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A comparative review of waste tyre pyrolysis, gasification and liquefaction (PGL) processes

  • Authors: Muzenda, Edison
  • Date: 2014
  • Subjects: Pyrolysis , Gases - Liquefaction , Waste tyre pyrolysis , Waste tyres - Environmental aspects
  • Type: Article
  • Identifier: uj:5030 , http://hdl.handle.net/10210/13550
  • Description: This article reviews remedial waste tyre technologies as well as utilization for energy and material recovery. Application examples and scenarios are drawn from developing countries such as South Africa. Waste minimization and utilization technologies are required to address the growing waste tyre problem. Waste tyres cause a variety of environmental and health challenges as they are bulk and non-degradable. Potential solutions to address the waste tyre problem are pyrolysis, gasification and liquefaction (PGL) processes. Process conditions and potential products for each process are reviewed and discussed in this paper. An environmental impact assessment of PGL processes and potential remedial solutions are also presented. PGL processes have huge potential for business. However the success of any operation depends on several economic and environmental factors such as capital and operating costs, feed availability, permitting process and emission from these operations.
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A comparative study of volatile organic compounds abatement

A comparison of waste lubricating oil treatment techniques

A critical discussion of volatile organic compounds recovery techniques

A discussion of waste tyre utilization options

  • Authors: Muzenda, Edison
  • Date: 2014
  • Subjects: Waste tyre management , Waste tyre utilization
  • Type: Article
  • Identifier: uj:4783 , http://hdl.handle.net/10210/11966
  • Description: This paper communicates waste tyre management and utilization routes. Waste tyres can be utilized in various rubber applications such as in engineering and construction, environmental protection and agriculture. Energy and material recovery may also be achieved through thermal and thermochemical processes such as incineration and pyrolysis, gasification and liquefaction (PGL) process respectively. The social-economic and environmental benefit analysis of each treatment option is highlighted.
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A discussion on waste generation and management trends in South Africa

  • Authors: Muzenda, Edison
  • Date: 2014
  • Subjects: Waste management - South Africa , Solid waste management - South Africa , Integrated Industry Waste Tyre Management Plan
  • Type: Article
  • Identifier: uj:4762 , ISSN 2320–4087 , http://hdl.handle.net/10210/11871
  • Description: This paper, a continuation and expansion of the work of Muzenda et al, 2012 [1] looks at the management trends in South Africa. It focuses on waste classification, hierarchy, generation and management. The waste tyre problem in South Africa is also briefly discussed. Solid waste management is a growing environmental problem in developing countries such as South Africa. The increasing standard of living and economic growth results in challenges in the management of both general and hazardous waste. Landfill sites life spans have been reduced and hence the need for waste minimization, utilization and alternative disposal methods. Waste tyre management is challenge as they are non compactable and non-biodegradable. The REDISA Integrated Industry Waste Tyre Management Plan (IIWTMP) approved by Environmental Affairs Minister, Edna Molewa, and published in the Government Gazette [No. 35927] in November 2012 support and promote tyre recycling, providing the collection and depot infrastructure required to collect waste tyres from across the entire country and deliver them to approved recyclers. The objectives of this paper were achieved through a literature review and analysis.
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A multistage sulphidisation flotation procedure for a low grade malachite copper ore

  • Authors: Phetla, Tebogo P. , Muzenda, Edison
  • Date: 2010
  • Subjects: Sulphidisation , Copper oxide ore , Flotation
  • Type: Article
  • Identifier: uj:4707 , http://hdl.handle.net/10210/10951
  • Description: This study was carried out to develop a flotation procedure for an oxide copper ore from a Region in Central Africa for producing an 18% copper concentrate for downstream processing at maximum recovery from a 4% copper feed grade. The copper recoveries achieved from the test work were less than 50% despite changes in reagent conditions (multistage sulphidisation, use of RCA emulsion and mixture, use of AM 2, etc). The poor recoveries were attributed to the mineralogy of the ore from which copper silicates accounted for approximately 70% (mass) of the copper minerals in the ore. These can be complex and difficult to float using conventional flotation methods. Best results were obtained using basic sulphidisation procedures, a high flotation temperature and extended flotation residence time.
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A note on the dependence of volatile organic compounds specific retention volumes on temperature

