Pyrolysis process for simultaneously conveying and agitating cracking feedstock within a screw

Abstract

A pyrolysis process is incorporated with a pyrolysis furnace in the process. The pyrolysis furnace comprises an upper screw and a lower screw juxtaposed to the upper screw to smoothen the thermal cracking process, with each blade helically formed on the screw shaft being notched in the periphery of the screw blade to form a plurality of bifurcated fins on the blade, such that besides the conveying of feedstock in the screw as driven by the blade, the bifurcated fins may serve as agitating elements, thereby simultaneously conveying the feedstock and agitating the feedstock for increasing the production efficiency of the pyrolysis.

I claim: 
     
         1 . A pyrolysis process incorporating a pyrolysis furnace in the process, said pyrolysis furnace comprising an upper furnace and a lower furnace juxtaposed to and positioned under the upper furnace, a screw having at least a blade helically formed on a screw shaft rotatably mounted in each said upper furnace or lower furnace, a duct connected between the upper furnace and the lower furnace and also serving as a chimney between the lower furnace and the upper furnace, with each said screw driven by a motor, and at least a heating device disposed around each said screw for heating the feedstock as conveyed within the screw, a feed port formed on a leftmost end portion of the upper furnace for feeding tire chips into the upper furnace, a gas outlet formed on a rightmost end portion of the upper furnace for leading gasified product outwardly to be separated as condensed cracking oil and uncondensed cracking gas, and a discharge port formed on a left end of said lower furnace for discharging carbon black as produced. 
     
     
         2 . A process according to  claim 1 , wherein said upper furnace. includes: a first preheating chamber, formed on a left position of the upper furnace for preheating the feedstock as fed into the upper furnace, a second preheating chamber formed on a right side of the first preheating chamber for further preheating the fed feedstock, a melting chamber formed on a right side of the second preheating chamber for melting the feedstock adapted for thermal cracking of the preheated feedstock, a first gasification chamber formed on the right end of the upper furnace and on a right side of the melting chamber for producing gasified products after pyrolysis cracking, which will be led outwardly through the gas outlet; and a second gasification chamber formed on the right end of the lower furnace and positioned under the first gasification chamber and fluidically communicated with the upper furnace through the duct, a first drying chamber formed in the lower furnace on a left side of the second gasification chamber for drying and removing a gasified residual oil after a gasification step, a second drying chamber formed on a left side of the first drying chamber for further drying and removing the residual oil of the gasified product, and a cooling chamber formed on a left end portion of the lower furnace and on a left side of the second drying chamber for cooling the dried product, including carbon black which is discharged through said discharge port formed on a left end of the lower furnace. 
     
     
         3 . A process according to  claim 2 , wherein said upper furnace comprises a first driving motor operatively driving the screw of upper furnace rightwardly in order to drive the feedstock from the left side towards the right side adjacent to the gas outlet; and said lower furnace comprises a second driving motor operatively drives the screw of lower furnace leftwardly from the right end of the lower furnace towards the left end of the lower furnace for discharging the carbon black through the discharge outlet after the pyrolysis. 
     
     
         4 . A process according to  claim 1 , wherein each said furnace comprises a plurabity of bifurcated fins formed on each blade of each screw, each said bifurcated fin formed on the blade helically formed on a shaft in each screw, includes a first fin member protruding leftwardly and a second fin member protruding rightwardly opposite to the first fin member for agitating a feedstock in each screw. 
     
     
         5 . A process according to  claim 4 , wherein each said bifurcated fin has a depth in said blade, said depth of each said fin being equal to 0.2 R, of which R is the radius of said blade. 
     
     
         6 . A process according to  claim 4 , wherein each said fin member is formed or bent from a blade surface for an angle ranging from 120 to 150 degrees.