Optimization of Raw Material Composition in an Agricultural Biogas Plant

Abstract

We analyzed the operation of a typical agricultural biogas plant in Hungary. Our aim was to optimize the composition of substrates for the biogas production and make a correct recommendation for completing feedstock recipes by considering the raw materials and technologies analyzed. The calculations were based on a very detailed database (including the daily operating data of 1673 days). Distribution of the biogas yields in summer and winter periods was normal based on the One-Sample Kolmogorov-Smirnov test, while the variance of data was homogeneous based on the Levene-test. Factor analysis of the biogas yield was performed with the Kaiser-Meyer-Olkin Measure of Sampling Adequacy probe (0.616) and the Bartlett's Test. According to the objectivity of our LP (linear program) model, we believe that a significant excess biogas yield (18-66%) could be achieved by the use of our model compared to the actual measured data. Although the amount of corn silage, grass silage, and the extract -as variables -was minimal in the recipe, they played a crucial role in the total biogas yield of the recipe because of their significantly higher organic matter contents and specific biogas yields. Our results could provide a reliable foundation for optimizing of the recipe in biogas plants with raw material base similar to the analyzed plants.

Electro-Fermentation in Aid of Bioenergy and Biopolymers

“…The first route (acetate substrate) is operated by acetoclastic methanogens while the second route (using H 2 substrate) is by hydrogenotrophic methanogenesis [89]. Factors affecting biogas production include pH, hydraulic retention time, substrate load, temperature, C/N ratio, acclimation period, and substrate composition [47,90]. For any given experimental setup controlling two or more such parameters is easy on a lab scale, while on a large scale controlling parameters, particularly the feed composition is difficult to maintain over a long period of time.…”

“…For any given experimental setup controlling two or more such parameters is easy on a lab scale, while on a large scale controlling parameters, particularly the feed composition is difficult to maintain over a long period of time. Recently, an agricultural biogas plant was used to demonstrate that optimized feed composition based on a detailed database and the linear program model could be helpful in achieving consistency in running similar biogas plants [90]. However, it was emphasized that optimization of such feedstock is promising but limited by the high organic contents contributed by maize and grass silage that governs the majority of the biogas produced.…”

“…Any transient decrease in the feedstock may raise the energy crops proportion within the substrates, leading to higher biogas evolution. The requirement of land to grow energy crops is comparatively less than food-crops; therefore, a systematic economic evaluation of any given agricultural biogas plant is desirable [90,91]. Besides the above-mentioned major factors, the changes in microbial communities during the operation cycle have been studied.…”

Economic Analysis of Pellet Production in Co-Digestion Biogas Plants

“…While the economical aspect of biogas production can be most easily improved by increasing the organic load [15] or by optimizing the recipe [16], the use of waste heat also significantly influences operational results.…”

“…To optimize the dry matter content of the substrate, a linear programming (LP) model was used, similarly to our previous study [16]. Additionally, LP has been used as a model by several authors in biogas plant testing [66,67].…”