阅读说明：本技术 丙烯保护床系统以及丙烯输送方法 (Propylene guard bed system and propylene delivery method ) 是由 周强强 杜振国 史小锋 董晨 于 2020-05-21 设计创作，主要内容包括：本发明公开了一种丙烯保护床系统以及丙烯输送方法,丙烯保护床系统的保护床本体包括床体进口以及床体出口；丙烯进料线和床体进口流体连通并且丙烯进料线和床体进口之间设有用于控制流体通断的第一阀；丙烯出料线和床体出口流体连通并且丙烯出料线和床体出口之间设有用于控制流体通断的第三阀；第一冷却器的第一冷却进口与床体出口流体连通,第一冷却器的第一冷却出口与丙烯输送泵的泵进口流体连通,丙烯输送泵的泵出口与床体进口流体连通,第一冷却进口与床体出口之间设有用于控制流体通断的第五阀。本发明的丙烯保护床系统能够有效的降低液相丙烯进入时产生的吸附热,从而避免了因吸附热导致的超压风险。(The invention discloses a propylene protection bed system and a propylene conveying method, wherein a protection bed body of the propylene protection bed system comprises a bed body inlet and a bed body outlet; the propylene feeding line is communicated with the fluid of the bed body inlet, and a first valve for controlling the on-off of the fluid is arranged between the propylene feeding line and the bed body inlet; the propylene discharging line is communicated with the fluid of the bed outlet, and a third valve for controlling the on-off of the fluid is arranged between the propylene discharging line and the bed outlet; the first cooling inlet of the first cooler is in fluid communication with the bed body outlet, the first cooling outlet of the first cooler is in fluid communication with the pump inlet of the propylene delivery pump, the pump outlet of the propylene delivery pump is in fluid communication with the bed body inlet, and a fifth valve for controlling the on-off of fluid is arranged between the first cooling inlet and the bed body outlet. The propylene protection bed system can effectively reduce the adsorption heat generated when liquid-phase propylene enters, thereby avoiding the overpressure risk caused by the adsorption heat.)

1. A propylene guard bed system, characterized in that it comprises a guard bed body, a propylene feed line (101), a propylene discharge line (102), a regeneration gas inlet line (103), a regeneration gas outlet line (104), a first cooler (201), and a propylene transfer pump (105);

the protective bed body comprises a bed body inlet and a bed body outlet;

the propylene feeding line (101) is communicated with the bed inlet in a fluid mode, and a first valve (401) for controlling the on-off of the fluid is arranged between the propylene feeding line (101) and the bed inlet;

the regeneration gas outlet line (104) is in fluid communication with the bed inlet, and a second valve (402) for controlling the on-off of fluid is arranged between the regeneration gas outlet line (104) and the bed inlet;

the propylene discharging line (102) is communicated with the bed outlet in a fluid mode, and a third valve (403) for controlling the on-off of the fluid is arranged between the propylene discharging line (102) and the bed outlet;

the regeneration gas inlet line (103) is in fluid communication with the bed outlet, and a fourth valve (404) for controlling the on-off of fluid is arranged between the regeneration gas inlet line (103) and the bed outlet;

the first cooling inlet of the first cooler (201) is in fluid communication with the bed outlet, the first cooling outlet of the first cooler (201) is in fluid communication with the pump inlet of the propylene conveying pump (105), the pump outlet of the propylene conveying pump (105) is in fluid communication with the bed inlet, and a fifth valve (405) for controlling the on-off of fluid is arranged between the first cooling inlet and the bed outlet.

2. Propylene guard bed system according to claim 1, characterized in that the bed outlet is provided with a first temperature monitoring unit (301) for monitoring the temperature of the fluid flowing out of the bed outlet.

