Showing items 1 - 20 of 33

A comparative study of volatile organic compounds abatement

- Muzenda, Edison, Belaid, Mohamed

A review of the equations of state and their applicability in phase equilibrium modeling

- Ramdharee, Sashay, Muzenda, Edison, Belaid, Mohamed

  • 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.
  • Full Text:

A study of the variables in the optimisation of a platinum precipitation process

- Phetla, Tebogo, Muzenda, Edison, Belaid, Mohamed

  • Authors: Phetla, Tebogo , Muzenda, Edison , Belaid, Mohamed
  • Date: 2010
  • Subjects: Platinum Group Metals (PGM) , Platinum precipitation
  • Type: Article
  • Identifier: uj:4700 , http://hdl.handle.net/10210/10936
  • Description: This study investigated possible ways to improve the efficiency of the platinum precipitation process using ammonium chloride by reducing the platinum content reporting to the effluent. The ore treated consist of five platinum group metals namely, ruthenium, rhodium, iridium, platinum, palladium and a precious metal gold. Gold, ruthenium, rhodium and iridium were extracted prior the platinum precipitation process. Temperature, reducing agent, flow rate and potential difference were the variables controlled to determine the operation conditions for optimum platinum precipitation efficiency. Hydrogen peroxide was added as the oxidizing agent at the temperature of 85-90oC and potential difference of 700-850mV was the variable used to check the oxidizing state of platinum. The platinum was further purified at temperature between 60-65oC, potential difference above 700 mV, ammonium chloride of 200 l, and at these conditions the platinum content reporting to the effluent was reduced to less than 300ppm, resulting in optimum platinum precipitation efficiency and purity of 99.9%.
  • Full Text:

Alkenes - ester polymeric solvents thermodynamic interactions - part 2

- Scheepers, Jacques J., Muzenda, Edison, Belaid, Mohamed

  • Authors: Scheepers, Jacques J. , Muzenda, Edison , Belaid, Mohamed
  • Date: 2012
  • Subjects: Activity coefficients , Esters , Alkenes , Thermodynamics
  • Type: Article
  • Identifier: uj:5341 , http://hdl.handle.net/10210/9581
  • Description: This paper is a continuation of our work reported previously [1] on the interaction between ester solvents and alkene volatile organic compounds (VOCs). The interactions were presented inform of infinite dilution activity coefficients. A Microsoft Excel spreadsheet for the modified UNIFAC Dortmund group contribution method [2] was designed and used in computing the required phase equilibrium. The size of the solvent molecule (biodiesel) relative to the VOC molecule influenced the thermodynamic interactions. The degree of ester (biodiesel) bond saturation influenced the ease in which cyclic VOCs interacted with the solvent compared to their straight chain counterparts. The location of branches such as methyl branches in relation to the double-bonded carbons had an impact on the predicted infinite dilution activity coefficients.
  • Full Text:

An investigation into the effect of temperature on the leaching of copper-matte

- Muzenda, Edison, Ramatsa, I.M., Ntuli, Freeman, Belaid, Mohamed, Tshwabi, P.M.

  • Authors: Muzenda, Edison , Ramatsa, I.M. , Ntuli, Freeman , Belaid, Mohamed , Tshwabi, P.M.
  • Date: 2011
  • Subjects: Coppermatte leaching - Effect of temperature , Leaching - Effect of temperature
  • Type: Article
  • Identifier: uj:4703 , http://hdl.handle.net/10210/10944
  • Description: A study was carried out to determine the influence of the temperature and the reaction involved on the leaching of coppermatte. Copper (Cu) bearing matte from Impala Refinery (Pty) Ltd was used in the investigation. The experiments were conducted in a leaching cell submerged in a water bath, with ammonia concentrations (leaching solution) of 3.0M, temperature of 50°C, 60°C and 70°C, pH of 11 and for a time period of 130 minutes. Leaching tests indicated that Cu recovery increased in the temperature range 50°C - 60°C, however at a temperature of 70°C Cu recovery decreases because of cementation process as nickel displace copper. The shrinking core model was used to determine if the leaching process was diffusion controlled, or chemical controlled, or even mixed controlled. It was found that the leaching process could not be determined using the shrinking core model due to the cementation process of Cu. It was concluded that an increase in temperature results in an increase in the Cu recovery however the temperature should not be too high as cementation process increase with increasing temperature.
  • Full Text:

Analysis of the biogas productivity from dry anaerobic digestion of organic fraction of municipal solid waste

