This page has only limited features, please log in for full access.
Biomass has emerged as one of the most promising renewable energy sources that can replace fossil fuels. Many researchers have carried out intensive research work on biomass gasification to evaluate its performance and feasibility to produce high-quality syngas. However, the process remains the problem of tar formation and low efficiency. Recently, novel approaches were developed for biomass utilization. Chemical looping gasification is considered a suitable pathway to produce valuable products from biomass among biomass conversion processes. This review paper provides a significant body of knowledge on the recent developments of the biomass-based chemical looping gasification process. The effects of process parameters have been discussed to provide important insights into the development of novel technology based on chemical looping. The state-of-the-art experimental and simulation/modeling studies and their fundamental assumptions are described in detail. In conclusion, the review paper highlights current research trends, identifying research gaps and opportunities for future applications of biomass-based chemical looping gasification process. The study aims to assist in understanding biomass-based chemical looping gasification and its development through recent research.
Nhut Nguyen; Falah Alobaid; Paul Dieringer; Bernd Epple. Biomass-Based Chemical Looping Gasification: Overview and Recent Developments. Applied Sciences 2021, 11, 7069 .
AMA StyleNhut Nguyen, Falah Alobaid, Paul Dieringer, Bernd Epple. Biomass-Based Chemical Looping Gasification: Overview and Recent Developments. Applied Sciences. 2021; 11 (15):7069.
Chicago/Turabian StyleNhut Nguyen; Falah Alobaid; Paul Dieringer; Bernd Epple. 2021. "Biomass-Based Chemical Looping Gasification: Overview and Recent Developments." Applied Sciences 11, no. 15: 7069.
Dynamic simulation provides an efficient approach for improving the efficiency of parabolic trough power plants and control circuits. In the dynamic simulation, the possibilities and operating conditions of the plant are evaluated regarding materials, processes, emissions, or economics. Several studies related to the dynamic simulation of the parabolic trough technology are summarised and discussed in this work. This study is the first research that presents a thorough description of the advanced control circuits used in the solar field and thermal storage system of a parabolic trough power plant. This power plant was implemented using advanced process simulation software (APROS). The dynamic model was built based on the real specifications of the power plant.
Wisam Al-Maliki; Nabeel Mahmoud; Hussein Al-Khafaji; Falah Alobaid; Bernd Epple. Design and Implementation of the Solar Field and Thermal Storage System Controllers for a Parabolic Trough Solar Power Plant. Applied Sciences 2021, 11, 6155 .
AMA StyleWisam Al-Maliki, Nabeel Mahmoud, Hussein Al-Khafaji, Falah Alobaid, Bernd Epple. Design and Implementation of the Solar Field and Thermal Storage System Controllers for a Parabolic Trough Solar Power Plant. Applied Sciences. 2021; 11 (13):6155.
Chicago/Turabian StyleWisam Al-Maliki; Nabeel Mahmoud; Hussein Al-Khafaji; Falah Alobaid; Bernd Epple. 2021. "Design and Implementation of the Solar Field and Thermal Storage System Controllers for a Parabolic Trough Solar Power Plant." Applied Sciences 11, no. 13: 6155.
The combined cycle power plants are the most recognized thermal power plants for their high efficiency, fast start-up capability, and relatively low environmental impact. Moreover, their flexible unit dispatch supports the share of renewable energy, which contributes to carbon mitigation. The operational flexibility of Integrated Solar Combined Cycle (ISCC) power plants is a crucial factor for reliable grid stability. To evaluate the limitations and capabilities of ISCC power plants and their control structures, dynamic simulation is a feasible method. In this study, a sophisticated dynamic process model of the ISCC power plant in Kuraymat, Egypt, has been developed using APROS software. The model describes the plant with a high level of detail including the solar field, the heat recovery steam generator, and the control structures. The model was implemented structurally identical to the reference plant and tuned using the operational design data. Actual measurements were used as the basis for the initialization and validation of the dynamic simulation environment. Dynamic analysis of four different days was performed, then the simulation results were presented and compared with actual measurements. The comparison showed that the course of the actual measurements could be predicted with high accuracy. The solar field influences and the system’s overall power curves are reliably simulated. Consequently, the validated model can simulate the dynamic behavior of the ISCC power plant with a high degree of accuracy, and can be considered in future planning decisions.
