Date: 2009/09/16
Purpose
This is a continuing series of tests to explore the relationships between tar production and various critical measurements in the reactor. The goal is to be able to use temp and pressure readings for gasifier diagnostics and establish a formal set of "conditions needed" for clean gas production. Our hypothesis is that we can most accurately correlate tar production with temps maintained at the reduction restriction, which approximately measures how well x temp has spread and filled the hearth area for tar cracking.
This run used the same tar testing methodology and pressure setpoint experimental design as used on the Instrumented Walnut Shell Run 082409.
Results from the tar testing will be posted shortly.
The primary change in this run was a switch to softwood chips from scrap lumber (which we believe to be pine and douglas fir). The wood chips were made with a commerical disk chipper, then the fines screened out.
Methods
This run was intended to repeat the same conditions and method of the 08/24/09 run with softwood chips. A previous run on 8/31/09 ran into issues with fuel binding in the long auger which lead to only a partial run. For this run the auger was switched to the short auger/drying bucket design (as used for the TOTTI) (the auger remained strictly for reactor filling, the cowling gas->drying bucket pathway was not connected).
Gas out flowmeter was switched from a union-based flowmeter to hardwelded flowmeter (1.5" pipe, 0.76" orifice).
Fuel
Softwood Chips
- bulk density: 195 kg/m3 (wet) (3 sample average, 1L vessel)
- void space: 53% (water in 1L vessel)
- moisture content: 12.4% dry basis, 11.0% wet basis (microwave method)
Start Up
Experimental Run
Tar Sampling
Results
Fuel and Air Mass Flow
With measurements taken for this run we can compute the air to biomass mass flow ratio.
A figure of 1.6 kg of air per 1 kg biomass is provided on Modeling Gasifier Mass Flow. Measurements from this run allow us to compute this value (integrated over the entire run).
The run comsumed 83% of a hopper barrel of softwood chip fuel over a run of roughly 3 hours 20 minutes.
This is 0.0648 m^3 of fuel (62 cm * pi * (36.5/2 cm)^2) or 12.64 kg wet (0.0648 m^3 * 195 kg/m^3) or 11.25 kg dry (12.64 kg -12.64 kg * 11.0%).
Integrating airflow measurements over the entire run gives 13.66 m^3 input air or 16.4 kg air (13.66 m^3 * 1.2 kg/m^3).
Dividing air input over wood input: 16.4 kg air/11.25 kg dry wood = 1.46 kg of air per 1 kg biomass.
This figure is very close to the expected value. Note, however, that there are a number of places for introduced error, especially from the low flow/low resolution region of the air flowmeter.
Critical Temperatures
Reactor Flows
Gas flowmeter replaced. Gas out compensation still needs updated (do not use for calculations).
Reactor Vacuum
Contour Plot of Vertical Temperature Distribution with Time
Reactor Conditions
Measured Tar Correlations with Reactor Conditions
The saturation meaurement for these exceded the detectable upper bound on a number of the higher tar concentration samples. Black line is tred temperature scaled to 600-900°C bottom to top.
Run Description
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Run Name: |
Instrumented Softwood Chip Run |
Run Location: |
Shipyard, Berkeley, CA |
Operators: |
Bear, Michael |
Date: |
09/16/09 |
|
|
Fuel |
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Type: |
Softwood Chips (Scrap Lumber) |
Moisture Content: |
12.4% dry basis, 11.0% wet basis (09/16/09) |
Angle of Repose: |
ND |
Ash Content: |
ND |
Void Space: |
53% (water in 1L vessel) |
Bulk Density: |
195 kg/m3 (wet) (3 sample average, 1L vessel) |
|
|
GEK |
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Version: |
v3 |
Reactor Type: |
Imbert |
Air Nozzle Size: |
3/8" street 90°C with 3/8" cap drilled on center with 5.5 mm dia. hole, 2.75" above reduction top |
Reduction Cone Height: |
6 |
Top Reduction Diameter: |
3 |
Bottom Reduction Diameter: |
6 |
Tar Fence: |
yes |
Tar Fence Height: |
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Details: |
|
Filter: |
v3 |
Filter Media: |
New char, 1/8"-1" (walnut/mesquite) |
Fill Height: |
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Details: |
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Gas Motive Force |
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Ejector |
yes |
Jet Nozzle Type (eg barb, plug): |
drilled plug |
Jet Exit Position: |
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Fan |
no |
Power Source/Voltage: |
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Engine |
no |
Make: |
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Model: |
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GCU Setup Form
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Run Name: |
Instrumented Softwood Run |
Date: |
09/16/09 |
GCU Version: |
1.0 |
Firmware: |
in development (PID control of reactor with servo controlled ejector air, timed grate shaking (1 min intervals, ~40° fwd/back rotation) |
|
Use |
Thermocouples: |
|
TC0 |
T_bred - bottom of reduction - 1" in from cone bottom, through manometer port |
TC1 |
NA |
TC2 |
T_tred - top of reduction - inside 1/4" mild steel pipe quarter round, welded closed and positioned on the top edge of the reduction cone |
TC3 |
T_air_in - air in - inside air riser, through hole drilled co-axially with the riser tube through street 90°. 1 1/2" below top of riser. |
TC4 |
T_comb - combustion - first TC of profile assembly. centered by ring rod assembly, 1" in front of air nozzle hole, at same elevation. Sheathed in 2" length of alumina tube, extending 1/2" below TC (1/4" OD, 1/8" ID). |
TC5 |
T_1in - 1" above combustion. 2nd TC of assembly... |
TC6 |
T_2in - 2" above combustion. |
TC7 |
T_3in - 3" above combustion. |
TC8 |
T_4in - 4" above combustion. |
TC9 |
T_6in - 6" above combustion. |
TC10 |
T_8in - 8" above combustion. |
TC11 |
T_gas_out - installed in cowling gas exit port |
TC12 |
T_flare - installed in 1 1/2" tangential entrance tube |
TC13 |
T_gas_flowmeter - installed in 1 1/2" to 1/2" reducing T just after filter, before union based gas flowmeter |
TC14 |
NA |
TC15 |
NA |
Drivers: |
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FET BANK 1: |
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VOLTAGE |
12 V |
FET0 |
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FET1 |
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FET2 |
Grate Fwd Relay (30A automotive) (FET # not confirmed) |
FET3 |
Grate Rev Relay (30A automotive) |
FET BANK 2: |
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VOLTAGE |
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FET4 |
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FET5 |
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FET6 |
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FET7 |
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Servos: |
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SERVO1 |
Ejector Air Control |
SERVO2 |
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SERVO3 |
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Pressure: |
Part (7002,5004,4006,7007,5010,7025,5050) |
P0 |
7007 - P_comb - pressure at combustion, via profile assembly |
P1 |
7007 - P_reactor - taken from reactor manometer port |
P2 |
7002 - P_gas_out - gas out flowmeter differential pressure |
P3 |
7002 - P_air_in - air in flowmeter differential pressure (flowmeter installed on V3 air cowling inlet) |
I/O: |
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RS-232 |
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CAN-BUS |
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ANALOG0 |
P_filter sensor input from breadboard (7007)
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ANALOG1 |
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ANALOG2 |
Auger plunger on sense (12V motor line, through voltage divider)
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ANALOG3 |
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Frequency Counter |
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