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Prof. Juma Haydary
Institute of chemical and environment engineering, Department of chemical and biochemical engineering

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0 Biomass Conversion
0 Chemical Engineering
0 Gasification
0 Process Design
0 Pyrolysis

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Pyrolysis
Gasification
Process Design

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Short Biography

Juma Haydary is a professor and head of the department of chemical and biochemical engineering at the Slovak University of Technology in Bratislava. Fields of teaching: Chemical process design and simulation process intensification, separation processes, unit operations, cost engineering Fields of research: Pyrolysis and gasification of waste and biomass, properties of polymers, catalytic hydrocracking of heavy oil fractions, process design and intensification.

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Journal article
Published: 24 April 2021 in Journal of Environmental Chemical Engineering
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As in every complex technological process design, pyrolysis reactor design and optimization require a mathematical model of sufficient complexity. Aside from properties of utilized feedstock, reaction temperature and residence time of solid and gaseous phase are the main parameters in pyrolysis reactor design. Screw pyrolysis reactor, also known as auger reactor, is a well-known and studied reactor type suitable for pyrolysis of heterogeneous materials. In this work, a complex mathematical model of a screw pyrolysis reactor coupled with a particle model is proposed. Primary pyrolysis reactions as well as secondary tar cracking reactions were taken into account. In addition, heat and mass transfer inside a solid particle and heat transfer between both phases and the reactor wall were considered. Experimental results obtained at a pyrolyzer temperature of 650, 700 and 750 °C and residence time of solid phase of 7, 9.6 and 15 min were compared with data predicted by the mathematical model. Both, tar and gas yield predicted by the model at 700 and 750 °C showed a good agreement with experimental data at all solid phase residence times. However, the model predicted higher gas production compared to the experimental one at 650 °C. The value of relative deviation of char yield remained under 2% under all pyrolysis conditions. The proposed model can be used for simulation and optimization of industry-scale screw pyrolyzers. However, its validity should be verified on wider operation temperature range.

ACS Style

Jakub Husár; Patrik Šuhaj; Juma Haydary. Experimental validation of complex mathematical model of screw reactor coupled with particle model describing pyrolysis of lignocellulosic biomass. Journal of Environmental Chemical Engineering 2021, 9, 105543 .

AMA Style

Jakub Husár, Patrik Šuhaj, Juma Haydary. Experimental validation of complex mathematical model of screw reactor coupled with particle model describing pyrolysis of lignocellulosic biomass. Journal of Environmental Chemical Engineering. 2021; 9 (4):105543.

Chicago/Turabian Style

Jakub Husár; Patrik Šuhaj; Juma Haydary. 2021. "Experimental validation of complex mathematical model of screw reactor coupled with particle model describing pyrolysis of lignocellulosic biomass." Journal of Environmental Chemical Engineering 9, no. 4: 105543.

Journal article
Published: 13 February 2021 in Processes
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Gasification is a promising technology for the conversion of mixed solid waste like refuse-derived fuel (RDF) and municipal solid waste (MSW) into a valuable gas consisting of H2, CO, CH4 and CO2. This work aims to identify the basic challenges of a single-stage batch gasification system related to tar and wax content in the producer gas. RDF was first gasified in a simple semi-batch laboratory-scale gasification reactor. A significant yield of tars and waxes was received in the produced gas. Waxes were analyzed using gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectrometry. These analyses indicated the presence of polyethylene and polypropylene chains. The maximum content of H2 and CO was measured 500 seconds after the start of the process. In a second series of experiments, a secondary catalytic stage with an Ni-doped clay catalyst was installed. In the two-stage catalytic process, no waxes were captured in isopropanol and the total tar content decreased by approximately 90 %. A single one-stage semi-batch gasification system is not suitable for RDF gasification; a large fraction of tar and waxes can be generated which can cause fouling in downstream processes. A secondary catalytic stage can significantly reduce the tar content in gas.

ACS Style

Juma Haydary; Patrik Šuhaj; Michal Šoral. Semi-Batch Gasification of Refuse-Derived Fuel (RDF). Processes 2021, 9, 343 .

AMA Style

Juma Haydary, Patrik Šuhaj, Michal Šoral. Semi-Batch Gasification of Refuse-Derived Fuel (RDF). Processes. 2021; 9 (2):343.

Chicago/Turabian Style

Juma Haydary; Patrik Šuhaj; Michal Šoral. 2021. "Semi-Batch Gasification of Refuse-Derived Fuel (RDF)." Processes 9, no. 2: 343.