Ayman Temraz; Falah Alobaid; Jerome Link; Ahmed Elweteedy; Bernd Epple. Development and Validation of a Dynamic Simulation Model for an Integrated Solar Combined Cycle Power Plant. Energies 2021, 14, 3304 .
AMA StyleAyman Temraz, Falah Alobaid, Jerome Link, Ahmed Elweteedy, Bernd Epple. Development and Validation of a Dynamic Simulation Model for an Integrated Solar Combined Cycle Power Plant. Energies. 2021; 14 (11):3304.
Chicago/Turabian StyleAyman Temraz; Falah Alobaid; Jerome Link; Ahmed Elweteedy; Bernd Epple. 2021. "Development and Validation of a Dynamic Simulation Model for an Integrated Solar Combined Cycle Power Plant." Energies 14, no. 11: 3304.
The conventional design of circulating fluidized beds mainly focuses on high process efficiency, while electricity markets increasingly target operating flexibility due to the increased penetration of renewable energy sources. In this work, the operational flexibility of the CFB furnace when applied to compensate for the feed-in fluctuations from renewable energies has been investigated experimentally. Employing a 1 MWth CFB test facility, Polish lignite was combusted over a wide range of transient operating conditions. The profiles of temperatures and pressures along the riser, the flue gas concentration and the temperature developments in the bed zone, and the outlet of the cyclone that identify the basis for operational flexibility and scale-up studies were shown. It was found that the circulating fluidized bed furnace can be operated with higher positive and negative load change rates up to ±25%/min, maintaining high combustion efficiency and low emissions. Furthermore, the temperature distribution along the riser was almost homogeneous at higher loads. By reducing the load, the temperature difference in the bed zone and after the cyclone was decreased and heterogeneous temperature distribution along the riser can be observed, resulting in a slight decrease in the combustion efficiency.
Falah Alobaid; Jens Peters; Bernd Epple. Experimental measurements for Polish lignite combustion in a 1 MWth circulating fluidized bed during load changes. Energy 2021, 228, 120585 .
AMA StyleFalah Alobaid, Jens Peters, Bernd Epple. Experimental measurements for Polish lignite combustion in a 1 MWth circulating fluidized bed during load changes. Energy. 2021; 228 ():120585.
Chicago/Turabian StyleFalah Alobaid; Jens Peters; Bernd Epple. 2021. "Experimental measurements for Polish lignite combustion in a 1 MWth circulating fluidized bed during load changes." Energy 228, no. : 120585.
A comprehensive process model is proposed to simulate the steam gasification of biomass in a bubbling fluidized bed reactor using the Aspen Plus simulator. The reactor models are implemented using external FORTRAN codes for hydrodynamic and reaction kinetic calculations. Governing hydrodynamic equations and kinetic reaction rates for char gasification and water-gas shift reactions are obtained from experimental investigations and the literature. Experimental results at different operating conditions from steam gasification of torrefied biomass in a pilot-scale gasifier are used to validate the process model. Gasification temperature and steam-to-biomass ratio promote hydrogen production and improve process efficiencies. The steam-to-biomass ratio is directly proportional to an increase in the content of hydrogen and carbon monoxide, while gas yield and carbon conversion efficiency enhance significantly with increasing temperature. The model predictions are in good agreement with experimental data. The mean error of CO2 shows the highest value of 0.329 for the steam-to-biomass ratio and the lowest deviation is at 0.033 of carbon conversion efficiency, respectively. The validated model is capable of simulating biomass gasification under various operating conditions.
Nhut Nguyen; Falah Alobaid; Bernd Epple. Process Simulation of Steam Gasification of Torrefied Woodchips in a Bubbling Fluidized Bed Reactor Using Aspen Plus. Applied Sciences 2021, 11, 2877 .
AMA StyleNhut Nguyen, Falah Alobaid, Bernd Epple. Process Simulation of Steam Gasification of Torrefied Woodchips in a Bubbling Fluidized Bed Reactor Using Aspen Plus. Applied Sciences. 2021; 11 (6):2877.
Chicago/Turabian StyleNhut Nguyen; Falah Alobaid; Bernd Epple. 2021. "Process Simulation of Steam Gasification of Torrefied Woodchips in a Bubbling Fluidized Bed Reactor Using Aspen Plus." Applied Sciences 11, no. 6: 2877.
