Process Simulation and Optimization of Anaerobic Co-Digestion

Anaerobic digestion (AD) is an established method that has been extensively utilized for waste management, waste treatment, and biogas production. Anaerobic co-digestion (AcoD) is regarded as a practical approach to address substrate characteristics and system optimization issues. The distinction between AcoD and mono-digestion is that AcoD has a higher organic loading and significant substrate composition variation. There are many factors involved in AcoD which affect the biogas plant’s production ability and performance. Using response surface methodology (RSM) to forecast the optimal conditions for maximum biogas output, this article provides an overview of the different operational parameters in the AcoD process, modeling of the AcoD process, and overall process optimization. Standard software used for AcoD process simulation are Aspen Plus, SuperPro Designer, BioWin, CFD, and MATLAB. Review addresses design, development, and optimization frameworks for biogas production systems that take numerous aspects into account. The most significant AcoD optimization parameters include temperature, co-substrate concentration, inoculum ratio (percent), and C/N ratio.

Effect of chopping straw on the intensity of biogas output

Straw has a high energy capacity, but it is not ideal for the operation of biogas plants, since it contains a large amount of nitrogen-free substances, and only 4-6% nitrogen and mineral salts, but if it is properly pretreated, it is possible to reduce the fermentation time and increase the biogas yield. The positive results of pretreatment of biological raw materials are a high degree of grinding and homogenization of raw materials; reduction of the biomass fermentation period; the release of natural enzymes that are biological catalysts for the fermentation of biomass; stabilization of biological processes, which leads to the absence of foam and floating crust in the upper part of the bioreactor; the percentage of methane in biogas increases to 70-75 %. The aim of the study is to determine the intensity of methane fermentation of crushed buckwheat, rapeseed, soybean straw and corn stalks, depending on the size of crushed particles and the method of grinding. The article discusses the issue of determining the dynamics of biogas output depending on the method and geometric dimensions of grinding buckwheat straw, soybeans, rapeseed and corn chaff in a mesophilic mode of fermentation. The following devices were used to prepare the straw: shears, hammer mill, feed chopper and extruder. Additionally, soaking was carried out in water at a certain temperature. The prepared biomass together with the seed in a ratio of 1: 4 was put into laboratory fermenter bags and a thermostat. The biogas yield was measured for 42 days using special methods, which are patented in Ukraine. Based on the measurement results, graphs were built that characterize the dynamics of biogas output.

Overview of AD

There are many methodologies for improving the biogas output from anaerobic digestion. These techniques include physical (e.g., gas production and feedstock parameters), reactor configuration and chemical parameters (e.g., pH and volatile fatty acid concentrations) within the digester can help to link particular functions and features of the process. Using this expanse of data, mathematical models can be used to understand and forecast the biological process within an anaerobic digester. Such models can then be further developed on a process and biological level to improve their ability to mimic the function of the reactor. This chapter will provide background into modelling and reactor configuration in order to obtain a digital twin of an anaerobic digester.

Uses of Biogas and Biomethane

BioCH4 is the only established renewable energy fuel source currently directly applicable in all sectors (i.e., electricity, heat and transport fuel). It is easily processed and suitable for versatile power generation in cogeneration plants. Biogas, from which bioCH4 is most widely produced, and thus bioCH4 is a valuable supplier to the energy and transport fuel markets and can be easily incorporated into renewable energy systems. The natural gas grid storage capacity can be used and heat demand can be met regardless of the location and time of biogas output. Using bioCH4 in cogeneration plants and as fuel in gas-powered vehicles contributes to an especially high potential contribution to rising greenhouse gas emissions. This chapter gives an overview of the potential uses for biogas and bioCH4 as a renewable low-CO2 fuel.

The use of the Mephosphon drug to accelerate the process of biogas output and ripening of organic wastes

This article discusses a new method for the reclamation of organic waste into biogas with the addition of the biologically active additive Mephosphon to the substrate to accelerate the process of obtaining biogas (decomposition) and preserving nutrient elements in the final product. The study object was cow manure from a private farm household. The experiments were carried out for 10 days in a lowvolume biogas unit (LVBU) without airtight in a heat-insulated reactor filled with 2/3 cow manure. The use of the Mephosphon drug in ultra-low concentrations (10-4) allowed us to obtain a useful product in the form of high-quality organic fertilizer and biogas.

Experimental determination of the influence of a constant electric field on the output of biogas and substrate varieties

Оbjective. To investigate the effectiveness of stimulation of biogas release from cow substrate under influence of constant electric field of certain tension at mesophilic temperature regime. Methodology. Experimental research based on a laboratory biogas plant consisting of two reactors housed inside a thermostat and connected to gas-holder system to determine its volume and chemical composition. One of the reactors is equipped with a system of exposure to substrate by constant electric field. The optimum intensity of electric field was determined by previous experiments. The research was performed on a cow's substrate under mesophilic regimen and included determination of the dynamics of biogas output, changes in its chemical composition, and overall degree of dry organic matter destruction. Findings. The research has shown that biogas output per unit of dry organic matter under influence of constant electric field increased by 11.3%, the destruction of the latter increased by 12.2%, and the total volume of biogas (excluding CO2) increased by 8, 2%. It should also be noted that the lag phase was reduced by 12.2%. Originality. Complex research of influence of constant electric field on biomethanogenesis with measurement of chemical composition of obtained biogas and determination of degree of dry organic matter destruction has not been conducted before. Practicalvalue. The work allowed us to conclude that the influence of constante lectric field of certain intensity really stimulates the process of biogas production, without significantly affecting its composition. This method of biome-?hanogenesis intensification can be applied in industrial plants to increase their efficiency. Keywords: biogas, biomethanogenesis, bioenergy, biogasplant, chemical composition

The Future Agricultural Biogas Plant in Germany: A Vision

After nearly two decades of subsidized and energy crop-oriented development, agricultural biogas production in Germany is standing at a crossroads. Fundamental challenges need to be met. In this article we sketch a vision of a future agricultural biogas plant that is an integral part of the circular bioeconomy and works mainly on the base of residues. It is flexible with regard to feedstocks, digester operation, microbial communities and biogas output. It is modular in design and its operation is knowledge-based, information-driven and largely automated. It will be competitive with fossil energies and other renewable energies, profitable for farmers and plant operators and favorable for the national economy. In this paper we discuss the required contribution of research to achieve these aims.

Modelling of Two-Stage Methane Digestion With Pretreatment of Biomass

Systems of anaerobic digestion should be used for processing of organic waste. Managing the process of anaerobic recycling of organic waste requires reliable predicting of biogas production. Development of mathematical model of process of organic waste digestion allows determining the rate of biogas output at the two-stage process of anaerobic digestion considering the first stage. Verification of Konto’s model, based on the studied anaerobic processing of organic waste, is implemented. The dependencies of biogas output and its rate from time are set and may be used to predict the process of anaerobic processing of organic waste.