SU594626A1 - Method of performing chemical reactions - Google Patents

Description

In the diagonal direction, a gas flow exists and develops along the height of each catalyst layer, therefore, the rate of heat transfer increases and the gas cross section averages across the pipe. In addition, the rate of transfer of the source gas to the reaction zone, reaction products from the reaction zone, and heat to the reaction zone increases. .

Example 1. A annular nickel catalyst with an outer diameter of 10 mm, 15 mm, 20 mm is loaded into the reaction tube with a diameter of 98 mm and a height of 8 m of a tubular furnace according to a quasi-sinusoidal law. Catalyst layers of each size with a height of 400 mm are loaded in the following order:

1st layer - granules with an outer diameter of 10 mm; 2nd layer - 15 mm; 3rd layer - 20 mm; 4th layer - 15 mm; 5th layer - 10 mm; 6th layer - 15 mm; 7th layer - 20mm it.t. d:

Total load 20 layers of catalyst.

The proposed multilayer loading, which alternates layers with granules of 3 sizes, ensures interruption of the channels at the points of contact of adjacent layers and prevents the formation of through channels along the entire length of the pipe.

A mixture of methane and water vapor at 480 ° C and a vapor-gas ratio of 4: 1 is fed into the reaction tube. Methane consumption is 95. The gas mixture passes sequentially through the 1st catalyst bed, the 2nd layer, the 3rd layer, the 4th layer, and so on. 20 catalyst layers.

The hydraulic resistance of the 4acTeiJ layers located closer to the pipe axis varies from layer to layer much less than the parts of the layers located at the pipe wall. The larger the diameter of the granules, the smaller the resistance of the parts of the layers located at the pipe wall. Therefore, when the gas mixture passes from the first layer to the second layer and further as it moves along the second layer, the gas mixture moves in the radial direction to the pipe wall. When the gas mixture passes into the third layer and then as it moves in the third layer, the mixture continues to move radially to the wall of the pipe, and the flow rate of the gas mixture closer to the pipe axis and near the wall reaches its minimum and maximum values, respectively. Due to this radial movement of the gas, the flows of the colder parts of the gas mixture, which are closer to the pipe axis, are mixed with the hotter ones located at the pipe wall.

The rate of heat transfer increases, so the average temperature of the gas mixture increases, as a result of which the degree of chemical reaction increases. In addition, mixing the gas mixture, due to the movement of the gas mixture in the radial direction, leads to an increase in the rate of transfer of the reaction products from the reaction zone and into the reaction zone of the gas mixture and an increase in the rate of heat transfer to the reaction zone. Upon further movement of the gas mixture in the fourth, fifth, and sixth layers, gas begins and develops in the radial direction from the pipe wall to the axis. With

This effect on the conversion of methane radial movement of the gas mixture from the pipe wall to the axis is similar to the movement of the gas mixture to the pipe wall.

In the following layers, the gas mixture also changes its direction as described. From the 20th layer of the catalyst gas mixture comes out with a temperature of 800 ° C, a pressure of 25 MPa and composition. %: 3.47 CH4; 6.13 CO2; 43.2 PzO; 41.5 On; 5.68 SB.

This method compared with the analog. M with the same consumption of methane, the ratio of the gas-vapor mixture and under the same conditions of the gas-vapor mixture at the entrance to the reaction tube provides an increase

hydrogen output at 4 vol. % and a decrease in the residual methane content

2%, which indicates a significant increase in the degree of chemical reaction and, accordingly, the performance of hydrogen.

Example 2. The intensification of the processes of heat and mass transfer also takes place during the reaction of the catalytic conversion of propylene to acrolein in a tube loaded with alternating layers of a spherical catalyst.

In a pipe with an internal diameter of 20 mm

have loaded 35 layers of catalyst

by, 100 mm of the following sizes:

1st layer - 3 mm; 2nd layer - 4 mm; 3rd

layer - 6 mm; 4th layer - 4 mm; 5th layer -

3mm; 6th layer - 4 mm, etc.

The pressure and temperature of the gas mixture at the inlet to the pipe is 4 MPa and 250 ° C. The composition of the mixture at the inlet, weight. %: 92.8 SzNb and 2.7 Og. Weight consumption of the mixture is 35,500 kg / h m2.

The composition at the exit of the pipe loaded with alternating catalyst layers was compared with the same composition with a single-layer catalyst loading of 4 mm in size in a pipe of the same diameter under the same conditions at the entrance to the pipe.

The amount of residual oxygen on

at the exit of the pipe with multilayer loading 4.54%, and with single-layer loading

4.78%

Claims (2)

The decrease in the percentage of residual oxygen is explained in the same way as in the previous example: when going from a catalyst bed of the same size to a catalyst bed of a different size, the hotter flows of the reaction mixture are mixed with the colder ones, the average (over the cross section) temperature of the mixture increases, the temperatures increase. chemical reaction rates and 5 processes of heat and mass transfer. All this leads to an increase in the degree of chemical reaction. Claim 5 A method of conducting a chemical reaction by passing a gas through a multilayer catalyst with varying the size of the granules in layers in the reaction tube, which differs from -10 in order to increase the specific productivity and yield of the target product, changing the size of the catalyst granules in sequential 59462 6 6 layers along the gas flow are carried out according to a quasi-sinusoidal law, and the height of each layer of catalyst granules is no more than 2-5% of the total length of the reaction tube, but not less than ten sizes catalyst pellets. Sources of information taken into account in the examination: 1. Vakk E. G. and Semenov V. P. Catalytic conversion of hydrocarbons in tube furnaces. M., “Himi, 1973. 2. US patent No. 2006078, CL. 23-288, 06.25.35.