27 results on '"Imran Nazir Unar"'
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2. Effect of Aloe Vera Extract as Green Corrosion Inhibitor on Medium Carbon Steel in Sulphuric Acid Environment
- Author
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Suhail Mashooque Odhano, Mukesh Kumar, and Imran Nazir Unar
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Environmental Chemistry ,Analytical Chemistry - Abstract
Medium carbon steel is widely consumed by various industrial sectors due to its attractive set of mechanical properties and low cost, but it experiences deterioration when exposed to a corrosive environment. In the present study, Aloe Vera plant extract was studied as a green corrosion inhibitor for medium carbon steel in an acidic medium. The presence of inhibitive compounds in Aloe Vera plant extract was determined by FTIR. Moreover, the inhibition efficiency was determined through gravimetric analysis and electrochemical analysis. The results show that the Aloe Vera plant extract provided inhibition efficiency of more than 90% in both gravimetric and electrochemical analyses. Furthermore, the shift in polarization curves depicts that this plant extract is a mixed type inhibitor acting as an anodic and cathodic inhibitor. Overall, Aloe Vera plant extract provides excellent corrosion inhibition to medium carbon steel in the H2SO4 environment and can be used as a green corrosion inhibitor for mitigating internal corrosion of pipelines and storage tanks.
- Published
- 2022
3. Modeling and simulation of juice clarifier using computational fluid dynamics for enhanced sugar quality
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Imran Nazir Unar, Ghulamullah Maitlo, Masroor Abro, Imran Ali, Abdul Qadeer Laghari, Zulfiqar Ali Solangi, Naveed Ali Koondhar, Nadia Mustaqim Ansari, and Jong-Oh Kim
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General Chemical Engineering - Published
- 2023
4. Large Eddy Simulation of Modified Leading Edge Tubercle Design Airfoil Under Deep Stall
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Intizar Ali, Tanweer Hussain, and Imran Nazir Unar
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- 2023
5. Kinetic modeling of gasification reactions of CO2 and H2O for Thar lignite char at elevated pressures
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Rasool Bux Mahar, M. Aslam Uqaili, Ghulamullah Maitlo, Imran Nazir Unar, and Abdul Ghani Pathan
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Materials science ,General Chemical Engineering ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Activation energy ,010402 general chemistry ,Kinetic energy ,01 natural sciences ,Biochemistry ,Industrial and Manufacturing Engineering ,symbols.namesake ,Materials Chemistry ,Coal ,Char ,Quartz ,Arrhenius equation ,Atmospheric pressure ,business.industry ,General Chemistry ,021001 nanoscience & nanotechnology ,Nitrogen ,0104 chemical sciences ,chemistry ,symbols ,0210 nano-technology ,business - Abstract
Gasification reactions of Thar coal chars with CO2 and H2O have been investigated, using pressurized thermo-gravimetric analyzer (PTGA). A quartz fixed-bed reactor was used to prepare coal char at 900 °C with a nitrogen environment. Dynamic heating segments were maintained with a constant heating rate during all experiments. The temperature was raised from room temperature to 1000 °C, at different pressures 1 atm., 5 atm., and 10 atm. using pure reacting gases (CO2 and H2O). The weight loss data obtained from PTGA results were used to study the kinetic behavior of Thar lignite char for gasification reactions with CO2 and H2O as gasifying reacting species. It was observed that gasification reactions of char with reacting gas CO2 and char with reacting gas steam (H2O) initiated at 750 °C and completed after reaching 950 °C, at atmospheric pressure, but the occurrence of reactions was slightly delayed at high pressures. Volumetric Model and Grain Model were used to develop a kinetic model for Thar lignite. The direct plot and integral methods were used to calculate Arrhenius parameters such as the pre-exponential factor (A) and activation energy (E). An increase of A and E was also observed in increasing pressures. The activation energy (E) was investigated from 244.64 to 317.6 kJ/mol at atmospheric pressure; whereas, it is lying in the range of 286.13–356.67 kJ/mol at a pressure of 10 atm.
- Published
- 2020
6. Experimental study and dynamic simulation of melanoidin adsorption from distillery effluent
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Shoaib Ahmed, Abdul Qayoom Memon, Rasool Bux Mahar, Hassnain Abas Khan, Abdul Sattar Jatoi, Imran Nazir Unar, Abdul Karim Shah, and Ghulamullah Maitlo
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Langmuir ,Polymers ,Health, Toxicology and Mutagenesis ,010501 environmental sciences ,Coal Ash ,01 natural sciences ,symbols.namesake ,Adsorption ,Environmental Chemistry ,Freundlich equation ,Effluent ,0105 earth and related environmental sciences ,Chemistry ,Melanoidin ,Langmuir adsorption model ,General Medicine ,Hydrogen-Ion Concentration ,Pollution ,Dilution ,Kinetics ,Coal ,Chemical engineering ,Fly ash ,symbols ,Water Pollutants, Chemical - Abstract
This work aims to utilize fly ash from a thermal power station for melanoidin reduction from distillery effluent by adsorption. To accomplish this, coal fly ash was modified through chemical treatment and was then tested for melanoidin adsorption as a function of various melanoidin concentrations, contact time, and pH. The specific novelty of this study is the evaluation of coal fly ash as a low-cost adsorbent for melanoidin removal. Furthermore, the simulation study was carried out using Aspen ADSIM software in order to optimize the commercial usage of the prepared adsorbent. The main results achieved include the maximum removal efficiency of 84% which was reached at initial melanoidin concentration of 1100 mg L−1 (5% dilution), pH 6, and a contact time of 120 min. The Langmuir and Freundlich isotherm models were used to evaluate adsorption isotherms. The maximum adsorption capacity of 281.34 mg/g was observed using the Langmuir isotherm. Furthermore, pseudo-first- and pseudo-second-order and intra-particle diffusion models were used to fit adsorption kinetic data. The pseudo-second-order was best describing the adsorption kinetic with a faster kinetic rate of 0.142 mg g–1 min−1. CFA (coal fly ash) after acidic activation resulted in a slightly higher surface area, average pore volume, and pore size. The maximum breakthrough time and adsorbent saturation time were achieved at initial melanoidin concentration of 1 mol/lit, bed height of 2.5 m, and flow rate of 50 lit/min.