Absorption refrigeration cycle is considered a vital option for thermal cooling processes. Designing new systems is needed to meet the increasing communities’ demands of space cooling. This should be given more attention especially with the increasing conventional fossil fuel energy costs and CO2 emission. This work presents the thermo-economic analysis to compare between different solar absorption cooling system configurations. The proposed system combines a solar field, flashing tank and absorption chiller: two types of absorption cycle H2O-LiBr and NH3-H2O have been compared to each other by parabolic trough collectors and evacuated tube collectors under the same operating conditions. A case study of 200 TR total cooling load is also presented. Results reveal that parabolic trough collector combined with H2O-LiBr (PTC/H2O-LiBr) gives lower design aspects and minimum rates of hourly costs (5.2 $/h) followed by ETC/H2O-LiBr configuration (5.6 $/h). H2O-LiBr gives lower thermo-economic product cost (0.14 $/GJ) compared to the NH3-H2O (0.16 $/GJ). The absorption refrigeration cycle coefficient of performance ranged between 0.5 and 0.9.
Adil Al-Falahi; Falah Alobaid; Bernd Epple. Thermo-Economic Comparisons of Environmentally Friendly Solar Assisted Absorption Air Conditioning Systems. Applied Sciences 2021, 11, 2442 .
AMA StyleAdil Al-Falahi, Falah Alobaid, Bernd Epple. Thermo-Economic Comparisons of Environmentally Friendly Solar Assisted Absorption Air Conditioning Systems. Applied Sciences. 2021; 11 (5):2442.
Chicago/Turabian StyleAdil Al-Falahi; Falah Alobaid; Bernd Epple. 2021. "Thermo-Economic Comparisons of Environmentally Friendly Solar Assisted Absorption Air Conditioning Systems." Applied Sciences 11, no. 5: 2442.
The world society ratifies international measures to reach a flexible and low-carbon energy economy, attenuating climate change and its devastating environmental consequences. The main contribution of this Special Issue is related to thermochemical conversion technologies of solid fuels (e.g., biomass, refuse-derived fuel, and sewage sludge), in particular via combustion and gasification. Here, the recent activities on operational flexibility of co-combustion of biomass and lignite, carbon capture methods, solar-driven air-conditioning systems, integrated solar combined cycle power plants, and advanced gasification systems, such as the sorption-enhanced gasification and the chemical looping gasification, are shown.
Falah Alobaid; Jochen Ströhle. Special Issue “Thermochemical Conversion Processes for Solid Fuels and Renewable Energies”. Applied Sciences 2021, 11, 1907 .
AMA StyleFalah Alobaid, Jochen Ströhle. Special Issue “Thermochemical Conversion Processes for Solid Fuels and Renewable Energies”. Applied Sciences. 2021; 11 (4):1907.
Chicago/Turabian StyleFalah Alobaid; Jochen Ströhle. 2021. "Special Issue “Thermochemical Conversion Processes for Solid Fuels and Renewable Energies”." Applied Sciences 11, no. 4: 1907.
The main objective of this paper is to simulate solar absorption cooling systems that use ammonia mixture as a working fluid to produce cooling. In this study, we have considered different configurations based on the ammonia–water (NH3–H2O) cooling cycle depending on the solar thermal technology: Evacuated tube collectors (ETC) and parabolic trough (PTC) solar collectors. To compare the configurations we have performed the energy, exergy, and economic analysis. The effect of heat source temperature on the critical parameters such as coefficient of performance (COP) and exegetic efficiency has been investigated for each configuration. Furthermore, the required optimum area and associated cost for each collector type have been determined. The methodology is applied in a specific case study for a sports arena with a 700~800 kW total cooling load. Results reveal that (PTC/NH3-H2O)configuration gives lower design aspects and minimum rates of hourly costs (USD 11.3/h) while (ETC/NH3-H2O) configuration (USD 12.16/h). (ETC/NH3-H2O) gives lower thermo-economic product cost (USD 0.14/GJ). The cycle coefficient of performance (COP) (of 0.5).
Adil Al-Falahi; Falah Alobaid; Bernd Epple. Thermo-Economic Evaluation of Aqua-Ammonia Solar Absorption Air Conditioning System Integrated with Various Collector Types. Entropy 2020, 22, 1165 .
