Online weighing continuous differential self-adding instrument for catalytic cracking unit assistant

Abstract

The utility model relates to an on-line weighing continuous differential self-adding instrument for catalytic cracking unit auxiliaries, and belongs to the technical field of petrochemical engineering. Comprising a precise dust remover, an auxiliary storage tank, a weighing differential feeder, a negative pressure ejector and a DCS (Distributed Control System) automatic control system, the precise dust remover is mounted at the top of the additive storage tank, the additive storage tank is connected with the weighing differential feeder, and the weighing differential feeder is connected with the negative pressure ejector; and the DCS automatic control system is respectively connected with the precise dust remover, the additive storage tank, the weighing differential feeder and the negative pressure ejector. According to the on-line weighing continuous differential self-adding instrument for the catalytic cracking unit assistant, disclosed by the utility model, after the negative pressure ejector converts a high-back-pressure cavity of the ejector into micro negative pressure (-0.01 to-0.05 MPa) through an ingenious gas circuit structure design, continuous differential feeding is performed to the negative pressure ejector, and then the assistant is conveyed to a regenerator through compressed air. A more accurate and stable additive adding scheme is provided for the catalytic cracking process, and the technical progress and industrial upgrading of related industries are promoted.

Description

Technical Field

[0001] The utility model relates to an online weighing continuous differential self-adding instrument for additives in a catalytic cracking unit. The instrument weighs the additives in the catalytic cracking unit in real time online and continuously differentially feeds the additives to a reverse regeneration system under a back pressure (0.4-0.6MPa). The instrument is mainly used for catalytic cracking units in petrochemical enterprises and belongs to the technical field of petrochemical industry. Background Art

[0002] At present, the combustion aids and desulfurization and denitrification additives of the catalytic cracking units of domestic refineries are usually added to the regenerator in an intermittent manner. Since the amount and time of the combustion aid added are unstable, it cannot be continuously added to the regenerator, which affects the charring effect of the regenerator, and also affects the efficiency of desulfurization and denitrification, which is not conducive to the overall stable operation of the unit, and at the same time, reduces the working efficiency of the unit and may also increase the risk of environmental pollution.

[0003] Therefore, an online weighing continuous differential self-adding instrument for catalytic cracking unit additives is provided to realize continuous and accurate feeding to the negative pressure injector. The negative pressure injector converts the high back pressure inside the injector into negative pressure through the adjustment of compressed air. The additives and compressed air are mixed in the negative pressure accelerator to form a stable flow state, and then are evenly injected into the regenerator to ensure that the additives are evenly distributed in the entire regenerator, thereby solving the problems of traditional intermittent feeding, uneven addition of combustion aids affecting the regenerator burning effect, and unstable addition of other additives when adding adverse effects on the operation of the device, which have become technical problems that urgently need to be solved in this technical field. Utility Model Content

[0004] The utility model aims to provide an online weighing continuous differential self-adding instrument system for catalytic cracking additives, so as to realize accurate, continuous and automatic addition of additives in the catalytic cracking process, so as to improve the efficiency and product quality of the catalytic cracking process. The additives of the catalytic cracking unit are fed through a weighing differential feeding device, and the accurate metering of trace additives can be realized by weighing by reduction. Then, the delivery speed of the additives is controlled by adjusting the frequency of the weighing differential feeder device, so as to realize continuous and accurate feeding to a negative pressure ejector. The negative pressure ejector is regulated by compressed air, and the high back pressure in the ejector is converted into negative pressure. The additives are mixed with the compressed air in the negative pressure accelerator to form a stable flow state, and then are uniformly injected into the regenerator; ensuring uniform distribution of the additives in the entire regenerator, so as to solve the problem of the interval feeding in the traditional way, which makes the uneven addition of the combustion aid affect the charring effect of the regenerator, and the adverse effect of the instability of the addition of other additives on the operation of the device, and is one of the technical means to improve the refined operation of the reaction-regeneration system.

[0005] The above-mentioned purpose of the utility model is achieved through the following technical solutions:

[0006] An online weighing continuous differential self-adding instrument for additives in a catalytic cracking unit is characterized by comprising a precision dust collector, an additive storage tank, a weighing differential feeder, a negative pressure ejector, and a DCS automatic control system; the precision dust collector is installed on the top of the additive storage tank, the additive storage tank is connected to the weighing differential feeder, and the weighing differential feeder is connected to the negative pressure ejector; the DCS automatic control system is respectively connected to the precision dust collector, the additive storage tank, the weighing differential feeder, and the negative pressure ejector.