- Published
- 2020
7. Impacts of slurry and dry forms of low-rank coal (lignite) on quality of syngas produced
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Syed Abdul Karim Shah, Ghulamullah Maitlo, Zulfiqar Ali Bhatti, Rasool Bux Mahar, Shaheen Aziz, Suhail Ahmed Soomro, Mohammad Safar Korai, and Imran Nazir Unar
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Economics and Econometrics ,Environmental Engineering ,Municipal solid waste ,Wood gas generator ,Waste management ,business.industry ,020209 energy ,Biomass ,Fraction (chemistry) ,02 engineering and technology ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,Raw material ,01 natural sciences ,General Business, Management and Accounting ,0202 electrical engineering, electronic engineering, information engineering ,Slurry ,Environmental Chemistry ,Environmental science ,Coal ,business ,0105 earth and related environmental sciences ,Syngas - Abstract
Gasification is one of the prominent and technically efficient technologies for converting solids like coal, biomass or solid waste into useful gas known as “syngas.” Several configurations are in use today among which entrained flow gasifiers have several advantages over other configurations. Presently research is more focused on micro-level modifications in the configurations which have a significant impact on overall performance of gasification. Scant, literature is available for comparison of slurry over dry form of feedstocks, especially with low-grade coals. Hence, present research aims to establish a concrete finding regarding the impacts of slurry versus the dry condition of coal on the overall performance of gasification. To achieve this goal, a two-dimensional computational fluid dynamic (CFD) model of downdraft gasifier was developed in commercial CFD software FLUENT for performing numerical simulations with indigenous coal feedstock. Rich oxidant conditions (95% oxygen and 5% nitrogen) were maintained in the gasifier for the gasification. The performance of gasification was measured by comparing efficiencies of gasification and the quality of syngas produced with different coal forms. As per simulation results, coal forms and operating conditions caused a significant effect on overall gasification performance. In syngas composition, H2 mol fraction reached at maximum, when the slurry form of coal was used for gasification. This effect is remarkable for generating hydrogen-rich fuel from lignite without consuming steam externally.
- Published
- 2020
8. Investigation of Performance for Entrained Flow Gasifier Through Simulations
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Imran Nazir Unar, Suheb Ali Rajper, Azizullah Channa, and Zulfiqar Ali Bhatti
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Wood gas generator ,lcsh:T ,020209 energy ,Flow (psychology) ,02 engineering and technology ,Mechanics ,021001 nanoscience & nanotechnology ,lcsh:Technology ,complex mixtures ,respiratory tract diseases ,lcsh:TA1-2040 ,otorhinolaryngologic diseases ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,lcsh:Q ,lcsh:Engineering (General). Civil engineering (General) ,lcsh:Science ,0210 nano-technology ,General Agricultural and Biological Sciences - Abstract
Pakistan has proven huge coal reserves but still unable to harvest the energy due to unavailability of ingenious technology. Coal gasification is robust, efficient and environmental friendly technology but it is highly sensitive to the coal characteristics. Scant literature is available on the development of the coal gasification technology which suits the characteristics of indigenous coal reserves. This papers presents the simulation of entrained flow gasifier for using indigenous coal through process modeling software namely Aspen Plus® to evaluate various system flow steps within an entrained flow gasifier. General techniques have also been discussed for creating the equilibrium-bases simulations of gasification systems. Peng-Robinson equation was used to correlate the volume of species with respect to state variables (temperature and pressure). The effects of composition of different indigenous coals like Thar, Lakhra and Sonda were investigated through simulations along with O/C (Oxygen-to-Carbon) ratio. Parametric study revealed that the O/C ratio along with other related system parameters have great influence on the performance. Sulfur could be available in different forms in coal like pyrite, sulfate or organic sulfur so appropriate form of sulfur in feedstocks should be corrected for better accuracy of model results. The highest percentages of CO i.e. 44.2, 37.8, and 46.6% were obtained from Thar coal (air dried form), Lakhra coal and Sonda coal respectively at the 0.3 O/C ratio. The decrease in LHV and HHV (Lower and Higher Heating Values) of syngas was observed on increase of O/C ratio for all coal types. The composition of as received Thar coal gave maximum LHV (1.5x104 KJ/Kg) and HHV (1.78x104 KJ/Kg) at the 0.3 O/C ratio. The future work could be extended by simulating biomass composition in the developed model of gasifier in transient simulations.
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- 2020
9. Plastic Waste Recycling, Applications, and Future Prospects for a Sustainable Environment
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Ghulamullah Maitlo, Imran Ali, Hubdar Ali Maitlo, Safdar Ali, Imran Nazir Unar, Muhammad Bilal Ahmad, Darya Khan Bhutto, Ramesh Kumar Karmani, Shamim ur Rehman Naich, Raja Umer Sajjad, Sikandar Ali, and Muhammad Naveed Afridi
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Renewable Energy, Sustainability and the Environment ,Geography, Planning and Development ,Building and Construction ,Management, Monitoring, Policy and Law - Abstract
Plastic waste accumulation has been recognized as one of the most critical challenges of modern societies worldwide. Traditional waste management practices include open burning, landfilling, and incineration, resulting in greenhouse gas emissions and economic loss. In contrast, emerging techniques for plastic waste management include microwave-assisted conversion, plasma-assisted conversion, supercritical water conversion, and photo reforming to obtain high-value products. Problems with poorly managed plastic waste are particularly serious in developing countries. This review article examines the emerging strategies and production of various high-value-added products from plastic waste. Additionally, the uses of plastic waste in different sectors, such as construction, fuel production, wastewater treatment, electrode materials, carbonaceous nanomaterials, and other high-value-added products are reviewed. It has been observed that there is a pressing need to utilize plastic waste for a circular economy and recycling for different value-added products. More specifically, there is limited knowledge on emerging plastic waste conversion mechanisms and efficiency. Therefore, this review will help to highlight the negative environmental impacts of plastic waste accumulation and the importance of modern techniques for waste management.
