| 1. |
- Ademuyiwa, Adesoji O., et al.
(author)
-
Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
-
In: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
-
Journal article (peer-reviewed)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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| 2. |
- Anees, Hafiz Muhammad, et al.
(author)
-
A mathematical model-based approach for DC multi-microgrid performance evaluations considering intermittent distributed energy resources, energy storage, multiple load classes, and system components variations
- 2021
-
In: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; 9, s. 1919-1934
-
Journal article (peer-reviewed)abstract
- The efficiency of DC microgrid needs investigation from a smart grid perspective, since their spread has expected to prevail in comparison with AC counterparts. Furthermore, there is a need to address the limitations (majorly to cater the intermittency of distributed energy resources (DERs) as well as the time dependency of systematic parameters etc.) in previous model and propose a new mathematical model to evaluate system efficiency for given parameters and scenarios. The core focus of current study aims at formulation of an improved (composite) mathematical model, that is capable of bridging issues and serve as a tool to address requirements of future DC systems including microgrids (MGs) and multi-microgrids (MMGs). This research work offers such a mathematical model that consists of 3D matrices based on newly derived set of discrete time dependent equations, which evaluates the system efficiency of residential DC-MMGs. Each DC-MG is embedded with intermittent DERs, storage, components (with efficiency variations), and multi-class load (with discrete time dependency), for evaluation across worst, normal, and best scenarios. A comprehensive sensitivity analysis across various cases and respective scenarios are also presented to evaluate overall system performance. Also, the impacts of system parameters on various system variables, states, and overall system efficiency have presented in this paper.
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| 3. |
- Arslan, Muhammad, et al.
(author)
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Impact of Varying Load Conditions and Cooling Energy Comparison of a Double-Inlet Pulse Tube Refrigerator
- 2020
-
In: Processes. - : MDPI. - 2227-9717. ; 8:3
-
Journal article (peer-reviewed)abstract
- Modeling and optimization of a double-inlet pulse tube refrigerator (DIPTR) is very difficult due to its geometry and nature. The objective of this paper was to optimize-DIPTR through experiments with the cold heat exchanger (CHX) along the comparison of cooling load with experimental data using different boundary conditions. To predict its performance, a detailed two-dimensional DIPTR model was developed. A double-drop pulse pipe cooler was used for solving continuity, dynamic and power calculations. External conditions for applicable boundaries include sinusoidal pressure from an end of the tube from a user-defined function and constant temperature or limitations of thermal flux within the outer walls of exchanger walls under colder conditions. The results of the system's cooling behavior were reported, along with the connection between the mass flow rates, heat distribution along pulse tube and cold-end pressure, the cooler load's wall temp profile and cooler loads with varied boundary conditions i.e. opening of 20% double-inlet and 40-60% orifice valves, respectively. Different loading conditions of 1 and 5W were applied on the CHX. At 150 K temperature of the cold-end heat exchanger, a maximum load of 3.7 W was achieved. The results also reveal a strong correlation between computational fluid dynamics modeling results and experimental results of the DIPTR.
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| 4. |
- Danish, Muhammad, et al.
(author)
-
Characterization of South Asian agricultural residues for potential utilization in future 'energy mix'
- 2015
-
In: Energy Procedia. - : Elsevier. ; 75, s. 2974-2980
-
Conference paper (peer-reviewed)abstract
- This paper characterizes various locally available agricultural residues in South Asian region to evaluate their potential as feedstock for renewable energy production and contributing toward solving energy crisis and environmental issues. The thermo-chemical characterization has been performed in order to determine if the residues have potential to be used in biomass conversion technologies producing combined heat and power. The characterization methods for comparing different agricultural residues include proximate and ultimate analysis, heating value, ash content, thermo gravimetric analysis (TGA) and structural composition analysis (SCA). Widely available agricultural wastes in South Asian region were selected for the characterization i.e. bagasse, almond shell, corn cob, cotton stalks, wheat straw, sawdust, corn leaf, rice husk, rice straw, and corn straw. The analysis showed that the corn cob had the highest moisture content that will result in low energy efficiency of the thermal conversion technology due to energy requirement for drying. Whereas almond shell had the lowest moisture content. Ash and volatile contents were found to be highest in rice straw and almond shell respectively. The thermo gravimetric analysis showed that most of the agricultural residues can be easily decomposed and represent potential feedstock for biomass flexible combined heat and power systems through pyrolysis or gasification.
