At the heart of our system is a set of continuously stirred reactors, each one constructed as an integral unit making it easy to handle and manipulate.
The reactor is a robust HDPE vessel with an easily assembled gas-tight push fit lid on which is mounted the geared motor and stirring mechanism.
All reactor parts are A2 grade stainless or inert plastic and can be easily serviced with available spare parts.
Each set has eight reactors allowing you to run e.g. a pair of blank controls alongside 3 duplicates of samples. The system is of expandable by adding another set of 8 reactors which connect to the same data acquisition system (DAS), so more samples can be tested using the same controls. The data analysis program can accept results from any number of sets and is only restricted by the number of different samples (a-z) that can be entered in the data entry table.
The reactors are housed in a tough rota-moulded polypropylene water bath into which a 60mm diameter thermostatic heater can be inserted to maintain temperature.
The reactors themselves simply fit into their slots, and are powered from a bridge that spans the water bath. The reactors can be used to carry out biochemical methane potential (BMP), residual biogas potential (RBP) tests, or for research and development. The simple design makes the setting up of tests a rapid and easily performed task.
The gas counters use the ‘tipping bucket’ principle first described for this type of flow measurement application by the Water Research Centre (WRC) in the UK.
We have taken this design and used CPD principles to ensure precision and accuracy in the manufacture of the components. This has produced a seamless leak-proof vessel to house the measuring bucket, which itself is manufactured to high tolerance specifications. The gas tight lid allows the off gases to be collected in a gas-sampling bag for compositional analysis or to confirm the volume by measurement in a water displacement gasometer.
The bucket volume has been kept small (around 6ml) to improve the accuracy of the test, as daily gas production can be very low towards the end of a run.
All parts of the system are sealed, and data is captured non-intrusively and sent to the data acquisition system by a single cable: this simplifies cable management and ensures a non-cluttered workspace.
Our data acquisition system (DAS) uses state of the art ARM technology which is at the heart of most mobile communications technology.
Our software development team has developed a simple, intuitive, interactive interface with all necessary functions carried out using drop-down lists and menu bars in a touch screen environment.
We use the processing power of a 64bit chipset to do all the necessary logging and data manipulation so that each time a gas counter tips, the bucket volume is corrected to standard temperature and pressure. This takes into account the relative buoyant density of the gas based on its likely composition. The unit also plots the data allowing you to see the progress of the test.
The DAS will connect to Wi-Fi and can store data on your network, email it to you automatically each day or on demand, or you can download it to a USB memory stick.
The risk of mid-process data loss is minimised as in the event of a power failure the system will reboot with the last set of recorded data intact.
The system has 64GB of on board data storage capacity and a data management system to keep this organised. We also include a data processing package for your PC that will read the data files, allow you to add supporting analytical data and then process this to give a graphical output report. The manuals for the DAS and data analysis software are available on request through our enquiry form.
The gas counters can be used to measure biogas volumes directly in which case the gas bag maintains an equilibrium concentration preventing dissolution of biogas component which may distort the result. Alternatively, the gas counters can be fitted in series with CO2 scrubbers which will remove this component to very low levels, giving direct quantification of methane volumes produced by the test substrate.
Gas Counters – Mini
Free standing gas counters fitted with a Omron™ tally counter are offered in 2 sizes the Mini and the Midi. Both offer a convenient and compact way of measuring low volume gas flows where establishing a kinetic is not required. No power supply is needed as the units are powered by an internal lithium ion cell which gives around 3 years of use before replacement is necessary. The mini has a nominal tipping volume of 6ml and can be used individually or made up into banks of 2, 3 and 4 units using a stainless steel base plate. It includes all of the mechanical design features of the full BMP system gasometer and is ideal for carrying out residual biogas potential (RBP) determinations in conjunction with static reactors.
The midi has a tipping volume of 25ml and, as well as being free standing with its own built in counter, has a data connection outlet and can be interfaced with a number of data logging systems including the CJC labs DAS or Lab Jacks™. The midi is ideally suited for use with the CJC Labs 5 litre semi-continuous lab scale reactors
Semi-Continuous Reactor Systems
We can build lab scale anaerobic digesters suitable for semi continuous feeding in a number of sizes but most commonly at a 2 or 5 litre scale. These are again based on a tried and testing design which has been successfully used in a number of research laboratories. Each reactor is continuously stirred and has a feed port in the lid and a drain valve in the base allowing homogeneous samples or waste digestate to be removed. The systems can be rack mounted or supplied with their own individual stands. The reactors are compatible with the Midi gas counters and coupled to the DAS unit. Further information is available on request but a link to an indicative data sheet for 2 x 5 litre reactors is below.