The goal of this glossary is to provide a “primer” for researchers that come from multiple technical disciplines and professional experiences to enable more effective communication and to facilitate R&D activities. This document expands upon the established, general glossary of terms used in the U.S. DOE EERE Bioenergy Technologies Program to include terms specific to R&D activities.
List of Contributors
- Allison Ray (INL)
- Robert Kinoshita (INL)
- Kastli Schaller (INL)
- Magdalena Ramirez-Corredores (INL)
- Devin Lively (INL)
- Bryon Donohoe (NLR)
- Rachel Emerson (INL)
- Ed Wolfrum (NLR)
- Luke Williams (INL)
- Vicki Thompson (INL)
- Troy Semelsberger (LANL)
- Jim Collett (PNNL)
- Jeff Lacey (INL)
- Jordan Klinger (INL)
General Terms & Vocabulary
A
Loss of material due to hard particles or hard protuberances that are forced against and move along a solid surface. (Standard Terminology Relating to Wear and Erosion, Annual Book of Standards, Vol 03.02, ASTM, 1987, p 243-250)
An acid with the structure of C2H4O2.[a] Acetyl groups are bound through an ester linkage to hemicellulose chains—especially xylans—in wood and other plants. The natural moisture present in plants hydrolyzes the acetyl groups to acetic acid, particularly at elevated temperatures.
The process by which a material is soaked, saturated, drenched, seeped, or otherwise permeated with a liquid, in this case an acid. In the realm of polymer chemistry, impregnation denotes the penetration of monomeric, oligomeric, or polymeric liquids into an assembly of fibers.
A system that uses knowledge of the incoming material properties to make adjustments to the process conditions to achieve a consistent result.
Inter-particle cohesion; the sticking of particles to one another or solid surfaces. Agglomeration may occur in response to changing process variables, such as moisture or temperature.
Agricultural crop residues are the plant parts, primarily stalks and leaves, not removed from the fields with the primary food or fiber product.[a] Examples include corn stover (stalks, leaves, husks, and cobs), wheat straw, and rice straw.
A preprocessing operation that separates particles based on size, shape, and density by putting the material in a rising column of air. Finer, lighter particles rise to the top in this process because their sedimentation velocities are lower than the velocity of the gas stream, while the heavier particles fall through the air stream.
A compartment with controlled pressure and parallel sets of doors, to permit movement between areas at different pressures. Failures are the result of overcurrent, thermal capacity overload, blockage, equipment damage (damaged blade), and wear damage (replace damaged flex tips on the blades). These failures can occur as a result of a sudden surge of material, or a longer term buildup of material that leads to excessive current resulting in thermal capacity overload.
A collection of data that is used to support research and decision making.
Shear stress applied to a fluid divided by the shear rate; for non-Newtonian fluids, apparent viscosity is dependent upon shear rate (units, Pa-s).
Inorganic impurities consisting of silica, iron, alumina, calcium, magnesium, sodium, potassium and other noncombustible matter that are contained in the organic resource. Ash increases the weight of the material, and typically adds undesirable costs of handling and processing. Ash content is measured as a weight percent of the material on its dry-basis (moisture-free).
A measurement of the amount of non-combustible inorganic material contained in a sample of biomass (ASTM E1755-01(2015), TP-510-42622).
The process by which inorganics contained in a biomass/feedstock sample are analyzed and subsequently categorized/identified. Ash speciation denotes the elemental composition of the ash and often measures components like, Al, Ca, Fe, Mg, Mn, P, K, Si, Na, S, and Ti (ASTM D3174-12, ASTM D3682-13, ASTM D6349-13, NREL/TP-510-42622).
The lowest temperature at which a material spontaneously ignites in normal atmosphere without an external ignition source, spark, or flame (ASTM E 1491, 2021).
In general, defined as the ability of an item to perform its required function at a stated instant of a time or over a stated period of time.[c] Plant (e.g. biorefinery) availability can be divided into several subtypes: operational, achievable and inherent. For a plant, operational availability reflects system availability including unplanned and planned maintenance time and time lost to operational logistics and administration. An achievable availability reflects availability, including unplanned and planned maintenance time. Inherent availability of a plant measures the availability to be expected when only taking into account unscheduled (corrective) maintenance. Operational availability, although the most realistic of the three, is less important in design evaluations as administrative and logistics downtime is outside the control of the designer. Plant availability is a function of the reliability and maintainability characteristics of a plant.
B
Vermeer BG-480 (Pella, IA) is the grinder responsible for the first-stage of physical deconstruction of corn stover bales into a flowable stream at the Biomass Feedstock National User Facility (BFNUF) process development unit (PDU). The Vermeer BG-480 has two horizontal grinding drums with swinging hammers powered by two, 200-HP, variable frequency drive (VFD) motors and was used to process corn stover bales to pass a 3-inch screen for the FCIC baseline runs.
A bulk measurement performed on bales to obtain a value, qualitatively or quantitatively, related to mechanical fiber strength.
The outer protective layer of a tree, including the inner bark and the outer bark.[a] The inner bark is a layer of living bark that separates the outer bark from the cambium. In a living tree, inner bark is generally soft and moist while the outer bark is a layer of dead bark that forms the exterior surface of the tree stem. The outer bark is frequently dry and corky.
The FCIC system baselines are comprised of the system-wide modeled throughputs, annual capacities, annual biofuel yields and MFSPs, as system-wide functions of the feedstock attributes and impacts that are measured and understood from FY18 Experimental Baseline Runs at the conclusion of FY18 Q3. The baselines are for the systems comprised of (1) conventional corn stover supply and preprocessing/low-temperature (biochemical) conversion to ethanol (2011 Biochemical corn stover to ethanol design case); and (2) conventional loblolly pine residue supply and preprocessing/high-temperature (thermochemical) conversion to mixed hydrocarbons (2013 Pyrolysis and upgrading to hydrocarbons design case).
The Bioenergy Feedstock Library is a Laboratory Information Management System (LIMS) focused on storage and hierarchy-based tracking for physical samples and all associated metadata, including physical, chemical and conversion performance characteristics, for biomass feedstock.[i] In the BFL, samples are assigned an alphanumeric 32-character GUID for data tracking and archive. The library provides tools to store, manage, track, retrieve, and analyze data to help researchers and industry overcome challenges posed by biomass variability.
