JPH0374493A - Carbon monoxide modifying method in town gas-producing plant and equipment therefor - Google Patents

Abstract

PURPOSE:To uniformly and efficiently convert CO in a town gas generated in a reactor to safe CO2 by flowing heat medium in paths connecting between plural stages of CO-modifying catalyst layers in series and indirectly cooling a town gas. CONSTITUTION:A preheater 4 indirectly cooling a town gas carrying reaction heat generated at converting and modifying CO to CO2 is installed in paths 9 connecting between plural stages of CO-modifying catalyst layers 8 such as a copper-zinc system or an iron-chromium system. By said system, a town gas having risen temperature by reaction is indirectly cooled by a heat medium such as air, water or steam flowing through a pipe of the preheater 4 and temperature of a town gas itself is returned to a temperature suitable for reaction.

Description

[Detailed Description of the Invention] (Industrial Application Field) When petroleum-based raw materials such as naphtha and LPG are gassed, the city gas produced contains a large amount of carbon monoxide, approximately 20%. Therefore, as stated in the legal regulation of 6% or less,
This needs to be treated with non-toxic C.

Detoxification is achieved by using an iron-based catalyst for the conversion of -acid to arsenic carbon.
A high-temperature shift conversion method performed at a temperature of 0 to 500°C or a low-temperature shift conversion method performed at a temperature of 100 to 350'C using a copper-based catalyst is attached to the city gas production plant system. ``This is done by converting arsenic carbon into carbon dioxide.

The present invention relates to a carbon monoxide conversion method and apparatus for such cyclic or continuous city gas production.

(Prior Art) A high-temperature metamorphosis method for converting carbon monoxide in generated city gas into carbon dioxide is known, for example, from Japanese Patent Application Laid-Open No. 1983-1992, which was made by the applicant.
There is an invention disclosed in Japanese Patent Publication No. 157896, and a low-temperature metamorphism method is disclosed in Japanese Patent Publication No. 63-20277, for example.

By the way, the reaction of converting -carbon oxide into carbon dioxide is accompanied by heat generation. However, the above inventions all depend on the temperature of the catalyst layer where the reaction takes place! II adjustment has not been performed.

(Problems to be Solved by the Invention) In the conventional carbon monoxide conversion method in city gas production plants, the heat generated by the reaction raises the temperature of the catalyst layer above the appropriate reaction temperature, making it difficult to continue and maintain high efficiency reactions. Moreover, since the strength of the catalyst itself is weak and self-destruction makes it difficult to stack the catalyst layers in a high pile, it has been difficult to process gases with high efficiency and large capacity.

Furthermore, the heat generated by one reaction was dissipated without being effectively utilized.

Therefore, the present invention aims to solve the problem of monoacid f contained in a large amount of city gas.
The present invention provides a carbon monoxide conversion method for a city gas production plant and an apparatus for converting carbon monoxide into carbon dioxide with continuous high reaction efficiency and also recovering the heat of one reaction.

(Means for Solving the Problems) The present invention provides a carbon monoxide shift conversion system in which carbon monoxide shift catalyst layers are partitioned into multiple R stages and are indirectly cooled in a prefecture of a city gas production plant. City gas containing a large amount of moisture and carbon monoxide produced in the reactor of a city gas production plant is introduced into the carbon oxide conversion equipment, and the harmful carbon monoxide is converted into carbon dioxide. The aim is to supply city gas to the public that has been detoxified after undergoing heat and dilution processes.

In addition, the carbon oxide shift device has a catalyst layer partitioned into multiple stages into which generated city gas is introduced, a path connecting the catalyst layers partitioned into multiple stages in series, and a heat medium passed through the path. This type is equipped with a preheater that indirectly cools city gas.

(Function) By the method described above, the heat generated from the reaction of converting carbon oxide to carbon dioxide is carried by city gas and indirectly heated in a preheater installed in the path between each carbon oxide conversion catalyst layer. Since the catalyst is cooled and heat is recovered, each catalyst layer partitioned into multiple stages is always at a temperature suitable for the reaction, allowing a highly efficient reaction to continue.

Further, the heat generated in each carbon oxide conversion catalyst layer due to the reaction is indirectly cooled by a heat medium such as water, air, or steam in a preheater, and the heat obtained by the heat medium is recovered. This recovered heat is effectively used for preheating water or steam required for the conversion of carbon oxide, or as a heat source for producing steam necessary for the reaction of generating city gas.

- By indirectly cooling the catalyst layer for carbon oxide conversion using a heat medium without directly cooling it with water or steam, damage to the catalyst can be prevented, and the catalyst layer can be prevented from being clogged due to damage to the packed catalyst. will not occur.

By forming the carbon monoxide conversion catalyst layer in multiple stages, it is easy to adjust the required carbon monoxide concentration after the reaction, and the undulating catalyst layer also prevents leakage. Short baths and catalyst self-destruction do not occur.

(Example) FIG. 1 shows a flow sheet of an example of the low-temperature carbon oxide conversion method for a cyclic city gas production plant according to the present invention.

