Chemical and Biochemical Engineering Quarterly, 2009
Spray distributors as used in conjunction with large diameter packed beds consist of a multiplici... more Spray distributors as used in conjunction with large diameter packed beds consist of a multiplicity of spray nozzles that produce a circular liquid distribution pattern, arranged in a rectangular grid with a large degree of overlap to avoid "dry spots". This inherent non-uniformity is reflected in an uneven cross sectional distribution of the liquid, the extent of which depends on the factors such as spray angle, homogeneity of spray cones, nozzle pattern, and, importantly, the distance between the nozzles and the bed. The information on the performance of spray distributors is scarce and mainly qualitative, and therefore it is not surprising that rules for spray distributor design are unavailable in open literature. This paper aims at filling this gap and describes experiments carried out to characterize the liquid distribution of a 4-nozzle distributor, equipped with full-cone, wide-angle spray nozzles. The TU Delft column hydraulics simulator with an internal diameter of 1.4 m was used for this purpose. The test system was water/air at atmospheric pressure and ambient temperature. Particular attention was paid to the effects of the nozzle pressure and the spacing between the nozzles and the bed; however, the distance required to smooth out poor initial distribution to an acceptable level appeared to be impractical.
Chemical and Biochemical Engineering Quarterly, 2009
Spray distributors as used in conjunction with large diameter packed beds consist of a multiplici... more Spray distributors as used in conjunction with large diameter packed beds consist of a multiplicity of spray nozzles that produce a circular liquid distribution pattern, arranged in a rectangular grid with a large degree of overlap to avoid "dry spots". This inherent non-uniformity is reflected in an uneven cross sectional distribution of the liquid, the extent of which depends on the factors such as spray angle, homogeneity of spray cones, nozzle pattern, and, importantly, the distance between the nozzles and the bed. The information on the performance of spray distributors is scarce and mainly qualitative, and therefore it is not surprising that rules for spray distributor design are unavailable in open literature. This paper aims at filling this gap and describes experiments carried out to characterize the liquid distribution of a 4-nozzle distributor, equipped with full-cone, wide-angle spray nozzles. The TU Delft column hydraulics simulator with an internal diameter of 1.4 m was used for this purpose. The test system was water/air at atmospheric pressure and ambient temperature. Particular attention was paid to the effects of the nozzle pressure and the spacing between the nozzles and the bed; however, the distance required to smooth out poor initial distribution to an acceptable level appeared to be impractical.
Industrial & Engineering Chemistry Research, 1999
Comprehensive experimental studies have been conducted with several varieties of commercial struc... more Comprehensive experimental studies have been conducted with several varieties of commercial structured packing to ascertain geometry-imposed effects on their hydraulic behavior. At Delft, the air-water system was used for hydraulic studies, and at the Separations Research Program (SRP) the cyclohexane/n-heptane distillation system was used to provide additional hydraulic and mass-transfer data for the same packings. These and other performance data available in the SRP database have been used to substantiate the development of a physically sound, generally applicable empirical correlation for predicting the onset of loading, where hydraulic characteristics of the packed bed change significantly. The correlation proposed in this paper covers a wide range of operating conditions and variations in structured packing geometry. It can be used with either Delft or SRP preloading models to provide an outgoing point for determining pressure drop, liquid holdup, and mass transfer in the loading region.
Industrial & Engineering Chemistry Research, 1999
Comprehensive experimental studies have been conducted with several varieties of commercial struc... more Comprehensive experimental studies have been conducted with several varieties of commercial structured packing to ascertain geometry-imposed effects on their hydraulic behavior. At Delft, the air-water system was used for hydraulic studies, and at the Separations Research Program (SRP) the cyclohexane/n-heptane distillation system was used to provide additional hydraulic and mass-transfer data for the same packings. These and other performance data available in the SRP database have been used to substantiate the development of a physically sound, generally applicable empirical correlation for predicting the onset of loading, where hydraulic characteristics of the packed bed change significantly. The correlation proposed in this paper covers a wide range of operating conditions and variations in structured packing geometry. It can be used with either Delft or SRP preloading models to provide an outgoing point for determining pressure drop, liquid holdup, and mass transfer in the loading region.
Abstract The commonly-used absorber calculation methods use, as initial profiles, estimates of co... more Abstract The commonly-used absorber calculation methods use, as initial profiles, estimates of column temperatures, gas rates etc. This paper describes a new simple calculation method that eliminates the need for estimates for hydrocarbon absorber calculations. Examples involving a wide range of operating conditions are given to illustrate the reliability of the proposed method.
Abstract The commonly-used absorber calculation methods use, as initial profiles, estimates of co... more Abstract The commonly-used absorber calculation methods use, as initial profiles, estimates of column temperatures, gas rates etc. This paper describes a new simple calculation method that eliminates the need for estimates for hydrocarbon absorber calculations. Examples involving a wide range of operating conditions are given to illustrate the reliability of the proposed method.
