JPS6129995B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydrocarbon thermal decomposition apparatus, and particularly to an apparatus suitable for decomposing hydrocarbon compounds such as ethylene.

When light hydrocarbon compounds such as naphtha and ethane are pyrolyzed to produce gases containing off-hrain, the pyrolysis furnaces used are tube-type crackers and A shell-and-tube heat exchanger is used as a heat exchanger to rapidly cool the generated gas. However, the adhesion of coke, carbon, and tar inside the pipe is unavoidable, and it is necessary to temporarily stop the operation of the equipment and perform a so-called decoking operation to remove the coke, carbon, and the like. Therefore, when pyrolyzing heavy oils such as crude oil and heavy oil, carbon, etc. are generated significantly, and in the case of the above-mentioned pipe type structure, the inside of the pipe is filled with carbon, etc. as soon as the pyrolysis operation starts. It becomes blocked and becomes unusable. Therefore, the cracking furnaces currently in use are moving bed or fluidized bed types that use a heat medium, and the gas produced by the cracking reaction is cooled by direct spraying of oil or water. A cooling method has been adopted in which air is sprayed on the surface of the air. However, with this cooling method using oil or water spray, it is impossible to recover the sensible heat of the cracked gas, and a large amount of cooling oil or water is required, which poses economical problems. There are many.

In view of the problems seen in the prior art as explained above, an object of the present invention is to avoid clogging caused by carbon etc. during thermal decomposition of hydrocarbons, and to avoid intermittent shutdown of equipment, etc. An object of the present invention is to provide a hydrocarbon pyrolysis device that can be used.

The present invention provides a fluidized bed type pyrolysis furnace that pyrolyzes hydrocarbons while forming a fluidized bed using a heat medium, and a fluidized bed pyrolysis furnace in which cracked gas exiting the pyrolysis furnace is introduced into the fluidized bed as a fluidizing gas, and the cracked gas is A fluidized bed heat medium regenerator that regenerates the fluidized bed heat medium by quenching the heat medium and separating the generated gas.A fluidized bed heat medium regenerator that regenerates the fluidized bed heat medium by combustion treatment of the heat medium particles, and the heat regenerated by the regenerator. a system for recirculating the medium to the fluidized bed quenching through the cooler; a system for supplying carbon-adhered heat medium particles produced in the pyrolysis furnace to the heat medium regenerator; and a system for recirculating the medium through the heat medium regenerator. The apparatus is characterized by comprising a system for recirculating the heated heat transfer medium particles to the pyrolysis furnace.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a system diagram of a hydrocarbon pyrolysis apparatus showing an embodiment of the present invention. In Fig. 1, the entire apparatus includes a pyrolysis furnace 1, a heat exchanger (quench cooler) 1
3, a heat medium regenerator 32, and a heat medium cooler 49, and all of these devices employ a fluidized bed. The heat exchanger 13 is arranged on the downstream side of the fluidized bed type pyrolysis furnace 1 , and is connected to the pyrolysis furnace 1 through a conduit 8 . A cracked raw material, for example, heavy oil such as crude oil or heavy oil, is passed through a conduit 3 and heated in a raw material preheater 4 . Although the type of preheater does not matter, it has a raw material heating coil 5. The heating raw material is passed through conduit 6
It is supplied to the decomposition furnace 1 via. In the thermal decomposition reaction, steam is added for the purpose of suppressing the production of carbon etc. and improving the yield of olefins. In this system, steam is supplied from the conduit 7 as a fluidizing medium and the steam is supplied from the heat medium regenerator 32. The delivered heat medium (high temperature heat medium particles) is fluidized to form a fluidized bed. The raw material is atomized by steam branched from the conduit 7 and injected into the fluidized bed, where it quickly contacts and mixes with the heating medium and the fluidizing steam, reaches a high temperature, and is decomposed into olefins and gasified. The generated gas is introduced into a heat exchanger 13 through a conduit 8 after collecting heat medium particles in a cyclone 2 provided in the reactor.

