scholarly journals Modelling of Demand Driven Biogas Plants to Cover Residual Load Rises

Proceedings ◽  
2018 ◽  
Vol 2 (22) ◽  
pp. 1385 ◽  
Author(s):  
Lena Peters ◽  
Piotr Biernacki ◽  
Frank Uhlenhut ◽  
Sven Steinigeweg

In future, systems for energy storage and demand-driven energy production will be essential to cover the residual load rises. A rigorous dynamic process model based on ADM1 was used to analyze the flexible operation of biogas plants for covering the residual load rises. This model was optimized and an operation concept for a demand-driven energy production was worked out. For the input data different substrates were analyzed by batch fermentations and the Weender analysis with van Soest method. The results show that the substrates have got a different biogas production rate and reaction time. Finally, an intelligent feeding algorithm by implementation of a PI controller was developed. It calculates feeding times and quantities of available substrates so that a defined energy demand can be covered by biogas plants. The results demonstrate that a flexible operation of biogas plants with an individual and intelligent feeding program is possible.

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5755
Author(s):  
Adam Wąs ◽  
Piotr Sulewski ◽  
Vitaliy Krupin ◽  
Nazariy Popadynets ◽  
Agata Malak-Rawlikowska ◽  
...  

Renewable energy production is gaining importance in the context of global climate changes. However, in some countries other aspects increasing the role of renewable energy production are also present. Such a country is Ukraine, which is not self-sufficient in energy supply and whose dependency on poorly diversified import of energy carriers regularly leads to political tensions and has socio-economic implications. Production of agricultural biogas seems to be a way to both slow down climatic changes and increase energy self-sufficiency by replacing or complementing conventional sources of energy. One of the most substantial barriers to agricultural biogas production is the low level of agricultural concentration and significant economies of scale in constructing biogas plants. The aim of the paper was thus to assess the potential of agricultural biogas production in Ukraine, including its impact on energy self-sufficiency, mitigation of greenhouse gas (GHG) emissions and the economic performance of biogas plants. The results show that due to the prevailing fragmentation of farms, most manure cannot be processed in an economically viable way. However, in some regions utilization of technically available manure for agricultural biogas production could cover up to 11% of natural gas or up to 19% of electricity demand. While the theoretical potential for reducing greenhouse gas emissions could reach 5% to 6.14%, the achievable technical potential varies between 2.3% and 2.8% of total emissions. The economic performance of agricultural biogas plants correlates closely with their size and bioenergy generation potential.


Energies ◽  
2017 ◽  
Vol 10 (11) ◽  
pp. 1822 ◽  
Author(s):  
Emma Lindkvist ◽  
Maria Johansson ◽  
Jakob Rosenqvist

2020 ◽  
pp. 136-148
Author(s):  
M. Spodoba ◽  
◽  
M. Zablodskiy ◽  

To date, biomass fermentation in biogas plants is one of the most advanced, environmentally and economically viable solutions for energy production from waste. However, the process of anaerobic fermentation of waste is long, so one of the main ways to intensify biogas production is mixing and heating of biomass during fermentation. The article is devoted to the question of substantiation of creation of electrothermomechanical system for mixing and heating of biomass in a biogas reactor. The combination of two intensification processes in a combined system pays special attention to the energy efficiency of such a system, so the creation of the system requires in-depth study of heat fluctuations from speed and the presence of a contaminant layer on the heater surface and determine the optimal stirrer speed. The studies were performed for a cylindrical biogas reactor, assuming that the contaminant layer is evenly distributed on the surface of the blades and the shaft in which the electric heaters are installed. When determining the optimal frequency of biomass mixing, the criterion of optimality was taken to be the smallest value of the difference between the heat flux of the contaminated and uncontaminated surface of the heater. During the study it was found that at speed , the difference between the heat flux of the contaminated surface and uncontaminated is 40 %. At speed , the difference between the values is 26%. According to the selected optimality criterion, the optimal speed of the electrothermomechanical system taking into account the contaminant layer is in the range . The increase in heat flux from the stirring frequency is non-linear for both contaminated and non-contaminated heaters.


