A sulfuric acid alkylation reactor sealing, flushing system and method

Abstract

The present application relates to the technical field of alkylation device modification in petroleum refining, and particularly relates to a sealing and flushing system and method for a sulfuric acid alkylation reactor, comprising a shaft sleeve arranged outside a shaft, wherein the shaft sleeve is connected in series from a medium side to an atmosphere side with a protective sleeve, an auxiliary shaft sleeve, a primary seal, a self-aligning roller bearing, a secondary seal, a throttle ring and a wedge-shaped shaft holder; the end face outer diameter, the end face inner diameter, the balance diameter and the material of the dynamic ring and the static ring in the primary seal and the secondary seal are technically improved, so that the end face temperature rise is reduced, the liquid film formation between the dynamic ring and the static ring is more stable, the end face closure and the anti-large torque mutation of the seal are improved, the mutation collision or edge collapse of the dynamic ring and the static ring is effectively prevented to cause medium leakage, and the long-period operation target of the reactor, a core device of the alkylation device, is achieved. The problem of high sealing leakage rate of the alkylation device reactor in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of alkylating unit modification in petroleum refining, in particular to a sealing and flushing system and method for a sulfuric acid alkylating reactor. BACKGROUND

[0002] The alkylating unit is used to generate high-octane alkylated oil by reacting isobutane and C4 olefins. The product has the following characteristics: zero aromatic hydrocarbons, zero benzene, zero olefins, high octane, low sulfur, low vapor pressure, good stability, low toxicity, no corrosion, easy storage and transportation. As a gasoline blending component, it can improve the starting performance of the automobile, make the gasoline burn completely, reduce the CO content in the automobile exhaust, and reduce hydrocarbons. It is an ideal blending component for high-octane gasoline and plays a key role in the production of high-octane gasoline, which has great economic value.

[0003] The key core equipment in the alkylating unit is two horizontal stirring reactors. The reactor has a seal and a matching seal flushing oil station, stirring paddles, an internal circulation sleeve, and a U-shaped heat exchange tube bundle for carrying away the reaction heat. In the prior art, according to the mechanical seal standard API682, the PLAN32+PLAN54+PLAN61 flushing mode is used to provide circulating flushing seal liquid for the seal, carry away the heat of the seal cavity, and ensure the normal operation of the seal. Referring to Figures 1 to 3 , the PLAN32 flushing mode in the API682 standard mainly uses an external flushing medium to enter the seal cavity through a flushing interface to lubricate and carry away the heat of the medium side of the dynamic and static rings of the seal cavity. The PLAN54 flushing mode in the API682 standard mainly provides clean seal flushing liquid to the seal cavity from an external pressurized isolation tank. The seal flushing liquid circulates to carry away the heat of the atmospheric side of the dynamic and static rings of the seal cavity. Unlike the PLAN32 mode, the PLAN54 flushing liquid enters the cycle from the isolation liquid inlet position and flows out from the isolation liquid outlet. The PLAN61 flushing mode in the API682 standard is basically the same as the PLAN54 scheme, which also lubricates and carries away the heat of the medium side of the dynamic and static rings of the seal cavity. It is mainly used to assist the PLAN54 flushing mode, which is not used in daily operation. The inlet and outlet are sealed with plugs to prevent contamination in the seal cavity.

[0004] However, the existing reactor seal has the problems of high heat generation at the seal end face, easy rubbing and edge collapse of the dynamic and static rings, corrosion of the auxiliary seal and other original components, high leakage rate of external seepage, high maintenance cost, and inability to meet the long-period operation target of the core equipment of the alkylating unit. SUMMARY

[0005] In view of the high leakage rate of the reactor seal in the prior art, the present application provides a sealing and flushing system and method for a sulfuric acid alkylating reactor.

[0006] To achieve the above object, the application adopts the following technical solutions:

[0007] The application provides a sealing device for a sulfuric acid alkylation reactor, which comprises a shaft sleeve arranged outside a shaft, and a protective sleeve, an auxiliary shaft sleeve, a primary seal, a self-aligning roller bearing, a secondary seal, a throttle ring and a wedge-shaped shaft holder are sequentially connected in series from a medium side to an atmosphere side.

[0008] The primary seal comprises a sealing medium side moving ring, and a sealing medium side static ring is connected to the sealing medium side moving ring; the auxiliary shaft sleeve is arranged between the protective sleeve and the sealing medium side moving ring, and is used for adjusting the balance diameter of the sealing medium side moving ring; the difference between the end face inner diameter of the connection end of the sealing medium side moving ring and the outer diameter of the shaft sleeve is 6mm±0.5mm; the difference between the end face outer diameter of the connection end of the sealing medium side moving ring and the outer diameter of the shaft sleeve is 16mm±0.5mm; and the difference between the balance diameter of the sealing medium side moving ring and the outer diameter of the shaft sleeve is 8mm±0.5mm.