- Published
- 2022
10. Citronellal cyclisation to isopulegol over micro-mesoporous zsm-5 zeolite: effects of desilication temperature on textural and catalytic properties
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Aqeel Ahmed Shah, Hassnain Abbas Khan, Rashid Mustafa Korai, Abdul Karim Shah, Imran Nazir Unar, Syed Farman Ali Shah, Usama Ismail, Ghulamullah Maitlo, and Yeung Ho Park
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010405 organic chemistry ,Chemistry ,010402 general chemistry ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Reaction rate ,chemistry.chemical_compound ,Adsorption ,Chemical engineering ,Citronellal ,Lewis acids and bases ,Physical and Theoretical Chemistry ,Mesoporous material ,Selectivity ,Zeolite - Abstract
In this work, desilication reassembly post treatment process was applied in synthesis of mesoporous zeolite with stable phase composition and applied it in citronellal cyclisation reaction for the production of isopulegol. The desilication and temperature effects were further investigated on physical and chemical characteristics of zeolite and compared them with catalytic activity. The desilicated zeolite samples have been characterized with the help of N2-adsorption, XRD, ICP-OES, pyridine adsorption and FTIR techniques. Its performance was explored by controlling operative parameters. Experimental outcomes exhibited that desilication of zeolite would led to formation of mesopores inside the stable zeolite framework structures without substantial damage of their internal composition. These changes facilitate mass transfer and catalytic activity with an increase in surface area, mesoporosity, pore size, pore volume, acidity, and Lewis acid sites. Optimum desilication temperature (80 °C) was found as a best for an comprising extra active and selective mesoporous zeolite catalyst for citronellal cyclisation. Thus, this type of zeolite material has shown 100% conversion (e.g. complete conversion of citronellal reactants to the desired products), 95% isopulegol selectivity and highest reaction rate (0.11 min−1). This study exhibits the mesoporous zeolite (MZ-80 °C) as one of the most effective catalyst for citronellal cyclization reaction based on assessment of catalytic performance relative to other commonly available options.
- Published
- 2019
11. Numerical simulation of lignocellulosic biomass gasification in concentric tube entrained flow gasifier through computational fluid dynamics
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Imran Nazir Unar, Rasool Bux Mahar, Khan Mohammad Brohi, and Ghulamullah Maitlo
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Computer simulation ,Wood gas generator ,Renewable Energy, Sustainability and the Environment ,business.industry ,lcsh:TJ807-830 ,Flow (psychology) ,lcsh:Renewable energy sources ,0211 other engineering and technologies ,Energy Engineering and Power Technology ,Biomass ,Lignocellulosic biomass ,02 engineering and technology ,Computational fluid dynamics ,021001 nanoscience & nanotechnology ,lcsh:Production of electric energy or power. Powerplants. Central stations ,Fuel Technology ,Nuclear Energy and Engineering ,lcsh:TK1001-1841 ,Environmental science ,Tube (fluid conveyance) ,021108 energy ,0210 nano-technology ,Process engineering ,business ,Syngas - Abstract
Thermochemical conversion of biomass is an encouraging way for the production of syngas. In the present research, four different biomass materials were used for gasification which includes rice husk, cotton stalks, sugarcane bagasse, and sawdust. These biomass sources were selected because they are common Pakistani feedstocks. Gasification of selected biomasses was performed using concentric tube entrained flow gasifier. Three-dimensional computational fluid dynamics model was used to investigate the impacts of kinetic rate and diffusion rate on the gasification performance. The Euler–Lagrange method was used for the development of entrained flow biomass gasifier using commercial computational fluid dynamics code ANSYS FLUENT®14. Discrete phase model was used to predict the movement of particles, whereas the gas phase was treated as the continuous phase with a standard k–ε turbulent model to predict the behavior of gas phase flow. Finite rate/Eddy dissipation model was applied for the calculation of homogenous and heterogeneous reaction rates. Oxygen was used as a gasifying agent. Cotton stalks and sugarcane bagasse produced higher mole fractions of hydrogen (H2) and carbon monoxide (CO) than sawdust and rice husk. Regarding carbon conversion efficiency, cold gas efficiency, and higher heating value cotton stalks and sugarcane bagasse produced better syngas quality as compared to sawdust and rice husk. The oxygen/fuel (O/F) ratio is a key operating parameter in the field of gasification and combustion. The O/F ratio above 0.42 favored combustion reactions and increased mole fraction of water vapor (H2O) and carbon dioxide (CO2) in syngas composition, whereas gasification reactions dominated below 0.42 O/F ratio, resulting increased mole fraction of H2 and CO in syngas composition.
