Masaki Iijima

Development of energy saving technology for flue gas carbon dioxide recovery in power plant by chemical absorption method and steam system

The most important issue involved with the chemical absorption method for recovering carbon dioxide from a power plants flue gas is to develop energy-efficient absorbents. KS-1 absorbent was presented at ICCDR-2 in Kyoto. After the conference, efforts to develop energy-efficient absorbents have been made and a new absorbent KS-2 was developed as a result and its performance confirmed by the pilot plant. KS-2 has similar energy efficiency as KS-1 both of which require 20% less energy than MEA. KS-2 is however more stable than KS-1 and a more efficient absorbent for low CO2 content flue gas. Detailed steam system was also discussed in this conference and accurate calculation results were presented.

Subterranean Containment and Long-Term Storage of Carbon Dioxide in Unused Aquifers and in Depleted Natural Gas Reservoirs

Abstract There exist huge volumes of unused aquifers in the earth due to high salinity of the groundwater. Deep aquifers can contain large amount of CO 2 in the form of compressed gas, liquid or aqueous solution under high formation pressure. Natural gas dissolved in saline groundwater is exploited in some areas in Japan. A preliminary technical and economic survey on the CO 2 injection system suggests favorable results. More investigations are necessary for assessment of the effect of CO 2 injection on groundwater environment.

Development of flue gas carbon dioxide recovery technology

Abstract In Japan, electric power companies account for about 30% of the total emitted CO2. Considering this, the Kansai Electric Company and Mitsubishi Heavy Industries are actively conducting research into flue gas carbon dioxide recovery. The research involves laboratory tests, bench scale tests, pilot plant tests and feasibility studies. The main efforts have been directed towards evaluating CO2 absorption performance, treating impurities in the flue gas and finding the most efficient integration of the CO2 recovery system into thermal power plants. This paper presents the results of these studies and outlines the areas where cost and energy savings can be made, to allow the practical use of flue gas carbon dioxide recovery processes in the power plant.

Deep sub-seabed disposal of CO2 — The most protective storage —

The sub-seabed disposal of CO2 is safer than the disposal of CO2 in inland aquifers. Even if small amounts of CO2 seeped out of sea floor, CO2 would disperse and dissolve into sea water. On the surface of the sea, there exist no depressions where CO2 may concentrate. Sediments under deep sea floor are very cool because the deep oceanic water is usually at a few degrees centigrade. CO2 hydrate is formed in sediments under wide areas of ocean floor deeper than about 300m. Virtually complete isolation of huge amounts of CO2 is possible by the deep sub-seabed disposal. Liquid CO2 with heavy suspension intrudes laterally under light unconsolidated sediments at sea floor deeper than about 3700m. Lateral intrusion technique for the super-deep sub-seabed disposal of CO2 can protect the ecology on the sea floor.

Hydrate formation in sediments in the sub-seabed disposal of CO2

Sub-seabed disposal is the safest disposal option for CO2. Water pressure and dilution into oceanic water prevent direct emission of CO2 into the air. Sediments under the deep sea floor are usually cool because the deep oceanic water is very cool. CO2 hydrate forms in the sediments in areas of the sea floor deeper than 300 m. The formation of CO2 hydrate in sediment pores almost completely prevents the escape of CO2.

Carbon dioxide injection into useless aquifers and recovery of natural gas dissolved in fossil water

Abstract Huge reserves of natural gas in saline aquifers remain still unused in many sedimentary basins in the world. The authors propose an underground injection system of gaseous carbon dioxide into useless saline aquifers in sedimentary basins. The gaseous carbon dioxide is recovered from flue gas of fossil fuel fired power stations possibly by amines. Recovery of natural gas dissolved in the pumped-up saline groundwater can compensate the loss of electric power for the carbon dioxide injection. Our tentative survey suggests that small fractions of useless saline aquifers in sedimentary basins in the world are enough to host about 320 gigaton of carbon dioxide. A preliminary technical and economical survey was conducted on this carbon dioxide injection system for fossil fuel fired power plant. The CO 2 emission-free electric power generation is possible by this underground carbon dioxide injection system with the probable 35% cost increase for LNG fired power plant or 60% increase for coal fired power plant.

