RESEARCH PAPERS
Chemical Engineering, Gas Cleaning, Bag Filter, Bio-Oil, CFBC, Coal, Energy, Renewable Energy, Process Simulation
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects
41 Fluidized bed fast pyrolysis of corn stover: Effects of fluidizing gas flow rate and composition
Najaf Ali, Muhammad Ashraf, Khurram Shahzad, Mahmood Saleem, Arshad Chughtai
https://www.tandfonline.com/doi/abs/10.1080/15567036.2019.1694105
ABSTRACT
Fast pyrolysis of corn stover was carried out in a pilot scale fluidized bed reactor in nitrogen atmosphere. The effects of varying gas flow rates at optimum reaction temperature of about 500ºC and feed size of < 1.0 mm on yield and composition of bio-oil, char and gas were investigated. The results for three runs with flow rate of gas of 45, 80 and 70 L/min, respectively, were obtained. The distribution of pyrolysis products was calculated gravimetrically by mass balance and corrected with optimization mass model using proximate and ultimate analysis of feedstock and pyrolysis products. The maximum yield of bio-oil (52 wt%) was obtained in run 3 with flow rate of gas of 70 L/min having heating value of 21.20 MJ/kg. GC-MS analysis identified the major chemical compounds present in the bio-oil which were levoglucosan, hydroxyl acetaldehyde, acetol, acetic acid, phenols, 2-methyl-2-cylopenten-1-one, guaiacol, 2(5H)-furanone, fufuryl alcohol, p-cresol and 2-ethyl alcohol. The bio-oil produced from run 3 had higher amounts of aromatic hydrocarbons, non-methoxylated phenolics, levoglucosan and smaller amounts of acids. On the other hand, bio-oil obtained from TGRP experiments had low value of total acid number (57.73 mg of KOH/g) indicating less oxygenating compounds with greater heating value in the product.
International Journal of Energy Research
Hafiza Mamoona Khalid, Afshan Mujahid, Asif Ali, Asim Laeeq Khan, Mahmood Saleem, Rafael M Santos
https://onlinelibrary.wiley.com/doi/full/10.1155/2024/2107340
Abstract
The ever-escalating CO2 concentration in the atmosphere calls for accelerated development and deployment of carbon capture processes to reduce emissions. Mixed matrix membranes (MMMs), which are fabricated by incorporating the beneficial properties of highly selective inorganic fillers into a polymer matrix, have exhibited significant progress and the ability to enhance the performance of a membrane for gas separation. In this research, an amine-based ionic liquid (IL) [APTMS][AC] was prepared, which has greater CO2 affinity and greater solubility due to its amine moiety. The metal–organic framework (MOF) UiO-66 with a multidimensional crystalline structure was used as a filler due to its appropriate porosity and tunable properties, and it was functionalized with NH2. MOFs were further modified with an IL to prepare UiO-66@IL and UiO-66-NH2@IL, and MMMs incorporating each MOF were fabricated with the polymer Pebax-1657. All the prepared membranes and MOFs were characterized to predict their separation efficiency. Several characterization techniques, namely, FTIR spectroscopy, XRD, and SEM, were used to successfully synthesize UiO-66@IL and UiO-66-NH2@IL composites and confirmed proper dispersion and excellent polymer‒filler compatibility at filler loadings ranging from 0 to 30 wt.%. The separation performances were investigated, and the results showed that the incorporation of RTIL with the highly crystalline structure and large surface area of UiO-66 enhanced the separation efficiency of the membrane. The permeability of CO2 for all fabricated membranes continuously increased with increasing filler concentration, wherein the permeability was comparatively high for the UiO-66-NH2 MMMs. The CO2/CH4 selectivity improved by 35%, 54%, and 60%, respectively, for UiO-66@IL, UiO-66-NH2, and UiO-66-NH2@IL MMMs compared to simple UiO-66 for CO2/CH4 and by 28%, 36%, and 63%, respectively, for CO2/N2, with an increase in filler loading in the MMMs.
39 A comparative study of thermal and combustion kinetics for raw and bio-chars of eucalyptus wood and bark
Iqra Aziz, Zaeem Bin Babar,Rizwan Haider,Mahmood Saleem,Shahid Munir&Hamed Sattar
Pages 3313-3329 | Received 25 Feb 2021, Accepted 30 Mar 2022, Published online: 14 Apr 2022
ABSTRACT
This study investigates thermal and combustion kinetics of raw and bio-char samples of eucalyptus wood and bark. Raw samples of eucalyptus wood and bark were subjected to pyrolysis at temperatures of 300, 350, 400, and 450°C. The maximum mass yield was obtained at 350°C for both bio-char samples of wood and bark. Gross calorific value, proximate, ultimate, and chemical analyses of the raw and their derived bio-chars showed high energy yield of bio-chars as compared to raw samples. Thermal analysis of raw and their respective bio-chars was also studied using thermogravimetric analysis in air at heating rates of 25, 35, and 45°C min−1. Raw wood and bark in comparison to their bio-chars showed delayed ignition that resulted in increase of ignition, peak, and burn-out temperatures. Mean reactivity of raw and bio-char samples was obtained using Ghetti model that showed higher reactivity of raw samples than bio-chars. Kinetic parameters including activation energy and order of reaction were found using Arrhenius model. For different heating rates, activation energies lied in the range of 61–108 kJ mol−1 (wood) and 42–79 kJ mol−1 (bark). Higher carbon contents in the bio-char samples resulted in higher activation energies than raw samples. This increasing carbon contents trend also furnished increase activation energies of bio-chars.
