This research project enables further development and improvement of the mixing efficiency in an existing biogas plant, by utilizing CFD simulation as well as a newly developed flow sensor in addition to supportive laboratory tests. The flow was analyzed considering the following variables: The mixing time, the Dry Matter (DM) content, the positioning of the agitators and how it can be related to the amount of velocity dead-zones.
The velocity measurements took place at the biogas plant of the company Ardestorfer Bioenergie GmbH in the district of Buxtehude. The current plant capacity is approximately 1.6 MWel using animals manure, energy crops as well as agricultural residuals.
In order to be able to perform the CFD simulation, a complete 3D model had to be done of the examined fermenter and the mixing agitators. Moreover, the current setup including fluid properties, boundary and initial conditions had to be taken into consideration. Velocity measurements were used as a validation approach for the simulation results, furthermore to acquire an overview of the flow behavior over the investigated mixing period.
Firstly, it was found that at higher DM content the flow seemed to be more stable, and the velocity values get quite higher at the examined points. Moreover, at higher DM content (9.35% compared with 8.8%) the velocity dead-zones seemed to be approximately 70% less.
Secondly, another approach was considered to improve the mixing and to minimize the dead-zones by changing the position of the main agitator. The new scenario showed fewer dead-zones by approximately 65% according to the CFD model.
Thirdly, at all scenarios and setups, the flow seemed to reach the maximum possible velocity, and rather motion distribution after 150-180 seconds. Showing no remarkable improvement after this period.
The mentioned findings were concluded based on comparisons between different velocity measurements as well as CFD simulation results at different operating conditions and setups. Being able to offer proper recommendations for a better energy efficiency in terms of lower energy consumption and better mixing all over the fermenter.
Inhaltsverzeichnis (Table of Contents)
- CHAPTER 1: INTRODUCTION
- 1.1 BENEFITS OF BIOGAS
- 1.1.1 RENEWABLE ENERGY SOURCE
- 1.1.2 REDUCING GREENHOUSE GAS EMISSIONS
- 1.1.3 WASTE REDUCTION
- 1.2 BIOGAS IN GERMANY
- 1.4 ARDESTORF BIOGAS PLANT
- 1.5 PROJECTS OBJECTIVES
- CHAPTER 2: BACKGROUND AND LITERATURE REVIEW
- 2.1 BIOGAS TECHNOLOGY (ANAEROBIC DIGESTION)
- 2.2 THE BIOCHEMICAL PROCESS OF AD
- 2.2.1 HYDROLYSIS
- 2.2.2 ACIDOGENESIS
- 2.2.3 ACETOGENESIS
- 2.2.4 METHANOGENESIS
- 2.3 SUBSTRATES FOR THE ANAEROBIC DIGESTION
- 2.4 ANAEROBIC DIGESTION PARAMETERS
- 2.4.1 TEMPERATURE
- 2.4.2 HYDRAULIC RETENTION TIME (HRT)
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This research project aimed to improve the mixing efficiency of an existing biogas plant using CFD simulation and a newly developed flow sensor, complemented by laboratory tests. The study analyzed the impact of Dry Matter (DM) content and agitator positioning on mixing time and the presence of velocity dead-zones.
- Optimization of biogas plant mixing efficiency
- Impact of Dry Matter content on flow dynamics
- Influence of agitator positioning on mixing performance
- Validation of CFD simulation results through velocity measurements
- Recommendations for improved energy efficiency
Zusammenfassung der Kapitel (Chapter Summaries)
CHAPTER 1: INTRODUCTION: This chapter introduces the benefits of biogas as a renewable energy source, emphasizing its role in reducing greenhouse gas emissions and waste. It provides context by discussing the biogas industry in Germany and specifically focusing on the Ardestorfer Bioenergie GmbH biogas plant, the subject of the study. The chapter concludes by outlining the project's objectives, setting the stage for the subsequent analysis of flow and mixing optimization within the plant.
CHAPTER 2: BACKGROUND AND LITERATURE REVIEW: This chapter provides a comprehensive overview of biogas technology, focusing on the anaerobic digestion process. It details the biochemical stages involved—hydrolysis, acidogenesis, acetogenesis, and methanogenesis—and explores the various substrates used in anaerobic digestion. Crucially, it examines key parameters influencing anaerobic digestion, namely temperature and hydraulic retention time (HRT), laying a strong foundation for understanding the factors affecting the efficiency of the biogas plant under investigation. The review establishes the theoretical framework within which the experimental and simulation work is conducted.
Schlüsselwörter (Keywords)
Biogas, CFD simulation, mixing efficiency, anaerobic digestion, velocity measurements, Dry Matter content, agitator positioning, velocity dead-zones, renewable energy, energy efficiency.
Frequently Asked Questions: Biogas Plant Mixing Efficiency Optimization
What is the main focus of this research project?
This research project focuses on improving the mixing efficiency of an existing biogas plant. This is achieved through the use of Computational Fluid Dynamics (CFD) simulation, a newly developed flow sensor, and laboratory tests. The project analyzes how Dry Matter (DM) content and agitator positioning affect mixing time and the presence of velocity dead zones.
What are the key objectives of the research?
The key objectives include optimizing biogas plant mixing efficiency, analyzing the impact of Dry Matter content on flow dynamics, determining the influence of agitator positioning on mixing performance, validating CFD simulation results via velocity measurements, and providing recommendations for improved energy efficiency.
What are the key themes explored in the research?
The key themes revolve around optimizing biogas production by improving the mixing process within the biogas plant. This involves investigating the influence of various factors, including the amount of dry matter in the substrate and the optimal placement of the agitator, on the overall efficiency of the anaerobic digestion process.
What is the anaerobic digestion process, and how is it relevant to this research?
Anaerobic digestion is the process by which microorganisms break down organic matter in the absence of oxygen to produce biogas. This research investigates this process by analyzing the different stages (hydrolysis, acidogenesis, acetogenesis, and methanogenesis) and how parameters like temperature and hydraulic retention time impact its efficiency. The findings directly relate to optimizing the mixing process within the biogas plant to improve the overall anaerobic digestion.
What methods were used in this research?
The research utilized a combination of methods: Computational Fluid Dynamics (CFD) simulation to model flow dynamics, a newly developed flow sensor for velocity measurements, and laboratory tests to validate the simulation results. These methods allowed for a comprehensive analysis of the biogas plant's mixing efficiency under different conditions.
What specific biogas plant is this research focused on?
The research focuses on the Ardestorfer Bioenergie GmbH biogas plant in Germany.
What are the benefits of biogas as highlighted in the research?
The research highlights biogas as a renewable energy source that reduces greenhouse gas emissions and contributes to waste reduction.
What are the key parameters influencing anaerobic digestion?
Key parameters influencing anaerobic digestion that are explored in this research include temperature and hydraulic retention time (HRT).
What are the chapter summaries provided in the document?
Chapter 1 provides an introduction to biogas, its benefits, and the specific objectives of the research concerning the Ardestorfer plant. Chapter 2 offers a comprehensive literature review on anaerobic digestion, encompassing its biochemical stages, substrates used, and influencing parameters, thereby establishing a theoretical framework for the subsequent experimental and simulation work.
What are the keywords associated with this research?
The keywords include: Biogas, CFD simulation, mixing efficiency, anaerobic digestion, velocity measurements, Dry Matter content, agitator positioning, velocity dead-zones, renewable energy, and energy efficiency.
- Quote paper
- Obada Yaghi (Author), 2016, Flow and Mixing Optimization of an Existing Biogas Plant through CFD Simulation and Velocity Measurements Prepared, Munich, GRIN Verlag, https://www.grin.com/document/460934
