JP5466450B2 - Operation method of continuous fluid contact aromatic production plant - Google Patents

Description

  The present invention relates to a method for operating a continuous fluidized catalytic aromatic production plant that produces aromatic hydrocarbons by a catalytic aromatic production reaction using a fluidized bed reactor.

  A method for producing aromatic hydrocarbons such as BTX (benzene, toluene, xylene, etc.) from a light naphtha, heavy naphtha, etc. obtained from a crude oil distillation apparatus by a catalytic aromatic production reaction is well known. In general, these production methods employ a fixed bed or moving bed method using a granular aromatic production catalyst.

  Since the aromatic production reaction is usually an endothermic reaction, a heat supply method for compensating for the reaction heat and a temperature control method related thereto are problems. In addition, when the raw material is light naphtha, when it becomes heavy naphtha, especially cracked light oil (light cycle oil; hereinafter referred to as LCO) from fluid catalytic cracking (hereinafter referred to as FCC) equipment, it will react. As the operation proceeds, the generation of coke is significant, and the frequency of regeneration of the aromatic production catalyst is also significant.

Therefore, in order to cope with these problems, a method using a fluidized bed has been proposed in place of a conventional method using a fixed bed or moving bed (for example, Patent Document 1).
By adopting a fluidized bed system, it is possible to maintain the reaction bed close to perfect mixing, making it easy to maintain a uniform reaction temperature and coke-degraded aroma when the raw material becomes heavier. Regeneration can be carried out smoothly by appropriately removing the group production catalyst from the fluidized bed reactor. That is, coke adheres to the aromatic production catalyst due to contact with the raw material, and the aromatic production catalyst is inactivated, so the aromatic production catalyst extracted from the fluidized bed reactor is transferred to the regenerator, and the The coke adhered to the aromatic production catalyst in the regenerator is burned in the presence of air supplied from the outside to regenerate the aromatic production catalyst, and then the regenerated aromatic production catalyst is transferred to the fluidized bed reactor. To be done.

  However, if the amount of coke adhering to the aromatic production catalyst is small in the fluidized bed reactor, the heat required for the aromatic production reaction (endothermic reaction) in the fluidized bed reactor is obtained even if the coke is burned in the regenerator. Can't get. Therefore, it is necessary to heat the raw material before being supplied to the fluidized bed reactor to the reaction temperature or higher in advance by the preheater.

  However, the heating of the raw material by the preheater cannot sufficiently supply heat to the fluidized bed reactor. In addition, when the temperature in the fluidized bed reactor rapidly decreases due to a rapid progress of the aromatic production reaction, the insufficient heat cannot be supplied quickly. However, in order to give the heat required for the aromatic production reaction (endothermic reaction) from the aromatic production catalyst in the regenerator, torch oil is injected into the regenerator catalyst bed and burned with air to raise the catalyst bed temperature. If this method is employed, a product oil containing BTX can be produced efficiently and stably.

  Moreover, in order to transfer the aromatic production catalyst regenerated in the regenerator to the fluidized bed reactor, the pressure in the regenerator needs to be higher than the pressure in the fluidized bed reactor. Therefore, it is necessary to stably supply a large amount of air for burning the coke in the regenerator to the regenerator with an air blower. Furthermore, the pressure (0.3 MPaG to 0.6 MPaG) in the fluidized bed reactor when the aromatic production reaction is performed is the same as the pressure in the normal fluidized bed reactor (for example, in the case of FCC, 0.15 MPaG to 0.2 MPaG). ), The entire reaction system including the heating tank needs to be under a higher pressure than usual.

  However, there is a case where power for supplying a large amount of air stably to the regenerator is insufficient and a large amount of air cannot be stably supplied. Therefore, the regenerated aromatic production catalyst cannot be stably transferred to the fluidized bed reactor, and a product oil containing BTX cannot be produced efficiently and stably.

Japanese National Patent Publication No. 3-503656

  The present invention provides a continuous fluidized contact aromatic production plant that produces aromatic hydrocarbons using LCO obtained from an FCC unit, naphtha from a crude distillation unit, straight-run gas oil, and the like as raw materials, efficiently and stably. Provided is an operation method capable of producing aromatic hydrocarbons and capable of reducing an increase in power accompanying a reaction system under high pressure.