3. The propylene guard bed system according to claim 2, wherein the propylene guard bed system comprises a propylene collection tank (106), the first cooling outlet is in fluid communication with a tank inlet of the propylene collection tank (106), a tank outlet of the propylene collection tank (106) is in fluid communication with a pump inlet of the propylene transfer pump (105), and a sixth valve (406) for controlling the on-off of the fluid is arranged between the tank outlet of the propylene collection tank (106) and the pump inlet of the propylene transfer pump (105).

4. The propylene guard bed system according to claim 3, wherein the guard bed body comprises a first bed (501) and a second bed (502) independent from each other; the first bed (501) has a first inlet and a first outlet as the bed outlet, and the second bed (502) has a second outlet and a second inlet as the bed inlet;

the propylene guard bed system comprises a second cooler (202), the second outlet being in fluid communication with a second cooling inlet of the second cooler (202), a second cooling outlet of the second cooler (202) being in fluid communication with the first inlet.

5. A propylene guard bed system according to claim 4, characterized in that a seventh valve (407) for controlling the fluid on-off is arranged between the second outlet and the second cooling inlet and/or an eighth valve (408) for controlling the fluid on-off is arranged between the second cooling outlet and the first inlet.

6. The propylene guard bed system according to claim 4, wherein a branch line (107) is provided between the first inlet and the second outlet in parallel with the second cooler (202), the branch line (107) being provided with a ninth valve (409).

7. The propylene guard bed system according to claim 4, wherein the second cooling outlet is provided with a second temperature monitoring unit (302) for monitoring the temperature of the fluid flowing out of the second cooling outlet.

8. Propylene guard bed system according to claim 1, characterized in that between the pump outlet of the propylene transfer pump (105) and the bed inlet there is a regulating valve (410) for regulating the flow of fluid.

9. A propylene guard bed system as claimed in claim 1, wherein a third temperature monitoring unit (303) is provided at the bed inlet for monitoring the temperature of the fluid.

10. A method for propylene delivery, comprising the steps of:

s1, introducing propylene to the first bed (501) from the propylene feed line (101) through the second bed (502) and the second cooler (202) in sequence;

s2, introducing propylene from the first bed (501) to a propylene collecting tank (106) through a first cooler (201);

s3, when the propylene in the propylene collecting tank (106) reaches a preset amount, closing the propylene feeding line (101) and starting a propylene conveying pump (105) at the same time, so that the propylene is circulated among the second bed (502), the second cooler (202), the first bed (501), the first cooler (201), the propylene collecting tank (106) and the propylene conveying pump (105);

s4, when the temperature of propylene at the first outlet of the first bed (501) reaches a preset temperature, closing the propylene conveying pump (105), and simultaneously closing a pipeline between the first bed (501) and the first cooler (201) and a pipeline between the second bed (502) and the second cooler (202);

s5, opening a branch line (107) between the first bed (501) and the second bed (502) and connected with the second cooler (202) in parallel;

s6, opening the propylene feeding line (101) and making the propylene flow out of the propylene discharging line (102) after passing through the second bed layer (502) and the first bed layer (501) in sequence.

Technical Field

The invention relates to the field of petrochemical industry, in particular to a propylene guard bed system and a propylene conveying method.

Background

The propylene protection bed system is used for removing oxides such as methanol, dimethyl ether and the like in propylene products, and an inlet and an outlet of the propylene protection bed system are respectively provided with an online analyzer for analyzing substances such as methanol, ethylene, ethane, propane, dimethyl ether and the like at the inlet and the outlet. The propylene guard bed system comprises two guard beds, wherein one guard bed is in normal operation, the other guard bed is in standby or regeneration, and the regeneration period is 48 hours. The guard bed outlet was immediately cut into the new/regenerated guard bed as soon as oxide was found to be present. When the guard bed has been regenerated and put into service again, it must be cooled as close as possible to the normal operating temperature. The guard bed is slowly cooled with cold regeneration gas until the bed temperature reaches about 40 ℃. And then filling and decompressing the top gas of the propylene rectifying tower for 3 times, replacing the nitrogen in the protective bed, slowly filling and compressing to 1.8MPa (G), sending the propylene stored in the buffer tank of the protective bed into the regenerated protective bed, filling the regenerated protective bed with the liquid-phase propylene for backup, putting the backup protective bed into use in time once the oxide exists at the outlet of the propylene protective bed system, and cutting the original online protective bed out for regeneration.

