| 1. |
- Munir, M. Adeel, et al.
(författare)
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Blockchain Adoption for Sustainable Supply Chain Management : Economic, Environmental, and Social Perspectives
- 2022
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Ingår i: Frontiers in Energy Research. - : Frontiers Media S.A.. - 2296-598X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Due to the rapid increase in environmental degradation and depletion of natural resources, the focus of researchers is shifted from economic to socio-environmental problems. Blockchain is a disruptive technology that has the potential to restructure the entire supply chain for sustainable practices. Blockchain is a distributed ledger that provides a digital database for recording all the transactions of the supply chain. The main purpose of this research is to explore the literature relevant to blockchain for sustainable supply chain management. The focus of this review is on the sustainability of the blockchain-based supply chain concerning environmental conservation, social equality, and governance effectiveness. Using a systematic literature review, a total of 136 articles were evaluated and categorized according to the triple bottom-line aspects of sustainability. Challenges and barriers during blockchain adoption in different industrial sectors such as aviation, shipping, agriculture and food, manufacturing, automotive, pharmaceutical, and textile industries were critically examined. This study has not only explored the economic, environmental, and social impacts of blockchain but also highlighted the emerging trends in a circular supply chain with current developments of advanced technologies along with their critical success factors. Furthermore, research areas and gaps in the existing research are discussed, and future research directions are suggested. The findings of this study show that blockchain has the potential to revolutionize the entire supply chain from a sustainability perspective. Blockchain will not only improve the economic sustainability of the supply chain through effective traceability, enhanced visibility through information sharing, transparency in processes, and decentralization of the entire structure but also will help in achieving environmental and social sustainability through resource efficiency, accountability, smart contracts, trust development, and fraud prevention. The study will be helpful for managers and practitioners to understand the procedure of blockchain adoption and to increase the probability of its successful implementation to develop a sustainable supply chain network.
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| 2. |
- Ashraf, Waqar Muhammad, et al.
(författare)
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Artificial intelligence based operational strategy development and implementation for vibration reduction of a supercritical steam turbine shaft bearing
- 2022
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Ingår i: Alexandria Engineering Journal. - 1110-0168 .- 2090-2670. ; 61:3, s. 1864-1880
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Tidskriftsartikel (refereegranskat)abstract
- The vibrations of bearings holding the high-speed shaft of a steam turbine are critically controlled for the safe and reliable power generation at the power plants. In this paper, two artificial intelligence (AI) process models, i.e., artificial neural network (ANN) and support vector machine (SVM) based relative vibration modeling of a steam turbine shaft bearing of a 660 MW supercritical steam turbine system is presented. After extensive data processing and machine learning based visualization tests performed on the raw operational data, ANN and SVM models are trained, validated and compared by external validation tests. ANN has outperformed SVM in terms of better prediction capability and is, therefore, deployed for simulating the constructed operating scenarios. ANN process model is tested for the complete load range of power plant, i.e., from 353 MW to 662 MW and 4.07% reduction in the relative vibration of the bearing is predicted by the network. Further, various vibration reduction operating strategies are developed and tested on the validated and robust ANN process model. A selected operating strategy which has predicted a promising reduction in the relative vibration of bearing is selected. In order to confirm the effectiveness of the prediction of the ANN process model, the selected operating strategy is implemented on the actual operation of the power plant. The resulting reduction in the relative vibrations of the turbine's bearing, which is less than the alarm limit, are confirmed. This cements the role of ANN process model to be used as an operational excellence tool resulting in vibration reduction of high-speed rotating equipment. (c) 2021 THE AUTHORS. Production and hosting by Elsevier B.V. on behalf of Faculty of Engineering, Alexandria University This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 3. |
- Khan, Muhammad Ahsan Iqbal, et al.
(författare)
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An Experimental and Comparative Performance Evaluation of a Hybrid Photovoltaic-Thermoelectric System
- 2021
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Ingår i: Frontiers in Energy Research. - : FRONTIERS MEDIA SA. - 2296-598X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The majority of incident solar irradiance causes thermalization in photovoltaic (PV) cells, attenuating their efficiency. In order to use solar energy on a large scale and reduce carbon emissions, their efficiency must be enhanced. Effective thermal management can be utilized to generate additional electrical power while simultaneously improving photovoltaic efficiency. In this work, an experimental model of a hybrid photovoltaic-thermoelectric generation (PV-TEG) system is developed. Ten bismuth telluride-based thermoelectric modules are attached to the rear side of a 10 W polycrystalline silicon-based photovoltaic module in order to recover and transform waste thermal energy to usable electrical energy, ultimately cooling the PV cells. The experiment was then carried out for 10 days in Lahore, Pakistan, on both a simple PV module and a hybrid PV-TEG system. The findings revealed that a hybrid system has boosted PV module output power and conversion efficiency. The operating temperature of the PV module in the hybrid system is reduced by 5.5%, from 55 degrees C to 52 degrees C. Due to a drop in temperature and the addition of some recovered energy by thermoelectric modules, the total output power and conversion efficiency of the system increased. The hybrid system's cumulative output power increased by 19% from 8.78 to 10.84 W, compared to the simple PV system. Also, the efficiency of the hybrid PV-TEG system increased from 11.6 to 14%, which is an increase of 17% overall. The results of this research could provide consideration for designing commercial hybrid PV-TEG systems.
