JPH01203201A - Method for thermally decomposing gaseous hydrocarbon at high temperature - Google Patents

Abstract

PURPOSE:To make it possible to thermally decompose gaseous hydrocarbon at a lower temp. by using fibrous activated carbon as a filler. CONSTITUTION:When gaseous hydrocarbon such as methane is thermally decomposed into hydrogen and carbon at a high temp., fibrous or felt activated carbon is used as a filler. This activated carbon has a remarkably large surface are and the surface has been activated, so the activated carbon acts as a catalyst for a thermal decomposition reaction. Even when carbon deposits on the activated carbon, the activated carbon can be reutilized as the filler after reactivation or may be reutilized in other use after incineration or pulverization.

Description

[Detailed Description of the Invention] [Prior Art] The process of reducing carbon dioxide gas with hydrogen through the conventional Sabatier reaction and thermally decomposing the generated methane gas at high temperatures to convert it into hydrogen and carbon is shown in Fig. 4. explain.

The 9th acid gas mixed with hydrogen is passed through the Sabatier first reactor 2, which is filled with iron wire [7] and heated with a heater 4. After the produced water is removed with a condenser 5, the methane gas is passed through a silica wool 6. is charged and passed through the second Sabatier reactor 1 heated by a heater 3, where it is decomposed into hydrogen and carbon.

In this case, the reason why the glass wool 6 is filled into the Sabatier second dew reactor 1 for methane gas is to perform the catalytic action on the fiber surface of the silica rubble 6 and the supporting action of the carbon produced by the decomposition of the methane gas. Compared to the case where no filler is filled in the vessel 1, the decomposition reaction rate of methane gas is significantly increased, and carbon can be separated from hydrogen extremely easily.

[Problem to be solved by the invention]

In Sabatier's second reaction, which decomposes methane gas into hydrogen and carbon, the higher the reaction temperature, the higher the thermal decomposition efficiency, but as the temperature increases, power consumption increases, so raising the temperature extremely poses many practical problems. From the point of view of energy conservation, it is necessary to devise ways to increase the thermal decomposition efficiency at low temperatures.

Furthermore, most of the thermal decomposition of hydrocarbon gases such as methane is thought to occur on the surface of the filler, and for this reason, fillers in the form of fibers with a large surface area are desired.

Traditionally, silica wool was used as this filler, but
There is a demand for a filler with an even larger surface area.

Furthermore, since this thermal decomposition reaction is a chemical reaction, it is desired that the filler has a catalytic effect, but silica wool does not have a catalytic effect, which cannot meet the demand.

Furthermore, carbon generated by thermal decomposition precipitates on the surface of the filler, but if the filler is silica wool, the precipitated carbon cannot be easily separated, making it impossible to regenerate the filler. was there.

In view of the above-mentioned state of the art, the present invention provides a method for thermally decomposing hydrocarbon gas such as methane into hydrogen and carbon using a renewable filler that has a larger surface area than conventional silica wool, has a catalytic action, and is renewable. This is what we are trying to provide.

[Means to solve the problem]

The present invention is a high-temperature pyrolysis method for hydrocarbon gas characterized by using fibrous activated carbon as a filler in a high-temperature pyrolysis reactor.

Fibrous activated carbon, which is the filler used as a filler in the present invention, has a significantly higher surface area than silica wool (for example, as much as 150 m"/'l), and because the surface is activated, it has fewer pores. heat content of hydrocarbon gas)]
Acts as a catalyst for the reaction. Furthermore, even if carbon is precipitated in the fibrous activated carbon, it is the same carbon and can not only be reused for reactivation, but also be incinerated or pulverized and reused for other purposes.

The shape that can be used as fibrous activated carbon is fibrous activated carbon.
It can be felt-like or felt-like.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. The basic flow of FIG. 1 is the same as that of FIG. 4, and the same parts as in FIG. 4 are given the same reference numerals. 4 in Figure 1
What differs from the figure is that the filler packed in the Sabatier second reactor 1 is fibrous activated carbon rather than silica. , 8 indicates the fibrous activated carbon.

Among the results of comparing the flow in Figure 1 and the flow in Figure 4, the reaction temperature ('C) in Sabatier 2nd reactor 1
The relationship between and reaction rate (kg c (JH)) is shown in Figure 2. From Figure 2, it can be seen that at the same temperature, the reaction rate of the example of the present invention is higher than that of the conventional method.

Similarly, the ventilation time (E()) and pressure drop (m
Aq) is shown in FIG. From this figure 3, when the filling amount of the filler is the same and the ventilation gas flow rate is the same,
It can be seen that the embodiment of the present invention allows a larger amount of methane gas to be vented until the pressure drop is the same.

In addition to this, it was also confirmed that fibrous activated carbon can support a larger amount of precipitated carbon than silica wool.

〔Effect of the invention〕

The present invention has made it possible to carry out thermal decomposition of hydrocarbon gases at much lower temperatures.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the flow of one embodiment of the present invention, and FIG.
5 is a chart showing the effects of the present invention in comparison with the conventional method, and FIG. 4 is a two-row schematic diagram of the conventional thermal decomposition method for hydrocarbon gas. Country 1 Figure 2 Reaction temperature (0C)

Claims (1)

[Claims] A high-temperature pyrolysis method for hydrocarbon gas characterized by using fibrous activated carbon as a filler in a high-temperature pyrolysis reactor.