https://www.tandfonline.com/doi/full/10.1080/15567036.2022.2062490?scroll=top&needAccess=true
International Journal of Chemical Engineering
38 Dry Reforming of Methane with Mesoporous Ni/ZrO2 Catalyst
Subhan Azeem, Rabya Aslam, Mahmood Saleem
https://onlinelibrary.wiley.com/doi/full/10.1155/2022/3139696
Abstract
Dry reforming of methane has exhibited significant environmental benefits as it utilizes two major greenhouse gases (CO2 and CH4) to produce synthesis gas, a major building block for hydrocarbons. This process has gained industrial attention as catalyst deactivation due to coke deposition being a major hindrance. The present study focuses on the dry reforming of methane over Ni-supported mesoporous zirconia support. Ni metal was loaded over in-house synthesized mesoporous zirconia within the 0–15 wt% range using the wet impregnation method. The physicochemical properties of the synthesized catalysts were studied using various characterization techniques, namely, XRD, SEM, FTIR, TGA, and N2 adsorption-desorption techniques. The activity of all the catalysts was evaluated at 750°C and gas hourly space velocity (GHSV) of 72000 ml/h/gcat for 9 hours (540 min). The deactivation factor indicating a loss in conversion with time is reported for each catalyst. 10 wt% Ni/ZrO2 showed the highest feed conversion of about 68.8% for methane and 70.2% for carbon dioxide and the highest stability (15.1% deactivation factor and 21% weight loss) for dry reforming of methane to synthesis gas.
International Journal of Energy Research
37 Biogenic methane generation from Vietnamese coal after pretreatment with hydrogen peroxide
Zaixing Huang, Michael A Urynowicz, Rizwan Haider, Hamed Sattar, Mahmood Saleem, Lan Hoang, Ngoc Tran Han, Kim Anh To, Le Quoc Hung, Muhammad Ishtiaq Ali, Honggunag Guo, Huan He, Fang‐Jing Liu
https://onlinelibrary.wiley.com/doi/abs/10.1002/er.6985
ABSTRACT
The application of coal as a methanogenic substrate is limited due to its recalcitrant nature, thus, requiring pretreatment for increasing bioavailability of coal. This paper describes the pretreatment of Vietnamese coal from the Red River Basin. The coal sample was treated with 3% (vol/vol) hydrogen peroxide, which resulted in 45.4% (weight %) solubilization of coal and release of various organics into the liquid phase. This dissolved fraction was analyzed for total dissolved organic carbon, Fourier transform infrared spectroscopy, high-performance size exclusion chromatography, and high-performance liquid chromatography. The detailed analytical investigations revealed the presence of aliphatics and aromatics hydrocarbons in the liquid phase. Short-chain organic acids, including oxalic, citric, malic, malonic, formic, and acetic acids were also observed. The dissolved fraction was subjected to methanogenesis. Methane generation achieved the peak at 218.5 μmol/g coal after 500 days of incubation. The effect of the pretreatment process on inorganic matter of the residual coal samples was also assessed using inductively coupled plasma mass spectrometry. The pretreatment caused a reduction in metal content of the residual coal sample. The findings of the paper can be prospected as a feasibility study of methane production from Vietnamese coal after its pretreatment using hydrogen peroxide.
Energies
Saad Saeed, Mahmood Saleem, Abdullah Durrani, Junaid Haider, Muzaffar Riaz, Sana Saeed, Muhammad Abdul Qyyum, Abdul-Sattar Nizami, Mohammad Rehan, Moonyong Lee
Abstract
Pyrolysis behavior of ionic liquid (IL) pretreated coal and sugarcane bagasse (SCB) blends through thermogravimetric analysis (TGA) was studied. Three blends of coal and SCB having 3:1, 1:1, and 1:3 ratios by weight were treated with 1-ethyl-3-methylimidazolium chloride ([Emim][Cl]) at 150 °C for 3 h. Untreated and IL treated blends were then analyzed under pyrolytic conditions in a TGA at a constant ramp rate of 20 °C/min. Kinetic and thermodynamic parameters were evaluated using ten Coats-Redfern (CR) models to assess reaction mechanism. Results showed that the untreated blends followed a definite pattern and were proportional to the concentration of SCB in the blends. IL treated blends exhibited a higher average rate of degradation and total weight loss, indicating that IL had disrupted the cross-linking structure of coal and lignocellulosic structure of SCB. This will enhance the energy generation potential of biomass through thermochemical conversion processes. The lower activation energy (Ea) was calculated for IL treated blends, revealing facile thermal decomposition after IL treatment. Thermodynamic parameters, enthalpy change (ΔH), Gibbs free energy change (ΔG), and entropy change (ΔS), revealed that the pyrolysis reactions were endothermic. This study would help in designing optimized thermochemical conversion systems for energy generation.
Keywords:
sugarcane bagasse; ionic liquids; pretreatment; thermogravimetric analysis; co-pyrolysis; kinetic analysis
Fuel
Saad Saeed, Mahmood Saleem, Abdullah Durrani
Abstract
This paper aims to investigate the thermochemical behavior and synergistic effects of low-rank coal, and sugarcane bagasse (SCB) blends after pretreatment by trihexyltetradecylphosphonium chloride ([P66614] [Cl]). Three samples of coal and SCB blends, C75B25, C50B50, and C25B75, in ratios 3:1, 1:1, and 1:3 by weight, respectively, were prepared and pretreated with [P66614] [Cl] at 150 °C for 3 h. Hereafter, they were subjected to thermogravimetric analysis (TGA) under an inert atmosphere at a fixed heating rate of 20 °C. Thermal performance and synergistic effects were evaluated and compared by reactivity, kinetic, and thermodynamic analysis. Ten different models related to four reaction mechanisms were applied to evaluate kinetic and thermodynamic parameters. During pretreatment, [P66614] [Cl] was completely absorbed in blends and individual fuels. TGA results showed that IL treatment altered the thermal profiles of the blends at 350–500 °C. [P66614] [Cl] treatment caused an increase in total weight loss of 7.15%, 2.81%, and 1.62% for C75B25, C50B50, and C25B75, respectively. Peak temperatures for C75B25, C50B50, and C25B75 changed from 356, 365, and 374 °C to 472, 459, and 485 °C, respectively, after IL treatment, indicating thermal stability. The relative mean reactivity (Rm) for C75B25 increased (8.78 to 14.94%min−1°C−1), whereas for C50B50 and C25B75 (16.1 and 20.15%min−1°C−1 to 14.84 and 13.61%min−1°C−1) decreased after [P66614] [Cl] treatment, implying synergistic effects. Among the reaction models, R2 values in excess of 0.80 were obtained for all the samples, with activation energy of C75B25, C50B50, C25B75, C75B25 + [P66614] [Cl], C50B50 + [P66614] [Cl], and C25B75 + [P66614] [Cl] in the range of 12.48–51.17 kJ/mol, 12.53–46.07 kJ/mol, 10.85–45.40 kJ/mol, 8.11–35.50 kJ/mol, 6.9–33.59 kJ/mol, 6.65–41.32 kJ/mol, respectively. Entropy values suggested increased depolymerization of fuel structure due to IL treatment. Low synergy was detected in untreated as compared to IL treated blends. [P66614] [Cl] treatment seemed to have a more significant effect on samples having higher carbon content as compared to SCB. This study could be useful in modeling and designing co-thermochemical conversion processes for coal and SCB blends after low-cost [P66614] [Cl] pretreatment.