  The operation method of the continuous fluidized contact aromatic production plant of the present invention is selected from the group consisting of cracked light oil obtained from an FCC unit, hydrogenated cracked light oil, naphtha from a crude oil distillation unit, straight-run gas oil, etc. One or more distillate oils contacted with an aromatic production catalyst in a fluidized bed state to obtain a reaction product containing aromatic hydrocarbons, and a heating fuel supplied from the outside By heating in the presence of an oxygen-containing gas, a heating tank for heating the aromatic production catalyst extracted from the fluidized bed reactor, and supplying the oxygen-containing gas to the heating tank An operation method of a continuous fluidized contact aromatic production plant having a blowing means, wherein the pressure in the fluidized bed reactor is 0.3 MPaG to 0.6 MPaG, and the pressure in the heating tank is fluidized bed. Reactor Higher than the pressure of, discharged from the heat with tank, the pressure energy of the combustion gas generated by the combustion of fuel for the heat with, characterized by use as a power of the blowing means.

  In the operation method of the continuous fluidized contact aromatic production plant of the present invention, the combustion gas discharged from the heating tank is passed through an expander, whereby the pressure energy of the combustion gas is converted into mechanical energy by the expander. It is preferable to convert and drive the blowing means connected to the expander by the mechanical energy.

  According to the operation method of the continuous fluidized contact aromatic production plant of the present invention, continuous fluid production of aromatic hydrocarbons using LCO obtained from the FCC unit, naphtha from the crude distillation unit, straight-run gas oil, etc. as raw materials. In the contact aromatic production plant, aromatic hydrocarbons can be produced efficiently and stably, and the increase in power associated with bringing the reaction system under high pressure can be reduced.

It is a schematic block diagram which shows an example of a continuous fluid contact aromatic manufacturing plant.

  FIG. 1 is a schematic configuration diagram illustrating an example of a continuous fluidized contact aromatic production plant. The continuous fluidized contact aromatic production plant 10 includes a fluidized bed reactor 12, a heating tank 14, a separator 16, an expander 18, an air blower 20 (air blowing means) directly connected to the expander 18, and an expander 18. And a motor / generator 22 connected to the air blower 20, a waste heat boiler 24, a catalyst riser 26 having a terminal connected to the fluidized bed reactor 12, a base end connected to the fluidized bed reactor 12, and a terminal having heat. A first inclined pipe 28 connected to the attaching tank 14, a second inclined pipe 30 having a base end connected to the heating tank 14 and a terminal end connected to the base end of the catalyst riser 26, and a terminal end of the catalyst riser 26, a feed pipe 32 connected to the base end, a discharge pipe 34 connected to the fluidized bed reactor 12 at the base end, a fuel pipe 36 connected to the heating tank 14 at the end, and an air blower 2 at the base end. , A first exhaust pipe 40 having a base end connected to the heat tank 14 and a base end connected to the separator 16, and a base end connected to the separator 16. And a second exhaust pipe 42 having a distal end connected to the expander 18 and a third exhaust pipe 44 having a proximal end connected to the expander 18 and a distal end connected to the waste heat boiler 24. .

  The fluidized bed reactor 12 is for obtaining a product oil containing a large amount of BTX by bringing the feedstock into contact with the aromatic production catalyst in a fluidized bed state, and the steam of the feedstock transferred through the catalyst riser 26. And an inlet for introducing the aromatic production catalyst, an outlet for extracting the aromatic production catalyst to the first inclined pipe 28, a cyclone for separating the generated oil vapor and the aromatic production catalyst, and separation by the cyclone And a discharge port for discharging the steam of the produced oil to the discharge pipe 34.

  The heating tank 14 is for actively heating the aromatic production catalyst by the energy supplied from the outside without depending on the heat generated by the combustion of the coke adhered to the aromatic production catalyst, that is, the heating tank 14 itself. A large heating device itself, a supply port for introducing the aromatic production catalyst transferred through the first inclined pipe 28 into the inside, an outlet for extracting the aromatic production catalyst into the second inclined pipe 30, and fuel A supply port for introducing heat-supplied fuel supplied from the outside through the pipe 36, a supply port for introducing air (oxygen-containing gas) supplied through the air pipe 38, and generated by combustion And an exhaust port for exhausting the combustion gas to the first exhaust pipe 40.

