Adiabatic reaction process and system

Abstract

An adiabatic reaction process for generating an aldehyde-containing fluid from an alcohol-containing raw material includes at least two adiabatic reaction units connected in series. The adiabatic reaction units include a first adiabatic reaction unit filled with a first catalyst and a second adiabatic reaction unit filled with a second catalyst. The adiabatic reaction process includes: a step for supplying the alcohol-containing raw material to the first adiabatic reaction unit at a temperature lower than a catalyst limit temperature of the first catalyst and obtaining an intermediate product fluid using the first catalyst; a step for heating the intermediate product fluid flowing out from the first adiabatic reaction unit to a temperature lower than the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction unit; and a step for supplying the heated intermediate product fluid to the second adiabatic reaction unit and obtaining the aldehyde-containing fluid using the second catalyst.

Description

Adiabatic reaction processes and systems

[0001] The present invention relates to an adiabatic reaction process and system for producing an aldehyde-containing fluid from an alcohol-containing feedstock.

[0002] The ETB (Ethanol to Butadiene) process for producing 1,3-butadiene from raw materials containing ethanol can be divided into two processes: a single-stage process (Lebedev process) in which ethanol is converted into butadiene in a single stage, and a two-stage process (Ostromislensky process) in which ethanol is first dehydrogenated to synthesize acetaldehyde, and then butadiene is synthesized from the ethanol and acetaldehyde.

[0003] Example 2 of Patent Document 1 describes a method for an endothermic dehydrogenation reaction of ethanol using multiple adiabatic reaction sections connected in series, in which the inlet temperature is kept constant when the raw material is supplied to the adiabatic reaction section of each stage.

[0004] Special Publication No. 2023-542375

[0005] In the endothermic dehydrogenation reaction of alcohol such as ethanol, when a multi-stage adiabatic reaction section is used, the catalysts in each stage tend to deteriorate at similar times.

[0006] The present invention provides an adiabatic reaction process and system that allows for extended system-wide operating times against catalyst degradation or deactivation.

[0007] As a result of extensive research into solving the above problems, the present inventors have completed the present invention with the following configuration.

[0008] [1] An adiabatic reaction process for producing an aldehyde-containing fluid from an alcohol-containing raw material, comprising at least two adiabatic reaction sections connected in series, the adiabatic reaction sections including a first adiabatic reaction section packed with a first catalyst and a second adiabatic reaction section packed with a second catalyst, the adiabatic reaction process comprising: supplying the alcohol-containing raw material to the first adiabatic reaction section at a temperature lower than the catalytic limit temperature of the first catalyst and obtaining an intermediate product fluid using the first catalyst; heating the intermediate product fluid flowing out of the first adiabatic reaction section to a temperature lower than the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction section; and supplying the heated intermediate product fluid to the second adiabatic reaction section and obtaining the aldehyde-containing fluid using the second catalyst. [2] The adiabatic reaction process according to [1], wherein a pressure drop Δp in the second adiabatic reaction section is smaller than the pressure drop Δp in the first adiabatic reaction section. [3] The adiabatic reaction process according to [1] or [2], comprising: a step of confirming a degree of deterioration of the first catalyst in the first adiabatic reaction section; and a step of, when the degree of deterioration of the first catalyst exceeds a reference range, heating the intermediate product fluid to a temperature that is lower than the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction section and higher than the supply temperature of the intermediate product fluid to the second adiabatic reaction section when the degree of deterioration of the first catalyst is within the reference range, and supplying the intermediate product fluid to the second adiabatic reaction section. [4] The adiabatic reaction process according to any one of [1] to [3], further comprising: a step of confirming a degree of deterioration of the first catalyst in the first adiabatic reaction section; and a step of, when the degree of deterioration of the first catalyst exceeds a reference range, heating the alcohol-containing raw material to a temperature higher than the supply temperature of the alcohol-containing raw material to the first adiabatic reaction section when the degree of deterioration of the first catalyst is within the reference range, and supplying the alcohol-containing raw material to the first adiabatic reaction section; and a step of heating the intermediate product fluid to a temperature lower than the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction section after heating the alcohol-containing raw material and higher than the supply temperature of the intermediate product fluid to the second adiabatic reaction section when the degree of deterioration of the first catalyst is within the reference range, and supplying the intermediate product fluid to the second adiabatic reaction section.[5] The adiabatic reaction process according to any one of [1] to [4], wherein the difference between the catalyst limit temperature of the first catalyst and the supply temperature of the alcohol-containing raw material to the first adiabatic reaction zone is less than 100°C. [6] The adiabatic reaction process according to any one of [1] to [5], wherein the difference between the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction zone and the temperature of the intermediate product fluid supplied to the second adiabatic reaction zone is less than 100°C. [7] The adiabatic reaction process according to any one of [1] to [6], wherein RC1 / RC2 is greater than 1 and not greater than 10, where RC1 is the amount of the first catalyst in the first adiabatic reaction zone and RC2 is the amount of the second catalyst in the second adiabatic reaction zone. [8] The adiabatic reaction process according to any one of [1] to [7], wherein the pressure drop Δp in the second adiabatic reaction zone is 10 to 500 kPa. [9] The adiabatic reaction process according to any one of [1] to [8], wherein L / D in the second adiabatic reaction zone is 0.5 to 5.

