| 1. |
- Soam, Shveta, 1987-, et al.
(författare)
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Life cycle assessment of rice straw utilization practices in India
- 2017
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 228, s. 89-98
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study is to find potential utilization practice of rice straw in India from an environmental perspective. Life cycle assessment (LCA) is conducted for four most realistic utilization practices of straw including: (1) incorporation into the field as fertilizer (2) animal fodder (3) electricity (4) biogas. The results show that processing of 1 ton straw to electricity and biogas resulted in net reduction of 1471 and 1023 kg CO2 eq., 15.0 and 3.4 kg SO2 eq. and 6.7 and 7.1 kg C2H6 eq. emissions in global warming, acidification and photochemical oxidation creation potential respectively. Electricity production from straw replaces the coal based electricity and resulted in benefits in most of the environmental impacts whereas use as an animal fodder resulted in eutrophication benefits. The burning of straw is a harmful practice of managing straw in India which can be avoided by utilizing straw for bioenergy.
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| 2. |
- Kapoor, Manali, et al.
(författare)
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Impact of Conditioning Prior to Dilute Acid Deconstruction of Biomass for the Production of Fermentable Sugars
- 2017
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 5:5, s. 4285-4292
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Tidskriftsartikel (refereegranskat)abstract
- Cost of cellulases is a major impediment in commercialization of cellulosic ethanol. To reduce the enzyme doses for the production of fermentable sugars from rice straw (RS), a series of alkali conditioning experiments were conducted prior to dilute acid (DA) pretreatment. This approach resulted in removal of a majority of extractives, ash, acetic acid, and part lignin, and thus resulted in lowering pseudolignin formation thereby increasing enzymatic hydrolysis yields. Glucan hydrolysis of 69.8%, 74.0%, and 83.5% was obtained at 10 wt % water insoluble solid (WIS) using 8 FPU enzyme/g WIS of biomass conditioned using 0.2, 0.4, and 0.5 wt % alkali prior to pretreatment, which is 14–37% higher than the control (61.0%). The overall sugar recovery in these experiments were 69.2%, 70.2%, and 68.5% at 15 wt % WIS resulting in a sugar concentration greater than 120 g/L, which in turn can produce approximately 5–6% w/v ethanol concentration in fermentation broth. It was found that this approach resulted in a decrease of the enzyme consumption vis-a-vis the conventional process by 46.4% to recover the same amount of sugars. This lowering of enzyme consumption has resulted in net savings, after taking into account the cost of alkali used in the conditioning steps.
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| 3. |
- Kapoor, M., et al.
(författare)
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Pilot scale dilute acid pretreatment of rice straw and fermentable sugar recovery at high solid loadings
- 2017
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Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 224, s. 688-693
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to study the dilute acid pretreatment of rice straw (RS) and fermentable sugar recovery at high solid loadings at pilot scale. A series of pretreatment experiments were performed on RS resulting in >25 wt% solids followed by enzymatic hydrolysis without solid-liquid separation at 20 and 25 wt% using 10 FPU/g of the pretreated residue. The overall sugar recovery including the sugars released in pretreatment and enzymatic hydrolysis was calculated along with a mass balance. Accordingly, the optimized conditions, i.e. 0.35 wt% acid, 162 °C and 10 min were identified. The final glucose and xylose concentrations obtained were 83.3 and 31.9 g/L respectively resulting in total concentration of 115.2 g/L, with a potential to produce >50 g/L of ethanol. This is the first report on pilot scale study on acid pretreatment of RS in a screw feeder horizontal reactor followed by enzymatic hydrolysis at high solid loadings.
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| 4. |
- Kumar, Devesh, et al.
(författare)
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Performance analysis of meta-material based bow-tie shaped fractal antenna for THz application
- 2017
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Ingår i: Proceedings of the 7th International Conference Confluence 2017 on Cloud Computing, Data Science and Engineering. - : IEEE. - 9781509035199 ; , s. 764-769
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Konferensbidrag (refereegranskat)abstract
- This paper presents design and analysis of meta-material based bowtie-shaped fractal antenna for the frequency range of l.l-l.8 THz for futuristic Terahertz applications. A meta-material-inspired structure isinserted on ground plane to enhance overall performance of the proposed design. A comparative analysis of various iterated designs has been carried out in detail. Performance parameters e.g. return loss, antenna gain, radiation efficiency, radiation pattern are presented and discussed. Simulated resultsshow the multiband nature of designed antennas. Maximum gain of 6.59 dB and return loss of −21.00 dB are obtained at 1.5455 THz and 1.1787 THz respectively. HFSS simulation software is used for simulation of the designs.
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| 5. |
- Ruchi, Gaur, et al.
