Why not make biogas from straw! New extrusion process it possible that a good feedstock can be created through the far more rapid development of anaerobic digestion of straw.
Research Sources for the Bioextrusion Process
The Bioextruder can create totally new feedstock options such as straw and desiccated grasses, or increase the biogas yield of traditional substrates such as maize or grass silage.
Depending on the solution required Rika Biogas Technologies can also specify equipment that can increase yields, speed up digestion and remove extraneous materials. These items normally sit in line with the extruder to produce a fully integrated feeding and feedstock processing solution that ultimately reduces your running costs. www.bioextruder.co.uk
Bioextrusion was Originated by LEHMANNThe Process of "Bioextrusion research and development was begun by LEHMANN®"
[Bioextrusion] leads to the formation of new bacteria stains and an improved C/N-ratio, because celluloses and hemicelluloses is decomposed and liberated from the embedding lignin layer. The 5- and 6-times sugar is faster available. Low-molecular and fast transforming substances like alcohol and other compounds develop.
The Fraunhofer institute IKTS in Dresden and LEHMANN Maschinenbau GmbH Jocketa have investigated to to what extent these difficult substrates are suitable for biogas production. via www.lehmann-maschinenbau.de
New insights into the impact of bioextrusion on biomass deconstruction using carbohydrate-binding modules
Lignocellulosic biomass is a sustainable source of renewable substrate to produce low carbon footprint energy and materials. Biomass conversion is usually performed in two steps: a biomass pretreatment for improving cellulose accessibility followed by enzymatic hydrolysis of cellulose. In this study we investigated the efficiency of a bioextrusion pretreatment (extrusion in the presence of cellulase enzyme) for production of reducing sugars from corn crop agricultural residues. Our results demonstrate that bioextrusion increased the reducing sugar conversion yield by at least 94% at high solid/liquid ratio (14%–40%). via www.sciencedirect.com
During the process the substrate is decomposed into its cell structure by a double-screw extruder with pressure with that high temperature and resulting of alternating load and multiple pressure/relaxation cycles in the machine. The biogas yield increases due to a better biochemical-availability and a strong enhanced surface area. The fiber is ideal culture medium of metabolizing bacteria.
This leads to the formation of new bacteria stains and an improved C/N-ratio, because celluloses and hemicelluloses is decomposed and liberated from the embedding lignin layer. The 5- and 6-times sugar is faster available. Low-molecular and fast transforming substances like alcohol and other compounds develop.
The sustainability and efficiency of biogas production is primarily determined by the substrate costs. It is necessary to exploit new substrates and to increase the energetic utilization ratio of the used substrates. Till now, highly lignocellulosic substrates or residues like straw or landscaping residue materials as "not or limited usable for biogas production".
The raw fibre is also degradable by bioextrusion. via www.energy-xprt.com
The transcription text of the video: "Let's Make Biogas from Straw" follows:
Let's Make Biogas from Straw Not Field Crops.
Around 30 million tonnes of cereal straw are produced in Germany annually.
It has been estimated that 8 to 13 million tonnes of this could be used sustainably for different energetic paths of utilization.
Large quantities of straw are also produced in the UK, and throughout temperate climate regions globally.
Straw is one of the agricultural residues with the largest untapped potential for use as a biomass feed for biogas.
But, so far here has been only limited use of the energy in straw and what has been used has been based on thermal recovery, such as by pelletizing straw for domestic heating.
The disadvantages of this are the extremely large storage capacity needed for the dry material, as well as the high CO2 emissions from transport and processing.
In contrast, the use of straw in anaerobic digestion seems sensible.
The nutrients and organic matter, which was not converted into biogas in the fermentation process, are available again as a high quality digestate after fermentation, with the resulting digestate available to sustain this as a cycle by, its use as a crop fertilizer.
But there is a problem with this. Straw has a very high content of lignocelluloses and a low portion of readily fermentable materials.
During the fermentation process this causes very long digestion times and a low biogas yield.
Also, straw tends to float in the digester, even after being shredded.
Unwanted floating layers can then easily become a mixing problem, again reducing biogas production.
While some digester mixers might be able to cope, the mixing energy used reduces the remaining energy which can be sold.
A Solution to Low Straw Biogas Yields
One German company has devised a solution which they call Bioextrusion®.
The treatment (extrusion) of the straw has 3 beneficial effects:
1 - It reduces the particle size (fibre length) for reduced viscosity and easier mixing.
2 - The lignocellulosic structure is partially destroyed and,
3 - At the same time, the absorptive capacity of the straw increases, and the floating behavior of straw fibers inside the fermenter is much reduced.
After Bioextrusion® the straw is described as spreading almost perfectly in the operating volume of the fermenter.
Straw substrate which is modified by Bioextrusion® is then suitable for wet-fermentation in the standard CSTR process.
On arable farms Bioextrusion® may also be used to raise biogas output from other crop residues such as maize.
Want to know more?
Phone: +44 (0)1746 714 704
Ultrasound Disintegration Meaning
Ultrasound Disintegration means the breakdown of biogenic sludge into minute particles by external forces.