[0009]

[10] A system for producing an aldehyde-containing fluid from an alcohol-containing raw material, comprising: a first adiabatic reaction section filled with a first catalyst and producing an intermediate product fluid from the alcohol-containing raw material; a second adiabatic reaction section filled with a second catalyst and producing the aldehyde-containing fluid from the intermediate product fluid; and a heating section disposed between the first adiabatic reaction section and the second adiabatic reaction section, connected in series; the heating section heats the intermediate product fluid flowing out of the first adiabatic reaction section to a temperature lower than the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction section, the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction section being lower than the catalytic limit temperature of the first catalyst, and the temperature of the intermediate product fluid supplied to the second adiabatic reaction section being lower than the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction section.

[11] The system according to

[10] , wherein the amount of the first catalyst packed in the first adiabatic reaction section is greater than the amount of the second catalyst packed in the second adiabatic reaction section.

[12] The system according to

[10] or

[11] , wherein the pressure drop Δp in the second adiabatic reaction section is 10 to 500 kPa.

[0010] The present invention can provide an adiabatic reaction process and system that can extend the operating time of the entire system against catalyst deterioration or deactivation.

[0011] 1 is an explanatory diagram of an adiabatic reaction process and system according to a first embodiment; FIG. 2 is an explanatory diagram of an adiabatic reaction process and system according to a second embodiment;

[0012] Hereinafter, an embodiment for carrying out the present invention will be described.

[0013] 1 shows an explanatory diagram of a system used to carry out an adiabatic reaction process according to the first embodiment. The system 100 according to the first embodiment is a system for producing an aldehyde-containing fluid 22 from an alcohol-containing raw material 20, and includes at least two adiabatic reaction sections 10 connected in series.

[0014] With respect to the direction of fluid flow, the inlet side is the upstream side and the outlet side is the downstream side. In the illustrated example, the upstream side is arranged vertically above and the downstream side is arranged vertically below. The number of stages of adiabatic reaction sections 10 connected in series in the system 100 is not particularly limited, and may be two stages or three or more stages. The adiabatic reaction sections 10 of each stage may be configured using a reactor configured to be adiabatically isolated from the outside.

[0015] The illustrated system 100 includes two or more adiabatic reaction sections 10, including a first adiabatic reaction section 11 located upstream and a second adiabatic reaction section 12 located downstream. The first adiabatic reaction section 11 is filled with a first catalyst 13, which can produce an intermediate product fluid 21 from an alcohol-containing raw material 20. The second adiabatic reaction section 12 is filled with a second catalyst 14, which can produce an aldehyde-containing fluid 22 from the intermediate product fluid 21. The first catalyst 13 and the second catalyst 14 are not particularly limited, but known dehydrogenation catalysts can be used. The first catalyst 13 and the second catalyst 14 may be the same type of catalyst or different types of catalysts. The catalyst may be, but is not particularly limited to, a catalyst containing a transition metal element such as Ni or Pt.

