Place known mass of cardboard in reactors A and B and heat for fixed measured time intervals and record the resulting mass of wood/char after each interval, to assess the progress of pyrolysis.
30 April - Mass of A loaded with cardboard = 2014 g
Empty mass = 1962 g
Net mass of cardboard = 52 g (may include some residual water)
reactor A dimensions: 5.3 cm diameter x 22 cm height; 485 cm3
density of sample = 52/485 = 0.107
elapsed time top cap temp (C) , mid-reactor temp, bottom cap temp, notes
0 min 29.5, —, —
2 min 55, 200, —
6 min 71, 250, 370, start of steam at vent
10 min 78, 280, 410, steam dissipates in 4" above vent.
20 min 119, 308, 476, smoke dissipates in 12"
30 min 150, 315, 497, at 24 min, smoke persists
removed from heat at 30 minutes
35 min 125, 100, 306
40 min 118, 80, 220
final mass = 1978 g; remaining sample = 1978 - 1962 = 16 g (16/52 = 30.8%) residual sample is easily crumbled to lower half of reactor, but some remains cardboard-like in strength and color.
Mass of B loaded with cardboard = 721 g
Empty mass = 337 g
Net mass of cardboard = 384 g
reactor B dimensions: 15.6 cm diameter x 28 cm height; 5350 cm3
density of sample = 384/5350 = 0.072
elapsed time top cap temp, mid-reactor, bottom temp, notes
0min 32, —, —
2 min 84, 205, —, steaming vigorously
5 min 110, 225, —, persistent smoke
removed from fire after 7 minutes due to excessive smoke
8 min 98, 174, —, cool-down
10 min 84, 125, —, cool-down
final mass = 670 g; remaining sample = 670 - 337 = 333 g (333/384 = 87%)
1 May - Add ¼-inch OD copper tubing and brass fitting (two feet of copper tubing); new lid mass = 162 g. Old lid mass 52 g; net increase in tare weight = 162 - 52 = 110 g
elapsed time lid temp, mid-reactor temp, notes
7 min restart heating, now with vent tube and water trap
9 min —, —, bubbling vigorously
10 min 69, 130
12 min 83, 176, replaced water trap water, pyrolysis oil drips from tube; condensing in the tube; maybe I could water-cool and condense product?
15 min 95, 182
22 min 105, 197
30 115, 203
removed from fire at 30 minutes total elapsed time on flame
off-gas bubbles continue for about 1:30 after end of heating. Water trap surface is coated with brown oil trap temperature is 54C after 15 minutes of bubble-trapping (approx. volume is 400 mL). In the future, measure aspects of water trap function? net evaporation? how to quantify oil yield? The oil seems high viscosity. It has a strong wood-smoke odor
Maybe I could direct the tube to the flame zone and simply burn the gas to help heat the reactor.
Resume cooking reactor B sample, gas control valve is ½ turn open. Elapsed times are measured duration of heating, from the start of heating of the current sample.
elapsed time lid temp, mid-reactor temp, notes
30 min restart heating initial lid temp is 41C
32 61, 153
35 85, 203, some oil production at 38:00
39 103, 204
45 109, 225
50 118, 220
55 118, 227
60, 124, 219, stop heating; bubbles continue about 3:00
check reactor mass (loaded): 646 g
inspection of char: with lid removed, it smokes and begins to make embers. Reclosed promptly. Observed significant cardboard is still intact. Packed it down in the reactor
resume cooking reactor B (initially at ¼ turn open instead of ½ open)
elapsed time lid temp, mid-reactor temp, notes
60 min restart heating initial load temp is 52C
62 67, 171
65 98, 222
70 111, 219
75 126, 233, metal in vicinity of lower edge of can >400 C
80 133, 235, increased burner to ½ turn open
85 131, 250, water trap at 49C
90 138, 269
95 138, 277, reduced bubble flow
100 141, 260
105 139, 258, very few bubbles; end heating
bubble flow ceased almost immediately after removing heat
reactor final mass: 590 g
tare weight of biochar product storage container: 317 g
removed reactor B contents to storage: 457 g → 140 g net
checked reactor B empty weight: 452 g it was 447 g prior to pyrolysis 5 g increase due to tar and residues.
Of the 140 g of product, 41 g is non-friable intact but degraded cardboard pieces greater than 1 inch.
The pyrolysis oil from this process is brown, forms lumps of soot, and has a strong smoke odor. It is difficult to remove from plastic containers with soapy water, but can be emulsified with undiluted Dawn liquid soap.
Analysis of the data —> “Pyrolysis” tab