Analysis of Pretreated Biomass
BackgroundLignocellulosic biomass can be highly recalcitrant to conversion to advanced biofuels. It is therefore very important that pretreatments are carried out prior to the main conversion process.
Types of pretreatment include: particle size reduction; steam explosion; ammonia fibre explosion; liquid hot water treatment; dilute acids; alkalis; wet oxidation; organosolv; formic acid; hydrogen peroxide; supercritical CO2; ionic liquids; ozonolysis; and biological pretreatments.
Our Recommendations for Evaluating Pre-Treatment Processes
We have a lot of experience in analysing many products (both liquid and solid) from biomass pre-treatment processes. These samples have covered a wide variety of starting feedstocks and pre-treatment processes and conditions. Below we recommend a set of Celignis analysis packages for getting the most detailed data about the whole conversion process:
(1) The Starting Feedstock
We recommend that analysis package P10 - Sugars, Lignin, Extractives, and Ash is used as this will fully remove the extractives prior to the hydrolysis stage meaning that you can be confident that the sugars reported in this package come from lignocellulose.
We would also recommend analysis package P12 - Sugars in Solvent Extract as this will report the amount of water-soluble carbohydrates in the sample. It is likely that water-soluble carbohydrates will be present in the liquid output of many pre-treatment processes and, if their concentrations are not known, it may be incorrectly inferred that such sugars present in the liquid must come from lignocellulose. However, if the water-soluble carbohydrate composition is known then these values can be substracted from the amounts of sugars in the pre-treatment liquid to determine the amount of true lignocellulosic sugars that are present.
Similarly, if you expect that there will be some starch in your sample then we also recommend that analysis package P14 - Starch Content is also undertaken as starch may also be removed and hydrolysed in many pre-treatment processes.
Additionally, if you are interested in the uronic acid composition of the biomass then we recommend analysis package P15 - Uronic Acids is also undertaken.
(2) The Liquid Product from Pre-treatment
For the most detailed results, we would recommend that the liquid output is analysed using analysis packages P13 - Sugars and Oligosaccharides in Solution, P22 - Organic Acids and Furans, and P15 - Uronic Acids. However, if uronic acids are expected to be very low in your original biomass sample then that analysis package may not need to be undertaken.
(3) The Solid Residue from Pre-treatment
As it is likely that most of the extractives will have been removed in the pre-treatment, it may not be necessary to remove or characterise these. Instead, we recommend that analysis package P9 - Lignocelullosic Sugars and Lignin is undertaken to determine the lignocellulosic composition of the residue. We would also recommend that analysis package P3 - Ash Content is also undertaken to see whether the pre-treatment process significantly changes the ash content of the sample. Also, if the fate of the uronic acids is of interest then analysis package P15 - Uronic Acids could be undertaken.
Analysis of Pretreated Biomass at Celignis
Celignis Analytical can determine the following properties of Pretreated Biomass samples:
Sugar Alcohols and Uronic Acids
Lignin and Extractives
- Ash (Acid Insoluble)
- Volatile Matter
- Fixed Carbon
- Gross Calorific Value
- Net Calorific Value
- Ash Shrinkage Starting Temperature (Oxidising)
- Ash Deformation Temperature (Oxidising)
- Ash Hemisphere Temperature (Oxidising)
- Ash Flow Temperature (Oxidising)
- Ash Shrinkage Starting Temperature (Reducing)
- Ash Deformation Temperature (Reducing)
- Ash Hemisphere Temperature (Reducing)
- Ash Flow Temperature (Reducing)
Major and Minor Elements
Cellulose Content of Pretreated BiomassPre-treatment can greatly change the composition of biomass, with the effect dependent on the process used. For example, dilute acid hydrolysis pre-treatments will hydrolyse a large portion of the hemicellulose fraction, leading to an increased relative cellulose and lignin content in the residual solid biomass.
Click here to see the Celignis Analysis Packages that determine cellulose content.
Hemicellulose Content of Pretreated BiomassMany pre-treatments can result in the hydrolysis of part or all of the hemicellulose fraction, meaning that the concentration of hemicellulose in the residual solid biomass can be decreased.
Click here to see the Celignis Analysis Packages that determine hemicellulose content.
Lignin Content of Pretreated BiomassLignin is a major contributor to the recalcitrance of lignocellulosic biomass to enzymatic hydrolysis. Some organosolv pre-treatments target the removal of the lignin fraction, leaving a relativelty pure cellulose fraction that is more amenable to hydrolysis by enzymes.
Click here to see the Celignis Analysis Packages that determine lignin content.
Starch Content of Pretreated BiomassDifferent pre-treatment processes can have differing effects on the starch contained within biomass. For example, a dilute acid process is likely to remove starch, along with some hemicellulose sugars.
Click here to see the Celignis Analysis Packages that determine starch content.
Uronic Acid Content of Pretreated BiomassDepending on the severity of the pre-treatment conditions, the uronic acids that were present in the original biomass may either have been removed (e.g. hydrolysed) or retained within the residual solid biomass. We can determine uronic acid contents of liquid output streams from pre-treatment processes as well as the uronic acid content of biomass and solid process residues.
Click here to read more about uronic acids and to see the Celignis Analysis Packages that determine uronic acid content.
Ash Content of Pretreated BiomassThe effect of pre-treatment on the ash content and composition will be dependent on the process used.
Click here to see the Celignis Analysis Packages that determine ash content.
Heating (Calorific) Value of Pretreated BiomassThe effect of the pre-treatment process on the heating value of biomass will depend on what biomass components (e.g. extractives, cellulose, hemicellulose, lignin, ash) are reduced and which ones are proportionately increased as a result of the process.
Click here to see the Celignis Analysis Packages that determine heating value.
Biochemical Methane Potential (BMP) of Pretreated BiomassPre-treatment can be a very effective technique to reduce the recalcitrance of lignocellulosic biomass to degradation in anaerobic digestion processes. There have been a large number of studies covering a wide variety of pre-treatments and feedstocks. Many of these have shown a significant increase in the biochemical methane potential (BMP) associated with the pre-treatment.
However, the increase in BMP often varies greatly according to the conditions and type of pre-treatment employed. For that reason we recommend that the biochemical methane potential test is undertaken in order to evaluate the effectiveness of any given pre-treatment process regarding improving potential biogas yields in anaerobic digestion.
Click here to see the Celignis Analysis Packages that determine the biochemical methane potential (BMP) and here to read more about anaerobic digestion and the most important analytes for this process.
Bulk Density of Pretreated BiomassAt Celignis we can determine the bulk density of biomass samples, including Pretreated Biomass, according to ISO standard 17828 (2015). This method requires the biomass to be in an appropriate form (chips or powder) for density determination.
Click here to see the Celignis Analysis Packages that determine bulk density.
Basic Density of Pretreated BiomassAt Celignis we can determine the basic density of some suitable biomass samples. The method requires the biomass to be in an appropriate form (chips) for density determination.
Click here to see the Celignis Analysis Packages that determine basic density.
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