A biomass-based feedstock that serves as a petroleum replacement in downstream refining, (i.e., sugars, intermediate chemical building blocks, bio-oils, and gaseous mixtures).[a] Algal biofuel intermediates include extracted lipids, lipid-extracted biomass, or bio-oil resulting from hydrothermal liquefaction.
An energy resource derived from organic matter. These include wood, agricultural waste, and other living-cell material that can be burned to produce heat energy.[a] They also include algae, sewage, and other organic substances that may be used to make energy through chemical processes.
Organic material of biological origin constituting a renewable energy source. Usually differentiated into two broad categories: herbaceous biomass (plants with a non woody stem that usually dies at the end of a season), and woody biomass (plants that form a new layer of woody tissue every year, increasing the diameter of the stem). Also defined as the raw, field-run material obtained at the site of production (e.g., field, forest, pond, or landfill). Examples of biomass include corn stover, forest residues, switchgrass, Miscanthus, energy cane, sweet sorghum, high biomass sorghum, hybrid poplars, shrub willows, the non-recyclable organic portion of sorted municipal solid waste, biosolids and sludges, manure slurries, and whole algae.
A national user facility that offers technology and expertise to help the U.S. bioenergy industry overcome challenges during scale up and integration of biomass preprocessing. BFNUF specializes in lignocellulosic feedstock supply and logistics, preprocessing, and analytical characterization. BFNUF capabilities are represented by a full-scale, fully integrated Process Development Unit (PDU) for biomass preprocessing, the Bioenergy Feedstock Library (BFL), and Biomass Characterization Laboratory, housed at INL (https://inl.gov/bfnuf/).
Bio-oil is the liquid produced during pyrolysis (pyrolysis oil). Bio-oil is comprised of hundreds of compounds and standard characterization techniques, while still under development, typically include measurements of water content, elemental composition, and total acid number.
Characterization of bio-oil in terms of chemical components such as carbonyls, acid number, hydroxyl groups, and semi-volatile oxygenated compounds (ASTM D7579-09(2013), NREL/TP-5100-65888, NREL/TP-5100-65890, NREL/TP-5100-65887, NREL/TP-5100-65889).
A facility that processes and converts biomass into value-added products.[a] These products can range from biomaterials to fuels such as ethanol or important feedstocks for the production of chemicals and other materials. Biorefineries can be based on a number of processing platforms using mechanical, thermal, chemical, and biochemical processes.
For a processing plant and project management, it is any obstruction that slows down the flow or the process.[c] It refers to a phenomenon where the performance or capacity of an entire system is limited by a single or small number of components or resources. For a plant with integrated process, the bottleneck is one process reducing the capacity of the whole chain. Bottlenecks create accumulation and down-times affecting throughput and full capacity.
Refers to a thin film of water that is tightly bound to surfaces and unavailable to support microbial activity, whereas free (unbound) water primarily fills void spaces within a solid matrix and is available for reaction. Bound water in a solid exerts an equilibrium vapor pressure less than that of liquid water at a given temperature.
A property defined as the mass of a material divided by the total volume that material occupies. Bulk density is not an intrinsic property, as it can change relative to how material is handled and increases with compaction or depth. Typical units are g/cm3 or kg/m3.
C
A substance that increases the rate of a chemical reaction without being consumed or produced by the reaction.[a] Enzymes are catalysts for many biochemical reactions.
A metallurgical surface modification technique that diffuses carbon and nitrogen into the surface of a metal. It is used to increase the surface hardness of a metal, thereby reducing wear.
Process by which the enzyme cellulase, which converts cellulose into glucose or a disaccharide, adsorbs in an extremely thin layer of molecules (as of gases, solutes, or liquids) to the surfaces of solids (e.g., biomass particles) or liquids that it comes into contact with.
Cellulose is an organic polysaccharide compound with the formula (C6H10O5)n, consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is the most abundant natural form of C on earth. It is crystalline, strong, and resistant to hydrolysis.
A structural layer surrounding some types of cells including all plant and algal cells. Plant cell walls are best envisioned as a fiber reinforced matrix material of intermingled carbohydrate and sometimes lignin polymers. The cell wall is produced in layers or lamella by the living plant.
The remains of solid biomass that have been incompletely combusted;[a] solid product collected after pyrolysis experiments (ASTM D1762-84 (2013)).
Analysis activities to determine the physical and chemical nature of a material. Characterization provides the necessary technical information to develop, screen, analyze, and select appropriate techniques, methodologies and/or process technologies for the use, application, valorization and/or processing of such materials.
A process of removing a substance from a solid material that is dissolved in a liquid, commonly known as extraction in chemical disciplines.
Any quality that can be established by changing the chemical identity of a substance. A property of a material that becomes evident due to or as a result of a chemical reaction.
A control system that uses knowledge of process conditions to automatically adjust control elements in response to disturbances.
Action or property of like molecules sticking together, being mutually attractive. It is an intrinsic property of a substance that is caused by the shape and structure of its molecules.
The action of reducing solid materials by crushing, grinding, or cutting, to smaller particles or fragments.
A prepared feedstock product that has constant characteristics throughout both an individual sample taken at random as well as the entirety of a shipment. In other terms, a feedstock product that has all characteristics fully understood and maintained at a specified level with minimal to no variation.
National Instruments modular I/O system for interfacing LabVIEW to field sensors, devices and actuators.
A measure of feedstock reactivity, under desired process conditions to yield product of interest. It is an inherent ability of a given feedstock (or feedstock component) to render (be converted to) the desired product.
A measure of feedstock reactivity, under desired process conditions to yield product of interest. It is an inherent ability of a given feedstock (or feedstock component) to render (be converted to) the desired product.
Failure of the conveyer system due to a sudden surge of biomass, or a long term buildup of biomass, resulting in overcurrent, thermal capacity overload, blockage, equipment damage (bent flight, torn belt, locked up bearing), and wear damage. These failures can limit the operational reliability of an integrated biorefinery.