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| 5. |
- Farooq, Muhammad, et al.
(author)
-
Thermodynamic Performance Analysis of Hydrofluoroolefins (HFO) Refrigerants in Commercial Air-Conditioning Systems for Sustainable Environment
- 2020
-
In: Processes. - : MDPI. - 2227-9717. ; 8:2
-
Journal article (peer-reviewed)abstract
- Global warming is one of most severe environmental concerns that our planet is facing today. One of its causes is the previous generation of refrigerants that, upon release, remain in the atmosphere for longer periods and contribute towards global warming. This issue could potentially be solved by replacing the previous generation's high global warming potential (GWP) refrigerants with environmentally friendly refrigerants. This scenario requires an analysis of new refrigerants for a comparison of the thermodynamic properties of the previously used refrigerants. In the present research, a numerical study was conducted to analyze the thermodynamic performance of specifically low GWP hydrofluoroolefens (HFO) refrigerants for an actual vapor compression refrigeration cycle (VCRC) with a constant degree of 3 K superheat. The output parameters included the refrigeration effect, compressor work input, the coefficient of performance (COP), and the volumetric refrigeration capacity (VRC), all of which were calculated by varying the condenser pressure from 6 to 12 bars and vapor pressure from 0.7 to 1.9 bars. Results showed that R1234ze(Z) clearly possessed the desired thermodynamic performance. The drop in refrigeration effect for R1234ze(Z) was merely 14.6% less than that of R134a at a 12 bar condenser pressure; this was minimum drop among candidate refrigerants. The drop in the COP was the minimum for R1234ze(Z)-5.1% less than that of R134a at a 9 bar condenser pressure and 4.7% less than that of R134a at a 1.9 bar evaporator pressure, whereas the COP values of the other refrigerants dropped more drastically at higher condenser pressures. R1234ze(Z) possessed favorable thermodynamic characteristics, with a GWP of 7, and it can serve as an alternative refrigerant for refrigeration systems for a sustainable environment.
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| 6. |
- Hameed, Zeeshan, et al.
(author)
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A Comprehensive Review on Thermal Coconversion of Biomass, Sludge, Coal, and Their Blends Using Thermogravimetric Analysis
- 2020
-
In: Journal of Chemistry. - : Hindawi Publishing Corporation. - 2090-9063 .- 2090-9071. ; 2020
-
Research review (peer-reviewed)abstract
- Lignocellulosic biomass is a vital resource for providing clean future energy with a sustainable environment. Besides lignocellulosic residues, nonlignocellulosic residues such as sewage sludge from industrial and municipal wastes are gained much attention due to its large quantities and ability to produce cheap and clean energy to potentially replace fossil fuels. These cheap and abundantly resources can reduce global warming owing to their less polluting nature. The low-quality biomass and high ash content of sewage sludge-based thermal conversion processes face several disadvantages towards its commercialization. Therefore, it is necessary to utilize these residues in combination with coal for improvement in energy conversion processes. As per author information, no concrete study is available to discuss the synergy and decomposition mechanism of residues blending. The objective of this study is to present the state-of-the-art review based on the thermal coconversion of biomass/sewage sludge, coal/biomass, and coal/sewage sludge blends through thermogravimetric analysis (TGA) to explore the synergistic effects of the composition, thermal conversion, and blending for bioenergy production. This paper will also contribute to detailing the operating conditions (heating rate, temperature, and residence time) of copyrolysis and cocombustion processes, properties, and chemical composition that may affect these processes and will provide a basis to improve the yield of biofuels from biomass/sewage sludge, coal/sewage sludge, and coal/biomass blends in thermal coconversion through thermogravimetric technique. Furthermore, the influencing factors and the possible decomposition mechanism are elaborated and discussed in detail. This study will provide recent development and future prospects for cothermal conversion of biomass, sewage, coal, and their blends.
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| 7. |
- Hussain, Arif, et al.
