Comparative Analysis of Biogas and Methane Yields from Different Sizes of Groundnut Shell in a Batch Reactor at Mesophilic Temperature

Abstract

Aim: To study the effects of different sizes of groundnut shell on biogas and methane yields using batch reactor at mesophilic temperature.
 Place and Duration of Study: The laboratory experiment was carried out at the Laboratory of the Department of Agricultural Engineering, Ladoke Akintola University of Technology, Ogbomoso, Nigeria, between August and October, 2018.
 Methodology: Batch experiment was set up for a period of 35 days with substrate reduced to 2, 4 and 6 mm sizes. The digesters were subjected to anaerobic digestion at mesophilic condition and the gas produced were collected with graduated gas sampling bottles dipped in measuring cylinders already filled with red liquid. The total gas produced was analyzed using gas analyzer to give the percentage composition of the gas components and Enwuff equation was used to calculate the biogas and methane yields of organic dry matter and fresh mass of the samples.
 Results: The total gas volume of 482.5, 605.0 and 732.5 ml were recorded for the sizes 2, 4 and 6 mm respectively. The organic dry matter biogas yields were 357.1, 514.31 and 324.5 lNkg-1oDM for treatment 2, 4 and 6 mm respectively; while organic dry matter methane produced were 222.41, 298.41 and 211.31 CH4kg-1oDM for 2, 4 and 6 mm, respectively. The fresh mass biogas yields were 147.6, 180.7 and 177.3 lNkg-1FM and fresh mass methane yield were 919, 104.8 and 115.4 lNCH4 kg-1FM for 2, 4 and 6 mm, respectively.
 Conclusion: Considering the yields recorded, the experiment shows that size reduction had effect on biogas yields and it is an important factor to be considered in biogas production. Treatment with particle size 4 mm seems to be the ideal size when considered the yields in terms of organic dry matter and fresh mass basis.

Modelling the effects of particle size pretreatment method on biogas yield of groundnut shells

“…Hydrolysis is perceived to be the rate-limiting stage in the process because of the substrate resistance to the enzymatic attack of the microorganisms due to their structural arrangements (Olatunji et al, 2021). This hydrolysis stage can be improved by applying pretreatment methods such as mechanical, chemical and biological pretreatments (Jekayinfa et al, 2020; Karuppiah and Ebenezer Azariah, 2019).…”

Experimental evaluation of the influence of combined particle size pretreatment and Fe3O4additive on fuel yields ofArachis Hypogeashells

“…In contrast, it does not for lignocellulose materials like rice straw and maize stalk (Menardo et al, 2012). In line with this assertion, groundnut shell has been established as a lignocellulose material that particle size reduction beyond a particular size does not favour its biogas and methane yields (Jekayinfa et al, 2020). This agrees with what was earlier noticed: if the substrate can be reduced to a point at which it is easy to degrade, overloading of digesters is possible with high organic loading, especially in the batch system.…”

“…Another similar research reported that the biogas and methane yields were enhanced until the particle size was 6 mm, but below 6 mm particle size, the yield started to reduce ( Herrmann et al, 2012 ). Jekayinfa et al (2020) reported 6 mm particle size as the optimum value for fresh biogas and methane yields of lignocellulose material. This result also supports what was reported by an earlier researcher when particle size was considered ( Olatunji et al, 2022b ).…”

“…The particle sizes selected for this research were 2, 4, 6 and 8 mm. These were done in modification to the earlier recommendation for the particle selection for anaerobic digestion of lignocellulose materials ( Jekayinfa et al, 2020 ; Menardo et al., 2012 ; Xiao et al, 2013 ). The digesters were loaded and labelled as shown in Table 3 .…”

“…Arachis Hpogea shell is one of the abundant feedstocks that have been investigated to have an excellent potential for biogas and methane generation ( Jekayinfa et al, 2020 ). The study shows that different particle sizes of Arachis hypogea significantly influence the biogas yield, and the expected yield determines the choice of particle size ( Olatunji et al, 2022b ).…”