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008 201110t20192019my a|||frm||| 00| 0 eng d
020 _aTHE0008341(Local)
_qhardback
040 _aUMP
_beng
_cUMP
_erda
090 _aFKKSA .A65 2019 r Thesis
100 0 _aNur Aqidah Muhammad Harinder Khan,
_eauthor.
245 4 0 _aThe evaluation of premixed biogas/air explosion characteristics in a 20 l closed vessel/
_cNur Aqidah Muhammad Harinder Khan
264 1 _aKuantan, Pahang :
_bUMP,
_c2019
264 4 _c© 2019
300 _axvi, 126 pages :
_billustrations (some color) ;
_c30 cm. +
_e1 CD-ROM
336 _atext
_2rdacontent
336 _atext
_2rdacontent
337 _aunmediated
_2rdamedia
337 _acomputer
_2rdamedia
338 _avolume
_2rdacarrier
338 _acomputer disc
_2rdacarrier
347 _atext file
_bPDF
_2rda
500 _aFaculty of Chemical and Natural Resources Engineering
502 _aThesis (Master of Engineering (Chemical)) -- Universiti Malaysia Pahang – 2019
504 _aIncludes bibliographical references
520 3 _aA gas explosion involving biogas is a severe phenomenon that results from the combustion of a premixed gas cloud. As of today, several explosion accidents involving biogas have been reported worldwide. Extensive and comprehensive studies have been done to investigate the factors contributing to the explosion (i.e. the fuel concentration, initial pressure and temperature, and carbon dioxide (CO2) dilution). However, these studies have only been done involving fuel/air mixtures other than biogas. Since biogas is composed of 50 to 70% methane (CH4), 30 to 50% CO2 and traces of other gases, it is highly combustible. Lacked in its fundamental combustion and explosion characteristics will lead to a higher potential of explosion hazard especially in industries. In this study, a gas explosion in a confined space is considered. An experimental approach using the 20 L closed spherical vessel is adopted to investigate the explosion characteristics of the premixed biogas/air mixtures. The factors (i.e. equivalence ratio (ER), CO2 concentration and initial pressure) contributed to the premixed biogas/air explosion characteristics (i.e. the explosion overpressure (Pex), maximum explosion overpressure (Pmax), the maximum rate of pressure rise ((dP/dt)max) and gas deflagration index (KG) was evaluated. From the results, it was found that the premixed biogas/air having 40% vol/vol CO2 was the most severe when exploded at a slightly rich concentration (ER = 1.2) with Pex, Pmax and (dP/dt)max of 8.50 bar, 9.08 bar and 120.00 bar/ms respectively. Besides, the evaluation of CO2 concentration in the premixed biogas/air mixture also showed that the mixture having 45% vol/vol CO2 at ER of 1.2 was found to be the least severe when exploded with Pex, Pmax and (dP/dt)max of 7.60 bar, 8.05 bar and 82.25 bar/ms respectively. This was due to the physical effect of CO2 and thermal-diffusive instability. Further, the premixed biogas/air mixture was also found to be the most severe when exploded at an initial pressure of 1.1 bar with Pex, Pmax and (dP/dt)max of 9.90 bar, 10.90 bar and 1922.50 bar/ms respectively. This was due to the fewer spaces between molecules, higher reaction rate as well as due to the role of thermal-diffusive instability. This study also shows that the premixed biogas/air mixture at ER ranging from 0.8 to 1.5 to fall into St-3 hazard class that was the most severe when exploded. Verification of the Pmax obtained from the experimental results was also conducted using the FLame ACcelaration Simulator (FLACs) software. Results showed that the Pmax was found to be within the ± 30% limit of discrepancy and is considered satisfactory. The compared Pmax from this study with published data from literature also shows a comparable trend. As a conclusion, it shows that the ER, CO2 concentration and the initial pressure of the premixed biogas/air mixture has a significant impact on its explosion characteristics, which can lead to a catastrophic explosion.
610 2 0 _aFaculty of Chemical and Natural Resources Engineering
_xDissertations
650 0 _aUniversities and colleges
_xDisertations
650 0 _aTheses
942 _2lcc
_cTHESIS