Closed automatic operation system for ionic liquid alkylation active agent

Abstract

The invention discloses an ionic liquid alkylation active agent closed automatic operation system which comprises a PLC or DCS control device, a weighing sensor, a pressure feed tank, a stock bin, a first delivery valve, an isolation tank, a second delivery valve and a reaction kettle, and an upper outlet of the stock bin is provided with a cyclone separator, a bag-type dust collector and an alkali washing dust collector; the pressure feed tank is arranged on the ground; the weighing sensor is arranged below the isolation tank, pressurized dry nitrogen for conveying an active agent is arranged in the pressure feed tank, and the active agent is conveyed to the stock bin in a pressure feed mode; the active agent automatically flows from the stock bin or is pressed into the isolation tank, and the active agent is pressed into the reaction kettle after being received and weighed by the isolation tank to a target value. The method has the beneficial effects that the operation is simple, the filling efficiency is high, closed filling can be realized, and active components are prevented from drifting away; the contact between the active components and air in the filling process can be reduced; an alkali washing process is added at the outlet of the dust remover to prevent acidic substances from polluting the environment, realize continuous and stable filling and reduce the operation intensity.

Description

Technical Field

[0001] The invention relates to the field of petrochemical industry, and in particular to a closed automatic operation system for an ionic liquid alkylation activator. Background Art

[0002] The ionic liquid alkylation technology uses isobutane and butene as raw materials and chloroaluminate ionic liquid as catalyst to synthesize alkylate oil. The technology is novel and the process principle is complex. There are only 6 industrial units in China.

[0003] The activity of ionic liquid is characterized by the activity index. As impurities are introduced during the reaction, the activity of the ionic liquid gradually decays. When the activity index is lower than 1.1, it is very easy to cause incomplete conversion of butene during the reaction, olefins in the reactor outlet stream, olefins dissolving in the ionic liquid, a vicious cycle, ionic liquid loss, and subsequent unit acid and salt corrosion. The alkylation quality is unqualified and a series of serious problems.

[0004] In order to maintain the activity, the ionic liquid alkylation unit is equipped with a special ionic liquid regeneration system to continuously replenish activators such as chloroaluminate and copper chloride. The activator is a solid particle powder with a particle size ranging from 30 to 600μm, irregular particle shape, bulk density of 1800kg / m3, and extremely poor fluidity. The chloroaluminate and copper chloride components contained in the activator are hazardous chemicals and are highly irritating to the human respiratory tract, eyes, skin, etc. When in contact with water or water vapor, a strong exothermic reaction will occur, and even explosion, to generate hydrochloric acid.

[0005] The solubility of the active agent in the ionic liquid is between 2.5 and 5 w%. The circulation volume of the ionic liquid used for regeneration is 4 to 5 t / h, and the total ionic liquid storage of the system is 260 t. For every 0.1 decrease in the activity index, the entire system needs to replenish more than ten tons of active agent. In view of the above process constraints, the replenishment of the active agent needs to be fully automatic and continuous or nearly continuous, and must be accurately measured.

[0006] Currently, the surfactant is loaded into the storage tank by unpacking ton bags. The filling process is poorly sealed, which has a great impact on personnel and the environment. The surfactant has poor fluidity, and some intermediate transmissions are unstable, making continuous replenishment impossible. The surfactant has a large accumulation angle and is sticky, making it impossible to monitor the material level. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a closed charging system for an ionic liquid active agent, reduce the impact on personnel and the environment, realize continuous and stable filling of the active agent into the ionic liquid regeneration system, and accurately measure the amount of the active agent. The activity of the ionic liquid system is stable and controllable through the filling amount, and the solid content meets the operation requirements of the device, avoiding the phenomenon of reaction delay and pipeline blockage, greatly reducing the operating intensity, and improving the safety, stability and environmental protection of the device operation.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: an ionic liquid alkylation active agent closed automatic operation system, including: a PLC or DCS control device, a weighing sensor, the PLC or DCS control device controls the automatic feeding in sequence, and also includes a pressure feeding tank, a silo, a first delivery valve, an isolation tank, a second delivery valve and a reactor connected in sequence, the upper outlet of the silo is provided with a cyclone separator, a bag dust collector and an alkali washing dust collector; the pressure feeding tank is arranged on the ground; the weighing sensor is arranged below the isolation tank; the pressure feeding tank is provided with a pressurized drying system for conveying the active agent Nitrogen, the delivery pressure of the pressurized dry nitrogen is 0.2~0.5MPa(G), and the active agent is delivered to the silo by pressure; the active agent flows from the silo to the isolation tank by gravity or pressure, and when the isolation tank receives the material and weighs it to the target value, the first delivery valve is closed; at this time, the charging solenoid valve of the isolation tank fills nitrogen into the isolation tank, and when the isolation tank is pressurized to 0.1~0.5MPa(G), the second delivery valve is opened, and the active agent is pressurized to the reactor, and then the second delivery valve and the isolation tank charging valve are closed, and the isolation tank pressure relief valve is opened to relieve the pressure of the isolation tank, and the above-mentioned feeding process is repeated to achieve continuous and stable operation.

