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Abstract: Modern cement plants have high energy efficiencies and the scope to reduce CO2 emissions by further efficiency improvements is small. One of the few ways of greatly reducing CO2 production from cement production is CO2 capture and storage (CCS). This paper summarises a study which assessed the technologies that could be used for CO2 capture in cement plants, their costs, and barriers to their use. The work covered new-build cement plants with post-combustion and oxy-combustion CO2 capture. The basis of the study was a 5-stage preheater with precalciner dry process cement plant with a cement output of 1 Mt/y located in NE Scotland, UK. Process Flow Diagrams (PFDs) and heat and mass balance calculations for both options were developed. The plant costs were estimated and the costs per tonne of CO2 emissions avoided and per tonne of cement product determined. [Copyright &y& Elsevier]

Abstract: Greenhouse gas emissions from industrial processes, such as cement manufacturing or steel production, in Australia accounts for more than 40 Mt CO2-e per annum, representing close to 20% of Australia’s potentially sequesterable emissions. Further, the emissions from these processes are highly concentrated in CO2 compared to the emissions from power generation. It is not clear if these higher concentrated gases may provide low cost options for demonstrating CO2 capture or if this benefit will be lost due to the smaller total volume of CO2 emissions of most industrial processes. Nevertheless, this sector of the economy requires further analysis. This paper will provide an overview of the emissions from Australian cement sector including both the emissions from the chemical process itself, as well as the associated emissions from energy use within those processes. Specific attention will be focused on the Australian cement industry. While CCS involves the integrated part of capture, transport and storage, the focus of this paper is on the capture side and will illustrate CCS options for the cement industry. [Copyright &y& Elsevier]

Abstract: In solvent absorption systems for carbon dioxide capture, potassium carbonate shows particular promise as a solvent. One of the advantages of this solvent is that it is more manageable by way of separation and/or cost effectiveness in the presence of SO2. This paper examines the feasibility of using the same absorber system for simultaneous capture of both CO2 and SO2 from post combustion flue gases. Using a dynamic equilibrium apparatus, the changes in the vapour pressure were measured upon the introduction of sulphur dioxide to a CO2/ N2 mixed gas stream. It has been shown that there is a small change in the resultant vapour pressure. The overall affect of SO2 on the efficiency of CO2 capture is discussed. [Copyright &y& Elsevier]

Abstract: The effect of the increasing concentration of CO2 in the atmosphere on climate change is a major driving force for the development of advanced energy cycles incorporating CO2 management options. Growing interest in the technical and economic feasibility of CO2 capture from large coal-based power plants has led to increased efforts worldwide to develop new concepts for greater CO2 reductions in the future. Greenhouse gas emissions, especially CO2, have to be reduced by 50–80% by 2050, according to the IPCC . The type of fuel used in cement manufacture directly impacts on CO2 emissions, with coal accounting for around 60–70% of CO2 emissions from cement installations. Therefore, the large amount of carbon dioxide emitted during cement manufacturing process - 5% of the total emissions of CO2 from stationary sources worldwide - is a cause of great concern and has to be tack led in order to comply with current legislation. Several technologies are available and have been proposed for the separation of CO2 from the flue gases from new and existing plants with retrofit capture units. Few studies have been undertaken on CO2 capture in cement plants to assess the suitable technologies, with oxy-combustion and amine scrubbing as the possible options (pre-combustion capture not being viable). This paper summarises the different CO2 capture technologies suitable for cement industry and assesses the potential of the calcium looping cycle as a new route for CO2 capture in the cement industry. The potential advantage of this system is the very low efficiency penalty expected (<6%) compared with other capture technologies as the heat required for calcination is balanced by heat released during the carbonation (CO2 capture) step and can be utilized efficiently at high temperature in the plant’s steam cycle. Since limestone is already used for cement manufacture, and because it is a cheap material with good geographical distribution, it allows the use of local limestone resources with minimal limestone-related infrastructure investment. Another envisaged benefit of this new technology is that the lime purged from the cycle could be us ed as a raw material for the production of cement clinker. Therefore, the calcium looping cycle can potentially have an important impact in reducing CO2 emissions from the cement industry, and may also be applicable in other sectors. [Copyright &y& Elsevier]