A separation device that removes particulates from an air, gas or liquid stream, without the use of filters, through vortex separation.
D
Sample tracking. A sample is defined as any quantity of biomass or intermediate that has been tagged under the FCIC project and is currently being tracked in a database. In FCIC, the data management approach is accomplished through the integration of the Bioenergy Feedstock Library and LabKey to coordinate and facilitate sample tracking, archive and annotation of metadata, and data exchange among the eight National Laboratories of the FCIC.
Data mining is the process of extracting potentially useful information from data sets.[f] It uses a suite of methods to organize, examine and combine large data sets, including machine learning, visualization methods and statistical analyses. Data mining enables the examination of large databases in order to discover and extract patterns that generate new information and understanding. Data mining is used in computational biology and bioinformatics to detect trends or patterns without knowledge of the meaning of the data.
Solubilization and removal of acetyl groups from biomass structures using an alkali de-esterification step. Deacetylation is conducted at mild temperatures (<100°C) and low alkali loadings (ranging from 40-100 kg NaOH per ODMT (oven dried metric ton) at atmospheric pressure.
Deacetylation followed by mechanical refining in a disc refiner.[j] Disc refining is a system for refining paper pulp to achieve the desired structural and binding characteristics to cellulose fibers.
The removal of mineral contaminants (ash and soil).
The ability or ease with which a material or substance goes from a region of high concentration to a region of low concentration as a result of random motion.
A thermochemical pretreatment for lignocellulosic biomass employed in biochemical conversion pathways that is used to produce materials with acceptable enzymatic digestibilities.[h] Dilute sulfuric acid pretreatment at temperatures ranging 140° to 200°C renders the cellulose in cell walls more accessible to saccharifying enzymes. The hemicelluloses are hydrolyzed and the sugars are solubilized as monomers and oligomers, depending on severity; however, the yields of solubilized sugars are less than quantitative (i.e., 60 to 70%). Dilute-acid pretreatment conditions used in the FCIC FY18 Experimental baselines were were 160°C, 10 minutes nominal residence time, and 19 mg sulfuric acid/g biomass effective acid loading in the reactor. The solids content of the feedstock entering the reactor was ~60wt.% for each of the runs; following steam addition and flashing, the pretreatment slurry was between 30-40 wt. % total solids.
A disc refiner consists of two vertical disks with grooved, serrated or contoured surfaces.[j] Opposing discs rotate counter to one another—one disc rotates clockwise, while the other either remains stationary or rotates counterclockwise. A slurry is pumped between the discs, and the cell walls of the fiber are defibrillated and delaminated, as centrifugal force pushes the fibers out toward the perimeter of the disks. The distance of the gap between the discs can be adjusted, depending on the extent of refining required for end-use.
A numerical technique that models the iteration between individual particles and boundaries to predict bulk solids behavior. This tool can easily model moving boundaries and is used to gain better understanding of particle flow dynamics. The knowledge is then applied to design more efficient equipment, thus improving process efficiency and product quality.
The process of codifying the behavior of a complex system as an ordered sequence of well-defined events. In this context, an event comprises a specific change in the system’s state at a specific point in time. A stochastic modeling tool, similar to Monte Carlo simulation.
A machine used to transfer solid granular materials across a horizontal distance or up an incline using a multitude of ‘bars’ attached at both ends to chains, which are pulled through the length of the machine by sprockets connected to an electric motor.
A measurement of the mass of biomass or material that remains when water is removed.
A device used to separate fine solids entrained in a stream of air. May be assisted by a cyclone separator.
E
A measure of elastic deformation of a body under stress, which is recovered when the stress is released.[l] Ratio of stress to strain in the elastic region of a material is the modulus of elasticity (see Young’s modulus).
Measures a material’s resistance to elastic deformation (non-permanent deformation) when stress is applied.[m] The elastic modulus is defined as the slope of a material’s stress-strain curve in the linear, elastic regime.
The ability of a material to recover after experiencing stress and subsequent removal of that stress, also referred to as springback.[l] When the applied stress exceeds the elastic limit, the material will no longer recover to its original dimension.
Determines propensity of a dust/powder to accumulate charge under flow conditions.
The distribution of elements in the biomass expressed as C, H, O, N, and S as measured by ultimate analysis. Another common compositional measurement technique for high temperature pathways is proximate analysis, which measures volatile matter, fixed carbon, and ash.
A commodity (crop) grown specifically for its fuel value,[a] including food crops such as corn and sugarcane and nonfood crops such as poplar trees and switchgrass.
Amount of energy contained per unit volume.
The quality of energy is defined as the relative amount of mechanical work that can be generated in a theoretical conversion process. The contrast between different forms of energy that may refer to different trophic levels in ecological systems or the propensity of energy to be transformed from one form to another.
ASTM E 1226; provides a relative measure of the explosion magnitude with respect to pressure output and rate of pressure rise as a function of powder concentration.
Defined by Eckhoff as “an exothermic chemical process that, when occurring at constant volume, gives rise to a sudden and significant pressure rise.” Dust explosions are of particular concern in mechanical processing industries that include agricultural practices involving the storage and handling of grain and feed.[b]
The part of biomass that can be extracted by water or ethanol or other solvents. Extractives include non-structural components of biomass samples that are not integral to the cellular structure. Water soluble materials may include inorganic material, non-structural sugars, and nitrogenous material, as well as inorganic salts and compounds associated with either the biomass itself, soil or fertilizer. Ethanol soluble material may include chlorophyll, waxes, or other minor organic components.
F
Pyrolysis in which reaction times are short, resulting in higher yields of certain fuel products ranging from primary oils to olefins and aromatics depending on the severity of conditions.[a] Fast pyrolysis is a high temperature (400-500 °C) process in which biomass is rapidly heated (a few seconds) in the absence of oxygen. Pyrolysis is the thermal decomposition of organic substances, like lignocellulosic biomass, in the absence of oxygen to form liquids, solids (biochar), and non-condensable gases; the rate of pyrolysis has a profound impact on product distributions. In fast pyrolysis, the goal is to produce energy rich bio-oils as the primary product. Pyrolysis yield is defined as the carbon efficiency of conversion of biomass to bio-oil.[n] In general, ‘fast pyrolysis’ colloquially refers to a subset of pyrolysis conditions where the process is limited by reaction kinetics compared to heat or mass transport phenomena, and is often targeted due to relatively higher liquid product yield.