[0007] Preferably, the weighing differential feeder includes a first feed valve, an exhaust valve, a weighing differential feeder silo, a weighing sensor, a variable frequency speed regulating motor, and a fine feeding valve; wherein the first feed valve is connected to the inlet of the differential feeding silo via a metal flexible connection, the exhaust valve is arranged at the upper part of the differential feeding silo, the exhaust valve is connected to the upper part of the additive storage tank via a metal flexible connection, the bottom of the differential feeding silo is connected to the upper part of the fine feeding valve, the variable frequency speed regulating motor is connected to one side of the fine feeding valve, and the end of the fine feeding valve is connected to the discharge port via a metal flexible connection.

[0008] Preferably, three groups of weighing sensors are evenly arranged under the cone of the weighing differential feeder silo.

[0009] Preferably, the negative pressure injector includes a second feed valve, an air intake valve, a negative pressure injector cavity, a gas acceleration injector, an acceleration injector, and a cut-off valve; one end of the second feed valve is connected to the discharge port of the weighing differential feeder, and the other end of the second feed valve is connected to the feed port of the negative pressure injector cavity, one end of the air intake valve is connected to the air intake pipe, and the other end of the air intake valve is connected to the feed pipeline of the negative pressure injector, and another end of the air intake valve is connected to the gas acceleration injector in the negative pressure injector, the gas acceleration injector is installed at one end of the negative pressure injector cavity, and the acceleration injector is installed at the other end of the negative pressure injector cavity, the outlet of the acceleration injector is connected to one end of the cut-off valve, and the other end of the cut-off valve is connected to the anti-re-system.

[0010] Preferably, the lower discharge port of the auxiliary agent storage tank is connected to the first feed valve in the weighing differential feeder via a metal flexible connection;

[0011] Preferably, the upper portion of the auxiliary agent storage tank is connected to the exhaust valve in the weighing differential feeder via a metal flexible connection.

[0012] Preferably, the discharge port of the fine feed valve is connected to the second feed valve of the negative pressure ejector via a metal flexible connection.

[0013] Beneficial effects:

[0014] The utility model is an online weighing continuous differential self-adding instrument for additives in a catalytic cracking unit. Starting from the additive storage tank, the additive is weighed by a weighing differential feeder and sent to a negative pressure injector. The negative pressure injector is cleverly designed with a gas path structure. After the high back pressure cavity of the injector is converted into a slight negative pressure (-0.01 to -0.05MPa), the additive is continuously differentially fed to the negative pressure injector, and then the additive is transported to the regenerator by compressed air. The utility model provides a more accurate and stable additive dosing solution for the catalytic cracking process, which is helpful to promote technological progress and industrial upgrading in related industries.

[0015] The present invention will be further described below in conjunction with the accompanying drawings and specific implementations, but this does not necessarily limit the scope of protection of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the online weighing continuous differential self-adding instrument used for catalytic cracking unit additives in Example 1 of the utility model.

[0017] Figure 2 It is a structural schematic diagram of a weighing differential feeder in an online weighing continuous differential self-adding instrument for additives in a catalytic cracking unit in Example 1 of the utility model.

[0018] Figure 3 It is a schematic diagram of the structure of the negative pressure ejector in the online weighing continuous differential self-adding instrument for catalytic cracking unit additives in Example 1 of the utility model.

[0019] Names of main parts in the attached figure:

[0020] 1Precision dust collector 2Additive storage tank

[0021] 3Weighing differential feeder 4Negative pressure ejector

[0022] 5DCS automatic control system

[0023] 3. Weighing differential feeder

[0024] 3-1 First feed valve 3-2 Exhaust valve

[0025] 3-3 weighing differential feeder silo 3-4 weighing sensor

[0026] 3-5 variable frequency speed regulating motor 3-6 fine feed valve

[0027] 4-1 Second feed valve 4-2 Air intake valve

[0028] 4-3 Negative pressure ejector cavity 4-4 Cut-off valve

[0029] 4-5 Gas Accelerator Injector 4-6 Accelerator Injector DETAILED DESCRIPTION

[0030] Unless otherwise specified, in the following embodiments, the components used are conventional components available on the market in this technical field; the equipment not described in detail is equipment that can be purchased on the market, and the control systems used are conventional control systems in this technical field; the connections between the components are conventional connections.