AMA StyleAdil Al-Falahi, Falah Alobaid, Bernd Epple. Thermo-Economic Evaluation of Aqua-Ammonia Solar Absorption Air Conditioning System Integrated with Various Collector Types. Entropy. 2020; 22 (10):1165.
Chicago/Turabian StyleAdil Al-Falahi; Falah Alobaid; Bernd Epple. 2020. "Thermo-Economic Evaluation of Aqua-Ammonia Solar Absorption Air Conditioning System Integrated with Various Collector Types." Entropy 22, no. 10: 1165.
The share of power from fluctuating renewable energies such as wind and solar is increasing due to the ongoing climate change. It is therefore essential to use technologies that can compensate for these fluctuations. Experiments at 1 MWth scale were carried out to evaluate the operational flexibility of a circulating fluidized bed (CFB) combustor during transient operation from 60% to 100% load. A typical load following sequence for fluctuating electricity generation/demand was reproduced experimentally by performing 4 load changes. The hydrodynamic condition after a load change depends on if the load change was in positive or negative direction due to the heat stored in the refractory/bed material at high loads and released when the load decreases. A 1.5D-process simulation model was created in the software APROS (Advanced Process Simulation) with the target of showing the specific characteristics of a CFB furnace during load following operation. The model was tuned with experimental data of a steady-state test point and validated with the load cycling tests. The simulation results show the key characteristics of CFB combustion with reasonable accuracy. Detailed experimental data is presented and a core-annulus approach for the modeling of the CFB furnace is used.
Jens Peters; Falah Alobaid; Bernd Epple. Operational Flexibility of a CFB Furnace during Fast Load Change—Experimental Measurements and Dynamic Model. Applied Sciences 2020, 10, 5972 .
AMA StyleJens Peters, Falah Alobaid, Bernd Epple. Operational Flexibility of a CFB Furnace during Fast Load Change—Experimental Measurements and Dynamic Model. Applied Sciences. 2020; 10 (17):5972.
Chicago/Turabian StyleJens Peters; Falah Alobaid; Bernd Epple. 2020. "Operational Flexibility of a CFB Furnace during Fast Load Change—Experimental Measurements and Dynamic Model." Applied Sciences 10, no. 17: 5972.
In this study, a sophisticated dynamic process model of a circulating fluidized bed furnace has been developed. The model describes the 1 MWth test facility, erected at the Technical University of Darmstadt, with a high level of detail including the air supply, the circulating fluidized bed, the flue gas path, the water-cooling system, and the control structures. The developed model was tuned using the experimental data at 82% load. After that, the load is decreased to 63% and the obtained numerical results were compared with the measurement data. Then, the dynamic load increases from 63% to 88% to 100%, followed by dynamic load decreases from 100% to 89% to 68% were simulated. During the load change, the pressure and temperature profiles along the riser were compared with measurement data, showing good agreement. Furthermore, the flue gas concentrations at the outlet of the cyclone agree very well with the values of the test facility. Using the validated model, the transient behaviour of the process variables (pressure, temperature, composition, and mass flow rates) of solids and gas flows during the combustion can be determined. Furthermore, the solid circulating, the inertia, and a variety of parameters that cannot be fully measured in the test facility were numerically obtained.
Falah Alobaid; Jens Peters; Rami Amro; Bernd Epple. Dynamic process simulation for Polish lignite combustion in a 1 MWth circulating fluidized bed during load changes. Applied Energy 2020, 278, 115662 .
AMA StyleFalah Alobaid, Jens Peters, Rami Amro, Bernd Epple. Dynamic process simulation for Polish lignite combustion in a 1 MWth circulating fluidized bed during load changes. Applied Energy. 2020; 278 ():115662.
Chicago/Turabian StyleFalah Alobaid; Jens Peters; Rami Amro; Bernd Epple. 2020. "Dynamic process simulation for Polish lignite combustion in a 1 MWth circulating fluidized bed during load changes." Applied Energy 278, no. : 115662.