The heating medium in the reactor (cracking furnace) 1 is covered with carbon and tar produced as by-products during the reaction, and a certain amount is allowed to overflow from the overflow pipe 9, and while the flow rate is controlled by the valve 10, the lift gas is removed by the lift 11. 12, for example, by compressed air, to the regenerator 32. The lift air is separated from the heat medium by a cyclone 59, and only heat medium particles are supplied to the regenerator 32. The regenerator includes a blower 47
The air generated in the heat medium cooler 49 and the conduit 5
1, 54 and the startup heater 41, it is supplied from the conduit 43 to the regenerator 32, and uses this as a fluidization medium to fluidize the carbon adhesion medium, burn the adhering carbon, and heat the heat medium to a high temperature. . The regeneration medium is allowed to overflow in the overflow pipe 44 and is returned to the reactor 1 . At that time, in order to prevent the gas from the reactor from flowing toward the regenerator, the conduit 45
Supply steam from and seal the gas.

In the heat exchanger (quench cooler) 13, the cracked gas serves as a fluidizing gas to fluidize the heat medium (low temperature). The quencher 13 is provided with a coil 14 in a fluidized bed, and the kinetic heat of the decomposed gas is transferred to the cooling coil 14 via medium particles. Cooling coils are commonly used as boiler evaporator tubes. The main body shell of the rapid chiller 13 forms a membrane with the coil 15, and like the coil 14, it can be used as a boiler evaporation tube. The cracked gas at the outlet of the heat exchanger is cooled, passes through a conduit 19, collects particles in a cyclone 20, passes through a conduit 22, and is finally cooled in an oil spray cooler 23 with cooling oil supplied from a conduit 24. Gas and drain oil are separated in an oil separator 25, with the product gas being sent via conduit 26 to the refining section and the drain oil being sent via conduit 27 to the processing section.

The heating medium particles are sent from the hopper 57 provided in the cooler 49 to the supply hopper 17 of the quencher 13 by a transfer means 58, and are then sent to the quencher 13 through the conduit 16 while being controlled by a valve 18. .

The fluid medium of the quencher 13 is an overflow pipe 28.
It enters a regenerator 32 via a conduit 30, more quantitatively controlled by a valve 29. Quencher 1
Although the amount of heat transfer medium discharged from 3 is smaller than that of the cracking furnace, carbon and tar are still generated during the quenching process and adhere to particles, so they are burned in the regenerator 32. The heat medium of the regenerator 32 is cooled by a cooler 49, passes through a conduit 55 and a valve 56, and is stored in a storage tank hopper 57.

The combustion gas in the regenerator 32 passes through a conduit 33,
Particles are collected in cyclone 34 and enter waste heat recovery sections 36, 39 in conduit 35. The sections 36 and 39 each have a preheating boiler coil 3.
7 and 38 are provided. The waste gas is finally exhausted from the stack 40 to the atmosphere.

Combustion air is pressurized from the blower suction 46 to the blower 47, passes through the conduit 48 to the heat medium cooler 49, becomes preheated air in return for cooling the high temperature heat medium, and flows through the conduit 51, cyclone 52, and conduit 54. After that, it enters the startup heater 41. The startup superheater 41 generates high-temperature combustion gas using fuel supplied from the conduit 42 to raise the temperature of the regenerator during a cold start, and the temperature is raised to a temperature suitable for burning carbon, and the gas is supplied to the regenerator 32. Ru. During continuous operation, the temperature can be balanced by the combustion energy of carbon, so a superheater for startup is not required.

The temperature of the cracked gas generated in cracking furnace 1 is approximately 700℃.
~900°C, but is heat exchanged in the quench cooler 13 and cooled to 500~600°C, which is the reaction freezing temperature.

Figures 2a and 2b are an overall configuration diagram and a detailed diagram showing the main parts of the quencher (heat exchanger) 13 used in the present invention. Figure 2a is the structure of the fluidized bed quenching heat exchanger, and Figure 2b is the An explanatory diagram showing the structure of the heat exchanger tubes arranged in the fluidized bed, Figure 2c is a cross-sectional view of the heat exchanger tube with fins installed in the upper space of the fluidized bed, and Figure 2d shows the structure of the membrane wall (water cooling wall). It is an explanatory diagram. In each of the above figures, the cracked gas is introduced from the cracked gas inlet conduit 102 provided at the bottom of the heat exchanger main body 100, injected into the inlet cone 103, and further passed through the cracked gas dispersion 104 into the fluidized bed 133. evenly distributed. Heat carrier particles (for example, ceramic balls) sent from the hopper 127 are supplied into the fluidized bed 133, and at this time, they are fluidized by the action of the dispersed cracked gas to form the fluidized bed 133. In addition, under normal operating conditions, the fluidized bed 133:
A fluidized bed boundary is formed and stabilized up to the height at which the medium discharge conduit 131 is provided, and the cracked gas and heat medium particles are uniformly mixed within the fluidized bed. Further, within the fluidized bed 133, a heat exchanger tube coil 108 is arranged in a hairpin shape by being bent many times, and is suspended by headers 112 and 114. The heat exchanger tube 108 is also used as a heat exchanger tube of a boiler, and the boiler water is passed through the boiler water inlet conduit 1.
13 and exits through outlet conduit 115 to the steam canister.