2020 ◽  
Author(s):  
Jacob Joseph Lamb

In municipalities and rural areas, biogas is a growing form of energy production and is also a feasible waste management option. Biogas manufacturing, in terms of environmental life cycle assessments, appears to have a remarkable opportunity to mix fertilizer recovery with energy generation utilizing different underused methods including urban biowastes or manure. Biogas production life cycle assessments suggest benefits such as CO2 reductions and chemical fertilizer replacement. Established biogas plants have specific biogas processing activities and life-cycle effects are affected by regulations, environmental conditions and biogas production objectives. This chapter describes and examines important biogas problems.


2019 ◽  
Vol 23 (3) ◽  
pp. 57-69 ◽  
Author(s):  
Fosca Conti ◽  
Abdessamad Saidi ◽  
Markus Goldbrunner

Abstract Cut in greenhouse gas emissions, increment of energy from renewables and improvement in energy efficiency represent the three key targets for future energy systems. Among the available bioenergy technologies, biogas production via biodegradation and anaerobic digestion is a widely applied approach, not only to produce biofuels but also to manage industrial and domestic organic waste. Within the biogas production, a sufficient mixing of the organic mass is a crucial step to ensure high biogas yields by bacteria and enzymes. Measurements of the electric power consumption of biogas plants revealed that the electrical energy demand of the stirrer system has a high share of the total electricity consumption of a biogas plant. Investigations on real biogas digesters to optimize the mixing process are cost and time intensive. Therefore, laboratory prototypes and computational simulations represent promising alternatives to analyse and improve the efficiency of mixing systems. In this paper, a computational fluid dynamics (CFD) model is presented, which is applied to commercial stirring systems. The case of two propeller stirrers, located in diametrically opposite positions in a tank filled with ca. 1400 m3 of substrate is described in detail. For the simulation, the rheology of the fluid is adapted to a biomass with 12 wt % dry matter content and obeying the non-Newtonian generalized Ostwald-de Waele power law. The developed simulation procedure considers the rotation angle of each propeller and its height. A total of 441 mixing configurations are calculated and evaluated in terms of the technical benefit. The investigation reveals that locations of the rotors far away from the bottom and high rotational angles cause advantageous fluid dynamics.


Author(s):  
Luděk Kamarád ◽  
Stefan Pohn ◽  
Günther Bochmann ◽  
Michael Harasek

The total electricity demand of investigated biogas plants (BGP) makes up 7–8 % of the total electricity produced. Nearly 40 % of this energy is consumed just for mixing in digesters and the energy demand for mixing in some biogas plants can be even higher. Therefore, optimal mixing in anaerobic digesters is a basic condition for efficient plant operation and biogas production. The use of problematic substrates (e.g. grass silage or other fibrous substrates), installation of unsuitable mixing systems or inconvenient mixing intervals may lead to mixing problems. Knowledge about mixing in biogas digesters is still insufficient, so the objective of this study was to fill the information gaps in the literature by determining the minimal retention time of substrates fed into anaerobic digesters and to describe substrate distribution and washing out rates from investigated digesters. Two full-scale biogas plant digesters (2000 m3 and 1500 m3) using different mixing systems and substrates were investigated. To characterize the substrate distribution, lithium hydroxide monohydrate solutions were used for tracer tests at concentrations of 47.1 mg Li+ / kg TS and 46.6 mg Li+ / kg TS in digester. The tracer concentration in the digester effluents was measured during two hydraulic retention times and compared. Although the tracer was detected in the digester effluent at nearly the same time in both cases, the tracer tests showed very different distribution curves. The tracer concentration in effluent B grew much slower than in effluent A and no significant short circuiting streams were detected. Although the data calculated by computational fluid dynamics methods (CFD) showed a very good agreement with the full scale results, full comparison was not possible.