Journal article
Published: 27 November 2020 in Processes
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This work represents an experimental study and mathematical modeling of convective apple slice drying. The influence of multiple process parameters such as temperature, air humidity, air velocity and slice thickness on process kinetics, product water activity and parameters of empirical models has been investigated. Drying characteristics of apple slices were monitored at temperatures of 40, 45 and 50 °C, air velocities of 0.6, 0.85 and 1.1 m/s., slice thicknesses of 4, 6, 8, 10 and 12 mm, and in relative air humidity ranges of 25–28, 35–38 and 40–45%. During the process, samples were dried from an initial moisture content of 86.7% to that of 20% (w.b), corresponding to product water activity of 0.45 ± 0.05. By increasing the temperature from 40 to 50 °C, the time for reaching the required product water activity decreased by about 300 min. Sample thickness is the most significant parameter; by increasing the slice thickness from 4 to 12 mm, the time required to achieve the required water activity increased by more than 500 min. For all experimental runs, parameters of five different thin-layer empirical models were estimated. A thin-layer model sensible to process conditions such as temperature, air velocity, layer thickness and air relative humidity was developed and statistically analyzed.

ACS Style

Mohammad Jafar Royen; Abdul Wasim Noori; Juma Haydary. Experimental Study and Mathematical Modeling of Convective Thin-Layer Drying of Apple Slices. Processes 2020, 8, 1562 .

AMA Style

Mohammad Jafar Royen, Abdul Wasim Noori, Juma Haydary. Experimental Study and Mathematical Modeling of Convective Thin-Layer Drying of Apple Slices. Processes. 2020; 8 (12):1562.

Chicago/Turabian Style

Mohammad Jafar Royen; Abdul Wasim Noori; Juma Haydary. 2020. "Experimental Study and Mathematical Modeling of Convective Thin-Layer Drying of Apple Slices." Processes 8, no. 12: 1562.

Journal article
Published: 03 November 2020 in Forests
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Research Highlights: As to fill the current knowledge gap and to deliver important findings to the scientific community, efficient sulfur recovery from black liquor gasifier syngas, comprising both gas cleaning and returning sulfur to the pulping process, was modeled and assessed from a techno-economic viewpoint. This manuscript proves that the associated investment and operational costs cannot be neglected and that they impact the black liquor gasification feasibility significantly. To prove its gasification as a sustainable and more efficient processing route over its combustion in recovery boilers, a substantial process efficiency improvement and operating costs reduction must be targeted in future research. Background and Objectives: Sulfur compounds found in black liquor partly turn into hydrogen sulfide during gasification and exit the gasifier in the syngas. Their efficient recovery in their sulfidic form to the pulping process is of utmost importance. Current studies focus on black liquor gasifier syngas desulfurization only. Materials and Methods: A mathematical model of two H2S absorption units from a 66.7 tDS/h (1600 tons dry solids per day) black liquor gasification process to 20 ppm H2S content in cleaned syngas using either white liquor plus NaOH or N-methyldiethanolamine (MDEA) was created using the Aspen Plus simulation software. Results: The results show that CO2 co-absorption significantly increases the lime kiln load: +20% in the MDEA alternative and +100% in the other one. The MDEA alternative requires almost the same investment costs but by around USD 9.7 million (>50%) lower annual operating costs compared to the other one. Economic evaluation was based on the assumed discount rate of 5% and on the expected plant operation time of 25 years. The estimated total investment cost of the whole plant is around USD 170 million for both alternatives. The whole plant including this alternative exhibits a positive net present value (over USD 19 million), an internal rate of return of 5% and a profitability index of 1.12, whereas that with the other alternative is economically infeasible. Conclusions: The MDEA-based syngas cleaning technology represents a more efficient and economically feasible option of sulfur recovery. A major drawback of both modeled syngas cleaning technologies is that their estimated annual operating costs significantly reduce the expected profit margin of gasification over the traditional black liquor combustion in a recovery boiler. Syngas cleaning and sulfur recovery have to be further optimized to reach a significant cut down in operational costs to improve the economic feasibility of black liquor gasification.

ACS Style

Michal Hruška; Miroslav Variny; Juma Haydary; Ján Janošovský. Sulfur Recovery from Syngas in Pulp Mills with Integrated Black Liquor Gasification. Forests 2020, 11, 1173 .

AMA Style

Michal Hruška, Miroslav Variny, Juma Haydary, Ján Janošovský. Sulfur Recovery from Syngas in Pulp Mills with Integrated Black Liquor Gasification. Forests. 2020; 11 (11):1173.

Chicago/Turabian Style

Michal Hruška; Miroslav Variny; Juma Haydary; Ján Janošovský. 2020. "Sulfur Recovery from Syngas in Pulp Mills with Integrated Black Liquor Gasification." Forests 11, no. 11: 1173.

