Abstract: A process for steam conversion of a hydrocarbon feedstock in the presence of a catalyst includes the steps of (a) providing a catalytic emulsion comprising a water in oil emulsion containing a first alkali metal and a second metal selected from the group consisting of Group VIII non-noble metals, alkaline earth metals and mixtures thereof; (b) mixing the catalytic emulsion with a hydrocarbon feedstock to provide a reaction mixture; and (c) subjecting the reaction mixture to steam conversion conditions so as to provide an upgraded hydrocarbon product. A catalytic emulsion and process for preparing same are also provided.

Abstract: Light olefins are produced from a hydrocarbon feedstock by a steam pyrolysis reaction in the presence of small quantities of essentially pure oxygen and selected catalytic solids to enhance the steam pyrolysis reaction, to promote the combustion of hydrogen to water and to minimize the formation of carbon oxides. The catalysts are characterized by low surface area, by non-alumina supports and by the catalytic oxides of the group IVB, VB and VIB transition metals.

Abstract: The invention relates to the protection of tubular reactors or heat exchangers against coke formation in plants for converting hydrocarbons and other organic compounds at high temperatures in the gaseous phase. The problem in such plants is that the usual steam/air cleaning processes for removing coke deposits lead to an increase in the catalytic activity of the material surfaces, which in turn shortens the service life of the plants. The object of the invention is to substantially reduce coking and to maintain the long-term passivity of steels for long operational periods.

Abstract: A steam cracking process and facility is described which comprises injection of erosive powder to effect at least partial decoking of transfer line exchangers without interrupting the steam cracking stream. The powder, preferably injected just upstream of the transfer line exchangers (TLE) (4), is separated from the cracked gases in primary gas/solid separators (5), temporarily stored in receiving drums at a controlled temperature and evacuated to a common powder storage and/or treatment module by pneumatic transfer by means of a relatively low flow of uncondensable gas. The process and facility can be used to collect solid fragments generated by injection of chemical compounds which are catalysts for the gasification of coke by steam.

Abstract: There is provided a process and a device with a convection zone (A) and a radiation zone (B) in a furnace (10), whereby the process includes: a first stage of precracking a feedstock of light hydrocarbons (1) and a second stage of final co-cracking of the mixture that is composed of this precracked light feedstock (7) and a feedstock of heavy hydrocarbons (2). The process further includes: separate heating of the two feedstock streams (1 and 2) in the convection zone (A), in which the preheating temperature of each feedstock stream remains below the initial cracking temperature in each case; precracking (5) of the preheated light hydrocarbons; mixing of precracked light hydrocarbon stream (8) while a mixed stream (9) is formed; intense heating of mixed stream (9) to a temperature that is higher than the initial cracking temperature by virtue of the fact that the mixture is introduced into the radiation zone (B) of the furnace (10); and cooling (15) of cracked gases outside the furnace (10).

Abstract: A process for recycling plastic waste in a steam cracker, wherein a melt obtained from plastic waste is converted into products at from 400.degree. 550.degree. C., and a distillate fraction is separated off from the products at from 180.degree. to 280.degree. C. and is fed as feed material to a steam cracker.

Abstract: A catalyst for use in a process for steam conversion of a heavy hydrocarbon feedstock includes the steps of: providing a heavy hydrocarbon feedstock; providing a catalytically active phase comprising a first metal and a second metal wherein said first metal is a non-noble Group VIII metal and said second metal is an alkali metal; and contacting said feedstock with steam at a pressure of less than or equal to about 300 psig in the presence of said catalytically active phase so as to provide a hydrocarbon product having a reduced boiling point. The catalyst may be supported on a support material or mixed directly with the feedstock and comprises a first metal selected from the group consisting of non-noble Group VIII metals and mixtures thereof and a second metal comprising an alkali metal wherein said catalyst is active to convert said heavy hydrocarbon at a pressure of less than or equal to about 300 psig.

