SU381384A1 - METHOD OF REGULATING THE TEMPERATURE REGIME OF EXOTHERMIC PROCESSES - Google Patents

Description

The invention relates to a method for adjusting the temperature regime of exothermic processes in a fixed bed of a solid catalyst. When exothermic processes are carried out in a fission catalyst layer, a dynamic equilibrium heat release — heat sink — is established, which leads to the appearance of a temperature gradient along and perpendicular to the catalyst gradient layer, limiting the intensity of the process. With an increase in the intensity of the process, the temperature at the most HarpeToii point of the layer, as well as the “hot point” mentioned, can become higher than the maximum possible temperature; subject to terms of reference and process.

Use a method of controlling the temperature regime of exothermic processes in a non-single-bed catalyst bed by reacting reagents into the catalyst bed. The known method is characterized by constant supply of reagents in one direction. For most catalysts, this leads to noosteine transfer along the layer and even partial entrainment of volatile assets) of the catalyst components (zinc acetate, mercuric chloride, copper chloride, etc.). In addition, the implementation of an intrinsic method is associated with the cost-consuming and costly design and control system of the gearbox.

To increase catalyst life

It is proposed to change the direction of supply of the reactants to the catalyst bed in 10-100 minutes.

FIG. 1 shows schematically a reactor with iodine motion ;; the 1st catalyst bed (adiabatic, tubular, pipe-and-ary, etc.); ia 2 — temperature profiles for the nepnoio reaction order; FIG. 3 - dependence of the temperature difference between the points on the time between the switches.

Submission of Reeites to the reactor / in one direction takes place within a certain time interval. During this time, due to the difference in reaction rates in the catalyst layer, a uniform temperature tolerance over the layer occurs. For most of the processes, the hot spot is located in the first third of the layer due to the large co-concentration of the initial reagents in the drink (slg, fig, 2, curve 4). After a given time interval has elapsed, using the switching devices 2, the direction of the current passing through the reactor is reversed. As a result, the switch and the temperature distribution along the catalyst bed changes - at a "hot point, the temperature is lit, and in the" cold zone it rises, forming a new "hot point. After a predetermined period of time, the direction of the reactants is reversed, and so on.

3

When the reactor is operated in the proposed thermostat with the periodic change in the direction of gas flow, the temperature gradient across the layer decreases, which allows an increase in the flow of reactants into the reactor without disturbing the dynamic equilibrium and heat generation - a sink. The periodic change in the direction of cnacoSciiByeT to a more uniform distribution of the volatile active components of the catalyst, and therefore, provides a more uniform working out of the catalyst, increasing the oroK of its service.

FIG. Figure 2 shows the profile when operating without switching (curve A) and the nature of the profile change in time and after changing the direction (the curves show the time in seconds since the change of direction). The curves are calculated on the digital computer in relation to the parameters of the industrial reactor for the synthesis of vinyl acetate from acetylene and acetic acid. On fng. 3 but azan depends on the temperature between the points, with a relative length of 0.3 and 0.7 from the time between switching (curve B is the head of the maximum temperature difference, and curve C is the maximum difference for the cycle temperature difference ).

four

For example, when switching directions

after 1200 s, the maximum temperature difference is 8 °, and averaged over a cycle of 4 °.

When operating without switching, the difference is 11 °.

Thus, when the reactor is operated in the proposed 1-stationary, mode, the non-uniform temperature across the layer significantly decreases, and the higher the switching frequency, the greater the temperature uniformity.

The amount of time between switching; within a range of 10-100 minutes is refined by conducting an eco-experiment: in changing the direction of the reaction mixture or by simulating this change on a computer.

Subject invention

The method of adjusting the temperature regime of exothermic processes in a fixed catalyst bed by feeding reagents into a catcher bed, characterized in that, in order to increase the service life of the catalyst, the reagent feed direction is changed into the catalyst bed after 10-100 minutes.

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