Journal article
Published: 17 August 2020 in Sustainability
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The composition of gas produced by the gasification of refuse-derived fuel (RDF) can be affected by the content of individual components of RDF and their mutual interactions. In this work, plastics, paper, wood, textile and RDF were gasified in a two-stage gasification system and the obtained tar yields and product gas quality were compared. The two-stage reactor consisted of an air-blown gasifier and a catalytic reactor filled with carbonized tire pyrolysis char as the tar-cracking catalyst. Tire pyrolysis char is a promising alternative to expensive catalysts. The impact of temperature and catalyst amount on the tar yield and gas composition was investigated. Theoretical oxygen demand for all material classes was calculated and its effect on gas composition and tar yield is discussed. The results indicate that the gasification of plastics produces the highest amount of tar and hydrocarbon gases, while the CO2 content of the product gas remains the lowest compared to all other materials. On the other hand, the paper fraction produced hydrogen-rich gas with low tar content. The gasification of RDF at 700 °C provided the lowest tar yield compared to all other materials, indicating positive synergic effects of lignocellulosic biomass and plastics in tar reduction. The significance of these interactions was suppressed at the highest temperature of 900 °C, as the thermal cracking of tar became dominant. For CO2 content, a negative synergic effect (higher CO2 concentration) was observed.

ACS Style

Patrik Šuhaj; Jakub Husár; Juma Haydary. Gasification of RDF and Its Components with Tire Pyrolysis Char as Tar-Cracking Catalyst. Sustainability 2020, 12, 6647 .

AMA Style

Patrik Šuhaj, Jakub Husár, Juma Haydary. Gasification of RDF and Its Components with Tire Pyrolysis Char as Tar-Cracking Catalyst. Sustainability. 2020; 12 (16):6647.

Chicago/Turabian Style

Patrik Šuhaj; Jakub Husár; Juma Haydary. 2020. "Gasification of RDF and Its Components with Tire Pyrolysis Char as Tar-Cracking Catalyst." Sustainability 12, no. 16: 6647.

Original article
Published: 17 April 2020 in Biomass Conversion and Biorefinery
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Residues from agriculture and forest maintenance (lignocellulosic waste biomass) create a huge source of renewable energy and valuable materials. Gasification of this waste provides combustible gases consisting mainly of H2, CO and CO2, which can be used as syngas feed for methanol synthesis after treatment. Oxygen, steam or their mixtures can be used as gasifying agents in the biomass to methanol process. One of the most important parameters with crucial effect on gas composition and reactor temperature is the gasifying agent to feed mass flow ratio. In this work, gasification process of two samples of mixed agricultural waste, gas treatment and synthesis of methanol from the syngas produced was designed and simulated in the Aspen Plus environment. Three different cases were investigated: (1) only oxygen as gasifying agent, (2) oxygen and steam as gasifying agents without steam recycling and (3) oxygen and steam as gasifying agents with steam recycling. Samples of mixed agricultural waste consisted of corn leaves and stalks, wheat straw, barley straw, sunflowers and wood chips were characterised by proximate, ultimate and calorimetric analysis. Oxygen and steam flows were optimised to achieve maximum theoretical yield of methanol while maintaining the gasifier temperature, equal to, at least 900 °C. The best methanol to biomass ratio (MBR) of 0.43 was reached for a sample with lower moisture and ash content when both oxygen and steam were used as gasifying agents. The optimal oxygen to biomass ratio (OBR) was 0.57, and the steam to biomass ratio (SBR) was 0.89.

ACS Style

J. Haydary; P. Šuhaj; J. Husár. Waste biomass to methanol–optimisation of gasification agent to feed ratio. Biomass Conversion and Biorefinery 2020, 11, 419 -428.

AMA Style

J. Haydary, P. Šuhaj, J. Husár. Waste biomass to methanol–optimisation of gasification agent to feed ratio. Biomass Conversion and Biorefinery. 2020; 11 (2):419-428.

Chicago/Turabian Style

J. Haydary; P. Šuhaj; J. Husár. 2020. "Waste biomass to methanol–optimisation of gasification agent to feed ratio." Biomass Conversion and Biorefinery 11, no. 2: 419-428.

Original paper
Published: 19 November 2019 in Chemical Papers
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Pine needles are the waste of pine forest and produced in a substantial amount every year during the fall. If not extracted from forest bed, they cause a widespread forest fire. In this study, pine needles were converted to char at different temperatures using a screw type pyrolyzer with an aim to find out the effect of thermal stress on the properties of chars and their intended end uses. The chars were evaluated for intrinsic physico-chemical transformations in comparison with the raw pine needles. Differences between chars produced in three temperatures and the raw biomass were studied by thermogravimetric analysis. It was found that the char produced at higher temperature showed a superior profile of apparent activation energy as compared with the char from low temperature. Coats–Redfern kinetics was used to compare the activation energies of chars and raw biomass, which showed that the char obtained from higher temperature had better thermal stability. From this study it can be concluded that chars produced at low temperatures in the screw reactor are useful as source of fuel, whereas the char of higher temperature is suitable for soil application and preparation of activated char.

ACS Style

Sandip Mandal; Juma Haydary; Sandip Gangil; Jakub Husar; P. C. Jena; T. K. Bhattacharya. Inferences from thermogravimetric analysis of pine needles and its chars from a pilot-scale screw reactor. Chemical Papers 2019, 74, 689 -698.