A feature is an individual measurable property or characteristic of a phenomenon being observed in machine learning and pattern recognition. An attribute or group of attributes that constitute a characteristic property or set of properties which is unique, measurable and differentiable.
A closed loop control system that uses an error signal derived from the measurement of a current process condition, compared to a set point, or desired process condition, in order to generate a control output to adjust to process disturbances.
Feedforward control describes measuring process disturbances and adjusting the control signal as a function of the disturbance to obtain a direct and momentary compensation of the disturbance. Feedforward is a term describing an element or pathway within a control system that passes a controlling signal from a source in its external environment to a load elsewhere in its external environment.
The main raw material used in a processing unit or industrial process to be converted into a product or products. BETO’s MYPP (2016) defines feedstock as biomass materials that have undergone one or more preprocessing operations (e.g., drying, grinding, milling or chopping, size fractionation, de-ashing, blending and formulation, densification, and/or extraction) to ensure that the physical and chemical quality characteristics are acceptable for feeding into a biorefinery process that can efficiently convert the feedstock at high yield into biofuels, biopower, and/or bioproducts. Any material used directly as a fuel, or converted to another form of fuel or energy product. Bioenergy feedstocks are the original sources of biomass.[a] Examples of bioenergy feedstocks include corn, crop residue, and woody plants.
The Feedstock-Conversion Interface Consortium (FCIC) is an integrated and collaborative network of eight national laboratories (ANL, INL, LBNL, LANL, NREL, ORNL, PNNL, SNL) dedicated to addressing technical risks and understanding how biomass properties influence collection, storage, handling, preprocessing and conversion technologies with the goal of improving the overall operational reliability of integrated pioneer biorefineries (https://www.energy.gov/eere/bioenergy/feedstock-conversion-interface-consortium).
The FCIC system baselines are comprised of the system-wide modeled throughputs, annual capacities, annual biofuel yields and MFSPs, as system-wide functions of the feedstock attributes and impacts that are measured and understood from FY18 Experimental Baseline Runs at the conclusion of FY18 Q3. The baselines are for the systems comprised of (1) conventional corn stover supply and preprocessing/low temperature (biochemical) conversion to ethanol (2011 Biochemical corn stover to ethanol design case); and (2) conventional pine residue supply and preprocessing/high temperature (thermochemical) conversion to mixed hydrocarbons (2013 Pyrolysis and upgrading to hydrocarbons design case).
The process or theory by which a system is designed to move biomass from its point of creation (e.g. where it was farmed) to its point of conversion (e.g. the throat of the reactor) at a predetermined cost target.
The features and characteristics of a feedstock set against defined standards for a given processing unit that makes it suitable to be processed through such unit. Typically, this list of product quality measures (features and characteristics) represents a requirement or mandate if designated by a user and/or a guarantee if designated by a producer.
Stover material that has been collected in a manner that severs the stalk at an operator-determined height (that varies based on soil type, soil management practice, tillage practice and/or operator attention), provides some initial size reduction, and incorporates lower stalk materials into a bale. Lower stalk materials are higher in ash and moisture relative to the upper stalk. Also, the lower stalk may be encrusted with soil as a result of splashing during rainfall in the growing season. Soil contamination is typically uniformly spread throughout the bale and resides on or in stalks, leaves, husks, and cobs. Pacific Ag, Abengoa, and DuPont utilized this type of bale.
Ease with which a material will flow under a given set of conditions; material with high flowability indicates material with ease and consistency of transport, conveyance, and feeding.
A gasifier or combustor design in which feedstock particles are kept in suspension by a bed of solids kept in motion by a rising column of gas.[a] The fluidized bed produces approximately isothermal conditions with high heat transfer between the particles and gases.
Includes tops, limbs, and other woody material not removed in forest harvesting operations in commercial hardwood and softwood stands, as well as woody material resulting from forest management operations such as pre-commercial thinnings and removal of dead and dying trees2. Waste materials that the current forest industry is not using, consisting of tops, branches, needles, and cutoffs. The Loblolly pine residues collected for the FCIC FY18 baseline runs represent mixtures of tops, branches, needles, and bark from trees that are 11-25 years of age.fractional milling
Process by which biomass screening is done in a continuous, seamless fashion in an automated system with subsequent removal of biomass already at target particle size. This is implemented to prevent over processing of material; only biomass that needs to be ground to target size will be part of the grinding process.
Free or unbound water primarily fills void spaces within a solid matrix and is available for reaction; unbound water has an equilibrium vapor pressure equal to that of liquid water at a given temperature. The electrical polarity of water allows it to bond tightly to charged surfaces and to other molecules of water. Bound water refers to a thin film of water that is tightly bound to surfaces and unavailable to support microbial activity.
G
The energy equivalent of a gallon of gasoline.
Compares two things; what is, with, what should be; documents data gaps. The gap analysis for the FCIC consisted of four steps:
- Defining the “Present State” by completely understanding the process/organization which needs improvement.
- Defining the “Future State,” by setting the goal(s) for the future.
- Identifying whether a gap (or gaps) exist between or among the company’s present and future states; if so, the gap description(s) should then outline what constitutes the gap(s), and the factors that contribute to it.
- Developing a Proposal/Solution consisting of a report that lists all the possible solutions that can be implemented to fill the gap between the current and future states. FCIC’s “Present State” consists of well-defined, field-to-biofuel process flows and unit operations for the conventional feedstock supply systems and the two selected design cases. The “Future State” for FY18 is informed modeled Baseline scenarios for the systems comprised of (1) conventional corn stover supply and preprocessing/low temperature (biochemical) conversion to ethanol; and (2) conventional pine residue supply and preprocessing/high temperature (thermochemical) conversion to mixed hydrocarbons.
Universally unique identifier that is used for sample identification and tracking in the Bioenergy Feedstock Library (BFL). In the BFL, samples are assigned an alphanumeric 32-character GUID.
