GEK Wiki / Instrumented Softwood Chip Run 083109
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Instrumented Softwood Chip Run 083109

Page history last edited by bk 13 years, 6 months ago

Date: 2009/08/31




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.  The graphs at the end of the report plot tar production against this top of reduction temp, as well as other variables that might be contenders for relevant control or indicating parameters.


This run used the same tar testing methodology and pressure setpoint experimental design as used on the Instrumented Walnut Shell Run 082409.


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.


Other tests in this series are linked to from the GEK User Pages and Run Reports page.



This run was intended to repeat the same conditions and method of the 08/24/09 run with softwood chips. There were a few instrumentation and auger issues that did not yield a complete repetition of the previous run (the GCU was reset during the second ramp up/down "pyramid") and the run called short. The run should, none-the-less, yield some useful information.  What is below is still a very partial report.  It will get finished after a short vacation for the rest of this week.



Start Up


Experimental Run


Tar Sampling



Critical Temperatures

The drop in combustion temperatures at 157 min is perplexing, sensor failure may be best explaination.

Reactor Flows

The gas out lines experienced some condensation in the latter part of the run. The condensation was removed on one occasion, leading to 0 flow readings. Condensation in the lines will bias measurements. Air in measurements are unaffected.

Reactor Vacuum

Combustion pressure line was not connected until 110 min.


Contour Plot of Vertical Temperature Distribution with Time

Combustion reading is anomalous after 160 min (values caused by failure of the combustion thermocouple [oxidation]).


Reactor Conditions

The auger fuel feed had binding issues (excess of overly long chips?), leading to the long periods of the auger being on.

Tar vs. Reaction Conditions Relationships

The points with T_comb around 400°C were likely from the period after the combustion thermocouple failed (after 160 minutes above), invalidating this graph.



Run Description

Run Name: Instrumented Softwood Chip Run
Run Location: Shipyard, Berkeley, CA
Operators: Bear
Date: 08/31/09
Type: Softwood Chips (Scrap Lumber)
Moisture Content: 12.7% dry basis, 11.3% wet basis via microwave equilibrium method (08/31/09), using 7 chip sample that remained in sealed hopper for 2 days
Angle of Repose: ND
Ash Content: ND
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:  
Filter: v3
Filter Media: Char, run before, remixed
Fill Height:  
Gas Motive Force  
Ejector yes
Jet Nozzle Type (eg barb, plug): drilled plug
Jet Exit Position:  
Fan no
Power Source/Voltage:  
Engine no


GCU Setup Form

Run Name: Instrumented Walnut Shell Run
Date: 08/31/09
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)
TC0 T_bred - bottom of reduction - 1" in from cone bottom, through manometer port
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 tubethrough 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 3" length of 1/4" mild steel tube.
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
FET2 Grate Fwd Relay (30A automotive) (FET # not confirmed)
FET3 Grate Rev Relay (30A automotive)
SERVO1 Ejector Air Control
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)
ANALOG2 Auger plunger on sense (12V motor line, through voltage divider)
Frequency Counter



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