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IHI has been developing oxyfuel technology as one of the CO2 capture technologies from coal fired power plants since 1989. For the demonstration of oxyfuel combustion technology, IHI jointly formed and participated in “Callide Oxyfuel Project” with Australian and Japanese partners in 2008. In the Project, the applicability of the technology to an existing power plant, the reliability and the effectiveness for CCS were demonstrated through achievement of more than 10,000 hours oxyfuel operation and underground injection of CO2 that captured from oxyfuel coal power plant. After completion of the demonstration, additional tests were carried out in the laboratory and at the pilot-scale combustion test facilities in IHI’s Aioi Works. The additional test purpose is to check the performance of the equipment mostly used in current power plants in order for the technology to be flexibly applied to them. For example, the vertical type roller mill and the ESP were tested. In vertical type roller mill test, it was made clear that the effect of moisture concentrated in the flue gas in oxyfuel system was not so big for the pulverization of coal. In ESP test, it was clearly found that the dust collection efficiency in oxyfiring combustion is higher than that in airfiring combustion.

In 2013, CO2 levels surpassed 400 ppm for the first time in recorded history. So, we are facing global warming due to the increase levels of atmospheric carbon dioxide (CO2). As a method of reducing CO2 emissions from the thermal power plants, there are carbon dioxide capture and storage (CCS) technologies. Oxyfuel combustion is one of the CO2 Capture technologies and IHI have developed it since 1989. Then, Callide Oxyfuel Project commenced to apply oxyfiring technology in an existing coal fired power plant and to demonstrate an oxyfuel power plant in March, 2008. Demonstration began in 2012 after existing boiler was retrofitted. During the demonstration for approximately three years, many tests were conducted and many data were collected for commercial use. As a result, we confirmed characteristics of oxyfiring such as total heat absorption, combustion characteristics, emissions of NOx, SOx, carbon-in-ash, operational flexibility from 15MWe (50%L) to 30MWe (100%L) and behavior of injected CO2 at the injection site. Total heat absorption of the boiler under oxyfiring was 2 to 3MW higher because of decreasing heat loss in flue gas and rising temperature of boiler feed water by a flue gas cooler. NO was decomposed in the furnace under oxyfiring because flue gas was recirculated. On the other hand, reaction between SO2 and absorbent such as Ca, Mg in ash was not so active regardless of high concentrated SO2 under oxyfiring. Carbon-in-ash was almost 40%~70% in oxyfirng compared with in airfiring because of longer residence time in the furnace. Operational flexibility is important to control oxyfiring operation and it was confirmed that oxyfiring can be operated as well as airfiring. In this paper, operational results are presented in Callide Oxyfuel Project.

Callide Oxyfuel Project is the only demonstration project for oxyfuel power plant in the world and has been promoted at Callide-A power station in Queensland, Australia. Callide-A power plant, which is a retrofit of an existing power plant with a capacity of 30MWe, is now the largest operating oxyfuel power plant all over the world. Two air separation units (ASU) of 330 TPD and CO2 compression and purification unit (CPU) of 75 TPD that is about 10% capacity of total flue gas were newly installed. And the existing 30MWe boiler was modified to apply both air and oxufuel combustion. This demonstration is the key and important step for the large-scale oxyfuel power plant in the future and the various tests regarding the oxyfuel boiler and CPU have been performed. Main objectives of this project are to demonstrate the oxyfuel operation with CO2 capture and storage using the existing power plant and to obtain the design data and operation know-how for the commercialization.Callide-A oxyfuel boiler with power generation and CO2 purification unit from oxyfuel flue gas have been demonstrated and have given us the various operation results with some test parameters in the Project. Regarding the oxyfuel boiler, the heat absorbed rate, combustion characteristics, trace elements behaviour and plant operation flexibility have been confirmed at the different coal type and the different boiler inlet O2 concentration with the various power generation output through the commissioning and demonstration stage.In this paper, the operational experiences of the oxyfuel power plant in Callide Oxyfuel Project are introduced.

CCS, CO 2 capture and storage, is one of the ways to keep CO 2 concentration in atmosphere to be under certain value in order to mitigate the global warming and expectation for its practical use soars all over the world. IHI have developed the oxyfuel combustion technology as CO 2 capture technology since 1989 and we have been going forward the Callide oxyfuel Project in Australia since 2008. In this paper, we introduce the progress of the Callide oxyfuel Project and the action toward the practical use of the oxyfuel combustion technology.