Fuel
Saad Saeed, Mahmood Saleem, Abdullah Khan Durrani
https://www.sciencedirect.com/science/article/pii/S0016236120309443
Abstract
This corrigendum corrects Table 4 and related discussion of the manuscript titled “Thermal performance analysis of low-grade coal pretreated by ionic liquids possessing imidazolium, ammonium, and phosphonium cations” [Fuel 271 (2020) 117655]. It was found that the sum of proximate analysis values in Table 4 exceeded 100% by a very small margin (0.27–0.59). The data was revisited, and corrections have been made. Since correlations were used to perform ultimate analysis and HHV values using proximate analysis data, these values have been corrected as well. The corrections do not affect the conclusions of the manuscript.
Journal of Molecular Liquids
33 Thermal performance analysis of sugarcane bagasse pretreated by ionic liquids
Saad Saeed, Mahmood Saleem, Abdullah Durrani
https://www.sciencedirect.com/science/article/pii/S0167732219368722
Abstract
This work investigated the pretreatment effect of four ionic liquids (ILs) on sugarcane bagasse (SCB) through reactivity, kinetic, and thermodynamic analysis. The ILs used in this study were 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]), 1-butyl-3-methylimidazolium methylsulfate ([Bmim][MeSO4]), Tris (2-hydroxyethyl) methylammonium methylsulfate ([MTEOA][MeSO4]), and trihexyltetradecylphosphonium chloride ([P66614] [Cl]). Pretreatment was carried out at 150 °C and 30 min, followed by thermal analysis of samples in a thermogravimetric analyzer (TGA). The activity parameters were obtained using TGA data. [P66614] [Cl] was completely absorbed in SCB, which strongly influenced the thermochemical behavior of [P66614] [Cl] treated sample. Results revealed that IL pretreatment greatly reduced ash content and increased the higher heating value (HHV) of SCB. Chemical composition analysis showed delignification of SCB by [Bmim][Cl], [Bmim][MeSO4] and [MTEOA][MeSO4]. However, [P66614] [Cl] increased lignin content indicating thermal stability. The obtained values of activation energy (Ea) for [Bmim][Cl], [Bmim][MeSO4], and [MTEOA][MeSO4] were much lower than that for untreated SCB, suggesting destruction of the lignocellulosic structure. Higher entropy change (ΔS) values after IL treatment implied higher disorder due to the breakage of SCB structure. The study demonstrated that the nature of cations and anions strongly influences the pretreatment potential of ILs for biomass undergoing thermochemical conversion processes.
Coatings
32 Theoretical Analysis of Roll-Over-Web Surface Thin Layer Coating
Tareq Manzoor, Muhammad Zafar, Shaukat Iqbal , Kashif Nazar , Muddassir Ali , Mahmood Saleem , Sanaullah Manzoor and Woo Young Kim
https://www.mdpi.com/2079-6412/10/7/691
Abstract
This study presents the theoretical investigation of a roll-over thin layer formation under the lubrication approximation theory. The set of differential equations derived by lubrication approximation is solved by the optimal homotopy asymptotic method (OHAM) to obtain precise expressions for pressure and velocity gradients. Critical quantities such as velocity, pressure gradient, and coating layer depth are numerically estimated. The impact of parameters affecting the coating and layer formation is revealed in detail. Results indicate that the transport properties of the higher-grade fluid play an essential role in regulating velocity, pressure, and the final coated region. Moreover, couple stress effects on the properties of fluid particles to be coated on roller-surface have also been studied.
Keywords:
roll-over-web coating; couple stress fluid; lubrication approximation theory; optimal homotopy asymptotic method (OHAM)
Fuel
Saad Saeed, Mahmood Saleem, Abdullah Khan Durrani
https://www.sciencedirect.com/science/article/pii/S0016236120306505
Abstract
This paper aims to investigate the impact of ionic liquid (ILs) pretreatment on low-grade coal for the thermochemical conversion process. Two imidazolium-based ILs, 1-butyl-3-methylimidazolium chloride [Bmim][Cl], and 1-ethyl-3-methylimidazolium chloride [Emim][Cl]; one ammonium-based IL, tributylmethylammonium chloride [N1444] [Cl]; and one phosphonium-based IL trihexyltetradecylphosphonium chloride [P66614] [Cl], were selected for this study. Reactivity, kinetic, and thermodynamic parameters were calculated via thermogravimetric analysis (TGA) conducted under N2 environment at a ramp rate of 20 °C/min. All four ILs increased the higher heating value (HHV) of coal. The IL treatment resulted in greater mass loss and enhanced reactivity of coal. The highest reactivity of 11.45%min−1°C−1 and pyrolysis factor (PF) of 23.28, nearly four and six times, respectively, higher than that of raw coal, were recorded for the [P66614] [Cl] treated sample. This could be attributed to the complete absorption of [P66614] [Cl] in coal and its high hydrogen bond basicity (HBB). Activation energies and pre-exponential factors were calculated using the model-fitting analysis with regression coefficient R2 in the range of 0.979–0.999. All ILs, except [P66614] [Cl], reduced the activation energy of coal, indicating degradation of coal structure. The higher activation energy in the case of [P66614] [Cl] suggests increase in thermal stability of coal. The results indicate that relatively low-cost phosphonium and ammonium-based ILs can be potential pretreatment agents for coal thermochemical conversion processes.