The high-temperature sensible heat of the cracked gas is transferred to the heat medium, and due to the collision effect between the heat medium and the heat transfer tube 108,
Eventually, the decomposed gas is transferred to the boiler water flowing through the heat transfer coil 108, whereupon the decomposed gas is rapidly cooled and recovered as water vapor. Solid content such as carbon and tar generated during cooling is attached to the medium particles, and the medium particles are discharged from the medium discharge conduit 131 to the valve 13.
2 is extracted continuously by adjusting
It is discharged. After being discharged, the particles are sent to the regenerator 32 (FIG. 1), where they are combusted and the heat carrier particles are regenerated, as explained with reference to FIG. 1 above.

In the heat exchanger 100 described above, in order to simplify the structure and improve heat transfer efficiency, the heating coil 105 has a membrane wall (water-cooled wall) structure as shown in FIG. 117 and the boiler water outlet header 110. Boiler water is in boiler water inlet conduit 1
The point where the boiler water is introduced from the boiler water outlet and exits from the pipe 111 and sent to the steam can (not shown) is the boiler water heat transfer tube (heat transfer tube) 108 in the fluidized bed 133.
The same is true for . In the membrane wall (water-cooled wall) structure described above, a heat insulating material 106 is provided on the outside of the heat transfer tube 105 to further enhance the heat insulating effect. Furthermore, a wear-preventing heat-resistant material 107 is disposed inside the heating tube 105 to prevent wear (erosion) and corrosion caused by heat medium particles.

As mentioned above, the heat exchanger tubes 108 in the fluidized bed 133 have a hairpin structure bent many times, but the space 135 above the fluidized bed 133
In order to enhance the heat transfer effect, it is preferable to provide fins 109 as shown in the cross-sectional view of FIG. 2c.

The cracked gas is sent through a gas exhaust conduit 118 to a cyclone 119, where the heat carrier particles are collected and recovered. The decomposed exhaust gas is further sent to an oil separator 125 via a conduit 112, but on the way there, it is cooled by cooling oil supplied from a cooling oil conduit 123 in an oil cooler 124 having a bench lily structure. After being cooled in this way, the separated exhaust gas sent to the oil separator 125 contains drain oil 130 and produced gas 1.
26 and sent to the next processing step through respective routes.

On the other hand, the heat medium particles collected in the cyclone 119 are returned to the fluidized bed 133 through the heat medium recovery conduit 120 provided at the bottom thereof. At this time, it is preferable to introduce the sealing vapor 121 from a conduit or the like in order to prevent short circuit with the cracked gas.

Figures 3a and 3b show another embodiment of the quenching heat exchanger used in the present invention, and the main differences from the embodiment shown in Figure 2 are shown in Figure 2d. This is because the membrane wall (water-cooled wall) structure shown in 1 and the structure using a dispersion plate made of a perforated plate or the like are omitted. In other words, it adopts the spouted bed method, and the third
As is clear from Figure b, the heat exchanger tubes 208 are arranged horizontally, but the heat medium particle discharge conduit 13
1 and the medium discharge control valve 132 are similar to those of the previous embodiment. Further, for example, when the pyrolysis equipment is stopped, heat carrier particles enter the cracked gas inlet conduit 202.
To prevent this, an extraction pipe 220 and an extraction valve 221 are provided. The pyrolysis gas enters from the cracked gas inlet conduit 202 and is injected into the inlet cone 203 at a high pressure and at a high velocity, and the heat exchanger body is in the state shown by the arrows in FIGS. 3a and 3b. 100 flows inside. By performing such fluid movement,
The fluidized decomposition gas blows up heat carrier particles to form an upward flow in the central part and a downward reflux flow in the peripheral wall part, which is the upper part of the inlet cone 203 and the part where the heat exchanger tubes 208 are arranged horizontally. A fluidized bed 206 is formed.

