SU1412802A1 - Method of controlling the process of activation of chrome-nickel-phosphate catalyst for dehydration of hydrocarbons - Google Patents

Abstract

The invention relates to catalytic chemistry, in particular, a method for controlling the activation process of a calcium-calcium phosphate catalyst for the dehydrogenation of hydrocarbons. The goal is to reduce the activation time and the activity of the catalyst. The process is carried out by controlling the consumption of the vapor-air mixture at the stage of burning graphite due to the pressure change of this mixture: and over the catalyst layer depending on the concentration of CO j in the exhaust gases at 450-590 ° C. Then, with a uniform increase in temperature from 540 to 600 ° C At a rate of -6 ° C / h, a catalyst is being developed for the removal of sulfur compounds. hygroscopic moisture and ordering the microstructure of the catalyst. The method makes it possible to reduce the catalyst activation time at the development stage from 60 hours to IO hours and to increase productivity over the mileage of the catalyst by 4.2% with the same consumption of raw materials. 1 silt, 1 tab. i (L

Description

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The invention relates to the activation of catalyzers for the dehydrogenation of hydrocarbons, in particular, to methods of controlling the activation process. The purpose of the invention is to reduce the time of activation and increase the quality of the preparation of the catalyst due to certain conditions for burning graphite and developing the catalyst.

I The drawing shows the activation process control scheme. I The process of catalyst activation, I involving the steps of burning the graph and catalyst development I, is carried out in reactors I and 2 with a fixed catalyst bed, in which, after activation, the hydrocarbons are dehydrogenated,

I Raw materials and steam are fed to the reactors after I preheating in the furnace 3. i. The process control system includes a logical mask A to switch the operating modes of the reactors, the steam flow controller 5 to the furnace, the regulator; torus 6 of raw material consumption to the furnace, regulator 7 of air consumption to the reactors, regulating; torus 8 temperatures in reactors, pressure sensors 9 per cent of catalyst beds of reactors 1 and 2, CO2 content analyzer 10 in exhaust gases, pressure regulator 11 in reactors, temperature programmer 12, pressure correction unit 13, and timer 14.

An example of the implementation of the process (for the process of dehydrogenating isoamylene to isoprene).

Reactors 1 and 2 fill the IM-2204 chromium-calcium-phosphate catalyst with 12 tons in each reactor. The catalyst contains calcium, nickel and chromium cations associated with phosphoric acid radicals, A.%: Ca 28; five; 2

When pelletizing, graphite is added to the catalyst for strength. After loading into the reactor, the catalyst is subjected to activation, which includes two stages: the burning of graphite and the development of a catalyst. .

Stage graphite burning. The stage involves heating the catalyst to 450 ° С (duration h), actually burning out (duration / 40 h) and heat treatment with superheated steam (duration / v 20 h). The burning is carried out at a steam consumption of 15 t / h and air - 10 t / h. The initial pressure in the reactors is 0.4 kg / cm, which is ensured by

due to the low partial pressure of oxygen, limiting the rate of burning. The concentration of CO in the exhaust gases at the start of burning is 0.6%. As graphite burns, CO concentration decreases; using block 13, try to maintain this concentration unchanged, through regulator 11, increase the partial pressure of oxygen and, consequently, the burning rate. This leads to an increase in CO concentration and continued burning. Further, the CO concentration decreases again, by means of the regulator 1 it increases the oxygen pressure, etc. By the end of the outset dove; The lane is adjusted to 1.2 kg / cm, which ensures complete burning of graphite. The temperature in the reactors during the burning is maintained with the help of the regulator B at an average of 520 C.

The duration of the stages of burning in the proposed method tB h In prototype C, are approximately equal (L-TO h).

Stage catalyst development. Catalyst development is carried out to remove sulfur compounds, hygroscopic moisture, microstructure, and the like. Load of raw materials (isoamlens) 4 t / h and a pair of 15 t / h, .. air supply for regeneration 2 t / h.

The temperature is set using block 12: start with, then every hour raise it to and bring to 600 ° C. Thus, the duration of the development of Cpc, 5 (, 10 h.

The average yields of the target product (isoprene) over the development period: Praz)) 23% for the missing raw material; Rrazr 55% - on decomposed raw materials.

For the prototype, the rate of temperature rise is l C / h, therefore, the development time of the pa, h. The average inputs of the target product in the prototype over the development period are approximately equal to the outputs

ways: P

razr

23%;

The characteristic of the process for the mileage of the catalyst. This method allows us to increase the catalyst utilization, however, for simplicity, we will take it to be equal to the known: C 5 h.

In this case, the working step of the dehydrogenation according to the invention is:

 W P - Р ° totype: rc5 (e + pc, sp) 3870 h.

Dehydration is fed (Goaf) 8 t / h of raw materials (ioamylene), 30 t / h of steam and 3 t / h of air for regeneration,

In this method, the average output .5 for the working stage: P ,.

In the prototype, the average outputs for the working stage: Ррс ,.

Performance per mileage of the catalyst according to the invention: 5 "C-, e9er U

“Tr Art Pro. JP + G pwf -C p «s Pro (9417,2t.

For the prototype, the mileage performance of the catalyst is S "9033.6 tons, i.e. The proposed method provides an increase in productivity (at a constant consumption of raw materials) by 4.2%.

The table shows the data on the implementation of the proposed method in various conditions.

Claims (1)

Claims Sposbb of controlling the activation process of chromium calcium nickel phosphate cadal of a catalyst for dehydrogenating carbohydrate antennas, including controlling the steam / air mixture consumption at the stage of burning graphite and uniformly increasing the temperature from 540 to 600 ° C at the stage of catalyst development, characterized in and improving the quality of catalyst preparation, at the stage of graphite burning, the pressure of the para-air mixture above the catalyst layer is controlled, depending on the carbon dioxide concentration in the exhaust gases and the temperature in the reactors is maintained within 450-590 ° C; at a speed of 4-6 degrees / h. Fuel gas Waste gases Contact gas