The city gas produced in the reactor 1 is cooled in the waste heat boiler 2 to adjust the gas temperature, and then introduced into the low-temperature carbon oxide shift converter 3. Although not shown, the city gas is converted into heat caloric value after exiting the water sealer 5. After passing through the scrubber 6, the gas is diluted and adjusted for thermal calorie content, and then stored in a gas holder and supplied to the public as city gas.

The make period for producing city gas is carried out by the above-mentioned process, and during the heat period for raising the temperature of the reactor for producing city gas, the residual heat of the flue gas that heated the reactor 1 is recovered by the waste heat boiler 2. After that, it is released into the atmosphere from the chimney 7 as exhaust gas.

City gas is manufactured by repeating this heat period and make period, that is, by cyclically.

The low-temperature carbon oxide converter 3 first divides and partitions the tower into a plurality of stages, and each stage is filled with a carbon monoxide transformation catalyst that converts carbon monoxide into two carbons. Catalyst layer 8.
form 8.

11th! ? In the case of Example 1, the low temperature range is from 100°C to 35°C.
Although it was formed by providing a catalyst layer 8.8 packed in two stages with a copper-zinc-based low-temperature catalyst suitable for temperatures around 0°C, the high-temperature region 3
Catalyst layer 8.8 filled with two stages of iron-chromium-based high-temperature catalyst suitable for temperatures from about 00°C to 500°C, or
The catalyst layer 8.8 is filled with a high-temperature catalyst in the upper layer and a low-temperature catalyst in the lower layer, or the reverse combination, or three or more catalyst layers 8 as shown in FIG. Form into stages to form a combination suitable for each plant.

A path 9 is provided that connects each of the catalyst layers 8 and 8 in series, and through the path 9, city gas is indirectly supplied which carries the reaction heat generated when converting -acid f arsenic carbon to dicarbon arsenic carbon. A cooling preheater 4 is provided, and the city gas whose temperature has risen due to the reaction is indirectly cooled by a heating medium such as air, water, or steam passing through the preheater 4 pipe, and the city gas itself is brought back to a temperature suitable for the reaction. Form it back.

The heat recovered by indirectly cooling the heated city gas can be used as heat for preheating a waste heat boiler to increase the generation of steam used for city gas production, or as heat for preheating combustion air. When used effectively as a heat source, an example of the test results of the device population and outlet of the two-stage low-temperature-carbon oxide shift device of the cyclic city gas production plant according to the present invention shown in the flow sheet of Fig. 1 is shown below. Shown in the table.

Table: In this case, city gas produced in reactor 1 is cooled through waste heat boiler 2, and reaches a temperature of about 180'C in low-temperature carbon oxide conversion system W3, and the temperature is about 180'C in the low-temperature carbon oxide conversion system W3. In the catalyst layer 8, a primary conversion reaction of -carbon oxide to carbon occurs at about 240°C, which is cooled to about 160°C in the preheater 4 to reach a low temperature in the lower stage. - introduced into the catalyst layer 8 of the carbon oxide conversion catalyst;
A secondary conversion reaction is carried out, and the city gas at about 260° C. is discharged from the outlet of the low-temperature carbon oxide shift device 3.

In addition, carbon monoxide in city gas was reduced from about 21.4% to about 2.5%, maintaining a high conversion rate of over 90%.

<Effects of the Invention> As described above, the present invention is capable of continuously maintaining each of the carbon oxide shift catalyst layers partitioned into multiple stages at a temperature suitable for the reaction, and furthermore, the heat generated by the reaction can be used for preheating. Highly efficient and stable as it can be used effectively as a heat source such as
This makes it possible to transmute carbon, making it a durable and economically superior facility for city gas production plants.

In addition, indirect cooling is used to cool each of the carbon oxide shift catalyst layers, which are partitioned into multiple stages, so there is no clogging due to damage to the packed catalyst, and maintenance is easy and the temperature is uniform and high. Efficient reactions can be continuously maintained.

In addition, detoxified city gas will contribute to the safety of gas users.

[Brief explanation of drawings]

FIG. 1 is a process flow sheet in which a two-stage low-temperature carbon oxide shift apparatus is applied to a cyclic city gas production plant, showing an example of actual TI and oxidation according to the present invention. Second
The figure is a schematic explanatory diagram of a carbon monoxide conversion equipment in which the -carbon oxide conversion catalyst layer is arranged in three stages. l...Reactor 2...Exhaust heat boiler 3...
・・・-Carbon oxide conversion equipment

Claims (2)

[Claims] (1) A process is provided to indirectly cool city gas by passing a heat medium through a path that connects in series between multiple stages of carbon monoxide conversion catalyst layers that are partitioned, so that city gas containing moisture generated in a reactor can be cooled. A carbon monoxide conversion method for city gas production plants that converts carbon monoxide inside into carbon dioxide. (2) City gas is indirectly cooled through heat exchange using a plurality of partitioned carbon monoxide conversion catalyst layers, a path connecting the plurality of catalyst layers in series, and a heat medium in the path. A carbon monoxide shift device for a city gas production plant, characterized in that it is equipped with a preheater.