The collective participation of individuals, organizations and stakeholders for the articulation of the different components needed for grades assignment to materials and products. A list of components include: QA/QC testing, equipment/techniques & methods/operating processes, documentation, responsibilities, records, labeling, storage/handling/delivery, inspection and re‐inspection criteria, non‐conformance, training, etc.
Characteristic of a material that describes its ease of comminution.
H
A machine that uses a multitude of swinging hammers or bars of various configurations attached to a rotating shaft, to break down solid materials using kinetic energy and impact.
An increase in the yield stress of a material under uniaxial loading is referred to as hardening. During hardening, the elastic domain is altered due to microstructural changes in the material that occur during plastic flow.
In a defined system, the amount of heat (cal, kcal, J) needed to raise the system’s temperature by one degree (°C or K). Expressed in units of thermal energy per degree temperature (J/K).
It is another polysaccharide accompanying cellulose in lignocellulosic materials. It is a heteropolymer composed by xylan, glucuronoxylan, arabinoxylan, glucomannan, and xyloglucan (including sugar monomers: xylose, mannose, galactose, rhamnose, and arabinose).[f] Hemicellulose has a random, amorphous structure with little strength, easily hydrolyzed by dilute acid or base as well as a myriad of hemicellulase enzymes.
The heat produced by combustion of one unit of substance at constant volume in an oxygen bomb calorimeter under specified conditions.[a] The conditions are: initial oxygen pressure of 2.0–4.0 MPa (20–40 atm), final temperature of 20º–35ºC, products in the form of ash, liquid water, gaseous CO2 and N2, and dilute aqueous HCl and H2SO4. It is assumed that if significant quantities of metallic elements are combusted, they are converted to their oxides. In the case of materials such as coal, wood, or refuse, if small or trace amounts of metallic elements are present, they are unchanged during combustion and are part of the ash. Also known as gross heat of combustion (ASTM D 5865-10a).
ASTM E 2021-06; this test method covers a procedure that determines the minimum temperature at which a dust layer will self-heat using differential scanning calorimetry.
A chemical map of biomass particle surfaces that helps inform their bulk behavior in terms of particle-particle interactions and wettability.
The physical property of a molecule (or substance) that makes it repelled, tend to not combine with, or otherwise incapable of dissolving in water.
I
The rate at which biomass or other material can be considered thoroughly permeated by a liquid.
Constant speed AC electrical motor, induced torque via rotating magnetic field. Can be either 3 phase or single phase.
A system that uses a status signal from downstream equipment to automatically start and stop a piece of equipment, in order to prevent plugging and potential damage to equipment.
J
K
L
A flexible system currently in use at the INL for sample tracking, utilizes unique programming language SQL.
National Instruments engineering software package for test, measurement, data acquisition, and control.
A tool that can be used to evaluate the potential environmental impacts of a product, material, process, or activity. An LCA is a comprehensive method for assessing a range of environmental impacts across the full life cycle of a product system, from materials acquisition to manufacturing, use, and final disposition. In other words, it is a technique to assess environmental impacts associated with all the stages of a product’s life; from raw material extraction through materials processing, manufacture, distribution, use, repair, maintenance, and eventual disposal or recycling.
A structural component of biomass materials made up of complex cross-linked phenolic polymers that provides structural rigidity for cell walls.[a] Lignin typically makes up 10-30% of the biomass material and is more abundant in woody material than herbaceous material. A complex polymer that serves as a component of wood and vascular plants, making them firm and rigid. Produces energy in the form of electricity when burned.
Lignin is made of three primary monolignols: poumaryl alcohol, coniferyl alcohol, and sinapyl alcohol which are incorporated into lignin as p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S). The ratio of these major building blocks and the relative abundance of the linkage types that connect them, changes with biomass type.
These are the building units in lignin.[f] The fundamental compounds namely, p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol are cross-linked as phenylpropanoid units: the H- (p-hydroxyphenyl), G- (guaiacyl), and S-unit (syringyl), respectively.
“Lignocellulose-derived hydrolysates contain several different inhibitors (collectively called lignotoxins or LTs) that arise during pre-treatment of biomass”, e.g., phenolic compounds derived from lignin that are released during thermochemical treatment of lignocellulosic biomass.
(no ASTM standard available yet) Measure of the oxygen concentration below which an explosion will not occur. Used in designing inert systems.
The heat produced by combusting one unit of a substance, at atmospheric pressure, under conditions such that all water in the products remains in the form of vapor.[a] The net heat of combustion is calculated from the gross heat of combustion at 20oC by subtracting 572 cal/g (1,030 Btu/lb) of water derived from one unit mass of sample, including both the water originally present as moisture and that formed by combustion. This subtracted amount is not equal to the latent heat of vaporization of water because the calculation also reduces the data from the gross value at constant volume to the net value at constant pressure
M
A control system that uses knowledge of process conditions to signal a human operator to make changes to the control elements.
A six-carbon sugar. A product of hydrolysis of mannan found in the hemicellulose fraction of biomass.[a] A sugar monomer of the aldohexose series of carbohydrates (C6H12O6). Mannose is a C-2 epimer of glucose.
The percent by weight of the total samples extracted from the biomass sample, compared to the weight of the original sample.[a] It is a sum of the weight percent of moisture, extractives, ash, protein, total lignin, carboxylic acids, and five and six carbon sugar monomers and polymers. This is a good indicator of the accuracy of a complete biomass compositional analysis.
Stover material that has been collected into a loose windrow directly behind the combine during grain harvest. Bales are comprised primarily of only the materials that have passed through the combine during grain collection—upper stalk, leaves, husks, and cobs. These bales are enriched in cobs/depleted in lower stalk relative to flail shred bales, therefore may have a higher xylan content and lower ash and moisture as a result of anatomical fractionation during collection. (Also see EZ-Bale, a POET DSM trademark).
The maximum pressure occurring in a closed vessel during the explosion of an explosible dust atmosphere determined under specific test conditions.[k] The test chamber is only 20 L, which may not allow for full flame development. The level of dust turbulence can also be different in actual process than standard test vessel, so this should also be considered in determination of deflagration index (Kst).
