KR101286407B1 - Fluidized bed reaction device and method of gas phase exothermic reaction by using the same - Google Patents

Abstract

In the present invention, when the gas phase exothermic reaction is carried out using a fluidized bed reactor having a heat removing tube therein, the vapor phase heat generation satisfies the process stability and economic efficiency by efficiently distributing the vapor in the heat removing tube and controlling the temperature of the reactor. It is an object to provide a reaction method.

A method of supplying a reaction raw material to a fluidized bed reactor having a plurality of heat removal tubes therein, and performing a gas phase exothermic reaction, comprising: (a) a first vapor and / or a material constituting the first steam in one of the heat removal tubes; Distributing a liquid to defrost the fluidized bed reactor and generating superheated steam from the first vapor and / or the liquid; and (b) contacting the superheated vapor with a liquid of a material constituting the first vapor. And a step of generating steam, and (c) circulating the second steam inside another heat removing tube.

Description

Fluidized bed reaction apparatus and gas phase exothermic reaction method using the same {FLUIDIZED BED REACTION DEVICE AND METHOD OF GAS PHASE EXOTHERMIC REACTION BY USING THE SAME}

The present invention relates to a fluidized bed reaction apparatus having a heat removal tube and a gas phase exothermic reaction method using the same.

Fluidized bed technology has been applied to various manufacturing techniques since its development in the late 19th century. Main industrial applications of the fluidized bed include coal gasification furnaces such as FCC plants, acrylonitrile production plants by ammoxidation of propylene, polyethylene gas phase polymerization plants, and maleic anhydride production plants. The fluidized bed reactor can be easily removed or added to the reaction heat, and thus, the fluidized bed reactor can be maintained at a uniform temperature in the bed, and can be treated with a high concentration gas in the explosion range. Application, improvement is expected.

The fluidized bed reactor that performs the gas phase exothermic reaction has a heat removal tube therein, and removes the heat of reaction by circulating water or steam to control the reaction temperature.

As an invention relating to a heat removal tube provided inside a fluidized bed reactor, for example, Patent Document 1 discloses a lean bed temperature of a fluidized bed reactor when the aliphatic hydrocarbon having 4 or more carbon atoms is supplied to the fluidized bed reactor to produce maleic anhydride by gas phase oxidation reaction. A method of producing maleic anhydride with high yield and stably by providing a heat removal tube so as to be lower than the rich bed temperature is disclosed.

In addition, Patent Literature 2 discloses an arrangement of a heat exchange tube that removes heat and / or provides heat in a fluidized bed reactor.

Further, Patent Document 3 describes a method of precisely controlling the reaction temperature by using a heat removal tube for supplying a refrigerant at a normal speed and a heat removal tube for supplying a refrigerant at a variable speed.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2-19370

[Patent Document 2] Japanese Unexamined Patent Publication No. 2002-213886

[Patent Document 3] International Publication No. 95/21692 Pamphlet

The reaction temperature is one of the important control factors when operating the fluidized bed reactor. Stabilization of reaction temperature is an essential matter from the standpoint of keeping the yield of the desired product high and from the viewpoint of safe operation. In addition, the by-product steam from the fluidized bed reactor is used for important purposes, and in an industrial scale manufacturing plant, the efficient use of steam greatly depends on economics, of course. However, there is still room for improvement for the method of cooling a fluidized bed reactor that satisfies both process stability and economy.

The present invention relates to a gas phase exothermic reaction method that satisfies process stability and economic efficiency sufficiently by circulating vapor in a heat exchanger tube and efficiently controlling the temperature of the reactor when the gas phase exothermic reaction is performed using a fluidized bed reactor having a heat exchanger tube therein. It is an object to provide a fluidized bed reaction apparatus.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining the method to distribute steam stably and economically as a refrigerant | coolant to the heat exchanger tube of a fluidized bed reactor, this inventor discovered that this subject could be solved and reached | attained this invention.

That is, this invention is a gas-phase exothermic reaction method and a fluidized bed reaction apparatus as described below.

[1] A method of supplying a reaction raw material to a fluidized bed reactor including a plurality of heat removing tubes therein and performing gas phase exothermic reaction, comprising: (a) a first steam and / or the first inside the one heat removing tube; Circulating a fluidized bed reactor by circulating a liquid of a substance constituting steam, and generating superheated steam from the first steam and / or the liquid; and (b) a substance constituting the first steam in the superheated steam. And a step of contacting the liquid of said second vapor to produce second vapor, and (c) circulating said second vapor into another of said heat removal tubes.

[2] The gas phase exothermic reaction method according to [1], wherein the reaction raw material contains alkanes and / or alkenes having 2 to 4 carbon atoms.

[3] The gas phase exothermic reaction method of [2], wherein the alkane is propane and / or isobutane.

[4] The gas phase exothermic reaction method of [2], wherein the alkene is propylene and / or isobutylene.

[5] The gas phase exothermic reaction method according to any one of [1] to [4], wherein the gas phase exothermic reaction is an ammoxidation reaction.

[6] A fluidized bed reaction apparatus for vapor phase exothermic reaction having a fluidized bed reactor, a plurality of heat removal tubes disposed therein, and a desuperheater connected to one of the heat removal tubes and the other heat removal tubes, wherein (a) the One heat pipe circulates a liquid of a first vapor and / or a material constituting the first steam therein to defrost the fluidized bed reactor and generate superheated steam from the first vapor and / or the liquid. (B) the desuperheater is to contact the superheated steam with a liquid of a substance constituting the first steam to generate a second steam, and (c) the other heat pipe is configured to provide the second steam. A fluidized bed reaction apparatus for circulating therein.

[7] The fluidized bed reactor according to [6], wherein a plurality of the heat removing tubes are arranged to satisfy the condition represented by the following formula (1).