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- 2019
12. Thermogravimetric analysis of Pakistani biomasses using nitrogen and oxygen as a carrier gas
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Imran Nazir Unar, Syed Abdul Karim Shah, and Ghulamullah Maitlo
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Thermogravimetric analysis ,General Chemical Engineering ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,Activation energy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Nitrogen ,Husk ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium ,Hemicellulose ,Sawdust ,Cellulose ,0210 nano-technology ,Pyrolysis - Abstract
Thermochemical characterization of four different biomasses sawdust (SD), rice husk (RH), cotton stalk (CS) and sugarcane bagasse (SB) was investigated to understand their kinetic characteristics. The TGA experiments were done using inert and oxidative atmospheres to understand the reaction kinetics of selected biomasses. The temperature was enlarged from room temperature to 900 °C at a heating rate of 10 °C min−1 under non-isothermal conditions. The weight loss of all the four biomass materials under an inert and oxygen environments showed alike weight loss trend occurring in three main stages. It was observed that all four biomass materials degraded in three identical regions. In the first region of weight loss, moisture evaporation was observed, in second region cellulose and hemicellulose degradation was achieved, whereas in third region lignin degradation was achieved under both an inert and oxy-combustion atmospheres at different temperature ranges. The activation energy, pre-exponential factors were evaluated through Arrhenius correlation equations. The values of E calculated during pyrolysis for CS, SB, SD and RH were 79.10, 68.32, 53.46, 52.9 (kJ mol−1) during oxy-combustion atmospheres 122.6, 106.31, 123.28 and 118 (kJ mol−1), respectively.
- Published
- 2018
13. Modeling and simulation of solar flat plate collector for energy recovery at varying regional coordinates
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Sheeraz Memon, Imran Nazir Unar, Kashif Hussain Mangi, Sikandar Ali Abbasi, Ghulamullah Maitlo, Raja Fahad Qureshi, Masroor Abro, and Tanveer Hussain
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Energy recovery ,Work (thermodynamics) ,Hot Temperature ,Meteorology ,business.industry ,Health, Toxicology and Mutagenesis ,Temperature ,Flux ,Water ,General Medicine ,Computational fluid dynamics ,Solar energy ,Pollution ,Tilt (optics) ,Solar Energy ,Environmental Chemistry ,Environmental science ,Working fluid ,Ray tracing (graphics) ,Pakistan ,business - Abstract
Pakistan has remained an energy-deficient country, and most of the industrial sectors are closed due to the loading shedding of electricity. Even though Pakistan is located on the “solar belt” and receives over 2 MWh/m2 solar irradiation per year with 1500–3000 h of sunshine, unfortunately solar energy is not harnessed to fulfill the energy needs of the country. Solar flat plate collectors (SFPC) are widely employed for collecting solar radiations from the sun. Currently, worldwide solar thermal energy is widely used in household and commercial equipment for energy collection and utilization. The working fluid selected for this research work is water; numerical simulations were performed using Ansys FLUENT. On selected geographical coordinates, solar ray tracing model was employed to incorporate solar heat flux. Nawabshah (NWB), Hyderabad (HYB), Jacobabad (JCB), and Mirpurkhas (MPK) cities were selected for the measuring of performance of SPFC. Firstly, parallel to ground (at a 0° tilt angle) orientation of SFPC was performed. Furthermore, the performance of SFPC was measured using tilt angles of 15°, 30°, and 45°, respectively. The maximum exit water temperature in JCB at a tilt angle of 30° was 97.8 °C in March and a minimum of 88.09 °C in June. In HYD, at a tilt angle of 45°, the maximum temperature rise was recorded at 98.01 °C in November and the minimum was noticed at 76.37 °C in June. While in JCA, at an angle of 30°, the highest temperature was recorded at 97.83 °C in February and a minimum of 78.54 °C in June. The specific aim of this research study was to measure the performance of the SFPC at different tilt angles and at varying geographical coordinates through numerical simulations.
- Published
- 2021
14. Thermochemical Conversion of Biomass for Syngas Production: Current Status and Future Trends
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Ghulamullah Maitlo, Imran Ali, Kashif Hussain Mangi, Safdar Ali, Hubdar Ali Maitlo, Imran Nazir Unar, and Abdul Majeed Pirzada
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Renewable Energy, Sustainability and the Environment ,Geography, Planning and Development ,Management, Monitoring, Policy and Law - Abstract
The thermochemical conversion of different feedstocks is a technology capable of reducing the amount of biowaste materials produced. In addition, the gasification of feedstock using steam as a gasifying agent also produces hydrogen, which is a clean energy fuel. This article aimed to encapsulate the current status of biowaste gasification and to explain, in detail, the advantages and limitations of gasification technologies. In this review paper, different gasifying agents such as steam, air, and oxygen, as well as their effects on the quality of syngas production, are discussed. In addition, the effects of reactor configuration and different operating parameters, such as temperature, pressure, equivalence ratio, and incorporation of a catalyst, as well as their effects on the ratio of H2/CO, LHV, syngas yield, and tar production, were critically evaluated. Although gasification is a sustainable and ecologically sound biomass utilization technology, tar formation is the main problem in the biomass gasification process. Tar can condense in the reactor, and clog and contaminate equipment. It has been shown that an optimized gasifier and a high-activity catalyst can effectively reduce tar formation. However, key biowaste treatment technologies and concepts must first be improved and demonstrated at the market level to increase stakeholder confidence. Gasification can be the driving force of this integration, effectively replacing fossil fuels with produced gas. In addition, support policies are usually needed to make the integration of biomass gasification technology into the industry profitable with fully functional gasification plants. Therefore, to address such issues, this study focused on addressing these issues and an overview of gasification concepts.