  • Authors: Muzenda, Edison , Ntuli, Freeman
  • Date: 2011
  • Subjects: Volatile organic compounds , Gas liquid chromatography
  • Type: Article
  • Identifier: uj:6240 , http://hdl.handle.net/10210/8181
  • Description: This study investigated the influence of temperature on the specific retention volumes ( o g V ) of 13 volatile organic compounds (VOCs) in silicon oil as the liquid stationary phase using gas liquid chromatography (GLC). Temperature was varied from 303.15K to 423.15K to allow transport calculations for different seasons. Four PDMS polymers with average molecular weight ranging from 760 to 13 000 were used as solvents. Linear plots of log Vg against 1 T were obtained in all cases permitting predictions and interpolations to temperatures not studied here and also dependable enthalpies and entropies of solute transfer from the mobile phase to the stationary phase can be calculated. The specific retention volumes reported in this work are in agreement with literature for similar systems. Efforts were taken to ensure the best possible accuracy and trace the possible sources of error. We devised a gas liquid chromatographic system which secured a simple retention mechanism and showed reproducible solute retention over a long period of time.
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A review and discussion of waste tyre pyrolysis and derived products

  • Authors: Nkosi, Nhlanhla , Muzenda, Edison
  • Date: 2014
  • Subjects: Waste tyre pyrolysis
  • Type: Article
  • Identifier: uj:4782 , http://hdl.handle.net/10210/11965
  • Description: This paper reviews and discusses the waste tyre pyrolysis process and the applications of the derived products. The primary and secondary applications of oil, char, gas and steel wires are discussed. The paper also reviews the influence of operating parameters such as feed size, temperature and residence time. An analysis of the pyrolysis products market is also given. The study objectives were achieved through a triangulation procedure comprising of literature analysis, site visits and as well as personal and telephonic interviews. The paper concludes by discussing the successes and failures of the pyrolysis process.
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A review of biogas production optimization from grass silage

  • Authors: Muzenda, Edison , Sibiya, Noxolo
  • Date: 2014
  • Subjects: Biogas , Grass - Silage , Anaerobic digestion
  • Type: Article
  • Identifier: uj:5033 , http://hdl.handle.net/10210/13553
  • Description: Anaerobic digestion (AD) of organic materials offers an alternative source of renewable energy, as bio-methane has a potential to replace fossil fuels for energy production for heat and power, vehicular fuel and as well as valuable material recovery. In addition AD can address pollution problems by minimizing and utilizing biodegradable waste. This is a well-researched and technologically advanced technique with various successful small to large scale plants in the developed world. For developing countries, not much success has been reported due to operational and maintenance challenges, low biogas production and public perceptions among other several contributing factors. This paper reviews AD process optimization focusing on parameters such as temperature, pH, loading rate, hydraulic retention time and agitation. Several studies have shown optimum biogas production from grass in mesophilic, alkaline or neutral conditions at retention times of about 30 days. This review is the background and basis of our current work on optimizing biogas production from selected South African grass species.
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A review of biogas purification through chemical absorption

  • Authors: Muzenda, Edison , Maile, Ireen
  • Date: 2014
  • Subjects: Anaerobic digestion , Biogas purification , Chemical absorption
  • Type: Article
  • Identifier: uj:5041 , http://hdl.handle.net/10210/13561
  • Description: Biogas is an alternative source of energy which is produced by anaerobic digestion (AD) of waste materials. Biogas contains 50 -70% methane and 30-50% carbon dioxide as well as small a amounts of other gases with a calorific value of about 21-24 MJ/m3 . These trace components limit the usage of the biogas as they lower the calorific value of the gas and limit its commercialization. Hence, there is a need for purification and upgrading to meet specified application standards. The purification and upgrading processes can be classified into four major techniques which are absorption, adsorption, membrane separation and cryogenic separation. This review is focused on biogas enrichment through chemical absorption. This process involves amine washing with mono-,di- or tri-ethanolamine solutions, alkali washing with calcium oxide, calcium, potassium and sodium hydroxides, and synthesised ionic solutions of halide imidazolium ionic liquids. The regeneration of the spent chemicals for re-use will also be studied.
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A review of experimental scope, designs and methods from intermediate-fast pyrolysis of biomass

  • Authors: Charis, Gratitude , Danha, Gwiranai , Muzenda, Edison , Nkosi, Nhlanhla P.
  • Date: 2019
  • Subjects: Experimental , Ntermediate-fast , Pyrolysis
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/404768 , uj:33960 , Citation: Charis, G. et al. 2019. A review of experimental scope, designs and methods from intermediate-fast pyrolysis of biomass.
  • Description: Abstract: Intermediate and fast pyrolysis (IFP) for the recovery of bio-oil from organic matter have gained the attention of researchers in their attempt to increase the contribution of renewables into the energy mix. Current research has focused on equipment configuration and variables for higher yields of the oils; methods of upgrading the oils for compatibility with existing fuel infrastructure and engines, and various tests to characterize the products or test their applicability as fuels. This paper reviews the progress in experimental work around intermediate- fast pyrolysis (hot vapour residence~1-20s; moderate to high liquid yields) in the past twelve years. The review focuses on the experimental scope, equipment used, preparation of raw materials, experimental design and characterization of bio-oils. Experimental work covering actual applications of the oils are not covered in this review paper. The feedstocks mostly researched on in IFP were rice husks, followed by pinewood, Jatropha curcas cake and rapeseed respectively. Most IFP studies have been done on woody biomass (over 100 different feedstocks) due to their consistency, followed by agricultural residues then herbaceous energy crops. Lignocellulosics proved to be the veteran organic feedstocks (~95% of IFP) ahead of non- lignocellulosic biomass (~5%). The most applied technologies in recent years, were fluidized bed followed by the free fall reactors. For the experimental design, most papers reviewed used the simple single parameter method, while a few used the central composite rotatable design and full factorial design methods. The characterization tests mostly conducted on the oils were the pH, viscosity, Karl Fischer titration and calorific value.
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A review of polydimethylsiloxane - volatile organic compounds interactions

