JPH0658610B2 - Temperature control method for distribution device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a temperature control method for a flow apparatus involving an exothermic reaction or an endothermic reaction.

<Prior Art> In various chemical plants, there are cases where a flow-through catalyst layer involving an endothermic reaction or an exothermic reaction, a flow-through device comprising a reaction furnace, etc. is used, but there is a problem that the temperature control is difficult. It was For example, as shown in FIG. 1, a catalyst layer 2 formed by filling a catalyst in a catalytic reactor 1 is provided,
Generally, an electric heating type heating means 4 and 5 are arranged so as to surround the catalytic reactor 1.
12 to 12, since the directions of heat transfer are various and the mutual interference strongly acts between the temperatures at each point, the heat transfer is accurately predicted and the temperature of the catalyst layer 2 is controlled. Is extremely difficult.

Further, for example, when the reaction in the catalyst layer 2 is an exothermic reaction, the exothermic reaction in the catalyst layer depends on the temperature as shown in FIG. There is a significant difference in the temperature distribution of the catalyst, and it is extremely difficult to control this automatically.In particular, the heating temperature becomes excessive due to the delay of heat transfer between the heating means and the catalyst layer. In that case, the temperature of the catalyst layer may run away, causing troubles such as damage to the catalyst. Therefore, a skilled operator is required for the operation of such a catalytic reactor, and the operation is extremely complicated.

<Problems to be Solved by the Invention> In view of the above-mentioned drawbacks of the conventional technology, a main object of the present invention is to provide a distribution apparatus capable of accurately and automatically controlling the temperature of the distribution apparatus, which has been difficult to automate. Temperature control method.

<Means for Solving the Problems> According to the present invention, such an object is to provide a plurality of heating means arranged along the flow direction of the fluid in the circulation device for circulating the fluid, A heater temperature detecting means attached to each of the plurality of heating means, a fluid temperature detecting means arranged at a position corresponding to each of the plurality of heating means in the circulation device, and the heater temperature detecting means. The driving means for driving the heating means so as to match the detected value of the first target temperature with the first target temperature, and the first target temperature so as to match the detected value of the fluid temperature detection means with the second target temperature. A temperature control method for a flow device comprising a target temperature setting means for controlling, wherein the second target temperature is set as a temperature raising target temperature lower by a predetermined value than the final target temperature, and the fluid temperature The value detected by the detection means is the temperature A rapid temperature rising process of simultaneously driving the plurality of heating means after the first target temperature is set to a level that reaches the level, and the second target temperature is transiently higher than the temperature rising target temperature by a predetermined value. The target temperature is set, and the first target temperature is updated to a level at which the detection value of the fluid temperature detecting means reaches the temperature, and then the plurality of heating means are sequentially driven individually, and the fluid temperature detecting means is provided. And a fine adjustment process of gradually increasing the transient target temperature until the detected value of 1 reaches the final target temperature.

<Operation> As described above, the flow device is divided into a plurality of sections along the flow direction of the fluid, and the individual sections are cascade-controlled to enable accurate temperature control. By dividing into the fine adjustment process, quick start-up and precise control are possible.Furthermore, during steady operation, by continuing the fine adjustment mode, precise control is continued even if there is a disturbance. It becomes possible to do it.

<Embodiment> Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 diagrammatically shows the construction of a temperature control device for a catalyst layer as a flow device according to the invention. The catalytic reactor 1 is provided with a catalyst layer 2 in which a catalyst is filled in a pipe line 7 over a certain length, and a reactant made of a fluid flows in a direction of an arrow 20 shown in the drawing. . Four heating means 3 to 6 composed of, for example, electric heating elements are arranged along the length of the catalytic reactor 1.

Each heating means 3-6 is provided with a temperature sensor 9a-9d for controlling these heating means, respectively.
The temperature sensors 9a to 9d provided in the heating means 3 to 6 are
Four temperature controllers 10a to 1 including PID controllers
0d is supplied with the actual temperature signals of the heating means 3 to 6, respectively, and these temperature controllers heat the corresponding heating means 3 to 6 through the driving devices 11a to 11d by feedback control.

On the other hand, inside the catalyst layer 2, four temperature sensors 8a to 8d are provided along the length direction at positions corresponding to the heating means 3 to 6, respectively.
Is provided. These temperature sensors 8a to 8d may be appropriately selected from a large number of thermocouples installed in the catalytic reactor 1 along the longitudinal direction. The actual temperature signals of the fluid obtained by the temperature sensors 8a to 8d are supplied to the controller 12 having a built-in microprocessor,
This controller 12 is the temperature controller 10a-
The set temperature of 10d is controlled respectively.

The operating principle of the device according to the invention will now be described with particular reference to FIG.