- Matheri, Anthony Njuguna, Sethunya, Vuiswa Lucia, Belaid, Mohamed, Muzenda, Edison, Ntuli, Freeman

Biochemical methane potential analysis using cow dung, chicken manure and pig manure under mesophilic conditions

- Belaid, Mohamed, Matheri, Anthony Njuguna, Mdluli, Nomkhosi Princess, Muzenda, Edison

  • Authors: Belaid, Mohamed , Matheri, Anthony Njuguna , Mdluli, Nomkhosi Princess , Muzenda, Edison
  • Date: 2019
  • Subjects: Anaerobic digestion , Mono-digestion , Co-digestion
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/403895 , uj:33863 , Citation: Belaid, M. et al. 2019. Biochemical methane potential analysis using cow dung, chicken manure and pig manure under mesophilic conditions.
  • Description: Abstract: In this study, we compared methane production by anaerobic mono-digestion and co-digestion of cow dung, chicken manure and pig manure under mesophilic conditions at the temperature of 37 0 C using a ratio of 1:1. C/N ratio, pH, VS/TS and sulphur content were the parameters investigated. Results indicated that co-digesting of cow dung; pig manure and chicken manure enhanced biogas production and methane content. The results also imply that pig manure cannot be used alone to produce methane as it produced low methane. Chicken manure produced more on the first day (272 Nml) compared to pig manure (257.4 Nml) and cow dung (80.5 Nml). On the ninth day, chicken produced 884 .9 Nml and then on the tenth day it went up again to 1095.6 Nml, reached its peak on day 13 and stopped, chicken yielded better results compared to the cow dung and pig manure because chicken had a higher VS/TS percent which is desirable for methane production. Pig manure started producing methane on the first day which was 257.4 Nml and stopped on the second day with the volume of 262.3 Nml. Pig manure showed poor results compared to cow dung and chicken manure.
  • Full Text:

Characterization of effluent from textile wet finishing operations

- Ntuli, Freeman, Ikhu-Omoregbe, Daniel, Kuipa, Pardon K., Muzenda, Edison, Belaid, Mohamed

Diisononyl phthalate – organics interactions : a phase equilibrium study using modified UNIFAC models

- Pheko, Given T, Muzenda, Edison, Belaid, Mohamed, Mateescu, Corina

  • Authors: Pheko, Given T , Muzenda, Edison , Belaid, Mohamed , Mateescu, Corina
  • Date: 2013
  • Subjects: Phase equilibrium , Volatile organic compounds , Diisononyl phthalate , Absorption abatement
  • Type: Article
  • Identifier: uj:4857 , http://hdl.handle.net/10210/12533
  • Description: Volatile organic compounds (VOCs) are a series of organic compounds that readily vaporize at room temperature. When emitted into the environment can affect climate change and plants growth, and cause long term human health risks. Absorption abatement technique has been the most preferred to reduce VOCs from contaminated gaseous streams, hence the need for a polymeric solvent with a greater affinity for end-pipe inventory. This phase equilibrium study investigated the ability of diisononyl phthalate (DINP) as an absorbent to 80 selected VOCs at infinite dilution. The solvent-solute(s) interactions were studied using modified UNIFAC Lyngby and Dortmund group contribution methods, with the latter being consistent and reliable, as its results are related to literature. Alkanes, alkanes, aldehydes and cyclo-alkanes with shorter carbon-chain length are highly soluble in DINP, with their solubility decreasing with increasing molecular weight or size, at infinite dilution. Alkynes, ketones, alcohols and carboxylic acids are less soluble in DINP, as a result of their dominating polarity compared to the DINP non-polarity structure. However, results could be improved with further studies and publication of solvent-solute(s) sub-groups interaction parameters, and thus further development of modified UNIFAC Lyngby model. DINP is a good absorbent for short-chained non-polar VOCs.
  • Full Text:

Estimating the absorption of volatile organic compounds in four biodiesels using the Unifac procedure

- Mateescu, Corina M., Muzenda, Edison, Belaid, Mohamed, Abdulkareem, Saka, Afolabi, Ayo S.

