Sohei Shimada

Mechanism of methane flow through sheared coals and its role on methane recovery

Abstract Tectonically sheared coals are closely related with coalbed methane exploitation, and are classified into cataclastic coals and mylonitic coals in view of their deformation mechanism, either brittle or ductile. Scanning electron microscopy and reflected light microscopy observations showed that cataclastic coals possess a hierarchy of open, continuous and connecting fractures, whereas mylonitic coals always display tightly compressed and collapsed fractures. Mercury porosimetry studies also indicated that compared with normal coals, cataclastic coals possess greater porosity, more specific surface area and wider average fracture aperture; whereas mylonitic coals are characterized by narrower average fracture aperture and a great deal of specific surface area. Based on experimental data and actual site experiences, a new model of methane flow within coals was proposed. Gas flow through sheared coals, unlike normal coals—a simple dual porosity system comprising a matrix of micropores that are surrounded by cleats, also contain additional steps because of overwhelming sheared fractures and different deformation mechanisms. This model can explain why gas outbursts are always accompanied by small-scale compressively geological structures where mylonitic coals often occur, and why in such area the rate of gas extraction is unexpectedly lower, despite the presence of a great volume of methane.

Influence of biological pre-treatment of municipal solid waste on landfill behaviour in Sri Lanka.

Sri Lanka is an island in the Indian Ocean with an area about 65 610 km2. The population of the country is around 20.2 million. Hazardous disposal of municipal solid waste (MSW) is a major concern particularly in the most urbanized areas of Sri Lanka. However, the current waste management system does not facilitate any waste pre-treatment techniques before final disposal. As a consequence, there is immense pressure to improve the waste disposal practices in the country. Under the above circumstance, this study is an attempt to examine the influence of biological pre-treatment of MSW on landfill behaviour in Sri Lanka. Field-scale lysimeters with untreated and biologically pre-treated MSW were used for this study. The data was obtained on leachate quantity, quality, and settlement. The ambient parameters were also measured at the experiment site. According to the results, the effect of rainfall incident on leachate generation was visible but the effect on pre-treated waste was comparatively less than untreated waste. The organic pollutant load in leachate of pre-treated MSW was seven times lower than that of untreated MSW. The settlement of the lysimeter with pre-treated MSW was comparatively less. It can be concluded that the process of biological pre-treatment of MSW by composting is an effective method for Sri Lanka and also it reduces the health and environmental risks by improving the behaviour of landfill.

Study on Drying Organic Sludges by Thermal Jet Dryer—Part 2: Characteristics of Air-Particle Multiphase Flow in Thermal Jet Dryer

The authors are developing a thermal jet dryer (TJD) with a vertical disc-shaped drying tank for the purpose of reducing the volume of solid wastes with high water content, such as organic sludges. In order to obtain the characteristics of air-particle multiphase flow in a TJD, cold model experiments and computational fluid dynamics (CFD) simulations were conducted. The following results were obtained: (1) A combined eddy was generated in the tank, such as in a cyclone separator. (2) “Cascading” phenomena occurred in the particle discharging mechanism. (3) In the TJD, particles maintained consistent drying conditions throughout the drying process.

Economic Assessment of CO 2 Sequestration in Coal Seams

This chapter presents the cost and environmental load analysis of CO 2 sequestration systems in coal seams. Two types of injection gas were considered: CO 2 and flue gas. For the CO 2 injection, the system is composed of combustion of natural gas and/or coal in a power station, CO 2 separation from flue gas, CO 2 injection into a coal seam, CH 4 production by the CO 2 replacement in the coal seam, and CH 4 supply for power generation. For the flue gas injection, produced CH 4 with N 2 is separated after production from a well. To estimate the amount of CO 2 sequestration and CH 4 production, Enhanced CBM Recovery Simulator (ECOMERS) is under developing. The environmental load of this system was evaluated by LCA. The economic and environmental load analyses were made for the ECBMR using CO 2 and flue gas injection. The cost for the CO 2 sequestration by this method was estimated to be around US

COST ESTIMATION OF UNDERGROUND COAL GASIFICATION IN JAPAN

60/t-CO 2 . In terms of the CO 2 emission, ECBMR with CO 2 injection is a promising method.

Evaluation of RDF Power Generation of Large-Area Waste Treatnment by LCA

Underground Coal Gasification (UCG) is one of the methods of recovering energy from underground coal seams. In 1970’s and 1980’s, many basic studies and field tests on UCG were carried out in the USA. Although the activity on UCG has been interrupted, because of the recent low oil price in the world energy market, the technologies and concepts developed in this period are remarkable. Since the 1960’s almost no studies on UCG have been made in Japan. The authors made a cost estimation on UCG in JAPAN, applying the new technologies developed in the USA and data obtained in the field tests there. This study includes the selection of the best site for UCG in Japan from the viewpoint of geological conditions, the prediction of product gas component and the cost estimation. Two UCG methods, ELW (Extended Linked Well) and CRIP (Controlled Retracting Injection Point), were taken into consideration for cost comparison. Our assumption was gasification of one million tons of coal within a period of 10 years. The production cost of gases per heating value was estimated to be between US

Flame Jet Engineering and Its Application for Processing and Recovery of Waste.

0.029/MJ and US

For Establishment of Coalbed Technology.

0.045/MJ. Finally, the authors proposed a boring cost saving UCG method, STRIP (STream Method with Retracting Injection Point) method, for its further technical development.

MEASUREMENT OF PROPERTY CHANGE OF COALS STORED IN STOCKPILE FOR A LONG TIME

Publisher Summary This chapter evaluates the viability of refuse-derived fuel (RDF) power generation from the viewpoint of energy saving and the reduction of CO 2 emissions by analyzing operations at the Kashima RDF power plant, which has been running since fiscal year 2001. It considers the thermal recycling system most suitable for a given area. RDF has the advantages of being easy to transport and store and has a high calorific value. On the other hand, it has the disadvantage of requiring extra energy for manufacturing RDF itself. Kashima City, Kamisu Town and Hasaki Town run the Kashima RDF power generation operation. Although power generation and heat supply were originally planned, the latter was abandoned because of the lack of demand in this area. LCA (Inventory Analysis) is adopted as an evaluation method. In the application range of Life Cycle Assessment (LCA), not only the operating process but also the construction and dismantling processes are included. Five cases are evaluated from the viewpoint of saving energy and the reduction of CO 2 emission to find the most suitable RDF power generation system. From the result of detailed analysis of each life cycle process in the present operation, it was found that the introduction of RDF power generation did not produce much advantage under present conditions. However, it was found that it would save energy and reduce CO 2 emissions if it were used to produce significant electrical output by large-area waste treatment.

Current state and environmental impact assessment for utilizing oil palm empty fruit bunches for fuel, fiber and fertilizer - a case study of Malaysia.

フレームジェットとは, ジェットバーナと呼ばれる燃焼器から発生する火炎 (フレーム) をいう。この火炎は, 火炎ジェットともいわれ, 高温・高速であるので, この火炎を利用して, 作孔, 切削, 乾燥, 蒸発, 破砕, 粉砕, 熱分解などのさまざまな作業や操作ができる。フレームジェットは元来, 岩石の作孔を目的として開発された技術であるが, 現在は, この熱作孔機としての利用の他に, 化学プラントの熱発生装置としてあるいは廃棄物の乾燥・解砕処理としての利用法が注目されてきている。本報では, フレームジェットの発生機構, ジェットバーナ運転システム, フレームジェットを用いた廃棄物処理・資源化システムの特長, 廃棄物処理例, 本システムの問題点と課題を解説した。