However, the above-mentioned liquid-filled standby process has the following problems: when the regenerated propylene protection bed system is filled with liquid for the first time, adsorption heat is generated after liquid-phase propylene enters the protection bed, the temperature of the whole protection bed begins to rise, the liquid-phase propylene is partially gasified, an operator needs to open the pressure release valve in time to release the pressure, if the pressure is not released, the temperature of the protection bed rises quickly, the pressure rises quickly, and the risk of overpressure exists. In addition, in the pressure relief process, if the pressure is relieved to a torch system, a large amount of propylene is wasted, and if the pressure is relieved to a front system, when the front system runs at full load, the relief amount is limited, so that the overpressure of a propylene protection bed system is easily caused.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provides a propylene protection bed system and a propylene conveying method.

In order to achieve the above object, the present invention provides a propylene guard bed system comprising a guard bed body, a propylene feeding line, a propylene discharging line, a regeneration gas inlet line, a regeneration gas outlet line, a first cooler, and a propylene transfer pump; the protective bed body comprises a bed body inlet and a bed body outlet; the propylene feeding line is communicated with the bed inlet in a fluid mode, and a first valve used for controlling the on-off of the fluid is arranged between the propylene feeding line and the bed inlet; the regeneration gas outlet line is in fluid communication with the bed body inlet, and a second valve for controlling the on-off of fluid is arranged between the regeneration gas outlet line and the bed body inlet; the propylene discharging line is communicated with the bed outlet in a fluid mode, and a third valve used for controlling the on-off of the fluid is arranged between the propylene discharging line and the bed outlet; the regeneration gas inlet line is communicated with the bed outlet in a fluid mode, and a fourth valve used for controlling the on-off of the fluid is arranged between the regeneration gas inlet line and the bed outlet; the first cooling inlet of the first cooler is in fluid communication with the bed outlet, the first cooling outlet of the first cooler is in fluid communication with the pump inlet of the propylene delivery pump, the pump outlet of the propylene delivery pump is in fluid communication with the bed inlet, and a fifth valve for controlling the on-off of fluid is arranged between the first cooling inlet and the bed outlet.

Optionally, a first temperature monitoring unit for monitoring the temperature of the fluid flowing out of the bed outlet is arranged at the bed outlet.

Optionally, the propylene protection bed system includes a propylene collection tank, the first cooling outlet is in fluid communication with a tank inlet of the propylene collection tank, a tank outlet of the propylene collection tank is in fluid communication with a pump inlet of the propylene delivery pump, and a sixth valve for controlling the on-off of fluid is arranged between the tank outlet of the propylene collection tank and the pump inlet of the propylene delivery pump.

Optionally, the guard bed body comprises a first bed layer and a second bed layer which are independent of each other; the first bed layer is provided with a first inlet and a first outlet which is used as the bed outlet, and the second bed layer is provided with a second outlet and a second inlet which is used as the bed inlet; the propylene guard bed system comprises a second cooler, the second outlet in fluid communication with a second cooling inlet of the second cooler, the second cooling outlet of the second cooler in fluid communication with the first inlet.

Optionally, a seventh valve for controlling the on-off of the fluid is arranged between the second outlet and the second cooling inlet, and/or an eighth valve for controlling the on-off of the fluid is arranged between the second cooling outlet and the first inlet.

Optionally, a branch pipeline connected in parallel with the second cooler is arranged between the second outlet and the first inlet, and a ninth valve is arranged on the branch pipeline.

Optionally, a second temperature monitoring unit for monitoring the temperature of the fluid flowing out of the second cooling outlet is arranged at the second cooling outlet.

