Abstract: A system for co-processing crude oil with residuum includes an ebullated bed hydrocracking unit; an atmospheric distillation column fluidly coupled to the ebullated bed hydrocracking unit; a vacuum distillation column fluidly coupled to the atmospheric distillation column and the ebullated bed hydrocracking unit; and a deasphalting unit fluidly coupled to the vacuum distillation column and the ebullated bed hydrocracking unit; and a control system communicably coupled to the ebullated bed hydrocracking unit, the atmospheric distillation column, the vacuum distillation column, and the deasphalting unit. The control system is configured to perform operations including operating the deasphalting unit to produce a first cut that includes deasphalting oil, a second cut that includes resin oil, and a third cut that includes asphaltene.

Abstract: Oxygen is removed from a gas feed such as a landfill gas, a digester gas or an industrial CO2 off-gas by removing sulfur-containing compounds and siloxanes from the feed gas, heating the feed gas, injecting one or more reactants for oxygen conversion into the heated feed gas, carrying out a selective catalytic oxygen conversion in at least onesuitable reactor and cleaning the resulting oxygen-depleted gas. The reactants to be injected comprise one or more of H2, CO, ammonia, urea, methanol, ethanol and dimethylether (DME).

Abstract: A fuel tank system is disclosed that includes a fuel tank and a first fluid flow path between a gas space in the fuel tank and outside of the fuel system. A gas separation membrane is disposed with a first side in communication with the first fluid flow path and a second side in communication with a second fluid flow path. A fluid control device is in communication with the second fluid flow path and is configured to provide fluid flow from the second fluid flow path to a liquid space in the fuel tank or to outside of the fuel system. A prime mover is disposed in communication with the second fluid flow path, and is configured to move fluid on the second fluid flow path from the second side of the separation membrane to the fuel tank liquid space or to outside of the fuel system.

Abstract: An apparatus for efficiently removing the exuded substance and/or the attached substance on the surface of a catalyst (catalyst surface substance) from the catalyst is provided. The apparatus comprising a main body, the apparatus for removing a catalyst surface substance present on a surface of a catalyst from the catalyst by bringing a gas flow into contact with the catalyst housed in the main body, wherein a gas flow length in a flow direction of the gas flow is 55 mm or more, and an average flow velocity of the gas flow is 80 m/s or more and 500 m/s or less in terms of a linear velocity at 15° C. and 1 atm.

Abstract: Systems and methods for the external processing flash zone gas oil by recycling it through a vacuum residuum hydroprocessing unit before reentering the delayed coking process.

Abstract: Apparatuses and methods are disclosed for contacting radially flowing fluids with solid particles (e.g., catalyst) with reduced tendency for fluidization of the particles, and especially a sealing portion of the particles at the top of a particle retention zone disposed between screens at upstream and downstream positions relative to radial fluid flow. Fluidization is reduced or eliminated by offsetting openings of the screens in the axial direction, such that upstream openings in the upstream screen are above highest downstream openings in a downstream stream. The offset in openings imparts a downward flow component to radially flowing fluid, thereby reducing solid particle fluidization without the need to induce a specific pressure drop profile along the entire axial direction of the screens.

Abstract: This invention describes a two-stage regeneration zone that has a regenerated catalyst circuit such as the one that results from the mixing of a partially regenerated catalyst with a residual coke rate of between 0.3 and 0.7% and a totally regenerated catalyst with a coke rate that is less than 0.15%. All things being equal, this double-population regenerated catalyst enables the maximization of the LCO yield.

Abstract: Process for the preparation of C3 and C4 olefins and gasoline by: (a) contacting in a fluidised bed reactor a light hydrocarbon feedstock with a first catalyst inventory comprising a medium pore size zeolite catalyst, wherein the first catalyst inventory is a fresh catalyst inventory; (b) combining at least part of the catalyst inventory as used in step (a) with one or more catalyst streams to form a second catalyst inventory comprising a medium pore size zeolite catalyst and a large pore size zeolite catalyst; (c) contacting a hydrocarbon feedstock with the second catalyst inventory in a reactor riser to form cracked products.

Abstract: An addition apparatus, a fluid catalytic cracking (FCC) system having an addition apparatus, and a method for adding material to an FCC unit are provided. In one embodiment, an addition system having the capability of interfacing with a material container is provided that allows the addition system to obtain information relating material held in the container. In one embodiment, at least some of the information is contained on a tag affixed to the container. Other information may be retrieved and/or sent to the addition system controller from a remote data source, such as a catalyst supplier.