[0016] The catalyst limit temperature is not particularly limited, but may be set as the maximum temperature at which the catalyst can be used in an adiabatic reaction process. For example, it may be at least one selected from the temperature at which the catalyst begins to sinter, the Tammann temperature (the temperature at which metal atoms in the catalyst begin to diffuse through the solid), the temperature at which the catalyst begins to significantly deteriorate, and the upper limit of the recommended temperature range specified by the catalyst manufacturer. When multiple factors are considered in determining the catalyst limit temperature, the lowest temperature among the maximum temperatures set by each factor is used. Furthermore, for safety reasons, the catalyst limit temperature may be determined by subtracting a predetermined temperature from the maximum temperature described above to allow for a safety margin (safety margin). Specific values ​​for the catalyst limit temperature include, for example, 200°C to 600°C, 200°C to 500°C, and 200°C to 400°C. The safety margin is not particularly limited, but may include 5°C, 10°C, 20°C, 50°C, 100°C, and 200°C.

[0017] When the system 100 includes three or more adiabatic reaction sections 10, the upstream of any two consecutive adiabatic reaction sections 10 can be the first adiabatic reaction section 11 and the downstream of the first adiabatic reaction section 11 and the downstream of the second adiabatic reaction section 12. It does not matter whether the first adiabatic reaction section 11 is the most upstream in the system 100. It also does not matter whether the second adiabatic reaction section 12 is the most downstream in the system 100. The first adiabatic reaction section 11 and the second adiabatic reaction section 12 are continuous means that no other adiabatic reaction section 10 is included between them. In the following description, when the first adiabatic reaction section 11 and the second adiabatic reaction section 12 are not to be distinguished from each other, they may be collectively referred to as the adiabatic reaction section 10.

[0018] The alcohol-containing raw material 20 is a fluid containing at least alcohol, and is supplied as a raw material to the first adiabatic reaction section 11. The alcohol-containing raw material 20 may contain an aldehyde produced by dehydrogenation of alcohol. The intermediate product fluid 21 may contain an alcohol or an aldehyde. The aldehyde-containing fluid 22 is a fluid containing an aldehyde produced by dehydrogenation of alcohol. The aldehyde-containing fluid 22 may contain an alcohol. An example of the alcohol is ethanol. An example of the aldehyde is acetaldehyde.

[0019] A heating unit 15 is connected in series between the first adiabatic reaction unit 11 and the second adiabatic reaction unit 12. The heating unit 15 is not particularly limited, and the intermediate product fluid 21 can be heated using a heat exchanger, an electric heater, a furnace (a heating furnace such as an electric furnace), or the like, without the heat medium mixing with the intermediate product fluid 21. The heating unit 15 heats the intermediate product fluid 21 flowing out from the first adiabatic reaction unit 11 to a temperature lower than the temperature of the alcohol-containing raw material 20 supplied to the first adiabatic reaction unit 11. The temperature of the alcohol-containing raw material 20 supplied to the first adiabatic reaction unit 11 is lower than the catalyst limit temperature of the first catalyst 13. In addition, the temperature of the intermediate product fluid 21 supplied to the second adiabatic reaction unit 12 is lower than the temperature of the alcohol-containing raw material 20 supplied to the first adiabatic reaction unit 11.

[0020] The adiabatic reaction process of the first embodiment includes a first reaction step using a first adiabatic reaction section 11, a heating step using a heating section 15, and a second reaction step using a second adiabatic reaction section 12. The first reaction step is a step of supplying an alcohol-containing raw material 20 to the first adiabatic reaction section 11 at a temperature below the catalytic limit temperature of the first catalyst 13 and obtaining an intermediate product fluid 21 using the first catalyst 13. The heating step is a step of heating the intermediate product fluid 21 flowing out from the first adiabatic reaction section 11 to a temperature below the temperature of the alcohol-containing raw material 20 supplied to the first adiabatic reaction section 11. The second reaction step is a step of supplying the intermediate product fluid 21 heated in the heating section 15 to the second adiabatic reaction section 12 and obtaining an aldehyde-containing fluid 22 using the second catalyst 14.

[0021] In the following description, the temperature of the alcohol-containing raw material 20 at the inlet of the first adiabatic reaction section 11 may be referred to as the "inlet temperature of the first adiabatic reaction section 11," the temperature of the intermediate product fluid 21 at the outlet of the first adiabatic reaction section 11 may be referred to as the "outlet temperature of the first adiabatic reaction section 11," the temperature of the intermediate product fluid 21 at the inlet of the second adiabatic reaction section 12 may be referred to as the "inlet temperature of the second adiabatic reaction section 12," and the temperature of the aldehyde-containing fluid 22 at the outlet of the second adiabatic reaction section 12 may be referred to as the "outlet temperature of the second adiabatic reaction section 12."