- Published
- 2022
15. Performance evaluation of solar flat plate collector using different working fluids through computational fluid dynamics
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Imran Nazir Unar, Abdul Sattar Jatoi, Abdul Qayoom Memon, Ghulam Abbas Kandhro, Syed Saad Ali, Ghulamullah Maitlo, and Shoaib Ahmed
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Thermal efficiency ,Materials science ,business.industry ,Turbulence ,General Chemical Engineering ,General Engineering ,Turbulence modeling ,General Physics and Astronomy ,Mechanics ,Computational fluid dynamics ,Volumetric flow rate ,Physics::Fluid Dynamics ,Continuity equation ,Physics::Space Physics ,General Earth and Planetary Sciences ,Working fluid ,General Materials Science ,Ray tracing (graphics) ,Astrophysics::Earth and Planetary Astrophysics ,business ,General Environmental Science - Abstract
The aim of this study involves establishing a three-dimensional computational fluid dynamic (3D-CFD) model of solar flat plate collector (SFPC) in order to investigate the effect of operating and geometric parameters on thermal efficiency. In this research work, commercial CFD code ANSYS FLUENT®14.0 version was used for the development of a model of solar plate collector. The single circular tube geometry was created using ANSYS DesignModeler®14.0. The general continuity equation along with Navied–Stokes equations was solved for tracking motion of the working fluid. The general k–e turbulence modeling approach was used for solving the turbulence in the flow. Solar ray tracing was activated for calculating solar load in the model. The latitude and longitude of the Hyderabad region were inserted in the solar ray-tracing model for calculating solar intensity as per local conditions. Two fluids i.e., water and air were circulated with different flow rates in the developed model of SFPC. It was observed that water gave higher efficiency due to high density and thermal conductivity. The simulation results gathered revealed that the temperature of water and air was raised by almost 79 °C and 73 °C respectively.
- Published
- 2020
16. Kinetic Study of Cotton Stalk and Rice Husk Samples under an Inert and Oxy Combustion Atmospheres
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Imran Nazir Unar, Ghulamullah Mailto, Rasool Bux Mahar, and Khan Muhammad Brohi
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Order of reaction ,lcsh:T ,020209 energy ,Thermal decomposition ,Analytical chemistry ,Biomass ,chemistry.chemical_element ,02 engineering and technology ,Activation energy ,Combustion ,Rice hulls ,lcsh:Technology ,Nitrogen ,Husk ,020401 chemical engineering ,chemistry ,lcsh:TA1-2040 ,0202 electrical engineering, electronic engineering, information engineering ,lcsh:Q ,0204 chemical engineering ,lcsh:Engineering (General). Civil engineering (General) ,lcsh:Science ,General Agricultural and Biological Sciences - Abstract
Biomass materials such as CS (Cotton Stalks) and RH (Rice Husk) are a renewable source of energy. As biomass resources have potential to offer a uninterpted supply of biofuels through thermal decomposition processes. Nevertheless, an appropriate understanding of reaction kinetics and thermal properties of biomasses play a vital role in designing of the commercial plants using biomass as a raw material for energy generation. The kinetic characteristics of the CS and RH samples under pure nitrogen 99.9% and pure oxygen 99.9% was performed. The temperature was raised from ambient to 900oC maintaining the heating rate of 10oC/min. CS and RH decomposition was noticed in three dissimilar regions. The kinetic characteristics such as (pre-exponential factor, the order of reaction and activation energy) were calculated for both selected materials. The activation energies calculated under nitrogen environment for CS and RH was 68.77 and 72.31 kJ/mole, whereas the regression coefficient (R2) was 0.9877 and 0.9731 respectively. The activation energies under oxygen environment were higher, it was 106 and 118 kJ/mole. The regression coefficient (R2) under oxygen environment was 0.9987 and 0.99883 for above sample sequence.
- Published
- 2018
17. Numerical analysis on the influential factors of coal gasification performance in two-stage entrained flow gasifier
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Kaleemullah Memon, Imran Nazir Unar, Sunel Kumar, Rasool Bux Mahar, YiJun Jia, Umair Sultan, Lijun Wang, Mujahid Ali, and Rundong Li
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Maximum temperature ,Materials science ,Wood gas generator ,Waste management ,business.industry ,020209 energy ,Flow (psychology) ,Analytical chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,Oxygen ,Industrial and Manufacturing Engineering ,020401 chemical engineering ,chemistry ,0202 electrical engineering, electronic engineering, information engineering ,Coal gasification ,Coal ,Stage (hydrology) ,0204 chemical engineering ,business ,Cfd software - Abstract
In this study 2D numerical simulation for two-stage entrained flow dry feed coal gasification performance was developed. The detailed operational characteristics of O/C distribution between the two stages of the gasifier were examined in standard CFD software FLUENT®14 to analyze their effects on the gasification performance. Furthermore the different reaction mechanisms were investigated for validation of the model with experimental results. The results show that H 2 and CO composition at the exit of gasifier are increased at O/C ratio 0.8 as compared to other simulation cases, and the temperature gradually decreases from 2nd injection level because of water-shift reaction. Maximum CO% was observed when 40% of oxygen injected at the lower level, overall range of H 2 % at the exit of gasifier was 10–45% but maximum H 2 % was found when 50% O 2 % and 30% of coal injected at a lower level. The maximum temperature about 2300 K when 40% O 2 and 40% of coal was injected at a lower level. Overall optimized results for CO, H 2 , and minimum CO 2 formation was observed when 60% O 2 and 40% of coal was injected at a lower level of the gasifier. The gasification performance can be controlled with the optimized coal/oxidant distribution between the stages.
- Published
- 2017
18. Numerical Study of Coal Composition Effects on the Performance of Gasification Through Computational Fluid Dynamic
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Rasool Bux Mahar, Shaheen Aziz, Imran Nazir Unar, Zulfiqar Ali Bhatti, Ghulamullah Maitlo, and Suhail Ahmed Soomro
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business.industry ,020209 energy ,General Chemical Engineering ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,0202 electrical engineering, electronic engineering, information engineering ,Environmental science ,Composition (visual arts) ,Coal ,business ,Process engineering ,0105 earth and related environmental sciences ,Syngas - Abstract
Pakistan is very rich in coal reserves specifically after exploration of Thar coal reserves. At the same time country is facing energy crises due to shortage or unavailability of sustainable fuel supply at a cheaper rate. One potential solution is coal gasification which gives clean synthetic gas usually called syngas for use as an alternative fuel source for electricity production at a cheaper rate as well as a source of recovering different chemicals used as basic raw materials in other industries. Numerical simulations have been performed in this work for the gasification process of indigenous coal on a 2D computational fluid dynamic (CFD) model of downdraft entrained-flow gasifier using commercial CFD software FLUENT®6.3.26. Navier-stokes equations along with transport equations for species have been solved using eddy-dissipation combustion model. The compositions of indigenous coals (Thar, Lakhra, and Sonda) were used in simulations as gasification feedstock. Rich oxidant conditions 95 % O2 and 5 % N2 were set for gasification. The gasification performance was studied by comparing efficiencies of gasification and quality of syngas produced for three types of coal feedings. The temperature and pressure profiles inside the gasifier were also studied. From simulation results, the great influence of coal composition was observed in the performance of gasification. Lakhra coal produced syngas with a maximum heating value of 20.55 MJ/kg whereas sonda coal produced syngas with a minimum heating value of 17.96 MJ/kg.
