| 1. |
- Astuti, E., et al.
(författare)
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Determination of the temperature effect on glycerol nitration processes using the HYSYS predictions and the laboratory experiment
- 2014
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Ingår i: Indonesian Journal of Chemistry. - : Universitas Gadjah Mada. - 1411-9420 .- 2460-1578. ; 14:1, s. 57-62
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Tidskriftsartikel (refereegranskat)abstract
- Determinations of the temperature effect on glycerol nitration processes have been done with two methods: the HYSYS predictions and the laboratory experiment. The aim of this study was to compare prediction method and laboratory experiment method. The highest equilibrium conversion from HYSYS predictions was obtained in the range of equilibrium temperature of 10 to 20 °C. The laboratory experiments also described that nitration of glycerol with nitric acid should be carried out at reaction temperature of 10 to 20 °C. HYSYS that was used to predict the results of experiments in the laboratory can reduce the laboratory work with minimize the range of operating conditions studied. HYSYS exactly predict temperature of nitration of glycerol. The difference in conversion between two methods due to the equipment that was used in the experiments, procedure of experiments and the accuracy of analysis.
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| 2. |
- Burman, Åsa Ulrika, 1969, et al.
(författare)
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Calculation of Vapor Liquid Equilibrium and Excess Enthalpy with the UNIQUAC Equation
- 2007
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Ingår i: Chemical Engineering Communications. - : Informa UK Limited. - 0098-6445 .- 1563-5201. ; 194:8, s. 1040-1063
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Tidskriftsartikel (refereegranskat)abstract
- The UNIQUAC equation was used for calculation of vapour liquid equilibrium (VLE) as well as excess enthalpy (hE). Four sets of binary interaction parameters were applied: first, parameters estimated only from VLE data, then parameters from hE data for both the original UNIQUAC equation and first the Anderson modification, and finally parameters estimated from hE and VLE data simultaneously. Calculations were performed for seven binary systems with polar components, representing different hE behaviour. The crossprediction of hE from VLE data works better than the reversed prediction. The model with parameters estimated simultaneously to both kinds of data, can be applied successfully to both kinds of calculations, but it is a compromise between the models estimated from one kind of data.
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| 3. |
- Burman, Åsa Ulrika, 1969, et al.
(författare)
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Excess Enthalpy and Vapor-Liquid Equilibria with the MHV2 and Soave Mixing Rules
- 2011
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Ingår i: Chemical Engineering Communications. - : Informa UK Limited. - 0098-6445 .- 1563-5201. ; 198:11, s. 1435-1452
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Tidskriftsartikel (refereegranskat)abstract
- Calculations and predictions of excess enthalpy (H-E) and vapor-liquid equilibrium (VLE) were performed using the Gibbs energy mixing rules MHV2 and a modification of it by Soave. The Soave-Redlich-Kwong equation of state was combined with the UNIQUAC equation. Four sets of parameters estimated in the UNIQUAC model were used for each of seven binary systems: the first estimated from VLE data, the second and the third estimated from H-E data for two versions of the UNIQUAC equation, and the fourth estimated from both H-E and VLE data simultaneously. It was found that H-E calculations can be performed with the mixing rules; the average relative errors fell from around 200% for the conventional mixing rule to around 60% for MHV2 combined with DECHEMA UNIQUAC parameters and was as little as 20% when the UNIQUAC parameters had been estimated from H-E and VLE data simultaneously. However, the approach suffers from the same shortcomings as far as cross-prediction between H-E and VLE data is concerned, as does the UNIQUAC equation used alone. There is a discrepancy between values obtained with the mixing rule and those obtained with the UNIQUAC equation directly. This discrepancy is smaller for the Soave modification of the mixing rule.
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| 4. |
- Burman, Åsa Ulrika, 1969, et al.
(författare)
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Vapor-Liquid Equilibrium for Mixtures of Ethylethylenediamine, Ethylenediamine, and Water
- 2013
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Ingår i: Journal of Chemical & Engineering Data. - : American Chemical Society (ACS). - 0021-9568 .- 1520-5134. ; 58:2, s. 257-263
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Tidskriftsartikel (refereegranskat)abstract
- he temperature and the composition of the vapor and liquid phases at equilibrium were measured at atmospheric pressure and (SO and 20) kPa for the binary mixtures: water (I) and ethylenediamine (2, EDA); water and ethylethylenediamine (3, EtEDA); and EDA and EtEDA. For the ternary mixture of water, EDA, and EtEDA, equilibrium conditions were measured at atmospheric pressure. The vapor pressure of EtEDA was measured in the temperature range from (358 to 402) K, and Antoine parameters were fitted to the data. Parameters for the universal quasichemical (UNIQUAC) equation are estimated from binary data and applied to the ternary mixture. It was shown that the mixture of EDA and EtEDA has a zeotropic pinch close to pure EDA. Furthermore, it was found that the ternary mixture has a saddle point azeotrope at a molar fraction of 0.24 of water, 0.62 of EDA, and 0.14 of EtEDA and a temperature of 392.6 K at atmospheric pressure. Thus, the volatility between EDA and EtEDA is reversed in the water-rich region, and EtEDA is the most volatile component close to the binary azeotrope between water and EDA. This is illustrated by univolatility lines in a ternary diagram.