0.70 S _max ≤S _min (1)

[In Formula (1), S _max represents four areas in the imaginary plane passing through the center of the cross section substantially orthogonal to the flow direction of the reaction raw material and the reaction product in the fluidized bed reactor and orthogonal to the cross section. Up represents the largest outer surface area total value of the outer surface area total value of the first yeolgwan in each of the areas, S _min is the smallest outer surface area of the outer surface area total value of the first yeolgwan in each of the regions in the case of Represents the total value.]

[8] [6] or [7], wherein, among the plurality of heat removal tubes, the external surface area of the other heat removal tubes is 1 to 10 times based on the external surface area of the heat removal tube having a minimum external surface area. Fluidized bed reaction apparatus.

According to the present invention, in the gas phase exothermic reaction using a fluidized bed reactor having a heat removal tube therein, the vapor phase exothermic reaction method satisfies the process stability and economy sufficiently by effectively circulating steam in the heat removal tube and controlling the temperature of the reactor. Fluidized bed reaction apparatus can be provided.

EMBODIMENT OF THE INVENTION Hereinafter, the best form (henceforth simply "this embodiment") for implementing this invention is demonstrated in detail, referring drawings as needed. In addition, the same code | symbol is attached | subjected to the same element in drawing, and the overlapping description is abbreviate | omitted. In addition, the positional relationship of up, down, left, right, etc. shall be based on the positional relationship shown in drawing unless there is particular problem. In addition, the dimension ratio of an apparatus and a member is not limited to the ratio shown.

The gas phase exothermic reaction method of the present embodiment is a method of supplying a reaction raw material to a fluidized bed reactor having a plurality of heat exchanger tubes therein, and performing a gas phase exothermic reaction, which comprises (a) water vapor and / or water in one of the heat exchanger tubes. Dispersing the fluidized bed reactor to generate superheated steam from the water vapor and / or water, (b) contacting the superheated water with water to produce water vapor, and the steam inside the other heat removing tube. It has a process to distribute to.

1 is a schematic diagram conceptually showing an example of a fluidized bed reaction apparatus having a plurality of heat removing tubes of the present embodiment. This fluidized bed reaction apparatus is used for a gas phase exothermic reaction, and has a fluidized bed reactor 9 and a heat removing system having a plurality of heat removing tubes disposed therein. The heat removal system is specifically connected to the cooling coil 2, the superheat coil 3, the steam coils 4, 5, 6, the gas-liquid separation container 1, and the some steam coil which are respectively a heat removal tube, respectively. Desuper heaters 7 and 8 are provided. The fluidized bed reactor 9 may be the same as that known in the art. For example, the fluidized bed reactor 9 has a dispersion pipe and / or a dispersion plate of a gas, which is a reaction raw material, at the bottom thereof, and collects a catalyst mixed in the reaction gas flowing out of the reactor at the top thereof. It may have a cyclone. In this case, the reaction raw materials and reaction products are generally circulated from below.

The reaction raw material is supplied to the fluidized bed reactor 9 in which the required amount of the fluidized bed catalyst is filled via a raw material supply pipe (not shown) connected from the lower side of the fluidized bed reactor 9. The heat generated by the gas phase exothermic reaction is removed by cooling in the coils 2, 3, 4, 5, and 6, which are heat removal tubes provided in the fluidized bed reactor 9, and the reaction temperature is controlled.

The gas phase exothermic reaction is not particularly limited, and examples thereof include oxidation reactions, ammoxidation reactions, and alkylation reactions.

The reaction raw material is not particularly limited as long as it is a raw material for gas phase exothermic reaction, and examples thereof include alkanes, alkenes, alcohols, and aromatic hydrocarbons. Specifically, in the ammoxidation reaction, organic compounds such as hydrocarbons, oxidants such as oxygen and air, and ammonia are used as reaction raw materials. Alkanes and alkenes are mentioned as an example of hydrocarbon which becomes one of the raw materials of ammoxidation reaction. An organic compound and an oxidizing agent are used individually by 1 type or in combination of 2 or more types, respectively.

Examples of alkanes include those having 1 to 4 carbon atoms (methane, ethane, propane, n-butane, isobutane), and examples of alkenes having 2 to 4 carbon atoms (ethylene, propylene, n-butylene, isobutylene, and t). -Butylene). In these, propane and / or isobutane as an alkane, and propylene and / or isobutylene are preferable as an alkane from a viewpoint of the value as a chemical intermediate material of the nitrile compound to produce | generate.

The catalyst for the gas phase exothermic reaction charged in the fluidized bed reactor is not particularly limited as long as it is a solid catalyst usually used in the reaction. Examples thereof include metal oxide catalysts supported on silica and the like.

Water of saturation temperature is supplied from the gas-liquid separation vessel 1 to the cooling coil 2 using the pump 1a. Water pressure in the cooling coil ^{(2), 20 kg / ㎝ 2 G~60 kg} / ㎝ 2 G is preferable, and more preferably ^{25 kg / ㎝ 2 G~50 kg /} ㎝ 2 G.

The cooling coil 2 is heat-reduced in the fluidized bed reactor 9 by latent heat of evaporation of water of saturation temperature, and is arrange | positioned in multiple series in 1 series or parallel in the inside of the reactor 9. Although the example of the 1 series of cooling coil which consists of a straight pipe | tube part and a U-shaped bend part is shown in FIG. 1, a cooling coil is not limited to this form. One end of the cooling coil 2 is connected to a line through which water sent from the pump 1a flows through the wall of the fluidized bed reactor 9. The cooling coil 2 is bent to the bottom of the reactor at the bend and further bent to be reversed upward at the bend via the straight pipe. This is called a pass. The cooling coil 2 in FIG. 1 is an example of three passes. The cooling coil 2 is connected with the line connected to the gas-liquid separation container 1 at the other end. This series is called a series, and a plurality of series of cooling coils 2 are preferably provided. In the present invention, when a plurality of series of heat removing tubes are provided, each series of heat removing tubes is one heat removing tube, and the plurality of series of heat removing tubes is composed of a plurality of heat removing tubes.