  • Authors: Muzenda, Edison
  • Date: 2012
  • Subjects: Polymers , Volatile organic compounds , Polydimethylsiloxane , Gas liquid chromatography
  • Type: Article
  • Identifier: uj:4682 , ISBN 978-93-82242-07-9 , http://hdl.handle.net/10210/10455
  • Description: This paper is a review on the interactions of certain volatile organic compounds with polydimethylsiloxane using the gas liquid chromatographic technique (GLC). The interactions reviewed here were studied in the form of specific retention volumes. Only single stationary phases were considered in this review. For similar systems, the retention data agrees very well. This review has shown that the GLC is a rapid and convenient method to obtain thermodynamic data for polymeric systems. This work is very useful in the determination of phase equilibrium in form of infinite dilution activity coefficients necessary for the design of absorption and stripping columns for the abatement of volatile organic compounds from contaminated air streams.
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A review of the equations of state and their applicability in phase equilibrium modeling

  • Authors: Ramdharee, Sashay , Muzenda, Edison , Belaid, Mohamed
  • Date: 2013
  • Subjects: Equations of state , Phase equilibrium modeling
  • Type: Article
  • Identifier: uj:4757 , http://hdl.handle.net/10210/11743
  • Description: This short paper reviews the equations of state and their application to phase equilibrium modeling. The strengths, weaknesses and applicability of these equations will be assessed. Our intention is to test the applicability of the Peng Robinson equation of state in the computation of thermodynamic interactions of volatile organic compounds and biodiesel. Thermodynamic models are very useful in phase equilibrium prediction as measurements are costly and time consuming.
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A review of waste lubricating grease management

  • Authors: Diphare, Motshumi J. , Pilusa, Jefrey , Muzenda, Edison , Mollagee, Mansoor
  • Date: 2014
  • Subjects: Waste lubricating grease , Waste management
  • Type: Article
  • Identifier: uj:4930 , http://hdl.handle.net/10210/13030
  • Description: This paper reviews the handling, disposal, treatment of waste lubricating grease as well as its environmental impact. Lubricants require careful disposal as they contain pollutants. In response to economic considerations and environmental protection, there is a growing trend of regeneration and reuse of waste lubricants. Accordingly, this work provides an overview on various ways of handling, disposal, treatment of waste grease and its associated environmental impacts. In addition to the fact that petroleum and crude oil are not inexhaustible resources, waste products from these resources present a hazard to human health and the environment. As such, proper management of waste lubricants is necessary to prevent the adverse environmental impacts. Efficient recycling of waste lubricants could help reduce environmental pollution.
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A review on Botswana coal potential from a pyrolysis and gasification perspective

A revisit and review of experimental variables affecting chromatographic organics - polydimethylsiloxane interactions

A revisit and review of experimental variables affecting chromatographic organics - polydimethylsiloxane interactions

A simple static headspace method for phase equilibrium measurement

A study of South African natural zeolites properties and applications

  • Authors: Diale, Palesa. P. , Muzenda, Edison , Zimba, Josephat
  • Date: 2011
  • Subjects: Zeolites - South Africa
  • Type: Article
  • Identifier: uj:6067 , ISSN 2078-0966 , http://hdl.handle.net/10210/10669
  • Description: The morphology and chemistry of natural zeolites, whose occurrence is ubiquitous to the South African provinces of Kwa-Zulu Natal (KZN) and Western Cape (WC), were studied using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray fluorescence (XRF) and the Brunauer-Emmett-Teller (BET) nitrogen adsorptiondesorption technique. The stability of these zeolites in varying pH conditions and their cation exchange capacity (CEC) was also investigated. The main mineral constituent of the natural zeolites was found to be clinoptilolite, with plagioclase, quartz and muscovite being the common impurities. The zeolite footprint was not altered after treatment with a hydrochloric (HCl) acid. The BET surface area ranged from 65.5 to 33.22 m2/g while the pore size ranged from 3 to 10 nm for the natural zeolites. These properties make them good prospective materials for application in biomedicines, environmental preservation and agriculture.
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