(author)
-
Methoxy-methylheptane as a cleaner fuel additive : An energy- and cost-efficient enhancement for separation and purification units
- 2021
-
In: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; :9, s. 1632-1646
-
Journal article (peer-reviewed)abstract
- Environmental protection agencies have begun imposing stringent regulations on the existing refineries to control the levels of gasoline additives. In this context, a novel compound, 2-methoxy-2-methylheptane (MMH), had drawn attention as fuel additive for cleaner combustion. The conventional process of MMH production features three distillation columns in a direct sequence. These columns are used to maintain the required product purities and to utilize the unreacted reactants through recycling streams. The distillation system of the existing MMH plant can afford significant energy savings, leading to a reduction in the total annual costs (TAC). The aim of this investigation is to demonstrate that the reported conventional process can be significantly enhanced by modifying the design and operational parameters and by replacing two distillation columns with an intensified dividing wall column (DWC) configuration. The DWC design is further optimized using several algorithms such as the modified coordinate method (MCD), robust particle swarm paradigm (PSP), and firefly (FF) with nonlinear constraints. Compared to conventional process, the optimized DWC resulted in 24% and 11.5% savings in the plant operating and total annual costs, respectively.
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| 8. |
- Jamil, Asif, et al.
(author)
-
Polyetherimide-Montmorillonite Nano-Hybrid Composite Membranes : CO2 Permeance Study via Theoretical Models
- 2020
-
In: Processes. - : MDPI. - 2227-9717. ; 8:1
-
Journal article (peer-reviewed)abstract
- The incorporation of aminolauric acid modified montmorillonite (f-MMT) in polyetherimide (PEI) has been implemented to develop hollow fibre nano-hybrid composite membranes (NHCMs) with improved gas separation characteristics. The aforementioned characteristics are caused by enhanced f-MMT spatial dispersion and interfacial interactions with PEI matrix. In this study, existing gas permeation models such as, Nielsen, Cussler, Yang-Cussler, Lape-Cussler and Bharadwaj were adopted to estimate the dispersion state of f-MMT and to predict the CO2 permeance in developed NHCMs. It was found out that the average aspect ratio estimated was 53, with 3 numbers of stacks per unit tactoid, which showed that the intercalation f-MMT morphology is the dominating dispersion state of filler in PEI matrix. Moreover, it was observed that Bharadwaj model showed the least average absolute relative error (%AARE) values till 3 wt. % f-MMT loading in the range of +/- 10 for a pressure range of 2 to 10 bar. Hence, Bharadwaj was the best fit model for the experimental data compared to other models, as it considers the platelets orientation.
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| 9. |
- Kazmi, Bilal, et al.
(author)
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Process system analysis on oil processing facility and economic viability from oil well-to-tank
- 2021
-
In: SN Applied Sciences. - : Springer Science and Business Media LLC. - 2523-3963 .- 2523-3971. ; 3:7
-
Journal article (peer-reviewed)abstract
- Hydrocarbon processing from extraction to the final product is an important aspect that needs an optimised technology for consumption-led market growth. This study investigated real data from the oil processing facility and analysed the simulation model for the entire crude oil processing unit based on the process system engineering aspect using Aspen HYSYS. The study mainly emphasises the process optimisation in processing the hydrocarbon for the maximum yield of the product with less energy consumption. The investigation also includes a thorough economic analysis of the processing facility. The datasets for oil properties are obtained from a modern petroleum refinery. The investigation comprises of varying transient conditions, such as well shutdowns using three oil reservoirs (low, intermediate, and heavy oil). The impact of various conditions, including process heating, well shutdown, oil combinations, presence of water on the production, is analysed. The results indicate that the factors involving crude oil processing are significantly affected by the process conditions, such as pressure, volume, and temperature. The vapour recovery unit is integrated with the oil processing model to recover the separator's gas. The optimisation analysis is performed to maximise the liquid recovery with Reid vapour pressure of 7 and minimum water content in oil around 0.5%. Economic analysis provided an overall capital cost of $ 9.7 x 10(6) and an operating cost of $2.1 x 10(6) for the process configuration. The model results further investigate the constraints that maximise the overall energy consumption of the process and reduce the operational cost.
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| 10. |
- Kazmi, Bilal, et al.