The medium recovery cyclone 119 is connected to the heat exchanger main body 1
00, and the heat medium is collected and recovered, but the decomposed exhaust gas passes through the cyclone discharge pipe 122, the cooling gas discharge pipe 218, etc., and is sent to the oil cooler 124 as shown in FIG. 2a. Sent.

The above heat transfer tube (cooling coil) 208 is the second a
As in the case of FIGS. ) is connected. Furthermore, as already explained,
In this embodiment, the cyclone 119 is built into the heat exchanger body 100, and the manhole 219 is provided in the top cone of the body 100.

As mentioned above, the heat exchanger used in the present invention uses ceramic balls or the like as a heat medium, uses cracked gas as a fluidizing gas, forms a fluidized bed with the heat medium, and cools the cracked gas. As a structure,
In addition, during this cooling, heat transfer tubes are arranged in a hairpin shape in the fluidized bed to recover the sensible heat of the cracked gas through the above-mentioned medium particles, and the generated carbon, tar, etc. are attached to the medium particles. It is designed to be processed. Therefore, the decomposition gas can be cooled extremely effectively and economically, making it possible to carry out thermal decomposition reactions of not only light but also heavy hydrocarbon compounds with high efficiency. Furthermore, since it has become possible to recover the sensible heat of the decomposed gas, a significant effect can be obtained in terms of improving thermal efficiency. Furthermore, accidents such as tube blockage due to carbon, tar, etc. during pyrolysis have almost no longer been observed, and a significant improvement in pyrolysis efficiency has been observed in this aspect as well.

As described above, the present invention comprises a pyrolysis furnace, a heat exchanger (quench cooler), a regenerator, and a cooler all in a fluidized bed apparatus, and a heat medium circulation system and a regenerator By using a heat medium circulation system using a pyrolysis furnace, the heat medium can be repeatedly used, making it easy to recover sensible heat from the quench cooler.
In addition, the heat medium usage efficiency is high, and from a process economical point of view,
Extremely advantageous.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an embodiment of the hydrocarbon pyrolysis apparatus of the present invention, and FIG. 2a is a sectional view showing the structure of a fluidized bed heat exchanger (quench cooler) used in the present invention.
Fig. 2b is a configuration diagram of heat transfer tubes provided in the fluidized bed of the heat exchanger, Fig. 2c is an explanatory diagram of the fins arranged in the space above the fluidized bed, and Fig. 2d is an explanatory diagram of the membrane wall structure. , FIG. 3a is a sectional view showing another embodiment of the heat exchanger (quenching device) used in the present invention, and FIG. 3b is a view taken along the line A--A in FIG. 3a. 8,102,202...Cracked gas inlet conduit, 1
3,100...Heat exchanger body, 14,108,2
08...Heat transfer tube (cooling pipe), 15,105...Membrane wall (water cooling wall), 103,203...
...Heat exchanger inlet cone, 104...Cracked gas distribution plate, 106...Heat insulation layer, 107...Wear-resistant heat-resistant material, 109...Fin, 111,115...Boiler water outlet conduit, 112,212... Boiler inlet header, 113, 116...Boiler water inlet conduit, 11
4,211... Boiler water outlet header, 117...
Boiler water inlet header, 119...Cyclone, 1
20...Medium recovery conduit, 122...Cracked gas discharge pipe, 131...Medium discharge conduit, 132...Valve for medium discharge control, 133...Fluidized bed forming section, 13
4...Fluidized bed boundary, 135...Fluidized bed upper space.

Claims (1)

[Claims] 1. A fluidized bed pyrolysis furnace that pyrolyzes hydrocarbons while forming a fluidized bed using a heating medium, and the cracked gas exiting the pyrolysis furnace is introduced into the fluidized bed as a fluidizing gas, and the cracked gas is rapidly cooled. a fluidized bed type quencher that separates the generated gas, a fluidized bed type heat medium regenerator that regenerates the heat medium by burning the carbon-adhered heat medium particles generated in the quencher, and a system that recirculates the heat medium to the fluidized bed quencher via the cooler; a system that supplies carbon-attached heat medium particles generated in the pyrolysis furnace to the heat medium regenerator; and the heat medium regenerator. A hydrocarbon pyrolysis apparatus comprising: a system for recirculating heat medium particles regenerated in the pyrolysis furnace to the pyrolysis furnace.