Mechanical refining has been used in the pulp and paper industry to separate chemically pulped fibers after pulping and also to improve papermaking properties. Papermaking properties are improved with mechanical refining by externally fibrillating the exterior wall of the fiber and by delaminating the interior cell wall of the fiber to increase swelling and flexibility. During the refining process, cellulosic fibers are mechanically treated in water, resulting in morphological and structural changes; fibers are fibrillated internally and externally. Fibrillations caused by the high-shearing force of a refiner can significantly increase surface area, facilitating enzyme access to cellulose.
A fast pyrolysis technique that uses microwave radiation as a means to rapidly heat (up to 200 °C/s) samples to target reaction conditions.
Data about data that facilitates organization, tracking, searching, and understanding of data. Metadata provides a description and context for data and facilitates data analysis.
A temporary storage container with leveling screws at the top for distributing incoming materials, a variable speed live floor for moving material to one end where it is discharged onto a conveyor by ‘doffers’, or horizontally oriented rotating shafts that perform ‘rake’ like sluffing of material off of the moving pile in a controlled manner. This is used to provide a surge capability and to provide more constant flow into downstream equipment.
Uses imaging and image analysis to quantify morphological descriptors of biomass particle shape such as aspect ratio, roundness, and circularity. Particle roughness is measured from z-stacks or tilt pairs of images to calculate depth. These qualities are closely related to inter-particle friction and spatially dependent multi-dimensional Young’s moduli.
ASTM E 1515; amount of dust, when dispersed in air, required to propagate a dust explosion. MEC is ignition energy dependent; if the ignition energy is too high, the result may be an unrealistically low MEC, indicating explosibility when the dust is not.
ASTM E 2019; a relative measure of the least amount of spark discharge energy required to initiate a dust explosion.
Any kind of plan put into place to achieve better throughput, lower cost, or to improve the quality and efficiency of integrated biomass preprocessing and conversion.
The quantity of water contained in a material. Wet basis moisture content is defined by the percentage equivalent of the ratio of the weight of the water to the total weight of the material. Dry basis moisture content is defined by the percentage equivalent of the ratio of the weight of the water to the weight of the dry matter (ASABE/ASAE S358.2).
Integrated assembly of power distribution equipment and motor controllers in a modular enclosure system.
May be stand alone or inside an MCC. May be ‘across the line contactor’, ‘soft start’, or variable frequency drive (VFD). Also contains overload.
N
A heat treating process that diffuses nitrogen into the surface of a metal to create a case-hardened surface.
The viscosity of the fluid changes in response to shear rate or depends upon shear rate history. The behavior of the fluid under shear can be described in four general categories. Dilatant means that the viscosity of the fluid increases as shear is applied. Pseudoplastic means that the viscosity of the fluid decreases as shear is applied. Rheopectic is similar to dilatant, however the viscosity increase when shear is applied is time-dependent. Thixotropic is similar to pseudoplastic, however the decrease in viscosity when shear is applied is time-dependent.
O
Vocabularies of representational terms – classes, relations, functions, object constants – with agreed-upon definitions, in the form of human readable text and machine enforceable, declarative constraints on their well-formed use. Ontologies go beyond the level of taxonomy to define logical, syntactic relationships between terms.
A simple control system whereby the control element is manually set to a particular position based on process conditions.
Defined as the probability that the system will achieve a specified annual design capacity, biofuel yield and minimum fuel selling price. This is different from the classical definition of reliability of a piece of equipment (the ability to consistently perform its intended or required function or mission, on demand and without degradation or failure), because it considers the interactions among system components on annual capacity and the operational performance of the aggregate system. In the sense of a biofuel value chain that reaches from field to biofuel product, “degradation” refers to reduced throughput and therefore reduced annual capacity, as well as reduced rates, titers and yields of intermediates and products caused by compositional and moisture variability. “Failure” refers to equipment downtime caused by physical and mechanical properties of the feedstock that are outside the bounds for which the equipment was designed.
Term used to describe conditions and subsequent actions taken for when an operator (human) must step in to fix or amend an automatic system/process.
Protective device for electric motor. Shuts down or ‘trips’ based on percentage of the ‘full load amps’ (FLA) greater than 100% for a length of time. May be thermal or electronic (‘Tesys-T’, Schneider Electric trade name). Tesys-T also adds control and diagnostic capabilities.
P
Any details relating to the size and/or shape of particles (biomass or other) that may have an effect on the way the material behaves in a chemical, processing, or manufacturing environment.
A list of values or a mathematical function that defines the relative amount, typically by mass, of particles present according to size. Care needs to be taken when measuring the PSD to ensure that particles are not agglomerated thereby increasing their apparent average size of the distribution (ASABE/ASAE S424.1).
Describes the mechanical integrity of a material, its ability to withstand external stress, wear, pressure or damage, and is important to comminution.
A physical property is a characteristic of matter that is not associated with a change in its chemical composition. Properties other than mechanical properties that depend on the physics of the material, including density, thermal and electrical conductivity, and thermal expansion.
Deformation that remains after the load causing it is removed.[d] It is the permanent part of the deformation beyond the elastic limit of a material, also called plastic strain and plastic flow.
Ratio of lateral strain to axial strain in an axial loaded specimen.[d] Poisson’s ratio is the constant that relates modulus of rigidity to Young’s modulus in the equation:
E = 2G(r + 1)
where, E is Young’s modulus; G, modulus of rigidity; and r, Poisson’s ratio. The formula is valid only within the elastic limit of a material. A method for determining Poisson’s ratio is given in ASTM E-132.
A general term used to describe the porosity, pore size, pore size distribution, pore volume, and pore morphology (form, shape) of a porous medium.
A measure of the void (i.e. “empty”) spaces in a material, and is a fraction of the volume of voids over the total volume. Increased porosity facilitates enzyme access and liquid permeation.
Any physical or chemical preliminary process applied to raw materials or intermediate streams to render a product or stock with adjusted properties to fulfill the specifications of another process in which that product or stock is meant to be processed. A preprocess/pretreatment is something applied to a raw material or an intermediate stock in order to improve the processing step or stage and/or to make it more effective. Sometimes preprocessing is applied to physical processes in order to limit pretreatment for chemical processes. In this way, preprocessing is seen as a milder manipulation and pretreatment a more severe processing.
