One highlight from the cement industry news over the last month was Skyonic's announcement that it has opened a commercial-scale carbon capture unit at the Capitol Aggregates cement plant in Texas, US. Details were light, but the press release promised that the unit was expected to generate US$48m/yr in revenue for an outlay of US$125m. Potentially, the implications for the process are profound, so it is worth considering some of the issues here.
Firstly, it is unclear from the public information released whether the process will actually make a profit. The revenue figures for the Skyonic unit are predictions and are dependent on the markets that the products (sodium biocarbonate, hydrogen and chlorine) will be sold into. Skyonic CEO and founder, Joe Jones, has said in interview that the sodium-based product market by itself could only support 200 - 250 plants worldwide using this process. Worldwide there are over 2000 integrated cement plants. Since Jones is selling his technology his market prediction might well be optimistic. It is also uncertain how existing sodium biocarbonate producers will react to this new source of competition.
Secondly, Skyonic is hoping to push the cost of carbon capture down to US$20/t. Carbon dioxide (CO2) capture and transportation varies between industries depending on the purity and concentration of the by-product. For example, in 2011 the US Energy Information Administration estimated the cost for CO2 capture to range from US$36.10/t for coal and biomass-to-liquids conversion up to US$81.08/t for cement plants. The difference being that capturing CO2 from cement plant flue gas emissions requires more cleaning or scrubbing of other unwanted chemicals such as mercury.
With these limitations in mind, Skyonic is placing itself in competition with the existing flue gas scrubbing market rather than the carbon capture market, since the level of CO2 removal can be scaled to local legislation. Plus, SOx, NO2, mercury and other heavy metals can be removed in the process.
Back on carbon capture, Skyonic is securing finance for a process it calls Skycycle, which will produce calcium-based products from CO2, with a pilot plant planned at Capitol Aggregates for late 2015. This puts Skyonic back amongst several other pilot projects that are running around the world.
Taiwan Cement and the Industrial Technology Research Institute inaugurated their calcium looping project pilot in mid-2013. It was last reported to have a CO2 capture rate of 1t/hr.
The Norcem cement plant in Brevik, Norway started in early 2014 to test and compare four different types of post-combustion carbon capture technologies at its pilot unit. These are Aker Solutions Amine Technology, RTI Solid Sorbent Technology, DNV GL/ NTNU/ Yodfat Engineers Membrane Technology and Alstom Power Regenerative Calcium Cycle. The project in conjunction with HeidelbergCement and the European Cement Research Academy (ECRA) is scheduled to run until 2017.
St Marys Cement in St Marys, Canada started its bioreactor pilot project in July 2014. This process uses flue gas to grow algae that can then be used for bio-oil, food, fertiliser and sewage treatment.
If Skyonic is correct then its sodium biocarbonate process in Texas is a strong step towards cutting CO2 emissions in the cement industry. Unfortunately, it looks like it can only be a step since the market won't support large-scale adoption of this technology. Other pilots are in progress but they are unlikely to gather momentum until legislation forces cement producers to adopt these technologies or someone devises a method that pays for the capture cost.