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| 4. |
- Masrur Hossain, M., et al.
(författare)
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Analysis and optimization of a modified Kalina cycle system for low-grade heat utilization
- 2021
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Ingår i: Energy Conversion and Management. - : Elsevier Ltd. - 2590-1745. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Kalina cycle system (KCS) offers an attractive prospect to produce power by utilizing low-grade heat sources where traditional power cycles cannot be implemented. Intending to explore the potential of exploiting low-grade heat sources for conversion to electrical energy, this study proposes two modified power generation cycles based on KCS-34. A multi-phase expander is positioned between the Kalina separator and the second heat regenerator in the proposed X-modification. In contrast, it is located between the mixer and second regenerator for Y-modification. To explore the potential benefits and limitations of the proposed modifications contrasted with the KCS-34, thermodynamic modeling and optimization have been conducted. The influence of critical decision parameters on overall cycle performance is analyzed. The result elucidates that by implementing an additional multi-phase expander, a significant amount of energy can be extracted from a lean ammonia water loop and X-modification can deliver superior thermodynamic performance compared with the Y-modification and the original KCS-34. With a reduced turbine inlet pressure of 58 bar and an ammonia concentration of 80%, the X-modified cycle's efficiency reaches a peak value of 17% and a net power yield of 1015 kW. An increase of 6.35% can be achieved compared with the conventional KCS-34 operating at the same conditions. Maximum exergy destruction of the working substance was observed in the condenser.
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| 5. |
- Naqvi, Muhammad, et al.
(författare)
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Polygeneration system integrated with small non-wood pulp mills for substitute natural gas production
- 2018
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 224, s. 636-646
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Queiroz, Marcus Vinicius Almeida, et al.
(författare)
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Experimental comparison between R134a/R744 and R438A/R744 (drop-in) cascade refrigeration systems based on energy consumption and greenhouse gases emissions
- 2021
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Ingår i: Energy Science & Engineering. - : Wiley. - 2050-0505. ; 9:12, s. 2281-2297
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Tidskriftsartikel (refereegranskat)abstract
- This experimental study evaluates the energy performance and climatic changes of a cascade cooling system operating with the R134a/R744 pairs (cooling capacity of 4.5-6 kW) and R438A/R744. In both cases, the low-temperature refrigerant, R744, operated under subcritical conditions. The experimental apparatus basically consists of two vapor-compression cycles coupled by a plate cascade condenser. Two operational variables, from R744 cycle, were controlled: the degree-of-superheat and the compressor frequency. The experiment was initially assembled to pair R134a/R744. Subsequently, the R134a refrigerant charge in the high-temperature cycle was replaced by R438A, on a drop-in basis. The two systems, R134a/R744 and R438A/R744, were compared for similar cooling capacities and cold chamber air temperatures. Results showed that the energy consumption of the high-temperature compressor, operating with R438A, was higher than R134a for all tests. As a result, the COP values for R438A/R744 were 30% lower than those for R134a/R744. The greenhouse gases emissions of the two systems were evaluated using the total equivalent warming impact factor, TEWI, whose value for the R438A/R744 pair was approximately 29.5% higher, compared with R134a/R744. Since R438A was originally designed to substitute R22, a few comparative tests were carried out with the latter, always with R744 as the low-temperature cycle working fluid.
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| 7. |
- Raihan Uddin, M., et al.
(författare)
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Energy analysis of a solar driven vaccine refrigerator using environment-friendly refrigerants for off-grid locations
- 2021
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Ingår i: Energy Conversion and Management. - : Elsevier Ltd. - 2590-1745. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- In many remote localities, one of the underlying reasons for not receiving life-saving vaccines is the lack of electricity to store the vaccines in the required refrigerated conditions. Solar Photovoltaic (PV) refrigerators have been considered as a viable and green solution to store the vaccines in remote localities having no access to electricity. In this paper, a detailed methodology has been presented for the performance evaluation of a solar PV powered vaccine refrigerator for remote locations. Thermal modelling with hourly cooling load calculations and refrigeration cycle simulations were carried out. The performance parameters for three environment-friendly refrigerants: R152a, R1234yf, and R1234ze(E) has been compared against the commonly used R134a for two remote, off-grid locations in Bangladesh and South Sudan. The energy systems comprising of solar PV panels and batteries to run the refrigerator were modelled in HOMER software for techno-economic optimizations. For both the locations, R152a was found to be the best performing refrigerant exhibiting higher COP (2%−5.29%) as compared to the other refrigerants throughout the year, while R1234ze(E) exhibited COPs on par with R134a, and R1234yf had the least performance. Techno-economic analysis showed an energy system providing electricity to the refrigerator with R152a also had lower levelized cost of electricity (0.48%−2.54%) than the systems having other refrigerants in these locations.