As for the coil diameter of the cooling coil 2, 20 mm-200 mm and the length Lc of a straight pipe part on the basis of an outer diameter, it is preferable that Lc / Lr is a length which becomes 0.05-0.8, when the reactor length is Lr. More preferably, Lc / Lr is 0.2-0.7. It is preferable that the number of passes of the cooling coil 2 is 1-10 passes. The material of the cooling coil 2 can employ | adopt the steel pipe prescribed | regulated to JISG-3458, and the elbow tube prescribed | regulated to JISB-2311, for example, and will not specifically limit, if the conditions of use of temperature and pressure are satisfied.

The water flowing in the cooling coil 2 is heated due to the exothermic reaction in the fluidized bed reaction vessel 9, and at least part of it evaporates. As for the amount of water vapor generated by this evaporation, it is preferable that the evaporation rate Rv calculated by following formula (2) becomes 5%-30%.

Rv = (mass of water vapor) / [mass of water supplied to cooling coil (2)] × 100 (2)

Moreover, it is preferable that the cooling coil 2 is in charge of 70%-95% of heat removal of the required amount of heat removal Qc calculated by following formula (3).

Qc = Qr- (Qe-Qi) -Qd (3)

In the formula (3), Qc is the required heat removal amount, Qr is the reaction calorific value of the gas phase exothermic reaction in the reactor 9, Qe is the sensible heat amount of the gas flowing out of the reactor 9, and Qi is the reactor 9 The sensible heat amount and Qd of the source gas to be supplied represent the heat dissipation amount in the reactor 9, respectively, and the units of each heat amount are the same.

Water vapor and water generated in the cooling coil 2 are returned to the gas-liquid separation vessel 1 via a line connected to the other end of the cooling coil 2, and water vapor is taken out from the upper portion of the gas-liquid separation vessel 1. For level adjustment of the gas-liquid separation vessel 1, water is supplied to the gas-liquid separation vessel 1 from a line not shown.

The water vapor (high pressure steam) taken out from the gas-liquid separation vessel 1 is supplied via line 10 to other equipment that requires high pressure steam, for example. It is also possible, if necessary, to supply the required amount of high pressure steam to the superheat coil 3 installed in the fluidized bed reactor 9 via a line branching from line 10. The superheat coil 3 can have the same specifications as the cooling coil 2 except for distributing the high pressure steam therein and removing the inside of the fluidized bed reactor 9 by the sensible heat change of the steam. It is preferable that the superheat coil 3 is in charge of 0% to 15% of the required heat removal amount Qc. The high pressure steam superheated in the superheat coil 3 is returned to the line 10 through a different line branched from the line 10 above.

The surplus of the high pressure steam taken out from the gas-liquid separation vessel 1 is supplied to the steam coil 4 via the line 11 branched from the line 10, and the desuperheater 7, the steam coil 5, the desuper It is further distributed to the heater 8 and the steam coil 6. The excess high pressure steam flowing through the line 11 is, for example, 5% to 50% of the total amount of water vapor generated from the gas-liquid separation vessel 1. If necessary, such as when there is a lack of water vapor, high pressure water vapor may be introduced from the outside via line 12.

The high pressure steam from the line 11 is first supplied to the steam coil 4 via the line 11a. Although the steam coil 4 may be one series, it is more preferable if a series is provided in order to reduce the fluctuation | variation of the reaction temperature of gaseous-phase exothermic reaction in the fluidized-bed reactor 9, and to achieve uniform reaction progression. One end and the other end of the steam coil 4 are connected with the line 11a and the line 13 in the wall part of the fluidized-bed reaction container 9, respectively.

The coil diameter of the steam coil 4 is preferably 20 mm to 200 mm based on the outer diameter, and the length Lv4 of the straight pipe portion is a length such that Lv4 / Lr is 0.05 to 0.8 when the reactor length is Lr. More preferably, Lv4 / Lr is 0.2-0.7. It is preferable that the number of passes of the steam coil 4 is 1-10 passes. The material of the steam coil 4 can employ | adopt the steel pipe prescribed | regulated to JISG-3458, and the elbow tube prescribed | regulated to JISB-2311, and if a use condition of temperature and pressure is satisfied, it will not specifically limit.

A part of the high pressure steam from the line 11 may be supplied to the desuperheater 7 via the line 11b provided to bypass the steam coil 4. The amount of high pressure steam flowing through each of the lines 11a and 11b (the balance between the supply amount of the high pressure steam to the steam coil 4 and the amount of the high pressure steam bypassing the steam coil 4) is adjusted to adjust the temperature in the fluidized bed reactor 9. It is preferred if it is controlled. For example, the amount of high pressure steam flowing in the steam coil 4 in line 11a may be manually controlled with reference to the temperature indicated by at least one thermometer installed in the reactor 9. Alternatively, the amount of water vapor flowing through the line 11a may be automatically controlled so that the temperature in the reactor 9 becomes the target temperature. In the case of automatically controlling the amount of steam, the amount of steam flowing in the steam coil 4 may be controlled by full opening / complete closing of the steam coil flowing in the steam coil 4 so as to be a set target temperature, or line 11a. And / or a flow control valve (not shown) provided in line 11b. The flow rate control of the water vapor flowing through the steam coil 4 is preferably performed frequently. This flow rate control is preferably performed at least once per hour, preferably at least once every 30 minutes.