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| 5. |
- Mattsson, Karin, 1975, et al.
(författare)
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Aspects on metal ion distribution models in pulp washing simulation
- 2007
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Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 58:2, s. 262-266
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Tidskriftsartikel (refereegranskat)abstract
- The closure of the liquid system in a pulp mill has increased the concentration of metal ions in the process as compared to traditional plants. These ions commonly referred to as non-process elements, NPE, enter the pulp mill with the wood chips, the water supply and the pulping chemicals. The presence of these ions may lead to various problems, e.g. incrust formation, filtration failures and reduced bleaching efficiency and the objective of the pulp washing operation is to remove a major part of these metal ions from the pulp.The objective of this work was to study the influence of sorption of metal ions on the simulation of pulp washing.A process simulator, ASPEN Plus, has been used to describe the different steps in a displacement drum washer. In order to take account of the sorption of metal ions on the pulp fibres blocks with FORTRAN subroutines have been developed and included. The simulations studies show that the washing results are quite similar for all models at high concentration levels. Hence, the adsorption does not contribute significantly except for low concentration cases. The influence of the sorption model and thus also the choice of model is important only in washing stages where the concentration of ions is very low.Comparison with data for an industrial displacement drum washer indicated the usefulness of the simulation model in evaluation of the operation. It was found that the displacement-washing step was far from ideal probably due to uneven liquid distribution and formation problems. For washing of solids other than paper pulp, e.g. lime mud, the effect of sorption metal ions on the washing result is less pronounced and a simpler model can be used with good results.
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| 6. |
- Mattsson, Karin, 1975, et al.
(författare)
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Washing of pulp using evaporator condensate
- 2009
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Ingår i: Nordic Pulp and Paper Research Journal. - 2000-0669 .- 0283-2631. ; 24:4, s. 421-427
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Tidskriftsartikel (refereegranskat)abstract
- One way to effectively reduce the water consumption and obtain a wash liquid with low concentration of metal ions at the pulp mill IS to use recycled condensate as wash liquid. The condensate originates froth the evaporator system where. recycled liquor is evaporated before it is burnt ill the recovery boiler The main problem with recycling of condensate is the fact that these always contain Impurities of varying concentration These Impurities plainly cause odour problems in the process or in the final product To investigate the field of application, one unbleached pulp and ogle blenched pulp were washed with four different condensates with different COD concentrations the washing results were consistently good for condensates with low concentration of COD, but sonic Unexpected results were obtained for the case where the condensate with the highest concentration of COD was used To investigate the characteristics of the pulp, an adsorption study including manganese, calcium and magnesium was performed. The adsorbed amounts of ions were all fouled to be within the normal range.
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| 7. |
- Ström, Krister, 1956, et al.
(författare)
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Density for Water + Ethylenediamine at Temperatures between 283 and 353 K
- 2008
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Ingår i: Journal of Chemical & Engineering Data. - : American Chemical Society (ACS). - 0021-9568 .- 1520-5134. ; 53:10, s. 2307-2310
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Tidskriftsartikel (refereegranskat)abstract
- The density for mixtures of ethylenediamine (EDA) and water at 0.2 MPa was measured with a vibrating tube densitometer in the temperature range of 283 K to 353 K at intervals of 10 K. The entire composition range was covered with intervals of molar fractions of 10 %. The excess volume has a minimum at a molar fraction of water of 59 %, corresponding to a maximum at 69 % in the departure from additivity in density. The variation with temperature in excess volume is small, but for density it is complex. The temperature dependence in density is well described by combining a Redlich-Kister model for excess volume without temperature dependent parameters with models for the pure component densities.
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| 8. |
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| 9. |
- Ström, Krister, 1956, et al.
(författare)
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Icke-azeotropa blandningar av köldmedier i stora värmepumpar - en förstudie
- 1982
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- En förstudie inom området icke-azeotropa blandningar avköldmedier i stora värmepumpar har genomförts vid institutionerna för Värmeteknik och maskinlära och Kemisk apparat- och anläggningsteknik vid Chalmers tekniska högskola. Arbetet presenteras i form av två delrapporter, nr I från Kemisk apparat- och anläggningsteknik och nr II från Värmeteknik och maskinlära. Målet med förstudien har varit dels att utvärdera noggrannheten och användbarheten av vid CTH befintlig utrustning för uppmätning av vissa blandningsegenskaper (delrapport I), dels att genom överslagsberäkningar finna tekniskt intressanta köldmedieblandningar för användning i kompressordrivna värmepumpsystem (delrapport II). I den senare delrapporten har framför allt undersökts vilka möjligheter det finns att öka kapaciteten hos värmepumpar med hjälp av blandningar.
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