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| Title: | Exergy analysis of freeze drying of pharmaceuticals in vials on trays |
| Author (s): | Liapis, Athanasios I. (Prof.) Bruttini, R. |
| Department/Lab Affiliations: | Chemical & Biological Engineering |
| Keywords: | exergy analysis exergy distribution exergy inputs exergy losses lyophilization |
| Subject Terms: | Freeze-drying. |
| Issue Date: | 2008-07 |
| Publisher: | Elsevier |
| Citation: | Liapis, A. I. and R. Bruttini. "Exergy analysis of freeze drying of pharmaceuticals in vials on trays", International Journal of Heat and Mass Transfer 51(15-16) (July 2008): 3854-3868. |
| Abstract: | The expressions for determining the exergy inputs and exergy losses due to heat and mass transfer in the primary and secondary drying stages as well as in the water vapor condenser and vacuum pump of the lyophilization process involving freeze drying of pharmaceuticals in vials on trays, are constructed and presented in this work. The structures of the exergy expressions indicate the importance of the magnitude of the duration times of the primary and secondary drying stages as well as those of the gradient of temperature and of the pressure gradients of water vapor and inerts in the material being dried, on the magnitude of the exergy inputs and exergy losses. This information is then used to indicate policies for the control variables of the lyophilization process that can result in reductions in the exergy losses in the primary and secondary drying stages, as well as in the water vapor condenser and in the vacuum pump system for heat-transfer and mass-transfer controlled freeze drying processes. The distribution of the exergy inputs and exergy losses for a lyophilization system are presented and the results show that most of the exergy input is consumed and most of the exergy losses result by the primary drying stage, the water vapor condenser, and vacuum pump in that order. By using the exergy expressions presented in this work operational control policies can be constructed that minimize the irreversibilities occurring in the operations of a freeze drying system of a given design, thus enhancing the efficiency of energy utilization in lyophilization. |
| Type: | Article - Journal text |
| In Title: | International Journal of Heat and Mass Transfer |
| Copyright Notice: | This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder. Pre-print: author can archive; Post-print: author can archive; FULL COPYRIGHT INFORMATION: |
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| title | Exergy analysis of freeze drying of pharmaceuticals in vials on trays |
| contributor.author | Liapis, Athanasios I. (Prof.) |
| contributor.author | Bruttini, R. |
| contributor.deptlab | Chemical & Biological Engineering |
| contributor.sponsor | Criofarma-Freeze Drying Equipment |
| subject | exergy analysis |
| subject | exergy distribution |
| subject | exergy inputs |
| subject | exergy losses |
| subject | lyophilization |
| subject.LCSH | Freeze-drying. |
| date.issued | 2008-07 |
| publisher | Elsevier |
| identifier.citation | Liapis, A. I. and R. Bruttini. "Exergy analysis of freeze drying of pharmaceuticals in vials on trays", International Journal of Heat and Mass Transfer 51(15-16) (July 2008): 3854-3868. |
| identifier.pub.URI | |
| description.abstract | The expressions for determining the exergy inputs and exergy losses due to heat and mass transfer in the primary and secondary drying stages as well as in the water vapor condenser and vacuum pump of the lyophilization process involving freeze drying of pharmaceuticals in vials on trays, are constructed and presented in this work. The structures of the exergy expressions indicate the importance of the magnitude of the duration times of the primary and secondary drying stages as well as those of the gradient of temperature and of the pressure gradients of water vapor and inerts in the material being dried, on the magnitude of the exergy inputs and exergy losses. This information is then used to indicate policies for the control variables of the lyophilization process that can result in reductions in the exergy losses in the primary and secondary drying stages, as well as in the water vapor condenser and in the vacuum pump system for heat-transfer and mass-transfer controlled freeze drying processes. The distribution of the exergy inputs and exergy losses for a lyophilization system are presented and the results show that most of the exergy input is consumed and most of the exergy losses result by the primary drying stage, the water vapor condenser, and vacuum pump in that order. By using the exergy expressions presented in this work operational control policies can be constructed that minimize the irreversibilities occurring in the operations of a freeze drying system of a given design, thus enhancing the efficiency of energy utilization in lyophilization. |
| type | Article - Journal |
| type.DCMIType | text |
| type.status | Postprint |
| relation.isPartOf | International Journal of Heat and Mass Transfer |
| rights | This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder. |
| rights | Pre-print: author can archive; Post-print: author can archive; |
| rights.URI | |
| identifier.persist.URI | |
| date.available | 2008-11-24T18:57:50Z |