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Item type:Publication, Access status: without files , 59 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Intensification of lipase-catalyzed esterification using ultrasound: process engineering perspectivesThe effect of cavitating ultrasound (US, 24 kHz) on the lipase-catalyzed esterification of oleic acid with 1-hexanol and 1-decanol is studied and required conditions to intensify the activity of lipase enzyme are presented. US remarkably improves the conversion rate compared to non-sonicated conditions. The influence of relevant operating parameters (amplitude, temperature, and pulsed US) on the reaction is studied. This has led to the development of strategies to operate an for energy-efficient operation of an enzyme-catalyzed ultrasonic reactor. A concept for large-scale application of the discovered phenomenon is also presented.Publicationtype: Journal Article113 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Modeling and experimental validation of hydrodynamics in an ultrasonic batch reactor(2016-07-30); ; Simulation of hydrodynamics in ultrasonic batch reactor containing immobilized enzymes as catalyst is done. A transducer with variable power and constant frequency (24 kHz) is taken as source of ultrasound (US). Simulation comprises two steps. In first step, acoustic pressure field is simulated and in second step effect of this field on particle trajectories is simulated. Simulation results are compared with experimentally determined particle trajectories using PIV Lab (particle image velocimetry). Effect of varying ultrasonic power, positioning and number of ultrasonic sources on particle trajectories is studied. It is observed that catalyst particles tend to orientate according to pattern of acoustic pressure field. An increase in ultrasonic power increases particle velocity and also brings more particles into motion. Simulation results are found to be in agreement with experimentally determined data.Publicationtype: Journal Article81 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Analysis of process intensificaiton in enzyme catalyzed reactions using ultrasoundEnzymes are biological catalysts in the form of protein which catalyze chemical reactions. They are being actively investigated for their application in chemical process industry. The key advantages associated with enzymes include their high specificity and ability of functioning at milder operating conditions. High specificity helps to minimize or eliminate side product formation [1]. Capability to function at milder operating conditions enables considerable energy efficiency and safety of the process. They also contribute to sustainable development as due to protein nature they are biodegradable and are isolated from microorganisms which are fermented using primarily renewable resources. In context of present study, intensification of enzyme catalyzed reactions using US is investigated from process engineering viewpoint. Before starting the work a comprehensive literature survey is carried out. Based on literature results a research methodology was developed to study the phenomenon in a detailed and systematic manner. According to developed methodology the work is divided into two parts. In the first part emphasis is on fundamental understanding of the phenomenon. In part 2 a reactor concept for industrial scale application of the phenomenon is developed and tested. For fundamental understanding effect of non-cavitating and cavitating ultrasound on functioning of free as well as immobilized enzymes is studied. Effect of relevant operating parameters is investigated in a systematic manner. This systematic approach has helped to understand the underlying mechanisms of the phenomenon. For the first time conditions necessary to achieve intensification effect of ultrasound are identified. Post sonication stability of enzymes was also tested to determine the reusability of enzymes. In part 2 of the study a reactor concept for large scale application of intensification effect from ultrasound was also developed and tested. Approaches for energy efficiently operation of the ultrasonic reactor are also tested. Processes based on the selected enzymes are well established in the industry. Therefore from the gained knowledge not only the new processes but the existing processes can also benefit.Publicationtype: Doctoral Thesis608 1512