Monday, 22 July 2013

Comparison of Wood pellet standards

Comparison of ISO, IWPB and PFI pellet standards
Mr. Staffan Melin has kindly compiled this piece of information to compare THREE major wood pellet standards ISO, IWPB (I1, I2, I3) and PFI Pellet Standards A. This information should serve as a baseline for any wood pellet-related designs as it is widely referred to in the wood pellet markets.

For ISO and IWPB, Net calorific value (NCV) is expressed in constant pressure and in as-received (a.r.) basis. The range is 16.0 to 16.5 GJ/tonne.
For American PFI, however, the calorific value is expressed in gross calorific value at constant volume, and provided NO weight basis to adhere to.

For the wood pellets that I have received from Pinnacle Renewable Energy Group, they have NCV of ~18 GJ/tonne, a lot better than the standard. Their wood pellets are made from mainly pine wood residues.
I'm thinking the lower NCV standard is meant to suit a wider range of biomass pellets made from non-wood materials, such as agricultural residues and municipal waste. These non-wood materials have lower reported NCV of around 14-17 GJ/tonne.

For PFI standard, the heating value is not given because according to the standard,
there are no specific grade requirements for heating value, however densified fuel manufacturers must provide a minimum higher heating value guarantee on quality marked product when these standard specifications are used in conjunction with the PFI standards.

Note on unit conversion:
1 GJ/tonne = 1 MJ/kg
1 GJ/tonne = 2326 BTU/lb
1 GJ/tonne = 4168.6 cal/g

References:
  1. ISO/DIS 17225-2: Solid biofuels -- Fuel specifications and classes -- Part 2: Graded wood pellets
  2. IWPB Industrial pellets specifications - Final
  3. Pellet Fuels Institute Standard Specification for Residential/Commercial Densified Fuel, 2011

Friday, 19 July 2013

Technical Presentation about Enzymatic production from fuels & chemicals from lignocellulosic resources

I went to a technical presentation by Dr. Lisbeth Olsson at UBC Forest Science Center today morning.

The title of her presentation is: 
Enzymes and microorganisms in the service of producing fuels, chemicals and material from lignocellulosic resources


The presentation room where Dr. Olsson was presenting
Her research are:
  1. Identify and design enzymes
  2. Optimization and investigation of the physiological properties of microorganisms, in particular, yeast
She mentioned that lignocellulosic materials are very complex and difficult to break down, although there are methods to break down the lignocellulosic complex. One of the well-established method is enzymatic hydrolysis of lignocellulose.

She is looking for enzymes to:
  1. degrade plant cell wall materials to feed sugar platform to produce ethanol
  2. modify plant cell wall material to produce custom-made bioploymers (bio-plastics)
  3. upgrade plant cell wall material to more valuable products, especially cinnamic acid related compounds
In her project with Sida and FIRI, she obtained microorganism samples from Vietnam to obtain fungal strains and yeast strains. Through a series of selections, she identify the enzyme feruloyl esterases which is capable of cleaving the carboxylic ester bonds. The carboxylic ester bonds are the primary bonds that bound cellulose and lignin together. 

Through process optimization experiments, she showed that the ethanol yield can be increased by 50% by applying feeding propagation of lignocellulosic hydrolases. 

Dr. Olsson also look into improving the cellular robustness to increase the yeast's ability to maintain its performance in face of perturbation and uncertainty. To increase the cellular robustness in acetic acid stress, a strain of yeast from vinegar is obtained and tested.

To remove inhibitors, mainly the toxic phenolic compounds, pathways of bio-conversion of phenolic precursors are investigated. She concluded that conversion, in general does not indicate detoxification, but some pathways are more preferable to convert toxic substrates to non-toxic ones.

Overall, Dr. Olsson stressed that we, as a global community in bio-economy, are moving towards high gravity processes to produce higher volume of bioproducts. Running high gravity processes is tricky thing to do. It can be done more effectively if we increase the physiological understandings of the microorganisms.

Thursday, 18 July 2013

Calculator for Safe Storage time and Integration of Germination over Storage time model

 HGCA, Home Grown Cereals Authority (UK), subsidary of United Kingdom Agriculture and Horticulture Development Board (AHDB)
HGCA Quality Calculator for Safe Storage time
http://data.hgca.com/calculator/

Sadly, I cannot find the reference to calculation steps they use to calculate the safe storage time. I could  use that piece of information to explain my integration of calorific value over storage period.