  The separator 16 is for separating the aromatic production catalyst contained in the combustion gas from the combustion gas. The aromatic production catalyst is accompanied in the combustion gas sent to the expander 18, and the expander is used by the aromatic production catalyst. It suppresses that 18 turbines wear.

  The expander 18 utilizes a differential pressure between the pressure of the combustion gas on the suction side and the pressure (atmospheric pressure) on the discharge side, and the pressure of the combustion gas is obtained by rotating the turbine with the combustion gas passing through the inside. It converts energy into rotational energy (mechanical energy) and recovers it.

  The air blower 20 rotates the rotor using the rotational force energy from the expander 18 and / or the motor / generator 22 as power and sends out air. Examples of the air blower 20 include a centrifugal type and an axial flow type.

  The waste heat boiler 24 recovers thermal energy of the combustion gas by heating water with high-temperature combustion gas discharged from the expander 18 and generating water vapor.

  The catalyst riser 26 is in the form of a pipe extending in the vertical direction, and is supplied through a feed pipe 32 and a feed port for introducing the aromatic production catalyst transferred through the second inclined pipe 30 into the interior. And a supply port for introducing the vapor of the raw material oil into the inside.

The operation of the continuous fluidized contact aromatic production plant 10 in FIG. 1 is performed as follows, for example.
Steam of raw material oil heated in advance by a preheater (not shown) provided in the middle of the feed pipe 32 is continuously introduced from the feed pipe 32 to the catalyst riser 26. At the same time, the aromatic production catalyst heated in the heating tank 14 is continuously introduced from the second inclined pipe 30 to the catalyst riser 26, and the vapor of the feed oil rising up the catalyst riser 26 is transferred to the transfer medium. To the fluidized bed reactor 12.

  The aromatic production catalyst continuously introduced from the catalyst riser 26 into the fluidized bed reactor 12 together with the raw material vapor is brought into a fluidized bed state by the raw material vapor. In the fluidized bed state, the steam of the raw oil and the aromatic production catalyst come into contact with each other, and the steam of the product oil containing a large amount of BTX is obtained. The generated oil vapor and the aromatic production catalyst are separated by a cyclone, and the generated oil vapor is continuously discharged to the discharge pipe 34 and transferred to a subsequent distillation tower (not shown) through the discharge pipe 34. . A portion of the aromatic production catalyst that has been partially deactivated with coke deposited by contact with the feedstock vapor is continuously withdrawn from the fluidized bed reactor 12 to the first inclined pipe 28.

  Heating fuel supplied from the outside through the fuel pipe 36 is combusted in the presence of air (oxygen-containing gas) supplied from the air blower 20 through the air pipe 38, so that the first inclined pipe 28 The aromatic production catalyst continuously introduced into the heating tank 14 is continuously heated above the reaction temperature in the fluidized bed reactor 12. Moreover, since coke adhering to the aromatic production catalyst also burns during heating, the aromatic production catalyst is also regenerated. The combustion gas generated by the combustion is continuously exhausted to the first exhaust pipe 40. The heated aromatic production catalyst is continuously extracted from the heating tank 14 to the second inclined pipe 30, and is again introduced from the second inclined pipe 30 into the catalyst riser 26. As described above, the aromatic production catalyst is continuously circulated between the fluidized bed reactor 12 and the heating tank 14.

  The combustion gas exhausted to the first exhaust pipe 40 is introduced into the separator 16, and the separator 16 separates the aromatic production catalyst from the combustion gas. The turbine of the expander 18 is rotated by the combustion gas continuously exhausted from the separator 16 to the second exhaust pipe 42 and introduced into the expander 18, and the pressure energy of the combustion gas is converted into rotational energy (mechanical energy). Convert and recover. After recovering thermal energy from the combustion gas exhausted continuously from the expander 18 to the third exhaust pipe 44 and introduced into the waste heat boiler 24, the combustion gas is discharged to the outside.