Asia‐Pacific Journal of Chemical Engineering
Naila Amin, Muhammad Suleman Tahir, Mehmood Saleem, Zakir Khan, Muhammad Aslam, Aqeel Ahmed Bazmi, Moinuddin Ghauri, Muhammad Sagir
https://onlinelibrary.wiley.com/doi/abs/10.1002/apj.2400
Abstract
Coal–water slurry (CWS) has been targeted as a promising fuel and an alternative to fuel oil. CWS has numerous advantages of low and convenient transportation and high solid content. Pakistan is going through a severe energy crisis and among the top 10 countries facing energy crises reported by the United Nations. Besides, Pakistan has become the top seventh country in coal reserves (i.e., 185 billion tones) after the discovery of huge lignite coal reserves in Thar, Sind province. Previous studies investigated the use of additives to enhance CWS properties at a low shear rate and its utilization accordingly. Particularly, the present work studied the high range of shear rate to improve the properties of CWS for transportation and combustion purposes. This study on the improvement in performance of rheology properties of CWS is conducted to improve the properties by cost-effective additives. The coal concentration varies from 20% to 60%, whereas runs were carried out with and without the cost-effective additives. The results demonstrated that the coal slurry showed shear-thinning property when viscosity was increased at high concentrations in the absence of additives. The addition of additive changed the rheological behavior from pseudoplastic to dilatant region. The presence of a high fraction of coal increased the apparent viscosity of CWS. The static stability test of all coal samples was performed using rod drop method at concentrations of 40% to 60%. The study found that stability was achieved earlier with a lower concentration of 40% as compared with higher concentrations of 50–60%. It is expected that this research would be helpful for the country facing adverse energy crises that badly affect the economy and other social aspects of human life.
Materials Express
Tareq Manzoor, Muhammad Zafar, Muddassir Ali, Mahmood Saleem, and Woo Young Kim
https://www.ingentaconnect.com/contentone/asp/me/2020/00000010/00000008/art00020
ABSTRACT
In this present study, the particulars of an experimental investigation on the effect of nickel addition on microstructural, strain recovery and strain absorption capacity of ternary (Cu–Al–Mn) shape memory alloys has been deliberated. Six dissimilar compositions with varying amounts of Ni in (Cu–Al–Mn) shape memory alloys have been synthesized and investigated to measure their potential for structural applications. Microstructural and detailed phase analysis has been studied. Additions of Ni have enhanced the tensile strength of these alloys. These compositional variations have influenced shape memory and damping properties in from of dissipated strain energy as well as the super elasticity of the alloys.
JOURNAL OF FACULTY OF ENGINEERING & TECHNOLOGY
28 HYDRODYNAMIC STUDY OF INDIGENOUS BIOMASS-SAND MIXTURES IN A COLD FLUIDIZATION COLUMN
Shahid Hussain, Najaf Ali, Rana Mujahad Saleem, Mahmood Saleem
http://111.68.103.26//journals/index.php/jfet/article/view/960
Abstract
Biomass & sand mixtures are used in a circulating fluidized bed reactor/fast fluidized bed reactor. Hydrodynamics of the system is important in the operation and design of fluidized bed reactor. In this study, hydrodynamics of biomass (cotton stalk, maize stalk and saw dust) and sand mixture was investigated in a bench scale cold test rig. The particle size of sand and biomasses were -30, +60 mesh. Superficial velocity was plotted against the pressure drop per unit bed height to determine the minimum fluidization velocity. The pressure drop per unit bed height increased sharply to a maximum value and then eventually dropped as the bed became fully fluidized. Velocities were calculated for various biomass compositions of 0.50, 0.75, 1.0 and 1.25 % and compared with the predicted values by published correlations. The experimental and estimated values were in close agreement.
Arabian journal for science and engineering
27 The Production of Al(OH)3 from Indigenous High-Silica Bauxite
Rofice Dickson, Mahmood Saleem, Muhammad Arif Bhatti
https://link.springer.com/article/10.1007/s13369-016-2388-8
Abstract
Aluminum hydroxide finds many industrial applications. Bauxite contains minerals from which aluminum hydroxide is leached through Bayer process. Impurities present in it are crucial toward the yield and purity of the end product. Indigenous bauxite ore found at Khushab, Punjab Quarry, was analyzed by X-ray fluorescence (XRF) and X-ray diffraction techniques. Effect of molar ratio, temperature and lime on product yield and purity of the product was investigated. Product samples were characterized by XRF spectroscopy method. Results revealed a product yield of 86% at , 1.95 molar ratio and 10% lime. The silica content of the product was below 0.4% under these conditions. Lime was found helpful in controlling the solubility of impurities in the caustic soda solution.
Polish Journal of Chemical Technology, 18, 3, 88—96, 10.1515/pjct-2016-0053
26 Effect of operating parameters on production of bio-oil from fast pyrolysis of maize stalk in bubbling fl uidized bed reactor
Najaf Ali, Mahmood Saleem, Khurram Shahzad, Sadiq Hussain, Arshad Chughtai
ABSTRACT
The yield and composition of pyrolysis products depend on the characteristics of feed stock and process operating parameters. Effect of particle size, reaction temperature and carrier gas fl ow rate on the yield of bio-oil from fast pyrolysis of Pakistani maize stalk was investigated. Pyrolysis experiments were performed at temperature range of 360–540°C, feed particle size of 1–2 mm and carrier gas fl ow rate of 7.0–13.0 m3 /h (0.6–1.1 m/s superfi cial velocity). Bio-oil yield increased with the increase of temperature followed by a decreasing trend. The maximum yield of bio-oil obtained was 42 wt% at a temperature of 490°C with the particle size of around 1.0 mm and carrier gas fl ow rate of 11.0 m3 /h (0.9 m/s superfi cial velocity). High temperatures resulted in the higher ratios of char and non-condensable gas.
