http://hdl.handle.net/2282/145 Search the Channel search http://teora.hit.no:8443/dspace/simple-search http://hdl.handle.net/2282/440 Title: Carbon dioxide emission reduction by increased utilization of waste-derived fuels in the cement industry <br/> <br/>Authors: Tokheim, Lars-André; Brevik, Per <br/> <br/>Abstract: Considerable reductions in Norway's emissions of greenhouse gases like CO2 are required to meet the commitments of the Kyoto Protocol. CO2 emissions from cement clinker production originate from decarbonation of limestone as well as fuel combustion, and the cement plants in Norway have to comply with requirements given by the pollution control authorities via the national emissions trading system. There are several ways of reducing CO2 emissions from the cement industry. Utilizing CO2- neutral waste fuels as a replacement for fossil fuels is an attractive means of reducing the net CO2 emissions. Using modern kiln technology is another important measure facilitating lower emissions. The Norcem plant in Brevik carried out an extensive modernization project in 2004-5, and as a result of this the plant in Brevik currently uses close to 100,000 tons of CO2-neutral wastefuels every year. The outcome of this is a reduction in fuel-generated CO2 emissions of about 25 % from 1995 to 2005. Reduction of CO2 emissions by secondary methods such as post-combustion measures using amine absorption for the capture of CO2 in the exhaust gas from the cement plant is technically feasible, but expensive and risky. Sun, 29 Oct 2006 22:58:59 GMT http://hdl.handle.net/2282/436 Title: Assessment of mercury emission at Norcem's cement kiln by use of 203 Hg tracer <br/> <br/>Authors: Eriksen, Dag Øistein; Tokheim, Lars-André; Eriksen, T.A.; Meyer, Julien; Qvenild, Carsten <br/> <br/>Abstract: In manufacture of cement clinker, mercury is introduced in the cement kiln system via the fuels and as constituents in the raw materials, i.e., limestone, iron ore, etc. The permissible emission of Hg to air is very low (0.05 mg/Nm3) due to its toxicity. Thus, it is important to know how mercury distributes and behaves in the kiln system. The objective of the study was to measure the distribution of mercury in the kiln system, to measure the hold up time of Hg, to measure the portion of emission through the chimneys, and to see the dependence of the injection sites on these parameters. The results showed that the amounts of mercury being emitted through the exhaust gases were largely dependent on where it was injected. The residence time of mercury in the system was nevertheless long, after 10 hours it was still increase in the count rate of the mercury absorbed. There was also an immediate increase in the filter dust, but nothing could be measured in the clinker. This knowledge is needed for the reduction of mercury emissions. <br/> <br/>Description: The original publication is available at www.springerlink.com Sun, 29 Oct 2006 22:58:59 GMT http://hdl.handle.net/2282/399 Title: Modified Smith-predictor multirate control utilizing secondary process measurements <br/> <br/>Authors: Ergon, Rolf <br/> <br/>Abstract: The Smith-predictor is a well-known control structure for industrial time delay systems, where the basic idea is to estimate the non-delayed process output by use of a process model, and to use this estimate in an inner feedback control loop combined with an outer feedback loop based on the delayed estimation error. The model used may be either mechanistic or identified from input-output data. The paper discusses improvements of the Smith-predictor for systems where also secondary process measurements without time delay are available as a basis for the primary output estimation. The estimator may then be identified also in the common case with primary outputs sampled at a lower rate than the secondary outputs. A simulation example demonstrates the feasibility and advantages of the suggested control structure. Sun, 29 Oct 2006 22:58:59 GMT http://hdl.handle.net/2282/398 Title: A didactically motivated PLS prediction algorithm <br/> <br/>Authors: Ergon, Rolf; Esbensen, Kim H. <br/> <br/>Abstract: The intention of this paper is to develop an easily understood PLS prediction algorithm, especially for the control community. The algorithm is based on an explicit latent variables model, and is otherwise a combination of the previously published Martens and Helland algorithms. A didactic connection to Kalman filtering theory is provided for a methodological overview. Sun, 29 Oct 2000 22:58:59 GMT