The thermometer is not particularly limited as long as it is a normal one used in a chemical plant. It is preferable to install a thermometer in the several place which can grasp | ascertain the temperature distribution of a catalyst layer. If the height of the fluidized bed reactor 9 is Lr, the number of installation of the thermometer is preferably in the range of 0.1 Lr to 0.5 Lr from the lower end of the reactor 9 and 0.01 to 10 per 1 m ³ of the volume of the reactor 9. Do.

The high pressure steam flowing in the steam coil 4 is heated due to the exothermic reaction in the fluidized bed reactor 9 and becomes superheated steam to further distribute the line 13. This superheated steam and the high pressure steam which bypassed the steam coil 4 join and are supplied to the desuperheater 7.

Di pressure in the super-heater (7) is for example set to ^{2 kg / ㎝ 2 ~8 kg /} ㎝ 2 lower pressure than the pressure of the gas-liquid separating vessel (1). In the desuperheater 7, the pump 7a is used to circulate the water by the spray circulation method, make countercurrent contact with the supplied water vapor, evaporate a part of the water to generate water vapor, and increase the temperature of the superheated water vapor. Lowers. It is preferable that the temperature at the time of supplying the circulating water to the desuperheater 7 by spraying is a saturation temperature of water ± 3 ° C. The desuperheater 7 is supplied with water through a line (not shown) from the outside. By lowering the temperature of the superheated steam by the desuperheater, the temperature difference between the steam and the reaction temperature is maintained to some extent and can be reused as a refrigerant.

The water vapor cooled by the desuperheater 7 is taken out from the top of the desuperheater 7 and supplied to the steam coil 5. The steam taken out from the desuperheater 7 may be directly supplied to the desuperheater 8 by bypassing the steam coil 5. The specifications of the steam coil 5 (connection with a line, the number of series, the coil diameter, the length of the straight pipe, the number of passes, the material, etc.) may be the same as the specifications of the steam coil 4. In addition, the balance between the amount of steam supplied to the steam coil 5 and the amount of steam bypassing the steam coil 5 is equal to the amount of high pressure steam supplied to the steam coil 4 and the amount of high pressure steam bypassing the steam coil 4. The control may be performed in the same manner as in the balance of. The water vapor flowing in the steam coil 5 is heated due to the exothermic reaction in the fluidized bed reactor 9 to become superheated water vapor. This superheated steam and the steam which bypassed the steam coil 5 join and are supplied to the desuperheater 8.

The pressure in the desuperheater 8 is set to, for example, a pressure 2 kg / cm ^{2 to} 8 kg / cm ² lower than the pressure of the desuperheater 7. In the desuperheater 8, the pump 8a is used to circulate water by the spray circulation system, to make countercurrent contact with the supplied water vapor, and to reduce the temperature of the superheated water vapor by evaporating a part of the water. It is preferable that the temperature at the time of supplying the desuperheater 8 of the water to circulate by spray is made into the saturation temperature of water +/- 3 degreeC. The desuperheater 8 is supplied with water through a line (not shown) from the outside. By lowering the temperature of the superheated steam by the desuperheater, the temperature difference between the steam and the reaction temperature is maintained to some extent and can be reused as a refrigerant.

The water vapor cooled by the desuperheater 8 is taken out from the top of the desuperheater 8 and supplied to the steam coil 6. In addition, the steam taken out from the desuperheater 8 may bypass the steam coil 6. The specifications of the steam coil 6 (connection with the line, the number of series, the coil diameter, the length of the straight pipe portion, the number of passes, the material, etc.) may be the same as the specifications of the steam coil 4. In addition, the balance between the amount of steam supplied to the steam coil 6 and the amount of steam bypassing the steam coil 6 is equal to the amount of high pressure steam supplied to the steam coil 4 and the amount of high pressure steam bypassing the steam coil 4. The control may be performed in the same manner as in the balance of. The water vapor flowing in the steam coil 6 is heated due to the exothermic reaction in the fluidized bed reactor 9 and becomes superheated water vapor. This superheated steam and the steam which bypassed the steam coil 6 merge and are supplied to other equipment which requires, for example, low to medium pressure steam.

The above-mentioned steam coils 4, 5, 6 are in charge of 5% to 20% of the required heat removal amount Qc, for example.

FIG. 2: is a figure for demonstrating arrangement | positioning of said each coil (heat removal tube) in the fluidized-bed reactor 9 which concerns on this embodiment. This FIG. 2 is a schematic diagram which shows the position where each said coil exists when the inside of the reactor 9 is seen from the S direction of FIG.

2 is a diagram schematically illustrating the presence position of the coils and the outer surface area of each coil in the fluidized bed reactor 9 using a mass, and is orthogonal to the S direction at a specific height of the reactor 9. The cross section (hereinafter, simply referred to as "cross section") is not shown. Also, depending on the height position of the reactor 9, the shape of the cross section is different, but FIG. 2 is inherent to the reactor 9. One mass represents the unit area of the outer surface area, and a plurality of mutually contacting masses constitute a single coil. The outer surface area ratio of each coil is expressed as the sum of the masses in contact with each other. In addition, the area indicated by the mass shows the present position of each coil in the reactor 9. It is preferable that the outer surface area of the other coils is 1 to 10 times, and more preferably 1 to 5 times, based on the outer surface area of the coil having the minimum outer surface area as a reference (1 mass). In the comparison of the outer surface area, the types of cooling coils, superheat coils, and steam coils are not distinguished, and the outer surface area of all other coils is several times that of the coils based on the outer surface area of the coil having the smallest outer surface area among all coils. Compare cognition. In FIG. 2, the minimum outer surface area is 1 mass, and the outer surface area of each coil is in the range of 1 to 10 masses, with the outer surface area of the coil having the minimum outer surface area as a reference (1 mass). The condition that the outer surface areas of the other coils are 1 to 10 times respectively is satisfied.