Abstract: The present invention relates generally to catalysts and, in particular, relates to in-situ replacement of catalyst within a reactor. In an embodiment, the present invention comprises a method for the in-situ replacement of catalyst bodies in a catalytic reactor comprising removing catalyst bodies in-situ from at least one modularized section of a catalytic layer within a catalytic reactor and replacing the removed catalyst bodies in-situ with replacement bodies comprising catalytic function wherein at least 10% of the total catalyst bodies within the layer are replaced.

Abstract: A method for adding material to an FCC unit is provided. In one embodiment, a method for adding material to an FCC unit includes providing a first vessel under low pressure containing a first material, moving the material through a first eductor to the FCC unit, and determining an amount of material moved dispensed from the vessel through the eductor.

Abstract: A fines injection apparatus, a fluid catalytic cracking (FCC) system having a fines injection apparatus, and a method for using the same are provided. In one embodiment, a FCC system includes a FCC unit, a fines collector, and a fines injector coupled to the fines collector for retuning the fines recovered in the fines collector to the FCC unit. In another embodiment, an apparatus for injecting fines into a FCC system includes a fines separator coupled to an effluent stream and an injection apparatus coupled to a regenerator. A conduit is provided for delivering collected fines from the fines separator to the injection apparatus. In yet another embodiment, a method for injecting fines into FCC system includes collecting fines from a waste stream of a FCC system, automatically transferring the collected fines to a fines injection apparatus, and periodically injecting the transferred fines into the FCC system.

Abstract: An addition apparatus, a fluid catalytic cracking (FCC) system having an addition apparatus, and a method for adding material to an FCC unit are provided. In one embodiment, an addition system for an FCC unit includes a container, a first eductor and a sensor. The eductor is coupled to an outlet of the container. The sensor is configured to detect a metric of material dispensed from the container through the eductor. A valve is provided for controlling the flow through the eductor. A controller provides a control signal for regulating an operational state of the valve. In another embodiment, an FCC system having an addition system is provided. In yet another embodiment, a method for adding material to an FCC unit is provided.

Abstract: Method of metering at least one solid, particulate catalyst into a reactor containing a fluidized bed (11) of particles in an at least partly gaseous medium, in which the catalyst is metered discontinuously at prescribed time intervals into the fluidized bed (11) at at least one metering point (10). According to the present invention, a fluid stream is firstly introduced into the reactor (5) so that a region having a reduced particle density is formed in the fluidized bed (11) around the metering point (10) and the catalyst is subsequently metered into this region. As a result of the prior introduction of a fluid stream (“preblowing”) before the actual introduction of the catalyst, the catalyst can penetrate significantly deeper into the fluidized bed from the metering point due to the reduced particle density and is dispersed better.

Abstract: A mobile fluid cracking catalyst injection system and a method of controlling a fluid catalyst cracking process is provided. In one embodiment, a mobile fluid catalyst cracking system includes a transportable platform, a catalyst reservoir coupled to the platform and a flow control device coupled to an outlet of the reservoir and adapted to control the flow of catalyst from the reservoir to a fluid catalyst cracking unit (FCCU).

Abstract: One exemplary embodiment can include a method of controlling a catalyst transfer vessel cycle of loading and unloading based on an expected level of a catalyst in a downstream vessel for a hydrocarbon conversion unit. The method can include calculating an expected catalyst level in the downstream vessel based on the unloading of the catalyst transfer vessel to adjust a setpoint to change the catalyst transfer vessel cycle of loading and unloading.

Abstract: The invention relates to the partial recovery of discarded, spent, or waste fluid catalytic cracking (FCC) equilibrium catalyst by use of a separation device located off site, away from any FCC Process unit or Petroleum Refining area, whereby the separation of recoverable material is achieved by means of both magnetic properties exhibited from contaminated metals deposited on individual catalyst particles and inertial or momentum contributions based on size and density of each individual catalyst particle. The invention provides a process to recover twenty to forty percent of the original discarded, spent, or waste FCC equilibrium catalyst for reuse.

