System for on-line experiment of performance of maleic anhydride catalyst prepared by oxidation of n-butane

Abstract

The utility model relates to a method and a structure for testing the performance of a catalyst in a maleic anhydride preparation device, in particular to a system for testing the performance of a maleic anhydride catalyst prepared by n-butane oxidation on line, which comprises a main oxidation reactor, the main oxidation reactor is provided with a fused salt circulating system through a pipeline, and the fused salt circulating system is connected with a newly added side line flow path; a side line inlet and outlet analysis system is arranged in the newly added side line process; a side line reactor is led out from a main oxidation reactor of a maleic anhydride device and is connected with a molten salt circulating system; catalyst performance can be experimented on line, and experimental data is high in accuracy; the catalyst is used for experiments to compare the performance of the catalyst in the market, and has high activity and good selectivity. Meanwhile, the performance of various catalysts can be tested and compared at the same time, the catalysts are online at the same time, and experimental data accuracy is high; the fused salt after heat transfer is fed into an original device salt cooler through a small fused salt pump, and high-pressure steam can be produced as a byproduct to create additional value; yield increase and enterprise economic benefits are improved for preparation of maleic anhydride products.

Description

Technical Field

[0001] The utility model relates to a test method and structure for catalyst performance in a maleic anhydride preparation device, in particular to a system for online testing of catalyst performance for preparing maleic anhydride by oxidation of n-butane, which is used in a process system for preparing maleic anhydride by n-butane oxidation, and belongs to the technical field of chemical industry. Background Art

[0002] The production capacity of a single unit of the n-butane oxidation process for producing maleic anhydride is 210,000 tons of maleic anhydride per year. The amount of catalyst replaced at one time is 200 tons. There is a risk that the catalyst activity and selectivity will not meet expectations after one loading. The catalyst is costly and has a long life. Poor catalyst selection will affect the unit's output and product quality for 5-8 years. Utility Model Content

[0003] In view of the above-mentioned technical problems in the preparation of maleic anhydride, the purpose of the utility model is to provide a system for online testing of the performance of catalysts for preparing maleic anhydride by oxidation of n-butane, by leading out a side line reactor from the main oxidation reactor of the maleic anhydride device and connecting it to a molten salt circulation system; the catalyst performance can be tested online with high accuracy of experimental data; it is used to experimentally compare the performance of catalysts on the market and select catalysts with high activity and good selectivity; the experimental reliability is high.

[0004] In order to achieve the above-mentioned purpose, the technical scheme adopted by the utility model is: a system for online experiment of catalyst performance of n-butane oxidation to maleic anhydride, comprising: a main oxidation reactor, the main oxidation reactor is provided with a molten salt circulation system through a pipeline, the molten salt circulation system is connected with a newly added side line process; a side line inlet and outlet analysis system is provided in the newly added side line process;

[0005] The catalyst performance can be experimentally obtained by adding a side line reactor process to the main oxidation reactor, and then analyzing the inlet and outlet components of the side line reactor, and alternately sampling and analyzing the main oxidation reactor and the side line reactor;

[0006] In the system of this scheme, a raw material feeding process is set on one side of the main oxidation reactor, and the raw material feeding process includes an n-butane raw material line, from which gaseous n-butane is introduced; and also includes an air raw material pipeline above the n-butane raw material line, the top of the n-butane raw material line is mixed with the air raw material pipeline, and is connected to the top of the main oxidation reactor through a raw material mixer;

[0007] Furthermore, the molten salt circulation system includes: a large molten salt pump, a small molten salt pump and a salt cooler; the large molten salt pump is arranged on one side of the main oxidation reactor, and the side wall of the main oxidation reactor is connected to the upper side wall of the large molten salt pump through a pipeline, which is the inlet position of the large molten salt pump; the side wall of the main oxidation reactor is connected to the lower side wall of the large molten salt pump through a pipeline, which is the outlet position of the large molten salt pump; a salt injection pipeline is arranged at the bottom of the large molten salt pump;

[0008] A circulation pipeline is arranged on the side wall of the large molten salt pump on the opposite side of the inlet and outlet of the large molten salt pump, and the circulation pipeline includes a feed line and a return line. The feed line is led out from the side wall of the large molten salt pump and connected to the inlet of the small molten salt pump, and is led out from the outlet of the small molten salt pump and connected to the salt cooler; the return line is led out from the outlet of the salt cooler and connected back to the large molten salt pump, thereby forming a circulation pipeline process;

[0009] The above-mentioned feed line and return line refer to the feed and discharge of molten salt;

[0010] The function of the salt cooler is to generate high-pressure steam by heat exchange between molten salt and boiler water;