In addition, four regions (0 ° to 90 °, 90 ° to 180 °, 180 ° to 270 °, and 270 ° to 0) are defined by a virtual plane passing through the center of the cross section. (Shown in fan shape in FIG. 2). Of the total external surface area values of the coils present in each region, when the maximum one is S _max and the minimum one is S _min , S _max and S _min are represented by the following formula (1);

It is preferable to satisfy 0.70 S _max ≤ S _min (1). In the formula (1), S _{max divides} the fluidized bed reactor into four regions in an imaginary plane passing through the center of the cross section substantially orthogonal to the flow direction of the reaction raw materials and the reaction product therein and orthogonal to the cross section. for, represents the largest outer surface area total value of the total outer surface area value of the yeolgwan in each area, S _min shows a smallest value of the total outer surface area of the outer surface area total value yeolgwan in each region.

When S _max and S _min satisfy the above formula (1), the heat removal that can be ensured in each zone is less than 30% even when comparing the maximum and the minimum, and the difference in the amount of heat removal in each zone is relatively small. MEANS TO SOLVE THE PROBLEM This inventor discovered that in the fluidized bed reaction, the heat | fever exchange | transformed in the horizontal direction (horizontal direction) is small between the gas which flows through a reactor, and it proposed to the method of making small the difference of the amount of heat removal for every area | region. That is, it is preferable to set the total external surface area value of each region so that the heat generated by the gas phase exothermic reaction satisfies the above formula (1) from the viewpoint of preventing the heat inside the reactor from becoming locally high and sufficiently controlling the heat generation. Do.

In Table 1, the total external surface area value of each coil shown by the number of masses in the fluidized-bed reactor 9 shown in FIG. 2 is shown.

0˚ ~ 90˚ 90˚ ~ 180˚ 180˚ ~ 270˚ 270˚ ~ 0˚ min / max Cooling coil 18 20 20 20 0.90 Superheated coil 4 3 4 4 0.75 Steam coil 9 10 8 10 0.80 Sum 31 33 32 34 0.91

First, the total external surface area values of the cooling coils, superheat coils, and steam coils existing in the fan-shaped regions of 0 ° to 90 °, 90 ° to 180 °, 180 ° to 270 °, and 270 ° to 0 °, It is as showing in each column of the said Table 1. As shown in the lowermost column of Table 1, since S _max of the coil shown in FIG. 2 is 34 which is 270 degrees-0 degrees, S _min is 31 which is 0 degrees-90 degrees, and is represented by said Formula (1) The condition is satisfied. In addition, as shown in the rightmost column of Table 1, the condition indicated by the above formula (1) also satisfies the total heat transfer area value for each coil (cooling coil, superheat coil, steam coil). have.

As shown in FIG. 2, by arranging each coil so that the total value of heat transfer area for each type also satisfies the above formula (1), the temperature distribution in the fluidized bed reactor 9 can be uniformly approximated, and the gas phase exothermic reaction in the fluidized bed. It is preferable in performing. In an apparatus in which superheated steam passing through a superheat coil is cooled and supplied to a steam coil, the superheat coil, the desuperheater and the steam coil must be functionally connected in this order, and the arrangement of each coil is usually symmetrical. Can't. Therefore, if there is no idea that the required amount of heat removal is ensured for each fan-shaped region, the total heat transfer area value satisfies the above formula (1), and further, the total heat transfer area value for each type also satisfies the above formula (1). It is not designed to be. On the other hand, arrange | positioning each coil so that the total value of the heat transfer areas for each type may satisfy said Formula (1), respectively is a further preferable form from a heat generation control of a gaseous-phase exothermic reaction.

In this embodiment described above, when operating the fluidized-bed reactor which performs gaseous-phase exothermic reaction, the temperature controllability of a reactor can be improved and water vapor can be used stably and effectively. Therefore, the gas phase exothermic reaction method of the present embodiment is also a temperature control method in the reactor when the gas phase exothermic reaction is performed in the fluidized bed reactor, and generates steam (vapor) using heat generated by the gas phase exothermic reaction. It can also be called a method. In addition, as apparent from the above description, the present embodiment also relates to a heat removal system in a gas phase exothermic system in a fluidized bed reactor, and also relates to a system for producing steam (vapor) using heat generated by a gas phase exothermic reaction. Can be.

As mentioned above, although the best form for implementing this invention was demonstrated, this invention is not limited to the said embodiment. Various modifications are possible in this invention in the range which does not deviate from the summary.

Desuperheat of superheated steam may be a well-known method, and sprays water to the line after confluence of the line 13 or the line 13 and the line 11b, in addition to the method of using the drum (vessel) similar to the said desuperheater 7. The introduction method can also be employ | adopted.

In addition, the above-mentioned steam coil 6 may be abbreviate | omitted. In that case, all the water vapor from the desuperheater 8 is supplied to other equipment.

In the fluidized bed reaction apparatus shown in FIG. 1, steam coils 4, 5, and 6 are provided in the fluidized bed reactor 9, but the superheated steam obtained by flowing in the steam coil 6 is further cooled by desuperheating. After making it possible, it is also possible to supply to the steam coil installed in the reactor 9. In this way, there is no limitation on the number of times of superheated steam desuperheating and the number of times of steam supplied to the heat removing tube provided in the fluidized bed reactor 9.

In addition, there is no limitation on the number of series of each of the steam coils 4, 5, 6, and it is preferable to arrange them uniformly in the reactor.

