scholarly journals Methodology for Analysing Energy Demand in Biogas Production Plants—A Comparative Study of Two Biogas Plants

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


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.


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.


2018 ◽  
Vol 8 (11) ◽  
pp. 2083 ◽  
Author(s):  
Magdalena Muradin ◽  
Katarzyna Joachimiak-Lechman ◽  
Zenon Foltynowicz

Implementation of the circular economy is one of the priorities of the European Union, and energy efficiency is one of its pillars. This article discusses an effective use of agri-food industry waste for the purposes of waste-to-energy in biogas plants. Its basic objective is the comparative assessment of the eco-efficiency of biogas production depending on the type of feedstock used, its transport and possibility to use generated heat. The environmental impact of the analysed installations was assessed with the application of the Life Cycle Assessment (LCA) methodology. Cost calculation was performed using the Levelized Cost of Electricity (LCOE) method. The LCA analysis indicated that a biogas plant with a lower level of waste heat use where substrates were delivered by wheeled transport has a negative impact on the environment. The structure of distributed energy production cost indicates a substantial share of feedstock supply costs in the total value of the LCOE ratio. Thus, the factor affecting the achievement of high eco-efficiency is the location of a biogas plant in the vicinity of an agri-food processing plant, from which the basic feedstock for biogas production is supplied with the transmission pipeline, whereas heat is transferred for the needs of production processes in a processing plant or farm.


Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5374
Author(s):  
Robert Bedoić ◽  
Goran Smoljanić ◽  
Tomislav Pukšec ◽  
Lidija Čuček ◽  
Davor Ljubas ◽  
...  

Crop-based biogas energy production, in combination with electricity generation under subsidy schemes, is no longer considered a favourable business model for biogas plants. Switching to low-cost or gate fee feedstocks and utilising biogas via alternative pathways could contribute to making existing plants fit for future operations and could open up new space for further expansion of the biogas sector. The aim of this study was to combine a holistic and interdisciplinary approach for both the biogas production side and the utilisation side to evaluate the impact of integrating the biogas sector with waste management systems and energy systems operating with a high share of renewable energy sources. The geospatial availability of residue materials from agriculture, industry and municipalities was assessed using QGIS software for the case of Northern Croatia with the goal of replacing maize silage in the operation of existing biogas plants. Furthermore, the analysis included positioning new biogas plants, which would produce renewable gas. The overall approach was evaluated through life cycle assessment using SimaPro software to quantify the environmental benefits and identify the bottlenecks of the implemented actions. The results showed that the given feedstocks could replace 212 GWh of biogas from maize silage in the relevant region and create an additional 191 GWh of biomethane in new plants. The LCA revealed that the proposed measures would contribute to the decarbonisation of natural gas by creating environmental benefits that are 36 times greater compared to a business-as-usual concept. The presented approach could be of interest to stakeholders in the biogas sector anywhere in the world to encourage further integration of biogas technologies into energy and environmental transitions.


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