Combustion Science and Technology
K Shahzad, M Saleem, Mohsin Kazmi, Zulfiqar Ali, S Hussain, NA Akhtar
https://www.tandfonline.com/doi/full/10.1080/00102202.2016.1190344
ABSTRACT
Share of renewable energy targets and global pollutant emissions are driving the increased utilization of CO2 neutral biomass. Effect of operating conditions like solid circulation rate, Ca/S molar ratio, and fluidizing velocity on emissions of NOx, SO2, and CO for burning different blends of wheat straw and Salt Range coal under fast fluidized bed conditions in a pilot scale test facility are reported in this study. Effect of bed temperature, excess air ratio, and secondary to primary air ratio on the emissions has already been published in the journal Combustion Science and Technology. In this study emissions of NOx, SO2, and CO were found to decrease with the increased wheat straw ratio and solid circulation rate. SO2 and NOx emissions were observed to decrease with the decrease in fluidizing gas velocity while tradeoff relationship was found between the NOx and CO emissions with the increase in Ca/S molar ratio.
KEYWORDS:
Journal of Faculty of Engineering & Technology
24 Estimation of Producer gas from low-grade coal and biomass using Mathematical Modeling
Sadiq Hussain, Khurram Shahzad, Niaz Ahmad Akhtar, Mehmood Saleem, Akhtar Ali Karlu, Najaf Ali
http://111.68.103.26//journals/index.php/jfet/article/view/642
Abstract
Sustainable energy and reduction in greenhouse gases (GHG) are the challenging issues of the world. Due to the increase in globing warming concern, the industrial world has already reduced the use of fossil fuels to the status of minimal source of energy. Biomass is now believed to be an economically competitive with the fossil fuels, which can be subsequently used for the production of producer or syngas using appropriate technology of thermal conversion. The low energy contents of biomass are compensated by blending with a higher energy content coal. The major objective of this study was to better understand the effect of Temperature change on the producer gas composition in circulating fluidized bed gasifier (CFBG). Primarily the current work is experimental, but supplemented by the mathematical modeling that explains different steps in terms of existing scientific knowledge. The validation results showed that the model predicted the molar ratio of H2/CO in the producer gas in the range 0.97, 0.96, 0.93, 0.92, 0.927 and the measured values 0.83, 0.79, 0.78, 0.73 and 0.74 at temperature degree (°C) 750, 800, 820, 850 and 875 respectively. Similarly the molar ratio of CO/CO2 predicted by the model was; 0.81, 0.84, 0.86, 0.89 and 0.85 against the experimental molar ratio 0.86, 0.91, 0.75, 0.66 and 0.59 respectively at fixed feed and ER value.
Arabian Journal for Science and Engineering
23 Bio-oil production from fast pyrolysis of cotton stalk in fluidized bed reactor
Najaf Ali, Mahmood Saleem, Khurram Shahzad, Arshad Chughtai
https://link.springer.com/article/10.1007/s13369-015-1801-z
Abstract
Fast pyrolysis was used to convert waste biomass into bio-oil, which has a benefit of storage and transportation with the potential as a fossil oil substitute. Pakistani cotton stalk was pyrolyzed in a bench-scale bubbling fluidized bed reactor. The effect of reaction conditions such as temperature and feed size on the bio-oil, char and gas yields was investigated. The optimal pyrolysis temperature for the production of bio-oil was 490 °C which gave the maximum yield (36 wt%) of product at feed size of 1.0 mm. Bio-oil yield increased with the increase in temperature, while the yield of char decreased. The various properties of bio-oil attained under these pyrolysis conditions were defined. Chemical composition of bio-oil was determined using FTIR and GC–MS analysis, and major chemical compounds were phenols, carboxylic acids, ketones, aldehydes, furans and sugars.
Combustion Science and Technology
K Shahzad, M Saleem, M Ghauri, J Akhtar, N Ali, NA Akhtar
https://www.tandfonline.com/doi/full/10.1080/00102202.2014.1002561
Abstract
Fuel diversity and reduction in pollutant emissions are driving the increased utilization of CO2 neutral biomass. Effects of operating conditions, such as bed temperature; excess air ratio; and secondary to primary air ratio on emissions of NOx, SO2, and CO for burning different blends of wheat straw and Salt Range coal under fast fluidized bed conditions in a pilot scale test facility, are reported in this study. Emissions of NOx were found to decrease with an increase in wheat straw ratio and secondary to primary air ratio. SO2 and CO emissions were observed to decrease with an increase in excess air ratio and wheat straw ratio.
Keywords:
BiomassCo-combustionEmissionsFast fluidizationHydrodynamics
Journal of Pakistan Institute of Chemical Engineers
21 Effect of Temperature on the Bio Oil Yield from Pyrolysis of Maize Stalks in Fluidized Bed Reactor
Najaf Ali, Mahmood Saleem, Khurram Shahzad, Rana Mujahid Saleem, Arshad Chughtai
Abstract
Fast pyrolysis is used to convert the waste biomass into liquid fuel which has a benefit of storage and transportation with the potential as a fossil oil substitute. Pakistan is an agricultural based country producing about 69 million tons of agricultural residues such as wheat straw, rice straw, cotton stalk, maize stalk and sugar cane trash etc. per year. Fast pyrolysis experiments are carried out in a bench scale fluidized bed reactor. The effect of temperature on the bio oil yield is studied. Bio oil yield increases with the rise of temperature from 361 to 510°C and yield of char decreases whereas that of gas is also increased. The maximum bio oil yield is 42 wt.% at the optimum temperature of 510°C. Chemical composition of bio oil produced from the pyrolysis of maize stalks is determined using GC-MS and FTIR analysis whereas coproducts such as incondensable gas and charcoal are characterized using GC analyzer and bomb calorimeter.
