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:
- 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:
From UNIQUAC to modified UNIFAC Dortmund : a discussion
- Authors: Muzenda, Edison
- Date: 2013
- Subjects: Gibbs energy , Group contribution , Phase equilibrium , UNIFAC models
- Type: Article
- Identifier: uj:4868 , http://hdl.handle.net/10210/12544
- Description: This paper reviews and discusses the universal quasi – chemical theory and group contribution methods focusing on their application in phase equilibrium modeling and computation. The historical perspective, algorithm, strength, weaknesses and limitations are presented. The paper concludes with comparison of the performance of the various UNIFAC models.
- Full Text:
- Authors: Muzenda, Edison
- Date: 2013
- Subjects: Gibbs energy , Group contribution , Phase equilibrium , UNIFAC models
- Type: Article
- Identifier: uj:4868 , http://hdl.handle.net/10210/12544
- Description: This paper reviews and discusses the universal quasi – chemical theory and group contribution methods focusing on their application in phase equilibrium modeling and computation. The historical perspective, algorithm, strength, weaknesses and limitations are presented. The paper concludes with comparison of the performance of the various UNIFAC models.
- 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:
- 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:
Organics – biodiesel systems phase equilibrium computation : part 1
- Nkosi, Nhlanhla P., Mokoena, Phumzile, Muzenda, Edison, Belaid, Mohamed
- Authors: Nkosi, Nhlanhla P. , Mokoena, Phumzile , Muzenda, Edison , Belaid, Mohamed
- Date: 2011
- Subjects: Activity coefficient , Group contribution , Phase equilibrium , Solubility , Volatile organic compounds
- Type: Article
- Identifier: uj:4675 , http://hdl.handle.net/10210/10444
- Description: The group contribution concept can be applied in the estimation of thermodynamic properties of pure compounds and mixtures. The Modified UNIFAC (Dortmund) is a successful and well-known group contribution model for phase equilibria prediction. In this paper the application of this model to the phase equilibrium of biodiesel - volatile organic compounds systems was tested. Infinite dilution activity coefficients of 30 selected volatile organic compounds (VOCs) in methyl linoleate and methyl palmitate were estimated. The VOCs groups covered in the selection were alkanes, alkenes, alkynes, aromatics, ethers and ketones. The estimated phase equilibrium is favourable for the absorption of these organics into methyl linoleate. The solubility was found to decrease with increase in molecular weight of the VOCs in each group. Saturation was also found to have an effect on solubility. Experimental data are often not available, at least for preliminary design and feasibility studies of absorption processes, group contribution methods can be utilized to predict the required phase equilibria.
- Full Text:
- Authors: Nkosi, Nhlanhla P. , Mokoena, Phumzile , Muzenda, Edison , Belaid, Mohamed
- Date: 2011
- Subjects: Activity coefficient , Group contribution , Phase equilibrium , Solubility , Volatile organic compounds
- Type: Article
- Identifier: uj:4675 , http://hdl.handle.net/10210/10444
- Description: The group contribution concept can be applied in the estimation of thermodynamic properties of pure compounds and mixtures. The Modified UNIFAC (Dortmund) is a successful and well-known group contribution model for phase equilibria prediction. In this paper the application of this model to the phase equilibrium of biodiesel - volatile organic compounds systems was tested. Infinite dilution activity coefficients of 30 selected volatile organic compounds (VOCs) in methyl linoleate and methyl palmitate were estimated. The VOCs groups covered in the selection were alkanes, alkenes, alkynes, aromatics, ethers and ketones. The estimated phase equilibrium is favourable for the absorption of these organics into methyl linoleate. The solubility was found to decrease with increase in molecular weight of the VOCs in each group. Saturation was also found to have an effect on solubility. Experimental data are often not available, at least for preliminary design and feasibility studies of absorption processes, group contribution methods can be utilized to predict the required phase equilibria.
- Full Text:
Organics-biodiesel systems phase equilibrium computation : part 2
- Ntaka, Loyiso, Muzenda, Edison
- Authors: Ntaka, Loyiso , Muzenda, Edison
- Date: 2011
- Subjects: Activity coefficients , Phase equilibrium , Volatile organic compounds
- Type: Article
- Identifier: uj:6087 , http://hdl.handle.net/10210/10939
- Description: In part 1, the infinite dilution activity coefficients of 30 organics in methyl linoleate and methyl palmitate were reported. This work tested the application of Modified UNIFAC (Dortmund) as a molecular thermodynamic method in organic – polymer systems phase equilibrium estimation. Infinite dilution activity coefficients of 30 volatile organic compounds (VOCs) in methyl oleate and ethyl stearate were predicted using the Modified UNIFAC (Dortmund) procedure. The infinite dilution activity coefficients obtained in this study compare very well with literature findings. For example the calculated infinite dilution activity coefficients for benzene and toluene agree to about ±5% with those obtained from headspace and dynamic gas–liquid chromatographic measurements. biodiesel polymers were found to absorb ethers and aromatics better compared to other VOC family groups.