[0009] The secondary seal comprises a sealing atmosphere side moving ring, and a sealing atmosphere side static ring is connected to the sealing atmosphere side moving ring; a groove is arranged on the shaft sleeve at a position corresponding to the secondary seal, and is used for adjusting the balance diameter of the sealing atmosphere side moving ring; the difference between the end face outer diameter of the connection end of the sealing atmosphere side moving ring and the outer diameter of the shaft sleeve is 8mm±0.5mm; the difference between the end face inner diameter of the connection end of the sealing atmosphere side moving ring and the outer diameter of the shaft sleeve is-3mm±0.5mm; and the difference between the balance diameter of the sealing atmosphere side moving ring and the outer diameter of the shaft sleeve is 0mm.

[0010] Preferably, the material of the sealing atmosphere side moving ring is graphite.

[0011] Preferably, the self-aligning roller bearing is limited by a round nut.

[0012] Preferably, a stop washer is arranged between the self-aligning roller bearing and the round nut.

[0013] Preferably, the materials of the sealing medium side moving ring and the sealing medium side static ring are both pressureless sintered silicon carbide.

[0014] The application further provides a flushing system comprising the above-mentioned sealing device for a sulfuric acid alkylation reactor, which comprises an oil tank, an oil pump is arranged in the oil tank, the outlet of the oil pump is connected to the atmosphere side flushing medium inlet of the sealing device for a sulfuric acid alkylation reactor, the atmosphere side flushing medium outlet of the sealing device for a sulfuric acid alkylation reactor is connected to the inlet of the oil tank, and the outlet of the oil pump is further connected to an energy storage tank; and the medium side flushing inlet of the sealing device for a sulfuric acid alkylation reactor is connected to a reactor.

[0015] Preferably, the inlet of the oil pump is connected to a filter.

[0016] Preferably, a regulating valve is arranged between the outlet of the reactor sealed atmospheric side flushing medium and the inlet of the oil tank.

[0017] Preferably, a pressure gauge and a second ball valve are arranged between the regulating valve and the outlet of the reactor sealed atmospheric side flushing medium.

[0018] A flushing method using the above flushing system, comprising the following steps:

[0019] The pressure of the air bag inside the energy storage tank is 0.05MPa to 0.1MPa higher than the target pressure of the atmospheric side flushing liquid;

[0020] The liquid level of the atmospheric side flushing medium inside the oil tank accounts for 65% to 85% of the volume of the oil tank;

[0021] The oil pump is started, and the pressure of the oil pump is adjusted so that the atmospheric side flushing pressure is 0.14MPa to 0.41MPa higher than the pressure of the medium side flushing liquid;

[0022] The medium side flushing is started, and the pressure of the medium side flushing liquid before entering the reactor is 0.15MPa to 0.35MPa higher than the pressure inside the reactor;

[0023] After the pressure of the oil pump and the pressure of the medium side flushing liquid are adjusted, the reactor is fed until the pressure inside the reactor reaches the normal production pressure;

[0024] After the pressure inside the reactor reaches the normal production pressure, the pressure of the oil pump is adjusted to the target pressure of the atmospheric side flushing liquid, the atmospheric side flushing liquid enters the sealed cavity, and forms a liquid film between the sealed atmospheric side moving ring and the sealed atmospheric side stationary ring, and then returns to the oil tank; the pressure of the medium side flushing liquid is adjusted to the target pressure of the medium side flushing liquid, the medium side flushing liquid enters the sealed cavity, and forms a liquid film between the sealed medium side moving ring and the sealed medium side stationary ring;

[0025] After the pressure of the oil pump and the pressure of the atmospheric side flushing medium are adjusted to the target pressure, it is checked whether there is leakage at each sealing point;

[0026] After confirming that there is no leakage at each sealing point, the stirring motor is started to run, and production is entered;