- Published
- 2019
19. Estimation of Power Production Potential from Natural Gas Pressure Reduction Stations in Pakistan Using ASPEN HYSYS
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Imran Nazir Unar, Aziza Aftab, and Masroor Abro
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lcsh:T ,lcsh:TA1-2040 ,lcsh:Q ,Pressure into Power ,Turbo Expanders ,Natural Gas ,lcsh:Engineering (General). Civil engineering (General) ,lcsh:Science ,lcsh:Technology ,Sales Metering Station - Abstract
Pakistan is a gas rich but power poor country. It consumes approximately 1, 559 Billion cubic feet of natural gas annually. Gas is transported around the country in a system of pressurized transmission pipelines under a pressure range of 600-1000 psig exclusively operated by two state owned companies i.e. SNGPL (Sui Northern Gas Pipelines Limited) and SSGCL (Sui Southern Gas Company Limited). The gas is distributed by reducing from the transmission pressure into distribution pressure up to maximum level of 150 psig at the city gate stations normally called SMS (Sales Metering Station). As a normal practice gas pressure reduction at those SMSs is accomplished in pressure regulators (PCVs or in throttle valves) where isenthalpic expansion takes place without producing any energy. Pressure potential of natural gas is an untapped energy resource which is currently wasted by its throttling. This pressure reduction at SMS (pressure drop through SMS) may also be achieved by expansion of natural gas in TE, which converts its pressure into the mechanical energy, which can be transmitted any loading device for example electric generator. The aim of present paper is to explore the expected power production potential of various Sales Metering Stations of SSGCL company in Pakistan. The model of sales metering station was developed in a standard flow sheeting software Aspen HYSYS®7.1 to calculate power and study other parameters when an expansion turbine is used instead of throttling valves. It was observed from the simulation results that a significant power (more than 140 KW) can be produced at pressure reducing stations of SSGC network with gas flows more than 2.2 MMSCFD and pressure ration more than 1.3.
- Published
- 2015
20. Determination of Arsenic and Health Risk Assessment in the Ground Water of Sindh, Pakistan
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Zulifqar Ali Bhatti, Muhammad Yar Khuhawar, Khadija Qureshi, Inamullah Bhatti, Imran Nazir Unar, and Unar, Mukhtiar Ali Unar
- Subjects
Sindh ,Health risk assessment ,lcsh:T ,[SPI] Engineering Sciences [physics] ,chemistry.chemical_element ,Atomic Absorption Spectrometer ,lcsh:Technology ,Arsenic ,River Indus ,chemistry ,lcsh:TA1-2040 ,Groundwater pollution ,Health Risk Assessment ,Environmental science ,lcsh:Q ,Water quality ,lcsh:Engineering (General). Civil engineering (General) ,lcsh:Science ,General Agricultural and Biological Sciences ,Risk assessment ,Water pollution ,Water resource management ,Groundwater - Abstract
As (Arsenic) is one of the lethal element present at the various locations of the world, putting human beings in danger by polluting the water. Arsenic Kit and atomic absorption spectrometer were used to determine As in ground water of Sindh province, Pakistan. Twenty-Four (24) districts both on the left and right bank of RI (River Indus) were analyzed. It was observed from the results that highest As concentration 200 ppb (parts per billion) i.e. above the WHO (World Health Organization) limit (10 ppb) was observed in Sakrand, district Shaheed Benazirabad followed by Hala, Matairi, TMK (Tando Mohammad Khan) and Nasarpur regions. It was further found that ground water of regions on the left bank of RIwas more contaminated than the right bank. Contour map was created using OriginPro and coordinate systems to highlight the elevated arsenic in the studied area. HRA (Health Risk Assessment) of these areas was carried out to calculate EDI (Estimated Daily Intake), TQH (Target Hazard Quotient) and CR (Cancer Risk). 45% of the total ground water samples analyzed were above the permissible limit for As in water and mostly these are located on the left bank of RI. The local wells in Sindh have never been tested for metal concentration former to use. These results provide baselines for researchers, NGO's (Non-Governmental Organizations) and government to apply arsenic treatment technologies in those areas.
- Published
- 2017
21. Numerical simulations for the coal/oxidant distribution effects between two-stages for multi opposite burners (MOB) gasifier
- Author
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Rasool Bux Mahar, Abdul Ghani Pathan, Rundong Li, Lijun Wang, M. Aslam Uqaili, and Imran Nazir Unar
- Subjects
Wood gas generator ,Renewable Energy, Sustainability and the Environment ,business.industry ,Chemistry ,Turbulence ,Nozzle ,Flow (psychology) ,Environmental engineering ,Energy Engineering and Power Technology ,Mechanics ,Fuel Technology ,Nuclear Energy and Engineering ,Coal gasification ,Coal ,Char ,business ,Syngas - Abstract
A 3D CFD model for two-stage entrained flow dry feed coal gasifier with multi opposite burners (MOB) has been developed in this paper. At each stage two opposite nozzles are impinging whereas the two other opposite nozzles are slightly tangential. Various numerical simulations were carried out in standard CFD software to investigate the impacts of coal and oxidant distributions between the two stages of the gasifier. Chemical process was described by Finite Rate/Eddy Dissipation model. Heterogeneous and homogeneous reactions were defined using the published kinetic data and realizable k–e turbulent model was used to solve the turbulence equations. Gas–solid interaction was defined by Euler–Lagrangian frame work. Different reaction mechanism were investigated first for the validation of the model from published experimental results. Then further investigations were made through the validated model for important parameters like species concentrations in syngas, char conversion, maximum inside temperature and syngas exit temperature. The analysis of the results from various simulated cases shows that coal/oxidant distribution between the stages has great influence on the overall performance of gasifier. The maximum char conversion was found 99.79% with coal 60% and oxygen 50% of upper level of injection. The minimum char conversion was observed 95.45% at 30% coal with 40% oxygen at same level. In general with oxygen and coal above or equal to 50% of total at upper injection level has shown an optimized performance.