Flue Gas CO2 Recovery and Compression Cost Study for CO2 Enhanced Oil Recovery

Publisher Summary Oil companies are currently investigating the possibility of recovering CO 2 from flue gases for use in EOR. Meanwhile, some research institutes are investigating the possibility of recovering CO 2 from flue gases and disposing of them into aquifers to reduce the emission of CO 2 into the atmosphere. This chapter evaluates the technical feasibility of CO 2 recovery from flue gases, and estimates the cost per MSCF of CO 2 recovery/compression for various CO 2 sources. This chapter focuses on some of the economic study results to identify which parameters affect CO 2 delivery costs based on the commercial experience of flue gas CO 2 recovery system. A comprehensive economic study has been carried out on CO 2 recovery plants in the Middle East area for the purpose of Enhanced Oil Recovery (EOR) based on various parameters, included the capacity of the CO 2 recovery unit, the utility cost, the pipeline cost, and any other operational requirements. A cost analysis of CAPEX, OPEX, and the sensibility of various parameters affecting the CO 2 recovery cost are presented.

Improvements of carbon dioxide capture technology from flue gas

Publisher Summary This chapter discusses that Mitsubishi heavy industries, ltd. (MHI), and Kansai electric power co. (KEPCO) jointly developed the post combustion amine scrubbing technology. KEPCO & MHIs flue gas CO2 recovery process that use proprietary hindered amine with special equipment. The main objective of this chapter is to achieve economical CO2 recovery for enhanced oil recovery (EOR) or storage. It includes the design of large CO2 recovery plant and process optimization for operational cost reduction. Performance of the advanced KEPCO & MHIs flue gas CO2 recovery process is compared to its predecessor process. It concludes that improved heat recovery around CO2 stripper resulted in 15 % reduction of steam requirement for regeneration. Solvent loss is reduced by installing proprietary device at the top of absorber, and structured packing enabled compact tower, to increase flue gas velocity and power reduction of flue gas blower.

Life Cycle Assessment for CO2 Capture Technology from Exhaust gas of Coal Power Plant

Publisher Summary This chapter analyzes the fuel energy cycle system covering the CO 2 capture technology from exhaust gas of coal power plant using Life Cycle Assessment (LCA) according to the scenario based on the calculation of the criteria from fuel production, transportation, power generation, to CO 2 recovery and storage, focused on coal. The energy and environmental performances were analyzed for mass (carbon) and heat (energy) balance and three cases were compared for the entire fuel cycle. These cases are based on the pulverized coal fired plant (PCF). The conclusion of LCA is that direct CO 2 emission from power generation, or the CO 2 recovery in the operation phase, influences greatly their environmental load. In the energy balance, net power generating efficiency for the “base case” is 40.6%. Results from the study showed a reduction to 33-30% caused by the CO 2 recovery, and the total life cycle electricity generation efficiency including off-site energy consumption was 32-29%; it was recognized that off-site energy consumption was very limited. In the carbon balance, when the CO 2 capture ratio of 90% was applied, the CO 2 emission reductions were 86-85% on the entire fuel cycle, including off-site emission. It was shown that the “MHI CO 2 recovery technology” was a higher energy efficiency system than “conventional technology.”

Recent Developments on Flue Gas CO2 Recovery Technology

Publisher Summary The Kansai Electric Power Co. (KEPCO) and Mitsubishi Heavy Industries, Ltd. (MHI) have been carrying out joint work on research and development of new technology for CO2 recovery from power plant boiler flue gas and gas turbine exhaust gas. From the results of this research and development work, an energy efficient solvent was developed and commercialized. The first commercial plant using this solvent has been operated since October 1999 in Malaysia. This chapter describes the recent research and development activities since the GHGT-5 disclosure. The Kansai Electric Power Co. Inc. and Mitsubishi Heavy Industries, Ltd. have been making continuous efforts to improve flue gas CO2 recovery technology. The recent improvements have been focused on the reduction of the initial costs and operation costs. The recent main research and development items are increase of flue gas velocity in the CO2 Absorber, reduction of the KP-1 packing weight, and reduction of amine consumption. These items have been put to the test in the Nanko Power Station pilot plant and their performances have been confirmed. In addition to the above, development on new energy efficient solvents has been carried out. A new bench scale testing facility enabled very accurate measurement of the CO2 recovery energy consumption to be made; this was the same as that of the pilot plant and was used for the evaluation of new solvents.