[0027] After the production is completed, the stirring motor is turned off, the pressure inside the reactor is released for replacement, the medium side flushing is stopped, and the flushing of the seal is completed.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] The present invention provides a seal for a sulfuric acid alkylation reactor, comprising a sleeve sleeved on the outer side of a shaft, wherein the sleeve is sequentially connected in series with a protective sleeve, an auxiliary sleeve, a primary seal, a spherical roller bearing, a secondary seal, a throttling ring and a wedge-shaped shaft clamp from the medium side to the atmosphere side; the difference between the inner diameter of the end face of the connection end between the sealing medium side dynamic ring and the sealing medium side static ring in the primary seal and the outer diameter of the sleeve is creatively set to 6mm±0.5mm, the difference between the outer diameter of the end face of the connection end between the sealing medium side dynamic ring and the sealing medium side static ring and the outer diameter of the sleeve is set to 16mm±0.5mm, and the difference between the balance diameter and the outer diameter of the sleeve is set to 8mm±0.5mm. This can achieve better sealing end face closure when the elastic force difference is not large, and can effectively prevent the seal from being unable to close due to sudden changes in torque during the start-up and shutdown process, resulting in a seal failure. In order to prevent leakage of the seal, a groove is creatively set on the sleeve at the position corresponding to the secondary seal to adjust the balance diameter of the dynamic ring on the atmosphere side of the seal; the difference between the outer diameter of the connection end face of the dynamic ring on the atmosphere side and the static ring on the atmosphere side and the outer diameter of the sleeve is 8mm±0.5mm; the difference between the inner diameter of the connection end face of the dynamic ring on the atmosphere side and the static ring on the atmosphere side and the outer diameter of the sleeve is -3mm±0.5mm; the difference between the balance diameter of the dynamic ring on the atmosphere side and the outer diameter of the sleeve is 0mm. This setting can make the thickness of the dynamic rings on the atmosphere side and the medium side thicker and have a higher pressure-bearing capacity of up to 10MPa, which effectively avoids the problem of sealing ring cracking due to excessive internal pressure, and can reduce the heat generation of the seal to 829008J / Hr, which is nearly 50000J / Hr lower than the heat generation of the original design. The heat generated by the end faces of the primary and secondary seals of the reactor seal is reduced, the temperature rise of the end faces is reduced, and the possibility of liquid vaporization at the end faces is reduced, making the liquid film formation between the dynamic ring on the sealing medium side and the static ring on the sealing medium side more stable. At the same time, the end face closure and resistance to large torque mutations of the seal are improved, which can effectively prevent accidents caused by medium leakage due to high heat generation on the end face between the dynamic ring on the sealing medium side and the static ring on the sealing medium side, reduce the equipment maintenance cost due to corrosion due to medium leakage, and improve the stability of long-term operation and production of the equipment.

[0030] The material of the sealing atmospheric side dynamic ring is graphite. Since graphite has good self-lubricating properties, it can effectively reduce the possibility of severe wear caused by dry friction on the end faces between the atmospheric side sealing atmospheric side dynamic ring and the sealing atmospheric side static ring, thereby reducing the medium leakage caused by the wear of the atmospheric side sealing dynamic ring and affecting production.

[0031] A plurality of first sealing rings are arranged between the shaft sleeve and the shaft, which can further improve the sealing effect of the reactor.

[0032] The material of the sealing medium side moving ring and the sealing medium side static ring is pressureless sintered silicon carbide, and the ordinary reaction sintered silicon carbide is prepared by the reaction of silicon and carbon, and the free silicon content in the final material is generally 8% to 12%, the free silicon can be corroded by strong acid and strong alkali, API682 recommends that the pH value is between 4 to 11 for use, and the pressureless sintered silicon carbide is completely composed of silicon carbide, which is formed by pure silicon carbide powder and non-oxidizing sintering agent, and the structure is uniform silicon carbide without free silicon, and the characteristics make the pressureless sintered silicon carbide have chemical stability in all corrosive environments, so that the chemical corrosion resistance is better, and the performance is more stable and reliable.

[0033] The present application provides a kind of including the flushing system of the sealing of above-mentioned sulfuric acid method alkylating reactor, including oil tank, oil pump is arranged in the inside of oil tank, and the outlet of oil pump is connected with the atmosphere side flushing medium inlet of reactor sealing, and the atmosphere side flushing medium outlet of reactor sealing is connected with the inlet of oil tank;The outlet of oil pump is also connected with energy storage tank, can realize that the atmosphere side flushing fluid is filled in the liquid film formed between sealing atmosphere side moving ring and sealing atmosphere side static ring, plays lubricating effect while taking away heat, further reduces the possibility of leakage caused by sealing atmosphere side moving ring and static ring wear;The reactor sealing medium side flushing inlet is connected with reactor, can realize that medium is filled in the liquid film formed between sealing medium side moving ring and sealing medium side static ring, plays lubricating effect while taking away heat.

[0034] The inlet of the oil pump is connected with a filter, which can effectively filter the impurities in the atmosphere side flushing fluid and prevent the oil pump from being damaged.

[0035] The atmosphere side flushing medium outlet of the reactor sealing and the inlet of the oil tank are provided with a regulating valve for adjusting the flow of the atmosphere side flushing medium outlet of the reactor sealing.

[0036] The regulating valve and the atmosphere side flushing medium outlet of the reactor sealing are provided with a pressure gauge and a second ball valve for monitoring the pressure of the atmosphere side flushing medium outlet of the reactor sealing and pressure regulation.