AMA Style

Sandip Mandal, Juma Haydary, Sandip Gangil, Jakub Husar, P. C. Jena, T. K. Bhattacharya. Inferences from thermogravimetric analysis of pine needles and its chars from a pilot-scale screw reactor. Chemical Papers. 2019; 74 (2):689-698.

Chicago/Turabian Style

Sandip Mandal; Juma Haydary; Sandip Gangil; Jakub Husar; P. C. Jena; T. K. Bhattacharya. 2019. "Inferences from thermogravimetric analysis of pine needles and its chars from a pilot-scale screw reactor." Chemical Papers 74, no. 2: 689-698.

Journal article
Published: 27 October 2019 in Catalysts
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Municipal solid waste constitutes one of the major challenges and concerns of our society. Disposal of waste material is potentially dangerous, harming both environment and mankind. In order to diminish negative effects of municipal solid waste, its thermal decomposition to valuable chemicals has been studied. The principal draw-back of thermal processes used for solid waste utilization as raw material is tar formation. In this study, low-cost catalysts of different origin were tested in the decomposition of a model component of tar originating from waste material pyrolysis/gasification. p-Xylene was selected as the model compound found in biomass decomposition products. Its decomposition was carried out in the presence of either tire pyrolysis char- or clay minerals-based catalysts. Tar-cracking activities of both catalyst types at varying experimental conditions were compared and related to the catalysts physical-chemical properties. In experiments, either empty reactor or reactor filled with 10 g of the catalyst was used; p-xylene mass flow was set to 2.58 g h−1 (50 μL min−1, room temperature), and decomposition temperature ranging from 750 °C to 850 °C was applied. Moreover, evolution of the output variables, p-xylene conversion and hydrogen content in the gas phase, with the reaction time was investigated. Catalysts’ properties were assessed based on nitrogen adsorption isotherms, thermogravimetric and elemental composition analyses. Amounts and composition of p-xylene catalytic decomposition products were evaluated using GC analysis of both gaseous phase and condensable products. Results showed the superiority of tire pyrolysis char catalyst over that based on clay minerals.

ACS Style

Pavol Steltenpohl; Jakub Husár; Patrik Šuhaj; Juma Haydary. Performance of Catalysts of Different Nature in Model Tar Component Decomposition. Catalysts 2019, 9, 894 .

AMA Style

Pavol Steltenpohl, Jakub Husár, Patrik Šuhaj, Juma Haydary. Performance of Catalysts of Different Nature in Model Tar Component Decomposition. Catalysts. 2019; 9 (11):894.

Chicago/Turabian Style

Pavol Steltenpohl; Jakub Husár; Patrik Šuhaj; Juma Haydary. 2019. "Performance of Catalysts of Different Nature in Model Tar Component Decomposition." Catalysts 9, no. 11: 894.

Original paper
Published: 22 April 2019 in Chemical Papers
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Municipal solid waste (MSW) disposed in landfills is a serious environmental hazard and waste of potential source of reusable resources and energy as only a small portion of MSW is incinerated. Pyrolysis and gasification of MSW is an alternative to commercial combustion for the recovery of valuable chemicals and production of heat and electricity. Tar formation is a serious problem in the gasification process. Tar content in the product gas has to be decreased to a certain level required by the downstream production line. This can be achieved by the application of a suitable catalyst. However, commercial catalysts are expensive, prone to fast deactivation and sintering. Char from waste tire pyrolysis is a suitable catalyst for tar decomposition as it contains a significant amount of metals and has relatively large specific surface area. The advantage of this catalyst is its low price and no need for its regeneration as it can be simply combusted after losing its activity. In this work, catalysts prepared from tire pyrolysis char were activated at three different temperatures. The impact of activation temperature on the properties of prepared catalysts was analyzed. Tar cracking activity of the prepared catalysts was tested in a continuous tubular reactor and toluene was used as a model tar compound. Char activated at 900 °C achieved the highest toluene conversion and the lowest tar yield, so it was selected for application in batch gasification of refuse-derived fuel (RDF). During RDF gasification, the presence of a selected catalyst in the secondary reactor led to a decrease in the total amount of produced tar by 92.3% compared to non-catalytic (thermal) decomposition.

ACS Style

Jakub Husár; Juma Haydary; Patrik Šuhaj; Pavol Steltenpohl. Potential of tire pyrolysis char as tar-cracking catalyst in solid waste and biomass gasification. Chemical Papers 2019, 73, 2091 -2101.

AMA Style

Jakub Husár, Juma Haydary, Patrik Šuhaj, Pavol Steltenpohl. Potential of tire pyrolysis char as tar-cracking catalyst in solid waste and biomass gasification. Chemical Papers. 2019; 73 (8):2091-2101.

Chicago/Turabian Style

Jakub Husár; Juma Haydary; Patrik Šuhaj; Pavol Steltenpohl. 2019. "Potential of tire pyrolysis char as tar-cracking catalyst in solid waste and biomass gasification." Chemical Papers 73, no. 8: 2091-2101.