In-situ CO 2 capture in coal utilization captures CO 2 during coal combustion or gasification such as Oxygen fuel combustion or HyPr-RING. coal gasification processes. Regarding Oxufuel combustion, Callide Oxyfuel Project has been being conducted as the world first project to apply the technology to an existing power plant, Callide A Power Station #4 unit (30MWe) with injection of captured CO 2 into the underground. This is a Japan-Australia collaboration project and JCOAL participates in it as a supporting collaborator. JCOAL also proposed a novel coal gasification method-,HyPr-RING (Hydrogen Production by Reaction-Integrated Novel Gasification). HyPr-RING method utilizes a chemical looping with the calcium cycle, in which CaO (or Ca(OH) 2 ) captures CO 2 during coal gasification completely to form CaCO 3 and release heat for gasification to produce near pure hydrogen in one gasifier. This paper introduces the current developing status of the HyPr-RING method, mainly including the experimental examination of the transition of sorbent particle size distribution, ash and sulfur concentration of materials at several locations of gasification and calcination system for the HyPr-RING process. And the plant cold gas efficiency which should be affected by ash separation was also analyzed. As the results, it was found that coal ash and sulfur concentrated highly in the process of calcination after cyclone. If it is possible, separate and remove ash and sulfur by applying devices like filter or/and cyclone separator, the plant coal gas efficiency may raise 2 points than that in the previous study in which a part of recycled sorbent was rejected without separation. One method for reducing CO 2 , the green house gas emissions is to capture CO 2 before it releases into the atmosphere and then sequestrate it. Active lime (main component, CaO) can be used to capture CO 2 in the exhaust gas or in the reactor from fossil fuels utilization effectively. That is calcium oxide (CaO) absorbs CO 2 to yield calcium carbonate (CaCO 3 ) (Eq.(1)), then the CaCO3 is thermally decomposed to CaO again and release nearly pure CO 2 (Eq. (2)) for sequestration. To obtain a nearly pure CO 2 stream from CaCO 3 decomposition, the heat for decomposing CaCO 3 can be supplied by combusting fossil fuels, such as coal and natural gas, in a calciner with oxygen fuel combustion. The oxygen diluted by CO 2 (CO 2 cycle) or H 2 O (steam cycle), in order to obtain near pure CO 2 stream from CaCO 3 decomposition. In our previous studies 4−6 , it was clarified that calcinations of limestone (main component, CaCO 3 ) in a fluidized bed calciner can be performed in CO 2 cycle atmosphere when the bed temperature was raised above 1293 K, whereas with 60% steam cycle in atmosphere, limestone can be decomposed at comparatively lower temperature, such as 1173 K. The decomposition conversions of the limestone were about 95% and 98%, in CO 2 cycle and in steam cycle atmospheres, respectively. Reducing the calcinations temperature of limestone was helpful to produce more than 30% active CaO as shown in previous study 4−6 . In this study, the energy of CaCO 3 calcination process by H 2 O (steam) cycle was analyzed and compared with CaCO 3 calcination process by CO 2 cycle. For process calculations, the mass and energy flows were calculated iteratively, based on the input and output balances, until err [(input-output)/input] was 2 O (steam) cycle calcination had calcination energy more about 3.6% than CO 2 cycle due to water evaporation latent heat loss, however, the calcination energy per active CaO was lowest for H 2 O (steam) cycle.

One method for reducing CO2, the green house gas emissions is to capture CO2 before it releases into the atmosphere and then sequestrate it. Active lime (main component, CaO) can be used to capture CO2 in the exhaust gas or in the reactor from fossil fuels utilization effectively. That is calcium oxide (CaO) absorbs CO2 to yield calcium carbonate (CaCO3) (Eq.(1)), then the CaCO3 is thermally decomposed to CaO again and release nearly pure CO2 (Eq. (2)) for sequestration. To obtain a nearly pure CO2 stream from CaCO3 decomposition, the heat for decomposing CaCO3 can be supplied by combusting fossil fuels, such as coal and natural gas, in a calciner with oxygen fuel combustion. The oxygen diluted by CO2 (CO2 cycle) or H2O (steam cycle), in order to obtain near pure CO2 stream from CaCO3 decomposition. In our previous studie s4-6, it was clarified that calcinations of limestone (main component, CaCO3) in a fluidized bed calciner can be performed in CO2 cycle atmosphere when the bed temperature was raised above 1293 K, whereas with 60% steam cycle in atmosphere, limestone can be decomposed at comparatively lower temperature, such as 1173 K. The decomposition conversions of the limestone were about 95% and 98%, in CO2 cycle and in steam cycle atmospheres, respectively. Reducing the calcinations temperature of limestone was helpful to produce more than 30% active CaO as shown in previous stud y4-6. In this study, the energy of CaCO3 calcination process by H2O (steam) cycle was analyzed and compared with CaCO3 calcination process by CO2 cycle. For process calculations, the mass and energy flows were calculated iteratively, based on the input and output balances, until err [(input–output)/input] was