Abstract: A fluidized-bed reactor is disclosed. The fluidized-bed reactor steadies the gas flow through the fluidized bed chamber of the reactor. The swirl chamber of the reactor consists of a conical housing in which a conical insert is also situated. This creates an annular gap between the housing and the insert, which acts as the swirl chamber and which, according to the geometry of the two components, causes a velocity of the gas flow which remains the same along the height, which increases or which decreases. Such a reactor can also be called a constant annular-gap reactor.

Abstract: The invention is a catalyst injection system and method for injecting catalyst. In one embodiment, a fluid catalytic injection system includes vessel configured to store one or more catalysts, a pressure transmitter, a pressure control valve, a discharge valve, and a controller. The pressure control valve is coupled to the vessel and regulates the gas pressure therein. The discharge valve is coupled to the vessel and controls a discharge of catalyst from the vessel. The pressure transmitter provides a metric of pressure to the controller as an input. The controller contains instructions, that when executed, prevents the simultaneous opening of the pressure control valve and the discharge valve. In another embodiment, a method for injecting catalyst into a fluid catalytic cracking unit is provided. The method includes regulating pressure within a catalyst storage vessel, changing an amount of catalyst in the storage vessel, and preventing a simultaneous occurrence of the regulating and changing steps.

Abstract: This invention provides processes for maintaining a desired particle size distribution in an oxygenate to olefin reaction system. In one embodiment, the invention comprises replacing lost catalyst fines with less active co-catalyst particles. By adding less active co-catalyst particles to the reaction system, desirable fluidization characteristics and hydrodynamics can be maintained without affecting the overall (or primary catalyst) performance and product selectivities. The invention is also directed to a population of catalyst particles having a desirable particle size distribution well-suited for realizing ideal fluidization and hydrodynamic characteristics.

Abstract: Disclosed is an apparatus and process for controlling space velocity in a fluidized catalytic conversion reactor. The catalyst flux rate can be adjusted during the process of the reaction to adjust the space velocity and maintain a fast fluidized flow regime therein. The set parameter in the reactor may be pressure drop which is proportional to catalyst density.

Abstract: A defined catalyst withdrawal and replacement program for optimizing the productivity and the economics of catalyst consumption in a multi-reactor system is disclosed. Catalyst cost is reduced by minimizing removal of the newest catalyst and maximizing removal of older catalyst to achieve an overall reduction of catalyst age in the multi-reactor system.

Abstract: A method and system for recovering fines from a light FCC-type effluent gas. Cracked gases from the reactor are cooled by direct contact with circulating oil in an oil quench tower. The circulating oil also washes out the catalyst fines carried with the reactor effluent gas. A flow of the oil from the quench tower bottoms is sent through one of a pair of filters to remove fines and recycled to the tower. The other filter is in backwash operation using a compressed gas to remove the fines therefrom and into a surge drum. Fuel oil or quench oil is added to the drum to form a slurry, which carries the catalyst fines to the regenerator where the oil is combusted to supply the FCC system heat requirements. Since a minimum amount of fuel oil is generated in the FCC, fuel oil is imported to inventory the quench tower.

Abstract: A defined catalyst withdrawal and replacement program for optimizing the productivity and the economics of catalyst consumption in a multi-reactor system is disclosed. Catalyst cost is reduced by minimizing removal of the newest catalyst and maximizing removal of older catalyst to achieve an overall reduction of catalyst age in the multi-reactor system.

Abstract: The operation of fluid catalytic converter (FCC) units can be stabilized through use of tests wherein a first catalyst and a second catalyst are introduced into the FCC unit in at least two different ratios, at two different times, in order to establish the effect of these catalyst ratios on a given operating parameter. This information is used to establish a unit response curve (or unit response envelope) for the catalyst ratios versus the operating parameter. This unit response curve (or envelope) is thereafter used to control the operation of the FCC unit.

Abstract: Injection of particulate materials into industrial processes can be improved through use of a vessel mounted on a weighing device and which is vented through use of two separate and distinct valves. Optionally, a predetermined pressure in the vessel is maintained through use of a pressure transmitter and an on/off mode of operation.

Abstract: A process and apparatus for contacting reactants with a particulate catalyst while indirectly contacting the reactants with a heat exchange medium performs heat exchange in a first reaction zone and moves catalyst, at least intermittently, through the second reaction zone while the process is operating. The first reaction zone is preferably a fixed bed reaction zone. The use of first reaction zone as a fixed bed reaction zone simplifies the process arrangement by not requiring means for catalyst movement in a reaction zone that performs simultaneous heat exchange. Long periods of operation are possible since the first reaction zone will typically experience a slow rate of catalyst deactivation and need infrequent regeneration. The first reaction zone may also be designed for catalyst movement, but independently controlled from the first reaction zone to facilitate the movement of catalyst therethrough.