[0031] Example 1

[0032] like Figure 1 As shown, it is a schematic diagram of the structure of the online weighing continuous differential self-adding instrument for catalytic cracking unit additives in Example 1 of the utility model; Figure 2 As shown, the structural schematic diagram of the weighing differential feeder in the online weighing continuous differential self-adding instrument for catalytic cracking unit additives in Example 1 of the utility model; Figure 3 As shown, it is a schematic diagram of the structure of the negative pressure ejector in the online weighing continuous differential self-adding instrument for catalytic cracking unit additives in Example 1 of the utility model; wherein: 1 is a precision dust collector, 2 is an additive storage tank, 3 is a weighing differential feeder, 4 is a negative pressure ejector, 5 is a DCS automatic control system, 3-1 is a first feed valve, 3-2 is an exhaust valve, 3-3 is a weighing differential feeder silo, 3-4 is a weighing sensor, 3-5 is a variable frequency speed regulating motor, 3-6 is a precision feed valve, 4-1 is a second feed valve, 4-2 is an intake valve, 4-3 is a negative pressure ejector cavity, 4-4 is a cut-off valve, 4-5 is a gas acceleration ejector, and 4-6 is an acceleration ejector;

[0033] The utility model discloses an online weighing continuous differential self-adding instrument for additives of a catalytic cracking unit, comprising: a precision dust collector 1, an additive storage tank 2, a weighing differential feeder 3, a negative pressure ejector 4, a DCS automatic control system 5, a first feed valve 3-1, an exhaust valve 3-2, a weighing differential feeder bin 3-3, a weighing sensor 3-4, a variable frequency speed regulating motor 3-5, a precision feeder valve 3-6, a second feed valve 4-1, an air intake valve 4-2, a negative pressure ejector cavity 4-3, a cut-off valve 4-4, a gas acceleration ejector 4-5, and an acceleration ejector 4-6; the precision dust collector 1 is installed on the top of the additive storage tank 2, the additive storage tank 2 is connected to the weighing differential feeder 3, and the weighing differential feeder 3 is connected to the negative pressure ejector 4; the DCS automatic control system 5 is respectively connected to the precision dust collector 1, the additive storage tank 2, the weighing differential feeder 3, and the negative pressure ejector 4;

[0034] Specifically, the lower discharge port of the auxiliary agent storage tank 2 is connected to the first feed valve 3-1 in the weighing differential feeder 3 via a metal flexible connection; the upper part of the auxiliary agent storage tank 2 is connected to the exhaust valve 3-2 in the weighing differential feeder 3 via a metal flexible connection;

[0035] The dust-laden gas during unloading passes through the top of the auxiliary agent storage tank 2 and enters the precision dust collector 1 for dust removal;

[0036] The weighing differential feeder 3 comprises: a first feed valve 3-1, an exhaust valve 3-2, a weighing differential feeder bin 3-3, a weighing sensor 3-4, a variable frequency speed regulating motor 3-5, and a precision feeder valve 3-6; wherein the first feed valve 3-1 is connected to the feed inlet of the differential feeder bin 3-3 via a metal flexible connection, three groups of weighing sensors 3-4 are arranged evenly under the cone of the weighing differential feeder bin 3-3, and the exhaust valve 3-2 is arranged at the upper part of the weighing differential feeder bin 3-3, and the exhaust valve 3-2 is connected to the feed inlet of the differential feeder bin 3-3 via a metal flexible connection. The upper part of the auxiliary agent storage tank 2 is connected via a metal flexible connection, the bottom of the weighing differential feeder silo 3-3 is connected to the upper part of the fine feeding valve 3-6, the variable frequency speed regulating motor 3-5 is connected to one side of the fine feeding valve 3-6, the end of the fine feeding valve 3-6 is connected to the discharge port via a metal flexible connection, and the discharge port of the fine feeding valve 3-6 is connected to the second feed valve 4-1 of the negative pressure ejector 4 via a metal flexible connection; the weighing sensor 3-4 in the weighing differential feeder 3 weighs the auxiliary agent in the weighing differential feeder silo 3-3;