Optionally, a regulating valve for regulating the flow of the fluid is arranged between the pump outlet of the propylene delivery pump and the bed body inlet.

Optionally, a third temperature monitoring unit for monitoring the temperature of the fluid is arranged at the bed inlet.

The invention also provides a propylene conveying method, which comprises the following steps: s1, introducing propylene to the first bed layer from a propylene feed line through the second bed layer and the second cooler in sequence; s2, introducing propylene from the first bed layer to a propylene collecting tank through a first cooler; s3, when the propylene in the propylene collecting tank reaches a preset amount, closing the propylene feeding line and starting a propylene conveying pump at the same time, so that the propylene is circulated among the second bed layer, the second cooler, the first bed layer, the first cooler, the propylene collecting tank and the propylene conveying pump; s4, when the temperature of propylene at the first outlet of the first bed layer reaches a preset temperature, closing the propylene delivery pump, and simultaneously closing a pipeline between the first bed layer and the first cooler and a pipeline between the second bed layer and the second cooler; s5, opening a branch line which is connected with the second cooler in parallel between the first bed and the second bed; s6, opening the propylene feeding line, and enabling propylene to flow out of the propylene discharging line after sequentially passing through the second bed layer and the first bed layer.

According to the technical scheme, when propylene starts to be conveyed, the first valve and the fifth valve are opened, so that propylene flows from the propylene feed line to the bed inlet, the propylene flows out from the bed outlet after oxides such as methanol, dimethyl ether and the like are removed from a protective bed body, and flows back to the bed inlet through the second cooler, the first cooler and the propylene conveying pump in sequence under the pumping action of the propylene conveying pump, circulation is realized, the circulated propylene is cooled to a desired temperature, such as 40 ℃, under the cooling action of the second cooler and the first cooler, the fifth valve and the propylene conveying pump are closed, the third valve is opened, the propylene entering from the propylene feed line can flow out from the propylene discharge line with the cooled propylene, and the conveying work of the propylene is completed. And then, the adsorption heat generated when the propylene enters the protective bed body can be effectively reduced by repeating the steps, so that the overpressure risk caused by the adsorption heat is avoided.

When the protective bed body needs to be regenerated, for example, when oxides exist in propylene at the outlet of the bed body, the first valve, the third valve, the fifth valve and the propylene delivery pump are closed, the second valve and the fourth valve are opened, and then the regeneration gas can flow into the protective bed body from the regeneration gas inlet line and flow out from the regeneration gas outlet line, so that the regeneration of the protective bed body is realized.

Drawings

FIG. 1 is a schematic diagram of one embodiment of the propylene guard bed system of the present invention.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

As shown in fig. 1, the propylene guard bed system of the present invention comprises a guard bed body, a propylene feed line 101, a propylene effluent line 102, a regeneration gas inlet line 103, a regeneration gas outlet line 104, a first cooler 201, and a propylene transfer pump 105; the protective bed body comprises a bed body inlet and a bed body outlet; the propylene feeding line 101 is communicated with the fluid of the bed inlet, and a first valve 401 for controlling the on-off of the fluid is arranged between the propylene feeding line 101 and the bed inlet; the regeneration gas outlet line 104 is in fluid communication with the bed inlet, and a second valve 402 for controlling the on-off of the fluid is arranged between the regeneration gas outlet line 104 and the bed inlet; the propylene outlet line 102 is in fluid communication with the bed outlet and a third valve 403 for controlling the fluid connection is arranged between the propylene outlet line 102 and the bed outlet; the regeneration gas inlet line 103 is in fluid communication with the bed outlet and a fourth valve 404 for controlling the on-off of the fluid is arranged between the regeneration gas inlet line 103 and the bed outlet; the first cooling inlet of the first cooler 201 is in fluid communication with the bed outlet, the first cooling outlet of the first cooler 201 is in fluid communication with the pump inlet of the propylene pump 105, the pump outlet of the propylene pump 105 is in fluid communication with the bed inlet, and a fifth valve 405 for controlling the on-off of fluid is arranged between the first cooling inlet and the bed outlet.