YEAH, I found a paper that uses the same concept my supervisor, Dr. S suggested me to use to integrate the calorific value over storage period. Dr. S mentioned that he got the idea from a method that is used in estimating the germination percentage of grain over storage. I'm so thrilled!
http://www.plosone.org/article/fetchObject.action?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0062868&representation=PDF

A number of symbols and their definitions
  1. Thermal time (TT) model: Predict the effect of temperature on seed germination by assuming a range of temperatures, the base temperature for germination (T_b) is constant and the thermal time required for germination of a given fraction of seeds is a normal or log normal distribution among seeds in a population.
  2. Maximum Lifetime Threshold (MLT): assume that there is a maximum potential lifetime for each seed, which distributes normally among individual seed in a population, and that the time to germination of a given seed is inversely proportional to the difference between the aging time and the maximum potential lifetime of that seed.
TT model
1/tg     = germination rate
g           = germination percentile
T          = linear function of temperature at a suboptimal range
ΘT(g) = thermal time to germination of a given percentage g and T. It is found that assumption of a log normal distribution of ΘT(g) is applicable for germination prediction of aspen seeds, i.e.
probit(g) = (ln((T - Tb) x tg ) - ln(ΘT(50)))/σp,max
Tb       = the base temperature

MLT model
p         = aging time
pmax(g) = the maximum potential lifetime above which seed germination cannot occur for a given percentage g and is assumed to be normally distributed among seeds in a population
Θa       = an "aging time constant"

Aging thermal time model
ΘAT     = aging thermal time
ΘNT     = normalized aging thermal time


Saturday, 6 July 2013

ASABE Citation Guide Summary

Based on Style Guide for ASABE Technical Publications
Further reference: ASAE Standard EP285.7: “Use of SI (Metric) Units.”

Numbers

  1. From one to nine, use words, BUT always use digits for values followed by abbreviated units.
    e.g. Use 5 mL of water
  2. From ten onward, use digits.
  3. Two numbers occurs as adjacent, spell out the first one
    e.g. There were thirty 9 mm holes in the first section
  4. When a number BEGINS a sentence, SPELL IT OUT or rewrite the sentence
    e.g. Fifty samples were prepare.
    OR We prepared 50 sample.

Unit of Measurement

  1. Express all units of measure in SI (metric) units
  2. There should be a space between the number and the unit, EXCEPT for percentage and degrees
    e.g. 5 g; 20 ha
    e.g. 37%; 27°C 
  3. In a series of measurements, indicate the unit at the end, EXCEPT for percentages and degrees:
    e.g. 3, 6 and 8 cm
    e.g. 2°C to 10°C (NOT 2 to 10°C); 15% to 25% (NOT 15 to 20%)
  4. Use a comma for four-digit and larger numbers:
    e.g. 10,000 kg (NOT 10000 kg)
  5. Express derived units in exponent form with spaces between the elements of the derived unit
    e.g. 12 kg m^-2

Dates

  1. Write all dates in day-month-year format, with no punctuation and with names, rather than numbers, for the months:
    e.g. 12 January 2002
    e.g. 29 April to 17 May
    e.g. 4 to 16 August
  2. In tables, the names of months may be abbreviated to save space, as:
    e.g. Jan., Feb., Mar., Apr., May., Jun., Jul., Aug., Spet, Oct., Nov., Dec.

Abbreviations in Text

  1. Spell out abbreviations that might be unfamiliar to the ASABE audience ONLY at their first occurrence.
  2. Form plurals for abbreviations without an apostrophe
    e.g. PCs, CVs, PhDs
  3. Omit periods after abbreviated units (expect "in." for inch);
    e.g. 5 m, 3.5 in., 30 cm
  4. Abbreviate units only after a numeric value:
    e.g. 24 h v.s. Several hours later
Common abbreviations:
dry basis                 d.b.
standard deviation   SD
wet basis                 w.b.

Abbreviations in References

  1. Do not abbreviate any words in titles of articles, chapters, books, or dissertations.
  2. Use conventional abbreviations (not postal abbreviations) for names of states and territories.
    ONLY abbreviate names of states and territories in references! 
  3. ASABE journals are abbreviated as Trans. ASABE, Applied Eng. in Agric., J. Agric. Safety and Health, and Biol. Eng. Trans.
See complete list of abbreviation for journals as well as states and territories in the Style Guide (Link in the 1st line)

Figures

ASABE applies the term "figure" to all types of illustration, including line drawings, graphs and charts, photographs, computer screen captures, etc.

Size (Note: 1 pica = 1/6 of an inch or 0.1666... in.)
For Applied Engineering in Agriculture and Transactions of the ASABE figures are general the width of a column (20 picas, ~8.5 cm, ~3.33 in.), but may be as wide as a page (41 picas, ~17.4 cm, ~6.83 in.). For other publications, make each figure no wider than the page width (for Journal of Agricultural Safety and Health and Biological Engineering Transactions, this is 28 picas, ~11.9 cm, ~4.67 in.).