[0037] The negative pressure injector 4 includes: a second feed valve 4-1, an air intake valve 4-2, a negative pressure injector cavity 4-3, a gas acceleration injector 4-5, an acceleration injector 4-6, and a cut-off valve 4-4; one end of the second feed valve 4-1 is connected to the discharge port of the weighing differential feeder 3, the other end of the second feed valve 4-1 is connected to the feed port of the negative pressure injector cavity 4-3, one end of the air intake valve 4-2 is connected to the air intake pipe, the other end of the air intake valve 4-2 is connected to the feed pipeline of the negative pressure injector 4, and another end of the air intake valve 4-2 is connected to the gas acceleration injector 4-5 in the negative pressure injector 4, the gas acceleration injector 4-5 is installed at one end of the negative pressure injector cavity 4-3, the acceleration injector 4-6 is installed at the other end of the negative pressure injector cavity 4-3, the outlet of the acceleration injector 4-6 is connected to one end of the cut-off valve 4-4, and the other end of the cut-off valve 4-4 is connected to the anti-re-system.

[0038] The operation steps of the online weighing continuous differential self-adding instrument for catalytic cracking unit additives of the utility model are as follows:

[0039] When adding additives, since the catalytic cracking unit has a reverse pressure of 0.4-0.6Mpa in the regeneration system, the negative pressure ejector 4 must be adjusted first to form a negative pressure in the feed bin. First, open the cut-off valve 4-4 and at the same time, open the air inlet valve 4-2. The pressure of the compressed air entering this way is greater than the pressure of the regeneration system. At this time, one way of compressed air enters the feed inlet pipeline of the negative pressure ejector 4 from the top, and the other way of compressed air is gathered through the throat diameter of the air inlet pipeline of the negative pressure ejector 4 and then diffused and ejected, so that the compressed air injection speed is greater than the pressure and speed of the regeneration system, thereby generating a pressure difference and making the negative pressure Negative pressure (-0.01~-0.05MPa) is formed in the ejector cavity. After adjustment, the ejector in the ejector storage tank 2 flows into the weighing differential feeder silo through the first feed valve 3-1 by gravity, and the weighing sensor starts to weigh the silo. The ejector is then fed through the second feed valve 4-1 through the fine feed valve 3-6 at the operating frequency set by the variable frequency speed regulating motor 3-5 and enters the negative pressure ejector cavity 4-3 evenly. Under the action of negative pressure, the ejector is mixed with the gas entering through the air inlet valve 4-2 in the negative pressure ejector cavity 4-3, and is continuously and evenly delivered to the recycling system through the cut-off valve 4-4.

[0040] The operation mechanism of the weighing differential feeder 3: the additive in the storage tank enters the weighing differential feeder silo 3-3, and the three groups of weighing sensors 3-4 provided in the weighing differential feeder silo 3-3 measure the additive in the weighing differential feeder silo 3-3 in real time. The fine feeding valve 3-6 is driven to operate by adjusting the variable frequency speed regulating motor 3-5. The feeding weight is fed back to the DCS automatic control system 5 through the signal of the weighing sensor 3-4, and the summary calculation is performed to obtain the feeding amount in a certain period of time. According to the process requirements, the operating frequency of the variable frequency speed regulating motor 3-5 is adjusted to achieve the feeding amount required by the process. An exhaust valve 3-2 is provided on the upper part of the weighing differential feeder silo 3-3. The dust-containing gas enters the additive storage tank 2 and the top through the exhaust valve 3-2 and the pipeline and is discharged through the precision dust collector 1;

[0041] The operating mechanism of the negative pressure ejector 4 is as follows: open the shut-off valve 4-4 at the ejector outlet, and at the same time, open the air inlet valve 4-2, so that one path of compressed air goes upward into the discharge pipeline of the negative pressure ejector 4, and the other path of compressed air is gathered and then diffused and ejected through the throat diameter of the air inlet pipeline of the negative pressure ejector 4 (accelerating ejector 4-5), so that the injection speed of the compressed air is greater than the speed of the return pressure of the recombination system, thereby generating a pressure difference, so that a negative pressure is formed at the discharge port of the negative pressure ejector 4, and then open the second feed valve 4-1 to evenly deliver it to the negative pressure ejector 4. Under the action of negative pressure, the auxiliary agent enters the negative pressure ejector 4 by its own weight, and then mixes with the first air inlet line, and the auxiliary agent is evenly delivered to the recombination system through the shut-off valve 4-4.