(author)
-
Thermodynamic and economic assessment of cyano functionalized anion based ionic liquid for CO2 removal from natural gas integrated with, single mixed refrigerant liquefaction process for clean energy
- 2022
-
In: Energy. - : Pergamon Press. - 0360-5442 .- 1873-6785. ; 239
-
Journal article (peer-reviewed)abstract
- The study proposes a novel integrated process in which ionic liquid is utilized to control carbon dioxide (CO2) emissions from the natural gas combined with a single mixed refrigerant-based liquefaction process to assist safe transportation over long distances providing a sustainable and cleaner energy. Commercially amines are utilized for CO2 sequestration, but amines entail energy-intensive regeneration with elevated process costs. The present study offers a solvent screening mechanism based on important parameters such as heat of dissolution, viscosity, selectivity, working capacity, vapor pressure, corrosivity, and toxicity. The selected solvents' performance is computed by sensitivity analysis suggesting imidazolium-based cation 1-hexyl-3-methylimidazolium[Hmim] functionalized with tricyanomethanide(tcm) as anion a potential natural gas sweetening solvent in comparison with commercially used solvent monoethanoloamine(MEA), conventional ILs 1-butyl-3-methylimidazolium hexa-fluorophosphate [Bmim][Pf(6)] and 1-butyl-3-methylimidazolium methyl sulfate [Bmim][MeSO4]. The obtained sweet gas is liquefied using a single mixed refrigerant-based process providing 0.99 mol fraction of liquefied CH4 with less overall specific compression power requirement of 0.41 kW/kg of natural gas. Moreover, an exergy analysis demonstrates that the [Hmim][tcm] based process has lower total exergy destruction of 7.49 x 10(3) kW and is found to utilize less overall specific energy consumption 0.49 kWh/kg of NG in contrast to other studied solvents. Furthermore, a detailed economic analysis establishes [Hmim][tcm]-based CO2 integrated with liquefaction technology offers 50.7%, 74.4%, and 85.8% of total annualized cost (TAC) savings compared with the MEA-amim][Pf(6)]-, and [Bmim][MeSO4], respectively. Hence, [Hmim][tcm] for CO2 removal and integration with liquefaction process will incur unit cost based on the total annualized cost to be $2.2 x 10(4)/kmol of purified NG.
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| 11. |
- Manzoor, Numair, et al.
(author)
-
RETRACTED: Experimental Study of CO2 Conversion into Methanol by Synthesized Photocatalyst (ZnFe2O4/TiO2) Using Visible Light as an Energy Source
- 2020
-
In: Catalysts. - : MDPI. - 2073-4344. ; 10:2
-
Journal article (peer-reviewed)abstract
- Ozone layer depletion is a serious threat due to the extensive release of greenhouse gases. The emission of carbon dioxide (CO2) from fossil fuel combustion is a major reason for global warming. Energy demands and climate change are coupled with each other. CO2is a major gas contributing to global warming; hence, the conversion of CO2 into useful products such as methanol, formic acid, formaldehyde, etc., under visible light is an attractive topic. Challenges associated with the current research include synthesizing a photocatalyst that is driven by visible light with a narrow band gap range between 2.5 and 3.0 eV, the separation of a mixed end product, and the two to three times faster recombination rate of an electron–hole pair compared with separation over yield. The purpose of the current research is to convert CO2 into useful fuel i.e., methanol; the current study focuses on the photocatalytic reduction of CO2into a useful product. This research is based on the profound analysis of published work, which allows the selection of appropriate methods and material for this research. In this study, zinc ferrite (ZnFe2O4) is synthesized via the modified sol–gel method and coupled with titanium dioxide (TiO2). Thereafter, the catalyst is characterized by Fourier transform infrared (FTIR), FE-SEM, UV–Vis, and XRD characterization techniques. UV–Vis illustrates that the synthesized catalyst has a low band gap and utilizes a major portion of visible light irradiation. The XRD pattern was confirmed by the formation of the desired catalyst. FE-SEM illustrated that the size of the catalyst ranges from 50 to 500 nm and BET analysis determined the surface area, which was 2.213 and 6.453 m2/g for ZnFe2O4 and ZnFe2O4/TiO2, respectively. The continuous gas flow photoreactor was used to study the activity of the synthesized catalyst, while titanium dioxide (TiO2) has been coupled with zinc ferrite (ZnFe2O4) under visible light in order to obtain the maximum yield of methanol as a single product and simultaneously avoid the conversion of CO2 into multiple products. The performance of ZnFe2O4/TiO2was mainly assessed through methanol yield with a variable amount of TiO2 over ZnFe2O4 (1:1, 1:2, 2:1, 1:3, and 3:1). The synthesized catalyst recycling ability has been tested up to five cycles. Finally, we concluded that the optimum conditions for maximum yield were found to be a calcination temperature of ZnFe2O4at 900 °C, and optimum yield was at a 1:1 w/w coupling ratio of ZnFe2O4/TiO2. It was observed that due to the enhancement in the electron–hole pair lifetime, the methanol yield at 141.22 μmol/gcat·h over ZnFe2O4/TiO2was found to be 7% higher than the earlier reported data.