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| 8. |
- Saif-Ul-Allah, Muhammad Waqas, et al.
(författare)
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Computationally Inexpensive 1D-CNN for the Prediction of Noisy Data of NOx Emissions From 500 MW Coal-Fired Power Plant
- 2022
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Ingår i: Frontiers in Energy Research. - : FRONTIERS MEDIA SA. - 2296-598X. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Coal-fired power plants have been used to meet the energy requirements in countries where coal reserves are abundant and are the key source of NOx emissions. Owing to the serious environmental and health concerns associated with NOx emissions, much work has been carried out to reduce NOx emissions. Sophisticated artificial intelligence (AI) techniques have been employed during the past few decades, such as least-squares support vector machine (LSSVM), artificial neural networks (ANN), long short-term memory (LSTM), and gated recurrent unit (GRU), to develop the NOx prediction model. Several studies have investigated deep neural networks (DNN) models for accurate NOx emission prediction. However, there is a need to investigate a DNN-based NOx prediction model that is accurate and computationally inexpensive. Recently, a new AI technique, convolutional neural network (CNN), has been introduced and proven superior for image class prediction accuracy. According to the best of the author's knowledge, not much work has been done on the utilization of CNN on NOx emissions from coal-fired power plants. Therefore, this study investigated the prediction performance and computational time of one-dimensional CNN (1D-CNN) on NOx emissions data from a 500 MW coal-fired power plant. The variations of hyperparameters of LSTM, GRU, and 1D-CNN were investigated, and the performance metrics such as RMSE and computational time were recorded to obtain optimal hyperparameters. The obtained optimal values of hyperparameters of LSTM, GRU, and 1D-CNN were then employed for models' development, and consequently, the models were tested on test data. The 1D-CNN NOx emission model improved the training efficiency in terms of RMSE by 70.6% and 60.1% compared to LSTM and GRU, respectively. Furthermore, the testing efficiency for 1D-CNN improved by 10.2% and 15.7% compared to LSTM and GRU, respectively. Moreover, 1D-CNN (26 s) reduced the training time by 83.8% and 50% compared to LSTM (160 s) and GRU (52 s), respectively. Results reveal that 1D-CNN is more accurate, more stable, and computationally inexpensive compared to LSTM and GRU on NOx emission data from the 500 MW power plant.
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| 9. |
- Saif-ul-Allah, M. W., et al.
(författare)
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Gated Recurrent Unit Coupled with Projection to Model Plane Imputation for the PM2.5 Prediction for Guangzhou City, China
- 2022
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Ingår i: Frontiers in Environmental Science. - : Frontiers Media S.A.. - 2296-665X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Air pollution is generating serious health issues as well as threats to our natural ecosystem. Accurate prediction of PM2.5 can help taking preventive measures for reducing air pollution. The periodic pattern of PM2.5 can be modeled with recurrent neural networks to predict air quality. To the best of the author’s knowledge, very limited work has been conducted on the coupling of missing value imputation methods with gated recurrent unit (GRU) for the prediction of PM2.5 concentration of Guangzhou City, China. This paper proposes the combination of project to model plane (PMP) with GRU for the superior prediction performance of PM2.5 concentration of Guangzhou City, China. Initially, outperforming the missing value imputation method PMP is proposed for air quality data under consideration by making a comparison study on various methods such as KDR, TSR, IA, NIPALS, DA, and PMP. Secondly, it presents GRU in combination with PMP to show its superiority on other machine learning techniques such as LSSVM and two other RNN variants, LSTM and Bi-LSTM. For this study, data for Guangzhou City were collected from China’s governmental air quality website. Data contained daily values of PM2.5, PM10, O3, SOx, NOx, and CO. This study has employed RMSE, MAPE, and MEDAE as model prediction performance criteria. Comparison of prediction performance criteria on the test data showed GRU in combination with PMP has outperformed the LSSVM and other RNN variants LSTM and Bi-LSTM for Guangzhou City, China. In comparison with prediction performance of LSSVM, GRU improved the prediction performance on test data by 40.9% RMSE, 48.5% MAPE, and 50.4% MEDAE.