  • Authors: Mateescu, Corina M. , Muzenda, Edison , Belaid, Mohamed , Abdulkareem, Saka , Afolabi, Ayo S.
  • Date: 2011
  • Subjects: Biodiesel , Volatile organic compounds , Absorption
  • Type: Article
  • Identifier: http://ujcontent.uj.ac.za8080/10210/363185 , uj:4696 , http://hdl.handle.net/10210/10760
  • Description: This work considered the thermodynamic feasibility of scrubbing volatile organic compounds into biodiesel in view of designing a gas treatment process with this absorbent. A detailed vapour – liquid equilibrium investigation was performed using the original UNIFAC group contribution method. The four biodiesels studied in this work are methyl oleate, methyl palmitate, methyl linolenate and ethyl stearate. The original UNIFAC procedure was used to estimate the infinite dilution activity coefficients of 13 selected volatile organic compounds in the biodiesels. The calculations were done at the VOC mole fraction of 9.213x10-8. Ethyl stearate gave the most favourable phase equilibrium. A close agreement was found between the infinite dilution activity coefficient of toluene found in this work and those reported in literature. Thermodynamic models can efficiently be used to calculate vast amount of phase equilibrium behaviour using limited number of experimental data.
  • Full Text:

Feasibility study for a castor oil extraction plant in South Africa

- Belaid, Mohamed, Muzenda, Edison, Mitilene, Getrude, Mollagee, Mansoor

  • Authors: Belaid, Mohamed , Muzenda, Edison , Mitilene, Getrude , Mollagee, Mansoor
  • Date: 2011
  • Subjects: Castor oil extraction
  • Type: Article
  • Identifier: uj:4706 , http://hdl.handle.net/10210/10950
  • Description: A feasibility study for the design and construction of a pilot plant for the extraction of castor oil in South Africa was conducted. The study emphasized the four critical aspects of project feasibility analysis, namely technical, financial, market and managerial aspects. The technical aspect involved research on existing oil extraction technologies, namely: mechanical pressing and solvent extraction, as well as assessment of the proposed production site for both short and long term viability of the project. The site is on the outskirts of Nkomazi village in the Mpumalanga province, where connections for water and electricity are currently underway, potential raw material supply proves to be reliable since the province is known for its commercial farming. The managerial aspect was evaluated based on the fact that the current producer of castor oil will be fully involved in the project while receiving training and technical assistance from Sasol Technology, the TSC and SEDA. Market and financial aspects were evaluated and the project was considered financially viable with a Net Present Value (NPV) of R2 731 687 and an Internal Rate of Return (IRR) of 18% at an annual interest rate of 10.5%. The payback time is 6years for analysis over the first 10 years with a net income of R1 971 000 in the first year. The project was thus found to be feasible with high chance of success while contributing to socio-economic development. It was recommended for lab tests to be conducted to establish process kinetics that would be used in the initial design of the plant.
  • Full Text:

Glycerol - a viable solvent for absorption of highly polar solutes II : behaviour of molecular interactions

- Scheepers, Jacques J., Muzenda, Edison, Belaid, Mohamed

  • Authors: Scheepers, Jacques J. , Muzenda, Edison , Belaid, Mohamed
  • Date: 2015
  • Subjects: Activity coefficients , Glycerol , Solubility , Volatile organic compounds , Scrubbing solvents
  • Type: Article
  • Identifier: uj:5054 , http://hdl.handle.net/10210/13593
  • Description: This work focused on the potential of glycerol as a scrubbing solvent for stripping of highly polar volatile organic compounds (VOCs) from industrial waste gas streams. Results for glycerol interactions were compared to those of water. Solubility predictions in the form of infinite dilution activity coefficients were made using the Modified UNIFAC Dortmund group contribution model, which was set up on a Microsoft Excel spreadsheet specifically designed for this purpose. Activity coefficients for VOCs in water and glycerol (highly polar solvents) increased with an increase in the length of the VOC solute nonpolar tail. Furthermore, activity coefficients decreased with an increase in the degree of branching of the VOC solute. The results show that low chain length highly polar alcohol, ketone, organic acid and aldehyde solutes are very soluble in glycerol. Diols, dicarbonyl aldehydes, some ketone derivatives and the ethanolamines also show good solubility. Highly polar diesters and ester derivatives are less soluble in glycerol and water. This study has found glycerol to be a better scrubbing solvent than water in treating highly polar VOCs. However it is possible that the standard method of building up the glycerol molecule in the UNIFAC may result in under-predictions of activity coefficients and thus special group interaction parameters for glycerol are required.
  • Full Text:

