| 1. |
- Naqvi, Muhammad, et al.
(författare)
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Gasification integrated with small chemical pulp mills for fuel and energy production
- 2017
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Ingår i: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY. - : Elsevier. ; 142, s. 977-983
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Konferensbidrag (refereegranskat)abstract
- Pulp mills without black liquor recovery cycle could play a major role in employing black liquor gasification (BLG) to produce transport fuels. In conventional chemical pulp mills, black liquor is burnt in recovery boilers to generate steam and electricity to meet energy demands. The inorganic chemicals are reused for the digestion process. However, the energy content and inorganic chemicals are not recovered in small scale pulp mills especially in the developing countries which do not employ recovery cycle. This study investigates the potential of synthetic natural gas (SNG) production by integrating BLG island with a reference pulp mill without chemical recovery cycle. The improvements in overall energy efficiency are evaluated using performance indicators such as biofuel production potential, integrated system's efficiency, and energy ratios. The oxygen-blown circulating fluidized bed (CFB) gasification with direct causticization is integrated with reference pulp mill. The results showed considerable SNG production without external biomass import. However to compensate total electricity deficit, the electricity will be imported from the grid. There is a substantial CO2 abatement potential of combining CO2 capture using seloxol absorption, and CO2 mitigation from SNG by replacing gasoline. (C) 2017 The Authors. Published by Elsevier Ltd.
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| 2. |
- Naqvi, Muhammad Raza, 1983-, et al.
(författare)
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Off-grid electricity generation using mixed biomass compost: : A scenario-based study with sensitivity analysis
- 2017
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 201, s. 363-370
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study is to investigate the viability of waste gasification based off-grid electricity gener- ation utilizing mixed biomass composts (mixture of rice hulls with cow/poultry manure compost). The economic viability is studied on the different scenarios with considerations of (1) levels of electricity demand and utilization, (2) costs of variable biomass mix, (3) combined domestic and cottage industry business model, and (4) influence of governmental investments. The levelized cost of electricity (LCOE) is used as an indicator to measure the competitiveness of gasification based off-grid electricity genera- tion. The plant loading and the capacity factor have been used to assess the impacts of different scenarios. A sensitivity analysis of key parameters based on variations in annual operational hours, plant efficiency, plant cost and biomass supply cost is conducted. Based on levels of electricity demand and utilization, the LCOE ranged between 40 US cents/kW h and 29 US cents/kW h based on the plant loading and the capac- ity factor. The business revenue would not change considerably despite better plant utilization and reduced levelized cost of electricity if all the consumers, both basic or medium, are charged with the flat tariff. The part load operation will be costly despite considerably low capital investment per kW in com- parison with PV or solar based plants. There is a large potential of off-grid electricity generation but the estimated off-grid electricity price is found to be higher in all scenarios than average grid-based electric- ity tariff. Moreover, the challenges for the implementation of the real off-grid electricity generation plant are discussed.
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| 3. |
- Naqvi, Salman Raza, et al.
(författare)
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Catalytic Pyrolysis Of Botryococcus Braunii (microalgae) Over Layered and Delaminated Zeolites For Aromatic Hydrocarbon Production
- 2017
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Ingår i: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY. - : ELSEVIER SCIENCE BV. ; , s. 381-385
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Konferensbidrag (refereegranskat)abstract
- Botryococcus braunii (B. Braunii) is considered as due to its high capability of large aromatic contents, prominent green microalgae as a renewable energy resource. The aim and novelty of this work is to exploit the pyrolysis characteristics of microalgae with layered and delaminated zeolites using Py-GC/MS. No catalyst and catalytic pyrolysis was compared to evaluate product components formed. Further, the catalytic pyrolysis of botryococcus braunii was carried out in the presence of two zeolites with different pore topology and acidity. The results from non-catalytic microalgae pyrolysis were compared to catalytic pyrolysis together with different catalysts to biomass ratios for aromatic hydrocarbons production. Py-GC/MS results showed the aromatic hydrocarbon production (area%) was significantly improved from zeolite catalytic pyrolysis than non-catalytic pyrolysis. The increase in catalyst to biomass ratio (3:1 and 5:1) resulted in higher aromatic hydrocarbon production. As the catalyst to biomass ratio increased, it is observed that aromatic hydrocarbon content increased as compared to low catalyst to biomass ratio. In addition, ITQ-2 zeolite generated higher aromatic hydrocarbons. This might be due to better pore structure and acidity of delaminated structure as compared to layered structure. This delaminated topology enhances the reactant diffusion and reduces the secondary cracking.
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| 4. |
- Qureshi, Abdul Sattar, et al.
