Pig slurry - A polydisperse substrate necessary for the biogasification of a lignite bed

Abstract

The in situ transformation of the carbohydrate substances is presented in the context of methane (CH4) formation by methanogens. In situ coal conversion methods have been characterized due to the beneficial effect of unconventional coal mining. The research was carried out on less mature coals, with a lower carbonisation degree of organic matter, because they are more effective in conversion to bioenergy gas, which can be used for all pro-ecological activities. The original concept of experimental research was presented by combining the properties of a polydisperse substrate, which is pig slurry, and used for brown coal biogasification (anaerobic digestion) in two brown coal bed systems. For this purpose, a laboratory monosubstrate reactor for the fermentation of pig slurry in a lignite bed was developed. The mainaim of the research presented in the article is to assess the amount of agricultural biogas produced in the process of mesophilic methane fermentation with the use of a polydisperse substrate using a brown coal bed placed in a fermentor. The partial goals are:- presentation of analogies of techniques and methods of underground coal gasification (UCG) to biogasification of brown coal;- a set of correlation equations for calculating flow resistance coefficients through granular porous structures;- comparison of experimental values of flow resistance with calculations according to various models.The justification of the main goal and partial goals refers to the development of a new technique and method of obtaining biogas, taking into account the Reynolds number and the own model of the gas flow resistance coefficient.The novelty of the article are: developed own model for determining the correlation dependence of the flow resistance coefficient as a function of the Reynolds number, - the results of research that indicate the practical use of pig slurry in a lignite bed for which intensive biogas production takes place at lignite.- minor deposit in relation to lignite - flat fragments of a deposit. The inhibition phenomenon and the dynamics of the process during the production of biogas in the brown coal bed were also observed in the research. An additional advantage of the innovation in the article is the combination of a polydisperse substrate with a porous bed - the simplicity of the research is the production of biogas on a lignite bed, which is a medium for biogas-producing bacteria.It has been shown that:- the developed lignite biogasification system with the participation of a polydisperse substrate in the fermenter (laboratory vessel) ensures the production of biogas in the absence of thermal insulation of the fermenter;- for a lignite deposit, the biogas stream is stable with increasing temperature; while above the temperature of 38 °C–42 °C, the biogas stream is characterized by a downward trend.Comparing the flows of the biogas stream, the following can be observed:- the intensity of biogas production for lignite (smaller bed), there is a greater phase exchange, because the bed layout provides more space for the adhesion of methanogenic microorganisms, - in turn, in the case of lignite (flat fragments of the deposit), there is less phase exchange, i.e. less biogas production.The performed rheological tests of pig slurry proved the foaming properties of the sub-strate at 25 °C and 500 rpm for a kinematic viscosity of 27.5 mPa. Characteristic foaming properties are manifested by the polydisperse system, which is pig slurry.