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| 12. |
- Naqvi, Muhammad, et al.
(author)
-
Gasification integrated with small chemical pulp mills for fuel and energy production
- 2017
-
In: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY. - : Elsevier. ; 142, s. 977-983
-
Conference paper (peer-reviewed)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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| 13. |
- Naqvi, Muhammad, et al.
(author)
-
Polygeneration system integrated with small non-wood pulp mills for substitute natural gas production
- 2018
-
In: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 224, s. 636-646
-
Journal article (peer-reviewed)abstract
- This study aims to examine the potential substitute natural gas (SNG) production by integrating black liquor gasification (BLG) island with a small wheat straw-based non-wood pulp mills (NPM), which do not employ the black liquor recovery cycle. For such integration, it is important to first build knowledge on expected improvements in an overall integrated non-wood pulp mill energy system using the key performance indicators. O2-blown circulating fluidized bed (CFB) gasification with direct causticization is integrated with a reference small NPM to evaluate the overall performance. A detailed economic analysis is performed together with a sensitivity analysis based on variations in the rate of return due to varying biomass price, total capital investment, and natural gas prices. The quantitive results showed considerable SNG production but significantly reduced electricity production. There is a substantial CO2 abatement potential combining CO2 capture and CO2 mitigation from SNG use replacing compressed natural gas (CNG) or gasoline. The economic performance through sensitivity analysis reflects significant dependency on both substitute natural gas production and natural gas market price. Furthermore, the solutions to address the challenges and barriers for the successful commercial implementation of BLG based polygeneration system at small NPMs are discussed. The system performance and discussion on the real application of integrated system presented in this article form a vital literature source for future use by large number of small non-wood pulp industries.
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| 14. |
- Naqvi, Muhammad Raza, 1983-, et al.
(author)
-
Off-grid electricity generation using mixed biomass compost: : A scenario-based study with sensitivity analysis
- 2017
-
In: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 201, s. 363-370
-
Journal article (peer-reviewed)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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| 15. |
- Naqvi, Salman Raza, et al.
(author)
-
Agro-industrial residue gasification feasibility in captive power plants : A South-Asian case study
- 2021
-
In: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 214
-
Journal article (peer-reviewed)abstract
- The objective of this study is to build knowledge on the potential of agro-industrial residue gasification (AIRG) for use in captive power generation through a comprehensive case study. In order to evaluate the economic viability, key performance indicators, such as net present value (NPV), levelized cost of electricity (LCOE), and operating costs etc. are studied. The major textile industry located in the Raiwind area of Punjab province of Pakistan has been selected. The effect and variations of the capacity factor has also been studied coupled with the levelized cost of electricity. The agricultural residue as feedstock to the gasifier is rice husk that is the abundantly available in South Asia. Furthermore, the impact of government subsidies on natural gas is also under the scope of the study. The agro-industrial residue gasification system is found to be a potential alternative to furnace oil (FO) or gas-based captive power plants (CPPs). The results of residue-based gasification system imply a large potential when comparing the cost of electricity with national grid electricity during the peak hours. Therefore, the proposed gasification system offers economic incentives when the textile industry potentially utilizes gasification-based electricity during peak hours and national grid electricity during off-peak hours. (C) 2020 Elsevier Ltd. All rights reserved.
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| 16. |
- Naqvi, Salman Raza, et al.