(författare)
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Fruit waste to energy through open fermentation
- 2017
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Ingår i: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY. - Amsterdam : Elsevier. ; 142, s. 904-909
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Konferensbidrag (refereegranskat)abstract
- This study aims to examine the nonsterilized fermentation conditions for coproduction of pectinases and lipase enzymes using several fruit wastes as an energy source. Thermophilic fungal strain, Penicillium expansum CM,1 39671 was used as a fermenting strain. The effect of process conditions including; nitrogen sources, pH, temperature, time and moisture contents, on the production of both enzymes were studied. The highest activities of pectinase and lipase (2817, 1870 U/g dry substrate) enzymes were found with orange peel feedstock, whereas the lowest activities of 1662 U/g and 1266 U/g were found with banana peel and papaya peel feedstocks respectively. Overall, pectinase showed higher enzymatic activities than lipase enzymes, both having similar increasing and decreasing trends, at all studied conditions. The optimum process conditions of peptone as a nitrogen source, pH 7, 40 degrees C, 5 days and 70% moisture contents, were found to show highest enzymatic activities for both enzymes. The orange peel feedstock showed no significant difference in both enzymes' activities at sterilized and nonnotarized process conditions. Pectinase and lipase enzymes showed (13791 U/g) and (8114 U/g) for sterilized and (14091 U/g) and (8324 U/g) for nonnotarized process conditions respectively. In addition, the fungal strains also produce bacteriocin-like compounds that could inhibit microbial growth. These findings will help to design and develop robust, cost-effective and less energy intensive enzyme production processes and consequently an efficient fruit waste to energy system through open fermentation. (C) 2017 The Authors. Published by Elsevier Ltd.
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| 5. |
- Salman, Chaudhary Awais, 1986-, et al.
(författare)
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A polygeneration process for heat, power and DME production by integrating gasification with CHP plant : Modelling and simulation study
- 2017
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Ingår i: Proceedings of the 9th International Conference on Applied Energy. - Amsterdam : Elsevier. ; 142, s. 1749-1758
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Konferensbidrag (refereegranskat)abstract
- Biofuels are a good substitute for the transport sector petroleum fuels to minimize carbon footprint and greenhouse gases emissions. Di-Methyl Ether (DME) is one such alternative with properties similar to liquefied petroleum gas but with lower SOx, NOx, and particulate emissions. In this work, a polygeneration process, integrating an existing combined heat and power (CHP) plant with biomass gasification to synthesize DME, is proposed and modelled. Process integration is based on a hypothesis that the CHP plant provides the necessary heat to run the co-located gasification plant for DME synthesis and the waste heat from the gasification process is recovered and transferred to the CHP plant. The feed for gasification is taken as refuse derived fuel (RDF) instead of conventional wood derived biomass. The process integration leads to higher overall combined efficiency (up to 71%) which is greater than stand-alone efficiencies (up to 63%) but lower than stand-alone CHP plant efficiency (73.2%). The further technical evaluation shows that the efficiency of the polygeneration process is depends heavily on the gasifier capacity integrated with the existing CHP plant and also on the conversion route selected for DME synthesis i.e. recycling of unconverted syngas to the DME reactor or transferring it to the boiler of the CHP plant. The simulation results also indicate that once-through conversion yields less DME than recycling, but at the same time, once-through conversion affects the district heat and electric power production of the CHP plant lesser than by using the recycling route.
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| 6. |
- Salman, Chaudhary Awais, et al.
(författare)
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Impact of retrofitting existing combined heat and power plant with polygeneration of biomethane : A comparative techno-economic analysis of integrating different gasifiers
- 2017
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Ingår i: Energy Conversion and Management. - : Elsevier. - 0196-8904 .- 1879-2227. ; 152, s. 250-265
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Tidskriftsartikel (refereegranskat)abstract
- It is vital to identify and evaluate the optimal gasifier configuration that could be integrated with existing or new combined heat and power (CHP) plants to maximize the utilization of boiler operating capacity during off-peak hours with minimal effect on the boiler performance. This study aims to identify technically and economically most suitable gasification configuration and the reasonable operational limits of a CHP plant when integrated with different types of gasifiers. The selected gasifiers for the study are, (i) indirectly heated dual fluidized bed gasifier (DFBG), (ii) directly heated circulating fluidized bed gasifier (CFBG), and (iii) entrained flow gasifier (EFG). The gasifiers are selected on their ability to produce high-quality syngas from waste refused derived fuel (RDF). The syngas from the gasifiers is utilized to produce biomethane, whereas the heat and power from the CHP plant are consumed to run the gasification process. A detailed techno-economic analysis is performed using both flexible capacity and fixed capacity gasifiers and integrated with the CHP plant at full load. The results reveal that the integration leads to increase in operating time of the boiler for all gasifier configurations. The indirectly heated DFBG shows the largest biomethane production with less impact on the district heat and power production. Extra heat is available for biomethane production when the district heat and biomethane are prioritized, and the electric power is considered as a secondary product. Furthermore, the economic indicators reflect considerable dependency of integrated gasification performance on variable prices of waste biomass and biomethane.
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