[0037] The application also provides a flushing method using the above flushing system, which controls the pressure of the air bag inside the energy storage tank to be 0.05-0.1 MPa higher than the target pressure of the medium-side flushing liquid, controls the liquid level of the atmosphere-side flushing medium inside the oil tank to account for 65-85% of the volume of the oil tank, adjusts the pressure of the oil pump so that the pressure of the atmosphere-side flushing liquid is 0.14-0.41 MPa higher than the pressure of the medium-side flushing liquid, makes the pressure of the medium-side flushing liquid before entering the reactor seal 0.15-0.35 MPa higher than the pressure inside the reactor, slowly feeds the reactor until the pressure inside the reactor reaches the normal production pressure, adjusts the pressure of the oil pump to the target pressure of the atmosphere-side flushing liquid, makes the atmosphere-side flushing liquid enter the inside of the seal cavity and form a liquid film between the seal atmosphere-side moving ring and the seal atmosphere-side stationary ring, then returns to the oil tank, adjusts the pressure of the medium-side flushing liquid to the target pressure of the medium-side flushing liquid, makes the medium-side flushing liquid enter the inside of the seal cavity and form a liquid film between the seal medium-side moving ring and the seal medium-side stationary ring, after adjusting the pressure of the oil pump and the pressure of the atmosphere-side flushing medium to the target pressure, checks whether there is leakage at each sealing point, confirms that there is no leakage at each sealing point, starts the stirring motor to run, and enters production, after production is completed, the stirring motor is turned off, the pressure inside the reactor is released for replacement, the medium-side flushing is stopped first, then the atmosphere-side flushing is stopped, and it is ensured that the pressure inside the reactor is 0 MPa before stopping the atmosphere-side flushing, and the flushing is completed. Through the adjustment and control of the system, the stability of the equipment operation is further improved, and it is more suitable for long-period production requirements.

[0038] Through actual inspection, the method and system can make the two reactors of the alkylation device run for nearly 25 months before the overhaul shutdown, and no shutdown event caused by sealing failure occurs during the period. The sealing of the alkylation device reactor is realized “zero leakage” and safe and stable long-period operation. Compared with similar devices, the sealing of the reactor is reduced by at least 4 times in 2 years, and the cumulative non-scheduled shutdown and maintenance is eliminated for about 16-18 days, the maintenance cost is saved, the safe and environmentally friendly long-period operation is ensured, and the economic benefit is greatly improved.

[0039] According to the calculation of the processing capacity loss of the single alkylating device reactor maintenance, the processing capacity of the alkylating device during single operation is at least 10-12t / h less than that during two simultaneous operations, and the maintenance time of each reactor is at least 6d, including 4d for isolation replacement and 2d for maintenance. Therefore, the processing capacity loss of each reactor during each maintenance is about 6d*24h*10t / h=1440t. The raw material of the alkylating device is liquefied gas, and the octane number of the alkylated product oil is generally about 97. According to the difference between the 95# gasoline delivery price and the liquefied gas price, the processing capacity benefit loss of each reactor during each maintenance is at least 3.42 million yuan. According to the calculation of the benefit loss of the single reactor during single maintenance, at least two maintenance times of the alkylating device reactor are effectively avoided in nearly one year. According to the benefit calculation of the loss of the single reactor during single maintenance, the cumulative benefit is about 6.84 million yuan in nearly one year. It can be seen that the bill has produced huge economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 It is a PLAN32 flushing seal cavity structure diagram in the prior art API682 standard.

[0041] Figure 2 It is a PLAN54 flushing seal cavity structure diagram in the prior art API682 standard.

[0042] Figure 3 It is a PLAN61 flushing seal cavity structure diagram in the prior art API682 standard.

[0043] Figure 4 It is a schematic diagram of a sulfuric acid alkylation reactor seal of the application.

[0044] Figure 5 It is a structure diagram of a sulfuric acid alkylation reactor seal flushing system of the application.

[0045] Figure 6 It is a flow chart of a sulfuric acid alkylation reactor seal flushing method of the application.

[0046] Among them, 1 is a protective sleeve, 2 is a sealing ring, 3 is a tight nail screw, 4 is an auxiliary shaft sleeve, 5 is a primary seal, 6 is a shaft sleeve, 7 is a round nut, 8 is a stop washer, 9 is a self-aligning roller bearing, 10 is a secondary seal, 11 is a wedge-shaped shaft holder, 12 is a throttle ring, 13 is a sealing medium side moving ring, 14 is a sealing medium side static ring, 15 is a sealing atmosphere side moving ring, 16 is a sealing atmosphere side static ring, 17 is a liquid discharge valve, 18 is a motor, 19 is a one-way valve, 20 is an oil tank, 21 is an oil pump, 22 is a reactor seal, 23 is an energy storage tank, 24 is a filter, 25 is a regulating valve, 26 is a pressure gauge, 27 is a second ball valve, 28 is a first ball valve, and 29 is a third ball valve. DETAILED DESCRIPTION

[0047] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Generally, the components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0048] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative work fall within the scope of protection of the present application.