(author)
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Catalytic fast pyrolysis of rice husk : Influence of commercial and synthesized microporous zeolites on deoxygenation of biomass pyrolysis vapors
- 2018
-
In: International Journal of Energy Research. - : Wiley-Blackwell. - 0363-907X .- 1099-114X. ; 42:3, s. 1352-1362
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Journal article (peer-reviewed)abstract
- Research on utilization of abundant rice residue for valuable bioenergy products is still not explored completely. A simple, robust, cheap, and one-step fast pyrolysis reactor is still a key demand for production of bioenergy products, ie, high quality bio-oil and biochar. Bio-oil extracted from fast pyrolysis does not have adequate quality (eg, acidic and highly oxygenated). Catalytic fast pyrolysis using zeolites in the fast pyrolysis process effectively reduces the oxygen content (no H-2 required). In this paper, the zeolites with different pore sizes and shapes (small pore, SAPO-34 (0.56) and ferrierite (30); medium pore, ZSM-5 (30), MCM-22 (30), and ITQ-2 (30); and large pore zeolite, mordenite (30)) were tested in a drop-type fixed-bed pyrolyzer. Catalytic deoxygenation is conducted at 450 degrees C at the catalyst/biomass ratio of 0.1. Zeolite catalysts, its pore size and shape, could influence largely on deoxygenation. It was found that the small pore zeolites did not produce aromatics as compared to higher amount of aromatics formed in case of medium pore zeolites. ZSM-5 and ITQ-2 zeolites were especially efficient for the higher deoxygenation of biomass pyrolysis vapors due to better pore dimension and higher acidity.
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| 17. |
- Naqvi, Salman Raza, et al.
(author)
-
Catalytic Pyrolysis Of Botryococcus Braunii (microalgae) Over Layered and Delaminated Zeolites For Aromatic Hydrocarbon Production
- 2017
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In: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY. - : ELSEVIER SCIENCE BV. ; , s. 381-385
-
Conference paper (peer-reviewed)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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| 18. |
- Naqvi, Salman Raza, et al.
(author)
-
Circular Economy Approach to Address the Industrial Solid Waste Management
- 2022
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In: Handbook of Solid Waste Management. - Singapore : Springer. - 9789811642296 - 9789811642302 ; , s. 421-440
-
Book chapter (other academic/artistic)abstract
- Industrial activities continuously generate diverse characteristics of various types of wastes. Industrial wastes varied from various process residues, wastes from pollution, or decontamination from operations and materials resulting from activities for contaminated soil remediation, ashes, oil, acidic wastes, plastic, paper, wood, fiber, rubber, metals, and glass. The circular tools indicate a restorative and regenerative system in which the streams of materials and products take place in a circular way. Considering social pressures, major industrial enterprises perceived the need for readjusting their production chains according to circular chains, which are more sustainable and consider the generated waste. This study aims to present the factors for sustainable waste management in major industrial enterprises based on the circular economy approach. The available data of a waste company is considered, and the model of circular economy such as fault tree analysis is applied to figure out the implementation of a circular process to industrial waste, especially those of lower value that have greater difficulties in being processed. The last section will propose a framework, opportunities, challenges, and trade-offs promoting circulatory industrial waste management.
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| 19. |
- Naqvi, Salman Raza, et al.
(author)
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Impact of layered and delaminated zeolites on catalytic fast pyrolysis of microalgae using fixed-bed reactor and Py-GC/MS
- 2021
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In: Journal of Analytical and Applied Pyrolysis. - : Elsevier. - 0165-2370 .- 1873-250X. ; 155
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Journal article (peer-reviewed)abstract
- The aim of this work is to exploit the pyrolysis characteristics of microalgae Botryococcus braunii (BB) with a medium pore framework zeolite (MCM-22) and its delaminated counterpart with a higher external surface area zeolite (ITQ-2) using pyrolysis-gas-chromatography-mass-spectrometry (Py-GC/MS) and a fixed-bed reactor. The study evaluates the effect of synthesized zeolites that possess different pore size, shape and acidity on promoting deoxygenation reactions and producing aromatic compounds during the pyrolysis of microalgae. Further, the role of the shape of zeolites (layered & delaminated) for carbohydrate, protein and lipid-derived compounds formation is discussed. The Py-GC/MS results showed that the aromatic compounds (area%) was significantly higher (35.17 %) for delaminated & (28.76 %) for layered zeolites than non-catalytic pyrolysis (17.85 %) at the catalyst/biomass ratio of 10.1. The increase in catalyst/biomass ratio from 3 to 10 at 550 °C has increased the aromatics (90.66 % for ITQ-2 & 75.25 %) for MCM-22 zeolites. In addition, ITQ-2 zeolite produced 20.47 % higher aromatics than MCM-22 zeolites which is attributed to the thinner delaminated structure of ITQ-2 that makes reactants more accessible to the catalytic site and accelerate the deoxygenation reactions.