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| 10. |
- 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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| 11. |
- Salman, Chaudhary Awais, 1986-, et al.
(författare)
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Future directions for CHP plants using biomass and waste - Adding production of vehicle fuels
- 2019
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Ingår i: E3S Web of Conferences. - : EDP Sciences. - 2267-1242.
-
Konferensbidrag (refereegranskat)abstract
- In Northern Europe, the production of many biobased CHP plants is getting affected due to the enormous expansion of wind and solar power. In addition, heat demand varies throughout the year, and existing CHP plants show less technical performance and suffer economically. By integrating the existing CHP plants with other processes for the production of chemicals, they can be operated more hours, provide operational and production flexibility and thus increase efficiency and profitability. In this paper, we look at a possible solution by converting an existing CHP plant into integrated biorefinery by retrofitting pyrolysis and gasification process. Pyrolysis is retrofitted in an existed CHP plant. Bio-oil obtained from pyrolysis is upgraded to vehicle grade biofuels. Gasification process located upfront of CHP plant provides the hydrogen required for upgradation of biofuel. The results show that a pyrolysis plant with 18 ton/h feed handling capacity (90 MWth), when integrated with gasification for hydrogen requirement and CHP plant for heat can produce 5.2 ton/h of gasoline/diesel grade biofuels. The system integration gives positive economic benefits too but the annual operating hours can impact economic performance.
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| 12. |
- Salman, Chaudhary Awais, 1986-, et al.
(författare)
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Gasification process integration with existing combined heat and power plants for polygeneration of dimethyl ether or methanol : A detailed profitability analysis
- 2018
-
Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 226, s. 116-128
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Tidskriftsartikel (refereegranskat)abstract
- Combustion of waste for cogeneration of heat and power is the most convenient and practical choice to carry out through combined heat and power (CHP) plants. But, seasonal variation in heat demand throughout the year affects the operation of CHP plants. This fluctuation in the CHP operation cause less annual operating hours for the plant equipment and is also not profitable for stakeholders. This study aims to assess the technical potential of integrated gasification process with existing CHP plants for either dimethyl ether (DME) or methanol production through refuse-derived fuel (RDF). Process integration considers that the CHP plant provides the necessary heat for biofuel synthesis during off-peak hours. Mass and heat integration methods are used to develop and simulate the polygeneration processes for heat, power, and biofuel production. Both technical and economic indicators are reported and compared to assess the potential for both biofuels through process integration. Annual operation data of a real CHP plant has been extracted to evaluate the integrated processes. A flexible gasification configuration is selected for the integrated approach i.e. CHP runs at full load to provide the heat demand and only the excess heat of CHP plant is utilized for biofuel production. The energetic efficiencies of the polygeneration systems are compared with the standalone systems. Technical analysis of process integration shows the enhancement of the operational capacity of CHP during off-peak hours and it can produce biofuels without compromising the annual heat demand. Production of methanol through process integration shows ∼67% energetic efficiency while methanol production gives ∼65%. The efficiencies are higher than standalone DME and methanol processes (51% and 53%, respectively) but lower than standalone CHP plant i.e. 81%, however the process integration increases the operating time of the CHP plant with more economic benefits. Economic analysis coupled with uncertainty analysis through Monte Carlo simulations shows that by integrating CHP with gasifier to produce biofuels is significantly profitable as compared with only heat and electricity production. But, DME as a potential product shows more economic benefits than methanol. The uncertainty analysis through Monte Carlo simulations shows that the profitable probability of DME as a product in future is also greater than methanol due to higher DME selling price. The uncertainty analysis further shows that prices of DME and methanol with waste biomass prices in future will have a greater impact on the economic performance of the proposed polygeneration process.
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| 13. |
- Salman, Chaudhary Awais, 1986-, et al.
(författare)
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Identification of thermochemical pathways for the energy and nutrient recovery from digested sludge in wastewater treatment plants
- 2019
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Ingår i: Energy Procedia. - : Elsevier Ltd. - 1876-6102. ; , s. 1317-1322, s. 1317-1322
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Konferensbidrag (refereegranskat)abstract
- There are several restrictions and limitations on the emissions and disposal of materials and pollutants related to wastewater treatment plants (WWTPs) emphasizing improvement of current processes and development of new methods. Process integration is one way to use all fractions of waste for improved efficiency. WWTPs produces sludge which is usually anaerobically digested to produce biogas and a byproduct called digestate. Digestate is an organic material that contains macro and micronutrients such as nitrogen, phosphorous, and potassium and also contains heavy metals. Digestate is mainly used for agricultural applications because of the presence of nutrients. However, digestate also contains energy in the form of carbon and hydrogen which can be harnessed through various processes and integrated with nitrogen recovery process. This study aims to recover the energy and nutrients from digestate through thermochemical treatment processes. Combustion, pyrolysis, and gasification are assessed and compared in this work. An ammonia stripping method is assumed to recover nitrogen from digestate. The thermochemical processes are heat integrated with ammonia stripping through modeling and simulation. Results show that almost half of the energy present in digested sludge is required for its drying. Moreover, nitrogen recovery also requires much energy. The combustion and gasification of digested sludge give better results than pyrolysis. The heat integration becomes feasible when the auxiliary biogas is also burned along with products from the thermochemical treatment of sludge.