[0049] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0050] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is used, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0051] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0052] In the description of the embodiments of the present application, it should also be noted that unless otherwise explicitly specified and limited, if the terms "arrangement", "installation", "connection", "connection" appear, they should be understood in a broad sense, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, can be electrically connected; can be directly connected, can be indirectly connected through an intermediate medium, or can be the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0053] The application will be further described in detail below with reference to specific embodiments, which are intended to explain but not limit the application.

[0054] Referring to Figure 4 The application discloses a sealing device for a sulfuric acid alkylation reactor, which comprises a shaft sleeve 6 sleeved outside a shaft, wherein the shaft sleeve 6 is sequentially connected in series from a medium side to an atmosphere side with a protective sleeve 1, an auxiliary shaft sleeve 4, a primary seal 5, a self-aligning roller bearing 9, a secondary seal 10, a throttle ring 12 and a wedge-shaped shaft holder 11.

[0055] A plurality of first sealing rings 2 are arranged between the shaft sleeve 6 and the shaft; the primary seal 5 comprises a sealing medium side moving ring 13, and the sealing medium side moving ring 13 is connected with a sealing medium side stationary ring 14.

[0056] The auxiliary shaft sleeve 4 is arranged between the protective sleeve 1 and the sealing medium side moving ring 13, and is used for adjusting a balance diameter of the sealing medium side moving ring 13; the shaft sleeve 4 and the protective sleeve 1 are fastened through a fastening screw 3.

[0057] A difference between an inner diameter of an end face of a connecting end of the sealing medium side moving ring 13 and the sealing medium side stationary ring 14 and an outer diameter of the shaft sleeve 6 is 6mm±0.5mm.

[0058] A difference between an outer diameter of the end face of the connecting end of the sealing medium side moving ring 13 and the sealing medium side stationary ring 14 and the outer diameter of the shaft sleeve 6 is 16mm±0.5mm.

[0059] A difference between the balance diameter and the outer diameter of the shaft sleeve 6 is 8mm±0.5mm.

[0060] The self-aligning roller bearing 9 is limited by a round nut 7, and a stop washer 8 is arranged between the self-aligning roller bearing 9 and the round nut 7.

[0061] The secondary seal 10 comprises a sealing atmosphere side moving ring 15, and the sealing atmosphere side moving ring 15 is connected with a sealing atmosphere side stationary ring 16; a groove is arranged on the shaft sleeve 6 at a position corresponding to the secondary seal 10, and is used for adjusting a balance diameter of the sealing atmosphere side moving ring 15; a difference between an outer diameter of an end face of a connecting end of the sealing atmosphere side moving ring 15 and the sealing atmosphere side stationary ring 16 and an outer diameter of the shaft sleeve 6 is 8mm±0.5mm; a difference between an inner diameter of the end face of the connecting end of the sealing atmosphere side moving ring 15 and the sealing atmosphere side stationary ring 16 and the outer diameter of the shaft sleeve 6 is -3mm±0.5mm; and a difference between the balance diameter of the sealing atmosphere side moving ring 15 and the outer diameter of the shaft sleeve is 0mm.

[0062] Preferably, a material of the sealing atmosphere side moving ring 15 is graphite; and materials of the sealing medium side moving ring 13 and the sealing medium side stationary ring 14 are pressureless sintered silicon carbide.

[0063] Referring to Figure 5The application further provides a flushing system comprising the above-mentioned sulfuric acid method alkylating reactor seal, comprising an oil tank 20, which is provided with a liquid discharge port at the bottom, and the liquid discharge port is provided with a liquid discharge valve 17; the inside of the oil tank 20 is provided with an oil pump 21, and the oil pump 21 is connected with a motor 18; the inlet of the oil pump 21 is connected with a filter 24; the outlet of the oil pump 21 is provided with a one-way valve 19, and the one-way valve 19 and the outlet of the oil pump 21 are provided with a first ball valve 28; the outlet of the oil pump 21 is connected with the atmospheric side flushing medium inlet of the reactor seal 22, and the atmospheric side flushing medium outlet of the reactor seal 22 is connected with the inlet of the oil tank 20; the atmospheric side flushing medium outlet of the reactor seal 22 and the inlet of the oil tank 20 are provided with an adjusting valve 25, and the adjusting valve 25 and the atmospheric side flushing medium outlet of the reactor seal 22 are provided with a pressure gauge 26 and a second ball valve 27; the outlet of the oil pump 21 is further connected with an energy storage tank 23, and the energy storage tank 23 and the outlet of the oil pump 21 are provided with a third ball valve 29; the medium inlet of the reactor seal 22 is connected with a reactor.