Other rules
  1. Insert each figure AFTER the paragraph that first mentions it. Every figure must be explicitly mentioned in the text of the article. number figures in order of their citation in the text and refer to them as figure 1, figure 2, etc. Abbreviate the word "figure" ONLY in parentheses, e.g., (fig. 1).
  2. Type a descriptive caption below each figure. The caption may be a sentence fragment or a few sentences long.
  3. NO titles in figures.
  4. Place the legent either directly below the figure or within it.
  5. Generally, It is NOT necessary to show all the data points and coordinate rulings.
  6. If a point represents the mean of a number of observations, indicate the magnitude of the variability by a vertical line at each point.
  7. Use boldface ONLY for x- and y-axis titles. Use all capitals only when necessary (e.g., for acronyms).
  8. If a figure contains multiple elements, label them (a), (b), (c), etc., using eight point bold, and identify them in the caption (as shown in sample figure below).
  9. You may  horizontal or vertical type alignment, but NO other angles.
  10. All lines must be at least one-half point to reproduce in print and distinct from each other in appearance.
  11. Color figures will display in color in the web version, but will be printed in grayscale. Please choose colors that reproduce as distinct gray values. DO NOT use yellow. Choose DISTINCT line types (dashed, dotted, etc.) as well as different colors.
  12. Do NOT CROP IN WORD because the cropping will not be retained as the figure moves through out production process. Instead, open the figure and delete the unwanted elements, or crop the figure then cut it and "Paste Special" as a picture or metafile to eliminate the cropped materials.
  13. Please provide .jpg or .tif files of photographs in case we need to enhance the images. When using a digital camera for your photos, use at least a medium setting for quality/file size.
  14. For scans, use 600 dpi for black and white line art, and 300 dpi for color or grayscale (including photos).

 Tables

The data presented in tables should neither be duplicated in figures nor reviewed extensively in the text.
Size
For Transactions of the ASABE and Applpied Engineering in Agriculture, prepare each table to fit either one column (20 picas, ~8,.5 cm) or the page width (41 picas, ~17.4 cm). Tables in Journal of Agricultural Safety and Health and Biological Engineering Transactions should be NO wider than 28 picas, ~11.9 cm.
Other formatting rules
  1. Number the tables consecutively and refer to them in the text as table 1, table 2, etc.
  2. Supply a descriptive caption for each table
  3. Please make your table in MS Word. Do not submit tables in a graphic format.
  4. Do not include excessive text in the column headings. Place explantory information in the table caption, in the manuscript text, or in a footnote at the bottom of the table.
  5. Do not include columns of data that can be easily calculated from other columns
  6. Use horizontal rules to separate elements within a table. You may place additional rules under subheads or under heads that span two or more columns, and you may need to insert blank columns to achieve this. (as in the sample table).
  7.  Use bracketed superscripted letters ([a], [b], [c], etc.) for explanatory footnotes within the table (as in the sample table). Assign footnotes to elements within a table in a left-to-right, top-to-bottom sequence.
  8. Use asteriks (*, **) to indicate statistical significance, and explain the significance in a footnote.
  9. Use lowercase letters (a, b, c, etc.) to indicate statistical relationships among elements within a table, and explain the relationships in a footnote.

Equations

Rules on Equation
  • Do NOT derive or reproduce recognized equations; rather, cite a reference to a source and refer to the equation by its standard name. State only those assumptions and initial boundary conditions needed to understand the development of the equation.
  • For new equations, state all assumptions and initial boundary conditions and give sufficient derivation for the reader to understand the development. Show only those mathematical steps required for comprehension. Interpret the significance of the mathematics, and indicate the accuracy and range of usefulness of the equations.
Other formatting rules
Insert each equation into your manuscript at the point where you would like it to appear in the published article. Small equations may be incorporated in the text. Equations that are separate from the text are introduced by the preceding text and a colon (see the sample equation). These equations are numbered consecutively. Refer to numbered equation as equation 1, equation 2, or in parentheses as. e.g., (eq. 1)
  1. When you can, prepare equations in using standard word-processing functions, superscripting, subscripting, and the Symbol font. Other use equation-editing software such as Equation Editor or MathType. Do not create equations that become graphic elements in Word as these cannot be edited.
  2. The type style in the equation must match the type style in the corresponding text. Italicize lowercase variables. Do not italicize Greek Letters.
  3. Supply the equation number, in parentheses, to the RIGHT of the equation. Do not include the equation number within the equation editor box.
  4. Definte variables and supply SI units. If there are more than two such elements in an equation, then list them individually after the equation (as in the sample equation).

References

List all cited references at the end of the text in the References section.
Rules on General Organization of References
  • Arrange the list alphabetically by the name of the first author; for references with more than on author, further arrange the list alphabetically by the names of the second author, third author, etc,
  • List CHRONOLOGICALLY two or more references by the same author (or authors) from oldest to most recent.
  • indicate, by adding letters after the year of publication, two or more references by the same author(s) in the same year
    e.g., 2007a, 2007b
  • For use of abbreviations in references, see above in "Abbreviations in References".