[0022] In the adiabatic reaction unit 10, a dehydrogenation reaction that produces an aldehyde from an alcohol occurs endothermically and adiabatically. Therefore, the outlet temperature of the first adiabatic reaction unit 11 is lower than the inlet temperature of the first adiabatic reaction unit 11. In addition, the outlet temperature of the second adiabatic reaction unit 12 is lower than the inlet temperature of the second adiabatic reaction unit 12. If the temperature in the adiabatic reaction unit 10 becomes too low, the dehydrogenation reaction becomes difficult to occur, but if the temperature in the adiabatic reaction unit 10 becomes too high, the catalyst becomes more susceptible to deterioration.

[0023] By heating the intermediate product fluid 21 to a temperature lower than the temperature of the alcohol-containing raw material 20 supplied to the first adiabatic reaction unit 11, the dehydrogenation reaction in the second adiabatic reaction unit 12 can be promoted and deterioration of the second catalyst 14 can be suppressed. Furthermore, if the inlet temperatures of the adiabatic reaction units 10 in each stage are the same, the catalysts in each stage tend to deteriorate at the same time, making it impossible for the entire system to operate simultaneously. In contrast, because the inlet temperature of the second adiabatic reaction unit 12 is lower than the inlet temperature of the first adiabatic reaction unit 11, for example, even if deterioration or deactivation of the first catalyst 13 occurs, operation can be continued in the second adiabatic reaction unit 12, thereby extending the operating time of the entire system 100.

[0024] If a certain amount of alcohol is dehydrogenated in the first adiabatic reaction unit 11, the number of moles of alcohol that undergoes the dehydrogenation reaction in the second adiabatic reaction unit 12 is small, resulting in less endothermic heat. Therefore, even if the inlet temperature of the second adiabatic reaction unit 12 is set low enough to prevent deterioration of the second catalyst 14, a desired reaction rate can be achieved.

[0025] In the adiabatic reaction process, a first catalyst confirmation step may be added as a step for confirming the degree of deterioration of the first catalyst 13 in the first adiabatic reaction section 11. When the degree of deterioration of the first catalyst 13 is within the reference range, the first reaction step, the heating step, and the second reaction step may be performed, for example, in the same manner as when the first catalyst confirmation step is not performed, as described above. The first catalyst confirmation step may be performed, for example, by providing an analyzer downstream of the first adiabatic reaction section 11. For example, when the alcohol dehydrogenation reaction is proceeding more slowly than under equilibrium conditions, it may be determined that the degree of deterioration of the first catalyst 13 has exceeded the reference range. Specific examples include (1) when the outlet temperature of the first adiabatic reaction section 11 is higher than the equilibrium temperature, and (2) when the alcohol concentration in the fluid flowing out of the outlet of the first adiabatic reaction section 11 is higher than the equilibrium composition.

[0026] When the degree of deterioration of the first catalyst 13 exceeds the reference range in the first catalyst confirmation step, the inlet temperature of the second adiabatic reaction unit 12 is set higher than the inlet temperature of the second adiabatic reaction unit 12 when the degree of deterioration of the first catalyst 13 is within the reference range, and lower than the inlet temperature of the first adiabatic reaction unit 11. By increasing the inlet temperature of the second adiabatic reaction unit 12, the reaction rate of the second reaction step can be improved so as to compensate for the decrease in the reaction rate of the first reaction step due to deterioration of the first catalyst 13. Specifically, as a result of the heating step, the intermediate product fluid 21 is heated to a temperature that is lower than the temperature of the alcohol-containing raw material 20 supplied to the first adiabatic reaction unit 11 and higher than the supply temperature of the intermediate product fluid 21 to the second adiabatic reaction unit 12 when the degree of deterioration of the first catalyst 13 is within the reference range, and is then supplied to the second adiabatic reaction unit 12.

[0027] 2 shows an explanatory diagram of a system used to carry out an adiabatic reaction process of the second embodiment. The system 200 of the second embodiment has the same configuration as the first embodiment, except that the first heating section 16, the first adiabatic reaction section 11, the second heating section 17, and the second adiabatic reaction section 12 are connected in series in this order. When the system 200 has three or more stages of adiabatic reaction sections 10, as in the first embodiment, the upstream side of any two consecutive stages of adiabatic reaction sections 10 can be the first adiabatic reaction section 11 and the downstream side can be the second adiabatic reaction section 12.

