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Bridging the gap between the lab and full-scale: The Chimera

Edgar Blanco - Managing Director & Head Designer

If you have spent days and nights following live AD plant biogas flow and composition data (CH4 and CO2) to assess the state of the process, then you know the value of biogas flow and composition as a live, fast indicator of conditions in the digester that can be accessed remotely 24/7. A few may have access to online pH and even fewer have online VFA analysis to further assess process status, but %CH4 is perhaps the first indicator we look at. Is a recent change in loading improving or worsening AD plant conditions? Is the system responding to changes such as re-inoculation or temperature control? Should I increase or reduce loading? Part of the answer to these questions is based on evaluation of changes in gas composition. For most operators, live gas flow and composition are the first, most dynamic and effective monitoring tools in our armoury.
In parallel to operating a full-scale AD plant, we also operated lab-scale digesters and, searching for gas analysers for our lab reactors, we were surprised by the limited options and capabilities available. Some equipment allowed real-time monitoring of flow and composition testing from gas stored in bags; others enable continuous monitoring of composition with spot measurement of flow (manometric systems), others complex and expensive, but none of the systems in the market enable near continuous monitoring of gas composition and gas flow. Some allow continuous flow measurement of CH4 but stripping other important elements from the biogas (alkaline washing which wipes out CO2, H2S). The ultimate option is the expensive and complex gas chromatography together with gas flow, something almost no AD research labs can afford to do on continuous mode. 
Measuring gas composition: Industrial AD vs Lab capability
In terms of day-to-day process monitoring and optimisation, it is paradoxical that even the most basic AD plants had better capabilities than most of the AD research labs in the world. What AD plants seldom have is scientists to interpret the operational data on a day-to-day basis. On the other hand, many research institutions have the scientists but could not afford the
continuous monitoring capabilities for their lab-scale research reactors. Enabling researchers to replicate AD plant conditions and be able to monitor with frequency more akin to that of industry can speed up development of AD and lead to new valorisation paths, enhancing the exchange of expertise between academic research and the industrial sectors.
Key requirements: small gas samples, reliable, online analysis at low cost.

%CH₄ and %CO₂ for AD plant control

Development of low flow gas composition analyser for lab reactors
We operated our lab auto-fed digesters in parallel to a full-scale AD plant for seven years. We analysed gas composition daily using gas bags and hand-held instruments. This provided some data for dynamic analysis of the process but was laborious and still limited data granularity. Anaero embarked on a project to develop our own analyser capable of more regular analysis for small gas volumes (<100ml samples). We found quality sensors, but these, despite their characteristics were not suitable for our small sample volume requirements. After years of testing and modifications we have completed our multi-channel gas monitor using a combination of non-dispersive near infrared sensors (NDIR), and
electrochemical cell sensors (expansion) that enable users to measure up to 8 gases (CH4 and CO2, etc) for up to 15 different sources with flows as low as 50ml/hour. Chimera gas analyser measures up to 15 different gas lines. Biogas or/and flushing flow into a restricted volume manifold where gas is automatically sent to sensor arrays or diverted for storage in gas bags or discharge: two functions, continuous measurement and optional storage of excess gas. Available sensors include CH4, CO2, CO, N2O, H2, H2S, NH3, and O2, other gases will be added the options later. Our technology has been granted a PCT patent WO 2024/134129 and more advances has been added!
Additionally, the Chimera Gas Analyser allows gas storage so other analysis of gas can be carried out.
Chimera can also be used with batch digesters from other brands in the market. After gas flow measurement from any other brand digester systems, you simply connect gas lines to Chimera and that’s all, you can then upgrade any such system now to automatic gas composition with Anaero Technology’s Chimera! Anaero is also developing a more “rugged” version for outdoor use suitable for sludge treatment, wastewater treatment, energy crops, fermentation, landfilling RNG, environmental monitoring, and even for composting users!
Beyond gas monitoring...
Chimera analysers enable AD researchers to monitor the gas composition of their lab digesters automatically, in continuous mode, and can also be adapted for remote access, enabling the lab to have comparable gas data granularity to that of AD plants.
We are researchers and developers, could we ignore the new realities of AI and robotics? No! So, we have also packed our Chimera with capabilities to take reads from two digital channels and incorporated a Raspberry Pi computer capable or processing the gas data and running AI models with the data collected by the sensors. It can then be programmed to send commands to other equipment, such as reducing feed if CH4 is lower than X %. You can also let Chimera run AI models to autonomously control dosing pumps or feeding pumps to reactors either via MODBUS communication or following MQTT protocols directly from Raspberry both well established industrial control protocols.
Anaero Technology have decided to make Chimera not just a gas analyser, but a process monitor and control instrument to enable researchers from generating status alarms automatically, to begin to test and apply artificial intelligence to anaerobic digestion and fermentation research. Our aim:  to aid the optimisation of current AD and fermentation technology and contribute to novel developments in the fields of bioenergy, fermentation, and environmental monitoring.
Chimera is the product of over 10 years of development by over 14 people in three different continents, the story of modern times! If you are interested in exploring how Chimera might assist your work don’t hesitate to contact us.
1.07.2025

©2024 by Anaero Technology

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