The process defined in objective one above needs further elucidation to
clarify any misunderstandings that might occur. During the past few years we
discovered that ag-waste, particularly animal manures, could be converted to diesel fuel
like substances by reaction with water at near supercritical conditions. The focus of the
initial experiments was chicken liter. The initial reactions used tubing bomb reactors that
contained thirty-gram samples of dry chicken liter mixed with thirty grams of water. After
the tubing bombs were filled with the blended ag-waste and water. They were sealed
and immersed into a heated fluidized sand bath. The fluidized bath transferred the heat
to the tubing bombs and thus their contents. No shaking or stirring was used during
these experiments. After the tubing bombs were heated for a specified time period they
were immerse in a bath of cold water to stop the reaction. The bombs were weighted
before emptying, for mass balance. The products from the reaction are in three states: a
gas that is about 96% carbon dioxide, a aqueous liquid mixture that is about 45% waterthe
reminder are organic acids amines and alcohols, and a sticky tarry substance. The
weights of each of theses components are measure again for mass balance. The liquid
and solid portion are mixed with diesel fuel. The mixture is stirred and heated to nearly
70oC. This is the visual reflux temperature of the mixture. The hot mixture is filtered to
remove any insoluble solids. The filtrate is put in a separation flask and the aqueous
phase removed. The diesel fuel phase and aqueous phase are weighted for mass
balance. The residue was then washed with Tetrahydrofuran (THF). A significant portion
of the solid dissolves in THF. It is felt that these compounds are too polar to dissolve in
diesel fuel, but still should have some fuel value. The mass closure was done on the
mixture. This is seen in the appendix. (table 1).
2
In a second series of reactions larger samples for engine testing were run. In
these runs a four-liter autoclave was used as the reaction vessel. About 600 grams of
ground dried chicken liter was mixed with 600 grams of distilled water. The resulting
mixture has the physical consistency of “dry cookie dough”. It is fed into the reactor and
the reactor is sealed. The autoclave is lowered into its heating jacket. This is an
electrical resistance heater capable of reaching temperature in excess of 500oC. The
vessel is capable of holding pressures of 6000 psig. The reactor is equipped with a
magnetic stirrer whose rpm was adjusted at 85 rmp. The reactor and its contents heated
at nearly 3 degrees per minute. The temperature and pressure are recorded every
minute. The reactor was heated to 360oC at which time the heater was turned off. The
vessel was then permitted to cool to room temperature. When the reactor was cooled it
was noted that an internal pressure of nearly 200 psig was observed this represents the
gases produced as in the tubing bombs. The gas was permitted to escape through a
valve into a preweighted gas collection bag. This permitted a reasonably accurate mass
closure. The reactor was opened and its contents were removed. [It should be noted
that the gas collected in the collection bag was not all the gas produced during the
reaction. During the removal of the autoclave contents gas was seen bubbling from the
liquid phase. Using the weight of gas collected in the bag permitted only about 90%
mass balance. It was assumed that the missing 10% was this entrained gas so another
weight of gas to insure mass balance was assumed.] The solids were filtered from the
liquids and washed with heated diesel fuel in a large roto-vap reactor. The roundbottomed
vessel of the roto-vap was partially submerged in a hot oil bath set at 70oC.
The diesel fuel dissolved appreciable quantities of reacted ag-waste. This process was
repeated until enough fuel was obtained test the fuel in a diesel engine.