- Published
- 2014
22. Numerical Simulation of Ethanol Production for Different Carbon Sources Using Thermotolerant Kluyveromyces Marxianus
- Author
-
Irshad Ali Gopang, Mohammad Siddique, Hidayatullah Mahar, Abdul Sattar Jatoi, Imran Nazir Unar, and Makhdoom Naeem
- Subjects
Sucrose ,Ethanol ,biology ,chemistry.chemical_element ,Industrial fermentation ,biology.organism_classification ,Pulp and paper industry ,chemistry.chemical_compound ,chemistry ,Kluyveromyces marxianus ,Yield (chemistry) ,Ethanol fuel ,Fermentation ,Carbon - Abstract
During process of fermentation a variety of parameters effect on ethanol production, current work focusses to investigate the effect of different carbon sources on ethanol production using numerical simulation. The fermentation process was carried out using microprocessor-controlled fermenter in which different types of carbon sources were studied like glucose, sucrose and molasses from 10 % to 15% of range. The model proposed by Monod was found to be more appropriate for describing the batch growth and ethanol production using kluyveromyces marxianus. The maximum yield of ethanol production took place using 15 % molasses as carbon source. The maximum ethanol production (76 g/l) was observed at 15% molasses, as for sucrose and glucose are concerned it gives lower value of ethanol production up to 73g/l by keeping other operational parameter under optimized condition such are 35oC, 300rpm, 0.2vvm/l and pH5.5. Approximately same results were achieved by using experimental data and model execution.
- Published
- 2018
23. Effect of Various Additives on the Physical Properties of Polyvinylchloride Resin
- Author
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Imran Nazir Unar, Suhail Ahmed Soomro, and Shaheen Aziz
- Subjects
lcsh:GE1-350 ,lcsh:QD71-142 ,Polyvinylchloride ,Additives ,lcsh:Analytical chemistry ,Physical properties ,Resin ,lcsh:Environmental sciences - Abstract
The compounding of Polyvinylchloride (PVC) with some additives was studied for the enhancement of physical and mechanical properties. Two categories of formulations (un-plasticized and plasticized PVC) were prepared with PVC (K value ranging from 60 to 70) taking as base polymer. Different additives generally categorized as plasticizers, fillers, stabilizers, pigments and processing aids, were mixed in the standard concentration unit “parts per hundred resins (phr)” with base polymer. Cable compound and shoe compound were prepared in plasticized-PVC category containing mainly plasticizing additives like diisooctyl phthalate (DIOP) (40 phr) and epoxidized soybean oil (2-3 phr) with general plasticizer (50-80 phr) respectively. Whereas the rigid pipe and sheet compounds were prepared as un-plasticized PVC category containing different fillers/stabilizers like tribasic lead sulphate (6 phr), lead stearate (1 phr), glyceryl monostearate (0.4 phr) in rigid pipe and butylin mercaptides (2-2.5 phr), fatty alcohol and fatty acid ester (0.5-0.8 phr) in rigid sheet compound. Experimental investigation was carried out for analyzing the mechanical properties like tensile strength, elongation at break, hardness and physical property i.e. specific gravity for the compounded samples. An appreciable increase was observed in tensile strength from 460 Kg/cm2 (base PVC-polymer) to a range of 550 Kg/cm2 for un-plasticized PVC compounds (rigid PVC-pipe and sheet) with little increase in elongation at break from 56% (base polymer) to 124.33% and 150% (for Pipe and Sheet compounds respectively). On the other side the elongation at break for plasticized PVC compounds was increased from 56% to 250.67% (for cable compound) and 351.33% (for shoe compound), where as the tensile strength was decreased from 460 Kg/cm2 to 150.33 Kg/cm2 (for cable compound) and 120.33 Kg/cm2 (for shoe compound). The hardness (shore A, D) was increased from 40 to 80 for all the compounds except shoe compound with hardness of 65.33. The impact of plasticizers was found in direct proportion on elongation at break but having inverse proportion on tensile strength.
