ORCID Profile
0000-0001-9079-469X
Current Organisations
RTI International
,
Ministry of Power, Energy and Mineral Resources
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Publisher: Elsevier BV
Date: 09-2010
Publisher: Akademia Baru Publishing
Date: 24-08-2021
DOI: 10.37934/ARFMTS.86.2.2838
Abstract: Underground Coal Gasification (UCG) is thought to be the most favourable clean coal technology option from geological-engineering-environmental viewpoint (less polluting and high efficiency) for extracting energy from coal without digging it out or burning it on the surface. UCG process requires only injecting oxidizing agent (O2 or air with steam) as raw material, into the buried coal seam, at an effective ratio which regulates the performance of gasification. This study aims to evaluate the influence of equivalent ratio (ER) on the flow and combustion characteristics in a typical half tear-drop shape of UCG cavity which is generally formed during the UCG process. A flow modeling software, Ansys FLUENT is used to construct a 3-D model and to solve problems in the cavity. The boundary conditions are- (i) a mass-flow-inlet passing oxidizer (in this case, air) into the cavity, (ii) a fuel-inlet where the coal volatiles are originated and (iii) a pressure-outlet for flowing the product Syngas out of the cavity. A steady-state simulation has been run using k-? turbulence model. The mass flow rate of air varied according to an equivalent ratio (ER) of 0.16, 0.33, 0.49 and 0.82, while the fuel flow rate was fixed. The optimal condition of ER has been identified through observing flow and combustion characteristics, which looked apparently stable at ER 0.33. In general, the flow circulation mainly takes place around the ash-rubble pile. A high temperature zone is found at the air-releasing point of the injection pipe into the ash-rubble pile. This study could practically be useful to identify one of the vital controlling factors of gasification performance (i.e., ER impact on product gas flow characteristics) which might become a cost-effective solution in advance of commencement of any physical operation.
Publisher: Bangladesh Journals Online (JOL)
Date: 24-05-2022
DOI: 10.3329/DUJEES.V10I3.59076
Abstract: The Jamalganj coalfield with the coal deposits of the Permian Gondwana Group in the halfgraben basin was discovered in Joypurhat District, Northwestern Bangladesh, sometime in 1962. In idual coalbed thickness ranges from 0.60 m to 42 m and seams were encountered between the depth ranges of 640 m and 1158 m. Since mining has not yet begun due to the greater depth of the coal seams, several researchers have proposed a Coalbed Methane (CBM) exploration in this region. This research focuses on the permeability of the Jamalganj coal derived from the in-situ Injection Falloff Test (IFT), which is an important reservoir parameter and one of the key factors in CBM exploration and Underground Coal Gasification (UCG). In addition to that, the relationship of temperature and skin factor with permeability is one of the key findings of this research, permeability obtained from the IFT ranges from 2.57 to 121.16 mD while the skin factor ranges from - 6.11 to 50.85 and a higher temperature gradient as of about 4°C per 100 m depths was observed. The study shows that temperature has an inverse relationship with the permeability that decreases with depth and temperature increases, which is analogous with the other CBM producing reservoirs around the world. The negative skin factor denotes flow enhancement near the wellbore and a well-stimulated reservoir, and the positive skin factor indicates increased flow resistance near the wellbore, which reduces permeability. The permeability data suggest that the analyzed coal seams of the Jamalganj Coalfield are suitable for unconventional gas production by either CBM or UCG development. The Dhaka University Journal of Earth and Environmental Sciences, Centennial Special Volume June 2022: 103-112
Publisher: Association for Computing Machinery (ACM)
Date: 03-2002
Abstract: Real-time collaborative graphics editing systems allow a group of users to view and edit the same graphics document at the same time from geographically dispersed sites connected by communication networks. Consistency maintenance in the face of concurrent accesses to shared objects is one of the core issues in the design of these types of systems. In this article, we propose an object-level multiversioning approach to consistency maintenance in real-time collaborative graphic editors. This approach is novel in achieving intention preservation and convergence, in preserving the work concurrently produced by multiple users in the face of conflict, and in minimizing the number of object versions for conflict resolution. Major technical contributions of this work include a formal specification of a unique combined effect for an arbitrary group of conflict and compatible operations, a distributed algorithm for incremental creation of multiple object versions, a consistent object identification scheme for multiple object versions, and a convergent layering scheme for overlapping objects. All algorithms and schemes presented in this article have been implemented in an Internet-based GRACE (graphics collaborative editing) system.
Publisher: Elsevier BV
Date: 07-2023
Publisher: Elsevier BV
Date: 11-2021
Location: Bangladesh
Location: United States of America
Location: United States of America
No related grants have been discovered for Arup Kumar Biswas, Ph.D..