Advances in Chemical Engineering and Science
Khurram Shahzad, Mahmood Saleem, Moinuddin Ghauri, Waqar Ali Khan, Niaz Ahmed Akhtar
https://www.scirp.org/html/6-3700467_47593.htm
ABSTRACT
Fluidized bed combustion behavior of coal and biomass is of practical interest due to its significant involvement in heating systems and power plant operations. This combustion behavior has been studied by many experimental techniques along with different kinetic models. In this study, SO2 emissions have been studied out in a pilot scale test facility of Circulating Fluidized Bed combustor (70 KW) under fast fluidized bed conditions burning coal with Pakistani wheat straw. One dimensional Mathematical model is being developed to predict the SO2 emissions under different operating conditions like bed temperature, Ca/S molar ratio, solids circulation rate, excess air ratio and secondary to primary air ratio. These parameters are varied to validate the model and encouraging correlation is found between the experimental values and model predictions.
Keywords: Fast Fluidization, Emissions, Modelling
Chemical Engineering & Technology
19 On the Stability of Pulse‐Jet Regenerated‐Bag Filter Operation
Mahmood Saleem, Gernot Krammer
https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.201100516
Abstract
Problems with the pulse-jet bag filter operation have a direct influence on process plant operation and may result in loss of production time. Therefore, long-term stable operation of the plant is desirable for both the manufacturers and operators. The effects of operating parameters are studied experimentally on filter operation with regeneration between the upper and lower pressure drop limits. Many combinations were identified when the filter operation derailed from stable to unstable operation on changing one of the operating parameters. Filtration velocity, pulse pressure, and the upper limit of pressure drop had the potential of creating instability. A threshold detachment overpressure existed below which the operation led to unstable conditions at a certain filtration velocity and which increased with increasing velocity.
Powder Technology
18 Influence of operating parameters on cake formation in pilot scale pulse-jet bag filter
Mahmood Saleem, Gernot Krammer, Rafi Ullah Khan, M Suleman Tahir
https://www.sciencedirect.com/science/article/pii/S0032591012000897
Abstract
Bag filters are commonly used for fine particles removal in off-gas purification. There dust laden gas pervades through permeable filter media starting at a lower pressure drop limit leaving dust (called filter cake) on the filter media. The filter cakeformation is influenced by many factors including filtration velocity, dust concentration, pressure drop limits, and filter media resistance. Effect of the stated parameters is investigated experimentally in a pilot scale pulse-jet bag filter test facility where lime stone dust is separated from air at ambient conditions. Results reveal that filtration velocity significantly affects filter pressure drop as well as cake properties; cake density and specific cake resistance. Cake density is slightly affected by dust concentration. Specific resistance of filter cake increases with velocity, slightly affected by dust concentration, changes inversely with the upper pressure drop limit and decreases over a prolonged use (aging). Specific resistance of filter media is independent of upper pressure drop limit and increases linearly over a prolonged use.
Chemical Engeering & Technology
17 Measurement and Simulation of Axial Velocity in a Filter Bag
Mahmood Saleem, Gernot Krammer, Muhammd Suleman Tahir
https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.201200287
Abstract
The axial velocity in two different tests with pulse-jet bag filters made of needle felts on a pilot-scale test facility separating limestone dust from air under ambient conditions is measured and simulated at different cake area loads. Results reveal that the axial velocity profiles are not truly linear along the whole length of the bag. A nonuniform gas flow prevails when the bags are differently dust-loaded. The same behaviors are observed even at the end of filtration cycles at different upper pressure drop limits. At the higher upper limit, the nonuniformity is stronger. Radial velocity profiles are nearly symmetric along the length of the bag.
Powder Technology
16 Effect of Operating Parameters on Resistance Parameters of Filter Media and Limestone Dust Cake for Uniformly Loaded Needle Felts in a Pilot Scale Test Facility at Ambient Conditions
Mamood Saleem, Gernot Krammer, Muhammad Suleman
https://www.sciencedirect.com/science/article/pii/S0032591012003099
Abstract
Resistance parameters are essential for the prediction of pressure drop in bag filters. The reported values for limestone dust differ in magnitude and also depend on operating parameters. In this work, experimental data is provided from a pilot scale pulse-jet regenerated bag filter test facility for three types of needle felts using air and limestone dust at ambient conditions. Results reveal that specific resistance of filter media is independent of velocity while the specific resistance of filter cake increases linearly with filtration velocity. Residual pressure drop is almost constant, independent of upper pressure drop limit. The cake resistance at constant velocity fits to a second degree polynomial whereas it increases linearly with the velocity. A linear relation is reported here for all the cases. The resistance of filter cake decreases at higher upper pressure drop limit.
Chemical Engineering and Processing: Process Intensification
Muhammad Suleman Tahir, Mahmood Saleem, Shahid Raza Malik, Javaid Rabbani Khan, Matthäus Siebenhofer
https://www.sciencedirect.com/science/article/pii/S0255270111002704
Abstract
The degradation of hazardous pollutants (organic pollutants/non-biodegradable) in waste water was investigated with wet tube-type electrostatic precipitator (WESP). A WESP equipped with brush discharge electrodes was investigated under various operation conditions to characterize the current/voltage-curves and it was compared with the state of the art empirical correlation mentioned in literature. Experimentally obtained current/voltage data was modeled to develop an adjusted empirical correlation for brush type discharge electrodes. Investigations show that corona current is a function of operation voltage and geometry of discharge electrode. Formation of oxidizing reagents like ozone was investigated and the process was optimized. Degradation of several pollutants like acetone, EDTA and phenol was recorded at specific corona current. A series of investigations was conducted to determine the optimum process conditions without sparking. Degradation rate of organic pollutants is higher in the dominating region of ozone formation. WESP equipped with brush discharge electrode produce an enhanced/uniform corona which is capable of eliminating pollutants from off-gas and wastewater simultaneously.