[0009] The pressure tanks are several independent pressure tanks with cylindrical cone bottoms, each with a capacity of 2 to 3 m 3 , pressure resistance level 1.0MPa(G), nitrogen consumption per pressure tank 200~300Nm 3 / h.

[0010] The active agent is solid particle powder with a particle size of 30 to 600 μm.

[0011] The dry nitrogen is used as the conveying gas, and the pressure of the dry nitrogen is ≥0.5MPa(G).

[0012] The active agent enters the silo tangentially along the tank wall.

[0013] The isolation tank has a volume of 0.1 to 0.2 m 3 , cylindrical cone bottom.

[0014] The beneficial effects of the present invention are as follows: the present technology adopts an advanced nitrogen fluidization method, which is simple to operate and has a higher filling efficiency. It can realize closed filling, avoid the active components from being dispersed, and reduce the contact between the active components and the air during the filling process to avoid moisture absorption. An alkali washing process is added to the dust collector outlet to avoid acidic substances from polluting the environment. It can realize continuous and stable filling of the ionic liquid alkylation active agent to the ionic liquid regeneration system, accurate metering, stable and controllable activity of the ionic liquid system, and the solid content meets the device operation requirements, which greatly reduces the operation intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the closed automatic operation system of the ionic liquid alkylation active agent;

[0016] Figure 2 This is a schematic diagram of the closed and automated operation status of the ionic liquid alkylation activator.

[0017] In the figure:

[0018] 1. Pressure tank 2. Silo 3. First delivery valve

[0019] 4. Isolation tank 5. Weighing sensor 6. Second delivery valve

[0020] 7. Reactor 8. Cyclone separator 9. Bag dust collector

[0021] 10. Alkaline dust collector 11. Isolation tank charging valve

[0022] 12. Isolation tank pressure relief valve DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0024] like Figure 1 , Figure 2 As shown, the closed automatic operation system of the ionic liquid alkylation activator of the present invention comprises a pressure delivery tank 1, a silo 2, a first delivery valve 3, an isolation tank 4, a weighing sensor 5, a second delivery valve 6, a reactor 7, a cyclone separator 8, a bag filter 9, an alkali cleaning dust collector 10, an isolation tank charging valve 11, an isolation tank pressure relief valve 12 and a PLC or DCS control system, wherein the DCS is a Honeywell PKS system, and the valve adopts a butterfly valve of DN20 to 200 according to the pipe diameter.

[0025] The active agent is conveyed from the pressure tank 1 to the silo 2 in a dilute phase after being pressurized with nitrogen. The conveying pressure is 0.2-0.5MPa(G) and the nitrogen consumption is about 200-300Nm3 / h. The tail gas at the top of the silo 2 is purified by the cyclone separator 8, the bag dust collector 9 and the alkali dust collector 10 and then discharged. The powder separated by the cyclone separator 8 is returned to the silo 2.

