JPS5853932B2 - Uniform heating reactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating type, catalyst internal type, fixed bed type reactor.

A tubular reactor is generally used as a fixed bed reactor for industrially carrying out gas-solid catalytic reactions at high temperatures.

As for the external heating method of this multi-tube heat exchanger type, when the temperature exceeds several hundred degrees, direct heating method or indirect method using heat medium such as dowsam or hot air can be considered, but electric heating method (especially induction heating ) is advantageous in terms of controllability, automation, and environmental protection.

However, even with this method, in the case of medium to large scales, uneven heat input in the radial direction cannot be avoided due to the electrothermal characteristics, and as a result, uneven reaction occurs within the tube and complete reaction may not be achieved. There is.

To avoid this, a plurality of small-scale devices must be manufactured in parallel, which is extremely disadvantageous in terms of layout and economy.

The present invention solves the non-uniformity of the temperature distribution in the radial direction of the commonly used former mold in a device that performs gas-solid catalytic reactions using a fixed bed vertical reactor at high temperatures of several 100 degrees or higher. The purpose is to solve this problem particularly in the case of medium to large scale capacity and to provide an economical device.

Conventional tubular reactors generally include a catalyst internal type in which a catalyst is filled in a tube (one or more tubes) and an external type, and in both cases a reaction is caused by flowing gas into the catalyst-filled layer.

Here we will consider infix expressions.

A single tube may be used when the diameter is less than several 1007n7IL, but a multi-tube type is often used when the diameter is larger or when it is desired to make the temperature distribution uniform in the radial direction.

Furthermore, it is difficult to maintain the inside of each tube at the same high temperature by supplying heat from the outside in the case of electric heating systems, because due to the electric heating characteristics, the heat input to the center in the radial direction is usually lower than that to the outer periphery. .

The degree of decrease in heat input depends on the device shape and the physical properties of the internal photonic debris, but it is at least 5 to 10 times larger, or several tens of times in large-scale devices.
It is estimated that it will be 0%.

To avoid this, it is necessary to arrange a plurality of small-scale devices in parallel, which is disadvantageous both in terms of space and economy.

In one study case, even a device with a nominal filling volume of 0.25-meter (external diameter φ700 mrtt x 3,000 mrrt-tube φ25.4/19.6 350 tubes) had to be designed in parallel with 3 units of 120 tubes/unit. Moreover, the cost is about twice that of the method of the present invention.

In the present invention, the shape of the filled layer is not tubular but annular with a double cylinder, and in order to further improve the heat transfer effect and to make the gas flow uniform, an interval of several iomm is provided in the vertical direction inside the double cylinder. The feature is that a partition plate is installed at the center.

By setting the size of the annular part (the gap between the outer cylinder and the inner cylinder) in the double cylinder from several romrrt to 100 mm or less, the heat input from the outer peripheral part can uniformly reach the inner cylinder wall,
Coupled with the fact that the partition plate also generates heat during induction heating and the fin effect of the partition plate, the temperature distribution within the catalyst-filled layer becomes constant.

When the present invention is applied to the above-mentioned study case, the outer cylinder diameter is 650 mm.
, an inner cylinder diameter of 540 mm and a length of 3,000 mm, making it an economical device.

FIGS. 1a and 1b show a partial longitudinal sectional view and a cross sectional view, respectively, of a general multi-tubular reactor.

Figures 2a, b show similar cross-sections of a double cylinder reactor according to the invention.

In these figures, catalyst receivers, expansion joints, main bodies, heaters, etc. that are not directly related to the present invention are not particularly shown, or are omitted to the extent that they are simply shown.

Figure 1 shows the reaction tubes 3 attached to the upper and lower tube plates 2A and H.
The inside of the reactor is filled with a catalyst, and a reaction is carried out at a predetermined reaction temperature while gas passes through the reactor from above to below.

In order to maintain the reaction temperature, heat is supplied from a heating source 4 (electric heater, induction heating type, etc.) on the outer periphery.

In this case, a difference occurs in the internal temperature of the reaction tube between the outer circumference and the center.

Figure 2 shows a device in which the annular part 17 between the inner and outer cylinders 13 and 14 attached to the upper and lower flanges 12A and 12B is filled with a catalyst, and the gas is used to carry out the reaction in the same manner as in Figure 1. be.

The partition plate 15 extends longitudinally and radially from the outer cylinder 1 at equal intervals around the periphery.
4 Some are welded to the inside.

The heat necessary for the reaction is supplied from the outer periphery through the outer cylinder and the partition plate by a heating source 16 such as an electric heater or an induction heating type.

As described above, in the present invention, due to the annular shape of the reaction layer and the longitudinal and radial partition plates 15 to the reaction layer, heating of the reaction layer is more uniform than in the conventional method.

[Brief explanation of drawings]

Figure 1 is a partial vertical sectional view of a general multi-tubular reactor and
b: A cross-sectional view; FIG. 2 shows the double cylindrical reactor with partition plates of the present invention in the same way as FIG. 1. IA, IB・・・Top, lower main body channel, 2A
. 2B... Upper and lower tube sheets, 3... Reaction tube, 4... Heat source (in conventional type), 11
A, 11B...Top, lower body channel, 1
2A, 12B...Top, bottom flange, 13...
...Inner cylinder, 14...Outer cylinder, 15...
- Partition plate, 16... Heat source (in the present invention)
.

Claims (1)

[Claims] 1. A reactor in which the annular part between the inner and outer cylinders is used as a reaction layer, and several partition plates are placed there to partition the cylinders in the longitudinal and radial directions, and a heating source is placed on the outer periphery of the outer cylinder.