Cracking, thermal reaction chambers

Cracking still the combined equipment-furnace, reaction chamber, fractionator, for the thermal conversion of heavier feedstocks to lighter products. 

Kerosene, gas oils and full oils can be partly cracked into gasolines, where their heavy hydrocarbon molecules are broken down into light hydrocarbon molecules. This is done with coil furnaces, at a temperature above 750°F. Then at a pressure of 10 to 17 pounds per square inch they are sent into reaction chambers, where the molecules are broken down. The gasoline yield from this thermal cracking is 55-70% for kerosene, 40-55% for gas oils, 30-40% for fuel oils. The residues are bitumens and carbonaceous products similar to coke. 

MithoiT and Schimansky, Reaction Chambers on Thermal-cracking Units, Oil Gas J., Nov. 6, 1941, p. 135. 

In the Thermofuel process the first reaction occurs in the pyrolysis chamber where the plastic is thermally pyrolyzed, causing random scission of carbon chain lengths. While secondary reactions occur in the catalytic converter (i.e. catalyst tower) where shorter carbon chains are reformed and further cracking of longer carbon chains occnrs such... 

Ozmotech have developed a Thermofuel process whereby waste plastic is converted into diesel by thermal degradation in the absence of oxygen. In this process the plastic waste is first melted and then cracked in a stainless steel chamber at a temperature of 350-425°C under inert gas (nitrogen). The catalytic reaction tower is designed in such a way that hot pyrolytic gases take a spiral or zigzag path to maximize contact area and time with the metal catalyst. The metal catalyst cracks hydrocarbon chains longer than C25 and reforms chains shorter than Ce. This leads to the formation of saturated alkanes. 

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