[0064] Referring to Figure 6 A flushing method of the above-mentioned flushing system, comprising the following steps:

[0065] S1: the pressure of the air bag inside the energy storage tank 23 is 0.05MPa-0.1MPa higher than the atmospheric side flushing liquid pressure;

[0066] S2: the liquid level of the atmospheric side flushing medium inside the oil tank 20 accounts for 65%-85% of the volume of the oil tank 20;

[0067] S3: the oil pump 21 is started, and the pressure of the oil pump 21 is adjusted, so that the atmospheric side flushing pressure is 0.14MPa-0.41MPa higher than the target pressure of the medium side flushing liquid;

[0068] S4: the medium side flushing is started, and the pressure of the medium side flushing liquid before entering the reactor seal is 0.15MPa-0.35MPa higher than the pressure inside the reactor;

[0069] S5: after the pressure of the oil pump 21 and the pressure of the medium side flushing liquid are adjusted, the reactor is fed until the pressure inside the reactor reaches the normal production pressure;

[0070] S6: after the pressure inside the reactor reaches the normal production pressure, the pressure of the oil pump 21 is adjusted to the target pressure of the atmospheric side flushing liquid, the atmospheric side flushing liquid enters the inside of the seal cavity, and forms a liquid film between the sealing atmospheric side moving ring 15 and the sealing atmospheric side static ring 16, and then returns to the oil tank 20; the pressure of the medium side flushing liquid is adjusted to the target pressure of the medium side flushing liquid, the medium side flushing liquid enters the inside of the seal cavity, and forms a liquid film between the sealing medium side moving ring 13 and the sealing medium side static ring 14;

[0071] S7: After adjusting the pressure of the oil pump 21 and the atmospheric side flushing medium pressure to the target pressure, check whether there is leakage at each sealing point;

[0072] S8: After confirming that there is no leakage at each sealing point, start the stirring motor to operate and enter production;

[0073] S9: After production is completed, close the stirring motor and depressurize the inside of the reactor for replacement, then stop the sealing medium side flushing, and then stop the sealing atmospheric side flushing to end the sealing flushing. Before stopping the atmospheric side flushing, make sure that the pressure inside the reactor is 0 MPa. After the stirring motor is stable for 1-2 hours and the pressure inside the reactor is stable for 1-2 hours after depressurization and replacement, stop the sealing flushing of the atmospheric side. It is particularly important to note that after maintenance, after starting the oil pump 21 for the first time, open the pressure relief valve to discharge the air remaining in the pipeline to the oil tank 20 to avoid gas entering the sealing cavity and causing sealing failure. Secondly, as long as there is corrosive medium and pressure in the reactor, the atmospheric side flushing liquid transmission cannot be stopped, and the atmospheric side flushing pressure should be 0.15-0.41 MPa higher than the medium side flushing pressure, and the medium side flushing pressure before entering the reactor sealing should be 0.15-0.35 MPa higher than the pressure inside the reactor. That is, the atmospheric side flushing pressure > medium side flushing pressure > pressure inside the reactor, to avoid the backflow of the medium, such as concentrated sulfuric acid, due to the decrease of the atmospheric side flushing pressure, and damage the sealing.

[0074] At the same time, if you want to further improve the stable operation period of the equipment, you also need to optimize the stirring paddle differential pressure and current operation, that is, the guide cylinder inside and outside the reactor near the stirring paddle part is provided with a pressure sensing point, which can monitor the stirring paddle pressure difference, so as to monitor the acid and hydrocarbon emulsion mixing condition, and the current can also directly reflect the acid and hydrocarbon mixing ratio. When the ratio between acid and hydrocarbon decreases, the current will decrease. If the stirring paddle differential pressure is low, it may be caused by stirring paddle wear or low acid to hydrocarbon ratio. If the current or stirring paddle differential pressure drops sharply, it is most likely that the stirring paddle is damaged, causing the reaction emulsion to short circuit, that is, the guide cylinder inside and outside is connected. If the stirring paddle is damaged, it will cause rotor imbalance and also cause sealing leakage. The pressure sensing pipe should be cleaned regularly with reaction effluent for flushing once a week to remove the coking formed during the reaction and ensure accurate readings.

