A method for simultaneously loading new and old catalysts in an adiabatic conversion furnace

Abstract

The present invention discloses a method for simultaneously loading old and new catalysts in an adiabatic conversion furnace, which includes, when replacing the catalyst in the adiabatic conversion furnace, using a mixture of old and new catalysts instead of simply using new catalysts, so that the catalytic activity can be kept constant while slightly increasing the loading amount and the high temperature condition when replacing the catalyst can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of adiabatic conversion, and in particular relates to a method for simultaneously loading new and old catalysts into an adiabatic conversion furnace. Background Art

[0002] In conventional adiabatic conversion process devices, when the main reactor adiabatic conversion furnace is loaded with new catalyst, the new catalyst is filled in bulk. In the early stage of the use of the conversion catalyst, this filling method causes the catalyst bed of the adiabatic conversion furnace to frequently overheat due to the good low-temperature activity of the catalyst, low activation energy, high carbon monoxide conversion efficiency, and large heat release. The high temperature operation causes the carbon monoxide conversion reaction to be out of control, and the ratio of carbon monoxide and hydrogen at the outlet of the device is unbalanced, resulting in excessive venting and increased production costs. If the water-gas ratio in the raw coal gas at the inlet of the adiabatic conversion furnace is reduced, the inlet temperature is increased, the conversion rate is controlled, and the effective gas venting is reduced, the loss of low-temperature activity of the new catalyst is accelerated, and the service life of the catalyst is indirectly shortened. At the same time, when the adiabatic conversion device is started and the gas is guided, due to the high conversion rate and low air velocity, a large amount of reaction heat is retained in the catalyst bed, and the carbon monoxide methanation increases, causing the adiabatic conversion furnace to overheat, posing a major safety hazard. Summary of the invention

[0003] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0004] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0005] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for simultaneously loading new and old catalysts into an adiabatic conversion furnace.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for simultaneously loading new and old catalysts in an adiabatic conversion furnace, comprising: the adiabatic conversion furnace is divided into an upper half and a lower half, the bottom of the lower half is loaded with Inert porcelain ball, Inert ceramic ball loading Inert ceramic balls, The old catalyst is loaded on the inert ceramic ball 3, the new catalyst is loaded on the old catalyst, and the new catalyst is loaded on the Inert ceramic balls; new catalyst is loaded at the bottom of the upper section, old catalyst is loaded on the new catalyst, and The inert porcelain ball and adiabatic conversion furnace are provided with an inlet pipe, an outlet pipe and a middle air inlet pipe.

[0007] As a preferred embodiment of the method for simultaneously loading old and new catalysts into the adiabatic conversion furnace of the present invention, the old catalyst is a low-activity cobalt-molybdenum conversion catalyst.

[0008] As a preferred embodiment of the method for simultaneously loading new and old catalysts into the adiabatic conversion furnace of the present invention, the new catalyst is a presulfurized conversion cobalt-molybdenum catalyst.

[0009] As a preferred scheme for the method of simultaneously loading old and new catalysts in the adiabatic conversion furnace described in the present invention, the conventional loading method of the adiabatic conversion furnace is changed, and a part of the old catalyst with good quality after screening is loaded at the bottom of the lower bed layer and the top of the upper bed layer, and an air intake pipe is provided in the adiabatic conversion furnace, and the middle section of the air intake pipe is a DN45015 molybdenum steel pipe.

[0010] As a preferred embodiment of the method for simultaneously loading new and old catalysts in the adiabatic conversion furnace described in the present invention, the loading amount of the new catalyst in the lower half is 1 / 3 to 3 / 5 of the old catalyst.

[0011] As a preferred embodiment of the method for simultaneously loading new and old catalysts into the adiabatic conversion furnace of the present invention, the bulk density of the old catalyst is 0.95-1.20 t / m 3 .