Abstract: A self-sustaining system and process for converting organic waste feedstreams into usable solid and gas end products includes a plurality of interconnected retorts, an apparatus for flash pyrolyzing the feedstream to form intermediate gas and solid products, a means for introducing a water spray to refine and cool the intermediate products, a means for separating the gas product from the solid product and a means for regenerating, and thereby further refining, the solid product. In a self-sustaining process, wastes which would otherwise be landfilled are converted to an activated carbon product and a combustible gas mixture of hydrogen, carbon monoxide, and lower hydrocarbons.

Abstract: In a process for thermally cracking a low-quality feed stock containing a considerable proportion of heavy fractions such as high-boiling fractions, and evaporation residual oil, and a system used therefor, in which the low-quality feed stock is withdrawn from the preheater of the thermal cracking furnace to separate and remove a required proportion of said heavy fractions and thereafter returned to subject the feed stock to further preheating and thermal cracking. The low-quality feed stock thermally cracked has a predetermined proportion of the heavy fractions removed, and coking in the thermal cracking system at various lines is avoided from occurring.

Abstract: This invention relates to a process for upgrading a hydrocarbonaceous material to a product having a lower boiling point than the initial boiling point of said hydrocarbonaceous material and/or a higher boiling point than the final boiling point of said hydrocarbonaceous material, the process comprising heating a feed composition comprising said hydrocarbonaceous material in an enclosed space in the absence of externally supplied water or hydrogen at a temperature in the range of about 750.degree. F. to about 1300.degree. F. and a pressure sufficient to maintain the specific gravity of the contents of said enclosed space in the range of about 0.05 to about 1.5 for an effective period of time to yield said product, said feed composition being characterized by the absence of aromatic compounds with boiling points at atmospheric pressure below about 350.degree. F.

Abstract: Apparatus and method for initiating pyrolysis of a feedstock by establishing a continuous, standing shock wave. Several embodiments of a shock wave reactor (10, 100, 150) are disclosed; each is connected to receive an ethane feedstock and a carrier fluid comprising superheated steam. The feedstock and the carrier fluid are pressurized so that they expand into parallel supersonic streams that mix due to turbulence within a mixing section (36) of a longitudinally extending channel (12) of the shock wave reactor. The carrier fluid heats the ethane feedstock as it mixes with it, producing a mixture that flows at supersonic velocity longitudinally down the channel. A gate valve (44) disposed downstream of the channel provides a controlled back pressure that affects the position of the shock wave and the residence time for the reaction. The shock wave rapidly heats the mixture above a pyrolysis temperature, producing a desired product by cracking the feedstock.

Abstract: A liquid tin-containing antifoulant composition is injected into a metal-walled thermal cracking reactor tube, concurrently with the injection of a gaseous stream (preferably a steam-diluted C.sub.2 -C.sub.4 alkane stream), through a nozzle of an injection quill which is positioned in the center region of the reactor tube substantially parallel to the flow of the gaseous stream.A liquid tin-containing antifoulant is injected into a metal-walled thermal cracking reactor tube through a nozzle of an injection quill at a temperature of about 1000.degree.-1300.degree. F. while a gaseous stream (preferably a steam-diluted C.sub.2 -C.sub.4 alkane stream) flows through the reactor tube, followed by raising the temperature to about 1400.degree.-1800.degree. F. Preferably, the metal walls of the reactor tube are treated with steam after the antifoulant injection at about 1000.degree.-1300.degree. F. but before the antifoulant injection at about 1400.degree.-1800.degree. F.

Abstract: An improved process for vaporizing a crude petroleum feedstock, preferably one boiling in the vacuum gas oil range or higher, prior to thermal cracking to olefins, wherein such feedstock is preheated, in one or more stages, in the convection section of a tubular steam cracking furnace, characterized by conducting the preheating in the presence of a small amount of hydrogen, preferably at a hydrogen/feed ratio of from about 0.01 to about 0.15 wt. %, so as to inhibit coke formation.