[0011] Furthermore, the newly added side line process connection relies on the molten salt circulation system, and the newly added side line process includes: a side line reactor, a side line reactor feed line, and a side line reactor discharge line; the side line reactor feed line and the side line reactor discharge line are located at the same end of the side line reactor; the side line reactor feed line is led out from the outlet of the large molten salt pump of the molten salt circulation system and connected to the side line reactor, and the side line reactor discharge line is led out from the side line reactor and returned to the inlet position of the large molten salt pump and mixed with the molten salt at the inlet of the large molten salt pump;

[0012] Similarly, the side line reactor feed line and the side line reactor discharge line refer to the feed and discharge of molten salt;

[0013] The side wall of the side line reactor at the opposite end to the side line reactor feed line and the side line reactor discharge line is also connected to the small molten salt tank and the large molten salt tank through pipelines respectively;

[0014] Among them, the setting of small molten salt tank is used to store molten salt containers. During the use of molten salt, overflow and liquid level gap occur due to temperature changes, and salt replenishment and overflow storage are required; the setting of large molten salt tank, the system has more molten salt, which is used for maintenance molten salt return and initial start-up configuration of molten salt;

[0015] Furthermore, the side line inlet and outlet analysis systems provided in the newly added side line process are respectively an inlet online analyzer and an outlet online analyzer of the side line reactor; the inlet online analyzer is provided on the feed pipeline at the top of the main oxidation reactor, and the outlet online analyzer is connected to the bottom of the side reactor through a pipeline;

[0016] The online analysis of the side line reactor inlet and outlet relies on the online analysis of the main oxidation reactor. The raw materials imported by the side line reactor are consistent with those of the main oxidation reactor, and the online analysis data of the main oxidation reactor inlet is adopted. The gas at the side line reactor outlet is introduced into the online analyzer at the main oxidation reactor outlet, and the main oxidation reactor and the side line reactor are sampled and analyzed alternately, and the test is carried out approximately every 15 minutes. The reliability has been verified in the main device, and no additional online analysis facilities are added.

[0017] This scheme can experimentally obtain the catalyst performance through the analysis of the inlet and outlet components of the side line reactor. The performance parameters are calculated as follows:

[0018] a) Selectivity = 1-(CO (export)-CO (import)+CO2 (export)-CO2 (import)) / (butane (import)-butane (export))

[0019] b) Conversion rate = (butane (import) - butane (export)) / butane (import).

[0020] Furthermore, in the system of the present solution, a molten salt electric heater is also provided for heating the reactor before it is put into use to avoid solidification of the molten salt and to meet the feed temperature.

[0021] Beneficial effects of the system for online testing the performance of the catalyst for producing maleic anhydride by oxidation of n-butane using the utility model:

[0022] By leading out a side line reactor from the main oxidation reactor of the maleic anhydride unit and connecting it to the molten salt circulation system, the catalyst performance can be tested online with high accuracy of experimental data; it can be used to experimentally compare the performance of catalysts on the market and select catalysts with high activity and good selectivity;

[0023] At the same time, the performance of multiple catalysts can be experimentally compared at the same time. The catalysts are online at the same time, and the experimental data is highly accurate. The molten salt after heat transfer is pumped into the salt cooler of the original device through a small molten salt pump, which can produce high-pressure steam as a by-product to create additional value. This can increase production and improve the economic benefits of the enterprise for the preparation of maleic anhydride products. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural diagram of the utility model system.

[0025] Figure 2 for Figure 1 A partial enlarged view of .

[0026] In the figure, 1, main oxidation reactor, 2, n-butane raw material line, 3, air raw material pipeline, 4, raw material mixer, 5, large molten salt pump, 6, small molten salt pump, 7, salt cooler, 8, salt injection pipeline, 9, feed line, 10, return line, 11, side line reactor, 12, side line reactor feed line, 13, side line reactor discharge line, 14, small molten salt tank, 15, large molten salt tank, 16, import online analyzer, 17, export online analyzer, 18, molten salt electric heater. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below. Example

[0028] like Figure 1 , 2 The system for online experiment of catalyst performance of n-butane oxidation to maleic anhydride shown in the figure comprises: a main oxidation reactor 1, wherein the main oxidation reactor 1 is provided with a molten salt circulation system through a pipeline, wherein the molten salt circulation system is connected to a newly added side line process; and a side line inlet and outlet analysis system is provided in the newly added side line process;

[0029] A raw material feeding process is arranged on one side of the main oxidation reactor 1, and the raw material feeding process includes an n-butane raw material line 2, from which gaseous n-butane is introduced; and also includes an air raw material pipeline 3 above the n-butane raw material line 2, and the top of the n-butane raw material line 2 is mixed with the air raw material pipeline 3 and connected to the top of the main oxidation reactor 1 through a raw material mixer 4;

