CS277274B6 - Pipe system of reaction sections of primary steam reforming furnace - Google Patents

Abstract

The tube system of the reaction sections of the primary steam reforming furnace is used in the petrochemical industry for the chemical conversion of hydrocarbon molecules into a mixture of hydrogen and carbon oxides. In the radiation chamber /1/ with burners /2/ there is a system of parallel vertical reaction tubes /3/. The reaction tubes /3/ are interconnected by an outlet collector /4/, located under the bottom /9/ of the radiation chamber /1/. The outlet collector /4/ consists of a thin-walled non-pressure tube /6/, insulating material /7/ and a pressure jacket /8/. A riser /5/ is led out from the center of the outlet collector /4/.

Description

The present invention relates to a tubular system of reaction sections of a primary steam reforming furnace which are used in the petrochemical industry in the chemical conversion of hydrocarbon molecules to a mixture of hydrogen and carbon oxides.

A catalytic, generally endothermic reaction takes place in the reaction sections of these furnaces. The preheated mixture of hydrocarbons with water vapor flows through a system of parallel tubes filled with catalyst. The tubes are placed vertically in a combustion radiation chamber, in the ceiling of which there are injector gas burners. Here. the fuel energy released is used to further heat the reaction mixture and to cover the heat of reaction required. This energy is transmitted mainly by radiation from the flue gas to the outer surface of the reaction tubes. The flue gases leave the radiation section with a temperature of approx. 1,050 ° C, the reaction mixture emerges from the reaction tubes with a temperature of approx. 830 ° C. The gas leaving the system of vertical reaction tubes is collected by a so-called horizontal outlet collector, which is firmly connected to the reaction tubes. When heated to operating temperature, the reaction tubes lengthen by approx. 150 mm due to thermal expansion. To compensate for this expansion, the reaction mixture is passed through a riser located in the middle of the outlet collector and also through a radiation section in the plane of the reaction tubes. The riser passes through the ceiling of the radiation chamber and opens into the manifold. ·

In the present embodiment, the outlet horizontal collector is insulated in order to reduce its design temperature, which is then only slightly higher than the temperature of the flowing medium. The insulation material is produced in precise shaped pieces and glued to the collector tube with glue. The insulation material is secured against falling off the collector along the entire length and perimeter of the collector by a sheet metal cover tightened with cable ties. Sheet metal and cable ties are made of high-alloy material.

This solution for insulating the outlet collector has drawbacks in that the sheet metal protective cover is considerably damaged or in some cases destroyed after about 2 to 3 years of operation.

The outlet collector itself, made of highly alloyed material, is operated at a design temperature of 850 ° C and a design overpressure above 3 MPa. Its service life depends on the observance of many technical operations, both during installation and operation, in order not to introduce unwanted secondary bending stresses or to overheat it. In summary, the outlet collector, including its insulation, is a delicate and vulnerable part of the pipe system of this furnace.

The above-mentioned drawbacks are eliminated by the tubular system of reaction sections of the primary steam reforming furnace, the essence of which is the transfer of the outlet collector under the bottom of the radiation chamber of the furnace. The outlet collector is formed by a pressure jacket in which a thin-walled non-pressure pipe is insulated with insulating material. This changes the pressure part of the outlet collector from hot to cold and from high-alloy to non-alloyed with a design temperature of around 300 ° C.

CS 277274 B6 2

The drawing shows an example of a pipe system according to the invention. Fig. 1 is a detail of the connection of the outlet collector with the riser, Fig. 2 shows a pipe system according to the invention in a vertical section.

In the radiation chamber 1 with the burners 2 there is a set of parallel vertical reaction tubes 3. The reaction tubes 3 are connected by an outlet collector 4 located below the bottom 9 of the radiation chamber 1. The outlet collector 4 is formed by a thin-walled non-pressure tube 6, insulating material 7 and a pressure jacket 8. A riser 5 is led out of the center of the outlet collector 4. the insulating material 7 may be concrete or other material with the required insulating properties.

Claims (2)

PATENT CLAIMS A tubular system of reaction sections of a primary steam reforming furnace, consisting of a system of parallel vertical reaction tubes which are connected by an outlet collector, from the center of which a riser is led out, characterized in that the outlet collector (4) is located below the bottom (9). chambers / 1 /. 2. The tube system of the reaction sections of the primary steam reforming furnace according to item 1, characterized in that the outlet collector / 4 / is formed by a pressure jacket / 8 /, in which there is a thin-walled non-pressure tube / 6 / with insulating material / 7 /.