Abstract: An installation for steam cracking hydrocarbons comprises at least one hydrocarbon cracking furnace, an indirect quench heat exchanger for the effluents leaving the furnace, direct quench means for said effluent, and means (36, 38) for injecting erosive solid particles into the installation for decoking purposes. The installation also includes a cyclone (10) placed at the outlet from the indirect quench heat exchanger to separate the solid particles from the gaseous effluent, with the solid particle outlet (14) from said cyclone being connected to storage tanks (20, 30) connected in series with isolating valves (16, 28, 34), a source (38) of gas under pressure being provided to raise the pressure in one of the tanks and to inject the solid particles into the installation.

Abstract: The present invention provides a method and an apparatus for pyrolytically cracking a hydrocarbon vapor feedstock. The hydrocarbon vapor feedstock is contacted with water prior to cracking. While the hydrocarbon vapor feedstock is being contacted with water, both the feedstock and the water are heated by indirect heat exchange with at least one process stream containing waste heat. Consequently, a portion of the water vaporizes and combines with the hydrocarbon vapor feedstock. The hydrocarbon vapor feedstock is subsequently cracked in the presence of the vaporized water.

Abstract: Apparatus and process for compressing and quenching a cracked gas stream from a hydrocarbon cracking furnace including the step of feeding furnace output directly into an ejector in the effluent line, the ejector acting to quench and compress the effluent by injection of pressurized motive fluid into the ejector thereby rapidly mixing the motive fluid with the effluent for quick quenching and compression to prevent coke build-up and allow efficient heat exchanger and low pressure furnace operation.

Abstract: The present invention relates to a process and an apparatus for steam cracking a mixture of hydrocarbons comprising passing steam and the mixture of hydrocarbons through at least one heated cracking tube. The process is characterised in that it is controlled by analyzing the mixture of hydrocarbons fed to the cracking tube with an infrared spectrophotometer to determine the absorbances at a number n of wavelengths in the range 0.8 to 2.6 microns and by using the results of this absorbance to determine one or more values V of steam cracking process conditions which will achieve a desired value P of the space time yield of one or more products of the steam cracking reaction.

Abstract: The invention is directed to steam-cracking in a fluid bed reaction zone, of a charge of hydrocarbons having at least two carbon atoms per molecule.In this process the charge (3) circulates with steam (2) and inert solid particles, heated at a temperature T.sub.1 from 500.degree. to 1,800.degree. C., through at least one enclosure (7). A gas effluent is separated from the particles in the enclosure and fed to a quenching zone (8) opening into said enclosure. Said effluent is circulated with cooling second solid particles which are at a temperature T.sub.2 lower than T.sub.1 and at most equal to 800.degree. C. A steam-cracking effluent is then recovered through line (15).This process can be used in petrochemistry, particularly for producing ethylene and propylene.

Abstract: Improved operation of the ACR process is achieved by regulating the reactions within a small area in the combustion feedstock mixing zone, "Scorch Zone", by the addition of steam or other fluid such as ethane at the point of feed injection.

Abstract: A process is disclosed for converting a gaseous or vaporized hydrocarbon feedstock to a product comprising ethylene, acetylene or a mixture thereof.

Abstract: This invention relates to a method for on-line decoking of flame-cracking reactors whereby decoking is achieved without interruption of the normal operation of such reactors and without the necessity to change feed equipment and/or disassemble reactor components. While maintaining the temperature of the effluent at 1000.degree. C. to 2000.degree. C., the flow of the hydrocarbon feedstock in the reactor is periodically stopped for a time sufficient to reduce the carbon deposits to an acceptable level.

Abstract: Coke and metals are removed from a carbo-metallic oil by contacting the carbo-metallic oil in a riser reaction zone with a relatively inert particulate sorbent material in the presence of steam and the resulting coked particulate sorbent material is regenerated in a regeneration zone in the presence of steam and oxygen to remove the carbonaceous deposits by means of oxidation, water gas reaction and carbon gasification. The operating conditions in the riser reaction zone and the regeneration zone are regulated to provide a maximum coke level on the regenerated particulate sorbent of about 0.25 wt. %.

