The implementation of the EU Emission Trading Scheme ( ETS) started on January 1(st) 2005 according to national plans for allocating emissions rights. The steel industry is one of the industrial sectors included in this scheme. The objective of this paper is to investigate and evaluate the optimum solution( s) for European steel plants to meet their emission allowance with low reduction cost. An optimization model based on a Swedish steel plant is developed and used. Three scenarios were created in the model, i. e., internal changes within the steel plant, EU ETS, and the Kyoto Protocol's clean development mechanism ( CDM). For the last scenario, China was selected as a country of the non- Annex I Party for the emission trading by CDM. The modeling results show that the studied plant will face an emission gap between allowed and calculated emissions in the near future. Compared to EU ETS, the implementation of CDM projects will make the plant reduce CO2 emissions at a lower cost. The internal changes within the plant will also play an important role for the solution of low abatement cost. The model developed could serve as a benchmark for the future emission trading simulation's purpose within the European steel industry.

To develop an equation of state with simple structure and reasonable accuracy for engineering application, Redlich-Kwong equation of state was modified for gaseous CO2 and CO2-H2O mixtures. In the new modification, parameter a of gaseous CO2 was regressed as a function of temperature and pressure from recent reliable experimental data in the range: 220-750 K and 0.1-400 MPa. Moreover, a new mixing rule was proposed for gaseous CO2-H2O mixtures. To verify the accuracy of the new modification, densities were calculated and compared with experimental data. The average error is 1.68% for gaseous CO2 and 0.93% for gaseous mixtures of CO2 and H2O. Other thermodynamic properties, such as enthalpy and heat capacities of CO2 and excess enthalpy of gaseous CO2-H2O mixtures, were also calculated; results fit experimental data well, except for the critical region.

This paper investigates overall CO2 balances of combined heat and power (CHP) plants with CO2 capture and storage (CCS) in Kraft pulp and paper mills. The CHP plants use biomass-based fuels and feature advanced gasification and combined cycle technology. Results from simple process simulations of the considered CHP plants are presented. Based on those results and taking into account the major direct and indirect changes in CO2 emissions, the study shows that implementing CCS leads to steep emission reductions. Furthermore, a preliminary cost assessment is carried out to analyse the CO2 mitigation cost and its dependence on the distance that the CO2 must be transported to injection sites.

During recent years, an increased attention has been given by industries and governments from industrialized as well as developing countries to reduce greenhouse gas (GHG) emissions through the clean development mechanism (CDM). As China has increasing demands on bioenergy and Sweden has good practices and competence in developing and utilizing bioenergy technologies, this paper studies the resulting consequence if implementing Swedish bioenergy technologies in China. The potential CO2 emission reduction from each technology in China is studied. A few priority areas for future CDM projects selection by using Swedish technologies are recommended.

Black liquor constitutes a huge energy potential. In order to improve the efficiency of a pulp mill, this study is focussed on borate autocausticizing, which has proved to work efficiently in recovery boilers. The leading idea is to complete an overloaded recovery boiler with a booster gasifier. In this configuration, the black liquor is gasified with air at low overpressure. Results regarding conventional black liquor gasification are close to the reality and very promising. Regarding black liquor gasification with borate, lack of data for orthoborate, like the Gibbs free energy, did not enable good results. The model so far is a good starting point for black liquor gasification studies, and needs to be improved as soon as new data on borates will be available

In chemical looping combustion (CLC), a solid oxygen carrier circulates between two fluidised bed reactors and transports oxygen from the combustion air to the fuel; thus, the fuel is not mixed with air and an inherent CO2 separation occurs. In this paper, CLC is integrated in a natural gas fired combined cycle (NGCC). In this system, nickel- and iron-based oxygen carriers are compared regarding the system's electrical and exergy efficiencies. Furthermore, the feasibility of CLC in two interconnected pressurised fluidised bed reactors (IPFBR) is studied for both oxygen carriers. The hypothetical layout plus dimensions of the IPFBR is presented for a capacity of 800 MW input of natural gas. Finally, top-firing is proposed as an option to overcome the apparent limitation in operating temperature of the reactor equipment and/or the oxygen carriers. The results indicate that there is no significant difference in the system's efficiency if both oxygen carriers could operate at the same temperature. However, CLC seems easier to be technically realised in an IPFBR with a nickel-based oxygen carrier

Wood pellets are regarded as one of the substitutes for fossil fuels like coal and oil for heating and co-generation. Wood pellets are a successful example of market penetration of renewable energy in some countries in Europe, e.g., Sweden. An analysis process is proposed in this paper and used to conduct a techno-economic assessment of wood pellets production and applications in some areas in China with the consideration of technology transfer from Sweden by examining their market competitiveness with coal in these areas. Financial indices such as net present value (NPV), internal return rate (IRR) and year-to-positive cash flow are calculated to investigate the profitability of the technology transfer. Four locations of applications in China have been considered as case studies. The result indicates that in the market-only-based scenario, wood pellets production will not be profitable in all selected areas. New scenarios from the analysis process show that reducing investment and increasing the amount of bank loan will be helpful to increase the project's profitability in general; adding taxes on coal could be effective, but it depends on Chinese government's future efforts on climate change mitigation; carbon credits on wood pellets through the clean development mechanism (CDM) might make wood pellet projects profitable giving wood pellets a nich-market. The potential global environment benefits of CO2 emission reduction by using wood pellets to replace coal in a 7 MWth coal-fired industrial boiler with a thermal efficiency of 80% and 5000 hours of operation time are also presented.