- Published
- 2010
24. Value-Added Product Recovery from Banana Plant Waste: A Sustainable Way for Development
- Author
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Suhail Ahmed Soomro, Imran Nazir Unar, Shaheen Aziz, and Khan M. Qureshi
- Subjects
chemistry.chemical_classification ,Horticulture ,Hydrolysis ,Chemistry ,Cellulosic ethanol ,Enzymatic hydrolysis ,food and beverages ,Ethanol fuel ,Fermentation ,Acid hydrolysis ,Bagasse ,Pulp and paper industry ,Reducing sugar - Abstract
Pakistan being an agriculture country is enriched with abundance of biomass residues from agricultural crops such as wheat straw, rice husk, bagasse, banana plant, etc. that may be used for resources recovery. The banana plant is one of the potential cellulosic material like cotton crop, wood, etc., obtained from agricultural land. Development in the area of bio-conversion offers a cheap and safe method of not only disposal of agricultural residues but may also be used for the production of product, like, ethanol. Ethanol production from cellulosic material is a two stage process. Initially, the cellulosic material is converted to reducing sugar by acid hydrolysis or enzymatic hydrolysis and afterward, production of ethanol by fermentation process. The current work focuses on the optimization of acid hydrolysis and fermentation using Sacchromyces cerevisiae yeast. In the current study, process conditions for acid hydrolysis, i.e., particle size, reaction time, shaking speed, temperature and concentration of acid were studied in addition to fermentation process optimization. In acid hydrolysis, samples of various particle sizes, i.e., 26, 28, 30, 40, 50, and 100 μm, were used. It was found that reduction in particle size enhances the conversion of reducing sugars from banana plant. The optimized conditions for hydrolysis were found to be shaking time 2 h, temperature 80°C, shaking intensity 90 rpm, and solid–liquid ratio 50 g in 300 ml of H2SO4. With 100-μm particle size, optimum yield of Brix (reducing sugar) was obtained (21–24% per 300 ml). pH was adjusted in the range of 4.5–5.2. For the production of ethanol, aerobic fermentation was carried out using S. cerevisiae yeast species. The fermentation reaction was carried out in a 300-ml conical flask. Optimum yield was obtained at 31°C, residence time 8 h, and when shaken at 80 rpm.
- Published
- 2011
25. A Promising Technology of Pressure into Power: A Case Study of Pressure into Power Approach in Gas Transmission Lines in Pakistan
- Author
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Shaheen Aziz, Imran Nazir Unar, Suhail Ahmed Soomro, Abdul Rehman Memon, and Khan M. Qureshi
- Subjects
Upstream (petroleum industry) ,Overall pressure ratio ,Engineering ,Electricity generation ,Petroleum engineering ,business.industry ,Natural gas ,Fossil fuel ,Electric power ,business ,Energy source ,Downstream (petroleum industry) - Abstract
Pakistan is gas rich but power poor country. Conventional approach is always directed toward power plants using fossil fuel. Some trials have also taken place demonstrating wind and other nontraditional energy source for generating electricity. A pragmatic and feasible unexploited resource is the potential energy from high-pressure natural gas. Currently, this energy is being wasted at gas pressure reducing stations in Pakistan. At present there are two integrated gas companies (transmission and distribution), i.e., Sui Southern Gas Company Limited (SNGPL) and Sui Northern Gas Pipelines Limited (SSGCL). The gas is transmitted through the transmission pipelines in the pressure ranges of 800–1,000 psig. The gas is distributed by reducing from the transmission pressure into distribution pressure up to a maximum level of 150 psig at the city gate stations normally called “sales metering station (SMS).” There are almost more than 200 SMSs in SNGPL and SSGCL. This study highlights real possibilities to utilize the energy lost in gas reducing stations (SMSs) as a source of electrical power. The present study shows that with average pressure ratio (ratio of upstream to downstream pressure) of 10 and average gas flow of 35 MMSCFD from any gas metering station, more than 2 MWe power could be generated without consumption of any fuel.
- Published
- 2011
26. Sustainable Development Indicators for Energy in Pakistan
- Author
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Imran Nazir Unar and Abdul Khalique Ansari
- Subjects
Sustainable development ,Economic growth ,Electricity generation ,Geography ,Natural resource economics ,business.industry ,Energy (esotericism) ,Sustainability ,Energy indicators ,Brundtland Commission ,Electricity ,business ,Gross domestic product - Abstract
The strong challenges of sustainable development are as diversified and complex as the human societies and natural ecosystems around the world. Sustainable development requires the participation of diverse stack holders, with the idea of reconciling different and sometimes opposing values and goals toward a coordination of mutual action to achieve required goals. Energy sector issues and developments continued to severely constrain Pakistan’s economy in 2009–2010. Against a backdrop of a sharp increase in the international price of oil through the calendar year 2009, which put enormous upward pressure on the cost structure in the power generation (and transport) sector, in particular, large domestic supply shortages of electricity and gas occurred. Lower accumulation of water reserves in dams compounded the severity. The cumulative effect of the energy crisis on the economy is estimated at upward of 2% of gross domestic product (GDP) during 2009–2010 alone. Brundtland Commission and others provide the background for the approach we have chosen to structure the indicators. Sustainability indicators are generally designed to illustrate the economic, environmental, and social dimensions of sustainable development. Policymakers need methods for measuring and assessing the current and future effects of energy use on human health, human society, air, soil, and water. Energy indicators for sustainable development: guidelines and methodologies, IAEA (Energy indicators for sustainable development: guidelines and methodologies, Vienna, 2005) are focused here. Some guidelines are recommended for the sustainable development of energy in Pakistan.
- Published
- 2011
27. Environmental Impact of Untreated Effluents from Sugar Industry: A Case Study
- Author
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Shaheen Aziz, Suhail Ahmed Soomro, Abdul Rehman Memon, and Imran Nazir Unar
- Subjects
Pollution ,Engineering ,Waste management ,Wastewater ,business.industry ,media_common.quotation_subject ,Sugar industry ,Environmental impact assessment ,Sugar ,business ,Effluent ,media_common - Abstract
Sugar industry, being the major consumer of water, discharges its effluents into the outside environment mostly as untreated. However, besides knowing about the pollution strength of these effluents, knowledge about the mode of disposal of these effluents into the surroundings is also crucial. Thus, an intensive investigation was carried out to know the disposal patterns adopted by three selected sugar mills, namely, Habib Sugar Mills, Nawabshah, Matiari Sugar Mills, Matiari, and Fauji Sugar Mills, Tando Mohammad Khan, along with the obvious problems people were facing as a result. The study concluded that the disposal of untreated effluents into the surroundings had a negative impact on the resources such as land and water (both surface and ground) in particular and on the health of people and their livestock in general.
- Published
- 2011
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