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| 14. |
- Salman, Chaudhary Awais, 1986-
(författare)
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Integration of thermochemical processes with existing waste management industries to enhance biomethane production
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In most waste management industries, waste is separated into different fractions, each of which is treated with suitable processes. Established technologies such as waste combustion for combined heat and power (CHP) production and biomethane production through anaerobic digestion (AD) of biodegradable waste work fine as standalone processes. However, specific issues are associated with these established standalone waste-to-energy (WtE) processes. For example, traditional CHP plants have high overall energy efficiencies, but lower electrical efficiencies, and their heat outputs are dependent on local demand and seasonal variations. Similarly, biodegradable waste typically sent for AD contains lignocellulosic or green waste. Due to the lower biodegradability of lignocellulosic waste, only a proportion is sent for digestion, while the rest is incinerated, increasing transportation costs. Increased benefits from the perspective of energy and economics can be achieved by integrating new WtE processes with existing technologies. This thesis aims to design energy-efficient and profitable biorefineries by integrating existing waste management facilities with the thermochemical treatment of waste. A systems analysis of two process integration concepts has been studied through modelling and simulation. The first analysis is of the process integration of gasification with existing CHP plants, and the second is the process integration of pyrolysis with an existing AD plant. For integration of gasification with a CHP plant, reasonable operational limits of the CHP plant have been assessed and compared by integrating three types of gasifier, and the most technically and economically integrated processes have been identified. In the case of integration of pyrolysis with AD, a new process configuration is presented that couples the AD of biodegradable waste with the pyrolysis of lignocellulosic waste. The biochar obtained from pyrolysis is added to a digester as an adsorbent to increase the biomethane production. In addition, the vapors produced by the pyrolysis process are converted to biomethane. Two different conversion processes are compared to convert pyrolysis vapors to biomethane, catalytic methanation and biomethanation. The results demonstrate that process integration can contribute to reducing the cost of biomethane production through integration of gasification and pyrolysis with CHP and AD, respectively. The process integration can also utilize infrastructure and products from existing industries and increase the overall process efficiencies. Of the gasifiers studied, the dual fluidized bed gasifier produces more biomethane than the circulating bed and entrained flow gasifiers when retrofitted with an existing CHP plant with up to 85% efficiency. The CHP–gasification integration is capable of producing more biomethane during low heat demand seasons without disturbing the operation of the CHP operation. A gasifier with a flexible capacity can be integrated with the CHP to produce biomethane without affecting the heat production of the CHP. From an economic perspective, the dual-bed gasifier requires lower capital investment and is therefore more profitable, because it requires less equipment than the circulating fluidized and entrained flow gasifiers. The integration of pyrolysis with the AD process can almost double biomethane production comparison with standalone AD process, increasing efficiency to 67%. The integration is an attractive investment when catalytic methanation of syngas is used rather than biomethanation of syngas. The catalytic methanation route has an economic rate of return of 16%, with a six-year payback period. The main conclusion drawn from this thesis is that production of biomethane can be enhanced through process integration of gasification with the CHP plant and of pyrolysis with AD. However, the increase in biomethane production also increases the demand for waste at the integrated biorefinery. Hence, the capacity of the gasifier and pyrolysis process will be decisive in determining the level of integration of the biorefineries.
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| 15. |
- Salman, Chaudhary Awais, 1986-, et al.