[0012] As a preferred solution of the method for simultaneously loading new and old catalysts in an adiabatic conversion furnace according to the present invention, the crushing strength of the old catalyst is greater than 120N / cm.

[0013] As a preferred solution of the method for simultaneously loading old and new catalysts into the adiabatic conversion furnace of the present invention, the loading amount of the old catalyst is 75% of the loading amount of the new catalyst.

[0014] As a preferred embodiment of the method for simultaneously loading new and old catalysts in an adiabatic conversion furnace according to the present invention, the bottom bed temperature is less than 450°C during the loading process.

[0015] Beneficial effects of the present invention:

[0016] Compared with the original scheme of using new catalysts completely, the present invention increases the loading amount appropriately to ensure that the activity of the catalyst is the same, and fully utilizes the activity potential of the old catalyst at high temperature to maximize economic benefits. At the same time, the old catalyst is fully recycled to reduce the intensity of hazardous waste treatment. After the new and old catalysts are installed, during the initial operation, the temperature of the bottom bed of the catalyst is effectively controlled at about 400-440°C. At the same time, during the gas conduction (gas connection) process of the conversion furnace, the over-temperature phenomenon of each bed temperature is significantly improved (the recovery time after over-temperature is short, generally within 1 minute to return to the normal control range), and the highest temperature is below 490°C, meeting the actual production needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0018] Figure 1 Schematic diagram of the modified loading of the invention.

[0019] In the figure: 1 is the outlet of the conversion furnace, 2 is Φ50mm porcelain ball, 3 is Φ25mm porcelain ball, 4 is catalyst, 5 is new catalyst, 6 is Φ25mm porcelain ball, 7 is the middle entrance of the conversion furnace, 8 is new catalyst, 9 is old catalyst, 10 is Φ25mm porcelain ball, 11 is the upper entrance of the conversion furnace, and 12 is the adiabatic conversion furnace. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0023] Example 1

[0024] This embodiment provides a method for simultaneously loading new and old catalysts into an adiabatic conversion furnace, such as Figure 1 As shown, a general adiabatic conversion furnace includes an adiabatic conversion furnace (12), which is divided into two sections, the bottom of the lower section is filled with Inert ceramic balls (2), Inert ceramic balls (2) are loaded Inert ceramic balls (3), The inert ceramic ball (3) is loaded with a low-activity cobalt-molybdenum-based conversion catalyst (old catalyst) (4), the low-activity cobalt-molybdenum-based conversion catalyst (old catalyst) (4) is loaded with a presulfurized conversion cobalt-molybdenum catalyst (new catalyst) (5), and the presulfurized conversion cobalt-molybdenum catalyst (new catalyst) (5) is loaded with Inert ceramic balls (6); the upper bottom is filled with a presulfurized cobalt-molybdenum conversion catalyst (new catalyst) (8), the presulfurized cobalt-molybdenum conversion catalyst (new catalyst) (8) is filled with a low-activity cobalt-molybdenum conversion catalyst (old catalyst) (9), and the low-activity cobalt-molybdenum conversion catalyst (old catalyst) (9) is filled on top. The inert porcelain ball (10) and the adiabatic conversion furnace (12) are provided with an inlet pipe (11), an outlet pipe (1), and a middle air inlet pipe (7).

[0025] In actual use, because the old catalyst and the new catalyst with certain activation energy are loaded in layers, the conventional adiabatic conversion furnace new catalyst loading method is changed. The raw coal gas enters the catalyst bed from the inlet of the adiabatic conversion furnace, and reacts with the old catalyst appropriately to reduce the concentration of the reaction medium entering the new catalyst, reduce the conversion rate, and realize the control of the hot spot temperature of the upper catalyst. The process gas inlet of the lower catalyst bed is cold-shocked through the middle air inlet pipeline to reduce the reaction activation temperature, increase the space velocity of the lower bed, and use the transition reaction heat of the lower old catalyst layer to effectively control the hot spot temperature of the lower catalyst at a lower level, so as to achieve the purpose of controlling the catalyst bed temperature and extending the service life.

