JPS6323237B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improved integrated fluid coking and coke gasification process for producing unsaturated light hydrocarbons and aromatics useful as chemicals and chemical intermediates.

Fluid coking for producing fuels such as gas oil and naphtha is a well known process. Integrated fluid coking and coke gasification processes are also known.

Fluid coking methods for producing chemicals and chemical intermediates are also known.
Therefore, generally speaking, when it is desired to produce a chemical rather than a fuel oil, fluid coking processes usually include a high temperature transfer line coking zone and a fluidized bed coking zone.

Additionally, a small amount of hot solids may be added to the gas-solid separation zone, such as in a cyclone separator used to separate entrained solids from the vaporous coking furnace product, to prevent coke buildup on the walls of the cyclone separator. It is also known to introduce

Thus, in the present invention, the carbonaceous material is coked in a conventional fluid coking zone and the resulting vaporized product is then transferred to a conventional fluid coking zone used to remove entrained solids from the coke oven vaporized product. It has been found that coking of chemicals and chemical intermediates production can be accomplished by heating coke oven vapor products in a gas-solid separation zone to temperatures sufficient to decompose them into unsaturated hydrocarbons. Heat in the gas-solid separation zone is provided by sending a portion of the hot solids from the gasification zone to the gas-solid separation zone.

In accordance with the present invention, (a) a carbonaceous material having a Conradson residual carbon content of at least 10% by weight is reacted in a coking zone containing a bed of fluidized solids maintained at fluid coking conditions to convert the vaporous coking zone; (b) introducing at least a portion of the coked solids into a heating zone operated at a temperature higher than the coking zone temperature to form a coke product and coke deposited on the fluidized solids; (c) recycling a first portion of the heated solids from the heating zone to the coking zone, and heating the second portion of the heated solids to a temperature above the temperature of the heating zone; (d) into a fluidized bed gasification zone maintained at a temperature of
In an integrated coking gasification process consisting of steps in which the vaporous coking zone conversion product is sent to a gas-solid separation zone with entrained solids, a portion of the solids is withdrawn from the gasification zone and the gas-solid separation zone is introducing the portion of solids into the gas-solid separation zone in an amount sufficient to maintain a temperature within the range of about 1200 to about 1700°C, thereby discharging at least a portion of the vaporous coking zone product. An integrated coking gasification process is provided which features conversion to unsaturated hydrocarbons.

Illustrating the accompanying drawings, approximately 15% by weight of heavy residual oil having a boiling point (at atmospheric pressure) of approximately 1050㎓
A carbonaceous material having a Conradson residual carbon content of . The caulking zone 12 includes a solid body having an upper level indicated by the reference numeral 14, e.g.
A fluidized bed of coke particles (40-1000 microns) is maintained. Carbonaceous feedstocks suitable for this invention include heavy hydrocarbonaceous oils, heavy and vacuum distilled petroleum crude oils, petroleum atmospheric distillation residues, petroleum vacuum distillation residues, pitch, asphalt, bitumen, and other heavy Includes hydrocarbon residues, coal, coal slurries, liquid products derived from coal liquefaction processes and mixtures thereof. Typically, such feedstock is
Conradson carbon residue content of at least 10% by weight, typically from about 10 to about 50% by weight (for Conradson carbon residue content, see ASTM Test D-189-
65). A fluidizing gas, such as steam, is introduced into the bottom of the coking reactor 1 via line 16 in an amount sufficient to obtain a surface fluidizing gas velocity in the range of 0.5 to 5 ft/sec. At temperatures above the coking temperature, e.g., about 100 to about 400 degrees above the actual operating temperature of the coking zone, coke is introduced into the tube in sufficient quantities to maintain the coking temperature within the range of about 850 to about 1400 degrees. It is introduced into the reactor 1 via line 42. The pressure in the coking zone is approximately 5 to
It is maintained within the range of about 150 psig, preferably within the range of about 5 to about 45 psig. The lower part of the coking reactor serves as a stripping zone for removing occluded hydrocarbons from the coke. The coke stream is withdrawn from the stripping zone by line 18 and circulated to heater 2. The vaporous coking zone conversion product is passed through a gas-solid separation zone such as a cyclone 20 to remove entrained solids, and the removed solids are passed through a depletion zone 20 to remove entrained solids.
2 and then returned to the coking zone. The cyclone separator system may be one or more cyclones.
In accordance with the present invention, the temperature of the cyclone is adjusted to convert at least a portion of the coking zone conversion products to unsaturated low boiling hydrocarbons such as olefins and diolefins and to aromatics useful as chemicals or chemical intermediates. The temperature is maintained within the range of 1200-1700°, preferably about 1300-1500°. The temperature of the cyclone is also such that a sufficient amount of water is drawn from the gasifier by line 58 and then injected into the lean phase in the region near the cyclone entrance by line 60 above the dense fluidized bed. The elevated temperature is maintained by introducing a hot solids stream into the cyclone. The heated gasifier solids can be discharged through the cyclone inlet into the vaporized coke oven product entering the cyclone, or the hot gasifier solids can be introduced directly into the cyclone separator. . Preferably, the amount of hot gasifier solids introduced into the cyclone is
Such that at least 20% by weight of the coke oven vapor product is converted to unsaturated hydrocarbons having less than 6 carbon atoms. . The resulting vapor leaves the cyclone via line 24 and enters a scrubber 25 attached to the coking reactor.
If desired, the scrubber condensed heavy material stream can be recycled to the coking reactor via line 26. Additionally, if desired, a portion of the carbonaceous feed can be injected into the scrubber to provide adequate volume for conveying coke fines to the coking zone. The cyclone conversion product is withdrawn from the scrubber 25 via line 28 for rectification in a conventional manner. Heater 2
There, the stripped coke (commonly referred to as cold coke) from coking reactor 1 is introduced by line 18 into a fluidized bed of hot coke having an upper level indicated by reference numeral 30. The bed is heated in part by sending fuel gas to the heater via line 32. Supplementary heat is added to the heater by coke circulating in line 34. The gaseous effluent of the heater containing entrained solids enters a cyclone (which may be a first cyclone 36 and a second cyclone 38) where separation of large entrained solids occurs. The separated large solids are returned to the heater bed via their respective cyclone depletion. The heater gaseous effluent, which still contains entrained solids fines, is removed from the heater 2 via line 40.