- Full Text:
- Authors: Ntaka, Loyiso , Muzenda, Edison
- Date: 2011
- Subjects: Activity coefficients , Phase equilibrium , Volatile organic compounds
- Type: Article
- Identifier: uj:6087 , http://hdl.handle.net/10210/10939
- Description: In part 1, the infinite dilution activity coefficients of 30 organics in methyl linoleate and methyl palmitate were reported. This work tested the application of Modified UNIFAC (Dortmund) as a molecular thermodynamic method in organic – polymer systems phase equilibrium estimation. Infinite dilution activity coefficients of 30 volatile organic compounds (VOCs) in methyl oleate and ethyl stearate were predicted using the Modified UNIFAC (Dortmund) procedure. The infinite dilution activity coefficients obtained in this study compare very well with literature findings. For example the calculated infinite dilution activity coefficients for benzene and toluene agree to about ±5% with those obtained from headspace and dynamic gas–liquid chromatographic measurements. biodiesel polymers were found to absorb ethers and aromatics better compared to other VOC family groups.
- Full Text:
Phase equilibrium of volatile organic compounds in polymeric solvents using group contribution methods
- Authors: Muzenda, Edison
- Date: 2010
- Subjects: Volatile organic compounds , Phase equilibrium , Glycol polymers , Biodiesel
- Type: Article
- Identifier: uj:4697 , http://hdl.handle.net/10210/10930
- Description: Group contribution methods such as the UNIFAC are of major interest to researchers and engineers involved synthesis, feasibility studies, design and optimization of separation processes as well as other applications of industrial use. Reliable knowledge of the phase equilibrium behavior is crucial for the prediction of the fate of the chemical in the environment and other applications. The objective of this study was to predict the solubility of selected volatile organic compounds (VOCs) in glycol polymers and biodiesel. Measurements can be expensive and time consuming, hence the need for thermodynamic models. The results obtained in this study for the infinite dilution activity coefficients compare very well those published in literature obtained through measurements. It is suggested that in preliminary design or feasibility studies of absorption systems for the abatement of volatile organic compounds, prediction procedures should be implemented while accurate fluid phase equilibrium data should be obtained from experiment.
- Full Text:
- Authors: Muzenda, Edison
- Date: 2010
- Subjects: Volatile organic compounds , Phase equilibrium , Glycol polymers , Biodiesel
- Type: Article
- Identifier: uj:4697 , http://hdl.handle.net/10210/10930
- Description: Group contribution methods such as the UNIFAC are of major interest to researchers and engineers involved synthesis, feasibility studies, design and optimization of separation processes as well as other applications of industrial use. Reliable knowledge of the phase equilibrium behavior is crucial for the prediction of the fate of the chemical in the environment and other applications. The objective of this study was to predict the solubility of selected volatile organic compounds (VOCs) in glycol polymers and biodiesel. Measurements can be expensive and time consuming, hence the need for thermodynamic models. The results obtained in this study for the infinite dilution activity coefficients compare very well those published in literature obtained through measurements. It is suggested that in preliminary design or feasibility studies of absorption systems for the abatement of volatile organic compounds, prediction procedures should be implemented while accurate fluid phase equilibrium data should be obtained from experiment.
- Full Text:
Phase equilibrium of volatile organic compounds in silicon oil using the UNIFAC procedure : an estimation
- Muzenda, Edison, Simate, Geoffrey S., Belaid, Mohamed, Ntuli, Freeman, Mollagee, Mansoor
- Authors: Muzenda, Edison , Simate, Geoffrey S. , Belaid, Mohamed , Ntuli, Freeman , Mollagee, Mansoor
- Date: 2011
- Subjects: Phase equilibrium , Thermodynamic models , Volatile organic compounds , Polydimethylsiloxane , Silicon oil
- Type: Article
- Identifier: uj:4699 , http://hdl.handle.net/10210/10934
- Description: This paper focuses on the phase equilibrium of volatile organic compounds in silicon oil chemically known as PDMS (polydimethylsiloxane) at infinite dilution. Measurements can be expensive and time consuming, hence the need for thermodynamic models which allow the calculation of the phase equilibrium behavior using a limited number of experimental data. The objective of this study was to predict infinite dilution activity coefficients of selected VOCs (volatile organic compounds) in PDMS using the Original UNIFAC model. The predicted results show that PDMS can be used to abate volatile organic compounds from contaminated air streams. The results obtained in this work are comparable to those obtained by the same authors through measurements such as the static headspace and the dynamic gas liquid chromatographic techniques as well as other literature. Although the UNIFAC group contribution method over estimate the infinite dilution activity coefficients, the results of this work may be applied in preliminary phases of process design, simulation and feasibility studies.
