Membrane stress analysis of collapsible tanks andbioreactors

• Collapsible tanks, vessels or bioreactors are finding increasing usage in small/medium scaleprocesses because they offer flexibility and lower cost. However, if they are to be used atlarge 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 shellanalysis cannot be used in calculating their stress. Defining curvature in terms of pressureaddressed these challenges. Using curvature and numerical analysis, the membrane stress incollapsible tanks designed as bioreactors of volumes between 100-1000 m3 were calculated.When the liquid/gas height and static pressure are known, an equation for calculating tensionper length was developed. An equation that could calculate the liquid height from thebioreactor’s volume, dimensions and working capacity was generated. The equation gavevalues of liquid height with a maximum deviation of 3% from that calculated by curvatureanalysis. The stress values from the liquid height and tension equations had a maximumdeviation of 6% from those calculated by curvature analysis. The calculated tensile stress in a1000 m3 collapsible tank was 14.2 MPa. From these calculations, materials that optimize bothcost and safety can be selected when designing collapsible tanks.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik -- Annan kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering -- Other Chemical Engineering (hsv//eng)

Keyword

Pressure vessel; Collapsible tank; Bioreactor; Stress calculations; Stress relation; Curvature analysis; Biofuel production

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ref (subject category)

art (subject category)