In the present invention, when the propylene starts to be transported, the first valve 401 and the fifth valve 405 are opened to allow the propylene to flow from the propylene feed line 101 to the bed inlet, the propylene flows out from the bed outlet after removing the oxides such as methanol, dimethyl ether, etc. in the protective bed body, and flows back to the bed inlet through the second cooler 202, the first cooler 201 and the propylene transport pump 105 in sequence under the pumping action of the propylene transport pump 105, so as to realize circulation, the propylene after circulation is cooled by the second cooler 202 and the first cooler 201 to a desired temperature, for example, 40 ℃, at this time, the fifth valve 405 and the propylene transport pump 105 are closed again, the third valve 403 is opened, and the propylene coming from the propylene feed line 101 flows out from the propylene discharge line 102 with the cooled propylene, and the propylene transport work is completed. And then, the adsorption heat generated when the propylene enters the protective bed body can be effectively reduced by repeating the steps, so that the overpressure risk caused by the adsorption heat is avoided.

When the guard bed body needs to be regenerated, for example, when oxides exist in propylene at the bed body outlet, the first valve 401, the third valve 403, the fifth valve 405 and the propylene delivery pump 105 are closed, the second valve 402 and the fourth valve 404 are opened, and the regeneration gas can flow into the guard bed body from the regeneration gas inlet line 103 and flow out from the regeneration gas outlet line 104, so that the regeneration of the guard bed body is realized.

In order to monitor whether the temperature of the propylene in the above circulation process is reduced to a desired temperature, in an embodiment of the present invention, a first temperature monitoring unit 301 for monitoring the temperature of the fluid flowing out of the bed outlet is arranged at the bed outlet, and when the first temperature monitoring unit 301 monitors that the temperature of the propylene flowing out of the bed outlet is reduced to a desired temperature, for example, 40 ℃, the first temperature monitoring unit 301 can send a signal to an external control mechanism.

In order to solve the problem that the amount of propylene cooled by the circulating cooling is limited in the above embodiment, so that a certain amount of propylene can be delivered by the circulating cooling for many times, in an embodiment of the present invention, the propylene guard bed system includes a propylene collecting tank 106, a first cooling outlet is in fluid communication with a tank inlet of the propylene collecting tank 106, a tank outlet of the propylene collecting tank 106 is in fluid communication with a pump inlet of the propylene conveying pump 105, and a sixth valve 406 for controlling the on-off of the fluid is arranged between the tank outlet of the propylene collecting tank 106 and the pump inlet of the propylene conveying pump 105. When propylene is conveyed, the first valve 401, the fifth valve 405 and the sixth valve 406 are opened, so that propylene flows from the propylene feeding line 101 to the bed inlet, the propylene flows out from the bed outlet after oxides such as methanol, dimethyl ether and the like are removed from the protective bed body, and after a certain amount of propylene is collected in the propylene collecting tank 106, the propylene returns to the bed inlet through the propylene conveying pump 105 to realize circulation, so that the flow of the propylene in the circulation process can be increased, the circulation cooling frequency is reduced, and the conveying efficiency of the propylene is greatly improved.