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| 20. |
- Naqvi, Salman Raza, et al.
(author)
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New trends in improving gasoline quality and octane through naphtha isomerization : a short review
- 2018
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In: APPLIED PETROCHEMICAL RESEARCH. - : Springer. - 2190-5533 .- 2190-5533 .- 2190-5525. ; 8:3, s. 131-139
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Research review (peer-reviewed)abstract
- The octane enhancement of light straight run naphtha is one of the significant solid acid catalyzed processes in the modern oil refineries due to limitations of benzene, aromatics, and olefin content in gasoline. This paper aims to examine the role of various catalysts that are being utilized for the isomerization of light naphtha with an ambition to give an insight into the reaction mechanism at the active catalyst sites, and the effect of various contaminants on catalyst activity. In addition, different technologies used for isomerization process are evaluated and compared by different process parameters.
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| 21. |
- Naqvi, Salman Raza, et al.
(author)
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Potential of biomass for bioenergy in Pakistan based on present case and future perspectives
- 2018
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In: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 81:1, s. 1247-1258
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Research review (peer-reviewed)abstract
- Future energy security and environmental issues are major driving forces for increased biomass utilization globally and especially in developing countries like Pakistan. For efficient utilization of indigenous biomass resources in the future energy mix, it is important to gain knowledge of current energy system in various sectors. Some of the technologies and initiatives are under development to achieve transition from non-renewable resources to renewable resources, and reducing fossil fuel dependency and greenhouse gas emissions. Recently, number of proposals has been presented for the development of sustainable biofuels production methods for promise for accelerating a shift away from an unsustainable approach to possible sustainable production practices or a sustainable social, economic and environment. This article presents an extensive literature review of the biomass-based renewable energy potential in Pakistan based on current energy scenario and future perspectives. It also highlights the availability of the indigenous and local biomass resources and potential biomass conversion technologies to convert such resources to bioenergy. The drivers for utilization of indigenous biomass resources in future energy mix and challenges regarding awareness among stakeholders and R & D to fill knowledge gaps are economically restraints. The article concludes with suggestions on future directions and policies for effective implementation of biomass based renewable energy production.
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| 22. |
- Naqvi, Salman Raza, et al.
(author)
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Pyrolysis of high ash sewage sludge : Kinetics and thermodynamic analysis using Coats-Redfern method
- 2019
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In: Renewable energy. - : Elsevier Ltd. - 0960-1481 .- 1879-0682. ; 131, s. 854-860
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Journal article (peer-reviewed)abstract
- This study aims to investigate the thermo-kinetics of high-ash sewage sludge using thermogravimetric analysis. Sewage sludge was dried, pulverized and heated non-isothermally from 25 to 800 °C at different heating rates (5, 10 and 20 °C/min) in N2 atmosphere. TG and DTG results indicate that the sewage sludge pyrolysis may be divided into three stages. Coats-Redfern integral method was applied in the 2nd and 3rd stage to estimate the activation energy and pre-exponential factor from mass loss data using five major reaction mechanisms. The low-temperature stable components (LTSC) of the sewage sludge degraded in the temperature regime of 250–450 °C while high-temperature stable components (HTSC) decomposed in the temperature range of 450–700 °C. According to the results, first-order reaction model (F1) showed higher Ea with better R2 for all heating rates. D3, N1, and S1 produced higher Ea at higher heating rates for LTSC pyrolysis and lower Ea with the increase of heating rates for HTSC pyrolysis. All models showed positive ΔH except F1.5. Among all models, Diffusion (D1, D2, D3) and phase interfacial models (S1, S2) showed higher ΔG as compared to reaction, nucleation, and power-law models in section I and section II.