Abstract: A process for converting a heavy hydrocarbon fraction comprises a step a) for treating a hydrocarbon feed in a hydroconversion section in the presence of hydrogen, the section comprising at least one three-phase reactor containing at least one ebullated bed of hydroconversion catalyst operating in riser mode for liquid and for gas, said reactor comprising at least one means for extracting used catalyst from said reactor and at least one means for adding fresh catalyst to said reactor, b) a step for treating fresh catalyst and conditioning the catalyst using a process leading to a gain in the activity of the catalyst during treatment of the feed in said conversion reactor. This process for conditioning the catalyst before adding it to the reactor can comprise a step for impregnating the catalyst with a chemical substance, or a complete sulphurisation step, or a step for adding an additive mixed with the fresh catalyst which is added.

Abstract: A process for use of magnetic separation to remove non-magnetic particles from FCC catalyst is disclosed. A stream of circulating catalyst from a fluidized catalytic cracking (FCC) unit is charged to a magnetic separator. The catalyst is magnetically fractionated into at least three fractions, a high-metals fraction which is discarded, an intermediate-metals content fraction which is directly recycled to the FCC unit, and an inert, relatively magnetic metals-free fraction which is also discarded. Preferably, the high-metals fraction is immediately mixed with the inert, low-metals fraction, and the combined high-metals/inert fraction is pneumatically transmitted together to a spent catalyst storage facility for disposal.

Abstract: A process and arrangement for contacting a moving bed of compact particulate material, usually catalyst, with a radial flow of fluid maintains an unconfined surface of catalyst particles in place by passing fluid axially into the upper surface of the bed and maintaining radial gas flow across an inlet screen at an elevation that is above the upper most elevation of perforations for withdrawing gas flow from the particulate bed. Two vertical screens confine the bed of catalyst. Perforations cover substantially the entire length of the inlet screen. The outlet portion of the screen has perforations that end below the top of the free surface of the catalyst bed and define an upper bed portion therebetween. The inlet screen directs gas flow radially across the inlet screen into an upper portion of the bed and cause at least partial axial flow of gas through the upper portion of the particle bed.

Abstract: This process controls the magnetic separation of high metals catalyst by influencing the magnetic susceptibility by carbon levels on catalyst. In an FCC/RCC.RTM. operation employing magnetic separation of catalyst, particularly where the catalyst has enough metals to exhibit a high magnetic susceptibility, e.g., 110.times.10.sup.-6 emu/g or higher, all of the catalyst may be attracted to the magnet and go to the magnetic reject side. By controlling the amount of carbon, coke, or graphite present on the catalyst after partial regeneration, the magnetic properties of the catalyst can be diminished and separation can occur. Varying the amount of carbon affects the magnetic metals, the higher the magnetic susceptibility, and yet the catalyst particles will have a lower carbon level. The lower the magnetic susceptibility, the less metals, the higher the activity, and the higher the coke/carbon content.

Abstract: The catalyst inside a catalytic reaction column is replaced while running the catalytic reaction by diverting a basically monophase fluid to keep it from passing through the catalyst, evacuating from the column the catalyst that has lost at least a portion of its properties, introducing into the column a quantity of catalyst that is approximately equal to the quantity of catalyst that was evacuated from the column, and restoring the circulation of the basically monophase fluid through the catalyst.

Abstract: A process and apparatus for incorporating additives into a circulating inventory of equilibrium catalyst in a fluid catalyst cracking (FCC) unit are disclosed. Hot regenerated catalyst is removed from the FCC regenerator, cooled, optionally subjected to magnetic catalyst separation, and at least a portion of the cooled catalyst is contacted with a solution of an additive material without forming a separated liquid phase. Additive treated catalyst is recycled to the FCC unit, preferably directly into the regenerator.

Abstract: A process for contacting reactants with a particulate catalyst while indirectly contacting the reactants with a heat exchange medium amid simultaneous exchange of catalyst particles by an operation that sequentially restricts reactant flow while moving catalyst through reaction stacks in which the reactant flow has been restricted. The process permits a change out of catalyst in a channel type reactor arrangement that would normally restrict catalyst flow during operation. Moving catalyst through a heat exchange type reactor having reactant and heat exchange channels permits control of catalyst activity as well as temperatures.