[0028] The second heating section 17 is connected between the first adiabatic reaction section 11 and the second adiabatic reaction section 12. The first heating section 16 is arranged upstream of the first adiabatic reaction section 11. The first heating section 16 heats the alcohol-containing raw material 20 supplied to the first adiabatic reaction section 11 to a temperature lower than the catalytic limit temperature of the first catalyst 13. As with the heating section 15, a heat exchanger, an electric heater, a furnace (a heating furnace such as an electric furnace), or the like can be used as the first heating section 16 and the second heating section 17.

[0029] The adiabatic reaction process of the second embodiment includes a first heating step using the first heating section 16, a first reaction step using the first adiabatic reaction section 11, a second heating step using the second heating section 17, and a second reaction step using the second adiabatic reaction section 12. The first reaction step and the second reaction step can be carried out in the same manner as in the first embodiment. The second heating step of the second embodiment can be carried out in the same manner as the heating step of the first embodiment. The first heating step can be carried out in the first reaction step when the temperature of the alcohol-containing raw material 20 is heated to an appropriate temperature lower than the catalytic limit temperature of the first catalyst 13 before supplying the alcohol-containing raw material 20 to the first adiabatic reaction section 11.

[0030] In the second embodiment, the first catalyst confirmation step can be performed in the same manner as in the first embodiment. In the first catalyst confirmation step performed in the second embodiment, when the degree of deterioration of the first catalyst 13 exceeds the reference range, the inlet temperatures of the first adiabatic reaction unit 11 and the second adiabatic reaction unit 12 are set higher than when the degree of deterioration of the first catalyst 13 is within the reference range, thereby improving the reaction rate of each adiabatic reaction unit 10 so as to compensate for the deterioration of the first catalyst 13.

[0031] Specifically, as a result of the first heating step, the alcohol-containing raw material 20 is heated to a temperature higher than the supply temperature of the alcohol-containing raw material 20 to the first adiabatic reaction unit 11 when the deterioration degree of the first catalyst 13 is within the reference range, and is supplied to the first adiabatic reaction unit 11. Furthermore, as a result of the second heating step, the intermediate product fluid 21 is heated to a temperature lower than the temperature of the alcohol-containing raw material 20 supplied to the first adiabatic reaction unit 11 after heating the alcohol-containing raw material 20 and higher than the supply temperature of the intermediate product fluid 21 to the second adiabatic reaction unit 12 when the deterioration degree of the first catalyst 13 is within the reference range, and is supplied to the second adiabatic reaction unit 12.

[0032] In other words, the catalyst limit temperature of the first catalyst 13 is T １ｃ When the deterioration degree of the first catalyst 13 is within the reference range, the inlet temperature of the first adiabatic reaction section 11 is set to T １ｉ , the inlet temperature of the second adiabatic reaction section 12 is T ２ｉ When the degree of deterioration of the first catalyst 13 exceeds the reference range, the inlet temperature of the first adiabatic reaction section 11 is set to T １ｉ（＋） , the inlet temperature of the second adiabatic reaction section 12 is T ２ｉ（＋） When the degree of deterioration of the first catalyst 13 is within the reference range, it is desirable to satisfy the following relationship: ２ｉ <T １ｉ <T １ｃ When the degree of deterioration of the first catalyst 13 exceeds the reference range, T ２ｉ（＋） <T １ｉ（＋） <T １ｃ Not only that, but also T ２ｉ <T ２ｉ（＋） And T １ｉ <T １ｉ（＋） In summary, it is preferable that T ２ｉ <min(T ２ｉ（＋） , T １ｉ ) ≦ max (T ２ｉ（＋） , T １ｉ ) <T １ｉ（＋） <T １ｃ Here, min represents the minimum value in the parentheses, and max represents the maximum value in the parentheses. ２ｉ（＋） and T １ｉ The magnitude relationship between is arbitrary, and T ２ｉ（＋） <T １ｉ But, T ２ｉ（＋） =T１ｉ But, T ２ｉ（＋） >T １ｉ That's fine too.