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| 23. |
- Naqvi, Salman Raza, et al.
(author)
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Pyrolysis of high-ash sewage sludge : Thermo-kinetic study using TGA and artificial neural networks
- 2018
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In: Fuel. - Oxon, UK : Elsevier Ltd. - 0016-2361 .- 1873-7153. ; 233, s. 529-538
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Journal article (peer-reviewed)abstract
- Pyrolysis of high-ash sewage sludge (HASS) is a considered as an effective method and a promising way for energy production from solid waste of wastewater treatment facilities. The main purpose of this work is to build knowledge on pyrolysis mechanisms, kinetics, thermos-gravimetric analysis of high-ash (44.6%) sewage sludge using model-free methods & results validation with artificial neural network (ANN). TG-DTG curves at 5,10 and 20 °C/min showed the pyrolysis zone was divided into three zone. In kinetics, E values of models ranges are; Friedman (10.6–306.2 kJ/mol), FWO (45.6–231.7 kJ/mol), KAS (41.4–232.1 kJ/mol) and Popescu (44.1–241.1 kJ/mol) respectively. ΔH and ΔG values predicted by OFW, KAS and Popescu method are in good agreement and ranged from (41–236 kJ/mol) and 53–304 kJ/mol, respectively. Negative value of ΔS showed the non-spontaneity of the process. An artificial neural network (ANN) model of 2 * 5 * 1 architecture was employed to predict the thermal decomposition of high-ash sewage sludge, showed a good agreement between the experimental values and predicted values (R2 ⩾ 0.999) are much closer to 1. Overall, the study reflected the significance of ANN model that could be used as an effective fit model to the thermogravimetric experimental data. © 2018 Elsevier Ltd
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| 24. |
- Naqvi, Salman Raza, et al.
(author)
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Recent developments on sewage sludge pyrolysis and its kinetics : Resources recovery, thermogravimetric platforms, and innovative prospects
- 2021
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In: Computers and Chemical Engineering. - : Elsevier. - 0098-1354 .- 1873-4375. ; 150
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Journal article (peer-reviewed)abstract
- Sewage sludge is a by-product of the wastewater treatment process, which has the potential to be a source of transport fuels, heat, and power using the pyrolysis process. Considering the prevalence and disposal issues associated with sewage sludge, the objective of this study is to critically review the recent advancements in sewage sludge pyrolysis and its kinetics obtained using the thermogravimetric techniques, and other associated different kinetic models documented in the literature. The study will identify optimum operating conditions and design parameters to obtain high yields. The state-of-the-art perspectives and the challenges associated with full-scale implementation are highlighted for biofuels and resource recovery from the sewage sludge. Furthermore, machine-learning approaches in thermal kinetics of pyrolysis are presented and discussed in terms of their effectiveness in predicting thermal kinetics data. Finally, the challenges for a successful implementation and commercial viability of sewage sludge pyrolysis are discussed.
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| 25. |
- Naqvi, Salman Raza, et al.
(author)
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The role of zeolite structure and acidity in catalytic deoxygenation of biomass pyrolysis vapors
- 2015
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In: CLEAN, EFFICIENT AND AFFORDABLE ENERGY FOR A SUSTAINABLE FUTURE. - : Elsevier. ; 75, s. 793-800
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Conference paper (peer-reviewed)abstract
- Catalytic upgrading of paddy husk was performed over 10-MR zeolites (MCM-22, ITQ-2 and ZSM-5) in a drop type fixed-bed reactor. This work investigated the role of structure and acidity of zeolites on pyrolysis-oil yield and degree of deoxygenation. Catalytic pyrolysis experiments were carried out at the catalyst/biomass ratio (0.05 -0.5) at temperature of 450 degrees C. The oil yield decreased by using catalyst and this decrease oil yield is attributed to catalytic cracking of bio-oil vapor on the catalyst. The route for deoxygenation of pyrolysis vapors was identified to be dehydration, decarboxylation and decarboxylation. ITQ-2 showed high degree of deoxygenation as compare to MCM-22 which is due to more accessible external active sites of ITQ-2. The organics yield in pyrolysis oil was highest with ZSM-5 in comparison with other zeolites. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
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