Abstract: The invention relates to a process for operation of a plant for the cracking of hydrocarbons. In this process, the hydrocarbons in the cracking furnaces are indirectly heated by the heat incurred in the combustion of a heating medium with an oxygen containing gas. In order to reduce operating costs of such a process, it is suggested to mix the waste gas of a gas turbine with air and to pass the gas mixture to the cacking furnace for combustion of the heating medium whereby an electric generator is powered by the gas turbine.

Abstract: When steam cracking hydrocarbons to lower olefins in a tubular fired furnace having a convection section for preheating hydrocarbon feed, feedstock flexibility to process light feeds is provided by cooling mixed feed of steam and hydrocarbon followed by reheating to the desired mixed feed temperature.

Abstract: The invention is a pyrolysis furnace for cracking heavy oils to olefins. The furnace includes a convection zone and a radiation zone. In parallel streams, the heavy stream and a stream diluent are heated in the convection zone to the point of partial thermal cracking while in the other stream a lighter oil and steam are cracked to produce olefins. The hot, olefinic light stream is then mixed with the heated heavy stream and further cracked in the radiation zone.

Abstract: Crude oils are normally so viscous that they cannot be pumped through pipelines without periodic heating. The usual practice is to pump the oil from one heat station to another, with part of the crude oil being used to generate heat. This problem is solved by reducing the viscosity of the crude oil. The viscosity reduction is effected using reactors for partially cracking crude oil, mixing the partially cracked oil with incoming crude oil, separating gases from the liquid in the mixture in a flash vessel, condensing the gases to yield liquid hydrocarbons, and mixing the latter with untreated crude oil and liquid residue from the flash vessel to yield a flowable, relatively low viscosity mixture. Coke produced in the reactors is periodically reacted with superheated steam to yield hydrogen, which is used to improve the quality of some of the residue from the flash residue. The thus treated flash vessel residue is used to feed the reactors.

Abstract: A hydrocarbon converter furnace has an upper convection heating zone and a lower radiant heating zone, and tubing extends in those zones to convey a fluid hydrocarbon feed and steam in sequence through the convection and radiant heating zones. The tubing includes a feed section and branches therefrom in the radiant section of the furnace, the feed section and branches arranged so that the hydrocarbon and steam flow from the feed section to said branches; also provided is valving for controlling the relative rates of flow in the branches to reduce differential coking in the branches.

Abstract: An improvement in the conversion of high boiling liquid organic materials to low boiling materials, and more particularly, in the process of converting heavy hydrocarbon oil feedstocks to fuel range liquids is described. In its broadest aspects, the invention comprises a process for converting high boiling hydrocarbons to lower boiling materials characterized by an increase in aromatic content and a lower pour point which comprises contacting said high boiling hydrocarbons with water at a temperature of from about 600.degree. F. to about 875.degree. F. at a pressure of at least about 2000 psi in the absence of any externally supplied catalysts, and wherein the weight ratio of water to high boiling hydrocarbons is from about 0.5:1 to about 1:1, and the water and high boiling hydrocarbon form a substantially single phase system under the elevated temperature and pressure conditions utilized.

Abstract: The steam and thermal cracking of hydrocarbons is facilely carried out by in situ generating a stream of hot combustion gases including steam, advantageously in the configuration of a downstream axially extending, axially symmetrical helical flowstream, by combustion of steam-producing reactants in a combustion first reaction zone, and serially directly contacting and intimately admixing a liquid hydrocarbon feedstock with said gas of combustion in a downstream isodistribution, non-multi-tubular second reaction zone, advantageously first at a zone of reduced pressure thereof, the momentum of said gas of combustion at the point of direct contact being such as to provide all of the thermal and mechanical energy and heat transfer required to autogenously vaporize, entrain and effect cracking therein of said liquid hydrocarbon feedstock.

Abstract: A majority amount of a heavy hydrocarbon crude is reacted with a minor amount of brine, at supercritical temperature and pressure for the brine, for a predetermined period of time in order to upgrade and convert the heavy hydrocarbon crude into a lighter hydrocarbon crude of higher API gravity. The upgrading and conversion of a viscous heavy hydrocarbonaceous crude oil into lighter hydrocarbons is accomplished in a continuous reactor system and may be accomplished in a subterranean petroleum reservoir at supercritical temperature and pressure. The overall heat of reaction is neutral, i.e., neither exothermic nor endothermic. In order to provide the necessary temperature, heat is added to the system prior to the reaction. For an in situ application, a combustion operation may be utilized to provide the necessary temperature, and is initiated using an oxidizing gas injected through an injection well.