[0075] Control of stable process operation and feed components: large process operation fluctuation will cause alternating load of stirring paddle, and when starting the stirrer, the stirring medium is acid hydrocarbon mixture, the motor is started instantaneously, the shaft bearing bears huge torque, which will impact the seal. In production, a loud noise is produced at the stirring paddle when starting the motor instantaneously, which again confirms that the specific gravity of acid hydrocarbon mixture increases, and the impact of instantaneous motor starting on the stirring paddle and seal. The acid should be slowly dropped to avoid uneven distribution of acid causing excessive stirring torque, and the motor should be started when the amount of dropped acid is not more than 60% of the normal production acid, which can minimize the impact on the stirring paddle. When the feed is composed of C3, C4 and C5 olefins, these different olefin feeds can react to generate compounds of different product quality, and the acid consumption is also different, which causes the density of emulsion in the alkylation reactor to be different, and the long-term alternating torque of the stirring paddle causes stress concentration and fatigue damage, and in severe cases, the seal may leak or the stirring paddle may crack. Therefore, while optimizing the operation, the feed components should also be stabilized, and the feed components should be regularly detected to ensure that the standard is met. To a certain extent, seal leakage can also be avoided to cause accidents.

[0076] Two existing reactors are taken as examples and are denoted as A and B for comparison, and the measured operating parameters are shown in the following table:

[0077]

[0078]

[0079] Two reactors are taken as examples and are denoted as C and D, and the reactors are both provided with the seal and system provided by the application, and the flushing process is controlled by the above method, and the measured operating parameters are shown in the following table:

[0080]

[0081] It can be seen that, compared with the prior art, after improvement, optimization and adjustment of the seal, system and flushing method provided by the application, the main operating parameters of the reactor, such as vibration, bearing temperature, seal heat generation, emulsification effect of acid hydrocarbon mixture, etc. have been greatly improved. In particular, after the seal is improved, no seal oil leaks, and the environmental protection goal of zero leakage of the reactor seal is completely achieved.

[0082] Through actual inspection, the method and system can make the two reactors of the alkylation device run for nearly 25 months before the overhaul, and no shutdown event caused by seal failure occurs during the period. The goal of "zero leakage" and safe and stable long-period operation of the reactor of the alkylation device is achieved. Compared with the same type of device reactor seal, the number of maintenance times is reduced by at least 4 times in 2 years, and the cumulative non-scheduled shutdown and maintenance time is about 16-18 days, which saves the maintenance cost, ensures the safe and environmentally friendly long-period operation, and greatly improves the economic benefit.

[0083] According to the calculation of the processing capacity loss of the single alkylating device reactor maintenance, the processing capacity of the single alkylating device is about 10-12t / h less than that of the two simultaneously running alkylating devices, and the maintenance time of each reactor is at least 6d, including 4d of isolation replacement and 2d of maintenance. Therefore, the processing capacity loss of each reactor is about 6d*24h*10t / h=1440t. The raw material of the alkylating device is liquefied gas, and the octane number of the alkylated product oil is generally about 97. According to the difference between the 95# gasoline delivery price and the liquefied gas price, the processing capacity benefit loss of each reactor is at least 3.42 million yuan. According to the calculation of the annual maintenance of the imported seal of the alkylating reactor of the same device, at least two maintenance times of the alkylating reactor are effectively avoided in nearly one year. According to the calculation of the benefit loss of the single reactor single maintenance, the cumulative benefit is about 6.84 million yuan in nearly one year. It can be seen that the present scheme has huge economic benefits.

[0084] The above only describes the preferred embodiments of the present application, and does not use any restriction on the technical solutions of the present application. Those skilled in the art should understand that the technical solutions can be simply modified and replaced without departing from the spirit and principles of the present application, and these modifications and replacements also belong to the protection scope covered by the claims.

Claims

1. A sulfuric acid alkylation reactor seal, characterized by, The shaft sleeve (6) is sleeved outside the shaft, and the shaft sleeve (6) is sequentially connected in series from the medium side to the atmosphere side with the protective sleeve (1), the auxiliary shaft sleeve (4), the primary seal (5), the self-aligning roller bearing (9), the secondary seal (10), the throttle ring (12) and the wedge-shaped shaft holder (11); The primary seal (5) comprises a sealing medium side moving ring (13), and the sealing medium side moving ring (13) is connected with a sealing medium side static ring (14); the auxiliary shaft sleeve (4) is arranged between the protective sleeve (1) and the sealing medium side moving ring (13), and is used for adjusting the balance diameter of the sealing medium side moving ring (13); the difference between the end-to-end face inner diameter of the sealing medium side moving ring (13) and the sealing medium side static ring (14) and the outer diameter of the shaft sleeve (6) is 6mm±0.5mm; the difference between the end-to-end face outer diameter of the sealing medium side moving ring (13) and the sealing medium side static ring (14) and the outer diameter of the shaft sleeve (6) is 16mm±0.5mm; the difference between the balance diameter of the sealing medium side moving ring (13) and the outer diameter of the shaft sleeve (6) is 8mm±0.5mm; The secondary seal (10) comprises a sealing atmosphere side moving ring (15), and the sealing atmosphere side moving ring (15) is connected with a sealing atmosphere side static ring (16); a groove is arranged on the shaft sleeve (6) at a position corresponding to the secondary seal (10), and is used for adjusting the balance diameter of the sealing atmosphere side moving ring (15); the difference between the end-to-end face outer diameter of the sealing atmosphere side moving ring (15) and the sealing atmosphere side static ring (16) and the outer diameter of the shaft sleeve (6) is 8mm±0.5mm; the difference between the end-to-end face inner diameter of the sealing atmosphere side moving ring (15) and the sealing atmosphere side static ring (16) and the outer diameter of the shaft sleeve (6) is -3mm±0.5mm; the difference between the balance diameter of the sealing atmosphere side moving ring (15) and the outer diameter of the shaft sleeve (6) is 0mm.