[0026] After the active agent reaches the silo 2, under the premise that the weighing sensor is 0, the DCS controller sends a signal to open the first delivery valve 3, and the active component flows into the isolation tank 4 through the first delivery valve 3. The sensor 5 set at the bottom of the isolation tank starts to weigh. After reaching the target value, the DCS sends a signal to close the first unloading valve 3. The first unloading valve 3 is closed after receiving the signal. The DCS sends a signal to open the charging valve 11. The isolation tank charging valve opens after receiving the signal. The isolation tank 4 is pressurized by the pressure of the low-pressure nitrogen pipeline network. After the pressure of the isolation tank is pressurized to be greater than 0.1MPa(G) of the reactor, the DCS sends a signal to open the second delivery valve 6. The second delivery valve 6 receives the signal. The active components are delivered to the reactor 7 under pressure and gravity. During the process, the pressure is continuously replenished to control the pressure of the isolation tank 4 to be higher than that of the reactor 7≮0.1MPa(G). The DCS sends a signal to close the second delivery valve 6 and the isolation tank pressure charging valve 11. The second delivery valve 6 is closed after receiving the signal, and the isolation tank pressure charging valve 11 is closed after receiving the signal. The DCS sends a signal to open the isolation tank pressure relief valve 12. The isolation tank pressure relief valve 12 is opened after receiving the signal. After the isolation tank is depressurized to ≯0.01MPa(G), the DCS sends a signal to close the isolation tank pressure relief valve 12. The isolation tank pressure relief valve 12 is closed, and the material discharge control logic of the silo 2 is re-executed.

[0027] A weighing sensor 5 is provided at the lower part of the isolation tank 4, and the measured metering data is transmitted to the display position in the DCS to realize the accumulation of the filling amount.

[0028] According to the activity of the ionic liquid, the weighing target value is generally set at 5 to 30 kg / time.

Claims

1. A closed automatic operation system for an ionic liquid alkylation active agent, comprising: A PLC or DCS control device and a weighing sensor (5), wherein the PLC or DCS control device controls the automatic feeding in sequence, and is characterized in that: it also includes a pressure feeding tank (1), a silo (2), a first delivery valve (3), an isolation tank (4), a second delivery valve (6) and a reaction kettle (7) which are connected in sequence, and a cyclone separator (8), a bag dust collector (9) and an alkali cleaning dust collector (10) are arranged at the upper outlet of the silo (2); the pressure feeding tank (1) is arranged on the ground; the weighing sensor (5) is arranged below the isolation tank (4); the pressure feeding tank (1) is provided with pressurized dry nitrogen for conveying the active agent, and the conveying pressure of the pressurized dry nitrogen is 0.2 to 10000 W. 0.5MPa(G), the active agent is delivered to the silo (2) by pressure delivery; the active agent flows from the silo (2) by gravity or is delivered by pressure to the isolation tank (4), and when the isolation tank (4) receives the material and weighs it to the target value, the first delivery valve (3) is closed; at this time, the charging solenoid valve (11) of the isolation tank (4) charges nitrogen into the isolation tank (4), and when the isolation tank (4) is pressurized to 0.1-0.5MPa(G), the second delivery valve (6) is opened, and the active agent is pressure-delivered to the reactor (7), and then the second delivery valve (6) and the isolation tank pressure-charging valve (11) are closed, and the isolation tank pressure relief valve (12) is opened to relieve the pressure of the isolation tank, and the above-mentioned feeding process is repeated to achieve continuous and stable operation.

2. The closed automatic operation system of an ionic liquid alkylation activator according to claim 1, characterized in that: The pressure tank (1) is a plurality of independent pressure tanks with cylindrical conical bottoms, each of which has a capacity of 2 to 3 m 3 , pressure resistance level 1.0MPa(G), nitrogen consumption per pressure tank (1) 200~300Nm 3 / h.

3. The closed automatic operation system of an ionic liquid alkylation activator according to claim 1, characterized in that: The active agent is solid particle powder with a particle size of 30 to 600 μm.

4. The closed automatic operation system of an ionic liquid alkylation activator according to claim 1, characterized in that: The dry nitrogen is used as the conveying gas, and the pressure of the dry nitrogen is ≥0.5MPa(G).

5. The closed automatic operation system of an ionic liquid alkylation activator according to claim 1, characterized in that: The active agent enters the silo (2) tangentially along the tank wall.

6. The closed automatic operation system of an ionic liquid alkylation activator according to claim 1, characterized in that: The isolation tank (4) has a volume of 0.1 to 0.2 m 3 , cylindrical cone bottom.

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