Solar-assisted combined cycle power plants (CCPPs) feature the advantages of renewable clean energy with efficient CCPPs. These power plants integrate a solar field with a CCPP. This integration increases the efficiency of solar power plants while decreasing the CO2 emissions of the CCPPs. In this paper, energy and exergy analyses were performed for an existing solar-assisted CCPP. The overall thermal efficiency and the exergetic efficiency of each component in the power plant were calculated for different solar field capacities. Also, a parametric study of the power plant was performed. The analysis indicated that the exergetic efficiency of the power plant components has its lowest value in the solar field while the condenser has the lowest exergetic efficiency in the combined cycle regime of operation. Further, a parametric study revealed that the thermal efficiency and the exergetic efficiency of the power plant as a whole decrease with increasing ambient temperature and have their highest values in the combined cycle regime of operation. Owing to these results, an investigation into the sources of exergy destruction in the solar field was conducted.
Ayman Temraz; Ahmed Rashad; Ahmed Elweteedy; Falah Alobaid; Bernd Epple. Energy and Exergy Analyses of an Existing Solar-Assisted Combined Cycle Power Plant. Applied Sciences 2020, 10, 4980 .
AMA StyleAyman Temraz, Ahmed Rashad, Ahmed Elweteedy, Falah Alobaid, Bernd Epple. Energy and Exergy Analyses of an Existing Solar-Assisted Combined Cycle Power Plant. Applied Sciences. 2020; 10 (14):4980.
Chicago/Turabian StyleAyman Temraz; Ahmed Rashad; Ahmed Elweteedy; Falah Alobaid; Bernd Epple. 2020. "Energy and Exergy Analyses of an Existing Solar-Assisted Combined Cycle Power Plant." Applied Sciences 10, no. 14: 4980.
The influence of pressure on the gas/liquid interfacial area is investigated in the pressure range of 0.2–0.3 MPa by using a tray column test rig. A simulated waste gas, which consisted of 30% CO2 and 70% air, was used in this study. Distilled water was employed as an absorbent. The temperature of the inlet water was 19 °C. The inlet volumetric flow rate of water was 0.17 m3/h. Two series of experiments were performed; the first series was performed at inlet gas flow rate 15 Nm3/h, whereas the second series was at 20 Nm3/h of inlet gas flow rate. The results showed that the gas/liquid interfacial area decreases when the total pressure is increased. The effect of pressure on the gas/liquid interfacial area at high inlet volumetric gas flow rates is more significant than at low inlet volumetric gas flow rates. The authors studied the effect of decreasing the interfacial area on the performance of a tray column for CO2 capture.
Adel Almoslh; Falah Alobaid; Christian Heinze; Bernd Epple. Influence of Pressure on Gas/Liquid Interfacial Area in a Tray Column. Applied Sciences 2020, 10, 4617 .
AMA StyleAdel Almoslh, Falah Alobaid, Christian Heinze, Bernd Epple. Influence of Pressure on Gas/Liquid Interfacial Area in a Tray Column. Applied Sciences. 2020; 10 (13):4617.
Chicago/Turabian StyleAdel Almoslh; Falah Alobaid; Christian Heinze; Bernd Epple. 2020. "Influence of Pressure on Gas/Liquid Interfacial Area in a Tray Column." Applied Sciences 10, no. 13: 4617.
Chemical looping gasification (CLG) is a novel gasification technique, allowing for the production of a nitrogen-free high calorific synthesis gas from solid hydrocarbon feedstocks, without requiring a costly air separation unit. Initial advances to better understand the CLG technology were made during first studies in lab and bench scale units and through basic process simulations. Yet, tailored process control strategies are required for larger CLG units, which are not equipped with auxiliary heating. Here, it becomes a demanding task to achieve autothermal CLG operation, for which stable reactor temperatures are obtained. This study presents two avenues to attain autothermal CLG behavior, established through equilibrium based process simulations. As a first approach, the dilution of active oxygen carrier materials with inert heat carriers to limit oxygen transport to the fuel reactor has been investigated. Secondly, the suitability of restricting the air flow to the air reactor in order to control the oxygen availability in the fuel reactor was examined. Process simulations show that both process control approaches facilitate controlled and de-coupled heat and oxygen transport between the two reactors of the chemical looping gasifier, thus allowing for efficient autothermal CLG operation. With the aim of inferring general guidelines on how CLG units have to be operated in order to achieve decent synthesis gas yields, different advantages and disadvantages associated to the two suggested process control strategies are discussed in detail and optimization avenues are presented.
Paul Dieringer; Falko Marx; Falah Alobaid; Jochen Ströhle; Bernd Epple. Process Control Strategies in Chemical Looping Gasification—A Novel Process for the Production of Biofuels Allowing for Net Negative CO2 Emissions. Applied Sciences 2020, 10, 4271 .
