Anaerobic Digester Syngas Bioconversion via Jet Ejector
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Anaerobic digesters face limitations in maximizing methane production from complex organic substrates, and the energy content in digestate is not fully utilized, leading to inefficiencies in wastewater treatment and energy recovery.
Innovation Solution
Introducing syngas produced from pyrolysis or gasification of biomass or digestate into anaerobic digesters using a jet ejector pump system to enhance gas-liquid mass transfer, allowing for increased methane production and energy recovery through bioconversion of CO and H2 into methane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If syngas is introduced into anaerobic digesters to enhance methane production, then energy recovery and methane production increase, but the complexity of the system increases due to integration of pyrolysis/gasification units and jet ejector pumps
Solution Approach 1:
The patent combines multiple waste treatment processes (pyrolysis, gasification, and anaerobic digestion) into an integrated system where digestate is converted to syngas and then reintroduced to the digester, creating a coupled system that enhances methane production while managing waste streams efficiently
Solution Approach 2:
The jet ejector pump serves as an intermediary device that facilitates the transfer of syngas from the pyrolysis/gasification unit to the anaerobic digester, enabling mass transfer without requiring complex piping or pressure control systems
2Productivity
If jet ejector pump is used to transfer syngas into digestate, then gas-liquid mass transfer efficiency improves, but energy consumption increases due to the pumping operation
Solution Approach 1:
The jet ejector pump utilizes hydraulic principles where high-velocity liquid or gas flow creates a vacuum to draw in and mix syngas with digestate, achieving efficient mass transfer through fluid dynamics rather than mechanical mixing
Solution Approach 2:
The system leverages the phase transition and expansion characteristics of gases when introduced to liquid digestate, using the jet ejector to create conditions where syngas dissolves and reacts efficiently in the liquid phase
3Loss of energy
If digestate is pyrolyzed or gasified to produce syngas, then energy content in digestate is utilized, but additional equipment and process steps are required
Solution Approach 1:
The system uses the digestate itself as fuel for pyrolysis/gasification, and the resulting syngas is fed back to the digester to produce additional methane, creating a self-sustaining energy cycle where waste materials are converted into energy resources
Solution Approach 2:
The integrated system performs multiple functions: waste stabilization through anaerobic digestion, energy recovery through pyrolysis/gasification, and enhanced methane production through syngas bioconversion, making the facility multi-functional and efficient
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases methane production in digesters and enables efficient energy recovery by converting syngas into methane, which can be used as a fuel, while also producing biochar that can be used as a soil enhancer, thereby reducing waste and energy consumption.
Implementation Method 1
Introducing syngas produced from pyrolysis or gasification of biomass or digestate into anaerobic digesters using a jet ejector pump system to enhance gas-liquid mass transfer
Implementation Method 2
anaerobic digestion produces biogas as a result of the biological fermentation of volatile solids (VS) supplied with the feedstock
Implementation Method 3
allowing for increased methane production and energy recovery through bioconversion of CO and H2 into methane
Implementation Method 4
Pyrolysis is a technique typically used to process solid waste such as wood chips or sawdust. Pyrolysis produces biochar, liquids and gases from a biomass by heating the biomass in a low or no oxygen environment
Implementation Method 5
High temperature pyrolysis is also known as gasification, and produces primarily synthesis gas
Data Source
AI summary
An anaerobic digester is fed a feedstock, for example sludge from a municipal wastewater treatment plant, and produces a digestate. The digestate is dewatered into a cake. The cake may be dried further, for example in a thermal drier. The cake is treated in a pyrolysis system to produce a synthesis gas and biochar. The gas is sent to the same or another digester to increase its methane production. The char may be used as a soil enhancer.