[0042] According to the hardware of the utility model, on the basis of the existing DCS automatic control system, the DCS automatic control system 5 of the utility model can be obtained by using conventional software; the innovation point of the utility model lies in the hardware; the DCS automatic control system 5 of the utility model is weighed and measured online by the program of the programmable controller, and continuously differentially feeds the material to the recirculation system. The whole operation can be automated, and the parameters can be changed according to the process optimization requirements to realize the switching between automatic and manual operations, thereby improving the automation level of dosing.

[0043] The utility model is an online weighing continuous differential self-feeding instrument for additives in a catalytic cracking unit. It relies on a weighing differential feeder to weigh and send the additives to a negative pressure injector. The negative pressure injector is cleverly designed with a gas path structure to convert the high back pressure cavity of the injector into a slight negative pressure (-0.01 to -0.05 MPa). The complete process is then carried out through continuous differential feeding of compressed air to a reverse regeneration system. The entire process is free of dust leakage, which solves the problems of temperature runaway, desulfurization and sulfur-nitration effects in the intermittent feeding of the catalytic cracking unit, and helps to improve the refined operation level of the catalytic unit.

[0044] The above is only a preferred specific implementation method of the utility model, but the protection scope of the utility model is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the utility model, according to the technical scheme and utility model concept of the utility model, shall be covered by the protection scope of the utility model.

Claims

1. An online weighing continuous differential self-adding instrument for catalytic cracking unit additives, characterized in that: It includes a precision dust collector, an additive storage tank, a weighing differential feeder, a negative pressure ejector, and a DCS automatic control system; the precision dust collector is installed on the top of the additive storage tank, the additive storage tank is connected to the weighing differential feeder, and the weighing differential feeder is connected to the negative pressure ejector; the DCS automatic control system is respectively connected to the precision dust collector, the additive storage tank, the weighing differential feeder, and the negative pressure ejector.

2. The online weighing continuous differential self-adding instrument for catalytic cracking unit additive according to claim 1, characterized in that: The weighing differential feeder includes a first feed valve, an exhaust valve, a weighing differential feeder silo, a weighing sensor, a variable frequency speed regulating motor, and a fine feeding valve; wherein the first feed valve is connected to the feed inlet of the differential feeding silo via a metal flexible connection, the exhaust valve is arranged at the upper part of the differential feeding silo, the exhaust valve is connected to the upper part of the auxiliary agent storage tank via a metal flexible connection, the bottom of the differential feeding silo is connected to the upper part of the fine feeding valve, the variable frequency speed regulating motor is connected to one side of the fine feeding valve, and the end of the fine feeding valve is connected to the discharge port via a metal flexible connection.

3. The online weighing continuous differential self-adding instrument for catalytic cracking unit additive according to claim 2, characterized in that: Three groups of weighing sensors are evenly arranged under the cone of the weighing differential feeder bin.

4. The online weighing continuous differential self-adding instrument for catalytic cracking unit additive according to claim 3, characterized in that: The negative pressure injector comprises a second feed valve, an air intake valve, a negative pressure injector cavity, a gas acceleration injector, an acceleration injector and a cut-off valve; one end of the second feed valve is connected to the discharge port of the weighing differential feeder, the other end of the second feed valve is connected to the feed port of the negative pressure injector cavity, one end of the air intake valve is connected to the air intake pipe, the other end of the air intake valve is connected to the feed pipeline of the negative pressure injector, another end of the air intake valve is connected to the gas acceleration injector in the negative pressure injector, the gas acceleration injector is installed at one end of the negative pressure injector cavity, the acceleration injector is installed at the other end of the negative pressure injector cavity, the outlet of the acceleration injector is connected to one end of the cut-off valve, and the other end of the cut-off valve is connected to the anti-recharge system.

5. The online weighing continuous differential self-adding instrument for catalytic cracking unit additive according to claim 4, characterized in that: The lower discharge port of the auxiliary agent storage tank is connected to the first feed valve in the weighing differential feeder via a metal flexible connection.

6. The online weighing continuous differential self-adding instrument for catalytic cracking unit additive according to claim 5, characterized in that: The upper part of the auxiliary agent storage tank is connected to the exhaust valve in the weighing differential feeder via a metal flexible connection.

7. The online weighing continuous differential self-adding instrument for catalytic cracking unit additives according to claim 6, characterized in that: The discharge port of the fine feed valve is connected to the second feed valve of the negative pressure ejector via a metal flexible connection.

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