available for the last four decades [5] . As a result of its discovery, a pilot plant for polyurethane was soon built and production started in February, 2011.
Polyurethane is a polymer; it can be used to construct many products that you may already be utilising today. For example [6]:
- Insulation for refrigerators and freezers
- Building Insulation
- Furniture Cushioning
- Mattresses
- Car Parts
- Coatings
- Adhesives
- Rollers And Tyres
- Composite Wood Panels
- Shoe Soles
- Sportswear
Carbon Capture for Biological Processes
Greenhouse Gases
Transporting exhaust carbon dioxide gases from gas burners for example (or nearby power stations and chemical plants, if present), into greenhouses is becoming standard practice. As carbon dioxide is utilised for photosynthesis and growth, it allows for the increased production of numerous plants, vegetables and fruits. Typically, green houses now operate at concentration ranges of 1,300 – 1,500 ppm [4] . Ambient air on the other hand currently only has carbon dioxide concentrations of 386 ppm [4]. Despite progress, more research is currently underway to discover the response field crops would yield against this process [4].
Algae
Algae have many advantages which have allowed for its increase in cultivation around the world. For example, they have a high biodiversity and high productivity per unit area. In comparison, maize produces 7 – 18 tons per hectare while algae can produce up to 230 – 350 tons per hectare [4]. Yet, one of the most useful properties algae has when it comes to CCU is that firstly, it is able to absorb carbon dioxide (like most plants), and secondly, it has the added benefit of being harnessed in bio fuel production. It has the potential to yield much higher volumes of bio fuel per acre of production than many other bio fuel sources [7] . In this field, the most notable commercial developments have been occurring with ExxonMobil and Synthetic Genomics.
|
Bio Fuel Sources |
Gallons of fuel per acre |
| Algae | 2000 |
| Palm | 650 |
| Sugar Cane | 450 |
| Corn | 250 |
| Soy | 50 |
Table to show the approximate yields of a variety of bio fuel sources [7].
Carbon Mineralisation (Also known as Mineral Carbonation)
Carbon mineralisation is a complex process. In a nutshell, carbon mineralisation is the process of turning carbon dioxide into a “solid”. By reacting carbon dioxide to silicate rocks, such as magnesium or calcium silicates (naturally found on earth) or by reacting it to industrial waste materials such as steel slag, fly ash etc. The result is that numerous products can be made while changing the form of carbon from carbon dioxide, into a more permanent form.
Products of this process include:
- Magnesium Bicarbonate: Can be used to buffer changes in sea water pH [4].
- Calcium Carbonate: a white powder used for paper products [4].
- Iron Oxide: Can be produced as a by product. Can be used to make steel. Waste slag from the steel making process can be carbonated (reacted with carbon dioxide) once again to produce another calcium carbonate (known as, precipitated calcium carbonate), for use in paper making again [4]!
- Slurry: A waste product that can be used for land expansion [8].
- Filler in concrete [8].
- Bitumen: A sticky, black liquid, used to make roads [8].
Carbon mineralisation is a potential technology option that could be used simultaneously for, mitigation against carbon dioxide, and reducing the effects of global warming by using mineralisation products itself to build dykes, create water buffers or for land reclamation [8]. Another commercial key player in this field that you may recognise is Shell [8]
Alternative Fuels
Sunshine to Petrol Fuel
Sandia National Laboratories are attempting to make liquid fuel from combining sunlight, carbon dioxide and water [9]. The device in which these reactions will be taking place is known as, the Counter Rotating Ring Receiver Reactor Recuperator (or simply, CR5). In order to utilise existing engine infrastructure, Sandia National are attempting to reverse internal combustion. The process occurs when enough hydrogen and carbon atoms are bonded together; it is then heavy enough to exist at liquid room temperature. The result is a fuel which is similar to natural gas (known as Syngas), with a few more chemical steps, methanol and other liquid fuels are produced which can be utilised in engines designed for petrol.
The Finish Line
The problem with many of these processes is sometimes one and the same:
- Cheaper options may exist elsewhere: For instance, retaining CCS technology in some cases or simply allowing emissions to continue until further technological progress is made.
- Lack of Funding: Consensus exists in which a call for pooled resources is needed, or better integration, to ensure that developments are not divided into SMEs for example, and national backed initiatives [4]. For often, SMEs will have to find their own funding in order to fund research and development. As a result, they may simply not participate at all.
- Lack of Publicity: Increased publicity will help spur debate. For instance, it is only recently that some industries are starting to wake up and react [4].
[1] http://www.energysavingwarehouse.co.uk/news/126/20/Carbon-Capture-Storage-Issues-and-Debates.html
[2] http://www.environment-agency.gov.uk/research/library/position/120154.aspx
[3] http://ec.europa.eu/energy/coal/sustainable_coal/ccs_en.htm
[4] http://www.fona.de/CO2-seminar/co2_bmbf.pdf
[5] http://www.press.bayer.com/baynews/baynews.nsf/id/F7D95A62E946F894C125783A002F2CB5
[6] http://www.polyurethanes.org/index.php?page=what-is-it
[7] http://www.exxonmobil.com/Corporate/energy_vehicle_algae.aspx
[8] Verduyn, M., Geerlings, H., Mossel, G. van, Vijayakumari, S., 2011. Review of the various CO2 mineralization product forms. Energy Procedia 4, 2885-2892. Available At: http://www.sciencedirect.com/science/article/pii/S1876610211003924