In order to further reduce the heat of adsorption generated when propylene enters the guard bed body and avoid the risk of overpressure caused by the heat of adsorption, in one embodiment of the invention, the guard bed body comprises a first bed 501 and a second bed 502 which are independent from each other; the first bed 501 has a first inlet and a first outlet as a bed outlet, and the second bed 502 has a second outlet and a second inlet as a bed inlet; the propylene guard bed system comprises a second cooler 202, a second outlet in fluid communication with a second cooling inlet of the second cooler 202, and a second cooling outlet of the second cooler 202 in fluid communication with the first inlet. Therefore, when propylene enters from the propylene feeding line 101, the propylene firstly enters the second bed 502, after partial removal of oxides in the second bed 502, the propylene directly enters the second cooler 202 for temperature reduction treatment, which can effectively reduce a part of adsorption heat, then the propylene enters the first bed 501 again for oxide removal, and enters the first cooler 201 for second cooling after exiting from the first bed 501, that is, during one cycle cooling, the propylene will pass through the second cooler 202 and the first cooler 201 in sequence for twice cooling, and the first cooling performed by the second cooler 202 can be regarded as that the propylene is completed in the protection bed body, so that the adsorption heat generated by the propylene is greatly reduced, and the risk of overpressure caused by the adsorption heat is effectively avoided.

In order to effectively control the on-off of the first bed 501, the second bed 502 and the second cooler 202, specifically, a seventh valve 407 for controlling the on-off of the fluid is arranged between the second outlet and the second cooling inlet, and an eighth valve 408 for controlling the on-off of the fluid is arranged between the second cooling outlet and the first inlet.

When the temperature of the propylene is reduced to the desired temperature, the propylene is not desired to pass through the second cooler 202, therefore, a branch pipeline 107 connected with the second cooler 202 in parallel is arranged between the second outlet and the first inlet, a ninth valve 409 is arranged on the branch pipeline 107, therefore, the branch pipeline 107 can be disconnected by closing the ninth valve 409 so as to circularly cool the propylene, when the temperature of the propylene is reduced to the desired temperature, the seventh valve 407 and the eighth valve 408 are closed, and the ninth valve 409 is opened at the same time, so that the cooled propylene cannot pass through the second cooler 202.

In order to more reliably monitor whether the temperature of the propylene is reduced to a desired temperature, optionally, the second cooling outlet is provided with a second temperature monitoring unit 302 for monitoring the temperature of the fluid flowing out from the second cooling outlet.

Meanwhile, a third temperature monitoring unit 303 for monitoring the temperature of the fluid can be arranged at the inlet of the bed body so as to further improve the monitoring range of the temperature of the propylene.

In the above embodiment, specifically, a regulating valve 410 for regulating the flow rate of the fluid is provided between the pump outlet of the propylene pump 105 and the bed inlet. Therefore, the flow rate and the flow rate of propylene during the cooling cycle can be effectively controlled by adjusting the valve 410, thereby achieving more effective cooling.

The invention also provides a propylene conveying method which can be used as an operation method of the propylene guard bed system and comprises the following specific steps:

s1, introducing propylene to the first bed 501 from the propylene feed line 101 through the second bed 502 and the second cooler 202 in sequence;

s2, introducing propylene from the first bed 501 to the propylene collecting tank 106 through the first cooler 201;

s3, when the propylene in the propylene collecting tank 106 reaches a preset amount, closing the propylene feeding line 101 and starting the propylene conveying pump 105 at the same time, so that the propylene is circulated among the second bed layer 502, the second cooler 202, the first bed layer 501, the first cooler 201, the propylene collecting tank 106 and the propylene conveying pump 105;

s4, when the temperature of propylene at the first outlet of the first bed layer 501 reaches a preset temperature, closing the propylene conveying pump 105, closing a pipeline between the first bed layer 501 and the first cooler 201, and closing a pipeline between the second bed layer 502 and the second cooler 202;

s5, opening a branch line 107 connected with the second cooler 202 in parallel between the first bed 501 and the second bed 502;

s6, opening the propylene feeding line 101, and making the propylene flow out of the propylene discharging line 102 after passing through the second bed layer 502 and the first bed layer 501 in sequence.

The propylene transport method of the present invention has the same advantages as the propylene guard bed system described above over the prior art, and will not be described herein again.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications may be made to the technical solution of the invention, and in order to avoid unnecessary repetition, various possible combinations of the invention will not be described further. Such simple modifications and combinations should be considered within the scope of the present disclosure as well.