Abstract Coal-fired power plants produce flue gas consisting mainly of nitrogen (around 79%), followed by CO2 (around 10 - 15%), and small amounts of other gases such as H2, NOx and SO2. One of the promising methods for reducing CO2 emission is CO2 sequestration into deep, unminable coal seams. At present, flue gases exhausted from coal-fired plant must be separated to extract pure CO2 before injecting it into coal seams. In order to enhance the efficiency of carbon capture and storage (CCS) from a coal-fired power plant, oxy-fuel combustion technology has been employed. This technology uses pure oxygen to burn the coal, and consequently CO2 concentration in the flue gas is theoretically increased up to 95%. This study aims to simulate the CH4 replacement mechanism in coal by using pure CO2 and a synthesized flue gas (99% CO2 and 1% SO2) that is similar to the emission gas from the coal-fired power plants. A measurement procedure for gas adsorption is employed which, after establishing methane adsorption equilibrium of the coal samples, injects pure CO2 or the synthesized flue gas into an adsorption cell in order to investigate CH4 replacement properties. Coal samples used for the present experiments were taken from the coal seams of Vietnam, Japan, Australia, China and Indonesia. The samples were crushed to particle sizes ranging from 250 µm to 5 mm. The concentration of gases was taken from the adsorption cell and analyzed by using a gas chromatograph. Adsorption isotherms of CH4, CO2 and SO2 were measured by using the volumetric method apparatus. This paper discusses the characteristics of methane replacement by using pure CO2, the synthesized flue gas and the effect of SO2 on adsorption properties of coal. Introduction Global warming and climate change due to the greenhouse effect continue to be a serious problem. In particular, CO2 emission into the atmosphere from coal-fired power plants needs to be reduced. One of the most promising methods of reducing CO2 emissions is CO2 sequestration in deep, unminable coal seams. The CO2 adsorption capacities of coals were investigated by Huy et al.(1). The results showed that CO2 adsorption was double that of CH4.

Experimental measurements as well as theoretical models were used to investigate the impact of mineral matter of three coals on ash deposition and heat transfer for pulverized coal fired boilers. The ash deposition experiments were conducted in a pulverized fuel combustion pilot-scale facility and a full-scale unit. A mathematical model with input from computer-controlled scanning electron microscopy analysis of coal minerals was used to predict the effect of ash deposition on heat transfer. The predicted deposit thickness and heat flux from the model are shown to be consistent with the measurements in the test facility. The model differentiates the coals according to the deposits they form and their effect on heat transfer. The heat transfer predictions in the full-scale unit were found to be most suitable for the water wall under the furnace nose. The study demonstrates that the measurements in a full-scale unit can differ significantly from those in pilot-scale furnaces due to soot-blowing operations.

Coal is an abundant resource, found throughout the world, and inexpensive and constant in price. For this reason, coal is expected to play a role as one of the energy supply sources in the world. The most critical issues to promote utilization of coal are to decrease the environmental load. In this report, the history, outline and recent developments of the clean coal technology in Japan, mainly the thermal power generation technology are discussed. As recent topics, here outlined first is the technology against global warming such as the improvement of steam condition for steam turbines, improvement of power generation efficiency by introducing combined generation, carbon neutral combined combustion of biomass, and carbon dioxide capture and storage (CCS) technology. Also introduced are outlines of Japanese superiority in application technology against NOx and SO{sub 2} which create acid rain, development status of the technical improvement in the handling method for coal which is a rather difficult solid-state resource, and utilization of coal ash.

MEET (Multi-staged Enthalpy Extraction Technology) system is a new coal/wastes-fired power generation system. In order to establish the MEET system technology, a demonstration plant of commercial scale, MEET-II, was installed. The capacity of the MEET-II is 2 t/day of coal of 4 t/day of RDF. MEET-II consists of a pebble bed slagging-gasifier, a high temperature air generator, and a high temperature air combustion boiler. Gasification with high temperature air results in higher heating value of syngas. Cleaned-up syngas is used as a fuel for the boiler as well as for preheating air up to 1000 °C. Combustion and gasification tests at the MEET-II were conducted using pulverized coal as a fuel. Combustion experiments demonstrated almost complete char combustion with a short residence time, and gasification experiments demonstrated targeted calorific value of syngas, 1000 kcal/mN3.