Journal article
Published: 01 April 2019 in Acta Chimica Slovaca
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An energy independent active indirect solar drying system for the study of food products drying at specific climate conditions was developed and tested. As a model material, sliced tomato was selected because of its short shelf live, high humidity and potential to be a high value dried product. Indirect solar dryer enabled complete protection of the dried material against sunlight, birds, insects, rain and dust during the drying process. The solar dryer system design includes a rectangular section (1000 × 600 × 400) mm chamber and a flat solar collector (1500 × 600 × 100) mm with the surface area of 0.9 m2. Air flow was induced by a fan installed at the inlet of the collector and powered by a photovoltaic solar panel and a battery system. Temperature and humidity of air were monitored at the collector inlet, collector outlet and the drying chamber outlet. The key element of the collector is a 10.5 m long rectangular section aluminum pipe (55 × 35) mm coated with an absorption layer. The maximum dryer capacity is around 3 kg of wet material (sliced tomato) per batch. Average air temperature increase in the collector was measured to be 30 °C during the winter season. Air relative humidity decreased from 21 % to 15 % after passing through the collector. The moisture of tomato slices decreased from the initial value of 92 % down to 22 % during the time of the experiment (30 h). Quality of tomatoes dried using the designed solar dryer differed significantly in color as well as in texture from those dried by the commonly used methods, like an open sun drying system. Equilibrium moisture content of the product was reached after 30 h in December when the maximum outside temperature was 17.6 °C. The tomato mass decreased from 333 g to 33.15 g; the mass loss being approximately 90 %. The heated air temperature and humidity at the dryer inlet and outlet were influenced by the change of the ambient temperature and humidity during the day. Variation of the drying rate with the change of the ambient temperature and humidity was observed. During summer, when the sun radiation increases, the drying time for sliced tomato with 9 mm thickness decreased from 25 h to 15 h. The sample thickness also has an impact on the drying process. When the sample thickness increased from 9 mm to 12 mm, the drying time increased from 15 h to 20 h of active device time.

ACS Style

Abdul Wasim Noori; Mohammad Jafar Royen; Juma Haydary. An active indirect solar system for food products drying. Acta Chimica Slovaca 2019, 12, 142 -149.

AMA Style

Abdul Wasim Noori, Mohammad Jafar Royen, Juma Haydary. An active indirect solar system for food products drying. Acta Chimica Slovaca. 2019; 12 (1):142-149.

Chicago/Turabian Style

Abdul Wasim Noori; Mohammad Jafar Royen; Juma Haydary. 2019. "An active indirect solar system for food products drying." Acta Chimica Slovaca 12, no. 1: 142-149.

Journal article
Published: 01 February 2019 in Chinese Journal of Chemical Engineering
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ACS Style

Eduard Manek; Juma Haydary. Investigation of the liquid recycle in the reactor cascade of an industrial scale ebullated bed hydrocracking unit. Chinese Journal of Chemical Engineering 2019, 27, 298 -304.

AMA Style

Eduard Manek, Juma Haydary. Investigation of the liquid recycle in the reactor cascade of an industrial scale ebullated bed hydrocracking unit. Chinese Journal of Chemical Engineering. 2019; 27 (2):298-304.

Chicago/Turabian Style

Eduard Manek; Juma Haydary. 2019. "Investigation of the liquid recycle in the reactor cascade of an industrial scale ebullated bed hydrocracking unit." Chinese Journal of Chemical Engineering 27, no. 2: 298-304.

Journal article
Published: 13 December 2018 in Waste Management
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Municipal solid waste (MSW) disposal is a serious environmental issue requiring immediate solution and good waste management strategy. Mechanical-biological treatment (MBT) plants offer the opportunity to reduce the amount of MSW that is, otherwise, disposed of in landfills. Up to 40% of MSW is converted to waste fuel, also called refuse-derived fuel (RDF). Gasification is a promising alternative of RDF processing. It can be defined as high temperature treatment of the feedstock with lower than stoichiometric amount of oxygen resulting mainly in a gaseous product (syngas). High hydrogen content, specific ratio of H2/CO, and low tar content are important parameters of syngas for its application in both energy production and chemical synthesis. Reduction of tar content in syngas can be achieved by catalytic tar cracking. In this work, a catalyst prepared from natural clay was characterised by thermogravimetric, specific surface area, X-ray diffraction, X-ray fluorescence and scanning electron microscopy (SEM) analyses. Catalyst activity was tested in two reactions, namely in decomposition of model tar constituent, p-xylene, and in cracking of tar produced in RDF gasification experiments. Influence of the reaction temperature and the amount of catalyst on the p-xylene conversion and products’ distribution was studied. The results proved high catalytic activity of the prepared catalyst in the decomposition of p-xylene. Coupled RDF pyrolysis and the produced volatiles gasification experiments were carried out in a two-stage laboratory scale reactor using a bed of tar cracking catalyst in the second stage. Tar decomposition experiments were carried out at the reactor temperatures of 700–850 °C applying different amounts of catalyst (0.75 g, 1 g, 1.25 g, 1.5 g, 2 g and 4 g) per 1 g of pyrolised RDF. Results indicate that the presence of catalyst had significant effect on both tar cracking efficiency and gas composition. Loss of the catalyst specific surface area was observed when the experiments were carried out at temperatures exceeding 800 °C.