AMA StylePaul Dieringer, Falko Marx, Falah Alobaid, Jochen Ströhle, Bernd Epple. Process Control Strategies in Chemical Looping Gasification—A Novel Process for the Production of Biofuels Allowing for Net Negative CO2 Emissions. Applied Sciences. 2020; 10 (12):4271.
Chicago/Turabian StylePaul Dieringer; Falko Marx; Falah Alobaid; Jochen Ströhle; Bernd Epple. 2020. "Process Control Strategies in Chemical Looping Gasification—A Novel Process for the Production of Biofuels Allowing for Net Negative CO2 Emissions." Applied Sciences 10, no. 12: 4271.
Solar absorption cycles for air conditioning systems have recently attracted much attention. They have some important advantages that aid in reducing greenhouse gas emissions. In this work, design and thermo-economic analyses are presented in order to compare between two different collector types (parabolic trough and evacuated tube) by water–lithium bromide absorption systems, and to select the best operating conditions. Generally, the system consists of three major parts. The first part is the solar field for thermal power conversion. The second part is the intermediate cycle, which contains a flashing tank and pumping system. The third part is the water lithium bromide absorption chiller. A case study for a sports arena with 700–800 kW total cooling load is also presented. Results reveal that a parabolic trough collector combined with H2O–LiBr (PTC/H2O–LiBr) gives lower design aspects and minimum rates of hourly costs (USD 5.2/h), while ETC/H2O–LiBr configuration give USD 5.6/h. The H2O–LiBr thermo-economic product cost is USD 0.14/GJ. The cycle coefficient of performance COP was in the range of 0.5 to 0.9.
Adil Al-Falahi; Falah Alobaid; Bernd Epple. Design and Thermo-Economic Comparisons of an Absorption Air Conditioning System Based on Parabolic Trough and Evacuated Tube Solar Collectors. Energies 2020, 13, 3198 .
AMA StyleAdil Al-Falahi, Falah Alobaid, Bernd Epple. Design and Thermo-Economic Comparisons of an Absorption Air Conditioning System Based on Parabolic Trough and Evacuated Tube Solar Collectors. Energies. 2020; 13 (12):3198.
Chicago/Turabian StyleAdil Al-Falahi; Falah Alobaid; Bernd Epple. 2020. "Design and Thermo-Economic Comparisons of an Absorption Air Conditioning System Based on Parabolic Trough and Evacuated Tube Solar Collectors." Energies 13, no. 12: 3198.
The electrical power consumption of refrigeration equipment leads to a significant influence on the supply network, especially on the hottest days during the cooling season (and this is besides the conventional electricity problem in Iraq). The aim of this work is to investigate the energy performance of a solar-driven air-conditioning system utilizing absorption technology under climate in Baghdad, Iraq. The solar fraction and the thermal performance of the solar air-conditioning system were analyzed for various months in the cooling season. It was found that the system operating in August shows the best monthly average solar fraction (of 59.4%) and coefficient of performance (COP) (of 0.52) due to the high solar potential in this month. Moreover, the seasonal integrated collector efficiency was 54%, providing a seasonal solar fraction of 58%, and the COP of the absorption chiller was 0.44, which was in limit, as reported in the literature for similar systems. A detailed parametric analysis was carried out to evaluate the thermal performance of the system and analyses, and the effect of design variables on the solar fraction of the system during the cooling season.
Adil Al-Falahi; Falah Alobaid; Bernd Epple. A New Design of an Integrated Solar Absorption Cooling System Driven by an Evacuated Tube Collector: A Case Study for Baghdad, Iraq. Applied Sciences 2020, 10, 3622 .
AMA StyleAdil Al-Falahi, Falah Alobaid, Bernd Epple. A New Design of an Integrated Solar Absorption Cooling System Driven by an Evacuated Tube Collector: A Case Study for Baghdad, Iraq. Applied Sciences. 2020; 10 (10):3622.
Chicago/Turabian StyleAdil Al-Falahi; Falah Alobaid; Bernd Epple. 2020. "A New Design of an Integrated Solar Absorption Cooling System Driven by an Evacuated Tube Collector: A Case Study for Baghdad, Iraq." Applied Sciences 10, no. 10: 3622.