[0033] In the first and second embodiments, the pressure loss Δp in the second adiabatic reaction section 12 is preferably smaller than the pressure loss Δp in the first adiabatic reaction section 11. The pressure in the first adiabatic reaction section 11 is determined by the sum of the outlet pressure of the system 100 and the total pressure loss of each section disposed between the first adiabatic reaction section 11 and the outlet of the system 100. Therefore, if the pressure loss in the second adiabatic reaction section 12 is small, the first adiabatic reaction section 11 can be operated at a low pressure. This allows the inlet pressure of the first adiabatic reaction section 11 to be maintained low, the inlet temperature of the first adiabatic reaction section 11 to be lowered, and the life of the first catalyst 13 can be extended.

[0034] As described above, the supply temperature of the alcohol-containing raw material 20 to the first adiabatic reaction section 11 is lower than the catalytic limit temperature of the first catalyst 13. In this case, it is preferable that the difference between the catalytic limit temperature of the first catalyst 13 and the supply temperature of the alcohol-containing raw material 20 to the first adiabatic reaction section 11 is less than 100°C. This makes it possible to relatively increase the reaction rate of the first adiabatic reaction section 11 while suppressing deterioration of the first catalyst 13. When the first catalyst confirmation step and the first heating step are performed in the second embodiment, the temperature is set to 0°C < T １ｃ -T １ｉ If <100°C, then 0°C < T １ｃ -T １ｉ（＋） <100℃ is also valid.

[0035] As described above, the temperature of the intermediate product fluid 21 supplied to the second adiabatic reaction section 12 is lower than the temperature of the alcohol-containing raw material 20 supplied to the first adiabatic reaction section 11. In this case, it is preferable that the difference in temperature between the alcohol-containing raw material 20 supplied to the first adiabatic reaction section 11 and the intermediate product fluid 21 supplied to the second adiabatic reaction section 12 is less than 100°C. This makes it possible to relatively increase the reaction rate of the second adiabatic reaction section 12 while suppressing deterioration of the second catalyst 14. When the first catalyst confirmation step and the first heating step are performed in the second embodiment, 0°C < T １ｉ -T ２ｉ < 100 ° C and 0 ° C < T １ｉ（＋） -T ２ｉ（＋）It is preferred that it is <100°C.

[0036] The pressure drop Δp in the second adiabatic reaction section 12 is preferably 10 to 500 kPa. By suppressing the pressure drop Δp in the second adiabatic reaction section 12, the operating pressure of each adiabatic reaction section 10 can be reduced. The dehydrogenation reaction of alcohol is an equilibrium reaction in which the conversion rate to aldehyde is uniquely determined by temperature and pressure, and is advantageous in that the conversion rate to aldehyde increases as the pressure decreases under constant temperature conditions. Furthermore, the L / D in the second adiabatic reaction section 12 is preferably 0.5 to 5. In this case, since this is within a general design range, there is a high degree of freedom in design. Furthermore, the pressure drop Δp in the second adiabatic reaction section 12 described above can be more easily achieved.

[0037] It is preferable that the catalyst amount (RC1) of the first catalyst 13 packed in the first adiabatic reaction section 11 is greater than the catalyst amount (RC2) of the second catalyst 14 packed in the second adiabatic reaction section 12. If the temperature of the alcohol-containing raw material 20 supplied to the first adiabatic reaction section 11 is higher than the temperature of the intermediate product fluid 21 supplied to the second adiabatic reaction section 12, the first catalyst 13 is more likely to deteriorate and be deactivated than the second catalyst 14; however, if RC1 is increased, the first adiabatic reaction section 11 can be operated for a longer period of time.

[0038] When the amount of the first catalyst 13 in the first adiabatic reaction section 11 is RC1 and the amount of the second catalyst 14 in the second adiabatic reaction section 12 is RC2, it is preferable that RC1 / RC2 is greater than 1 and not greater than 10. This allows the operation of the first adiabatic reaction section 11 to be continued for a longer period of time using the downstream first catalyst 13, even if the first catalyst 13 deteriorates or is deactivated from the upstream side within the first adiabatic reaction section 11. If RC1 / RC2 is too large, the pressure loss in the first adiabatic reaction section 11 increases, and as described above, the inlet pressure of the first adiabatic reaction section 11 increases, making it difficult to lower the inlet temperature of the first adiabatic reaction section 11 and making the first catalyst 13 more susceptible to deterioration. Specific values ​​for RC1 / RC2 are within the range of greater than 1 and not greater than 10, such as 1.1, 1.2, 1.5, 2, 5, 10, etc., or appropriate values ​​within a range defined by any two of these points as upper and lower limits.