Abstract: The invention describes a process for producing light products, such as engine and diesel fuels, and fuel oils for conventional use by thermal conversion of heavy metal- and sulfur-rich-crude oil residues. Thermal cracking of the residues is done by mild cracking in several stages, where the residue remaining after separation of the conversion products of the preceding stage is fed to the respective subsequent stage.

Abstract: The invention relates to an improved hydrocarbon steam-cracking method intended to produce more particularly ethylene and propylene.The method is based on the utilization of a multi-channel system made of ceramic material, in which the charge and heat exchange fluids or refrigerants alternatively pass through the channels or rows of channels constituting the continuous assembly comprising a pyrolysis zone followed by a quenching zone.The method according to the invention is applicable to charges ranging from ethane to vacuum gas oils.

Abstract: Disclosed is a process for the thermal cracking of heavy oils, which comprises a thermal cracking step of contacting a heavy oil with a fine powder of a porous material fluidized by a fluidizing gas to mainly obtain a light oil and a regenerating step of gasifying and removing coke adhering to the fine powder taken out from the thermal cracking step while fluidizing the fine powder by a molecular oxygen-containing gas and a steam-containing gas, the fine powder being circulated between the two steps, wherein fine spherical particles having a pore volume of 0.2 to 1.5 cm.sup.3 /g, a specific surface area of 5 to 1500 m.sup.2 /g, an average pore size of 10 to 10,000 .ANG. and a weight average size of 0.025 to 0.25 mm, in which these properties are stably maintained at the temperature adopted for the thermal cracking, are used as the fine powder, and a hydrogen gas is made present at the thermal cracking step, the partial pressure of hydrogen is maintained at about 0.5 to about 5 Kg/cm.sup.

Abstract: A process for converting a heavy hydrocarbon into a more valuable product which comprises:adding to the heavy hydrocarbon at least two kinds of substances comprising an oil-soluble or water-soluble transition metal compound and an ultra-fine powder which can be suspended in a hydrocarbon and has an average particle size within the range from 5 to 1000 m.mu.;thermally cracking the heavy hydrocarbon in the presence of a hydrogen gas or a hydrogen sulfide-containing hydrogen gas; andrecovering the resulting lighter hydrocarbon oil.

Abstract: A process for producing improved yields of aromatics (benzene, toluene, xylene) by initially partially thermally cracking heavy hydrocarbon and thermally cracking ethane to high conversion and then completely cracking the partially cracked heavy hydrocarbon with the completely cracked ethane.

Abstract: A process is disclosed for the thermal cracking of heavy oil containing nonvaporizable, high-molecular weight hydrocarbone in the presence of steam in one or more thermal cracking tubes or ducts, which process is characterized in that a fluid comprising steam and heavy oil is flowed through a thermal cracking tube such that thermal cracking is carried out under the following conditions:(a) temperature of the fluid in the thermal cracking tube: 800.degree. to 1100.degree. C.(b) pressure of the fluid in the thermal cracking tube: 0 to 50 kg/cm.sup.2 G(c) flow rate or velocity of fluid through the thermal cracking tube: 10 to 100 m/sec, and(d) residence time of the fluid in the thermal cracking tube: at least 0.2 seconds.

Abstract: For parallel heat exchangers, one using a more preferred heat exchange medium as a heat exchange source and another using a less preferred heat exchange medium, maximum use of the more preferred heat exchange medium is used prior to use of the less preferred heat exchange medium in achieving a desired total heat exchange through the parallel heat exchange system. In employing such a heat exchange system in a cracking process it is combined with individual control of flows of feed fluid and diluent fluid to a plurality of individual cracking tubes in a cracking furnace to maintain a desired mass flow of feed fluid and ratio of mass diluent fluid to steam fluid to each such cracking tube.

