JPS5982943A - Multitube type exothermic reaction device - Google Patents

Abstract

PURPOSE:To reduce initial and running costs by incorporating a cooler tube bundle in a reactor so that a titled device is made compact and a large temp. difference between the inside and outside of a reaction tube is taken. CONSTITUTION:A cooler tube bundle 12 for a heat medium is provided in the central part in a reactor 11 of a multitube type exothermic reaction device which removes the reaction heat in reaction tubes 13 by the circulation of the heat medium. The tube bundles 13 are disposed around said tube bundle and a baffle plate group which has the plane rectangular to the tube bundles and is disposed alternately with large diameter hollow discs 15, small diameter hollow discs 16 and middle diameter solid discs 17 provided on the same plane. As a result, the heat medium in the reactor 11 is partly cooled many times in the midway of circulation and has about the same temp. as the temp. in the stage of departing by mixing with the heat medium having an increased temp. as it passes through the clearances. If the number of the passage is increased, the higher difference between the inside and outside temp. in the reaction tube is taken. The device is thus made compact and the initial and running costs are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses phthalic anhydride (PA), acrylic acid (AA)
The present invention relates to a multi-tubular exothermic reactor lζ which can be applied to a methyl methacrylate-h (MMA) reactor, etc.

FIG. 1 shows an example of a conventional device for carrying out a chemical reaction using a multi-tubular reactor, removing the reaction heat generated during the reaction using a heat medium, and controlling the reaction temperature. 46 in FIG. 1, a tube bundle (2) provided in the reactor (1) and filled with catalyst.
), when the process fluid (3) is passed through and reacted, heat of reaction is generated. This reaction heat is transferred to the circulation pump (6)
A part of the heat medium is extracted and passed through the cooler (4) by the extraction pump (5), and then absorbed by the heat medium flowing inside the reactor (1) barrel. 1
), the heat of reaction is removed.

In addition, the reaction temperature is controlled by changing the flow rate of the heat medium that has passed through the cooler (4) and returned to the reactor (1) using a control valve (force). is recovered by generating steam (8) or the like.

However, in this conventional method, the equipment is complicated, and the control valves and piping provided for controlling the flow rate of the heat medium act as resistance, so that the extraction pump (5) requires extra power.

In addition, since cooling of the heat medium is performed outside the reactor, the heat absorption capacity of the heat medium is reduced near the reactor (1) outlet, so the inside and outside of the fake reaction tube is as much as that near the reactor (1) inlet. Y11
Since it was not possible to set the λ degree difference, there was no choice but to keep the temperature difference to a low level or increase the flow rate of the heat medium, and the reactor (1) had to be made larger. Furthermore, it was difficult to deal with cases where there was a difference in exothermic reaction in the longitudinal direction of the reaction tube.

The present invention was proposed in order to solve the above-mentioned conventional drawbacks, and aims to provide a compact device instead of the conventional complicated device.The present invention is a multi-tube device that removes the reaction heat in the reaction tube by circulating a heat medium. For both the male and female type heat generating reactor, a large diameter hollow disk, a small diameter hollow disk, and a medium diameter solid disk are arranged alternately, which are perpendicular to the tube bundle and installed in the same horizontal plane. The present invention relates to a multi-tubular exothermic reaction device characterized by the presence of Kokichi.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows one embodiment of the present invention. In the figure, inside the reactor 0υ, a cooling tube bundle a21 is provided in the center, and a reaction tube bundle 03) is provided in parallel to this on the outer periphery, and one or both of its upper and lower ends are fixed to a common tube plate (I4). do.

'Also, on the body side of the reactor (I]), there are a large diameter hollow disc 05), a small diameter hollow disc αG), and a medium diameter solid disc 05), which are circular in the same plane.
7) Provide a group of baffle plates arranged alternately. The relative dimensions of these disc baffle plates are as follows: outer diameter of medium-diameter solid disc 07)>inner diameter of large-diameter hollow disc 051>small-diameter hollow disc (1,
6) in relation to the outer diameter (Fig. 8). Further, a circulation pump 124) for circulating the heat medium is provided outside the reactor together with the necessary piping system.

Next, to explain the operation, the process fluid (18) flows down in the reaction tube bundle (13) from above the reactor (11) or rises in the reaction tube bundle (I3) from below the reactor 01) to carry out the reaction. reaction, generating heat of reaction. This reaction heat is absorbed by the heat medium sent to the shell side of the reactor (11) by the circulation pump 04).