The use of high-temperature, low oxygen-content air for pulverized coal combustion is presented. Laboratoryscale tests were conducted in a drop-tube furnace to cone rm the performance of such a combustion system. The furnace wall was maintained at 1300 ± C by a ceramic heater, and the high-temperature preheated air (around 1000 ± C) was supplied by a regenerative burner. NOx formation and combustion efe ciency of the furnace were measuredforvariousairpreheat temperature, excess-airratio, and oxygen concentrationintheair. Measurements indicatedthatincreasingairpreheatresultsinincreasedcombustionefe ciency andreduced NOxemission,whereas decreasing theoxygen contentofthecombustion airleads to largereduction in combustionefe ciency, accompanied witha slightdecreaseorincreasein NOx. Itcan beconcluded from thetestresults thattheuseof high-temperature, diluted air is not suited for pulverized coal combustion.

Pulverized coal combustion with oxygen and recycled flue gas constitutes a promising system to recover CO2 from the exhaust gases of boilers. Our previous combustion tests on this system suggest emissions of smaller amounts of NOx than in conventional combustion and reduced ignition stability of the burner. In order to improve the combustibility of the O2/CO2-pulverized-coal burner, numerical simulations and combustion tests were performed. An oxygen-injection nozzle was added to the burner. Simulation results predicted the effectiveness of direct oxygen injection and were confirmed qualitatively by bench-scale combustion tests on gas temperatures.

Oxyfuel combustion is able to directly make the highly concentrated CO2 from the flue gas of pulverized coal fired power plant and, therefore, is expected as one of the promising technologies for CO2 capture. We are advancing the Oxyfuel combustion demonstration project, which is called Callide Oxyfuel Project, with the support of both Australian and Japanese governments. Currently the boiler retrofit work is completed and the commissioning in air combustion is going on. In this paper, we introduce the general outline of the Callide Oxyfuel Project and its progress.

Oxy-fuel combustion is expected to be one of the promising systems on CO2 capture from pulverized-coal fired power plant, and enable the CO2 to be captured in a more cost-effective manner compared to other CO2 capture process with the power generation from the results of previous study. Some studies in this area are implemented under Australia-Japan consortium established in 2004 and joint venture for Callide Oxy-fuel Project under Australia-Japan consortium is established in March 2008. The project is now under way for the retrofit oxy-fuel combustion to an existing power plant by way of demonstration and is implemented in Callide-A power plant No.4 unit owned by CS Energy with a capacity of 30MWe in Australia. This project aims at capturing CO2 from an actual power plant for CO2 storage. The demonstration operation will start in 2011. One of the key issues to achieve the reliable and stable operation is countermeasure against corrosion. Recently, we studied the behaviors of corrosive substances in combustion gas and trace elements in flue gas, which is mainly sulfur compounds and Hg respectively. Sulfur compounds causes corrosion of boiler tubes, and Hg causes corrosion of aluminum base heat exchangers in the CO2 processing unit. Knowledge of their behaviors in oxyfuel is insufficient, and obtaining their knowledge is important for suitable material selection, countermeasure against corrosion, and optimal process design. In order to confirm the behaviors of corrosion components and Hg, the pilot-scale combustion test in IHI is performed at the combustion test facilities; the capacity of the furnace is 1.2MWt. The combustion test is conducted under oxy-fuel and air combustion conditions because of confirmation of the difference in both conditions. In this paper, the behaviors of corrosion components and Hg in the oxy-fuel combustion process are introduced. These results obtained in this study can significantly contribute to the design and the improvement of the oxyfuel combustion process towards the commercialization.

Oxy-fuel combustion is expected to be one of the promising systems on CO2 capture from pulverized-coal fired power plant, and enable the CO2 to be captured in a more cost-effective manner compared to other CO2 capture process. Some studies in this area were implemented under Australia-Japan consortium established in 2004. The comparative testing of the important components by using three Australian coals has been recently conducted under both oxy-fuel and air combustion conditions. The purposes of these tests were to obtain design data on flame stability, combustion characteristics and plant operation including turn-down test. The tests have indicated a number of important outcomes including a good comparison of normal air with oxy-fuel combustion, significant reduction in NO x mass emission rates under oxy-fuel combustion and the collection of data to validate other combustion modeling work.