(författare)
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Opportunities and limitations for existing CHP plants to integrate polygeneration of drop-in biofuels with onsite hydrogen production
- 2020
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Ingår i: Energy Conversion and Management. - : Elsevier Ltd. - 0196-8904 .- 1879-2227. ; 221
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Tidskriftsartikel (refereegranskat)abstract
- Over the past few years, there has been increasing research interest in retrofitting existing combined heat and power (CHP) plants with new technologies to co-produce other products. The focus has been on the design of fixed-sized processes for integration into CHP plants without affecting their performance. The primary objective of this study was to test the limits of a CHP plant with respect to retrofitting flexible thermochemical conversion of waste to drop-in biofuels with properties similar to petroleum fuels. Waste conversion to drop-in biofuels also requires significant amount of hydrogen for drop-in biofuels synthesis — Required hydrogen was also produced onsite in thermochemical processes integrated with CHP plant. The secondary objective was to determine the maximum number of days a flexible retrofitted waste-thermochemical process can run annually using only excess heat from a CHP plant, and whether such processes are profitable when operating flexibly. The results show that the selection of heat extraction points for the utilization of excess heat from the CHP plant for energy-intensive processes is critical for maintaining the flexibility of the integrated thermochemical processes. Thermochemical processes integrated with CHP plants were able to operate on approximately 180 days of the year by utilizing only excess heat from the CHP plant. Integration of pyrolysis showed more flexibility than integration of gasification. Onsite hydrogen production was the main limiting factor for the integration of thermochemical process with the existing CHP plant to produce drop-in biofuels. Hydrogen produced with a solid oxide electrolysis cell (SOEC) decreased the overall system efficiency and limited the capacity of the overall process. However, hydrogen production from a water gas shift (WGS) reactor was more expensive. The results also indicated that small changes in the financial parameters have a large impact on the economic performance of the integrated process.
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| 16. |
- Salman, Chaudhary Awais, 1986-, et al.
(författare)
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Process Modelling and Simulation of Waste Gasification-Based Flexible Polygeneration Facilities for Power, Heat and Biofuels Production
- 2020
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 13:16
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Tidskriftsartikel (refereegranskat)abstract
- There is increasing interest in the harnessing of energy from waste owing to the increase in global waste generation and inadequate currently implemented waste disposal practices, such as composting, landfilling or dumping. The purpose of this study is to provide a modelling and simulation framework to analyze the technical potential of treating municipal solid waste (MSW) and refuse-derived fuel (RDF) for the polygeneration of biofuels along with district heating (DH) and power. A flexible waste gasification polygeneration facility is proposed in this study. Two types of waste—MSW and RDF—are used as feedstock for the polygeneration process. Three different gasifiers—the entrained flow gasifier (EFG), circulating fluidized bed gasifier (CFBG) and dual fluidized bed gasifier (DFBG)—are compared. The polygeneration process is designed to produce DH, power and biofuels (methane, methanol/dimethyl ether, gasoline or diesel and ammonia). Aspen Plus is used for the modelling and simulation of the polygeneration processes. Four cases with different combinations of DH, power and biofuels are assessed. The EFG shows higher energy efficiency when the polygeneration process provides DH alongside power and biofuels, whereas the DFBG and CFBG show higher efficiency when only power and biofuels are produced. RDF waste shows higher efficiency as feedstock than MSW in polygeneration process.
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| 17. |
- Salman, Chaudhary Awais, 1986-
(författare)
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Production of biodiesel from waste vegetable oil
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In the present project technological and economical aspects of biodiesel was studied, in first part of project bio diesel was synthesized from Waste vegetable Oil (WVO) by three-step method and regressive analyzes of the process was done. The raw oil was collected from local restaurant of Barcelona city in Spain. In the three-step method, the first step is saponification of the oil followed by acidification to produce FFA and finally esterification of FFA to produce biodiesel. In the saponification reaction, various reaction parameters such as oil to sodium hydroxide molar ratio and reaction time were optimized and the oil to NaOH molar ratio was 1:2, In the esterification reaction, the reaction parameters such as methanol to FFA molar ratio, catalyst concentration and reaction temperature were optimized Finally HHV of biodiesel was measured and compared with biodiesel and petro-diesel standard. It was found almost equal to petro diesel produced by National Refinery of Pakistan i.e. 40000 KJ/Kg. In second part detailed market survey was done in restaurants in order to check the supply of raw material and need of the targeted market and then detailed economical analysis was also done in order to check the feasibility of the project in the target market in Pakistan. The market is not saturated and there is a need of the product but initial capital investment found is higher and investors will have to wait for the revenues.
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| 18. |
- Salman, Chaudhary Awais, 1986-, et al.
