JPH0421601B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is disclosed in US Pat.
No. 4,061,562 and No. 4,097,363, the disclosures of which are hereby incorporated by reference. More particularly, the present invention provides an improved fuel gas generation system for solid state heating in a TRC apparatus and method.

[Prior Art] The method to which the present invention relates will be specifically described in the environment of a conventional regenerative pyrolysis reactor (TRC) illustrated in FIG.

Referring to FIG. 1, in a prior art TRC process and system, the pyrolysis feedstock or resid enters through each line 10 with or without blending distillate heavy gas and the hydrogen It passes via line 12 to hydrogen desulfurization zone 14 . The hydrogen sulfide effluent gas enters the flash chamber 18 through line 16, from which hydrogen and contaminated gases (light gases) containing hydrogen sulfide and ammonia are removed overhead through line 20.
Meanwhile, flash liquid is removed through line 22. The flash liquid passes through a preheater 24;
It mixes with dilution vapor entering through line 26 and then flows through line 30 to the bottom of pyrolysis reactor 28.

A stream of hot regenerated solids is charged through line 32 and mixed with steam or other fluidizing gas entering through line 34 before entering riser 28 . The oil, water vapor and hot solids are entrained and flow upwardly through riser 28 and exit through curved segment 36 at the top of the riser to induce centrifugation of the solids from the exiting stream. The stream containing the majority of solids passes through an ascending discharge section 38 and can, if desired, mix with finished solids entering through line 40 either before or after proceeding to solids separation-stripper 42. A separate stream containing the majority of decomposition products is discharged axially through conduit 44 and may be cooled by means of a quench stream entering through line 46 before solids separator-stripper 48. can.

Stripper steam is charged to solids separators 42 and 48 through lines 50 and 52, respectively. Product streams are removed from solids separators 42 and 48 through lines 54 and 56, respectively, and are combined in line 58 and passed to a secondary quench and product recovery system (not shown). Coke-laden solids are removed from solids separators 42 and 48 via lines 60 and 62, respectively, and are combined in line 64 leading to the coke burner. If desired, torch oil is added to line 6 while stripping steam is added via line 70 to strip the combustion gases from the heated solids.
8 to the burner 66. Air can be added to the burner through line 69. Combustion gases are removed from the burner through line 72 for passage to a heat and energy recovery system (not shown), while regenerated hot solids, relatively coke-free, are passed through line 72 for circulation to riser 28. 32 and removed from the burner. To produce cracked products containing ethylene and molecular hydrogen, the petroleum residue is passed through a catalytic hydrodesulfurization zone at temperatures between 343 and 482°C in the presence of hydrogen, and hydrogen is combined with the oil during the hydrogen cycle stage. The hydrodesulfurized residual oil, with entrained inert thermal solids and diluent gas that acts as a heat source,
It passes through a pyrolysis zone at a temperature of 1372° C. with a residence time of about 0.05 to 2 seconds, producing decomposition products and ethylene and hydrogen. For the production of ethylene by pyrolysis, a hydrogen feedstock, i.e. a hydrocarbon feedstock, at least 90% of which by volume comprises a light gas oil of crude oil boiling at temperatures between 204 and 343°C, is used as a diluent gas and an entrained inert heating gas. From about 705 to
Pass through the pyrolysis zone at a temperature of 1372°C with a residence time of about 0.05 to 2 seconds. The weight ratio of oil gas to fuel oil is at least 0.3, but at the same time the severity of cracking is such that the product immediately reaches 705 °C when leaving the cracking zone, corresponding to a methane yield of at least 12% by weight based on the feed oil. Quenching at a lower temperature can ensure that the ethylene yield is greater than the methane yield on a weight basis.

[Problems to be Solved by the Invention] In such prior art TRC systems, coke adhering to granular solids is gasified and discarded. An object of the present invention is to provide a method for effectively utilizing such discarded coke to improve overall efficiency.

Furthermore, in the TRC system as described above, a relatively large coke burner is required to remove coke. SUMMARY OF THE INVENTION An object of the present invention is to provide a method that makes effective use of coke and can process the coke using a device that is relatively smaller than conventional devices.