The supply of air to the heating tank 14 is performed as follows.
At the start of operation of the continuous fluid contact aromatic production plant 10, the motor of the motor / generator 22 is driven, the air blower 20 connected to the motor / generator 22 is driven by the rotational energy of the motor, and the air is supplied to the air pipe 38. It is fed out and supplied from the air pipe 38 to the heating tank 14.

  During normal operation of the continuous fluidized contact aromatic production plant 10, the air blower 20 disposed coaxially with the expander 18 is driven by the rotational force energy converted and recovered from the pressure energy of the combustion gas by the expander 18. The air is sent out to the air pipe 38 and supplied from the air pipe 38 to the heating tank 14. When the power of the air blower 20 is insufficient only by the rotational force energy from the expander 18, the motor of the motor / generator 22 is driven and the power is supplemented by the rotational force energy of the motor. When surplus rotational energy is generated from the expander 18, the generator of the motor / generator 22 is driven, and the surplus rotational energy is recovered as electric energy.

  As the raw material oil, one or more selected from the group consisting of LCO obtained from an FCC unit, hydrogenated LCO, naphtha from a crude distillation unit, straight-run gas oil, and the like are used. When these raw material oils are used, the amount of coke that adheres to the aromatic production catalyst when the raw material oil comes into contact with the aromatic production catalyst is not necessarily large. Moreover, the pressure of the reaction system when performing the aromatic production reaction of these feedstock oils is higher than that of the FCC apparatus. Therefore, the operation method of the present invention is effective in order to efficiently and stably produce a product oil containing aromatic hydrocarbons from these feedstock oils.

The aromatic production catalyst contains crystalline aluminosilicate.
Although content of crystalline aluminosilicate is not specifically limited, 10-95 mass% is preferable, 20-80 mass% is more preferable, 25-70 mass% is further more preferable.

  Although it does not specifically limit as crystalline aluminosilicate, For example, the zeolite of MFI, MEL, TON, MTT, MRE, FER, AEL, EUO type which is a medium pore diameter zeolite is preferable, MFI type and / or MEL type crystal structure The body is more preferred. Crystalline aluminosilicates such as MFI type and MEL type belong to a known zeolite structure type of the kind published by The Structure Commission of the International Zeolite Association (Atlas of Zeolite M. StruD. Olson (1978) .Distributed by Polycyclic Book Service, Pittsburgh, PA, USA).

As the crystalline aluminosilicate, those containing gallium are preferable. By containing gallium, BTX can be produced more efficiently, and at the same time, the by-product of the non-aromatic hydrocarbon having 3 to 6 carbon atoms can be greatly suppressed.
Crystalline aluminosilicates containing gallium include those in which gallium is incorporated in the lattice skeleton of crystalline aluminosilicate (crystalline aluminogallosilicate), and crystalline aluminosilicate carrying gallium (Ga-supporting crystalline aluminosilicate) ), Which includes both.

  The Ga-supporting crystalline aluminosilicate is obtained by supporting gallium on a crystalline aluminosilicate by a known method such as an ion exchange method or an impregnation method. The gallium source used at this time is not particularly limited, and examples thereof include gallium salts such as gallium nitrate and gallium chloride, and gallium oxide.

Crystalline aluminogallosilicate is a structure in which SiO ₄ , AlO ₄ and GaO ₄ structures are tetrahedrally coordinated in the skeleton. Gel crystallization by hydrothermal synthesis, and gallium in the lattice skeleton of crystalline aluminosilicate. It can be obtained by an insertion method or a method of inserting aluminum into the lattice skeleton of crystalline gallosilicate.
The particle size of the crystalline aluminosilicate is usually from 0.01 to 2 μm, preferably from 0.02 to 1 μm.

The fuel for heating is a fuel other than coke adhering to the aromatic production catalyst and is supplied from the outside (so-called torch oil), for example, the production obtained in the continuous fluid contact aromatic production plant 10 Examples include distillation tower bottom oil, etc. In particular, from the viewpoint of avoiding the problem of deterioration of the aromatic production catalyst due to water vapor, distillation tower bottom oil having a relatively large ratio of carbon atoms to hydrogen atoms (C / H) is used. preferable.
Examples of the oxygen-containing gas include air, pure oxygen, and the like, and air is preferable from an economical viewpoint.

