Cement Energy and Environment

Capturing, storing, and utilising carbon is inevitable Capturing carbon from cement kiln flue gas is technically feasible, as several research projects have already shown. For downstream processing there are two main options available storage/sequestration (CCS) or utilisation (CCU). Heidelberg Cement considers CCS inevitable to reach the worldwide targets as defined in the cement technology roadmap published in 2009. The technology is in principle ready to be applied, but it is currently not economically fElasible, as sufficient regulatory frameworks are la:king (e.g. EU CCS Directive), public support h; weak in several countries, and carbon prices are~ too low to incentivise investment. In cases where C02 injection is supporting the extraction of oil or gas, CCS is today already commercially viable and one can see large scale applications such as the Boundary Dam project operated by SaskPower in Saskatchewan Canada. While in Scandinavia and Canada CCS is generally accepted, in the UK it is not yet at that stage. In the European mainland countries, such as Germany, the public acceptance of underground storage is currently lacking, though offshore storage seems to be more accepted, but possibilities for developing storage facilities are quite limited. While CCS offers the potential to deal with C02 in volumes of millions of t per year, CCU– applications focus on smaller volumes in the range of 10 000 or 100 000 tpy. Some applications are already commercially applied today others will follow soon, more or less independent from current low C02 prices. The limiting factors for CCU– applications are, besides economic parameters , land and water availability or the size · of downstream markets. It is clear that both CCS and CCU need to be developed in parallel as a whole range of solutions will have to be implemented by 2050. It is also clear that CCS will be the major technology to achieve decarbonisation of the cement sector in the long-term, while CCU is a commercially viable solution to reduce emissions significantly in the meantime. Courtesy: Worldcement.com, from internet TACKLING THE CLIMATE CHALLENGE -PART TWO Learning from the power sector: Carbon capture and Oxyfuel CCS and most of the CCU-technologies require C02 to be concentrated to a high level, or at least to a level that C02 can be reasonably liquefied. Therefore the primary objective of the cement industry is to develop either a process integrated technology or end-of-pipe solution to increase the C02 concentration from roughly 25% for a conventional kiln to at least 75%, preferably higher than 90% purity. In 2014, Heidelberg Cement started the first industrial flue-gas carbon capture project in the industry at the Norcem cement plant in Brevik , Norway, in close cooperation with ECRA. 75% of the €12 million project is funded by the Norwegian government through the Climit program of Gassnova. The intermediate results of these tests were so positive that a feasibility study for a full– scale application has been launched. As Carbon Capture is capital intensive and requires significant operational costs, ECRA has analysed to what extent the operation of a kiln in 'oxyfuel'-mode would reduce these costs. The principle of an oxyfuel kiln is that calcination of limestone takes place in a pure oxygen atmosphere and the exhaust gas is recirculated to the clinker cooler. In order to have enough oxygen in the main burner, pure oxygen is added to the cooler as well. By such an operation, the C02 content after the preheater can be increased to more than 70%. In the so-called CEMCAP program, funded by the Horizon 2020 program of the EU, several critical components will be tested for an oxyfuel operation mode. Heidelberg Cement is facilitating the construction and testing of a demo clinker cooler under simulated oxyfuel conditions at its Hannover works . Calix: a process C02 separation technology for the cement industry While Carbon Capture and Oxyfuel are developments originating from the power sector and are converted for use in a cement kiln, Heidelberg Cement is exploring other innovations that are cement-kiln specific. The technology provider Calix commercially operates an indirectly heated calciner for the production of magnesium oxide in Australia. The calcination of limestone 66