Abstract: A process for the selective production of petrochemical products by thermal cracking is disclosed. The process includes feeding methanol to a thermal cracking atmosphere of hydrocarbons in such a way that the ratio, as carbon atoms, of methanol and at least one starting hydrocarbon is at least 0.05:1, thermally cracking the at least one starting hydrocarbon at a cracking temperature of from 650.degree. to 1300.degree. C., and quenching the resulting reaction product.

Abstract: A method of controlling temperature during a pyrolysis reaction wherein the predominant pyrolysis reactions are endothermic. A fuel and oxidizer are combusted in a combustion zone to produce a hot gas stream at a superatmospheric pressure. The hot gas stream is then passed through a converging-diverging nozzle to accelerate the hot gas stream to a velocity of at least about mach 2. The reactant to be pyrolyzed is injected into the supersonic hot gas stream to produce a reaction mixture flowing at supersonic velocity and initiate the endothermic pyrolysis reactions. Substantially immediately thereafter the velocity of the reaction mixture is reduced over a predetermined reaction time to convert the kinetic energy of the reaction mixture to thermal energy in an amount sufficient to substantially offset the endothermic reactions taking place while maintaining supersonic flow. At the end of the predetermined reaction time the velocity of the reaction mixture is reduced to subsonic flow and the reaction quenched.

Abstract: The method and apparatus are used to disperse a liquid component throughout a gaseous component and to supply a uniform mixture of components to a heat exchanger in a process for thermal cracking hydrocarbons. The method for supplying the mixture of components from a nonuniform mixture includes several supply steps. First, the nonuniform mixture is separated into liquid and gaseous components. Then, the flow of gaseous component is accelerated to a high velocity. Next, the liquid component is dispersed through the gaseous component in a region of its high velocity flow to obtain a uniform mixture. Finally, the uniform mixture is supplied to the heat exchanger through an outlet conduit.The method is preferably accomplished with an assembly that is fabricated from a number of components. An inlet conduit supplies the gaseous component to a venturi which accelerates the flow velocity of the gaseous component in the assembly. A liquid supply conduit provides the liquid component to an atomizer in the assembly.

Abstract: An extraction residue obtained by solvent deasphalting of a residual oil is mixed with a carrier gas and thermally cracked at a temperature of 400.degree. C. to 600.degree. C. in a tube-type cracking apparatus to obtain cracked oil and pitch. The use of the carrier gas, which may be either an inert gas such as nitrogen or a reactive gas such as hydrogen, permits a flow velocity through the cracking apparatus sufficient to substantially prevent coking. Preferably, the cracking conditions are controlled so that the yield of cracked oil is not more than about 30 to 35%.

Abstract: The formation of carbon on metals exposed to hydrocarbons in a thermal cracking process is reduced by contacting such metals with an antifoulant selected from the group consisting of a combination of gallium and tin and a combination of gallium and antimony.

Abstract: A process for selectively producing olefins and aromatic hydrocarbons by thermal cracking of hydrocarbons which comprises the steps of: burning hydrocarbons with oxygen in the presence of steam to produce a hot gas of from 1300.degree. to 3000.degree. C. comprising steam; feeding a heavy hydrocarbon to the hot gas to thermally crack the heavy hydrocarbon under conditions of a temperature not lower than 1000.degree. C., a pressure not higher than 100 kg/cm.sup.2 g, and a residence time of from 5 to 20 milliseconds; further feeding a light hydrocarbon downstream of the feed of the heavy hydrocarbon in such a way that a light hydrocarbon with a lower boiling point is fed at a lower temperature side downstream of the feed of the heavy hydrocarbon, thereby thermally cracking the light hydrocarbon under conditions of a reactor outlet temperature at not lower than 650.degree. C., a pressure at not higher than 100 kg/cm.sup.

Abstract: Combustion air for steam cracking furnaces is preheated by indirect heat exchange with medium pressure and low pressure steam that has been expanded through steam turbines from high pressure steam produced in the hot section of an ethylene production plant.