- Full Text:
- Authors: Muzenda, Edison , Simate, Geoffrey S. , Belaid, Mohamed , Ntuli, Freeman , Mollagee, Mansoor
- Date: 2011
- Subjects: Phase equilibrium , Thermodynamic models , Volatile organic compounds , Polydimethylsiloxane , Silicon oil
- Type: Article
- Identifier: uj:4699 , http://hdl.handle.net/10210/10934
- Description: This paper focuses on the phase equilibrium of volatile organic compounds in silicon oil chemically known as PDMS (polydimethylsiloxane) at infinite dilution. Measurements can be expensive and time consuming, hence the need for thermodynamic models which allow the calculation of the phase equilibrium behavior using a limited number of experimental data. The objective of this study was to predict infinite dilution activity coefficients of selected VOCs (volatile organic compounds) in PDMS using the Original UNIFAC model. The predicted results show that PDMS can be used to abate volatile organic compounds from contaminated air streams. The results obtained in this work are comparable to those obtained by the same authors through measurements such as the static headspace and the dynamic gas liquid chromatographic techniques as well as other literature. Although the UNIFAC group contribution method over estimate the infinite dilution activity coefficients, the results of this work may be applied in preliminary phases of process design, simulation and feasibility studies.
- Full Text:
Volatile organic compounds – biphenyl thermodynamic interactions
- Authors: Muzenda, Edison
- Date: 2014
- Subjects: Absorption , Activity coefficient , Phase equilibrium , Volatile organic compounds , Thermodynamics
- Type: Article
- Identifier: uj:4989 , ISSN 2078-0966 , http://hdl.handle.net/10210/13124
- Description: This work focused on the thermodynamic interactions involving volatile organic compounds (VOCs) and biphenyl. The solubility of 60 VOCs in biphenyl was studied using group contribution methods. The modified UNIFAC Dortmund and Lyngby were used to compute the required phase equilibrium in the form of infinite dilution activity coefficients. Six family groups were studied mainly alkanes, alkenes, alkynes, aldehydes, alcohols, and carboxylic acids. The Modified UNIFAC Dortmund performed better than the Modified UNIFAC Lyngby. Biphenyl showed excellent absorption affinity for all VOCs in particular for alkynes and aldehydes. The solubility decreased with increase in VOC molecular weight.
- Full Text:
- Authors: Muzenda, Edison
- Date: 2014
- Subjects: Absorption , Activity coefficient , Phase equilibrium , Volatile organic compounds , Thermodynamics
- Type: Article
- Identifier: uj:4989 , ISSN 2078-0966 , http://hdl.handle.net/10210/13124
- Description: This work focused on the thermodynamic interactions involving volatile organic compounds (VOCs) and biphenyl. The solubility of 60 VOCs in biphenyl was studied using group contribution methods. The modified UNIFAC Dortmund and Lyngby were used to compute the required phase equilibrium in the form of infinite dilution activity coefficients. Six family groups were studied mainly alkanes, alkenes, alkynes, aldehydes, alcohols, and carboxylic acids. The Modified UNIFAC Dortmund performed better than the Modified UNIFAC Lyngby. Biphenyl showed excellent absorption affinity for all VOCs in particular for alkynes and aldehydes. The solubility decreased with increase in VOC molecular weight.
- Full Text:
Volatile organic compounds – polymeric solvents interactions – a thermodynamic computational attempt
- Authors: Muzenda, Edison
- Date: 2014
- Subjects: Phase equilibrium , Solubility , Volatile organic compounds , Normal methyl pyrrolidone
- Type: Article
- Identifier: uj:4770 , ISSN 2320–4087 , http://hdl.handle.net/10210/11945
- Description: This work attempted to model the phase equilibrium involving 50 volatile organic compounds (VOCs) with furfural and normal methyl pyrrolidone (NMP). Polar furfural and dipolar aprotic NMP were tested in this work as potential solvents for the abatement of selected VOCs through physical absorption. Five (5) VOC family groups were studied namely alkanes, alkenes, alcohols, aldehydes and carboxylic groups. The modified UNIFAC Dortmund and Lyngby were used in the phase equilibrium computation. NMP showed better absorption affinity for alkenes, alcohols and carboxylic acids compared to furfural. The solubility decreased with increase in size of the VOCs for both solvents.
- Full Text:
Volatile organic compounds – polymeric solvents interactions – a thermodynamic computational attempt
- Authors: Muzenda, Edison
- Date: 2014
- Subjects: Phase equilibrium , Solubility , Volatile organic compounds , Normal methyl pyrrolidone
- Type: Article
- Identifier: uj:4770 , ISSN 2320–4087 , http://hdl.handle.net/10210/11945
- Description: This work attempted to model the phase equilibrium involving 50 volatile organic compounds (VOCs) with furfural and normal methyl pyrrolidone (NMP). Polar furfural and dipolar aprotic NMP were tested in this work as potential solvents for the abatement of selected VOCs through physical absorption. Five (5) VOC family groups were studied namely alkanes, alkenes, alcohols, aldehydes and carboxylic groups. The modified UNIFAC Dortmund and Lyngby were used in the phase equilibrium computation. NMP showed better absorption affinity for alkenes, alcohols and carboxylic acids compared to furfural. The solubility decreased with increase in size of the VOCs for both solvents.
- Full Text:
- «
- ‹
- 1
- ›
- »