دانلود رایگان مقاله تجزیه و تحلیل تنش غشاء بیوراکتورها و مخازن تاشو

Abstract

Collapsible tanks, vessels or bioreactors are finding increasing usage in small/medium scale processes because they offer flexibility and lower cost. However, if they are to be used at large scale, they need to be shown capable of handling the physical stress exerted on them. Because of their nonconventional shape and non-uniform pressure distribution, thin shell analysis cannot be used in calculating their stress. Defining curvature in terms of pressure addressed these challenges. Using curvature and numerical analysis, the membrane stress in collapsible tanks designed as bioreactors of volumes between 100 to 1000 m3 were calculated. When the liquid/gas height and static pressure are known, an equation for calculating tension per length was developed. An equation that could calculate the liquid height from the bioreactor⿿s volume, dimensions and working capacity was generated. The equation gave values of liquid height with a maximum deviation of 3% from that calculated by curvature analysis. The stress values from the liquid height and tension equations had a maximum deviation of 6% from those calculated by curvature analysis. The calculated tensile stress in a 1000 m3 collapsible tank was 14.2 MPa. From these calculations, materials that optimize both cost and safety can be selected when designing collapsible tanks.

3. Results and discussion

Collapsible tanksfindapplicationindifferentindustries andprocesses. In the biotechnology industry, they are used for making bioreactors used for biogas production [2], bioethanol production [13], biological production using plant cells [3] etc. especially at small andmediumscale. Thesebioreactors offerflexibility,low cost, easy installation and customized applicability to bio-based production [13]. If these and other benefits derived from using these types of bioreactors can be translated from small and medium scale to the large scale production of bio-products like biofuels, it could assist in increasing the economic competitiveness of the biofuels against fossil based fuels. However, in order to apply these bioreactors or any type of collapsible tank for large scale purposes they need to be able to handle the stresses exacted on them while in operations [14] and during cleaning if needed [15]. The membrane stresses of collapsible tanks meant to be used as bioreactors and that of a 1000 m3 water storage vessel were investigated using curvature and numerical analysis and the results are presented in this section.