Abstract: A method for replacing particles in a process that transfers particles is disclosed. This invention employs a seal zone which is in communication with two zones of the process and in which particles that are being added to the process are purged. This invention allows particles to be replaced without reducing the normal rate of particle transfer through the process, which results in a savings in downtime costs. This invention is adaptable to a multitude of processes for the catalytic conversion of hydrocarbons in which deactivated catalyst particles are regenerated.

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: A vessel arrangement and process for contacting a fluid reactant with a particulate catalyst in a plurality of flow channels and discharging fluid and particles from the flow channels. The particles are discharged axially from the bottom of the flow channels into an unconfined bed of particles. Fluid is discharged in a transverse direction through the sides of the flow channels and across screen openings located a short distance above the channel outlets. A plurality of chambers, additional particulate material or baffles regulate fluid flow through sections of the screens and prevent excessive fluid velocity in any section from holding up particle flow through the flow channels. The reactor arrangement and process of this invention is a particularly useful for arrangements that may be used to operate a reactor under isothermal or other controlled temperature conditions where a heat transfer fluid surrounds a plurality of tubular conduits or multiple flow channels that confine the particles and fluid.

Abstract: Bastnaesite and magnesium-containing materials can be chemically reacted by use of reactions wherein alumina is made into a sol by use of a mono-protonic acid and then reacted with a magnesium-containing ingredient (e.g., magnesium acetate) and a bastnaesite ingredient such that, upon spray drying and calcination of the resulting composition, the bastnaesite is chemically reacted with magnesia to form a bastnaesite/magnesia/alumina compound having SO.sub.x activity.

Abstract: This FCC process suspends a layer of catalyst in a riser proximate or above the riser outlets. The density at the riser outlets is higher than the flowing density in the riser. The suspended catalyst provides a disengagement zone that enhances the separation of catalyst from product vapors. The riser operates in a manner that prevents any discharge of catalyst from its end. The arrangement also provides a convenient method for vetoing stripping vapors into a closed reactor cyclone system.

Abstract: This invention makes possible substantially continuous flow of uniformly distributed hydrogen and hydrocarbon liquid across a densely packed catalyst bed to fill substantially the entire volume of a reactor vessel by introducing the fluids as alternate annular rings of gas and liquid (i.e. a mixture of liquid hydrocarbon and a hydrogen-containing gas) at a rate insufficient to levitate or ebullate the catalyst bed. Catalyst are selected by density, shape and size at a design feed rate of liquids and gas to prevent ebullation of the packed bed at the design feed rates. The liquid and gas components of the hydrocarbon feed flow into the catalyst bed from concentric annular rings that are coaxial with the catalyst bed. At the desired hydrocarbon flow rate, such catalyst bed continually flows in a plug-like manner downwardly through the reactor vessel. Catalyst is removed on a periodic or semicontinuous basis by laminarly flowing catalyst particles in a liquid stream out of the bottom of the catalyst bed.

Abstract: A method and apparatus for replacing particles in a process that transfers particles is disclosed. This invention employs a seal zone which is in communication with two zones of the process and in which particles that are being added to the process are purged. This invention allows particles to be replaced without reducing the normal rate of particle transfer through the process, which results in a savings in downtime costs. This invention is adaptable to a multitude of processes for the catalytic conversion of hydrocarbons in which deactivated catalyst particles are regenerated.

Abstract: A reactor arrangement and process for contacting a fluid reactant with a particulate catalyst in a plurality of flow channels and discharging converted reactant fluid and particles from the flow channels. The particles are discharged axially from the bottom of the flow channels into an unconfined bed of particles. Reactants are discharged in a transverse direction through the sides of the flow channels and across screen openings located a short distance above the channel outlets. A plurality of chambers regulate fluid flow through sections of the screens and prevent excessive fluid velocity in any section from holding up particle flow through the flow channels. The reactor arrangement and process of this invention is particularly useful for arrangements that may be used to operate a reactor under isothermal or other controlled temperature controlled conditions where a heat transfer fluid surrounds a plurality of tubular conduits or multiple flow channels that confine the particles and reactants.