Journal of Electrostatics
M Suleman Tahir, M Saleem, M Siebenhofer
https://www.sciencedirect.com/science/article/pii/S0304388611001999
Abstract
This project presents the results of investigation of current/voltage characteristics of brush type discharge electrodes (BTDE) in tube type electrostatic precipitators and the effect on operation. Experimental investigations were conducted with discharge electrodes of different wire diameter and different brush diameter. The effect of electrode geometry on current/voltage behavior was recorded. Corona current with brush type discharge electrodes was modeled and compared with experimental data. Brush type discharge electrodes produce an enhanced corona current compared with wire type discharge electrodes. Limited enhanced corona has improving effect on collection efficiency. An adjusted correlation was therefore deduced from experimentally obtained current/voltage data with BTDE.
Powder Technology
Mahmood Saleem, Rafi Ullah Khan, M Suleman Tahir, Gernot Krammer
https://www.sciencedirect.com/science/article/pii/S0032591011004463
Abstract
Pulse-jet bag filters are frequently employed for particle removal from off gases. Separated solids form a layer on the permeable filter media called filter cake. The cake is responsible for increasing pressure drop. Therefore, the cake has to be detached at a predefined upper pressure drop limit or at predefined time intervals. Thus the process is intrinsically semi-continuous. The cake formation and cake detachment are interdependent and may influence the performance of the filter. Therefore, understanding formation and detachment of filter cake is important. In this regard, the filter media is the key component in the system. Needle felts are the most commonly used media in bag filters. Cake formation studies with heat treated and membrane coated needle felts in pilot scale pulse jet bag filter were carried out. The data is processed according to the procedures that were published already [Powder Technology, Volume 173, Issue 2, 19 April 2007, Pages 93–106]. Pressure drop evolution, cake height distribution evolution, cake patches area distribution and their characterization using fractal analysis on different needle felts are presented here. It is observed that concavity of pressure drop curve for membrane coated needle felt is principally caused by presence of inhomogeneous cake area load whereas it is inherent for heat treated media. Presence of residual cake enhances the concavity of pressure drop at the start of filtration cycle. Patchy cleaning is observed only when jet pulse pressure is too low and unable to provide the necessary force to detach the cake. The border line is very sharp. Based on experiments with limestone dust and three types of needle felts, for the jet pulse pressure above 4 bar and filtration velocity below 50 mm/s, cake is detached completely except a thin residual layer (100–200 μm). Uniformity and smoothness of residual cake depends on the surface characteristics of the filter media. Cake height distribution of residual cake and newly formed cake during filtration prevails. The patch size analysis and fractal analysis reveal that residual cake grow in size (latterly) following regeneration initially on the base with edges smearing out, however, the cake heights are not leveled off. Fractal dimension of cake patches boundary falls in the range of 1–1.4 and depends on vertical position as well as time of filtration. Cake height measurements with Polyimide (PI) needle felts were hampered on account of its photosensitive nature.
JOURNAL OF FACULTY OF ENGINEERING & TECHNOLOGY
Javeed Ashraf Awan, Mahmood Saleem
http://111.68.103.26//journals/index.php/jfet/article/view/66
Abstract
Most of the thermodynamic models are structured with terms representing long range interactions or intermediate/short range interactions only. Thus for the proper thermodynamic presentation of electrolyte systems, all different types of interactions: ion-ion, ion-dipole, dipole-dipole, molecule-molecule should be taken into account. The potential energy caused by ion-ion interactions is inversely proportional to the separation between them. Electrostatic ion-ion interactions therefore are effective over a relatively long distance called as long range interactions. A review of the literature was conducted to find the available models, correlations: capable of describing the phase behavior and thermo physical properties of strong as well as weak electrolyte systems. In this work the comparative study for the models that has been used for describing the Phase behavior of acid gases and sulfur species in alkanolamine aqueous solutions. These kinds of models are of high interest for the absorption unit in the natural gas processing industry
JOURNAL OF FACULTY OF ENGINEERING & TECHNOLOGY
Waqar Ali Khan, Khurram Shahzad, Mahmood Saleem, Niaz Ahmed Akhter, Muhammad Suleman Tahor
http://111.68.103.26//journals/index.php/jfet/article/view/97
Abstract
In the present paper, a detailed parametric study is conducted on the radial heat transfer studies in a locally fabricated circulating fluidized bed combustor by burning Makarwal coal. The variations of radial heat transfer coefficients in a CFB combustor with different operating parameters are investigated. The experimental set up consists of a riser of a circulating fluidized bed (152 mm ID and 6 m high). A radial heat transfer probe (2" thick & 15.4 cm ID) was used for these investigations. Silica sand of 2500 Kg/m3 and having average particle size of 125 µm is used as bed material. A detail radial temperature profile was also investigated during the experimental runs. It was found that radial heat transfer coefficient increased with increase in suspension density, bed temperature and solid circulation rate.
Chemie Ingenieur Technik
MS Tahir, M Saleem, M Siebenhofer
https://onlinelibrary.wiley.com/doi/abs/10.1002/cite.201050645
JOURNAL OF FACULTY OF ENGINEERING & TECHNOLOGY
Mah-e Kamil, Mahmood Saleem, Sahibzada Rashid Hameed, Zahoor Ul Hassan Rizvi
http://111.68.103.26/journals//index.php/jfet/article/view/16
Abstract
Properties of the finished products like paper and board depend on parameters namely cooking liquor concentration, the chemicals and temperature in the digester. In this study digestion of wheat straw is investigated experimentally in sulphite process by varying alkali ratio keeping all other parameters constant. Resulting pulp is characterized by a set of properties (percentage yield, consistency, Kappa No., SR and Ash content). Results reveal that the best combination of properties can be achieved at alkali ratio of 10.5 % NaOH and 3.5%Na2SO3.
