JP2000143210A - Carbon monoxide transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently obtain high purity hydrogen with compact and simple equipment by passing a reformed gas obtained by steam reforming of fuel for hydrogen production through a carbon monoxide reforming catalyst bed and providing a hydrogen separation chamber with a hydrogen separation membrane interposed in the boundary surface in the catalyst bed. SOLUTION: The flat carbon monoxide reforming catalyst bed 1 is sealed in a cubic casing 10 and a cooling device composed of water jackets 3 and 3 is arranged to be in close contact with the upper and lower sides thereof. The carbon monoxide reforming catalyst bed 1 is composed of a carbon monoxide reforming catalyst of an iron.chromium base or the like, the hydrogen separation chamber 8 is provided therein and the hydrogen separation membrane 2 composed of a thin film of palladium, a palladium alloy or the like is interposed in the boundary between the catalyst bed 1. The reformed gas obtained by the hydrogen reforming or the like of the fuel for hydrogen production flows in the carbon monoxide reforming catalyst bed 1 to react at 320-450 deg.C while being cooled by a cooling device to be converted to hydrogen. The hydrogen is selectively passed through the hydrogen separation membrane 2 to be taken out as pure hydrogen containing <=10 ppm CO from an outlet 5 of the hydrogen separation chamber 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a carbon monoxide converter.

[0002]

2. Description of the Related Art In a hydrogen production system or a fuel cell system, when producing a hydrogen-rich gas from a hydrocarbon or the like,
A carbon monoxide converter is used to reduce the concentration of carbon monoxide contained in the gas reformed by the reformer.

[0003]

In a hydrogen production system in which a hydrogen purifier is installed downstream of a reformer and a carbon monoxide converter to produce pure hydrogen, the area occupied by the hydrogen purifier increases. There is also a drawback that there are many working steps.

In a low-temperature operation type fuel cell such as a polymer electrolyte fuel cell, when hydrogen as a fuel contains a certain level or more of carbon monoxide, platinum used for an electrode is not used. It is poisoned and battery performance is reduced. Therefore, it is said that the carbon monoxide concentration needs to be 10 ppm or less. However, it is difficult to reduce the CO concentration to 0.1% or less by the method based on the carbon monoxide shift reaction. Therefore, a method of selectively adding CO to CO ₂ using a catalyst by adding a gas containing oxygen to the reformed gas (referred to as a method of selectively removing CO) is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-34601. It has been proposed in Kaihei 8-133702 and the like. However, these methods have complicated steps.

[0005] In addition, since the carbon monoxide conversion reaction is an exothermic reaction, the reaction proceeds more easily at a lower temperature, but there is a disadvantage that a lower reaction temperature results in a lower reaction rate.

The present invention has been made in view of the above points, and has been developed in a hydrogen production system and a fuel cell system.
It is an object of the present invention to provide a compact carbon monoxide converter having good performance.

[0007]

In order to achieve the above object, the present invention relates to a method for reducing the concentration of carbon monoxide contained in a reformed gas obtained by steam reforming of a hydrogen production fuel. In the carbon monoxide converter, a hydrogen separation chamber is provided in the carbon monoxide conversion catalyst layer, and a hydrogen separation membrane is interposed at a boundary between the hydrogen separation chamber and the carbon monoxide conversion catalyst layer.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a carbon monoxide converter according to the present invention, and FIG. 2 is a vertical sectional view on the II-II plane of FIG.

The carbon monoxide converter of the present invention shown in FIG. A cooling device is arranged. The carbon monoxide shift catalyst layer 1 is a horizontal, flat layer made of an iron / chromium-based carbon monoxide shift catalyst.
The hydrogen separation chamber 8 and the carbon monoxide shift catalyst layer 1
A hydrogen separation membrane 2 is interposed at the interface between the two. The hydrogen separation membrane 2 is formed of a thin film of palladium or a palladium-based alloy. Cooling water circulates through the water jackets 3 to adjust the temperature of the shift catalyst layer 1. A reformed gas inlet 4, a pure hydrogen outlet 5, a cooling water inlet 6, and a cooling water outlet 7 are provided outside the housing 10.

The above-configured carbon monoxide converter operates as follows.

As shown in FIG. 2, reformed gas obtained by steam reforming of various hydrogen-producing fuels flows into the shift catalyst layer 1 from the reformed gas inlet 4 and is converted into hydrogen. The reaction temperature at this time is about 320 to 450 ° C. The reaction temperature can be controlled by cooling water flowing from the cooling water inlet 6, circulating through the water jackets 3, 3 and flowing out from the cooling water outlet 7, so as to be in an optimum temperature range. The generated hydrogen permeates into the hydrogen separation chamber 2 in the direction of arrow H,
It is selectively separated, collected and flows out of the outlet 5. The reformed gas that has passed through the shift catalyst layer 1 is an off-gas outlet (not shown)
From the system.

In the above embodiment, the shift catalyst layer, the hydrogen separation chamber and the hydrogen separation membrane are described as being arranged horizontally, but they may be arranged vertically.

[0014]

As described above, according to the present invention, carbon monoxide conversion for reducing the concentration of carbon monoxide contained in a reformed gas obtained by steam reforming of a fuel for hydrogen production or the like. In the vessel, the hydrogen separation membrane was installed in the carbon monoxide shift catalyst layer, so that the following excellent effects were obtained. (1) The hydrogen production system does not require a hydrogen purifier. That is, the hydrogen production system can be simplified. (2) In the fuel cell system, the CO selective oxidizing device becomes unnecessary. That is, the hydrogen production system can be simplified. (3) The CO concentration can be reduced to 10 ppm. (4) By using the hydrogen separation membrane, hydrogen can be selectively separated from the reformed gas. Therefore, the reaction can be promoted by breaking the reaction equilibrium.

[0015]

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a schematic configuration of a carbon monoxide converter according to the present invention.

FIG. 2 is a vertical sectional view on a II-II plane of FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 carbon monoxide shift catalyst layer 2 hydrogen separation membrane 3 water jacket 4 reformed gas inlet 5 pure hydrogen outlet 6 cooling water inlet 7 cooling water outlet 8 hydrogen separation chamber 10 housing

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshinori Shirasaki 2-13-7-604 Midori, Sumida-ku, Tokyo (72) Inventor Tetsuya Imai 4-6-22 Kanon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Sanishi Heavy Industries, Ltd. Hiroshima Research Institute (72) Inventor Kazuto Kobayashi 4-6-22 Kanon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd. F-term in Hiroshima Laboratory, Mitsubishi Heavy Industries, Ltd. (reference) 4G040 FA02 FB04 FC01 FC07 FE01 4G069 AA02 BC58A BC66A CB07 CC32 5H027 AA06 BA01 BA16 BA17

Claims (1)

[Claims] 1. A carbon monoxide converter for reducing the concentration of carbon monoxide contained in a reformed gas obtained by steam reforming of a fuel for hydrogen production, etc. A carbon monoxide converter, comprising: a hydrogen separation chamber; and a hydrogen separation membrane interposed at a boundary between the hydrogen separation chamber and the carbon monoxide conversion catalyst layer.