Abstract: A process and system for the production of olefins from heavy hydrocarbon feedstocks. A heavy hydrocarbon feed is first pretreated at high pressure and moderate temperatures to preferentially remove coke precursors in a liquid product. The pretreated hydrocarbon is then separated into lighter and heavier fractions; the lighter fraction being further thermally cracked to produce olefins.

Abstract: A thermal cracking process for producing petrochemical products from hydrocarbons which comprises the steps of: burning hydrocarbons with oxygen in the presence of steam to produce a hot gas of from 1300.degree. to 3000.degree. C. comprising steam; feeding a mixture of methane and hydrogen to the hot gas in such a way that a methane/hydrogen molar ratio is over 0.05; further feeding starting hydrocarbons to the hot gas comprising the methane, hydrogen and steam so that the starting hydrocarbons containing hydrocarbon components of higher boiling points are, respectively, fed to higher temperature zones; subjecting the starting hydrocarbons to thermal cracking while keeping the cracking temperature at 650.degree. to 1500.degree. C., the total residence time at 5 to 1000 milliseconds, the pressure at 2 to 100 bars, and the partial pressure of hydrogen, after thermal cracking of a hydrocarbon comprising hydrocarbon components whose boiling point exceeds 200.degree. C., at least 0.

Abstract: In methods of manufacturing olefines by thermally cracking hydrocarbons, there is disclosed a thermal cracking method for producing olefines from hydrocarbons, characterized in that hydrocarbon in burnt with oxygen in the presence of steam to generate a high-temperature gas containing steam of 1500.degree.-3000.degree. C., methane and hydrogen are supplied into the high-temperature gas containing said steam, with the molar ratio of methane to hydrogen in said high temperature gas being 0.05 or more, then hydrocarbon to be cracked is supplied into said high-temperature gas containing said methane, hydrogen and steam, so that the hydrocarbon is subjected to thermal cracking by maintaining the partial pressure of hydrogen at more than at least 0.1 bar at the outlet of a reactor, under conditions of reaction temperature, 800.degree.-1200.degree. C. and residence time in the reactor 5-300 milli second, and then the reaction product is cooled in a rapid manner.

Abstract: A thermal cracking process for producing olefins from hydrocarbons which comprises the steps of burning hydrocarbons with less than the theoretical amount of oxygen in the presence of steam to give a hot gas of from 1400.degree. to 300.degree. C. comprising steam and hydrogen prior to reaction; feeding to the hot gas comprising the steam and hydrogen, a mixture of methane and hydrogen so that a methane/hydrogen molar ratio in said hot gas is over 0.05; further feeding a starting hydrocarbon to the hot gas mixture comprising the methane, hydrogen and steam; subjecting the starting hydrocarbon to thermal cracking while keeping the partial pressure of hydrogen at least 0.1 bar at the outlet of a reactor, the temperature at 800.degree. to 1200.degree. C., and the residence time at 5 to 300 milliseconds; and quenching the resulting reaction product.

Abstract: A thermal cracking process for selectively producing petrochemical products from hydrocarbons which comprises the steps of: burning hydrocarbons with oxygen in the presence of steam to produce a hot gas of from 1300.degree. to 3000.degree. C. comprising steam; feeding hydrogen to the hot gas; further feeding starting hydrocarbons to the hot gas comprising the steam and hydrogen so that the starting hydrocarbons containing hydrocarbon components of higher boiling points are, respectively, fed to higher temperature zones so as to thermally crack the respective hydrocarbons under different conditions while keeping the cracking temperature at 650.degree. to 1500.degree. C., the total residence time at 5 to 1000 milliseconds, the pressure at 2 to 100 bars, and the partial pressure of hydrogen, after thermal cracking of a hydrocarbon comprising hydrocarbon components whose boiling point exceeds 200.degree. C., at least 0.1 bar; and quenching the resulting reaction product.

Abstract: Fouling of tubes carrying refinery and petrochemical process streams, especially at high operating temperatures, is reduced by introducing aluminum stearate or aluminum acetate into the stream.