Abstract: An improved catalytic process for heavy hydrocarbon conversion (usually but not necessarily in the presence of nickel and vanadium in the feedstock and on the catalyst) to produce lighter and selective molecular weight fractions. This process is specifically targeted as a means of retaining specialty high-valued, preferably microspherical additives (SHVA) which assist in attaining preferred conversion products such as gasoline, especially the recent gasolines meeting compositional requirements of "Reformulated Fuel".Selective magnetic retention of these high-cost specialty additives can be achieved by incorporating into them selective magnetic moieties, preferably manganese, the heavy rare earths and superparamagnetic iron. Selective retention is achieved by passing spent or regenerated catalyst containing small amounts of these SHVAs through a magnetic separator, and selectively recycling them back to the circulating catalyst.

Abstract: A process for the fluid catalytic cracking of heavy fraction oils containing heavy metals such as Ni and V, which comprises withdrawing a portion of ferrite-containing catalyst particles circulating in a fluid catalytic cracking apparatus, separating the thus withdrawn catalyst particles into metals-richly deposited catalyst particles and metals-poorly deposited ones by using a magnetic separator and then returning the metals-poorly deposited catalyst particles, together with fresh ferrite-containing catalyst particles, into said cracking apparatus.

Abstract: A process for the simultaneous replacement of a first catalyst by a second catalyst which first catalyst is circulating as a moving bed of solid particles in a hydrocarbon treating unit, which unit comprises at least one processing reactor. The first catalyst is withdrawn downstream of the reactor, or of each reactor, in the direction of catalyst circulation. The second catalyst is simultaneously injected upstream of the reactor or of each reactor. The bulk density of the material withdrawn downstream of the reactor, or of each reactor, is measured continuously. The withdrawal of the first catalyst and the injection of the second catalyst into the reactor concerned are interrupted when the bulk density so measured is equal to that of the second catalyst.

Abstract: In an ebullated bed process for hydrotreating a distillate hydrocarbon feedstock it has been found that a catalyst addition slurry is made up with catalyst and feedstock. A control system provides for a constant distillate feedstock rate during intermittent catalyst addition.

Abstract: The disclosed method and apparatus provides for providing addition of micro-spheroidal ("MS") Fluid Catalytic Cracking ("FCC") catalyst additives and/or bulk catalyst to an in situ circulating, active catalyst inventory of a fluid catalytic cracking unit at times and rates precisely controlled to sustain an effective additive concentration. In a preferred version of this invention, each of a series of such apparatus comprising one such device for each catalyst additive, is operated on a basic cycle time length during a portion of which the unit is engaged in active addition while in the remainder of the time it is passive.

Abstract: This invention relates to an improved catalytic process for carrying out heavy hydrocarbon conversion, usually, but not necessarily, in the presence of nickel and vanadium on the catalyst and in the feedstock, by catalytic cracking gas oils and heavy carbometallic oils to lighter molecular weight fractions. The process is facilitated by the continuous addition of one or more heavy rare earth additives, including gadolinum, terbium, dysprosium, holmium, erbium, and thulium, all having exceptionally high paramagnetic properties, which as they accumulate on aged catalyst, are used to achieve enhanced magnetic separation of aged catalyst. These additives are unusual in that they not only act dramatically as magnetic hooks to assist in removing old, nickel and vanadium poisoned catalyst, but also act to achieve increased activity and improve selectivity of the remaining catalyst, and of equal importance, tend to resist catalyst deactivation.

Abstract: In a steam generator for recovering heat in a hot fluidized bed of solid particles, wherein coils of the steam generator make a 180.degree. U-bend, the U-bend portion of the coils are protected from overheating by installing an open top insulating box around the U-bend portion of the coil. In use solid particles from the circulating fluidized bed accumulate in the insulating box thus providing a non-moving layer of solid particles surrounding the U-bend which thermally insulates the U-bend portion of the coil from the higher temperature encountered in the moving fluidized bed.

Abstract: By continuously or intermittently adding amounts of magnetically active moieties, e.g. iron compounds, over time so that the moiety deposits on a catalyst or sorbent in a fluid catalytic cracker or similar circulating hydrocarbon conversion unit, older catalyst, being more magnetic, can be readily separated from catalyst which has been in the system a shorter time. Separation is readily accomplished by passing the catalyst and/or sorbent through a magnetic field and discarding the more magnetic 50% by wt. or more preferably 20% by wt., while recycling the remainder back to the hydrocarbon conversion unit.