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Mohanta H.K.,Chemical Engineering Group | Gupta R.K.,ICFAI University, Tripura
International Journal of Automation and Control | Year: 2010

This paper presents an online implementation of wavelet-based least-square identification (WLSI) and wavelet-based dynamic matrix control (WDMC) in a plate-type heat exchanger unit. Wavelet domain 'blocking' and 'condensing' (B&C) techniques are used to reduce the computation time for optimisation of dynamic matrix control (DMC) performance index. Algorithms for WLSI and WDMC are developed and implemented in the online identification and control of temperature in a heat exchanger unit. The results are compared with conventional PID and DMC controllers. It is observed that the WDMC is better and robust than the other controllers. © 2010 Inderscience Enterprises Ltd.

Mollekopf N.,TU Dresden | Treppe K.,TU Dresden | Fiala P.,TU Dresden | Dixit O.,Chemical Engineering Group
Chemie-Ingenieur-Technik | Year: 2011

The study focuses on the vacuum microwave treatment of low-moisture potato starch. Typical temperature and drying profiles are presented and explained with the help of other process parameters such as sample weight, pressure, incident and absorbed microwave power. Subsequently water absorption capacity of vacuum microwave treated and conduction heated samples was investigated at 55°C. During vacuum microwave treatment, 50 g samples were treated with incident powers of 460, 500 and 750 W at 3800 Pa for durations between 30 and 300 s. Water absorption capacity increased exponentially with the net absorbed energy but could not be functionally correlated to end temperature and incident power. During conduction heating, starch samples were treated at temperature values of 120, 130, 140, 150 and 160°C, till constant weight. The water absorption capacity was observed to increase with increase in treatment temperature. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Soltani I.,Chemical Engineering Group | Zeynali M.,Iran Polymer And Petrochemical Institute | Yousefi A.,Iran Polymer And Petrochemical Institute
Gummi, Fasern, Kunststoffe | Year: 2013

In this research the variation of mechanical and rheological properties of the composite as a function of different processing parameters and EPDM content was studied. The optimum amount of dicumyl peroxide (DCP) to achieve the highest percentage of grafting of maleic anhydride to EPDM was obtained by FTIR spectroscopy. In general, immiscibility between nylon 66 and EPDM and their high interfacial tension makes their blending difficult. Maleic anhydride was grafted to EPDM to reduce interfacial tension between two phases. Also the blends were prepared at the highest possible mixing speed (screw speed in extrusion) and lowest temperature to reach a well mixed sample which can be seen in SEM images and impact strength results. DMTA tests were conducted to evaluate the miscibility of the components and to measure the glass transition temperature of the blends. Rheological measurements showed the viscosities of the blend components getting closer to each other when EPDM content, time of mixing, and shear rate increase.

Ummadisingu A.,Chemical Engineering Group | Sheth P.,Faculty Division 1 | Babu B.V.,Birla Institute of Technology and Science
10AIChE - 2010 AIChE Annual Meeting, Conference Proceedings | Year: 2010

Biomass is the oldest form of energy used by human beings, mainly in the form of wood. It is a renewable source of energy and has many advantages from an ecological point of view. The direct combustion of biomass generates concern among environmentalists, as it is incomplete and inconsistent and may produce organic particulate matter, carbon monoxide and other organic gases. Biomass gasification has attracted the greatest interest as it offers a higher efficiency as compared to combustion and pyrolysis. Gasification is the process of conversion of solid carbonaceous fuel into combustible gas by partial combustion. Various groups of researchers have carried out experimental studies on downdraft biomass gasifier with different biomass materials such as wood, wood chips, hazelnut shell, agricultural wastes, saw dust, etc. It is reported that bridging is a normal occurrence in the gasifier. It occurs mainly in the pyrolysis zone of the downdraft biomass gasifier. In the present study, wood shavings of pine wood are used as biomass in a downdraft biomass gasifier. To overcome bridging, the design of the biomass gasifier is modified by incorporating a shaking mechanism. With this modified design of the biomass gasifier, experiments are carried out with pine wood (Pinus roxburghii) shavings as biomass covering wide range of operating conditions. The performance of the biomass gasifier system is evaluated in terms of equivalence ratio, producer gas composition, calorific value of the producer gas, gas production rate, zone temperatures and cold gas efficiency.

Sheth P.N.,Birla Institute of Technology and Science | Sheth P.N.,Chemical Engineering Group | Amita U.,Birla Institute of Technology and Science | Amita U.,Chemical Engineering Group | Babuc B.V.,Birla Institute of Technology and Science
10AIChE - 2010 AIChE Annual Meeting, Conference Proceedings | Year: 2010

Kinetics-free equilibrium models can predict the exit gas composition of the biomass gasifier, given the solid composition and the equilibrium temperature, but they cannot be used for reactor design. Hence, there is a need to develop a combined transport and kinetic model which takes into account of the kinetics of homogeneous and heterogeneous chemical reactions, transport of volatiles produced, heat and mass transfer between solid and gaseous phase and pyrolysis reactions. Taking into account of the importance of downdraft biomass gasifier and its commercial applications, it is essential to have a complete model for such a configuration. In the present study, a transient onedimensional model is developed for the throated close-top downdraft biomass gasifier. The model takes into account of the drying, pyrolysis, secondary tar reactions, homogeneous gas reactions and heterogeneous combustion/gasification reactions. The experimental data obtained in our earlier study are used to validate the simulation results of the complete combined transport and kinetic model. The fraction of initial moisture content, air flow rate, temperature of the drying & pyrolysis zone, and chemical composition of the biomass are required as input data for the model to predict the composition of producer gas. The variation of molar fraction of producer gas components with time is predicted and compared with the experimental data. It is concluded from the present study that the developed model can predict the performance of the biomass gasifier, a priori. The results of this study are also useful in the design of a downdraft biomass gasifier.

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