At this time, the heat medium flows through the opening G9 of the annular lower liquid distribution box (19) provided on the outer periphery of the lower part of the reactor (jl).
11) flows centrally at right angles to the tube bundle.

A part of it flows upward through II (20) between the inner periphery of the large-diameter hollow disk (15) and the outer periphery of the small-diameter hollow disk (1G), and is blocked by the medium-diameter solid disk 07). The tube changes direction and flows in the circumferential direction at right angles to the tube bundle.

The waste flows upward through the hollow part (2I) of the small-diameter hollow disc 06, is blocked by the medium-diameter solid disc (17) above it, changes direction, and flows through the cooling tube bundle (12). The fluid inside the cooling pipe flows at right angles to the outer circumferential direction and is cooled by the gap +
2o) is mixed with the heat medium that has passed through the reactor (1]).
When flowing into the pipe, the pipe becomes at a low temperature and flows upward at the outer periphery, is blocked by the large-diameter hollow disk (15), changes direction, and flows toward the center at right angles to the tube bundle. In addition, D in Fig. 4 is the outer diameter of the medium-diameter solid disk (17), D2 is the same diameter of the large-diameter hollow disk (15), and D3 is the outer diameter of the small-diameter hollow disk (16). .

Thereafter, the same flow as above is repeated to open the annular upper collection box 23) provided at the outer circumference of the upper part of the reactor U
3 (L) and flows out from the circulation pump (
21) and circulates to the lower liquid distribution box 09). In addition,
The same applies when the heat medium circulates from the upper distribution box to the lower collection box in the same process as above.

As explained in detail above, in the present invention, the condenser tube bundle is incorporated into the reactor, so the entire device can be made compact and equipment costs can be reduced. In addition, since the pump for the heat medium system can be one circulation pump, by distributing the flow rate of the heat medium to the cooler with the baffle plate, the head of the circulation pump can be reduced, and the operating power can also be reduced.

By the way, a part of the heat medium is cooled many times during the circulation, and it mixes with the heated heat medium that passes through the gap and reaches the same temperature as when it started, so increasing the number of times will increase the temperature. Cheng,
It is possible to create a large temperature difference between the inside and outside of the reaction tube.

Therefore, if the amount of heat medium is the same and the temperature at the heat medium inlet is the same, a large temperature difference can be achieved, and the heat transfer area of the reaction tube can be made small. In addition, since a smaller amount of heat medium is required to be circulated to remove the same amount of reaction heat, this is within the power range of a circulation pump. Note that if the same amount of heat medium is used, the inlet temperature of the heat medium can be brought close to the reaction tube temperature, so it is possible to cope with reactions that require strict temperature control.

A part of the heat transfer medium bypasses the gap, so
Compared to the conventional method, which suffers pressure loss from the full volume baffle plate, the pressure loss is smaller, which increases the power range of the circulation pump. Furthermore, even if there is a difference in the exothermic reaction in the longitudinal direction of the reaction tube, arbitrary heat removal is possible by appropriately setting the gap size between each hollow disk.

[Brief explanation of the drawing]

Fig. 1 shows an example of a conventional multi-tubular reactor, but Fig. 2 shows an analysis of the reactor according to an embodiment of the present invention, and Fig. 8 shows an analysis of the reactor according to an embodiment of the present invention. FIG. 4 is an enlarged view showing the relative dimensions of the disc baffle plate in FIG. Explanation of main parts of the diagram 11...Reactor 12...Cooling tube bundle ■3...
・Reaction tube bundle 14...Tube sheet 15...Large diameter hollow disk 16...Small diameter hollow disk 17...Mountain diameter solid disk Patent Applicant: Mitsubishi Heavy Industries, Ltd.

Claims (1)

[Claims] In a multi-tubular exothermic reaction device that removes the reaction heat in the reaction tube by circulating a heat medium, a heat medium cooler tube bundle is installed in the medium heat section of the reactor, and a reaction tube bundle is installed in parallel around it. , a group of baffle plates in which large-diameter hollow disks, small-diameter hollow disks, and medium-diameter solid disks are alternately arranged, which are provided in the same horizontal plane and are perpendicular to the pipe bundle. Multi-tubular exothermic reactor.