ACS Style

Patrik Šuhaj; Juma Haydary; Jakub Husár; Pavol Steltenpohl; Ivan Šupa. Catalytic gasification of refuse-derived fuel in a two-stage laboratory scale pyrolysis/gasification unit with catalyst based on clay minerals. Waste Management 2018, 85, 1 -10.

AMA Style

Patrik Šuhaj, Juma Haydary, Jakub Husár, Pavol Steltenpohl, Ivan Šupa. Catalytic gasification of refuse-derived fuel in a two-stage laboratory scale pyrolysis/gasification unit with catalyst based on clay minerals. Waste Management. 2018; 85 ():1-10.

Chicago/Turabian Style

Patrik Šuhaj; Juma Haydary; Jakub Husár; Pavol Steltenpohl; Ivan Šupa. 2018. "Catalytic gasification of refuse-derived fuel in a two-stage laboratory scale pyrolysis/gasification unit with catalyst based on clay minerals." Waste Management 85, no. : 1-10.

Journal article
Published: 01 October 2018 in Acta Chimica Slovaca
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In this work, drying of tomato slices was studied in a laboratory scale batch dryer working at conditions specific for geographical locations with low ambient pressure and low relative humidity of air. Tomato is a perishable farm product with high moisture content. Despite their high value, tomatoes are subjected to wastage and spoilage during their seasonal period; to last longer after harvested, they need to be treated by drying. Drying is one of the most widely used methods of tomato preserving for a longer period of time. This study involves experimental work on tomatoes drying in a tray laboratory batch dryer with the dimensions of (490 × 330 × 310) mm, a load cell-force sensor (range: 0–5 kg), fan (speed: 0–2500 rpm), air flow sensor (0–150 l/min) and a temperature and humidity monitoring system. This study was aimed at the development of a suitable drying method for the production of dehydrated agricultural products under specific air properties and climate conditions such as low ambient pressure and low relative humidity. During the experiment, the average ambient pressure was 82 kPa, and the average relative humidity of air was 20 %. Drying characteristics of tomato slices were determined at three temperature levels, namely: 50 °C, 60 °C and 70 °C,and three air flow rates: 30 l/s, 40 l/s and 50 l/s, for each temperature level. In this study, the effect of temperature, air flow rate, and ambient conditions on the drying rate of tomato slices were studied. The results indicate that during the experiments, tomatoes were dried to the final moisture content of 32.2 % from 92 %. Drying time at 50 °C, 60 °C and 70°C, and air flow of 30 l/s was 17.80 h, 15.80 h, and 14.08 h, respectively. For the air flow rate of 40 l/s, the drying time was 15.0 h, 12.9 h and 11.7 h and for the air flow rate of 50 l/s, the drying time of tomato slices was 14.0 h, 11.6 h and 10.2 h, respectively.

ACS Style

Mohammad Jafar Royen; Abdul Wasim Noori; Juma Haydary. Batch drying of sliced tomatoes at specific ambient conditions. Acta Chimica Slovaca 2018, 11, 134 -140.

AMA Style

Mohammad Jafar Royen, Abdul Wasim Noori, Juma Haydary. Batch drying of sliced tomatoes at specific ambient conditions. Acta Chimica Slovaca. 2018; 11 (2):134-140.

Chicago/Turabian Style

Mohammad Jafar Royen; Abdul Wasim Noori; Juma Haydary. 2018. "Batch drying of sliced tomatoes at specific ambient conditions." Acta Chimica Slovaca 11, no. 2: 134-140.

Original paper
Published: 25 June 2018 in Waste and Biomass Valorization
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The purpose of this study was to optimize the pyrolysis conditions to obtain maximum bio-oil yield from pine needles using a screw pyrolyzer for utilizing this abundantly available ligno-cellulosic biomass from pine forest as an alternate source of fuel. Pyrolysis was conducted in a pilot scale single screw reactor. Process parameters such as pyrolysis temperature, biomass particle size, solid residence time and gas flow rate were optimized by employing Taguchi’s L9 Orthogonal Array. Chemical characterization of bio-oil was conducted using gas chromatographic/mass spectroscopy (GC/MS) analysis. Fuel properties of bio-oil and biochar were determined using ASTM standard methods. Composition of product gas was determined by gas chromatography and higher heating value (HHV) was calculated theoretically. Results revealed that bio-oil yield was primarily influenced by pyrolysis temperature and biomass particle size. The optimum conditions for maximum bio-oil yield were—pyrolysis temperature of 500 °C, particle size of 1.25–2.0 mm, solid residence time of 15 min and N2 gas flow rate of 30 l h− 1(Gas flow velocity ∼ 0.33 m min−1). A maximum bio-oil yield of 28.98% was achieved at optimum conditions. Optimized conditions found in this experiment can be employed to continuous pyrolysis of pine needles for production of higher grade energy products like bio-oil, biochar and product gas through screw reactor.