[0030] Furthermore, the molten salt circulation system includes: a large molten salt pump 5, a small molten salt pump 6 and a salt cooler 7; the large molten salt pump 5 is arranged on one side of the main oxidation reactor 1, and the side wall of the main oxidation reactor 1 is connected to the upper side wall of the large molten salt pump 5 through a pipeline, which is the inlet position of the large molten salt pump 5; the side wall of the main oxidation reactor 1 is connected to the lower side wall of the large molten salt pump 5 through a pipeline, which is the outlet position of the large molten salt pump 5; the bottom end of the large molten salt pump 5 is provided with a salt injection pipeline 8;

[0031] A circulation pipeline is arranged on the side wall of the large molten salt pump 5 on the opposite side to the inlet and outlet of the large molten salt pump 5, and the circulation pipeline includes a feed line 9 and a return line 10. The feed line 9 is led out from the side wall of the large molten salt pump 5 and connected to the inlet of the small molten salt pump 6, and is led out from the outlet of the small molten salt pump 6 and connected to the salt cooler 7; the return line 10 is led out from the outlet of the salt cooler 7 and connected back to the large molten salt pump 5, thereby forming a circulation pipeline process;

[0032] The newly added side line process connection relies on the molten salt circulation system, and the newly added side line process includes: a side line reactor 11, a side line reactor feed line 12, and a side line reactor discharge line 13; the side line reactor feed line 12 and the side line reactor discharge line 13 are located at the same end of the side line reactor 11; the side line reactor feed line 12 is drawn out from the outlet of the large molten salt pump 5 of the molten salt circulation system and connected to the side line reactor 11, and the side line reactor discharge line 13 is drawn out from the side line reactor 11 and returned to the inlet position of the large molten salt pump 5 and mixed with the molten salt at the inlet of the large molten salt pump 5;

[0033] The side wall of the side line reactor 11 at the opposite end to the side line reactor feed line 12 and the side line reactor discharge line 13 is also connected to a small molten salt tank 14 and a large molten salt tank 15 through pipelines respectively;

[0034] The side line inlet and outlet analysis systems provided in the newly added side line process are respectively the inlet online analyzer 16 and the outlet online analyzer 17 of the side line reactor 11; the inlet online analyzer 16 is provided on the feed pipeline at the top of the main oxidation reactor 1, and the outlet online analyzer 17 is connected to the bottom of the side line reactor 11 through a pipeline;

[0035] The online analysis of the inlet and outlet of the side line reactor 11 relies on the online analysis of the main oxidation reactor 1. The inlet raw materials of the side line reactor 11 are consistent with those of the main oxidation reactor 1, and the inlet online analysis data of the main oxidation reactor 1 is used; the outlet gas of the side line reactor 11 is introduced into the online analyzer 17 at the outlet of the main oxidation reactor, and the main oxidation reactor 1 and the side line reactor 11 are sampled and analyzed alternately, and the detection is performed once every 15 minutes. A molten salt electric heater 18 is also provided in the system, which is used to heat and raise the temperature before the reactor is put into use to avoid solidification of the molten salt and meet the feed temperature.

[0036] The embodiment of this scheme takes a molten salt circulation system of the maleic anhydride main oxidation reactor 1 as an example, and serves as another embodiment of the above scheme.

[0037] Example 2

[0038] As a further optimization of the effect of the above technical solution, the utility model can use a maleic anhydride main oxidation reactor 1 to prepare three molten salt circulation systems, and the three molten salt circulation systems are evenly distributed around the main oxidation reactor 1, and each molten salt circulation system corresponds to a side line reactor 11, and the performance of three catalysts can be experimentally compared at the same time. The catalysts are online at the same time, and the experimental data is highly accurate;

[0039] In this embodiment, one main oxidation reactor 1 is evenly distributed with 3 sets of molten salt circulation systems. The molten salt is pressurized by a large molten salt pump 5 and enters the main oxidation reactor 1 from bottom to top to transfer the heat released by the oxidation reaction. Most of the molten salt out of the reactor 1 enters the large molten salt pump 5 for recycling, and a small part is pressurized by a small molten salt pump 6 and sent to the salt cooler 7 for indirect heat exchange with boiler water to generate high-pressure steam for external transmission. The molten salt after heat exchange is returned to the inlet of the large molten salt pump 5, mixed with high-temperature molten salt, and pressurized by the large molten salt pump 5 to enter the main oxidation reactor 1;

[0040] In this embodiment, three side line reactors 11 are evenly distributed around the main oxidation reactor 1, and each side line reactor 11 is connected to a molten salt circulation system. A small amount of molten salt is drawn from the outlet of the large molten salt pump 5 to the side line reactor 11, and the heat of the catalyst in the side line reactor 11 is taken out and returned to the inlet of the large molten salt pump 5 to mix with the molten salt at the inlet of the large molten salt pump 5. Since the side line reactor 11 uses a small amount of molten salt, the temperature rise of the overall molten salt system is not obvious. Except for the side line reactor 11, no other equipment investment is increased.