Journal of Pakistan Institute of Chemical Engineers
Experimental study of the effect of stack area on thermal performance of storage type water heaters burning natural gas
Ahsan Riaz, Mahmood Saleem
https://www.piche.org.pk/journal/index.php/jpiche/article/view/22
Abstract
Water heating represents a significant use of energy in the world. One way of generating hot water for residential buildings is the use of storage type gas fired water heater. The performance of this equipment is still a research object in Pakistan. Appliances on the market e.g. gas water heaters are not much efficient due to certain losses and thus consume considerable amount of natural gas. Pakistan’s total remaining gas reserves are adequate for meeting gas requirements of the country for 20 years at current rate (5289 MMCFD) of production. In this context, an experimental program is underway to evaluate the thermal performance of gas fired storage-type water heaters. These water heaters have the same design but only differ in their stack area and its division. The target is to determine which heater has high thermal performance at its optimum operating conditions.
Journal of Quality and Technology Management
MN Younis, MS Saeed, S Khan, MU Furqan, RU Khan, M Saleem
Abstract Biodiesel production was carried out by using vegetable oil (Mustard, Soybean, Canola, Waste vegetable oil).To characterize the biodiesel produced, different ASTM standard tests were carried out. Besides standard tests, FTIR (Fourier Transform Infra Red) spectrophotometry of biodiesel was also performed. Results reveal that characteristics of biodiesel depend on the feed stock. The best combination of properties is obtained from Canola oil based Biodiesel. Biodiesel produced from waste vegetable oil was also found very convenient to be used and properties were comparable to an ordinary diesel fuel (mineral diesel).
Key Word: Transesterification, Biodiesel, Characterization, Waste Oil
Journal of Pakistan Institute of Chemical Engineers
RU Khan, M Saleem, A Shafeeq
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.piche.org.pk/journal/vol2009/piche-3.pdf
ABSTRACT
Vacuum gas carburizing is an important industrial process used for hardening the steel parts. The addition of carbon to the steel parts is accomplished by the pyrolysis of gaseous hydrocarbons. The gas phase composition is very important in vacuum gas carburizing to control the process. Pyrolysis of gaseous hydrocarbons is a complex process because of large number of reactions which lead to the formation of large number of species. To model such processes special software tools have been developed which can be used with detailed kinetics models. The present work focuses on modeling the gas phase reactions in a bench scale reactor used for vacuum gas carburizing of steel with acetylene.
Key words: Acetylene, Pyrolysis, Modeling, Simulation, Vacuum Carburizing
Particle & Particle Systems Characterization
Michael Koch, Mahmood Saleem, Gernot Krammer
https://onlinelibrary.wiley.com/doi/abs/10.1002/ppsc.200601068
Abstract
The measurement of a distributed property is frequently encountered in engineering applications. The impact of a possible measurement error on the measured distribution is described and two methods to account for such an error are detailed: A Fourier transform based deconvolution procedure and a moment based deconvolution approach via kernel estimators are presented. The deconvolution methods can be used in many particle characterization and process applications where particle features or properties are commonly presented in a distributed form. In the current instance, these methods are carefully explored by using artificially generated data and applied to experimental data obtained from filter cake thickness measurements.
Journal of hazardous materials
Mahmood Saleem, Gernot Krammer
https://www.sciencedirect.com/science/article/abs/pii/S0304389407001616
Abstract
Bag filters are used for the removal of fine solid particles from process gases. Thus, understanding the filter cake build up and its properties is a subject of interest. The filter cakes properties may depend on many factors like, for example, filtration velocity and dust concentration. The effect of dust concentration and filtration velocity on filtration time, specific cake resistance and mean cake density is investigated in a pilot scale jet pulsed bag filter. An in situ optical system is used to measure cake thickness distributions on the filter surface. Additionally, the operation is simulated using a one-dimensional model and results are compared with experiments. The experimental results indicate that cake density and specific resistance increase with increasing velocity at constant dust concentration. The effect of dust concentration on filter cake density and specific resistance is small.
Powder Technology
Mahmood Saleem, Gernot Krammer
https://www.sciencedirect.com/science/article/abs/pii/S0032591006005468
Abstract
A pilot scale jet pulsed bag filter test facility is operated at conditions similar to those of the industrial bag filters. The facility is equipped with a stereo vision based optical system for in-situ cake height distribution measurements on the bag filter surface. Experimental data are presented and data evaluation procedures are discussed to elaborate the features of the measuring system. The results show that the cake height distribution becomes narrower towards the end of filtration cycles. A steep pressure drop rise is observed at the start of a filtration cycle in the absence of re-attachment and a non-uniform bag cleaning, which may be attributed to different cake properties. The specific cake resistance remains constant over the linear part of the pressure drop curve indicating a non-compressible cake formation. The analysis of residual cake patches shows a large number of small sized cake patches and a few large sized cake patches on the filter surface. The cake patch size increases with the cake formation. The fractal analysis of patches boundary indicates preferential cake formation at the boundary of the residual cake patches shortly after regeneration.
Journal of faculty of engineering & Technology
Ali Ahmed, Naseer Ahmad, Rizwan Shah, M Naeem Bhatti, Mahmood Saleem
ABSTRACT
Coal desulfurization prior to usage is a preprocessing in order to achieve clean fuel and reduce environmental impacts such as acid rain. Desulfurization of Lakhra (Pakistan) coal was conducted with different solvents. Coal was leached with different solvents like hot water, H2O2/H2SO4 and HNO3. It was found that the effects of the leaching temperature, agitation time and particle size on the removal of different forms of sulfur are very significant. Sulfur recovery increases with agitation time, temperature and mesh number up to a certain optimum value and then have a different trend.
Assembly Automation
In-situ measurement of dust deposition on bag filters using stereo vision and non-rigid registration
Matthias Rüther, Mahmood Saleem, Horst Bischof, Gernot Krammer
ABSTRACT
Presents a machine vision system in terms of hard‐ and software which is capable of obtaining the relative height difference of a cloth filter surface in different states of operation. The measurement process starts with a stereo reconstruction of filter surface patches. The patches are aligned to form a continuous model using the iterative closest point algorithm. Models acquired at different states of operation are registered using thin plate spline interpolation and afterwards subtracted from each other to obtain the relative height difference.