GB770368A - Improvements in and relating to cracking equipment for heavy liquid compounds of high distilling point - Google Patents

Abstract

Apparatus for cracking heavy hydrocarbon materials such as mazout comprises a heated container having a horizontal base-plate divided by ribs into a plurality of longitudinal channels, and a reciprocating scraper which carries an ejector pipe, the operation being such that liquid hydrocarbon feed is discharged on to the hot base-plate as the scraper moves along the container in one direction, while the solid cracking-residue is scraped off the plate as the scraper moves in the opposite direction. The apparatus shown (Figs. 1 and 2) comprises a preheating chamber 16 and a cracking container 20. Hot gases from furnace 22 flow under the base plate 24 of container 20, and then pass through channels 32 into chamber 16. The gases are finally discharged through chimney 33. Mazout heated at 120 DEG C. is pumped through pipe 13 to U-shaped pipe 15 in chamber 16. The preheated liquid then flows through flexible duct 17 into rigid duct 171 which <PICT:0770368/III/1> <PICT:0770368/III/2> <PICT:0770368/III/3> <PICT:0770368/III/4> <PICT:0770368/III/5> passes through a hollow stem 18 mounted in a packed gland in the end-cover 26 of container 20. Stem 18 is attached to a scraper 34 consisting of two plates 35, 36 (Fig. 3), screwed together and defining an upper chamber 37 and a longitudinal conduit 40. A prolongation 181 of stem 18 is attached to plate 36; stem 18 and prolongation 181 being connected by pipe 44, which passes through sealing-washer 43. Prolongation 181 supports at right angles to itself an ejector pipe 47 (Figs. 4 and 5) which has nozzles 48. Both the free end of stem 18 and the free end of prolongation 181 are provided with pulling-plates 50 and 51 respectively, which are linked by cables to rings 54 and 55; and these in turn are connected by cables to a reversing motor (not shown). Scraper 34 is thereby made to move back and forth in container 20. The reversing motor which actuates scraper 34 also operates feed-pump 2. During a back stroke of the scraper, preheated mazout flows from duct 171 through chamber 37, conduit 40 and pipe 44 into prolongation 181 and thence through pipe 47 and nozzles 48 on to the ribs 49 of base plate 24, which is at a temperature of about 600 DEG C. The mazout flows into channels 60 where it is cracked to form vapours and coke. The vapours are discharged through duct 30. During the subsequent fore-stroke of the scraper the mazout-feed is inoperative, and the coke is scraped off the base-plate and transported into collector 31. During this scraping-stroke, sufficient time elapses for the base-plate to be reheated to the cracking temperature ready for a new cycle to be started.