[0039] The above-described systems 100 and 200 and adiabatic reaction processes can be used for dehydrogenation reactions, such as producing acetaldehyde from ethanol. Furthermore, acetaldehyde-containing fluids can also be used in the ETB reaction, which synthesizes 1,3-butadiene from ethanol and acetaldehyde. The ethanol-containing raw material can also include bioethanol and recycled ethanol obtained using recycling technologies for biomass, waste plastics, waste tires, etc. The systems 100 and 200 may be an adiabatic reaction unit in which two or more adiabatic reaction sections 10 are connected in series. Units for performing other reactions or processes may be included upstream, downstream, or around the systems 100 and 200. The other reactions or processes can be added either before or after the adiabatic reaction.

[0040] If one or more of the adiabatic reaction units 10 in each stage become unusable due to catalyst deactivation or the like, only the adiabatic reaction units 10 whose catalysts are not deactivated may be connected in series to continue operation. For example, when the first adiabatic reaction unit 11 is stopped, the alcohol-containing raw material 20 may be supplied to the second adiabatic reaction unit 12. When the second adiabatic reaction unit 12 is stopped, the fluid flowing out from the first adiabatic reaction unit 11 may be supplied as the aldehyde-containing fluid 22 to a subsequent reaction or treatment.

[0041] When the systems 100, 200 include three or more stages of adiabatic reaction sections 10, the above-described relationship between the first adiabatic reaction section 11 and the second adiabatic reaction section 12 may be adopted in at least some of the sets (number of sets = number of stages - 1) of two consecutive adiabatic reaction sections 10. The above-described relationship between the first adiabatic reaction section 11 and the second adiabatic reaction section 12 may be adopted in all or most (majority) of the sets of adiabatic reaction sections 10.

[0042] The systems 100 and 200 may include a control unit (not shown) for controlling the temperature and the like. The control unit may include an input device, a recording device, a calculation device, an output device, and the like. Examples of the control unit include a computer and a controller. Information can be transmitted between the control unit and each unit (sensor, etc.) within the systems 100 and 200 or the outside, using wired communication, wireless communication, tags, recording media, or other means.

[0043] In Examples 1 to 5, as shown in FIG. 1 or 2, a system having a two-stage adiabatic reaction section 10 consisting of a first adiabatic reaction section 11 and a second adiabatic reaction section 12 was used to simulate an adiabatic reaction process for producing an acetaldehyde-containing fluid from an ethanol-containing raw material. In Comparative Example 1, the adiabatic reaction section 10 was one stage. The simulation conditions were as follows: WHSV of raw material ethanol (EtOH) = 1 hr －１ Mass flow rate of raw material ethanol (EtOH) = 25,550 kg / hr. Inlet pressure 0.5 MPaG. Reaction tube diameter 2,600 mm.

[0044]

[0045] The reaction stabilization distance shown in Table 1 is the catalyst layer distance (length in the fluid flow direction) from the raw material supply port when the temperature change before and after the catalyst layer is 0.0001°C or less when the catalyst layer is divided into 170 sections. Each stage should be provided with a catalyst that is equal to or greater than the reaction stabilization distance. If the reaction stabilization distance in the second stage is short, a smaller amount of catalyst is required in the second adiabatic reaction section 12. A dehydrogenation catalyst with a catalyst light-off temperature of 200°C was used as the catalyst in each stage. The catalyst light-off temperature is the lowest temperature at which the catalytic reaction can start. The final molar ratio shown in Table 1 is the molar ratio of aldehyde / (alcohol + aldehyde) in the aldehyde-containing fluid. It was confirmed that even when the number of reaction stages is two and the inlet temperature of the second stage is lowered, the dehydrogenation reaction can be stabilized at a final molar ratio equivalent to that in the case of a single stage.

[0046] The present invention can be utilized in an adiabatic reaction process for producing an aldehyde-containing fluid from an alcohol-containing feedstock.

[0047] 10...adiabatic reaction section, 11...first adiabatic reaction section, 12...second adiabatic reaction section, 13...first catalyst, 14...second catalyst, 15...heating section, 16...first heating section, 17...second heating section, 20...alcohol-containing raw material, 21...intermediate product fluid, 22...aldehyde-containing fluid, 100, 200...system.