Severity is defined as the combined effect of temperature, acidity, and duration of treatment.[h] Hot-water pretreatments, which actually use acetic acid liberated from cell-wall hemicellulose, represent the lowest degree of severity. The severity factor, R0, can be calculated as follows,
R0 = t • exp((T(t) – 100) / 14.75)
where t is the residence time (min) and T is the pretreatment temperature (°C). Combined severity factor (CSF) is an alternative, and more commonly employed approach, to combine lignocellulose pretreatment reaction time, temperature, and the addition of acid or base catalysts into a single factor.
CSF = log(R0) – pH
A thermal process for the cracking, fragmentation, decomposition or deconstructuion of macromolecules or heavy organic molecules. In the case of biomass, it is carried out at high temperatures (greater than 300°C) in the absence of oxygen. The end product of pyrolysis is a mixture of solids (char), liquids (oxygenated oils), and gases (methane, carbon monoxide, and carbon dioxide) at different proportions, determined by operating conditions (temperature, pressure, oxygen content of the feedstock, etc). Pyrolysis is categorized in terms of the heating rate as slow, (rapid) fast or flash, as well as the pressure condition e.g. vacuum pyrolysis.[f] Fast pyrolysis is a high temperature (400-500 °C) process in which biomass is rapidly heated (a few seconds) in the absence of oxygen. In fast pyrolysis, the goal is to produce energy rich bio-oils as the primary product.[n] Pyrolysis yield is defined as the carbon efficiency of conversion of biomass to bio-oil. In general, ‘fast pyrolysis’ colloquially refers to a subset of pyrolysis conditions where the process is limited by reaction kinetics compared to heat or mass transport phenomena, and is often targeted due to relatively higher liquid product yield. The breaking apart of complex molecules by heating in the absence of oxygen, producing solid, liquid, and gaseous fuels.[a]
The solid residue produced and recovered upon extraction of water soluble compounds from pyrolysis oil, i.e. water-insoluble precipitate.
The liquid product resulting from the thermochemical (pyrolysis) conversion of biomass (bio-oil), composed mainly of oxygenated compounds and water.
Q
R
A bale made using a mechanical windrower (bar rake, basket rake, wheel rake, tedder), which may be actuated by ground contact (i.e. a ground driven wheel rake) or powered externally (i.e. a hydraulic basket rake). Raked bales are often soil contaminated as a result of direct contact between the biomass and the equipment and the soil.
“Recalcitrance can be broadly defined as those features of biomass that disproportionately increase energy requirements, increase the cost and complexity of biorefinery operations, and/or reduce the recovery of biomass carbon into desired products.” Recalcitrance is defined by McCann and Carpita as an emergent property of the molecular and structural complexity of a plant cell wall and how that structure interacts with catalysts during pretreatments and conversion. This definition recognizes that the complexity of plant cell walls and particle interactions at the mesoscale (e.g., differing proportions of cell types or anatomical fractions, sizes, shapes, and inter-particle cohesion and adhesion) impart emergent biophysical properties. Himmel et al. defined recalcitrance as the natural resistance of plant cell walls to microbial and enzymatic deconstruction.[h]
By-products from processing all forms of biomass that have significant energy potential.[a] For example, making solid wood products and pulp from logs produces bark, shavings and sawdust, and spent pulping liquors. Because these residues are already collected at the point of processing, they can be convenient and relatively inexpensive sources of biomass for energy.
Rheology testing is measuring the deformation of matter under the influence of imposed stress by analyzing the internal response of materials to forces.[d] Flow characteristics of lignocellulosic biomass and feedstocks are critical to conversion and production processes; when a material is forced to flow, the rheological characteristics determine the processability. Rheological properties are dependent upon shear rate (rate of deformation), temperature, molecular weight and structure, and concentration.
A collective term that describes a wide range of approaches, tools, and techniques used to uncover causes of problems. Examines the highest level of a problem to identify the root cause. A root cause is a factor that caused a nonconformance (or system upset) and should be permanently eliminated or mitigated through process improvement.
A horizontally oriented rotor with a multitude of cavities, rotating at low speed; usually used for transferring solid and granular materials from beneath a hopper and/or across a pressure difference.
A system used to remove moisture from feedstocks by agitating a bed of material in a rotating drum, in the presence of a stream of heated air. The air is heated by a natural gas fired burner, and drawn through the rotary drum and a downstream cyclone separator, by an induced draft fan. The entrained dried solids are separated from the air stream by the cyclone, passed through a rotary airlock, and then conveyed to downstream equipment or storage. The INL dryer drum has an annular three pass configuration, where the material is fed into the center of the drum, and is transferred to the opposite end where is drops into the middle section, then passes back to the feed end and finally to the outer section of the drum and out thought the cyclone.
Round bale with dimensions, 6 ft. diameter by 5 ft. width cylindrical, comprised of a concentrically wrapped windrow made from a 16′ x 1,400′ long strip within a field with a density of 7 to 10 lb. /cu ft. (dry matter basis).
S
Any quantity of biomass that has been prepped, processed, or otherwise handled under the FCIC project.
The history of a given sample in the BFL.
A machine used to transfer solid granular materials across a horizontal distance or up an incline, using a rotating shaft with helical ‘flights’ also simply called the ‘screw’.
Second-stage equipment in BFNUF’s 2-stage grinding operation, used to perform final size reduction of the material flowing from the first stage grinder. The second stage grinder is a 150-hp vertically fed Bliss Eliminator hammer mill.
Process by which particulates settle to the bottom of a liquid and form a sediment over a given period of time. Particles will tend to move in a uniform manner in the direction of a given force, common forces are gravity and centrifugal motion.
In the context of engineering, it is a directional word referring to forces or stresses. A shear force goes parallel to the surface of an object or material. Shear stress can happen between two objects or within the same object. A shear stress between two objects occurs when a force pulls the object along the same plane as the face of the object abutting another object that is being pulled in the opposite direction. A shear stress within an object will occur when a force parallel to the plane causes one plane of the material to want to slip against another, thus deforming the material.