[0026] The mechanical properties in this embodiment were determined according to Q / 0281LCH001-2019;

[0027] Low-activity cobalt-molybdenum shift catalyst (old catalyst) bulk density 0.85~1.10t / m 3 ;

[0028] The crushing strength of low-activity cobalt-molybdenum conversion catalyst (old catalyst) is >120N / cm;

[0029] The low-activity cobalt-molybdenum-based shift catalyst (old catalyst) is Bars;

[0030] New cobalt-molybdenum shift catalyst bulk density 0.95~1.20t / m 3 ;

[0031] The crushing strength of the new cobalt-molybdenum conversion catalyst is ≥130N / cm;

[0032] New cobalt-molybdenum-based shift catalyst Bars;

[0033] The activation energy of the low-activity cobalt-molybdenum conversion catalyst (old catalyst) is no more than 1 / 2 to 3 / 4 of that of the new catalyst under the same conditions.

[0034] Compared with the original scheme of using new catalyst completely, this embodiment appropriately increases the loading amount to ensure that the activity of the catalyst is the same, and fully utilizes the activity potential of the old catalyst at high temperature to maximize economic benefits. At the same time, the old catalyst is fully recycled to reduce the intensity of hazardous waste treatment. After the new and old catalysts are installed, during the initial operation, the temperature of the bottom bed of the catalyst is effectively controlled at about 400-440°C. At the same time, during the gas conduction (gas connection) process of the conversion furnace, the over-temperature phenomenon of each bed temperature is significantly improved (the recovery time after over-temperature is short, generally within 1 minute to return to the normal control range), and the highest temperature is below 490°C, meeting the actual production needs.

[0035] Example 2

[0036] This example is an example in which the old catalyst has not been used before.

[0037] The adiabatic conversion furnace is divided into two sections, the lower section is filled at the bottom Inert ceramic balls, new catalysts are loaded on the inert ceramic balls, and new catalysts are loaded on the Inert ceramic balls, new catalyst is loaded at the bottom of the upper section of the conversion furnace, and new catalyst is loaded on the top Inert ceramic balls, and the new catalyst loading in the upper and lower sections is the same, and air can be introduced into the middle section. The adiabatic conversion furnace with this loading method has low activation energy from top to bottom. In actual application, it is significantly affected by the components and temperature of the raw coal gas. When the effective gas components in the coal gas are high, its low-temperature activity can be used at a lower inlet temperature to control a higher water-gas ratio. However, since it is fully loaded with new catalysts, the carbon monoxide conversion efficiency is high and the heat released is large, causing the catalyst bed of the adiabatic conversion furnace to frequently overheat. During the initial operation of the new catalyst, the temperature of the catalyst bottom bed is around 480°C. During the gas conduction (gas connection) process of the conversion furnace, the temperature of each bed is very likely to exceed 550°C. According to the performance of the cobalt-molybdenum series catalysts When the catalyst temperature is higher than 500℃, the catalyst will sinter, and the bed temperature is too high and the inlet water-gas ratio is insufficient, which can easily lead to methanation reaction and release a large amount of heat, resulting in the out-of-control of the carbon monoxide conversion reaction and an imbalance in the ratio of carbon monoxide and hydrogen at the outlet of the device, leading to excessive venting and increased production costs; when the effective gas component in the coal gas is low, the inlet water-gas ratio of the adiabatic conversion furnace can be reduced and its inlet temperature can be increased to maintain a suitable catalyst bed temperature at a low conversion rate. Long-term operation leads to the gradual loss of low-temperature activity of the new catalyst, increased activation energy, shortened catalyst service life, and increased difficulty in restarting the adiabatic conversion furnace after it is shut down.