This paper presents results of continuous feed and total reflux distillation experiments carried ... more This paper presents results of continuous feed and total reflux distillation experiments carried out with a common type and size structured packing using two- and three-component mixtures of common alcohols and water. With the binary mixture, the packing performed slightly better than with a three-component mixture. Surprisingly, the continuous operation performance appeared slightly better than in case of the total
Results are presented of total reflux experiments carried out at Fractionation Research Inc. with... more Results are presented of total reflux experiments carried out at Fractionation Research Inc. with Montz-Pak A3-500M, an advanced corrugated sheet wire gauze packing, using paraxylene/orthoxylene system at 0.02 and 0.1 bara, respectively. In both cases an expectedly good performance was achieved, ranging from eight stages at low- to four stages per unit bed height at high vapor loads. Interestingly, within preloading region the packing exhibited better efficiency at 0.02 bara, however this was at the expense of somewhat increased pressure drop, and, strikingly, no gain on capacity side. Delft model proved capable of capturing observed trends, but exhibits a pronounced discrepancy with respect to measured efficiency and pressure drop at 0.02 bara, and suggests a higher flooding limit than observed.
Although potential for reduction of energy requirement and related carbon dioxide emissions is hi... more Although potential for reduction of energy requirement and related carbon dioxide emissions is highly attractive – around 50% compared to conventional three column sequences – process industries are still reluctant to consider implementation of four products fully thermally coupled dividing wall columns, mainly due to concerns related to controllability of two or three vapor splits as encountered in complex DWC arrangements. This paper presents results of a simulation study that could bring some relief in this respect, indicating that a temperature-driven control structure, in conjunction with very tight control of temperature profiles in prefractionation section, as well as in the product draw regions of the column, is capable of restoring the operation to health from typical disturbances in feed quality.
In order to meet current carbon dioxide emissions reduction challenges, natural gas processing an... more In order to meet current carbon dioxide emissions reduction challenges, natural gas processing and refining industries have to find the ways to minimize energy requirements of distillation operations. Building on foundations lied down in a preceding effort, this paper shows that this could be achieved in a cost-effective way in natural gas liquids fractionation plants and that a conventional demethanizer column combined with either a thermally coupled direct sequence of deethanizer and propane-butane recovery columns or a dividing wall column produces expected savings in capital and hot utilities costs as compared to conventional direct sequence, without any temperature penalty on cold utilities side. The choice between available options will largely depend on important process considerations that may differ for offshore and onshore plants to the extent depending on specific site requirements.
Chemical and Biochemical Engineering Quarterly, 2009
Spray distributors as used in conjunction with large diameter packed beds consist of a multiplici... more Spray distributors as used in conjunction with large diameter packed beds consist of a multiplicity of spray nozzles that produce a circular liquid distribution pattern, arranged in a rectangular grid with a large degree of overlap to avoid "dry spots". This inherent non-uniformity is reflected in an uneven cross sectional distribution of the liquid, the extent of which depends on the factors such as spray angle, homogeneity of spray cones, nozzle pattern, and, importantly, the distance between the nozzles and the bed. The information on the performance of spray distributors is scarce and mainly qualitative, and therefore it is not surprising that rules for spray distributor design are unavailable in open literature. This paper aims at filling this gap and describes experiments carried out to characterize the liquid distribution of a 4-nozzle distributor, equipped with full-cone, wide-angle spray nozzles. The TU Delft column hydraulics simulator with an internal diameter of 1.4 m was used for this purpose. The test system was water/air at atmospheric pressure and ambient temperature. Particular attention was paid to the effects of the nozzle pressure and the spacing between the nozzles and the bed; however, the distance required to smooth out poor initial distribution to an acceptable level appeared to be impractical.
Chemical and Biochemical Engineering Quarterly, 2009
Spray distributors as used in conjunction with large diameter packed beds consist of a multiplici... more Spray distributors as used in conjunction with large diameter packed beds consist of a multiplicity of spray nozzles that produce a circular liquid distribution pattern, arranged in a rectangular grid with a large degree of overlap to avoid "dry spots". This inherent non-uniformity is reflected in an uneven cross sectional distribution of the liquid, the extent of which depends on the factors such as spray angle, homogeneity of spray cones, nozzle pattern, and, importantly, the distance between the nozzles and the bed. The information on the performance of spray distributors is scarce and mainly qualitative, and therefore it is not surprising that rules for spray distributor design are unavailable in open literature. This paper aims at filling this gap and describes experiments carried out to characterize the liquid distribution of a 4-nozzle distributor, equipped with full-cone, wide-angle spray nozzles. The TU Delft column hydraulics simulator with an internal diameter of 1.4 m was used for this purpose. The test system was water/air at atmospheric pressure and ambient temperature. Particular attention was paid to the effects of the nozzle pressure and the spacing between the nozzles and the bed; however, the distance required to smooth out poor initial distribution to an acceptable level appeared to be impractical.