ACS Style

Sandip Mandal; Juma Haydary; T. K. Bhattacharya; H. R. Tanna; Jakub Husár; Ales Haz. Valorization of Pine Needles by Thermal Conversion to Solid, Liquid and Gaseous Fuels in a Screw Reactor. Waste and Biomass Valorization 2018, 10, 3587 -3599.

AMA Style

Sandip Mandal, Juma Haydary, T. K. Bhattacharya, H. R. Tanna, Jakub Husár, Ales Haz. Valorization of Pine Needles by Thermal Conversion to Solid, Liquid and Gaseous Fuels in a Screw Reactor. Waste and Biomass Valorization. 2018; 10 (12):3587-3599.

Chicago/Turabian Style

Sandip Mandal; Juma Haydary; T. K. Bhattacharya; H. R. Tanna; Jakub Husár; Ales Haz. 2018. "Valorization of Pine Needles by Thermal Conversion to Solid, Liquid and Gaseous Fuels in a Screw Reactor." Waste and Biomass Valorization 10, no. 12: 3587-3599.

Journal article
Published: 26 October 2017 in Acta Chimica Slovaca
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Approximately 1 300 Gt of municipal solid waste (MSW) are produced worldwide every year. Most of it is disposed of in landfills, which is very hazardous for the environment. Up to 10 % of produced MSW are incinerated. However, incineration is not very effective and requires specific conditions for preventing emissions. Gasification and pyrolysis are more effective processes which can be used not only for heat and electricity generation but also for fuel and valuable chemicals production. MSW can be transformed into refuse-derived fuel (RDF) which has higher heat of combustion. Synthesis gas produced by RDF gasification can be utilised in methanol production. Methanol is a very lucrative chemical which can be used as renewable liquid fuel or as a reagent in organic syntheses. Gasifier design and process optimisation can be done using a reliable mathematical model. A good model can significantly decrease the number of experiments necessary for the gasification process design. In this work, equilibrium model for RDF gasification was designed in Aspen Plus environment and the flow of oxygen and steam as gasification agents were optimised to achieve the highest theoretical methanol yield. Impact of the recycle of unreacted steam and produced tar on the methanol yield was evaluated. The highest theoretical methanol yield (0.629 kgMEOH/kgRDF) was achieved when the steam and tar recycle were switched on, the ratio between oxygen and RDF feed was 0.423 kg/kg and that between the steam and RDF feed was 0.606 kg/kg. In this case, fresh steam represented only 12 % of the total steam fed to the reactor, the rest consisted of recycled steam. Optimal gasifier temperature was 900 °C.

ACS Style

Patrik Šuhaj; Jakub Husár; Juma Haydary. Modelling of syngas production from municipal solid waste (MSW) for methanol synthesis. Acta Chimica Slovaca 2017, 10, 107 -114.

AMA Style

Patrik Šuhaj, Jakub Husár, Juma Haydary. Modelling of syngas production from municipal solid waste (MSW) for methanol synthesis. Acta Chimica Slovaca. 2017; 10 (2):107-114.

Chicago/Turabian Style

Patrik Šuhaj; Jakub Husár; Juma Haydary. 2017. "Modelling of syngas production from municipal solid waste (MSW) for methanol synthesis." Acta Chimica Slovaca 10, no. 2: 107-114.

Journal article
Published: 05 October 2017 in Chemical Papers
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ACS Style

Sandip Mandal; T. K. Bhattacharya; A. K. Verma; Juma Haydary. Optimization of process parameters for bio-oil synthesis from pine needles (Pinus roxburghii) using response surface methodology. Chemical Papers 2017, 72, 603 -616.

AMA Style

Sandip Mandal, T. K. Bhattacharya, A. K. Verma, Juma Haydary. Optimization of process parameters for bio-oil synthesis from pine needles (Pinus roxburghii) using response surface methodology. Chemical Papers. 2017; 72 (3):603-616.

Chicago/Turabian Style

Sandip Mandal; T. K. Bhattacharya; A. K. Verma; Juma Haydary. 2017. "Optimization of process parameters for bio-oil synthesis from pine needles (Pinus roxburghii) using response surface methodology." Chemical Papers 72, no. 3: 603-616.

Journal article
Published: 01 May 2017 in Fuel Processing Technology
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ACS Style

Eduard Manek; Juma Haydary. Hydrocracking of vacuum residue with solid and dispersed phase catalyst: Modeling of sediment formation and hydrodesulfurization. Fuel Processing Technology 2017, 159, 320 -327.

