Tuesday, 12 April 2016

First dissolving experiments

The first experiments with dissolving horse meat, using different acids and catalysts.

Experimental setup

Catalysts used:
  1. Potassium dichromate K₂Cr₂O₇. Solution 1 gram mixed to 50 ml tap water.
  2. Silver sulphate Ag₂SO₄. Solution 1 gram in 50 ml acid
Acids used:
  1.  Sulphuric acid H₂SO₄, 1.8 g/ml
  2. Hydrochloric acid HCl in water solution, 37.5 %
  3. Hydrochloric acid HCl in alcohol solution, 1.25 M
All the experiments were conducted in a similar way. First catalyst solution was poured in the test vessel. On top of this, the acid was added, and finally 5 grams of horse meat in small pieces. The heat of catalyst-acid-meat solution was measured with infrared thermometer.

The test setup also included a peltier element SP1848 attached to the bottom of the test vessel. The element sat on a heat sink that was cooled with a fan. Produced voltage was measured with a multi-meter. The heat conduction path between peltier element and test vessel was reasonably good, but not perfected with silicon paste of such.

 Experiment 1 

Catalyst: K₂Cr₂O₇ solution, unknown amount, maybe 10 ml
Acid: H₂SO₄, 50 ml 

Strong heating to 72 °C was observed after adding acid to catalyst. Adding meat increased to heat slightly to 79 °C, with voltage over Peltier element reaching 250 mV at highest. The meat dissolved completely in very short period of this, perhaps one minute. The color of resulting sludge was very dark red, almost black.

Afterwards, it was considered a mistake to add the meat immediately after acid, as the effect of meat heat was shadowed by heating caused by catalyst-acid reaction.

Experiment 2

Catalyst: K₂Cr₂O₇ solution, 10 ml
Acid: 37.5 % HCl, 50 ml

Compared to previous experiment, very little heating was observed after adding acid to catalyst - only 29 °C was observed. The meat did not seem to dissolve at all, not did it produce heat. The experiment was terminated after waiting for maybe two minutes.

The different between this and the first experiment caused great concern. It was theorized that the acid solution was too old and had somehow lost its potency.

An observation unrelated to the experiment was made. The soda used to neutralize the acid afterwards caused the solution to cool down to 8 °C.

Experiment 3

Catalyst: K₂Cr₂O₇ solution, 10 ml
Acid: HCl 1.25 M, 50 ml

This experiment went similarly to experiment 2. It was (weakly) concluded that hydrochloric acid is not suitable for this project.

After the experiment, some Ag₂SO₄ was added to the solution, just to quickly test if this catalyst could improve the matters. No heat production was observed.

Experiment 4

Catalyst: Ag₂SO₄ solution, 10 ml
Acid: H₂SO₄, 50 ml

No great heat production was observed after adding acid to catalyst. Adding meat caused increase to temperature, with 42 °C observed at highest. Voltage over Peltier element was 42 mV. The meat was visibly dissolving and becoming black on the edges. The experiment was terminated after about 10 minutes, with a large portion of meat still remaining. The color of solution was whitish pink.

This experiment was considered relatively successful since some heat was produced and the reaction did not proceed too fast.

Experiment 5

Catalyst: K₂Cr₂O₇ solution, 10 ml
Acid: H₂SO₄, 50 ml

This was a repeat experiment of experiment 1, in order to replicate the heat production on adding acid, and to measure heat produced by dissolving meat alone.

Adding acid to catalyst caused temperatures above 80 °C. The solution was left to cool until its temperature was at 25 °C before meat was added.

Adding meat resulted in temperature rising to 31°C, with voltage over Peltier element at 34 mV. This went on for maybe 5 minutes, after which temperature dropped somewhat, even though the piece of meat was not completely dissolved.
Note that this experiment was conducted after sunset, when outside air coming in from the window was substantially colder than during the other experiments - maybe 5 °C difference. Also note that the meat was in one 5 gram piece this time.


In light of different between experiment 1 and experiment 5, probably all the combinations did work; the great amount of heat in the first reaction just set unrealistic expectations.

The method used here does not produce very useful amounts of power. The amount of heat generated was below expectations.

It could be useful to  have instruments for voltage and temperature that are connected to computer taking automated longer time series.

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