In addition, arrangement | positioning of each heat removal tube may be shown in FIG. FIG. 3 is a view for explaining the arrangement of the coils in the fluidized bed reactor 9 according to the present embodiment, and the arrangement and the outer surface area are shown in the same manner as in FIG. 2.

0˚ ~ 90˚ 90˚ ~ 180˚ 180˚ ~ 270˚ 270˚ ~ 0˚ min / max Cooling coil 14 20 20 19 0.70 Superheated coil 2 3 4 4 0.50 Steam coil 7 10 8 10 0.70 Sum 23 33 32 33 0.70

First, the total external surface area values of the cooling coils, superheat coils, and steam coils existing in the fan-shaped regions of 0 ° to 90 °, 90 ° to 180 °, 180 ° to 270 °, and 270 ° to 0 °, It is as showing in each column of the said Table 2. As shown in the lowermost column of Table 2, S _max of the coil shown in Fig. 3 is 33, which is 90 ° to 180 ° and 270 ° to 0 °, and S _min is 23, which is 0 ° to 90 °, The condition shown by Formula (1) is satisfied. About the total heat transfer area value of a cooling coil and a steam coil, as shown to the rightmost column of Table 2, the condition shown by said Formula (1) is satisfied.

By arranging each coil as shown in FIG. 3, although it is inferior to the arrangement shown in FIG. 2, the temperature distribution in the fluidized-bed reactor 9 can be made to approximate uniformly, and gas phase exothermic reaction in a fluidized bed is performed. desirable.

[Example]

The invention is further illustrated by examples and comparative examples. However, the present invention is not limited to the following examples. In addition, the fluidized bed reaction apparatus used in the embodiment is similar to that shown in FIG. 1, and the saturated steam is circulated in the heat removal tube (superheat coil) to obtain superheated steam, and the superheated steam is cooled by desuperheating. It was used for normal gas phase exothermic reaction except having the heat removal system which distribute | circulates to another heat removal tube (steam coil). More specifically, the lower part of the fluidized bed reactor had a dispersion tube and / or a dispersion plate of gas as a reaction raw material, and each heat removal tube for removing the heat of reaction was embedded. Moreover, the upper part of the fluidized bed reactor had the cyclone which collects the catalyst mixed in the reaction gas which flows out from a reactor.

The meter and the attached equipment were normally used, and were within a normal error range. The yield and unreacted rate of the reaction product were calculated by the following formula from the analytical data measured by gas chromatography by sampling the reaction gas.

[Yield of reaction product (%)] = [carbon weight in product (g)] / [carbon mass in organic compound (g) supplied as reaction raw material] × 100

[Unreacted rate (%)] = [carbon mass (g) in the organic compound as the unreacted reaction raw material] / [(carbon mass (g) in the organic compound as the supplied reaction raw material)] × 100

Example 1

Propylene, ammonia and air as reaction raw materials were supplied to a fluidized bed reactor 9 as shown in FIG. 2 in a fluidized bed reaction apparatus as shown in FIG. As shown in FIG. 1, the heat removal system includes the cooling coil 2, the superheat coil 3, the steam coils 4, 5, and 6, the gas-liquid separation vessel 1, and the desuperheater 7. 8) was used.

The fluidized bed reactor 9 was a vertical cylinder having an inner diameter of 8 m and a length Lr of 20 m, having an air dispersion plate at a position of 2 m (0.1 Lr) from below and a source gas dispersion tube thereon. In order to measure the temperature of the catalyst bed, the thermometer had 20 points attached between 1.5 and 4.5 m above the air dispersion plate.

The catalyst was filled with a molybdenum-bismuth-iron-based supported catalyst having a particle size of 10 µm to 100 µm and an average particle diameter of 55 µm so as to have a stop layer height of 2.7 m. 56000 Nm ³ / h of air was supplied from the air dispersion plate, and 6600 Nm ³ / h of propylene and 6200 Nm ³ / h of propylene were supplied from the source gas dispersion pipe. The pressure in the reactor was 0.70 kg / cm ² G.

The target value of reaction temperature was set to 443 degreeC, and temperature control was performed using the cooling coil 2 and the superheat coil 3. The average temperature of the 20-point thermometer between the upper 1.5-4.5 m from the air dispersion plate was 445 ° C.

The pressure of the gas-liquid separation vessel 1 was 31 kg / cm ² G, and 65% of the generated high pressure steam was supplied from the line 10 to the steam turbine for driving an air compressor for supplying reaction raw materials. The surplus high pressure steam of 35% was supplied to the steam coil 4 from the line 11, and was also distributed to the desfer heater 7, the steam coil 5, the desuperheater 8, and the steam coil 6.

The amount of steam flowing through the steam coils 4, 5, 6 was controlled by the flow control valve so that the average temperature of the 20 points thermometer between 1.5 and 4.5 m from the air dispersion plate became 440 degreeC. The indicated value of each 20 point thermometer was in the range of 434 degreeC-445 degreeC, and the average value was 440 degreeC. In the desuperheaters 7 and 8, water having a saturation temperature was circulated by a spray circulation method using a pump, and countercurrently contacted with superheated steam taken out from the steam coils 4 and 5, respectively. The operating conditions of the heat removal system were as shown in Table 3. In addition, in the table, "flow rate (%)" represents the mass of the high pressure water vapor which flows out from the gas-liquid separation container 1 as 100%, and is represented by the percentage (it is the same below).

In other facilities, there was a demand for steam of 15 kg / cm ² G, and the steam taken out from the line 14 was sent directly to other facilities and used.

Analysis of the reaction results showed that the yield of acrylonitrile was 81.5% and that of propylene was 1.1%.