The resulting increase in surface area causes an acceleration of the organic breakdown process, and thereby results in an increased biogas yield.
For the full article we wrote on this subject visit: https://anaerobic-digestion.com/how-ultrasonic-disintegration-of-sewage-sludge/
In addition, the release of exo-enzymes from the external cell layer increases the enzyme activity in the digester.
In ultrasonic disintegration, the electrical oscillations created by a generator are transformed by a converter (sonic transducer) into mechanical vibrations.
These vibrations are transferred into the surrounding medium by means of a device known as a sonotrode.
Following the rhythm of the ultrasonic frequency, they cause high alternating positive and negative pressure phases, depending on whether the oscillator is expanding or contracting at the time.
During the negative pressure phase, microscopical cavities are formed in the liquid exposed to the ultrasonics; these then collapse in the subsequent positive pressure phase. This process is known as cavitation.
From the implosion, which releases high pressures and temperatures, strong impact and shear forces occur in the area immediately around the cavities, and these cause the surrounding micro-organisms to disintegrate.
Text Source: MCC Process Technology
For more information visit www.mccprotec.com
Watch this video on YouTube here: https://youtu.be/E1z_4_aW9Rc
Wet Process Biodigesters Explained with Pros and Cons
We went back to basics to explain how biodigesters work and their benefits and problems in this video and in the article below. We hope you find it a useful combination of video presentation and reading material.
Biodigesters use the decomposition of organic matter in anaerobic conditions to facilitate the extraction of the resulting biogas for use as energy.
The biodigester has an entrance for the organic material, a space for its decomposition, an outlet with control valve for the gas (biogas), and an outlet for the material already processed (digestate).
Necessary conditions for biodigestion
Temperature is very important for the production of biogas, since the microorganisms that carry out biodigestion reduce their activity outside these temperatures.
The temperature in the digestive chamber must be between 20º C and 60º C. To optimize the production time it is desirable to maintain a temperature between 30º C and 35º C.
The level of acidity determines how the fermentation of the organic material unfolds.
The pH of the material must have a value between 6.5 and 7.5.
Being outside this neutral range, organic matter runs the risk of rotting, as the relative activity of the wrong microorganisms increases. This usually produces a very unpleasant odor.
The container must be perfectly sealed to prevent oxygen from entering and thus have an adequate airtight seal.
The most commonly used materials to produce biogas are manure, from cows, horses, pigs and human sources.
However, almost all organic materials can also be used.
To achieve efficient decomposition, the organic matter must be in digestible sizes, because as ageneral rule, the faster the production of biogas the smaller the particle size.
The organic matter fed into the biogas plant must at all times have a balance of carbon and nitrogen.
Structure of a biodigester
There are many variations in the design of the biodigester.
Some elements that are commonly incorporated are:
Fermentation Chamber: The space where biomass is stored during the decomposition process.
Gas storage chamber: The space where the biogas accumulates before being extracted.
Loading point for adjusting the particle size and a funnel for adjustment of the water content: This is the entrance where the biomass is added to the digester tank (biodigester).
Pile of discharge: The output, serves to remove waste that are spent and are no longer useful for biogas, but can be used as fertilizer (digestate).
Agitator: Displace the residues that are in the bottom up of the biodigester to take advantage of all the biomass.
Gas pipe: The output of biogas. It can be connected directly to a stove or it can be transported by means of the same pipe to its place of use.
Advantages of Biodigesters
The anaerobic digestion process or fermentation process which takes place in all biodigesters, is a renewable and sustainable energy source. Taking advantage of the natural production of biogas reduces the need to use non-renewable energy. This in turn helps reduce climate change, by minimizing the output of greenhouse gases.
It is possible to use secondary products as fertilizer or fertilizer. It avoids the use of local firewood, thus reducing the pressure on forest resources. Encourages sustainable development. Redirect and take advantage of the greenhouse gases produced by landfills and industrial farms, which reduces the carbon footprint of these establishments and decreases their contribution to climate change.
It can help governments comply with national and international responsibilities to reduce the emission of carbon into earth's atmosphere.
It prevents the contamination of aquifers.
Creates specialized jobs.
Creates the possibility of farmers and many other businesses that end-up creating a lot of organic waste matter (biomass) developing a cutting-edge and sustainable "green" project.
Disadvantages, risks and special considerations
Ideally, the location should be close to where the biomass is collected.
The temperature of the digestion chamber must be maintained between 20º C and 60º C; Creating such temperatures may limit its use in cold places.
Biogas contains a byproduct called hydrogen sulfate, which is a corrosive and toxic gas for humans.
As with any other combustible gas, there is a risk of explosion or fire due to malfunction, maintenance or safety.
Biogas contains varying amounts of a byproduct called hydrogen sulfide, which is a corrosive and toxic gas at even very low concentrations for humans.
As with any other combustible gas, there is a risk of explosion or fire due to malfunction, maintenance or safety.
Other names for a biodigester are: Anaerobic digester, anaerobic reactor, biological reactor.
Juan Gonzalo Angel Restrepo www.tvagro.tv
Creative Commons video footage used.