Method for producing hydrogen by reforming methanol steam

Abstract

The invention relates to a method for producing hydrogen by reforming methanol steam. The method comprises the following steps: taking methanol and water as raw materials, enabling the reaction temperature to be 410-460 DEG C, enabling the reaction space velocity to be 3000-23000h<-1> (calculated based on gaseous methanol), mixing the raw materials of the methanol and the water under the condition that the molar ratio of methanol to the water is 1: (0.8-2.0) for vaporization, then enabling the mixture to be in contact with a ZnO / ZnAl2O4 catalyst in a fixed bed reactor, generating reformed gaswhich is rich in the hydrogen, and separating the reformed gas by a palladium membrane separator for producing pure hydrogen gas. In the ZnO / ZnAl2O4 catalyst, the zinc-aluminum atomic ratio is more than 0.5: 1 and less than 2.5: 1. The method has the advantages of high reaction space velocity, high reaction conversion rate and low CO concentration, and the catalyst is simple to prepare, good in stability, low in cost and the like, thereby being particularly applicable to the process of integrating the hydrogen production by reforming the methanol steam with palladium membrane separation for preparing the pure hydrogen, and being capable of being used for industrial production process.

Description

technical field [0001] The invention relates to a method for producing hydrogen by steam reforming of methanol, in particular to a method for producing hydrogen by steam reforming of methanol by using zinc oxide / zinc-aluminum spinel as a catalyst, and belongs to the field of hydrogen production by reforming. Background technique [0002] Steam reforming of methanol to produce hydrogen (CH 3 OH+H 2 O→3H 2 +CO 2 ) of the prior art mostly adopt copper-based catalysts. The advantage of the copper-based catalyst is that it has good activity at low temperature, but it is easy to sinter at high temperature. There is also the direct loading of precious metal palladium on ZnO for methanol steam reforming reaction, which not only has good activity and high selectivity, but also resists sintering. But the high price of precious metals is not desirable. At present, the catalysts involved in the high-temperature methanol steam reforming hydrogen production method are mainly zinc / ch...

AI Technical Summary

Problems solved by technology

[0004] Zhao Biying and others (Acta Physicochemical, 1986, 2(2), 166-172; 2(6), 569-572) studied the ZnO / γ-Al prepared by impregnation method 2 o 3 System state and surface structure, γ-Al particles impregnated with zinc nitrate 2 o 3 , when the mass content of zinc oxide is greater than 2% (ZnO / ZnAl 2 o 4 Mole ratio 0.06) that appears crystalline phase ZnO, this study did not involve the details of the sample roasted at medium temperature, that is, ZnO / ZnAl suitable for use as a catalyst for high surface area 2 o 4 The system does not specify a clear composition and preparation method

And it is well known that the preparation of ZnO-Al by co-precipitation method 2 o 3 It is easy to generate spinel, and pure spinel has high temperature resistance. As a catalyst alone, its hydrogen production activity is low, and ZnO activity is high, but the preparation process of pure ZnO is easy to crystallize and grow. Therefore, to balance the advantages and disadvantages of the two, prepare a A hydrogen production catalyst that can be operated at high temperature and has high reactivity, no sintering and good stability is the core of the method of the present invention

Images