Place flux(%) Pressure (kg / cm ² G) Temperature (℃) LINE (10) 65 30 330 LINE (11) 35 30 234 LINE (12) 0 31 235 Steam coil (4) entry / exit 21/21 30/25 234/407 Bypass Steam Coil (4) 14 30 234 Desuperheater (7) Exodus 39 25 227 Steam Coil (5) In / Out 20/20 25/20 227/410 Desuperheater (8) Exodus 43 20 215 Steam Coil (6) In / Out 11/11 20/15 215/403 LINE (14) 43 15 262

[Example 2]

Except having changed the propylene into propane in the reaction raw material, the reaction raw material was supplied to the fluidized bed reactor on the same conditions as Example 1, and the ammoxidation reaction of propane was performed as follows.

The catalyst was filled with a molybdenum-vanadium-based supported catalyst having a particle diameter of 10 µm to 100 µm and an average particle diameter of 55 µm so as to have a height of 2.2 m of the stop layer. Air 64500 Nm ³ / h was supplied from the air dispersion plate, and propane 4300 Nm ³ / h and ammonia 4300 Nm ³ / h were supplied from the source gas dispersion tube. The pressure in the reactor was 0.75 kg / cm ² G.

The target value of reaction temperature was set to 443 degreeC, and temperature control was performed using the cooling coil 2 and the superheat coil 3. The average temperature of the 20-point thermometer between the upper 1.5-4.5 m from the air dispersion plate was 444 degreeC.

The pressure of the gas-liquid separation vessel 1 was 31 kg / cm ² G, and 75% of the generated high pressure steam was supplied from the line 10 to the steam turbine for driving an air compressor for supplying reaction raw materials. The surplus high pressure water vapor of 25% was supplied to the steam coil 4 from the line 11, and was also distributed to the desuperheater 7, the steam coil 5, the desuperheater 8, and the steam coil 6.

The amount of steam flowing through the steam coils 4, 5, 6 was controlled by the flow control valve so that the average temperature of the 20 points thermometer between 1.5 and 4.5 m from the air dispersion plate became 440 degreeC. The indicated value of each 20 point thermometer was in the range of 435 degreeC-444 degreeC, and the average value was 440 degreeC. In the desutter heaters 7 and 8, water of saturation temperature was circulated by the spray circulation system using a pump, and the countercurrent contact was made with the superheated steam taken out from the steam coils 4 and 5, respectively. Operation conditions of the heat removal system were as Table 4 below.

In other facilities, there was a demand for steam of 15 kg / cm ² G, and the steam taken out from the line 14 was sent directly to other facilities and used.

Analysis of the reaction results showed that the yield of acrylonitrile was 52.1% and that of propylene was 10.8%.

Place flux(%) Pressure (kg / cm ² G) Temperature (℃) LINE (10) 75 30 330 LINE (11) 25 30 234 LINE (12) 0 31 235 Steam coil (4) entry / exit 12/12 30/25 234/411 Bypass Steam Coil (4) 13 30 234 Desuperheater (7) Exodus 28 25 227 Steam Coil (5) In / Out 13/13 25/20 227/409 Desuperheater (8) Exodus 32 20 215 Steam Coil (6) In / Out 10/10 20/15 215/403 LINE (14) 32 15 262

[Example 3]

In the same manner as in Example 1 except that the fluidized bed reactor 9 having the arrangement of the heat removal tube as shown in FIG. 3 was used instead of the fluidized bed reactor 9 having the arrangement of the heat removal tube as shown in FIG. Ammoxidation reaction of propylene was performed. The operating conditions of the heat removal system were the same as the conditions shown in Table 3. The indicated value of each 20 point thermometer was in the range of 431 degreeC-448 degreeC, and the average value was 440 degreeC.

Analysis of the reaction results showed that the yield of acrylonitrile was 81.0% and that of propylene was 1.1%.

Comparative Example 1

Ammonia oxidation reaction of propylene was performed like Example 1 except having not used the heat removal system shown in FIG. 1, and using the heat removal system as shown in FIG. The heat removal system shown in FIG. 4 is provided with the gas-liquid separation container 1, the cooling coil 2, and the superheat coil 3 similarly to the said Example, and the steam coil 4, 5, 6 ) And desuperheaters 7 and 8 were not provided. Arrangement of each coil in this heat removal system was as showing in FIG. 5, and the sum total of the external surface area in each fan-shaped area | region of each coil was as showing in Table 5. As shown in FIG. In addition, FIG. 5 shows arrangement | positioning and outer surface ratio of each coil similarly to FIGS.

0˚ ~ 90˚ 90˚ ~ 180˚ 180˚ ~ 270˚ 270˚ ~ 0˚ min / max Cooling coil 13 20 20 20 0.65 Superheated coil 3 3 4 4 0.75 Sum 16 23 24 24 0.67

The target value of reaction temperature was set to 440 degreeC, and temperature control was performed using the cooling coil 2 and the superheat coil 3. The indicated value of each 20 point thermometer between 1.5-4.5 m upwards from the air dispersion plate was in the range of 426 degreeC-451 degreeC. In addition, the average value of the indicated values of these 20 points of thermometers was 440 degreeC.

The excess high pressure steam taken out from the line 11 was sent to the other equipment which used this steam after dropping the pressure from 30 kg / cm <^2> G to 15 kg / cm <^2> G by the pressure regulating valve installed in the line 11.

As a result of analyzing the reaction results, the yield of acrylonitrile was 79.9%, and the unreaction rate of propylene was 1.0%.