(författare)
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Bench scale dilute acid pretreatment optimization for producing fermentable sugars from cotton stalk and physicochemical characterization
- 2016
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Ingår i: Industrial crops and products (Print). - : Elsevier BV. - 0926-6690 .- 1872-633X. ; 83, s. 104-112
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Tidskriftsartikel (refereegranskat)abstract
- Cotton stalk is a holocellulose rich, inexpensive agricultural residue available in surplus without any competitive uses neither as food nor as animal fodder. These aspectshold high potential for cotton stalk as a biomass to be suitable for ethanol production. Dilute acid pretreatment conditions on bench scale have been optimized for cotton stalk by Response Surface Methodology (RSM) using Central Composite Design (CCD). Effect of four pretreatment process variables viz. temperature, acid concentration, time of reaction and stirring speed has been optimized for maximum enzymatic sugar release during the subsequent enzymatic saccharification. Under the optimized pretreatment conditions, i.e., temperature: 157. °C, acid concentration: 1.07% (w/w),and time: 20 min, enzymatic sugar releasewas found to be 684 mg/g of dry pretreated biomass. A correlation of hemicellulose removal and inhibitor formation with combined severity factor (CSF) was drawn. Mass balance carried out for the pretreatment step under optimized conditions resulted in 68.35 and 8.31% of xylose and glucose saccharificationyieldsrespectively. Subsequent enzymatic saccharification yieldsofglucose and xylose were 93.56 and 19.93% respectively. The overall saccharification yield integrating pretreatment and enzymatic hydrolysis of cotton stalk was 91.06%. Physicochemical characterization of native and pretreated biomass was carried out by compositional analysis, FT-IR and XRD revealing significant changes in biomassproperties responsible for improved saccharification efficiency.
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| 6. |
- Soam, Shveta, 1987-, et al.
(författare)
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Global warming potential and energy analysis of second generation ethanol production from rice straw in India
- 2016
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 184, s. 353-364
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Tidskriftsartikel (refereegranskat)abstract
- The environmental sustainability of cellulosic ethanol production from rice straw in India is conducted using life cycle assessment (LCA). Greenhouse gas (GHG) emissions, net energy ratio (NER) and net energy balance (NEB) are studied for ethanol production system using two diverse pretreatment technologies, i.e. dilute acid (DA) and steam explosion (SE) followed by separate hydrolysis and fermentation. 1 ton of rice straw is the reference flow of study and 1 MJ transportation fuel is the functional unit while comparing the results with gasoline. The inventory data is collected based on several experiments conducted at our pilot plant and is a novel contribution to country specific LCA. Using DA and SE, the ethanol yields from the processing of 1 ton straw are 239 and 253 L and life cycle GHG emissions are 292 and 288 kg CO2 eq./ton straw respectively. The results indicated that production of enzyme used in hydrolysis is the major contributor to GHG emissions in both DA (54%) and SE (57%) methods of ethanol production. The net energy input during the life cycle of ethanol is 1736 and 1377 MJ/ton straw in DA and SE respectively. The major GHG emissions and energy benefits are obtained using lignin produced in the plant to generate electricity resulting in displacement of the coal based electricity. With a higher xylose recovery in the SE, it gives larger amount of ethanol and also generates more surplus electricity. Enzyme production and its use are identified as GHG emission and energy consumption hotspot in the ethanol production process. While comparing the results with gasoline, DA and SE resulted in a reduction of 77 and 89% GHG emissions and NER of 2.3 and 2.7 respectively. The E5 blending would reduce GHG emissions by 4.3% (DA) and 4.8% (SE) whereas; E20 blend would lead to a reduction of 17.4% (DA) and 18.8% (SE) respectively. Sensitivity analysis indicates that with every 12.5% increase in the price of rice straw from the base case, there is a 2.3% increase in GHG emissions and vice versa. 1 FPU/g WIS increase during hydrolysis gives 2.9% increase in ethanol production, but at the same time there is an increase of 5% emissions from enzyme production. The results of the study conclude that cellulosic ethanol production technology in India is sustainable from GHG reduction and energy efficiency perspective.
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| 7. |
- Soam, Shveta, 1987-, et al.
(författare)
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Life cycle assessment and life cycle costing of conventional and modified dilute acid pretreatment for fuel ethanol production from rice straw in India
- 2018
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 197:1, s. 732-741
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Tidskriftsartikel (refereegranskat)abstract
- Dilute acid (DA) pretreatment results in the formation of inhibitory compounds and pseudo-lignin along with the burden of unnecessary materials like ash, extractive, lignin or their condensed products that reduces the conversion efficiency of cellulose to monomeric sugar. Indian Oil Corporation Limited (IOCL) has developed a modified pretreatment (MP) in order to reduce the enzyme dosage during ethanol production. This method uses extraction of biomass in water and varying alkali concentration of 0.2, 0.4 and 0.5%, prior to pretreatment as a strategy to reduce the enzyme dosage and improve the ethanol yield. The environmental and economic impact of these MP scenarios in comparison with conventional pretreatment (CP) is studied. The ethanol production increases from 218 to 267 L using MP. The introduction of extraction step prior to DA pretreatment fulfills the objective of reducing enzyme dosage by 23–39%. However, overall life cycle assessment (LCA) results revealed that performance of MP2, MP3 and MP4 is on a negative side in all the environmental impact categories as compared to CP due to the use of alkali, where a huge amount of emissions are released during the production stage. Overall, MP1 using water as a media for extraction is the most environmentally suitable pretreatment process for ethanol production. Life cycle costing (LCC) results showed that cost of 1 L ethanol production could be lowered down from 0.87 to 0.70 United States Dollar (USD) using MP1 scenario. From an environment and economic perspective, it is recommended to use only water as an extraction media for biomass, as this can reduce the enzyme dosage, emissions and cost.
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