Hot coke is removed from the fluidized bed of heater 2;
This is then circulated thereto by line 42 to supply heat to the coking reactor. Another portion of the coke is removed from the heater 2 and is sent by line 44 to the gasification zone 46 of the gasifier 3 where a fluidized coke bed having a level indicated by reference numeral 48 is maintained. It will be done. If desired, a purge stream of coke can be removed from heater 2 by line 50.

The gasification zone is at a temperature of about 1,500 to about 2,000 psig and a pressure of about 5 to about 150 psig, preferably about 10 to about
A pressure of 60 psig is maintained, more preferably a pressure of about 25 to about 45 psig. Steam via line 52 and oxygen-containing gas such as air, commercial oxygen or oxygen-enriched air via line 54 are sent to gasifier 3 via line 56. Reaction of the coke particles in the gasification zone with steam and oxygen-containing gas produces a fuel gas containing hydrogen and carbon monoxide. The gasifier product fuel gas (which may also contain some entrained solids) is removed as overhead from the gasifier 3 by line 32 and subjected to heat requirements as previously described. is introduced into the heater 2 to provide a portion of the

Although the process has been described in terms of circulating coke as the fluidizing medium for ease of description, the fluidized seed particles to which the coke is deposited may include silica, alumina, zirconia, magnesia, calcium oxide, alundum, mullite, bauxite. or the like. The fluidized solid may or may not be catalytic in nature.

[Brief explanation of the drawing]

The accompanying drawing is a schematic flowchart of one embodiment of the present invention, and the reference numerals indicating the main parts are as follows. 1: Reactor, 2: Heater, 3 Gasifier.

Claims (1)

Claims: 1. (a) A vaporous coking zone by reacting a carbonaceous material having a Conradson residual carbon content of at least 10% by weight in a coking zone containing a bed of fluidized solids maintained at fluid coking conditions. (b) introducing a portion of the coke-laden solids into a heating zone operated at a temperature higher than the coking zone temperature to form the solids; (c) recirculating a first portion of the heated solids from the heating zone to the coking zone, and heating the second portion of the heated solids to a temperature above the temperature of the heating zone; in an integrated coking-gasification process comprising the steps of: introducing the vaporous coking zone conversion product into a gas-solid separation zone with entrained solids; , withdrawing a portion of the solids from the gasification zone and introducing the portion of the solids into the gas-solid separation zone in an amount sufficient to maintain the gas-solid separation zone at a temperature within the range of about 1200 to about 1700°C. 1. An integrated coking-gasification process characterized in that the method comprises: introducing and thereby converting at least a portion of the vaporous coking zone product into unsaturated hydrocarbons. 2. The method of claim 1, comprising introducing a portion of the gasification zone solids into the vaporous coking zone product entering the gas-solid separation zone. 3. A method according to claim 1, comprising introducing a portion of the gasification zone solids directly into the gas-solid separation zone. 4. Conveying a portion of the solids from the gasification zone to the gas-solid separation zone in an amount sufficient to maintain the gas-solid separation zone at a temperature within the range of about 1300 to about 1500 degrees Celsius. The method described in Section 1. 5. The method of claim 1 comprising maintaining the coking zone at a temperature of about 850 to about 1400 °C. 6. The method of claim 1, comprising maintaining the gasification zone at a temperature of about 1500 to about 2000 °C. 7. The method of claim 1, comprising maintaining each of the coking zone and gasification zone at a pressure of about 5 to about 150 psig. 8 Coking zone at least 20% of vaporous product
2. The process of claim 1, wherein a sufficient amount of solids is introduced into the gas-solid separation zone to convert % by weight to unsaturated hydrocarbons having less than 6 carbon atoms. 9 reacting a second portion of heated solids from the heating zone with steam and an oxygen-containing gas in a gasification zone to produce a hot gaseous stream containing hydrogen and carbon monoxide; 2. A method as claimed in claim 1, comprising introducing the entrained solids into the heating zone.