In this study two mathematical models, rate-based and equilibrium-stage models in Aspen Plus process simulator, were used to simulate the tar absorption processes using soybean oil as a solvent in a research lab-scale experiment. The matching between simulation results and experimental data shows a good agreement. The simulation results predicted by the rate-based model show a higher level of agreement than the equilibrium model compared with the experimental data. Analysis study of tar absorption process was carried out which revealed the effect of temperature and flow rate on the soybean oil, and height-packed bed on tar removal efficiency. The methodology of selecting the optimum (most economical) operation conditions has also been performed in this study.
Adel Almoslh; Falah Alobaid; Christian Heinze; Bernd Epple. Comparison of Equilibrium-Stage and Rate-Based Models of a Packed Column for Tar Absorption Using Vegetable Oil. Applied Sciences 2020, 10, 2362 .
AMA StyleAdel Almoslh, Falah Alobaid, Christian Heinze, Bernd Epple. Comparison of Equilibrium-Stage and Rate-Based Models of a Packed Column for Tar Absorption Using Vegetable Oil. Applied Sciences. 2020; 10 (7):2362.
Chicago/Turabian StyleAdel Almoslh; Falah Alobaid; Christian Heinze; Bernd Epple. 2020. "Comparison of Equilibrium-Stage and Rate-Based Models of a Packed Column for Tar Absorption Using Vegetable Oil." Applied Sciences 10, no. 7: 2362.
Gabriele Sabia; Christian Heinze; Falah Alobaid; Emanuele Martelli; Bernd Epple. ASPEN dynamics simulation for combined cycle power plant – Validation with hot start-up measurement. Energy 2019, 187, 1 .
AMA StyleGabriele Sabia, Christian Heinze, Falah Alobaid, Emanuele Martelli, Bernd Epple. ASPEN dynamics simulation for combined cycle power plant – Validation with hot start-up measurement. Energy. 2019; 187 ():1.
Chicago/Turabian StyleGabriele Sabia; Christian Heinze; Falah Alobaid; Emanuele Martelli; Bernd Epple. 2019. "ASPEN dynamics simulation for combined cycle power plant – Validation with hot start-up measurement." Energy 187, no. : 1.
Biogenic residues upgraded by torrefaction are well suited for co-firing in existing thermal power plants due to their increased net calorific value, their improved grindability and their good characteristics regarding storage and transport. In this work, torrefied and pelletized biomass (coniferous wood sawdust) and hard coal (Columbian Calenturitas) were co-combusted in a 1 MWth pulverized coal-fired furnace. The mixture of both fuels (torrefied biomass and hard coal) was co-grinded at two ratios with a thermal share of biomass of 3.8 % and 7.3 % using the same coal mill. For comparison purpose, experiments on pure hard coal combustion (only coal) were carried out, too. Despite torrefaction, the throughput of the mill was sharply reduced at higher biomass shares and the average grain size of pulverized fuel was increased. However, both fuel blends were co-combusted without any difficulty. Compared to mono-combustion of the hard coal, no significant differences were detected, neither in the flue gas emissions nor in the char burnout. Gas measurements in the flame profile show higher levels of released volatile matter close to the burner, resulting in a higher oxygen demand.
Falah Alobaid; Jan-Peter Busch; Alexander Stroh; Jochen Ströhle; Bernd Epple. Experimental measurements for torrefied biomass Co-combustion in a 1 MWth pulverized coal-fired furnace. Journal of the Energy Institute 2019, 93, 833 -846.
AMA StyleFalah Alobaid, Jan-Peter Busch, Alexander Stroh, Jochen Ströhle, Bernd Epple. Experimental measurements for torrefied biomass Co-combustion in a 1 MWth pulverized coal-fired furnace. Journal of the Energy Institute. 2019; 93 (3):833-846.
Chicago/Turabian StyleFalah Alobaid; Jan-Peter Busch; Alexander Stroh; Jochen Ströhle; Bernd Epple. 2019. "Experimental measurements for torrefied biomass Co-combustion in a 1 MWth pulverized coal-fired furnace." Journal of the Energy Institute 93, no. 3: 833-846.
