Patent GB-750792-A (GB)
Title: Improvements in or relating to conversion of residual hydrocarbon oils
IPC: C10G9/32
Filed: 1952-05-23
Abstract: Olefines, diolefines and aromatic hydrocarbons are prepared from residual hydrocarbon oils containing substituents which do not vaporize at ordinary pressures without cracking, by a process comprising mixing the residual oil with a sufficient amount of highly heated inert or substantially inert finely divided solid particles to heat the oil to above cracking temperature, passing the resulting vaporous mixture through a tubular reaction zone at a relatively high velocity so that the time of contact between the oil being treated and the solid particles is about 0.1 to 10 secs., separating the solid particles from the reaction products, mixing at least part of these solids with air in a tubular burning zone wherein the velocity of the gas is between 10 and 100 feet/sec. whereby coke deposited on the solid particles during the cracking is burnt-off and the solid particles are <PICT:0750792/IV(a)/1> heated to an elevated temperature, separating the solids from the combustion gases and recycling them at least in part to the inlet of the tubular reaction zone, the temperature of the heated solids leaving the burning zone being such as to give a temperature above the cracking temperature when the heated solids are mixed in the residual oil feed at the required concentration.  The residual oil may comprise reduced crude oil, tar, pitch or heavy cycle stocks.  The finely divided solids may be of silica, sand, clay, coke or spent cracking catalyst.  In the preferred method, preheated residual oil at about 840 DEG  F. is fed via line 10 into a tubular reactor 12 having horizontal and vertical portions 16, 17. Finely divided heated solids are introduced into the oil feed from a stand-pipe 13 via a valve 14 to heat the oil to cracking temperature; also steam may be introduced at 15.  Cracking temperatures between 1200 DEG  and 1600 DEG  F. may be used. Pressures of 10-50 lb./sq. in. are preferably used in the reactor but other pressures including sub-atmospheric pressures can be used.  The vaporous products are quenched to below 1100 DEG  F. and fed to a cyclone separator 18; the quenching may be by oil, gas or water introduced via line 20, 22 or 24.  The quenched product vapours leave the separator by outlet 19 while the separated solids pass into stand-pipe 26.  When coke particles are used initially, coke formed in the cracking and in excess of process requirements may be withdrawn at line 48.  In general, the separated solid particles pass a valve 28 to be picked up by air introduced through line 32 and the resulting suspension is passed through a tubular heater 34 where coke produced in the cracking is burnt. Air may be introduced at intermediate points as at 37.  The hot steam at up to about 1800 DEG F. passes to a separator 36 from which the combustion gases leave via line 38 while the separated hot solids fall into standpipe 13 for re-use in the cracking stage. If desired, cracking conditions within the tubular reactor 12 may be modified by feeding solid particles to intermediate points therein either from standpipe 13 via line 64 or from standpipe 26 via lines 56, 59 and 60.  This allows treatment of highly refractory oil stocks in the initial section of the reactor and treatment of less refractory material, introduced at 61 or 66, in a later section of the reaction.  Also, an oil introduced into the inlet section may be cracked at high temperature to yield olefines and additional oil introduced into a later section may be cracked at a lower temperature to give gasoline.  Solids from standpipe 26 may also be introduced into the reactor at 58 to reduce temperature drop. An example describes the cracking of an oil of API gravity 5 DEG , initial B.P. of about 1100 DEG  F. and a Conrad carbon content of about 10 wt. per cent, at about 1355-1260 DEG  F., using heated coke particles and ethylene is recovered as main product. Specification 593,418, [Group III], is referred to.ALSO:<PICT:0750792/III/1> Olefines, diolefines and aromatic hydrocarbons are prepared from residual hydrocarbon oils containing substituents which do not vaporize at ordinary pressures without cracking, by a process comprising mixing the residual oil with a sufficient amount of highly heated inert or substantially inert finely divided solid particles to heat the oil to above cracking temperature, passing the resulting vaporous mixture through a tubular reaction zone at a relatively high velocity so that the time of contact between the oil being treated and the solid particles is about 0.1 to 10 secs., separating the solid particles from the reaction products, mixing at least part of these solids with air in a tubular burning zone wherein the velocity of the gas is between 10 and 100 feet/sec. whereby coke deposited on the solid particles during the cracking is burnt-off and the solid particles are heated to an elevated temperature, separating the solids from the combustion gases and recycling them at least in part to the inlet of the tubular reaction zone, the temperature of the heated solids leaving the burning zone being such as to give a temperature above the cracking temperature when the heated solids are mixed in the residual oil feed at the required concentration.  The residual oil may comprise reduced crude oil, tar pitch or heavy cycle stocks. The finely divided solids may be of silica, sand, clay, coke or spent cracking catalyst.  In the preferred method, preheated residual oil at about 840 DEG F. is fed via line 10 into a tubular reactor 12 having horizontal and vertical portions 16, 17.  Finely divided heated solids are introduced into the oil feed from a stand-pipe 13 via a valve 14 to heat the oil to cracking temperature; also steam may be introduced at 15.  Cracking temperatures between 1200 DEG F. and 1600 DEG F. may be used.  Pressures of 10-50 lbs./sq. in. are preferably used in the reactor but other pressures including subatmospheric pressures can be used. The vaporous products are quenched to below 1100 DEG F. and fed to a cyclone separator 18; the quenching may be by oil, gas or water introduced via line 20, 22 or 24.  The quenched product vapours leave the separator by outlet 19 while the separated solids pass into stand-pipe 26.  When coke particles are used initially, coke formed in the cracking and in excess of process requirements may be withdrawn at line 48.  In general, the separated solid particles pass a valve 28 to be picked up by air introduced through line 32 and the resulting suspension is passed through a tubular heater 34 where coke produced in the cracking is burnt. Air may be introduced at intermediate points as at 37.  The hot stream at up to about 1800 DEG F. passes to a separator 36 from which the combustion gases leave via line 38 while the separated hot solids fall into standpipe 13 for re-use in the cracking stage. If desired, cracking conditions within the tubular reactor 12 may be modified by feeding solid particles to intermediate points therein either from standpipe 13 via line 64 or from standpipe 26 via lines 56, 59 and 60.  This allows treatment of highly refractory oil stocks in the initial section of the reactor and treatment of less refractory material, introduced at 61 or 66, in a later section of the reaction.  Also, an oil introduced into the inlet section may be cracked at high temperature to yield olefines and additional oil introduced into a later section may be cracked at a lower temperature to give gasoline.  Solids from standpipe 26 may also be introduced into the reactor at 58 to reduce temperature drop. An Example describes the cracking of an oil of API gravity 5 degrees, initial B.P. of about 1100 DEG F. and a Conrad carbon content of about 10 wt. per cent, at about 1355-1260 DEG F. using heated coke particles and ethylene is recovered as main product.  Specification 593,418 is referred to.