Claims

1. An adiabatic reaction process for producing an aldehyde-containing fluid from an alcohol-containing raw material, comprising at least two adiabatic reaction sections connected in series, the adiabatic reaction sections including a first adiabatic reaction section packed with a first catalyst and a second adiabatic reaction section packed with a second catalyst, the adiabatic reaction process comprising: a step of supplying the alcohol-containing raw material to the first adiabatic reaction section at a temperature lower than the catalytic limit temperature of the first catalyst and obtaining an intermediate product fluid using the first catalyst; a step of heating the intermediate product fluid flowing out from the first adiabatic reaction section to a temperature lower than the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction section; and a step of supplying the heated intermediate product fluid to the second adiabatic reaction section and obtaining the aldehyde-containing fluid using the second catalyst.

2. The adiabatic reaction process according to claim 1, wherein the pressure drop Δp in the second adiabatic reaction section is smaller than the pressure drop Δp in the first adiabatic reaction section.

3. The adiabatic reaction process according to claim 1, comprising: a step of confirming a degree of deterioration of the first catalyst in the first adiabatic reaction section; and a step of, when the degree of deterioration of the first catalyst exceeds a reference range, heating the intermediate product fluid to a temperature that is lower than the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction section and higher than the supply temperature of the intermediate product fluid to the second adiabatic reaction section when the degree of deterioration of the first catalyst is within the reference range, and supplying the intermediate product fluid to the second adiabatic reaction section.

4. The adiabatic reaction process according to claim 1, further comprising: a step of confirming a degree of deterioration of the first catalyst in the first adiabatic reaction section; and, when the degree of deterioration of the first catalyst exceeds a reference range, a step of heating the alcohol-containing raw material to a temperature higher than a supply temperature of the alcohol-containing raw material to the first adiabatic reaction section when the degree of deterioration of the first catalyst is within the reference range, and supplying the alcohol-containing raw material to the first adiabatic reaction section; and a step of heating the intermediate product fluid to a temperature lower than a temperature of the alcohol-containing raw material supplied to the first adiabatic reaction section after heating the alcohol-containing raw material and higher than a supply temperature of the intermediate product fluid to the second adiabatic reaction section when the degree of deterioration of the first catalyst is within the reference range, and supplying the intermediate product fluid to the second adiabatic reaction section.

5. The adiabatic reaction process according to claim 1, wherein the difference between the catalytic limit temperature of the first catalyst and the supply temperature of the alcohol-containing raw material to the first adiabatic reaction section is less than 100°C.

6. The adiabatic reaction process according to claim 5, wherein the difference between the temperature of the alcohol-containing feedstock supplied to the first adiabatic reaction section and the temperature of the intermediate product fluid supplied to the second adiabatic reaction section is less than 100°C.

7. The adiabatic reaction process according to claim 1, wherein RC1 / RC2 is greater than 1 and less than or equal to 10, where RC1 is the amount of the first catalyst in the first adiabatic reaction section and RC2 is the amount of the second catalyst in the second adiabatic reaction section.

8. The adiabatic reaction process according to claim 1, wherein the pressure drop Δp in the second adiabatic reaction section is 10 to 500 kPa.

9. The adiabatic reaction process according to claim 1, wherein the L / D ratio in the second adiabatic reaction section is 0.5 to 5.

10. A system for producing an aldehyde-containing fluid from an alcohol-containing raw material, comprising: a first adiabatic reaction section packed with a first catalyst and producing an intermediate product fluid from the alcohol-containing raw material; a second adiabatic reaction section packed with a second catalyst and producing the aldehyde-containing fluid from the intermediate product fluid; and a heating section disposed between the first adiabatic reaction section and the second adiabatic reaction section, connected in series; wherein the heating section heats the intermediate product fluid flowing out from the first adiabatic reaction section to a temperature that is lower than the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction section; and wherein the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction section is lower than the catalyst limit temperature of the first catalyst, and the temperature of the intermediate product fluid supplied to the second adiabatic reaction section is lower than the temperature of the alcohol-containing raw material supplied to the first adiabatic reaction section.

11. The system according to claim 10, wherein the catalytic amount of the first catalyst packed in the first adiabatic reaction section is greater than the catalytic amount of the second catalyst packed in the second adiabatic reaction section.

12. The system according to claim 10, wherein the pressure drop Δp in the second adiabatic reaction section is 10 to 500 kPa.

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