Process by which a powdered material is forced to coalesce into a solid or porous mass by heating it without liquefaction. The heating process is commonly accompanied by compressing of the material.
Term used to denote when a machine, on startup, has an artificially reduced amount of current delivered to it.
Rectangular bale with dimensions, 3x4x8 or 4x4x8 feet, and comprised of 30 to 36 individual “flakes” made from discrete locations approximately 16 ft. x 48 ft. within a field with a density of 8 to 12 lb. /cu ft. (dry matter basis).
The process by which a particle will be subjected to different stress types (grinding, milling, shearing, shredding) at various intensity levels, with the express purpose of observing when and how particles fail.
At the macroscopic level, any physical change of a given material that is observable to the naked eye. At the microscopic level, any change in the conformation or organization of a material’s molecular or chemical structure that changes any of its given properties.
T
An integral tool for both research and commercial project development, TEA combines process modeling and engineering design with economic evaluation to provide cost-benefit comparisons. TEA helps to assess the economic viability of a process and provides direction to research, development, investment, and policy making. Assessments are used for tasks such as evaluating the economic feasibility of a specific project, investigating cash flows over the lifetime of a project, evaluating the likelihood of different technology scales and applications, and comparing the economic quality of different technology applications providing the same service.
A material property that describes a materials ability to conduct heat generally given in W/m*K. Defined as the quantity of heat transmitted through a unit thickness of a material, in a direction normal to a surface of the unit area, due to a unit temperature gradient under steady state conditions.
A material property that describes a material’s ability to lose heat or react to changes in temperature. Calculated as the thermal conductivity divided by density of the material and specific heat capacity at a constant pressure.
Controlled heating or oxidation of feedstocks to produce energy products and/or heat, e.g., pyrolysis, gasification, combustion.
Thermodynamic properties are divided into intensive and extensive properties. An extensive property depends on the size of the system (volume, mass, moles). An intensive property can exist at any point in space (temperature, pressure, density). Specific properties are extensive properties per unit mass; specific properties are intensive because they do not depend on the mass of a system (specific volume, specific heat, specific gravity).
A thermal process to convert biomass into a coal-like material.[e] Torrefaction is a lower-temperature (200–300◦C) pyrolysis of biomass that removes water and volatiles, increasing its energy density and susceptibility to mechanical preprocessing. Torrefied biomass has improved fuel characteristics, like increased energy density, and is more brittle, which facilitates comminution by making the process less energy intensive.
Genetic or physical characteristics of an organism[e] (physical characteristics are also referred to as phenotypes).
A device that uses a planar heat source to measure thermal properties (thermal conductivity and thermal diffusivity), with the potential to incorporate corrections for anisotropic materials such as biomass. Typical devices use concentric rings or square resistive filaments to impart a controlled heat input to the material while the change is resistance at the sensor/sample interface can be fit to heat transport models to yield information about the heat uptake and propagation through a sample. The thermal properties are results of a fitting procedure between measured experimental data and theory.
The study of friction, wear and lubrication, encompassing how interacting surfaces behave in relative motion.
U
Characterization of biomass in terms of its individual constituent elements[e] (C, H, O, N, S, etc., also see elemental composition).
Free or unbound water primarily fills void spaces within a solid matrix and is available for reaction; unbound water has an equilibrium vapor pressure equal to that of liquid water at a given temperature.
A basic step in a process that involves a physical change or chemical transformation.
V
Property that describes a material which is viscous, but also exhibits certain elastic properties, such as the ability to store energy of deformation, and in which the application of a stress gives rise to a strain (or vice versa) that approaches its equilibrium value over a significant time interval.[d] It is not possible to describe viscoelastic materials using either classical fluid mechanics (Newtonian) or classical elastic mechanics (Hookean). The rheology (flow behavior) of viscoelastic materials is related to the structure, molecular weight, and interaction of their molecules.
The chemical composition of species produced during pyrolytic reactions.
The tendency of a substance to vaporize. Directly related to a substance’s vapor pressure; at a given temperature a substance with a higher vapor pressure vaporizes more readily than a substance with a lower vapor pressure.
W
A measure of the ability of a fiber or substance to take up water and swell.
Wear is the damaging, gradual removal or deformation of material by contact between solid surfaces. Abrasive wear is the loss of material by the passage of hard particles over a surface. Erosion refers to mechanical causes of wear, while corrosion is the result of chemical damage.
Wetting is the ability of a liquid to maintain contact with a solid surface, resulting from intermolecular interactions, when the two are brought together. The degree of wetting (wettability) is determined by a force balance between adhesive and cohesive forces. Wettability is the tendency of one fluid to spread on, or adhere to, a solid surface in the presence of other immiscible fluids. Wettability refers to the interaction between fluid and solid phases, in this interaction the solid attempts to form a common interface with the liquid which comes into contact with it. It can be understood as the ability of a solid surface to reduce the surface tension of the liquid in contact with it such that this liquid spreads over the surface and wets it. Wettability affects relative permeability, electrical properties, nuclear magnetic resonance relaxation times and saturation profiles in the solid. One measure of the wettability by a particular liquid is the contact angle. Wettability is commonly measured for oil production and mining operations, and in a minor extent for multiphasic reactors.
Wood chips produced by chipping whole trees, usually in the forest, so that the chips contain both bark and wood.[a] They are frequently produced from the low-quality trees or from tops, limbs, and other logging residues.
X
A polysaccharide made from units of xylose and main constituent of hemicellulose, found in plant cell walls and some algae.
A monosaccharide sugar of the aldopentose type, containing five carbon atoms and including an aldehyde functional group (C5H10O5). It is the main constituent of xylan, which is the main component of hemicellulose.
Y
The point on a stress–strain curve that indicates the limit of elastic behavior and the beginning of plastic behavior. Yielding means the start of breaking of fibers. Yield stress would be the specific amount of force needed to switch between elastic and plastic behavior for a given material.
Measures the stiffness of material and describes the relationship between stress and strain in the linear elastic regime of a uniaxial deformation (extension or compression). Also referred to as the modulus of elasticity.