[0041] By analyzing the inlet and outlet components of the side line reactor 11, the performance of three catalysts can be experimentally compared at the same time, and the performance parameters are calculated as follows:

[0042] a) Selectivity = 1-(CO (export)-CO (import)+CO2 (export)-CO2 (import)) / (butane (import)-butane (export))

[0043] b) Conversion rate = (butane (import) - butane (export)) / butane (import).

[0044] With the original equipment and pipeline layout unchanged, a side line reactor 11 is added to a main oxidation reactor 1 to experimentally compare the performance of catalysts on the market and select catalysts with high activity and good selectivity. For every 1% increase in catalyst selectivity, the 210,000 tons / year maleic anhydride unit can increase the output of maleic anhydride products by 2,100 tons per year based on an annual operating time of 8,000 hours, thereby increasing the company's economic benefits by RMB 14.7 million.

[0045] Annual increase in maleic anhydride production = 26.25*0.01*8000=2100t

[0046] Annual economic benefit = 2100×7000=14.7 million yuan.

[0047] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0048] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0049] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0051] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

Claims

1. A system for online testing of catalyst performance for n-butane oxidation to maleic anhydride, characterized in that: include: A main oxidation reactor, wherein the main oxidation reactor is provided with a molten salt circulation system through pipelines, and the molten salt circulation system is connected to the newly added side line process; A side line inlet and outlet analysis system is provided in the newly added side line process.

2. The system for online testing the performance of a catalyst for producing maleic anhydride by oxidation of n-butane according to claim 1, characterized in that: A raw material feeding process is arranged on one side of the main oxidation reactor, and the raw material feeding process includes a n-butane raw material line, through which gaseous n-butane is introduced; and also includes an air raw material pipeline above the n-butane raw material line, the top of the n-butane raw material line is mixed with the air raw material pipeline, and is connected to the top of the main oxidation reactor through a raw material mixer.

3. The system for online testing the performance of a catalyst for producing maleic anhydride by oxidation of n-butane according to claim 1, characterized in that: The molten salt circulation system includes: a large molten salt pump, a small molten salt pump and a salt cooler; the large molten salt pump is arranged on one side of the main oxidation reactor, and the side wall of the main oxidation reactor is connected with the upper side wall of the large molten salt pump through a pipeline, which is the inlet position of the large molten salt pump; the side wall of the main oxidation reactor is connected with the lower side wall of the large molten salt pump through a pipeline, which is the outlet position of the large molten salt pump; a salt injection pipeline is provided at the bottom of the large molten salt pump.

4. The system for online testing the performance of a catalyst for producing maleic anhydride by oxidation of n-butane according to claim 3, characterized in that: A circulation pipeline is arranged on the side wall of the large molten salt pump on the opposite side of the inlet and outlet of the large molten salt pump, and the circulation pipeline includes a feed line and a return line. The feed line is led out from the side wall of the large molten salt pump and connected to the inlet of the small molten salt pump, and is led out from the outlet of the small molten salt pump and connected to the salt cooler; the return line is led out from the outlet of the salt cooler and connected back to the large molten salt pump, thereby forming a circulation pipeline flow.

5. The system for online testing the performance of a catalyst for producing maleic anhydride by oxidation of n-butane according to claim 3, characterized in that: The newly added side line process connection relies on the molten salt circulation system, and the newly added side line process includes: a side line reactor, a side line reactor feed line, and a side line reactor discharge line; the side line reactor feed line and the side line reactor discharge line are located at the same end of the side line reactor; the side line reactor feed line is led out from the outlet of the large molten salt pump of the molten salt circulation system and connected to the side line reactor, and the side line reactor discharge line is led out from the side line reactor and returned to the inlet position of the large molten salt pump and mixed with the molten salt at the inlet of the large molten salt pump.

6. The system for online testing the performance of a catalyst for producing maleic anhydride by oxidation of n-butane according to claim 5, characterized in that: The side wall of the side line reactor at the opposite end to the side line reactor feed line and the side line reactor discharge line is also connected to the small molten salt tank and the large molten salt tank through pipelines respectively.

7. The system for online testing the performance of a catalyst for producing maleic anhydride by oxidation of n-butane according to claim 1, characterized in that: The side line inlet and outlet analysis systems provided in the newly added side line process are respectively the inlet online analyzer and outlet online analyzer of the side line reactor; the inlet online analyzer is provided on the feed pipeline at the top of the main oxidation reactor, and the outlet online analyzer is connected to the bottom of the side reactor through a pipeline.

8. The system for online testing the performance of a catalyst for producing maleic anhydride by oxidation of n-butane according to claim 1, characterized in that: A molten salt electric heater is also provided.

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