(författare)
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Synergistic combination of pyrolysis, anaerobic digestion, and CHP plants
- 2019
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Ingår i: Energy Procedia. - : Elsevier. - 1876-6102. ; , s. 1323-1329, s. 1323-1329
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Konferensbidrag (refereegranskat)abstract
- The anaerobic digestion of biodegradable fraction of municipal solid waste (MSW) is a widely used process for biogas production. However, the biodegradable fraction of MSW also contains lignocellulosic waste which hinders the biogas production if added to the digester in higher quantity. So it needs to be separated from biodegradable waste and sent for alternate treatment, e.g., incineration, landfilling or compositing. Pyrolysis of lignocellulosic waste to produce biochar, syngas, and bio oil is an alternate treatment to consider. Furthermore, there is a reported correlation between the addition of biochar in the digester and higher biogas production. Previously, we coupled the pyrolysis of lignocellulosic waste with anaerobic digestion plant. Pyrolysis produces the biochar and vapors. Biochar was added in the digester to enhance the biomethane production. The vapors produced in the pyrolysis process were converted to biomethane through the catalytic methanation process. The combination gives the overall efficiency of 67%. In this work, we modified the process concept to increase the integration level of these processes. The main issue with the pyrolysis process is its heat required to operate, while some of its downstream processes also generate excess heat. In this study, the pyrolysis of lignocellulosic waste is integrated with an operating combined heat and power (CHP) plant, by using its existing infrastructure for heat transport among different pyrolysis operations. The combustor of the CHP plant provides the heat for drying and pyrolysis while the excess heat is transferred back to the combustor. The biochar produced from pyrolysis is transported back to the digester as an adsorbent. The process simulation results show that the combined efficiency of pyrolysis with CHP plant reached 80%. If the biochar is sent back to the anaerobic digester, the synergetic efficiency of all three processes, i.e., pyrolysis-CHP and anaerobic digestion was obtained at 79.7% as compared with the 67% efficiency when the pyrolysis was only integrated with the anaerobic digestion process.
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| 19. |
- Salman, Chaudhary Awais, 1986-, et al.
(författare)
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Uncertainty and influence of input parameters and assumptions on the design and analysis of thermochemical waste conversion processes : A stochastic approach
- 2020
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Ingår i: Energy Conversion and Management. - : Elsevier. - 0196-8904 .- 1879-2227. ; 214
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Tidskriftsartikel (refereegranskat)abstract
- Process design is a challenging task for researchers and engineers. Incomplete information and variation in input data affect the outputs and reliability of key performance indicators (KPIs) of the designed process. The efficient utilization of waste is becoming increasingly important, and researchers use simulation and modelling tools for design and assessment of waste conversion processes. The complex nature of modelling of waste conversion processes and uncertainty of technical and financial data result in substantial variation in the KPIs of the designed process. In this study, we identified the critical parameters and assumptions that cause uncertainty in the process design analysis of waste-to-biofuels conversions. We used a stochastic modelling approach to address these methodological challenges and performed Monte Carlo simulations on waste-to-biofuel processes. The identified uncertain parameters and inputs were varied for a whole year with a one-minute time step. Different thermochemical conversion pathways were modelled by varying uncertain inputs and assumptions over the year by applying Monte Carlo simulations. Variations in the system's technical and economic KPIs were observed and compared. The results show that the heterogeneous nature of waste is a highly sensitive parameter, and a small change in its elemental analysis varies the technical performance significantly. Similarly, operating hours, plant size, capital investment, waste, and biofuel price are also very influential parameters on process design. Furthermore, the feasibility of waste-to-biofuel systems depends largely on how researchers and engineers select these parameters. Overall, the results reveal that by including the uncertainty of input parameters and assumptions in process design, the biases in results could be addressed transparently, making the overall assessment more reliable.
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| 20. |
- Salman, Chaudhary Awais, 1986-
(författare)
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Waste-integrated biorefineries : A path towards efficient utilization of waste
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Waste-management systems have progressed from landfilling and dumping to waste prevention, recycling and resource recovery. In state-of-the-art waste-management industries, waste is separated into various fractions and treated with suitable processes. The non-recyclable organic fraction of waste can be incinerated for combined heat and power (CHP) production, while biodegradable waste can be converted to biomethane through the anaerobic digestion (AD) process. Thermochemical processes such as gasification and pyrolysis provide alternative methods for treating various fractions of waste. This thesis aims to design energy-efficient and cost-effective waste-integrated biorefineries by integrating thermochemical processing of waste with existing WtE technologies.A system analysis of five process-integration case studies have been performed. The first case assesses the limitations and operational limits of thermochemical processes retrofitted in an existing waste-based CHP plant. The second and third case studies evaluate the feasibility of the current waste-based CHP plant to shift from cogeneration to polygeneration of biofuels, heat and power. In the fourth case study, a new process configuration is presented that couples AD of biodegradable waste with pyrolysis of lignocellulosic waste. The last case deals with the handling of digested sludge from WWTPs by the integration of thermochemical processes.The findings suggest that waste-integrated biorefineries can utilize infrastructure and products from existing waste industries through process integration and improve the overall process efficiencies and economics. Existing waste-based CHP plants can provide excess heat for integrated thermochemical processes; however, the modifications required are different for different gasifiers and pyrolyzers. Similarly, refuse-derived fuel (RDF) — processed from municipal solid waste (MSW) — can be utilized for production of various biofuels alongside heat and power without disturbing the operation of the CHP. But biomethane and dimethyl ether (DME) showed higher process feasibility than methanol and drop-in biofuels.The integration of pyrolysis with the AD process can almost double biomethane production compared with a standalone AD process, increasing efficiency to 67% from 52%. The integration is an attractive investment when off-site — rather than on-site — integration of pyrolysis and AD is considered.Drying of sludge digestate from wastewater treatment plants (WWTPs) is a bottleneck for its post-processing by thermochemical processes. However, waste heat from the existing CHP plant can be utilized for drying of sludge, which can also replace some of the boiler feed through co-incineration with waste biomass.The economic performance of waste-integrated biorefineries will depend on the volatility of market conditions. Finally, assessment of the effects of uncertainty of input data and process parameters on metrics of technical and economic performance is vital for evaluation of overall system performance.