Abstract: This paper recognizes the urgency of implementing large-scale carbon capture and storage facilities, and discusses the technological challenges associated with scale-up. Historical data of scaling factors commonly used for chemical processes are investigated and compared to CO2 capture technologies. Furthermore, the traditional chemical engineering approach to the scale-up path from laboratory, via pilots, to commercial design is compared to the principles of a newly developed guideline by Det Norske Veritas (DNV) for “Qualification of CO2 capture technology”. The guideline is based on DNV’s generic recommended practice for qualification of new technology, DNV-RP-A203. The procedure explains how to identify, describe, and manage risks (failure modes or threats) with the implementation of new CO2 capture technology in a semi-quantitative way by following a set of sequential steps known as the qualification process.x [Copyright &y& Elsevier]

Abstract: This paper evaluates the opportunities and associated costs for post-combustion capture at a world-scale complex refinery. It is concluded that it is technically feasible to apply post-combustion capture at such a refinery. The CO2 source most suited for capture appears to be a combined stack, but there are a number of other sources that may be targeted at comparable costs. In total these sources may form about 40% of the overall refinery emissions. Our evaluations show the costs of capture from such sources based on available amine technology will be about 3–4 times higher than the current carbon trading values. The capture of CO2 from a large amount of smaller CO2 sources will bring along even much higher costs. A high-level study of the CO2 emissions profile of a number of Shell refineries shows that, typically, up to 50% of the emitted CO2 may be captured at costs comparable to those found at the reference refinery. About 10–20% of concentrated CO2 associated with hydrogen manufacturing may be captured at lower costs. The remainder of emitted dilute CO2 will bring along significantly higher costs. Based on this study, it is concluded for the justification of the implementation of post-combustion capture at refineries, either a significant increase in carbon trading values, mandatory regulations, or a major technological break-through is required. [Copyright &y& Elsevier]

Abstract: Carbon dioxide is considered to be one of the main contributors of the world climate change and flue gases from power plants emit the most CO2. To reduce the carbon footprint, CO2 capturing from flue gas becomes increasingly unavoidable to meet the CO2 emission requirements. CO2 removal with amine solvent has been gaining more and more attention as it may be the only feasible approach technically and economically. Formulated amine solvents are promising over traditional amine solvents to enhance the CO2 absorption considerably, Kohl and Nielsen (1997) . It can be seen as a challenge for a CO2 removal unit to handle flue gas with a variety of CO2 concentrations, especially when the power plant is upgraded, in which its flue gas becomes enriched with CO2. In this paper, a comparison study is carried out to demonstrate the economic potential of capturing CO2 from enriched and non-rich CO2 flue gas stream with Monoethanolamine (MEA) and HTC formulated amine solvent, which is based on mixed amines. Flue gas from combined heat and power plant with 3.5 mol.% CO2 is used as a base case and enriching it with CO2 up to 9.2 mol.% is done to simulate the gas turbine exhaust gas recycling. The study shows that it is advantageous to use HTC formulated solvent over the conventional MEA solvent mainly due to its lower steam consumption, circulation rate, power requirements, and cooling water requirements. The study also shows that the working capacity of the HTC formulated solvent is higher than the MEA solvent. These findings result in significant operating cost savings when processing enriched CO2 flue gas stream using HTC formulated solvent. [Copyright &y& Elsevier]