[Means for Solving the Problem] According to the invention, this object is achieved by providing a temperature in the cracking zone in the range of 705 to 1372°C, in which the hydrocarbon feedstock or hydrodesulfurized residue entrains the inert solids. In the TRC process, which passes through a cracking zone with a residence time of 0.05 to 2 seconds with a diluent gas, the step of removing coke deposited on the solids consists of: a) supplying fuel, air and steam to the combustion vessel to remove H ₂ O; generating a fuel gas containing water vapor in which the molar ratio of H ₂ is greater than or equal to that necessary to decompose the water vapor by reaction with carbon in the presence of hydrogen; b supplying the fuel gas containing water vapor to a tubular transfer line; c feeding the granular solids on which coke has been deposited into the tubular transfer line; d mixing the fuel gas containing water vapor with the granular solids; and e adhering to the granular solids by heat and water vapor in the tubular transfer line. This is accomplished by a pyrolysis fuel gas generation method that converts coke into fuel gas.

[Effect of the invention] According to the pyrolysis fuel gas generation method of the present invention,
In the TRC method, not only the coke deposited on the solid is effectively removed, but also effective fuel gas can be obtained by generating additional fuel gas using the coke removed in the removal process. , the efficiency of the whole device can be increased.

Furthermore, since the reaction takes place in the tubular transfer line, the coke removal is rapid and the size of the coke removal equipment can be significantly reduced.

[Example] Figure 2 shows a method used in one embodiment of the present invention.
1, a TRC system is shown in which a device according to the invention is used in place of the coke burner 66 in the prior art TRC system shown in FIG.

Particulate solids and hydrocarbon feed gas for the TRC process cracking reaction enters tubular reactor 13A through lines 11A and 12A. Tubular reactor 1
The products of pyrolysis in 3A are separated from particulate solids in separator 14A and sent to line 15A where they are cooled by quenching material injected from line 17A. The particulate solids separated from the product in separator 14A are sent through line 16A to solids stripper 22A. line 15A
Residual particulate solids contained in the product sent to is separated from the quench gas in a second separator 18A and sent to a solids stripper 22A. Product gas free of particulate solids is removed from the top of the second separator 18A through line 19A.

The granular solids fed into the solid stripper 22A are intended to provide heat during the pyrolysis in the tubular reactor 13A, but the granular solids will adhere to the granular solids if they are to be reused for successive cracking steps. The coke produced must be removed and returned to the tubular reactor 13A, reheated so as to provide the required temperature.

Preferably, the particulate solids are degassed by steam supplied to solid stripper 22A through line 23A before being reheated. The particulate solids stripped of gaseous impurities in solid stripper 22A are at a temperature of about 788°C.

In the present invention, preheating devices 32A, 34A, and 36A are provided for the combustion vessel 30A and the fuel, air (or oxygen), and steam supplied thereto, and a fuel gas containing steam at a temperature of about 1260° C. is generated. Ru.

Furthermore, in the present invention, the transfer line 44A
A fuel gas and water vapor generated by combustion in the combustion vessel 30A and granular solids from which gas impurities have been removed in the solid stripper 22A are supplied thereinto, where they are mixed and the granular solids are heated. At the same time, decoking is performed. Transfer line 44A has a length to provide sufficient residence time for reaction with steam supplied from combustion vessel 30A, thereby causing pyrolysis by reaction of coke with carbon in the presence of hydrogen. The coke is converted into fuel gas and removed from the particulate solids. In the preferred embodiment, transfer line 44A
The length is approximately 33 meters. If necessary, air can also be supplied as a carrier gas from line 26A.

Fuel gas supplied from combustion vessel 30A at a temperature of 1260°C is mixed in transfer line 44A with particulate solids supplied from solid stripper 22A at a temperature of approximately 788°C, and the particulate solids and fuel gas are rapidly 971
The equilibrium temperature of °C is reached. During passage through transfer line 44A, the mixture of fuel gas, steam, and particulate solids is provided with the heat necessary for the coke cracking reaction. As a result, the mixture was cooled by about 17°C to about 954°C.
℃ and sent out from the transfer line 44A.