Industrial & Engineering Chemistry Research, 1999
Comprehensive experimental studies have been conducted with several varieties of commercial struc... more Comprehensive experimental studies have been conducted with several varieties of commercial structured packing to ascertain geometry-imposed effects on their hydraulic behavior. At Delft, the air-water system was used for hydraulic studies, and at the Separations Research Program (SRP) the cyclohexane/n-heptane distillation system was used to provide additional hydraulic and mass-transfer data for the same packings. These and other performance data available in the SRP database have been used to substantiate the development of a physically sound, generally applicable empirical correlation for predicting the onset of loading, where hydraulic characteristics of the packed bed change significantly. The correlation proposed in this paper covers a wide range of operating conditions and variations in structured packing geometry. It can be used with either Delft or SRP preloading models to provide an outgoing point for determining pressure drop, liquid holdup, and mass transfer in the loading region.
Industrial & Engineering Chemistry Research, 1999
Comprehensive experimental studies have been conducted with several varieties of commercial struc... more Comprehensive experimental studies have been conducted with several varieties of commercial structured packing to ascertain geometry-imposed effects on their hydraulic behavior. At Delft, the air-water system was used for hydraulic studies, and at the Separations Research Program (SRP) the cyclohexane/n-heptane distillation system was used to provide additional hydraulic and mass-transfer data for the same packings. These and other performance data available in the SRP database have been used to substantiate the development of a physically sound, generally applicable empirical correlation for predicting the onset of loading, where hydraulic characteristics of the packed bed change significantly. The correlation proposed in this paper covers a wide range of operating conditions and variations in structured packing geometry. It can be used with either Delft or SRP preloading models to provide an outgoing point for determining pressure drop, liquid holdup, and mass transfer in the loading region.
Abstract The commonly-used absorber calculation methods use, as initial profiles, estimates of co... more Abstract The commonly-used absorber calculation methods use, as initial profiles, estimates of column temperatures, gas rates etc. This paper describes a new simple calculation method that eliminates the need for estimates for hydrocarbon absorber calculations. Examples involving a wide range of operating conditions are given to illustrate the reliability of the proposed method.
Abstract The commonly-used absorber calculation methods use, as initial profiles, estimates of co... more Abstract The commonly-used absorber calculation methods use, as initial profiles, estimates of column temperatures, gas rates etc. This paper describes a new simple calculation method that eliminates the need for estimates for hydrocarbon absorber calculations. Examples involving a wide range of operating conditions are given to illustrate the reliability of the proposed method.
This paper presents results of continuous feed and total reflux distillation experiments carried ... more This paper presents results of continuous feed and total reflux distillation experiments carried out with a common type and size structured packing using two- and three-component mixtures of common alcohols and water. With the binary mixture, the packing performed slightly better than with a three-component mixture. Surprisingly, the continuous operation performance appeared slightly better than in case of the total
Results are presented of total reflux experiments carried out at Fractionation Research Inc. with... more Results are presented of total reflux experiments carried out at Fractionation Research Inc. with Montz-Pak A3-500M, an advanced corrugated sheet wire gauze packing, using paraxylene/orthoxylene system at 0.02 and 0.1 bara, respectively. In both cases an expectedly good performance was achieved, ranging from eight stages at low- to four stages per unit bed height at high vapor loads. Interestingly, within preloading region the packing exhibited better efficiency at 0.02 bara, however this was at the expense of somewhat increased pressure drop, and, strikingly, no gain on capacity side. Delft model proved capable of capturing observed trends, but exhibits a pronounced discrepancy with respect to measured efficiency and pressure drop at 0.02 bara, and suggests a higher flooding limit than observed.
Although potential for reduction of energy requirement and related carbon dioxide emissions is hi... more Although potential for reduction of energy requirement and related carbon dioxide emissions is highly attractive – around 50% compared to conventional three column sequences – process industries are still reluctant to consider implementation of four products fully thermally coupled dividing wall columns, mainly due to concerns related to controllability of two or three vapor splits as encountered in complex DWC arrangements. This paper presents results of a simulation study that could bring some relief in this respect, indicating that a temperature-driven control structure, in conjunction with very tight control of temperature profiles in prefractionation section, as well as in the product draw regions of the column, is capable of restoring the operation to health from typical disturbances in feed quality.
In order to meet current carbon dioxide emissions reduction challenges, natural gas processing an... more In order to meet current carbon dioxide emissions reduction challenges, natural gas processing and refining industries have to find the ways to minimize energy requirements of distillation operations. Building on foundations lied down in a preceding effort, this paper shows that this could be achieved in a cost-effective way in natural gas liquids fractionation plants and that a conventional demethanizer column combined with either a thermally coupled direct sequence of deethanizer and propane-butane recovery columns or a dividing wall column produces expected savings in capital and hot utilities costs as compared to conventional direct sequence, without any temperature penalty on cold utilities side. The choice between available options will largely depend on important process considerations that may differ for offshore and onshore plants to the extent depending on specific site requirements.
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