  The heating temperature of the raw material oil by the preheater (not shown) is such that the heat required for the aromatic production reaction in the fluidized bed reactor 12 is supplied by the heated aromatic production catalyst. It may be less than the reaction temperature within 12, and is preferably 250 to 450 ° C.

  The pressure in the fluidized bed reactor 12 is 0.3 MPaG to 0.6 MPaG, preferably 0.3 MPaG to 0.5 MPaG, and more preferably 0.3 MPaG to 0.4 MPaG. If the pressure in the fluidized bed reactor 12 is 0.3 MPaG or more, BTX can be produced efficiently. However, if the pressure in the fluidized bed reactor 12 exceeds 0.6 MPaG, the pressure of the exhaust gas from the heating tank 14 becomes too high, so the expander 18 is designed to withstand the high pressure of the exhaust gas. As a result, the expander 18 becomes special, leading to an increase in plant costs. Moreover, when the pressure in the fluidized bed reactor 12 exceeds 0.6 MPaG, the yield of BTX also decreases.

  350-700 degreeC is preferable and, as for the reaction temperature in the fluidized bed reactor 12, 520-600 degreeC is more preferable. If reaction temperature is 350 degreeC or more, the activity of an aromatic production catalyst will become enough. If reaction temperature is 700 degrees C or less, an excessive decomposition reaction will be suppressed.

  The contact time between the raw material oil, the aromatic production catalyst and the fluidized bed reactor 12 is preferably 5 to 30 seconds, and more preferably 15 to 20 seconds. If the contact time is 5 seconds or more, the aromatic production reaction proceeds sufficiently. If the contact time is 30 seconds or less, the amount of light gas by-produced by decomposition can be suppressed.

  The amount (circulation amount) of the aromatic production catalyst withdrawn from the fluidized bed reactor 12 is preferably 5 to 30 tons per ton of feedstock supplied to the fluidized bed reactor 12, and this is the total heat balance. It is related and decided.

The pressure in the heating tank 14 is such that when the heating tank 14 is placed at a position lower than the fluidized bed reactor 12, the heated aromatic production catalyst is transferred to the fluidized bed reactor 12. Higher than the pressure in the vessel 12. The pressure in the heating bath 14 is preferably about 0.05 MPa higher than the pressure in the fluidized bed reactor 12, and more preferably 0.03 MPa to 0.10 MPa.
The pressure in the heating tank 14 is adjusted by the amount of air from the air blower 20 and an adjusting valve provided in the middle of the exhaust pipe.

  The temperature in the heating tank 14 is the reaction temperature in the fluidized bed reactor 12 because the heat required for the aromatic production reaction in the fluidized bed reactor 12 is supplied by the heated aromatic production catalyst. It is above, 500-800 degreeC is preferable and 600-700 degreeC is more preferable.

  The amount of fuel for heating (in the case of distillation tower bottom oil) supplied to the heating tank 14 is preferably 0.02 to 0.08 tons per ton of feedstock supplied to the fluidized bed reactor 12, Determined from coke production and overall heat balance.

  In the operation method of the continuous fluidized contact aromatic production plant of the present invention described above, the aromatic production catalyst extracted from the fluidized bed reactor is used, and the heating fuel supplied from the outside contains oxygen. Because it is heated in the heating tank by burning it in the presence of gas, it does not depend on the heat of combustion of coke adhering to the aromatic production catalyst, but by the heating fuel supplied from the outside The heat necessary for the aromatic production catalyst (endothermic reaction) in the fluidized bed reactor can be sufficiently supplemented efficiently and stably by the actively heated aromatic production catalyst. Therefore, even when a raw material oil (such as LCO) that reduces the amount of coke that adheres to the aromatic production catalyst when in contact with the aromatic production catalyst is used as a raw material, it is efficiently and stably used. BTX can be manufactured.

  Further, in the operation method of the continuous fluidized contact aromatic production plant of the present invention described above, the pressure energy of the combustion gas generated by the combustion of the fuel for heating discharged from the heating tank is blown. Therefore, a large amount of air can be stably supplied to the heating tank without the power of the blowing means being insufficient. Therefore, the aromatic production catalyst regenerated in the heating tank can be stably transferred to the fluidized bed reactor, and BTX can be produced efficiently and stably. In particular, since the aromatic production reaction in the continuous fluid contact aromatic production plant is performed at a high pressure (0.3 MPaG to 0.6 MPaG), the pressure energy of the combustion gas discharged from the heating tank is also sufficiently high. By recovering this high pressure energy, an increase in power associated with bringing the reaction system under high pressure can be sufficiently reduced.

