Biomass Processing

The  assessment  of  cooking  energy  cost  and efficiency  of  improved woodfuel clay  cookstoves  in Nigeria have been considered in this  study. Two improved wood burning clay  cookstove models  were compared to the 3-stone fire stove  using the  water  boiling  test  and controlled cooking  test.  The  following  parameters:  specific  fuel  consumption  (SFC), thermal efficiency,  ebulution time and cooking energy  cost  were considere as  key  indicators  for  comparison.  The results show  that  the fire  power  for  the cold starts  phases  were  7.72KW,  8.59KW  and  9.78KW  for  the stove with  grate,  modified stove without  grate  and the 3-stone open fire (TFS)  respectively.  The  thermal efficiencies  ranges  between 19-35%,  13.826.8%  and 11.7-22.8%  for  the cold start,  hot  start  and simmer  phases  for  mud stove with  grate (MSWG),  mud stove no grate (MSNG)  and three stone open fire (TFS)  respectively.  MSWG,  showed the highest  savings  potential  on wood fuel consumption with the lowest  total wood cost  of  N127.80  and sfc  of  1.632Kg of  fuel/kg of  food cooked.  While MSNG  and TFS,  have a  total  wood  fuel  cost  and SFC  of  N207.70  ,  N269.20,  and 2.141,  1.632kg of  fuel/kg of  food  cooked respectively. 

The effect of ionic liquids upon the mechanical and (bio)chemical integrity of macadamia nut shells (from Macadamia integrifolia) has been investigated. Whole macadamia nuts-in-shell are notoriously difficult to crack, and the Australian macadamia nut shells used in this study required 2240 ± 430 N of force to crack. Ionic liquids were screened for their solubility values, with 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) able to dissolve 5.5 ± 0.5 wt % macadamia nut shell. Treatment with small quantities of [Emim][OAc] resulted in weakened whole nut-in-shells that could be cracked with only ca. 46% of the displacement (0.67 ± 0.16 mm), ca. 34% of the force (760 ± 240 N) and ca. 15% of the energy (0.25 ± 0.10 J per shell) relative to no treatment. Further treatment by dissolution and precipitation of macadamia nut shell, followed by enzymatic hydrolysis with cellulase, resulted in the release of 80 ± 15% of the expected glucose content, relative to 1.3 ± 1.0% before any pretreatment.

BACKGROUND
Acetic acid is an important reagent and a precursor in chemical and material industries. It is largely manufactured from fossil resources, but with increasing environmental concerns and uncertain petroleum availability, producing organic acids from renewable biomass became a priority. Several researchers have demonstrated acetic acid production from model compounds, food products or a minor portion of lignocellulosic biomass but the simultaneous fermentation of all biomass-derived products has not been reported yet. This work demonstrates the unique capabilities of Clostridium thermoaceticum and Clostridium thermocellum in co-culture to convert most products obtained from hot-compressed water treatment of Japanese cedar into acetic acid.

RESULTS
Under an optimal pH found to be 6.5, most of cello-oligosaccharides and xylo-oligosaccharides as well as the majority of monosaccharides were completely consumed after 40 h, while the lignin-derived products, organic acids, decomposed and dehydrated compounds required 72 h to be fermented. Overall, it was found that most of the water-soluble lignocellulosic hydrolyzates were successfully transformed into acetic acid, leading to high carbon conversion efficiency of 84.9 %.

CONCLUSION
Biomass-derived compounds from hot-compressed water treatment were efficiently converted to acetic acid, a valuable intermediate for further biotechnological production of chemicals and materials to substitute fossil-derived ones.

Sugarcane bagasse is an interesting feedstock for the biobased economy since a large fraction is polymerized sugars. Autohydrolysis, alkaline and acid pretreatment conditions combined with enzyme hydrolysis were used on lignocellulose rich bagasse to acquire monomeric sugars. By-products found after pretreatment included acetic, glycolic and coumaric acid in concentrations up to 40, 21 and 2.5 g/kg dry weight bagasse respectively. Alkaline pretreated material contained up to 45 g/kg bagasse DW of sodium. Acid and autohydrolysis pretreatment results in a furan formation of 14 g/kg and 25 g/kg DW bagasse respectively. Enzyme monomerization efficiencies of pretreated solid material after 72 h were 81% for acid pretreatment, 77% for autohydrolysis and 57% for alkaline pretreatment. Solid material was washed with superheated water to decrease the amount of by-products. Washing decreased organic acid, phenol and furan concentrations in solid material by at least 60%, without a major sugar loss.

Biochar is a carbonaceous porousmaterial deliberately applied to soil to improve its fertility. Themechanisms through which biochar
acts on fertility are still poorly understood. The effect of biochar texture size on water dynamics was investigated here in order
to provide information to address future research on nutrient mobility towards plant roots as biochar is applied as soil
amendment. A poplar biochar has been stainless steel fractionated in three different textured fractions (1.0–2.0mm, 0.3–
1.0mm and <0.3mm, respectively). Water-saturated fractions were analyzed by fast field cycling (FFC) NMR relaxometry. Results
proved that 3D exchange between bound and bulk water predominantly occurred in the coarsest fraction. However, as porosity
decreased, water motion was mainly associated to a restricted 2D diffusion among the surface-site pores and the bulk-site ones.
The X-ray μ-CT imaging analyses on the dry fractions revealed the lowest surface/volume ratio for the coarsest fraction, thereby
corroborating the 3D water exchange mechanism hypothesized by FFC NMR relaxometry. However, multi-micrometer porosity
was evidenced in all the samples. The latter finding suggested that the 3D exchange mechanism cannot even be neglected in
the finest fraction as previously excluded only on the basis of NMR relaxometry results. X-ray μ-CT imaging showed heterogeneous
distribution of inorganic materials inside all the fractions. The mineral components may contribute to the water relaxation
mechanisms by FFC NMR relaxometry. Further studies are needed to understand the role of the inorganic particles on water dynamics.

Biomass is a versatile energy resource that could be used as a sustainable energy resource in
solid, liquid and gaseous form of energy sources. Torrefaction is an emerging thermal biomass
pretreatment method that has an ability to reduce the major limitations of biomass such as
heterogeneity, lower bulk density, lower energy density, hygroscopic behavior, and fibrous
nature. Torrefaction, aiming to produce high quality solid biomass products, is carried out at
200-300 °C in an inert environment at an atmospheric pressure. The removal of volatiles
through different decomposition reactions is the basic principle behind the torrefaction
process. Torrefaction upgrades biomass quality and alters the combustion behavior, which can
be efficiently used in the co-firing power plant. This paper presents a comprehensive review on
torrefaction of biomass and their characteristics. Despite of the number of advantages,
torrefaction is motivated mainly for thermochemical conversion process because of its ability
to increase hydrophobicity, grindability and energy density of biomass. In addition to this,
torrefied biomass could be used to replace coal in the metallurgical process, and promoted as
an alternative of charcoal.

The energy efficiency of torrefaction/pyrolysis of biomass to fuel/biochar was studied using conventional (slow) and microwave (low temperature) pyrolysis. Conventional pyrolysis is approximately three times as energy efficient as microwave pyrolysis, in terms of the energy required to process a unit of feedstock. However, this is more than compensated for by the higher energy content of the condensable and gaseous coproducts from microwave pyrolysis, as these can be utilized to generate the electricity required to drive the process. It is proposed that the most efficient method of torrefaction/biochar production is a combination of conventional heating with ‘catalytic’ amount of microwave irradiation.