The reaction element of heterogeneous-catalytic reactor

 

(57) Abstract:

The reaction element of the reactor relates to a device for the implementation of heterogeneous catalytic reactions, particularly reactions of steam reforming of hydrocarbons. Made in the form of a highly porous material with a set of cells. Jumper cells highly porous material provided with a catalytically active coating, and the material of the reaction element occupies the entire volume of the reactor and is rigidly connected with its heat transfer walls. This design provides additional strength and allows to intensify the process of evaporation. 2 Il.

The invention relates to a device for the implementation of heterogeneous catalytic reactions, particularly reactions of steam reforming of hydrocarbons. It allows you to utilize the heat of heat-stressed structural elements and to obtain a hydrogen-containing gases.

The invention can be used in the construction of transport and stationary energy, chemical and other industries.

Known catalytic element for the fixed catalyst layer in the channels of heterogeneous-catalytic reactor (author swollen as spatially deformed plate with a catalytic active layer on its surface. The plate is deformed relative to the larger of the axis of symmetry at an angle 90-180o. The ratio of the width of the plate to the diameter of the reactor is 0.1 to 0.7. Plate made of sheet material with high thermal conductivity that is loaded in the channel of heterogeneous-catalytic reactor and thereby form a porous permeable layer. Due to the fact that the plate is made from a material with high heat conductivity, the effective conductivity of the layer is high enough.

However, the lack of hard contact plates with the wall of the reactor and between them does not allow full use of thermal conductivity of the material of the plates. Moreover, during operation of the reactor due to pollution free contacting surfaces of the contact between them will be reduced and thermal resistance to increase. Additionally, breach of contact will occur when the reactor is installed on the vehicle when the shaking and vibration of the device. All this will inevitably lead to a decrease in the intensity of heat and mass transfer.

Also known reactionary element of the apparatus for catalytic conversion of methane from the description to the author's certificate of the USSR 1780826, IPC B 01 J 8 is with a gap relative to the inner surface of the pipe is fixed catalyst. The reaction element provided with a perforated insert coaxially and with a gap that is installed on the catalyst.

The outer surface of the insert provided with a catalytically active coating. The coating can be performed by plasma spraying powder of metallic Nickel on the surface of the insert. The catalytically active coating of the insert allows to intensify the total heat transfer from the outer pipe to insert and to the flow of the reacting mixture and to intensify the process of thermochemical accumulation of thermal energy through the creation of the cross-section of the annular channel of the optimal profiles of temperature and concentration fields.

In this analogue warmth to the surface of the catalyst and the catalytic surface of the perforated insert for carrying out a chemical reaction is served only by convection from the heated wall. The intensity of heat transfer in comparison with the stated reaction element of the low.

Of all known analogues closest to the proposed invention to the technical essence and the achieved effect when using it is a reactionary element, known from the description to the author's testimony 1710117, IPC B stny reactionary element heterogeneous catalytic reactor with a fixed catalyst bed in the form of metal mesh tube, mounted on the frame coaxially of the reaction tube. Metal mesh tube composed of a series of successive layers with a catalytically active layer and increasing from the inner layer to the outer step of the cell.

Reactionary elements are loaded into the reaction tube in an amount necessary for the desired degree of completion of the reaction of steam reforming. Due to the fact that the reaction element is made of a set of grids with high conductivity, temperature gradient on the layer of catalyst is minimal, despite the high indeterminate reaction.

The temperature of the inner layers of mesh reactionary element practically does not differ from the temperature of the outer layer. The efficiency of the internal layers of the catalyst is comparable with the efficiency of the outer layers.

Intensifitsirovany heat transfer from the wall of the reaction tube is due to the layered execution of the reaction element.

However, in the prototype there is a cascade of thermal resistances from the heated wall to gas, from gas to the outer surface of the mesh tube from the outer surface to the inner surface of the pores. The heat transfer from the reaction heated tritace high. In addition, the gap between the reaction tube and the reaction element is not possible to use the latter as a power of the structural element.

The technical task to be solved by the invention is a significant intensification of the process of heat and mass transfer and ensuring minimal temperature gradients in the reactor, as well as providing additional structural strength.

Declared reactionary element, as a prototype, is a porous permeable material with a set of cells bounded by the walls of heterogeneous catalytic reactor.

Unlike the prototype, the reaction element is designed as a highly porous cellular material (ITAM), three-dimensional cell which is formed by a metal edge ridges, creating a rigid frame reactionary element. Jumpers have a catalytically active coating. Highly porous cellular material is rigidly connected with the heat transfer wall of heterogeneous-catalytic reactor.

The stated set of essential features when using the invention ensures the supply of heat to the catalytically active coating m the strict frame of the reaction element. This allows significantly intensify the heat transfer in a chemical reaction and to provide a minimum temperature gradients in the reactor.

The invention is illustrated by drawings, where:

- Fig.1 shows a cross-section of heterogeneous-catalytic reactor rectangular cross-section with the stated reaction element;

- Fig.2 - site And in a larger view.

Declare the reaction element, as a prototype, is a porous permeable material with a set of cells 1, bounded by the walls 2 heterogeneous catalytic reactor. Unlike the prototype, the reaction element is designed as a highly porous cellular material (ITAM), rigidly attached (soldering, welding, etc.,) to the walls of the reactor. ITEM has a three-dimensional pentagondodecahedron three-dimensional structure, cell 1 which is formed of metal ribs-jumpers 3, creating a rigid frame reactionary element. Metal jumper 3 have high conductivity and are catalytically active coating 4.

Heterogeneous catalytic reactor with the reaction element operates as follows.

The original gas-vapor mixture with 1 (1-5) mm and an open porosity of 0.80-0,98 has a low hydraulic resistance to flow of a chemically reactive gas, and the high conductivity metal jumpers 3 and homogeneity of ITEM provide uniform volume of reactor heat transfer from the heated wall 2. Necessary for carrying out the endothermic reaction heat is supplied to the catalytically active coating 4 is not only due to the convective heat transfer, but also by conduction to the frame of the reactionary element that allows significantly intensify the process of heat transfer and to ensure minimal temperature gradients in the reactor.

The rigid connection of the reaction element with walls 2 heterogeneous-catalytic reactor gives his design for extra strength, due to the high mechanical properties of ITEM due to the three-dimensional structure. The reaction element of ITEM may be made of any shape (round, square, etc.,) depending on the shape of the surface to be cooled.

The present invention can be used for the disposal of heat loss through the walls of the apparatus, and with the leaving gases. Tallapragada part construction is one of the walls of heterogeneous-catalytic reactor, which is, for example, kleweno heat Q=6,6 MJ/kg, equal to the heat of reaction, and the resulting molecular hydrogen H2being environmentally friendly fuel. Held in our company calculations and experimental work confirmed the possibility of removing large heat loads from heat-stressed structural elements.

The reaction element heterogeneous catalytic reactor, made in the form of a highly porous material with a set of cells, wherein the jumper cells highly porous material provided with a catalytically active coating, and the material of the reaction element occupies the entire volume of the reactor and is rigidly connected with its heat transfer walls.

 

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