(263d) Process Simulation and Experimental Investigation of Biofuel Production in a High RATE Anaerobic Digestion Process

Authors: 
Al-Rubaye, H., Missouri Science and Technology
Manchenahalli, M., Missouri University Science and Technology
The non-hazardous waste management hierarchy of the US EPA calls for “Reduce,
Reuse, and Recycle” (or the three R’s) of wastes. The anaerobic digestion process is one
of the most important methods that used to treat the wastes and at the same time generate
energy out of it. The anaerobic digestion process generates a mixture of methane and
carbon dioxide gases which is known as biogas. The biogas composition is about 50-70%
methane and 10-30% of carbon dioxide and trace amount of other gases like hydrogen and
hydrogen sulfide. This biogas can be used in power generation, heating systems and in
combined heating and powering systems. Also, it could be upgraded to improve its quality
and make is utilized in all equipment used for natural gas with a minimal adjustment due
to the lower BTU contents for methane gas. Three papers were written and submitted
regarding the biogas production and the liquid waste water treatment. The first paper
focuses on developing a process modeling simulation by aspen plus for the anaerobic
digestion process and on conducting a sensitivity analysis to investigate the parameters that
could upgrade the biogas quality. The second paper focuses on the effect of hydraulic
retention time of the substrate on the biogas production. This investigation conducted in a
two-stage high rate expanded granular sludge bed reactor under different variables like
substrate concentration, organic loading rate, and operating temperature. The third paper
focuses on upgrading the biogas quality and quantity in a two-stage expanded granular
sludge bed reactor by investigating the effect of injecting the pre-acidification gas (the first
stage), which is mainly produced a gas mixture consist of hydrogen and carbon dioxide)
into the second stage (the expanded granular sludge bed reactor).