Examples are shown below.
[Example 1]
Using the continuous fluidized contact aromatic production plant 10 having the configuration shown in FIG. 1, BTX was produced under the following operating conditions, and the production amount of BTX and the like were obtained by calculation based on this data.

(Operating conditions)
Heating temperature of raw material oil by a preheater (not shown): 410 ° C.
Feed rate of raw material oil (steam) to the catalyst riser 26: 100 ton / hr,
Pressure in fluidized bed reactor 12: 0.3 MPaG,
Reaction temperature in fluidized bed reactor 12: 560 ° C.
Contact time between the feedstock and the aromatic production catalyst in the fluidized bed reactor 12: 18 seconds,
Pressure in the heating bath 14: 0.35 MPaG,
Temperature in the heating tank 14: 650 ° C.
Supply amount of fuel for heating to the heating tank 14: 0.055 tons / one ton of raw oil
Supply amount of air to the heating tank 14: 0.80 ton / one ton of raw oil
Circulation amount of aromatic production catalyst: 17.6 tons / one ton of feedstock,

Note that LCO was used as the raw material oil.
As the heating fuel (torch oil), the bottom oil of the product oil was used.
As the aromatic production catalyst, an aromatic production catalyst containing MFI type zeolite (particle size: about 0.3 μm) in which gallium was incorporated in the lattice skeleton was used.

During operation, heat can be efficiently supplied to the fluidized bed reactor 12 by the aromatic production catalyst heated in the heating tank 14, and the temperature in the fluidized bed reactor 12 does not fluctuate greatly, and it is stably generated. An oil could be obtained. The amount of BTX contained in the product oil was 43% by mass.
Further, during normal operation of the continuous fluid contact aromatic manufacturing plant 10, the expander 18 can drive the air blower 20 with only the rotational energy converted and recovered from the pressure energy of the combustion gas, and a sufficient amount. The air was efficiently and stably supplied to the heating tank 14.

  INDUSTRIAL APPLICABILITY The present invention is useful for the production of aromatic hydrocarbons using LCO obtained from an FCC apparatus, naphtha from a crude oil distillation apparatus, and the like as raw materials.

DESCRIPTION OF SYMBOLS 10 Continuous fluid contact aromatic production plant 12 Fluidized bed reactor 14 Heating tank 18 Expander 20 Air blower (blower means)

Claims (2)

One or more distillate oils selected from the group consisting of cracked gas oil obtained from a fluid catalytic cracker, hydrocracked gas oil, and naphtha and straight-run gas oil from a crude distillation apparatus are in a fluidized bed state. A fluidized bed reactor in contact with an aromatic production catalyst to obtain a reaction product containing an aromatic hydrocarbon;
A heating tank that heats the aromatic production catalyst extracted from the fluidized bed reactor by burning an externally supplied heating fuel in the presence of an oxygen-containing gas;
An operation method of a continuous fluidized contact aromatic production plant having a blowing means for supplying the oxygen-containing gas to the heating tank,
The content of crystalline aluminosilicate in the aromatic production catalyst is 10 to 95% by mass,
The amount of the aromatic production catalyst extracted from the fluidized bed reactor is 5 to 30 tons per ton of feedstock supplied to the fluidized bed reactor,
The pressure in the fluidized bed reactor is 0.3 MPaG to 0.4 MPaG,
The pressure in the heating tank is set to 0.03 MPa to 0.10 MPa higher than the pressure in the fluidized bed reactor,
A method for operating a continuous fluidized contact aromatic production plant, wherein pressure energy of combustion gas generated by combustion of the fuel for heating that is discharged from the heating tank is used as power for the blowing means. . By passing the combustion gas discharged from the heating tank through an expander, the pressure energy of the combustion gas is converted into mechanical energy by the expander;
The operation method of the continuous fluid contact aromatic manufacturing plant of Claim 1 which drives the said ventilation means connected to the said expander with this mechanical energy.

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