First, when the catalytic reactor is started up, if the final target temperature of the catalytic reactor is, for example, 400 ° C., the temperature inside the catalyst layer 2 is set to a level that is 10 ° C. lower than 390 ° C. Temperature target temperature to the temperature controller 1
Output from 0a to 10d, and known cascade control is simultaneously performed for all the heating means 3 to 6. When the temperature of each point in the catalyst layer 2 reaches 390 ° C., the target temperature of the entire catalyst layer is 8 ° C. lower than the final target temperature, that is, the transitional target temperature 2 ° C. higher than the temperature raising target temperature. In addition, the set target temperatures of the temperature controllers 10a to 10d are sequentially changed from the upstream side to the downstream side according to the flow direction of the fluid. This is achieved by controlling the target temperature of each of the temperature controllers 10a-10d using the microprocessor built in the controller 12.

That is, the temperature of the entire catalyst layer is 390
When the temperature exceeds 8 ° C., that is, from point A, the temperature sensor 8a in the catalyst layer 2 in the same zone indicates 392 ° C. by updating and controlling only the set temperature of the temperature controller 10a on the most upstream side.
The heating means 3 is controlled until the temperature exceeds the point, and the point B is reached. Then, by controlling the heating means 4 in the zone on the one downstream side, the point C is reached to the point D so that the temperature detected by the temperature sensor 8b reaches 392 ° C. In this way, as indicated by points E, F, G, and H, similar control is performed for each heating means corresponding to each zone, and the fourth, that is, the most downstream heating means 6 is controlled. At the time of completion, the target temperature value in the catalyst layer 2 is further raised by 4 ° C. to 396 ° C., and similar control is sequentially performed for each heating means 3-6.

Now, the temperature in the catalyst layer 2 is measured at four points in each zone,
When only one of the three points is controlled to the target temperature, the other three points will also be affected and fluctuate.
It is difficult to perform stable control because the respective parts of the above interfere with each other in a complicated manner. Therefore, according to the present invention, the four heating means are sequentially and individually controlled along the flow direction of the fluid, and the entire catalyst layer is controlled to be in an equilibrium state little by little for each individual portion.
This is intended to stabilize the overall control operation. In the case of the present embodiment, the controller 12 has a built-in microprocessor and has both a controller for controlling the target temperature of each of the temperature controllers 10a to 10d and a program controller for sequentially controlling the heating means. Has become.

By repeating this procedure, finally, all the temperature sensors 8a to 8d in the catalyst layer 2 have a final target temperature of 400 ° C ± 1 ° C.
Be within the range of. When the entire area of the catalyst layer 2 reaches the final target temperature in this way, steady operation is performed while continuing this fine adjustment mode. In this way, it becomes possible to continue to appropriately control the catalytic reactor against various disturbances such as catalyst activity deterioration.

<Effects of the Invention> As described above, according to the present invention, by operating the controller 12 according to a predetermined program, the temperature control of a flow device such as a catalytic reactor, which has been difficult in the past, can be stably, accurately and automatically performed. This can be performed, and a great effect can be achieved in terms of productivity improvement and labor saving.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing directions of temperature transmission in a catalytic reactor device to which the present invention can be applied. FIG. 2 is a graph showing the temperature distribution inside the catalytic reactor and the heating means with and without the reaction by the catalyst. FIG. 3 is a schematic block diagram showing an outline of a temperature control device for a catalyst layer according to the present invention. FIG. 4 is a block diagram showing the functional structure of the embodiment shown in FIG. FIG. 5 is a three-dimensional graph showing the process of temperature control according to the embodiment shown in FIGS. 3 and 4. DESCRIPTION OF SYMBOLS 1 ... Catalyst reactor, 2 ... Catalyst layer 3-6 ... Heating means, 7 ... Pipe lines 8a-8d, 9a-9d ... Temperature sensor 10a-10d ... Temperature controller 11a-11d ... Driving device 12 ... Controller, 20 ... Arrow

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 59-98221 (JP, A) JP 61-9275 (JP, A) JP 61-156316 (JP, A) Actual development 55- 3862 (JP, U) Japanese Patent Sho 49-29403 (JP, B1)

Claims (1)

[Claims] 1. A plurality of heating means arranged along a flow direction of a fluid in a circulation device for circulating a fluid, heater temperature detecting means attached to each of the plurality of heating means, and The fluid temperature detecting means arranged at a position corresponding to each of the plurality of heating means in the circulation device, and the heating means so that the detection value of the heater temperature detecting means coincides with the first target temperature. A temperature for the flow device, which includes a driving means for driving and a target temperature setting means for controlling the first target temperature so that the detection value of the fluid temperature detecting means matches the second target temperature. A control method, wherein the second target temperature is set as a temperature raising target temperature lower by a predetermined value than the final target temperature, and the first target is set to a level at which the detection value of the fluid temperature detecting means reaches the temperature. After setting the temperature, A rapid temperature raising process in which a plurality of heating means are driven simultaneously, the second target temperature is set as a transient target temperature higher than the temperature raising target temperature by a predetermined value, and the detection value of the fluid temperature detecting means is The first target temperature is updated to a level at which the temperature is reached, and then the plurality of heating means are sequentially driven individually, and the transient target temperature is reached until the detection value of the fluid temperature detection means reaches the final target temperature. And a fine adjustment process for gradually increasing the temperature.