Influence of structure on fatty acid ester-alkane interactions

- Scheepers, Jacques J., Muzenda, Edison, Belaid, Mohamed

  • Authors: Scheepers, Jacques J. , Muzenda, Edison , Belaid, Mohamed
  • Date: 2012
  • Subjects: Absorption , Activity coefficients , Biodiesel , Esters , Volatile organic compounds
  • Type: Article
  • Identifier: uj:4671 , ISSN 978-988-19252-2-0 , http://hdl.handle.net/10210/10436
  • Description: The activity coefficients of alkane structures in various types of fatty acid ester solvents was measured in order to determine the effect of bond interactions between these two chemical species. It is important to understand the mechanics of these interactions for absorber system design. Activity coefficients were determined by use of a Microsoft Excel spreadsheet designed for this purpose. It was determined that the length of the ester chain, as well as ester chain saturation had an impact on activity coefficients, in that saturated ester chains and longer ester chains yielded lower activity coefficients. Multiple branched cycloalkanes yielded lower activity coefficients than straight chain hydrocarbons and unbranched cycloalkanes. It was also noted that the location of the carboxyl group in the ester chain had no influence on activity coefficients.
  • Full Text:

Influence of temperature and molecular structure on organics-biodiesel interactions using group contribution methods

- Scheepers, Jacques J., Muzenda, Edison, Belaid, Mohamed

  • Authors: Scheepers, Jacques J. , Muzenda, Edison , Belaid, Mohamed
  • Date: 2012
  • Subjects: Group contribution method , Phase equilibrium , Solubility , Volatile organic compounds , Absorption , Activity coefficients
  • Type: Article
  • Identifier: uj:4672 , ISBN 978-93-82242-16-1 , http://hdl.handle.net/10210/10437
  • Description: Resulting from the trend of increasingly stringent environmental legislation, the drive to secure environmentally friendly absorption solvents has gained much impetus in recent times. In order to design and operate separation processes units, it is essential that the engineer has accurate and reliable knowledge of the phase equilibrium behaviour of the system in question. Since obtaining experimental data on the system can be time-consuming, the use of thermodynamic models is often useful in obtaining preliminary design and feasibility study information. This work examines the suitability of biodiesel (particularly the constituents methyl palmitate and methyl linolenate) as an absorbent solvent for the recovery of volatile organic compounds (VOCs) from waste process gas streams. In particular, activity coefficients were measured in the dilute region in an attempt to predict the effects of molecular structure and temperature on the solubility of the VOCs in the methyl esters under study. The group contribution methods UNIFAC and Modified UNIFAC Dortmund, set up on Microsoft Excel spreadsheets, were used to predict the required phase equilibrium at infinite dilution. The results obtaine
  • Full Text:

Intermolecular dynamics between aromatic compounds and ester polymeric solvents

- Scheepers, Jacques J., Muzenda, Edison, Belaid, Mohamed

  • Authors: Scheepers, Jacques J. , Muzenda, Edison , Belaid, Mohamed
  • Date: 2013
  • Subjects: Activity coefficients , Aromatic compounds , Solubility , Esters
  • Type: Article
  • Identifier: uj:4836 , http://hdl.handle.net/10210/12484
  • Description: This work focused on the interactions that occur between ester solvents and simple aromatic solutes. Solutes were selected from various functional groups in their simplest form, and predictions of activity coefficients at infinite dilution were made using the Modified UNIFAC Dortmund group contribution model. The model computation was set up on a Microsoft Excel spreadsheet specifically designed for this purpose. For polar aromatic solutes, solubility decreased with increase in size of the ester solvent molecule and the opposite was found to be true for non-polar solutes. For all aromatic/ ester solvent interactions there was a decrease in activity coefficients with an increase in the degree of ester unsaturation.
  • Full Text:

Mesophilic anaerobic co-digestion of cow dung, chicken droppings and grass clippings

- Matheri, Anthony Njuguna, Belaid, Mohamed, Seodigeng, Tumisang, Ngila, Catherine Jane, Mbohwa, Charles

Modelling the kinetic of biogas production from co-digestion of pig waste and grass clippings

- Matheri, Anthony Njuguna, Belaid, Mohamed, Seodigeng, Tumisang, Ngila, Catherine Jane

Multi-criteria analysis of different technologies for the bioenergy recovery from OFMSW

- Matheri, Anthony Njuguna, Mbohwa, Charles, Belaid, Mohamed, Seodigeng, Tumisang, Ngila, Jane Catherine

Optimization of Biogas Production from sewage sludge

- Belaid, Mohamed, Matheri, Anthony Njuguna, Lelosa, Itumeleng Constance, Muzenda, Edison, Ramatsa, Ishmael

Optimization of process parameters for castor oil production

- Muzenda, Edison, Kabuba, John, Mdletye, Philiswa, Belaid, Mohamed

  • Disclaimer
  • Privacy
  • Copyright
  • Contact