Abstract: If CO2 emissions are to be reduced to control global warming, many large scale projects will need to be executed on a short term that capture and sequester the CO2. Most studies to date have focused on CO2 capture from power plant flue gas and concluded that the cost of CO2 scrubbing is in itself expensive and that more mature and efficient technologies are needed. CO2 emission control is also complicated by the need to provide SO2 and NOx emission control as well. Burner modifications can be used to control NOx, but other scrubbing technologies are needed to control SO2 emissions. For high sulfur coals, limestone scrubbing is generally applied, adding to the cost of power through purchases of limestone reagent and disposal of by-product gypsum. Cansolv has evolved amine based regenerable technologies that capture SO2 and CO2 and that release them in a water wet, nearly pure condition. SO2 can be converted to sulfuric acid and CO2 can be dried, compressed and sequestered without further treatment. Most importantly, energy used to capture SO2 can be recycled to help capture CO2, reducing the net energy demand of the CO2 process. The use of these two technologies together allows power companies to use higher sulfur, lower cost fuels and reduce energy consumption rates for CO2 capture. By-product sulfuric acid from the SO2 scrubbing system also provides a ready source of revenue to offset scrubbing costs. Cansolv has proven its SO2 scrubbing technologies in commercial applications since 2002. It has operated CO2 pilot plants at several different locations, logging over 6,000 hours of operation. The two technologies will come together in an integrated system, in a plant designed to generate 50 tons per day of CO2, which will start up in 2009. This paper presents important design and performance advantages of these systems. [Copyright &y& Elsevier]

Abstract: At present, the use of fossil fuels in the current energy mix represents the largest source of carbon dioxide (CO2) emissions, an important greenhouse gas (GHG), which is largely blamed for global warming. It is estimated that roughly 26 to 30 percent of all CO2 emissions due to human activities come from fossil fuels used for generating electricity. Moreover, a variety of other industrial processes such as oil refineries, fertilizer and cement plants also emit large amounts of CO2. The opportunity therefore exists for a significant reduction of CO2 from industrial processes and power plants through CO2 Capture and Storage (CCS). Currently, there are three main pathways to capturing CO2 from fossil fuel energy conversion processes, namely, pre-combustion capture, post-combustion capture, and oxy-fuel combustion with CO2 capture. Among these approaches, pre-combustion and oxy-fuel combustion take advantage of the fact that CO2 capture is further facilitated by increasing the concentration of CO2 in the flue gas stream, or by increasing the flue gas pressure, or both. There are several different processes available for CO2 capture and compression from low-pressure flue gas streams rich in CO2. These processes vary from simple straight or once through low-temperature separation and compression to more complex processes involving some form of recycle and/or auto-refrigeration. Given the economic constraints often placed on the cost of CO2 capture, and based on energy demand of each process, the ultimate success of these processes hinges on further refining the existing ones or developing new processes that can lower the cost of CO2 capture. The CANMET Energy Technology Centre in Ottawa is currently pursuing a leading research and development program in the field of near-zero emission fossil fuel technologies. This program includes the development of next generation oxy-fuel combustion technologies, as well as the design and development of efficient CO2 capture and compression processes to recover CO2 from oxy-fuel and other fossil fuel energy conversion systems. In this paper, we present and discuss the technical challenges, development stages and commissioning of the CANMET’s pilot-scale CO2 capture and compression unit (CO2CCU). This pilot-scale CO2 separation and compression unit provides an excellent test platform to study the impact of flue gas impurities on the CO2 capture process. This advanced gas separation system is first-of-a-kind pilot-scale unit that represents an integrated approach to oxy-fuel combustion of coal and other fossil fuels with CO2 capture for storage. [Copyright &y& Elsevier]

Abstract: This paper describes a detailed process optimization of the mass and energy balances for multi-stage membrane systems used in coal-fired power plants. Based on the recovery rate of 50% or 90% CO2 with 95 mol% CO2 purity, different concepts using recirculation of flue gas and variation of feed gas compressor and vacuum pump on the permeate side were developed and optimized to obtain minimum energy consumption. Simultaneously, a cost model was developed to make a further analysis of the optimized concept in view of the tradeoff balance between material and energy consumption. [Copyright &y& Elsevier]