Comparative Example 2

The ammoxidation reaction of propane was performed in the same manner as in Example 2 except that the heat removal system shown in FIG. 1 was not used and the heat removal system shown in FIG. 6 was used. The heat removal system shown in FIG. 6 is provided with the gas-liquid separation container 1, the cooling coil 2, the superheat coil 3, and the steam coils 4, 5, 6 similarly to the said Example. On the other hand, the desuperheaters 7 and 8 were not provided. Arrangement of each coil in this heat removal system was as showing in FIG. 2, and the total external surface area value in each fan type area | region of each coil was as showing in Table 1. As shown in FIG.

The target value of reaction temperature was set to 443 degreeC, and temperature control was performed using the cooling coil 2 and the superheat coil 3. The average value of the indicated value of the 20-point thermometer between 1.5-4.5 m upwards from the air dispersion plate was 444 degreeC.

The pressure of the gas-liquid separation vessel 1 was 31 kg / cm ² G, and 75% of the generated high pressure steam was supplied from the line 10 to the steam turbine for driving an air compressor for supplying reaction raw materials. Excess 25% of the high pressure water vapor was introduced from line 11 and the deficiency introduced further steam from line 12 and flowed into steam coils 4, 5 and 6.

The amount of steam flowing through the steam coils 4, 5, 6 was controlled by the flow control valve so that the average temperature of the 20 points thermometer between 1.5 and 4.5 m from the air dispersion plate became 440 degreeC. The indicated value of each 20 point thermometer was in the range of 435 degreeC-444 degreeC, and the average value was 440 degreeC. The operating conditions of the heat removal system were as shown in Table 6.

In other facilities, there was a demand for steam, and water vapor taken out from line 14 was sent, but it was released to the atmosphere because it was 5% surplus and there was no use.

As a result of analyzing the reaction results, the yield of acrylonitrile was 52.1% and that of propane was 10.8%.

Place flux(%) Pressure (kg / cm ² G) Temperature (℃) LINE (10) 75 30 330 LINE (11) 25 30 234 LINE (12) 12 31 235 Steam coil (4) entry / exit 12/12 30/25 234/411 Steam Coil (5) In / Out 14/14 30/25 234/409 Steam Coil (6) In / Out 11/11 30/25 234/409 LINE (14) 37
5% surplus included 25 410

The method of the present invention can be effectively used when performing a gas phase exothermic reaction using a fluidized bed reactor.

1 is a schematic view showing an example of a fluidized bed reaction device of the present embodiment.

FIG. 2 is a conceptual diagram showing the arrangement in the direction orthogonal to the S direction of each heat removal tube according to the present embodiment, using a mass together with the outer surface area of each heat removal tube. FIG.

FIG. 3 is a conceptual diagram showing an arrangement in a direction orthogonal to the S direction of each heat removing tube according to another embodiment of the present invention, using a mass together with the outer surface area of each heat removing tube. FIG.

4 is a schematic view showing a fluidized bed reaction apparatus according to a comparative example.

5 is a cross-sectional view for explaining the arrangement of each heat removal tube in a fluidized bed reactor according to a comparative example.

6 is a cross-sectional view for explaining the arrangement of each heat removal tube in a fluidized bed reactor according to another comparative example.

<Code description>

1: gas-liquid separation vessel, 2: cooling coil, 3: superheat coil, 4: steam coil, 5: steam coil, 6: steam coil, 7: desuperheater, 8: desuperheater, 9: fluidized bed reactor, 10 14: line

Claims (8)

As a method of supplying a reaction raw material to a fluidized bed reactor including a plurality of heat removal tubes therein, and performing gas phase exothermic reaction, (a) inside the one heat exchanger tube, a liquid of a first steam and / or a material constituting the first steam is circulated to defrost the fluidized bed reactor and superheated steam from the first steam and / or the liquid Creating a process, (b) contacting the superheated steam with a liquid of a material constituting the first steam with a desuperheater to lower the temperature and / or pressure of the superheated steam to generate a second steam; (c) A gas phase exothermic reaction method comprising the step of circulating the second steam inside the other heat generating tube. The gas phase exothermic reaction method according to claim 1, wherein the reaction raw material includes alkanes and / or alkenes having 2 to 4 carbon atoms. The gas phase exothermic reaction method of claim 2, wherein the alkanes are propane and / or isobutane. The process of claim 2, wherein said alkenes are propylene and / or isobutylene. The gas phase exothermic method according to any one of claims 1 to 4, wherein the gas phase exothermic reaction is an ammoxidation reaction. A fluidized bed reaction apparatus for a gas phase exothermic reaction comprising a fluidized bed reactor, a plurality of heat removal tubes disposed therein, and a desuperheater connected to one of the heat removal tubes and the other heat removal tubes, (a) said one heat removal tube heats said fluidized bed reactor by distributing a first vapor and / or a liquid of a substance constituting said first vapor therein, and superheats said first vapor and / or said liquid To produce steam, (b) the desuperheater is to contact the superheated steam with a liquid of a substance constituting the first steam to lower the temperature and / or pressure of the superheated steam to generate a second steam; (c) The other heat removing tube is configured to distribute the second steam therein. The fluidized bed reaction apparatus according to claim 6, wherein a plurality of the heat removing tubes are arranged to satisfy a condition represented by the following formula (1). 0.70 S _max ≤S _min (One) [Equation (1), S _max is the four fluidized zone reactors through the center of the cross section substantially orthogonal to the flow direction of the reaction raw materials and the reaction product therein and in four regions in an imaginary plane orthogonal to the cross section. Up represents the largest outer surface area total value of the outer surface area total value of the first yeolgwan in each of the areas, S _min is the smallest outer surface area of the outer surface area total value of the first yeolgwan in each of the regions in the case of Represents the total value.] The outer surface area of the said other heat removal tube is 1-10 times, respectively, based on the said outer surface area of the said heat removal tube which has the minimum outer surface area among a plurality of said heat removal tubes. , Fluidized bed reaction apparatus.

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