AMA Style

Eduard Manek, Juma Haydary. Hydrocracking of vacuum residue with solid and dispersed phase catalyst: Modeling of sediment formation and hydrodesulfurization. Fuel Processing Technology. 2017; 159 ():320-327.

Chicago/Turabian Style

Eduard Manek; Juma Haydary. 2017. "Hydrocracking of vacuum residue with solid and dispersed phase catalyst: Modeling of sediment formation and hydrodesulfurization." Fuel Processing Technology 159, no. : 320-327.

Journal article
Published: 01 March 2016 in GeoScience Engineering
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In this work, the gasification of a fraction of municipal solid waste, MSW, generally separated from inorganic materials and biodegradable components, the so-called refuse-derived fuel (RDF), was studied using material characterisation methods, and the modelling of an industrial scale process was presented. The composition of RDF was determined by the separation of a representative sample into its basic components (paper, foils, hard plastics, textiles). All RDF components as well as a representative mixed sample of the RDF were studied using a thermogravimetric analysis (TGA), elemental analysis and bomb calorimetry to determine their proximate and elemental compositions, and a higher heating value. An industrial scale gasification process was studied by mathematical modelling and computer simulations. All techniques, gasification with air, gasification with oxygen, and gasification with both oxygen and steam were investigated under different conditions. The RDF conversion of 100 % was achieved by the gasification with air at the air to RDF mass ratio of 3.2. The gas heating value was 4.4 MJ/Nm3. The gasification of RDF using oxygen enables the production of gas with the heating value of around 10 MJ/Nm3 at the oxygen to RDF mass ratio of 0.65. By increasing the steam to the RDF mass ratio, the contents of H2 and CO2 increased, while the content of CO, reactor temperature and the gas heating value decreased.

ACS Style

Juma Haydary. Gasification of Refuse-Derived Fuel (RDF). GeoScience Engineering 2016, 62, 37 -44.

AMA Style

Juma Haydary. Gasification of Refuse-Derived Fuel (RDF). GeoScience Engineering. 2016; 62 (1):37-44.

Chicago/Turabian Style

Juma Haydary. 2016. "Gasification of Refuse-Derived Fuel (RDF)." GeoScience Engineering 62, no. 1: 37-44.

Journal article
Published: 01 March 2016 in Journal of Environmental Chemical Engineering
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ACS Style

J. Haydary; D. Susa; V. Gelinger; F. Čacho. Pyrolysis of automobile shredder residue in a laboratory scale screw type reactor. Journal of Environmental Chemical Engineering 2016, 4, 965 -972.

AMA Style

J. Haydary, D. Susa, V. Gelinger, F. Čacho. Pyrolysis of automobile shredder residue in a laboratory scale screw type reactor. Journal of Environmental Chemical Engineering. 2016; 4 (1):965-972.

Chicago/Turabian Style

J. Haydary; D. Susa; V. Gelinger; F. Čacho. 2016. "Pyrolysis of automobile shredder residue in a laboratory scale screw type reactor." Journal of Environmental Chemical Engineering 4, no. 1: 965-972.

Conference paper
Published: 30 May 2014 in Springer Proceedings in Physics
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Three types of wooden biomass were characterized by calorimetric measurements, proximate and elemental analysis, thermogravimetry, kinetics of thermal decomposition and gas composition. Using the Aspen steady state simulation, a plant with the processing capacity of 18 ton/h of biomass was modelled based on the experimental data obtained under laboratory conditions. The gasification process has been modelled in two steps. The first step of the model describes the thermal decomposition of the biomass based on a kinetic model and in the second step, the equilibrium composition of syngas is calculated by the Gibbs free energy of the expected components. The computer model of the plant besides the reactor model includes also a simulation of other plant facilities such as: feed drying employing the energy from the process, ash and tar separation, gas-steam cycle, and hot water production heat exchangers. The effect of the steam to air ratio on the conversion, syngas composition, and reactor temperature was analyzed. Employment of oxygen and air for partial combustion was compared. The designed computer model using all Aspen simulation facilities can be applied to study different aspects of biomass gasification in a Combined Heat and Power plant.

ACS Style

Juma Haydary; Ľudovít Jelemenský. Design of Biomass Gasification and Combined Heat and Power Plant Based on Laboratory Experiments. Springer Proceedings in Physics 2014, 171 -178.

AMA Style

Juma Haydary, Ľudovít Jelemenský. Design of Biomass Gasification and Combined Heat and Power Plant Based on Laboratory Experiments. Springer Proceedings in Physics. 2014; ():171-178.

Chicago/Turabian Style

Juma Haydary; Ľudovít Jelemenský. 2014. "Design of Biomass Gasification and Combined Heat and Power Plant Based on Laboratory Experiments." Springer Proceedings in Physics , no. : 171-178.