2. The sulfuric acid alkylation reactor seal of claim 1, wherein, The material of the sealing atmosphere side moving ring (15) is graphite.

3. The sulfuric acid alkylation reactor seal of claim 1, wherein, The self-aligning roller bearing (9) is limited by the round nut (7).

4. The sulfuric acid alkylation reactor seal of claim 3, wherein, A stop washer (8) is arranged between the self-aligning roller bearing (9) and the round nut (7).

5. The sulfuric acid alkylation reactor seal of any of claims 1-4, wherein, The materials of the sealing medium side moving ring (13) and the sealing medium side static ring (14) are both pressureless sintered silicon carbide.

6. A flushing system comprising the seal of the sulfuric acid alkylation reactor of any of claims 1-5, wherein, An oil tank (20) is arranged inside the oil tank (20), and an oil pump (21) is arranged inside the oil tank (20); the outlet of the oil pump (21) is connected with the atmosphere side flushing medium inlet of a reactor seal (22), the atmosphere side flushing medium outlet of the reactor seal (22) is connected with the inlet of the oil tank (20); the outlet of the oil pump (21) is also connected with an energy storage tank (23); the medium side flushing inlet of the reactor seal (22) is connected with a reactor.

7. The sulfuric acid alkylation reactor seal flush system of claim 6, wherein, The inlet of the oil pump (21) is connected with a filter (24).

8. The sulfuric acid alkylation reactor flush system of claim 6, wherein, An adjusting valve (25) is arranged between the atmosphere side flushing medium outlet of the reactor seal (22) and the inlet of the oil tank (20).

9. The sulfuric acid alkylation reactor flush system of claim 8, wherein, A pressure gauge (26) and a second ball valve (27) are arranged between the adjusting valve (25) and the atmosphere side flushing medium outlet of the reactor seal (22).

10. A method of rinsing using the rinsing system according to any one of claims 6-9, characterized in that, The following steps are included: The pressure of the air bag inside the energy storage tank (23) is higher than the target pressure of the atmosphere side flushing liquid by 0.05MPa-0.1MPa; The liquid level of the flushing medium on the atmosphere side inside the oil tank (20) accounts for 65% to 85% of the volume of the oil tank (20); The oil pump (21) is started, and the pressure of the oil pump (21) is adjusted so that the pressure of the flushing medium on the atmosphere side is higher than the pressure of the flushing medium on the medium side by 0.14 MPa to 0.41 MPa; The flushing on the medium side is started, and the pressure of the flushing medium on the medium side before entering the reactor seal (22) is higher than the pressure inside the reactor by 0.15 MPa to 0.35 MPa; After the pressure of the oil pump (21) and the pressure of the flushing medium on the medium side are adjusted, the reactor is fed until the pressure inside the reactor reaches the normal production pressure; After the pressure inside the reactor reaches the normal production pressure, the pressure of the oil pump (21) is adjusted to the target pressure of the flushing medium on the atmosphere side, the flushing medium on the atmosphere side enters the internal cavity of the seal, and after a liquid film is formed between the sealing atmosphere side moving ring (15) and the sealing atmosphere side static ring (16), it returns to the oil tank (20); the pressure of the flushing medium on the medium side is adjusted to the target pressure of the flushing medium on the medium side, and the flushing medium on the medium side enters the internal cavity of the seal, and a liquid film is formed between the sealing medium side moving ring (13) and the sealing medium side static ring (14); After the pressure of the oil pump (21) and the pressure of the flushing medium on the atmosphere side are adjusted to the target pressure, it is checked whether there is leakage at each sealing point; After confirming that there is no leakage at each sealing point, the stirring motor is started to run, and the production is entered; After the production is completed, the stirring motor is turned off, the pressure inside the reactor is released and replaced, the sealing medium side flushing is stopped first, and then the sealing atmosphere side flushing is stopped, and the sealing flushing is completed.

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