The invention relates to a utility fluid, such as a fluid containing aromatic and non-aromatic ringed molecules, useful as a diluent when hydroprocessing pyrolysis tar, such as steam cracker tar. The specified utility fluid comprises ≧10.0 wt % aromatic and non-aromatic ring compounds and each of the following: (a) ≧1.0 wt % of 1.0 ring class compounds; (b) ≧5.0 wt % of 1.5 ring class compounds; (c) ≧5.0 wt % of 2.0 ring class compounds; and (d) ≦0.1 wt % of 5.0 ring class compounds. The invention also relates to methods for producing such a utility fluid and to processes for hydroprocessing pyrolysis tar.

In the hydroconversion processes of heavy hydrocarbon oils, in which the hydrogen is introduced at the reactor base by bubbling, the low diffusion rate of hydrogen, from the gas phase to the reaction liquid, limits the degree of conversion. The process circumvents the obstacle of the limited amount of reactant hydrogen by using a slurry bubble column reactor which reduces the formation of light hydrocarbon products, and therefore the hydrogen required for the hydroconversion, allowing to operate at full conversion.

The invention relates to a method to start up a Fischer-Tropsch process. A catalyst with a latent activity is used. The catalyst comprises titania, cobalt, promoter, and chlorine. The catalyst comprises more than 0.7 and less than 4 weight percent of the element chlorine, calculated on the total weight of the catalyst.

A coke catching apparatus for use in hydrocarbon cracking to assist in the removal of coke and the prevention of coke build up in high coking hydrocarbon processing units. The apparatus includes a grid device for preventing large pieces of coke from entering the outlet of the process refining equipment while allowing small pieces of coke to pass through and be disposed of. The coke catching apparatus can be easily disassembled to be removed from the refining process equipment and cleaned.

Recovering hydrocarbons from oil shale can include injecting a heated working fluid into a first vessel containing particulate oil shale in a pyrolysis mode. The heated working fluid can have a temperature above a production temperature to pyrolyze kerogen in a stationary bed of the oil shale at or above the production temperature. An effluent can concurrently flow out of the first vessel to be injected into a second vessel in preheating mode. The second vessel containing particulate oil shale has an average temperature below the production temperature so as to capture heat from the effluent sufficient to increase the average temperature of the particulate oil shale and to condense condensable hydrocarbon product while also removing entrained mineral fines mists of condensed hydrocarbons from the effluent. Liquid hydrocarbons can concurrently be collected from the first vessel and/or the second vessel.

A method is described for shutting down a Fischer-Tropsch reactor fed with a reactant gas mixture comprising a synthesis gas and a recycle gas recovered from the Fischer-Tropsch reactor in a synthesis loop, said Fischer-Tropsch reactor containing a Fischer-Tropsch catalyst cooled indirectly by a coolant under pressure, comprising the steps of: (a) depressurising the coolant to cool the reactant gas mixture to quench Fischer-Tropsch reactions taking place in the Fischer-Tropsch reactor, (b) stopping the synthesis gas feed to the Fischer-Tropsch reactor, and (c) maintaining circulation of the recycle gas through the Fischer-Tropsch reactor during steps (a) and (b) to remove heat from the Fischer-Tropsch reactor. The method safely facilitates a more rapid return to operating conditions than a full shut-down.

A process for shutting down a hydroprocessing reactor and for removing catalyst from the reactor, wherein the reactor includes a quench gas distribution system. The process comprises shutting off hydrocarbon feed to the reactor, stripping hydrocarbons from the catalyst, and cooling the reactor to a first threshold reactor temperature in the range of from 375-425° F. (190-218° C.). At least a portion of circulating gaseous medium flowing to the reactor is then routed through a temporary heat exchanger and cooling the gas to not less than 40° F. (4° C.). Once cooled, mixing the cooled gas with the circulating gaseous medium flowing to the reactor. Continuing steps routing and cooling until a second threshold temperature is reached wherein the reactor temperature is in a range between 120° F. and 250° F. (49° C.-121° C.). The reactor can then be purged with N.sub.2 gas, followed by introducing water into the reactor via the quench gas distribution system. The catalyst can then be safely removed from the reactor.

Systems and methods are provided for performing ethane steam cracking at elevated coil inlet pressures and/or elevated coil outlet pressures in small diameter furnace coils. Instead of performing steam cracking of ethane at a coil outlet pressure of ˜22 psig or less (˜150 kPa-g or less), the steam cracking of ethane can be performed in small diameter furnace coils at a coil outlet pressure of 30 psig to 75 psig (˜200 kPa-g to ˜520 kPa-g), or 40 psig to 75 psig (˜270 kPa-g to ˜520 kPa-g). In order to achieve such higher coil outlet pressures, a correspondingly higher coil inlet pressure can also be used, such as a pressure of 45 psig (˜310 kPa-g) or more, or 50 psig (˜340 kPa-g) or more.

Systems and methods are provided for performing the initial heating phase for a thick wall reactor, such as a hydroprocessing reactor, by using heat tracing to heat the exterior walls of the reactor. Instead of attempting to initially heat the reactor by passing a low pressure heat transfer gas through the interior of the reactor, external heater(s) placed under the reactor insulation can be used to heat the exterior of the reactor. An example of a suitable external heater is a heat tracing blanket, where heat is provided by passing steam through pipes in contact with the external surface or by electrical heaters in contact with the external surface. This can allow for more rapid heating of the reactor, so that a target temperature can be achieved in a time of 5.0 hours or less.

A coke catching apparatus for use in hydrocarbon cracking to assist in the removal of coke and the prevention of coke build up in high coking hydrocarbon processing units. The apparatus includes a grid device for preventing large pieces of coke from entering the outlet of the process refining equipment while allowing small pieces of coke to pass through and be disposed of The coke catching apparatus can be easily disassembled to be removed from the refining process equipment and cleaned.