A cold flow circulating fluidized bed (CFB) reactor is simulated under three fluidization velocities with the coarse grain discrete element method (DEM) using two different polydisperse particle systems namely glass beads and slightly coarser sand particles of Geldart A-B range. Particle velocities and particle concentration were measured by capacitance probe for the validation of the numerical model. The simulations were carried out using a homogenous drag model and a structure dependent drag model using the theory of energy minimization multiscale method (EMMS). Numerical parameters like grid resolution and computational time were investigated for the coarse grain CFD-DEM model, suggesting a cell uniformity criteria that might lead to more mesh independent results. The simulated macroscopic quantities such as pressure profile are generally in good agreement for all simulated cases using the EMMS model. Microscopic quantities such as particles velocities and solids concentration are partially matched well with the experimental data. The qualitative profiles of particle velocity and particle concentration are in better agreement for the EMMS model than for the homogenous drag model. The simulated reactor outflux using glass beads is well matched with experiment. The simulated reactor outflux with sand material is overestimated with EMMS model, although not that strong as for the Gidaspow model, in comparison to experimental measurements. One reason for the discrepancy is due to the cluster diameter correlation that require further development to be applicable in turbulent fluidization flow regime. Further model improvements are discussed and solutions are provided.
Alexander Stroh; Alexander Daikeler; Markku Nikku; Jan May; Falah Alobaid; Maximilian von Bohnstein; Jochen Ströhle; Bernd Epple. Coarse grain 3D CFD-DEM simulation and validation with capacitance probe measurements in a circulating fluidized bed. Chemical Engineering Science 2018, 196, 37 -53.
AMA StyleAlexander Stroh, Alexander Daikeler, Markku Nikku, Jan May, Falah Alobaid, Maximilian von Bohnstein, Jochen Ströhle, Bernd Epple. Coarse grain 3D CFD-DEM simulation and validation with capacitance probe measurements in a circulating fluidized bed. Chemical Engineering Science. 2018; 196 ():37-53.
Chicago/Turabian StyleAlexander Stroh; Alexander Daikeler; Markku Nikku; Jan May; Falah Alobaid; Maximilian von Bohnstein; Jochen Ströhle; Bernd Epple. 2018. "Coarse grain 3D CFD-DEM simulation and validation with capacitance probe measurements in a circulating fluidized bed." Chemical Engineering Science 196, no. : 37-53.
Chemical–looping combustion (CLC) is a promising oxyfuel carbon capture technology consisting of two interconnected fluidized beds with a metal oxide as a bed material/oxygen carrier. The particles, which circulate between both reactors, firstly absorb oxygen in the air reactor (AR) and secondly provide the oxygen for the combustion in the fuel reactor (FR). In this work, CFD simulation models for fuel and air reactor of the world’s second–largest CLC pilot plant at Technische Universität Darmstadt have been developed. An in–house thermochemical reaction model is combined with the two–fluid model implemented in ANSYS–FLUENT to simulate the gas-solid interaction of the FR and AR of the 1 MWth chemical–looping combustion pilot plant. All reactions, including the pyrolysis of coal, the gasification and oxidation of char and the reactions of the oxygen carrier are included by customized user defined functions (UDF). Stable, transient simulations of 55 s (FR) and 50 s (AR) were carried out. The FR simulation is showing a good agreement towards experimental measurements for the pressure drop. However, deviations occur in the gas composition between the simulation and the experimental data. Good agreement is obtained for the gas composition and the temperature in the AR. Slight discrepancies occur in the pressure profile between the numerical and experimental data. Possible reasons for deviations are discussed and appropriate solutions provided.
Jan May; Falah Alobaid; Peter Ohlemüller; Alexander Stroh; Jochen Ströhle; Bernd Epple. Reactive two–fluid model for chemical–looping combustion – Simulation of fuel and air reactors. International Journal of Greenhouse Gas Control 2018, 76, 175 -192.
AMA StyleJan May, Falah Alobaid, Peter Ohlemüller, Alexander Stroh, Jochen Ströhle, Bernd Epple. Reactive two–fluid model for chemical–looping combustion – Simulation of fuel and air reactors. International Journal of Greenhouse Gas Control. 2018; 76 ():175-192.
Chicago/Turabian StyleJan May; Falah Alobaid; Peter Ohlemüller; Alexander Stroh; Jochen Ströhle; Bernd Epple. 2018. "Reactive two–fluid model for chemical–looping combustion – Simulation of fuel and air reactors." International Journal of Greenhouse Gas Control 76, no. : 175-192.