Author(s):  
Kai Schumüller ◽  
Dirk Weichgrebe ◽  
Stephan Köster

AbstractTo tap the organic waste generated onboard cruise ships is a very promising approach to reduce their adverse impact on the maritime environment. Biogas produced by means of onboard anaerobic digestion offers a complementary energy source for ships’ operation. This report comprises a detailed presentation of the results gained from comprehensive investigations on the gas yield from onboard substrates such as food waste, sewage sludge and screening solids. Each person onboard generates a total average of about 9 kg of organic waste per day. The performed analyses of substrates and anaerobic digestion tests revealed an accumulated methane yield of around 159 L per person per day. The anaerobic co-digestion of sewage sludge and food waste (50:50 VS) emerged as particularly effective and led to an increased biogas yield by 24%, compared to the mono-fermentation. In the best case, onboard biogas production can provide an energetic output of 82 W/P, on average covering 3.3 to 4.1% of the total energy demand of a cruise ship.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2424
Author(s):  
Jan Martin Zepter ◽  
Jan Engelhardt ◽  
Tatiana Gabderakhmanova ◽  
Mattia Marinelli

Biogas plants may support the transformation towards renewable-based and integrated energy systems by providing dispatchable co-generation as well as opportunities for biogas upgrading or power-to-X conversion. In this paper, a simulation model that comprises the main dynamics of the internal processes of a biogas plant is developed. Based on first-order kinetics of the anaerobic digestion process, the biogas production of an input feeding schedule of raw material can be estimated. The output of the plant in terms of electrical and thermal energy is validated against empirical data from a 3-MW biogas plant on the Danish island of Bornholm. The results show that the model provides an accurate representation of the processes within a biogas plant. The paper further provides insights on the functioning of the biogas plant on Bornholm as well as discusses upgrading potentials of biogas to biomethane at the plant from an energy perspective.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2282
Author(s):  
Sanjeet Mehariya ◽  
Rahul Kumar Goswami ◽  
Pradeep Verma ◽  
Roberto Lavecchia ◽  
Antonio Zuorro

The increasing world population generates huge amounts of wastewater as well as large energy demand. Additionally, fossil fuel’s combustion for energy production causes the emission of greenhouse gases (GHG) and other pollutants. Therefore, there is a strong need to find alternative green approaches for wastewater treatment and energy production. Microalgae biorefineries could represent an effective strategy to mitigate the above problems. Microalgae biorefineries are a sustainable alternative to conventional wastewater treatment processes, as they potentially allow wastewater to be treated at lower costs and with lower energy consumption. Furthermore, they provide an effective means to recover valuable compounds for biofuel production or other applications. This review focuses on the current scenario and future prospects of microalgae biorefineries aimed at combining wastewater treatment with biofuel production. First, the different microalgal cultivation systems are examined, and their main characteristics and limitations are discussed. Then, the technologies available for converting the biomass produced during wastewater treatment into biofuel are critically analyzed. Finally, current challenges and research directions for biofuel production and wastewater treatment through this approach are outlined.


2018 ◽  
Vol 4 (4) ◽  
pp. 59 ◽  
Author(s):  
Judith González ◽  
Marta Sánchez ◽  
Xiomar Gómez

Anaerobic digestion is a well-known technology which has been extensively studied to improve its performance and yield biogas from substrates. The application of different types of pre-treatments has led to an increase in biogas production but also in global energy demand. However, in recent years the use of carbon conductive materials as supplement for this process has been studied resulting in an interesting way for improving the performance of anaerobic digestion without greatly affecting its energy demand. This review offers an introduction to this interesting approach and covers the different experiences performed on the use of carbon conductive materials proposing it as a feasible alternative for the production of energy from biomass, considering also the integration of anaerobic digestion and thermal valorisation.


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