In today’s world the use of energy is significantly increasing, so it is essential to develop and sustain other sources of renewable energy, including biogas which is derived from organic matter like food waste. This paper aims to develop a sustainable method for repurposing and recycling food waste through an anaerobic digestion process to generate biogas. The study evaluates the effectiveness of extracting biogas from food waste using a digester or bioreactor implemented with multiple airlift pumps, a deviation from using the less efficient traditional continuous stirred tank reactors (CSTRs). The evaluated digester has multiple airlift pumps implemented at equally spaced circumferential locations, that reinject biogas to circulate and blend the liquid sludge, thereby enhancing the mixing rate of the liquid sludge within the digester. Additionally, computational fluid dynamics (CFD) simulation was utilized to examine the mixing process within the digester when four standard riser airlift pumps were implemented within the digester. The analysis involved evaluating the velocity contours of air-water with those of biogas-liquid sludge. It also observes the differences in the average velocity of water and liquid sludge, examining the change in rheological property, Newtonian and/or non-Newtonian, behavior for liquid sludge at a different mass flow rate of biogas. The study revealed that despite the high viscosity and density of the liquid sludge, the average velocity of the liquid sludge follows the same trend of average velocity observed in water, concluding that the liquid sludge acts like a Newtonian fluid in terms of the average velocity and shear rates within the digester at low mass flow rates of both liquid and gas phases.  

Title

Proceedings of the 11th International Conference on Fluid Flow, Heat and Mass Transfer (FFHMT 2024)

Publisher

FFHMT 2024

Publisher Country

Canada

Indexing

Scopus

Impact Factor

None

Publication Type

Both (Printed and Online)

Volume

--

Year

2024

Pages

(034) 1-7