In this decomposition reaction, the mixture of fuel gas and water vapor supplied from the combustion vessel 30A is converted into H ₂ O
The molar ratio of H ₂ O to H 2 is chosen to be above the ratio required for water vapor to decompose by reacting with carbon in the presence of hydrogen, in which case H ₂ O to H ₂
The molar ratio of is equal to or higher than the equimolar ratio. By setting such a ratio, the coke attached to the granular solids is completely removed by a thermal decomposition reaction and converted into fuel gas.

A separator 46A, such as a cyclone separator, is provided to separate the heated decoked particulate solids from the fuel gas, and the particulate solids separated in separator 46A are passed through line 48A to a temperature of approximately 954°C.
It is returned to the thermal solid container 27A at a temperature of , and is again supplied to the tubular reactor 13A. Meanwhile, the separated fuel gas is taken out through line 50A at a temperature of about 954°C and utilized.

In another method embodiment of the present invention illustrated in FIG. 3, only fuel and air are sent to combustion vessel 30A and combusted at a temperature of about 1260° C. to provide fuel gas. Fuel gas at 1260°C and particulate solids at about 788°C are mixed in transfer line 44A and brought to a temperature of about 808°C. Air is then routed through line 54A to transfer line 44A. The fuel gas in transfer line 44A is combusted to raise the temperature of the particulate solids to approximately 954°C.
to rise to. The resulting flue gas is separated from the particulate solids being heated in separator 46A and discharged through line 52A. The heated particulate solids are returned to the system to provide the heat of reaction. In the figure, 38A indicates the fuel supply, and 40A indicates the air supply.

An example of the system and method shown in FIG. 3 is as follows. : 3150Kg of fuel per hour in preheater 32A
13MM preheated to 333℃ and heated to 556℃
SCFD air is heated to 1260°C in combustion vessel 30A to produce 15.6MM SCFD fuel gas.

15MM SCFD 1260°C fuel gas from solid stripper 22A in transfer line 44A per hour.
Mix with 0.45MMKg of stripped granular solids. The granular solid has carbon deposited on it at a rate of 720Kg/hour. The synthesized fuel gas-particulate solid mixture reaches an equilibrium temperature of 805 DEG C. at 14.6 kg/cm2 within about 5 milliseconds. then 13MM
Send SCFD air to transfer line 44A,
The fuel gas of 15.6MM SCFD is combusted with air to raise the temperature of the granular solid to 954℃, and 720 kg of carbon deposited in the granular solid is combusted per hour.

The combusted gases from transfer line 44A are separated from particulate solids in separator 46A and discharged as flue gas.

Although preferred embodiments of the present invention have been described above, those skilled in the art will be able to envision many modifications and variations based on the basic concept of the invention. Therefore, the technical scope of the present invention should be limited only by the claims.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a TRC system and process according to the prior art. FIG. 2 is a schematic diagram of the fuel gas generation system and process of the present invention. FIG. 3 shows an alternative embodiment in which the fuel gas is burned as a flue gas to provide additional heat to the particulate solids.

Claims (1)

[Claims] 1. The temperature in the cracking zone is in the range of 705 to 1372°C, where the hydrocarbon feedstock or hydrodesulfurized residue is reacted with entrained inert solids and diluent gas.
Passes through the decomposition zone with a residence time of 0.05 to 2 seconds
In the TRC process, the step of removing coke deposited on solids consists of a) supplying fuel, air and steam to a combustion vessel so that the molar ratio of H ₂ O to H ₂ is increased by reaction with carbon in the presence of hydrogen; generating a fuel gas containing water vapor in a proportion greater than or equal to that necessary to decompose the water vapor; b supplying the fuel gas containing water vapor to a tubular transfer line; c supplying granular solids on which coke has been deposited to the tubular transfer line; Pyrolysis fuel gas generation characterized by: d) mixing a fuel gas containing water vapor with granular solids, and e converting coke attached to the granular solids into fuel gas by heat and steam in a tubular transfer line. Method. 2 Particulate solids pass through the tubular transfer line approximately 33
A method according to claim 1, wherein the decoking is carried out by passing the fuel gas containing water vapor at a feed rate of m/s, and the decoking reaction with said water vapor lowers the temperature of the particulate solids and the fuel gas. .