Summary of fuel analyses results for banagrass.

<p>* 'Ground' refers to the banagrass after it had been ground to a particle size of ≤200 μm.</p><p>^# Oxygen by difference</p><p>Repeatability estimated to be ≤0.5% (absolute)</p><p>Summary of fuel analyses results for banagrass.</p

Elemental conversion efficiency (C, H, N and O by difference) results for the dry bio-oil samples from banagrass pyrolysis as a function of temperature and vapor residence time (bed position, BP).

<p>Results are presented as wt% of the element in the Feedstock (daf). The standard deviation for the C and O results is ≤3.0 wt%, for H ≤5.0 wt% and for N ≤10.0 wt% (absolute).</p

Fast Pyrolysis Behavior of Banagrass as a Function of Temperature and Volatiles Residence Time in a Fluidized Bed Reactor

<div><p>A reactor was designed and commissioned to study the fast pyrolysis behavior of banagrass as a function of temperature and volatiles residence time. Four temperatures between 400 and 600°C were examined as well as four residence times between ~1.0 and 10 seconds. Pyrolysis product distributions of bio-oil, char and permanent gases were determined at each reaction condition. The elemental composition of the bio-oils and chars was also assessed. The greatest bio-oil yield was recorded when working at 450°C with a volatiles residence time of 1.4 s, ~37 wt% relative to the dry ash free feedstock (excluding pyrolysis water). The amounts of char (organic fraction) and permanent gases under these conditions are ~4 wt% and 8 wt% respectively. The bio-oil yield stated above is for 'dry' bio-oil after rotary evaporation to remove solvent, which results in volatiles and pyrolysis water being removed from the bio-oil. The material removed during drying accounts for the remainder of the pyrolysis products. The 'dry' bio-oil produced under these conditions contains ~56 wt% carbon which is ~40 wt% of the carbon present in the feedstock. The oxygen content of the 450°C, 1.4 s 'dry' bio-oil is ~38 wt%, which accounts for ~33 wt% of the oxygen in the feedstock. At higher temperature or longer residence time less bio-oil and char is recovered and more gas and light volatiles are produced. Increasing the temperature has a more significant effect on product yields and composition than increasing the volatiles residence time. At 600°C and a volatiles residence time of 1.2 seconds the bio-oil yield is ~21 wt% of the daf feedstock, with a carbon content of 64 wt% of the bio-oil. The bio-oil yield from banagrass is significantly lower than from woody biomass or grasses such as switchgrass or miscanthus, but is similar to barley straw. The reason for the low bio-oil yield from banagrass is thought to be related to its high ash content (8.5 wt% dry basis) and high concentration of alkali and alkali earth metals (totaling ~2.8 wt% relative to the dry feedstock) which are catalytic and increase cracking reactions during pyrolysis.</p></div

Volatiles residence times (seconds) at the working velocity and flow rates (LPM, STP) to achieve minimum fluidization velocity, for the four different bed positions and four temperatures used in this study.

<p>The times are derived from the volume of the freeboard alone, excluding the side-arm where the volatiles pass to the bio-oil traps.</p

Dry bio-oil yields relative to daf feedstock as a function of temperature and vapor residence time, S.D. ≤2.0 wt% absolute.

<p>Dry bio-oil yields relative to daf feedstock as a function of temperature and vapor residence time, S.D. ≤2.0 wt% absolute.</p

Schematic diagram of the variable-freeboard pyrolysis reactor.

<p>Numbers 1 through 6 show the locations of the thermocouples in the multi-point temperature probes (SS—stainless steel).</p

Bio-Oil, char and gas yields (daf) from cellulose pyrolysis, at the longest residence times (BP-1).

<p>^# Volatile bio-oil refers to the amount of bio-oil removed from the sample during rotary evaporation and is determined by analyzing the bio-oil solution by GCMS before drying and again after it is dried.</p><p>^ Indicative values derived from on-line gas analysis.</p><p>* The bias in the char yield is estimated to be ≤±2 wt% (absolute).</p><p>** 'Undetected' is derived as: 100%—(dry bio-oil + volatile bio-oil + char + CO, CO₂, CH₄ and H₂ yields).</p><p>n.d. not determined, due to instrument unavailability; n.a. not applicable; S.D. is the standard deviation.</p><p>Bio-Oil, char and gas yields (daf) from cellulose pyrolysis, at the longest residence times (BP-1).</p

Bio-oil, char and gas yields (daf) from cellulose pyrolysis, at the shortest residence times (BP-4).

<p></p><p>^# Volatile bio-oil refers to the amount of bio-oil removed from the sample during rotary evaporation and is determined by analyzing the bio-oil solution by GCMS before drying and again after it is dried.</p><p>^ Indicative values derived from on-line gas analysis.</p><p>* The bias in the char yield is estimated to be ≤±2 wt% (absolute).</p><p>** 'Undetected' is derived as: 100%—(dry bio-oil + volatile bio-oil + char + CO, CO₂, CH₄ and H₂ yields).</p><p>Bio-oil, char and gas yields (daf) from cellulose pyrolysis, at the shortest residence times (BP-4).</p

Permanent gas yields relative to daf feedstock as a function of temperature and vapor residence time, S.D ≤1.5 wt% absolute.

<p>Permanent gas yields relative to daf feedstock as a function of temperature and vapor residence time, S.D ≤1.5 wt% absolute.</p

Elemental analysis (C, H, N, and O by difference) results for the dry bio-oil samples from banagrass pyrolysis as a function of temperature and vapor residence time (bed position, BP).

<p>Results are presented as wt% of the bio-oil. The standard deviation of the C and O results is ≤1.5 wt% (absolute) and for H and N ≤0.3 wt% (absolute).</p