[0038] Example 3

[0039] The original design of the adiabatic shift furnace lower section catalyst bottom loading In actual use, the inert ceramic balls have good heat storage capacity. However, due to the small gaps between the ceramic balls and the large gas resistance of the conversion furnace, the initial input pressure difference is higher than 32KPa, which is not conducive to the outward transfer of the conversion reaction heat between the catalysts, resulting in the hot spot temperature of the catalyst being too high during use. After long-term use, the catalyst becomes hardened at high temperature, causing the gas in the lower catalyst to deviate and the pressure difference to rise. In the later period, the pressure difference is higher than 50KPa, which shortens the service life of the catalyst and forces the system to stop and replace the catalyst.

[0040] The catalyst performance, temperature and other data obtained by loading the catalyst according to different loading amounts are recorded in Table 1.

[0041] Table 1 Loading amount and performance data of different new and old catalysts

[0042]

[0043] The above parameters are all actual operating data. The determination of CO conversion rate (activity) refers to the industry standard (QDB Standard 2019)

[0044] It can be seen from Table 1 that the use of old catalysts can ensure the catalytic activity by appropriately increasing the total amount of catalyst.

[0045] In this embodiment, the lower section of the adiabatic conversion furnace adopts and Two specifications of inert ceramic balls are loaded in sections, retaining Inert ceramic balls have good heat storage capacity and use Inert ceramic balls increase the gaps between balls, reduce gas resistance, ensure a larger gas flow rate, and improve the efficiency of heat transfer from the shift reaction. The hot spot temperature of the bottom catalyst is used within the design range of 360°C to 410°C, and the initial pressure difference is 20KPa. The gas distribution effect is good, which alleviates the problem of heat stagnation in the catalyst bed in the original design and extends the service life of the catalyst.

[0046] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for simultaneously loading new and old catalysts in an adiabatic conversion furnace, characterized in that: The adiabatic conversion furnace (12) is divided into an upper section and a lower section. The bottom of the lower section is filled with φ50 inert porcelain balls (2), the φ50 inert porcelain balls (2) are filled with φ25 inert porcelain balls (3), the φ25 inert porcelain balls (3) are filled with old catalysts (4), the old catalysts (4) are filled with new catalysts (5), and the new catalysts (5) are filled with φ25 inert porcelain balls (6); the bottom of the upper section is filled with new catalysts (8), the new catalysts (8) are filled with old catalysts (9), and the old catalysts (9) are filled with φ25 inert porcelain balls (10). The adiabatic conversion furnace (12) is provided with an inlet pipe (11), an outlet pipe (1), and a middle section air intake pipe (7); The old catalyst is a low-activity cobalt-molybdenum-based shift catalyst; The new catalyst is a presulfided conversion cobalt-molybdenum catalyst; The loading amount of the old catalyst is 75% of the loading amount of the new catalyst.

2. The method for simultaneously loading new and old catalysts in an adiabatic conversion furnace according to claim 1, characterized in that: The conventional filling method of the adiabatic conversion furnace is changed, and a part of the old catalyst with good quality after screening is filled at the bottom of the lower bed layer and the top of the upper bed layer, and a middle section air intake pipe (7) is provided in the adiabatic conversion furnace, and the middle section air intake pipe (7) is a DN450 15 molybdenum steel pipe.

3. The method for simultaneously loading new and old catalysts in an adiabatic conversion furnace according to claim 1, characterized in that: The loading amount of the new catalyst loaded in the lower half is 1 / 3 to 3 / 5 of the old catalyst.

4. The method for simultaneously loading new and old catalysts in an adiabatic conversion furnace according to claim 1, characterized in that: The bulk density of the old catalyst is 0.95-1.20 t / m 3 .

5. The method for simultaneously loading new and old catalysts in an adiabatic conversion furnace according to claim 1, characterized in that: The crushing strength of the old catalyst is >120 N / cm.

6. The method for simultaneously loading new and old catalysts in an adiabatic conversion furnace according to claim 1, characterized in that: During the filling process, the bottom bed temperature is less than 450°C.

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