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| 21. |
- Usman, M., et al.
(författare)
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Refining and reuse of waste lube oil in si engines : A novel approach for a sustainable environment
- 2021
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 14:10
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Tidskriftsartikel (refereegranskat)abstract
- The protection of the environment and pollution control are issues of paramount impor-tance. Researchers today are engrossed in mitigating the harmful impacts of petroleum waste on the environment. Lubricating oils, which are essential for the smooth operation of engines, are often disposed of improperly after completing their life. In the experimental work presented in this paper, deteriorated engine oil was regenerated using the acid treatment method and was reused in the engine. The comparison of the properties of reused oil, the engine’s performance, and the emissions from the engine are presented. The reuse of regenerated oil, the evaluation of performance, and emissions establish the usefulness of the regeneration of waste lubricating oil. For the used oil, total acid number (TAN), specific gravity, flash point, ash content, and kinematic viscosity changed by 60.7%, 6.7%, 4.4%, 96%, and 15.5%, respectively, compared with fresh oil. The regeneration partially restored all the lost lubricating oil properties. The performance parameters, brake power (BP), brake specific fuel consumption (BSFC), and exhaust gas temperature (EGT) improved with regenerated oil in use compared with used oil. The emissions CO and NOX contents for acid-treated oil were 9.7% and 17.3% less in comparison with used oil, respectively. Thus, regenerated oil showed improved performance and oil properties along with significantly reduced emissions when employed in an SI engine.
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| 22. |
- Wang, Jinshan, et al.
(författare)
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Integrating sludge drying in biomass fueled CHP plants
- 2021
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Ingår i: Energy, Ecology and Environment. - : Springer Science and Business Media LLC. - 2363-7692 .- 2363-8338. ; 6:1-12
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Tidskriftsartikel (refereegranskat)abstract
- Sludge handling through thermal conversion is environmentally friendly, which, however, requires sludge drying. This work proposed to use the waste heat of flue gas (FG) to dry sludge. The integration of sludge drying in biomass fueled CHP plants can clearly affect the performance of downstream processes in FG cleaning, such as flue gas quench (FGQ) and flue gas condenser (FGC). It can further affect the energy efficiency of (CHP). In order to understand the influence, a mathematical model and an Aspen PLUS model were developed to simulate the drying process and the CHP respectively. Based on simulation results, it has been found that the increase of feeding rate of sludge and the moisture content of sludge after drying can decrease the water evaporation in FGQ. An increase of the feeding rate of sludge in combination with a drop of moisture content of sludge after drying can decrease the heat recovery from FG. After sludge is dried, it can be used as fuel to replace part of the biomass fuels. The amount of biomass saving could be influenced by the dried sludge moisture content and flow rate. The simulation results of co-incineration biomass with sludge show that the moisture content of 40% after sludge drying leads to the maximum biomass saving.
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| 23. |
- Yan, Jinyue, 1959-, et al.
(författare)
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Waste Biorefineries : Advanced Design Concepts for Integrated Waste to Energy Processes
- 2023
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Waste Biorefineries: Advanced Design Concepts for Integrated Waste to Energy Processes presents a detailed guide to the design of energy-efficient and cost-effective waste-integrated biorefineries. Integrating thermochemical processing of waste with existing waste-to-energy technologies, the book includes the latest developments and technologies. It introduces current waste valorization techniques and examines reasons to modify existing waste-to-energy systems through the integration of new processes. In addition, the book explains the design of novel biorefineries and methods to assess these processes alongside detailed results, including the integration of waste-based CHP plants with waste gasification and the integration of pyrolysis technologies and biogas plants with waste thermochemical processing. Other sections discuss the issues and challenges of commercializing waste-to-energy technologies, including uncertainty in waste thermochemical process designs, the environmental impact of waste-integrated biorefineries, and the role of integrated waste-to-energy management in smart cities and urban energy systems. This book will be an invaluable reference for students, researchers and those in industry who are interested in the design and implementation of waste-to-energy systems, waste biomass-based combined heat and power plants, biogas plants and forest-based industries.
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