Catalyst for selectively oxygenizing CO in hydrogen-rich gas and preparation method thereof

Abstract

The invention provides a CO selectively oxidization catalyst in hydrogen-rich gas, which consists of 0.5 to 2 percent of Ru and 5 to 15 percent of accessory ingredient by weight percentage loaded on gama-Al2O3, wherein the accessory ingredient can be K2O, Li2O, Fe3O4 or LA2O3. In the catalyst, noble metal has small content, but has over 50 percent of selectivity to CO, has higher conversion rate under a wider reaction temperature range (100 to 200 DEG C) and gas space velocity (8,000 to 14,000 hour<-1>, and can reduce the content of CO in the hydrogen-rich gas containing 1 percent of CO to 100ppm, even lower than 10ppm.

Description

technical field [0001] The invention relates to the field of inorganic chemistry, in particular to the purification of hydrogen-containing gas. Background technique [0002] Proton exchange membrane fuel cell is a high-efficiency, pollution-free power generation device that utilizes the principle of electrochemical reaction and uses hydrogen or hydrogen-rich gas as fuel. It is the most promising power source for electric vehicles. Liquid fuel, such as methanol, gasoline, etc., is converted into hydrogen through a portable reformer to provide fuel for fuel cell electric vehicles, which solves the inconvenience of pure hydrogen fuel in vehicle, storage and transportation. Methanol is liquid at room temperature, easy to transport, can generate hydrogen at relatively low temperature (200-400°C), easy to operate, sulfur content is less than 5uL / L, has high energy density, and the mileage of one refueling can reach Comparable to traditional internal combustion engine vehicles, it...

AI Technical Summary

Problems solved by technology

Although non-noble metal catalysts are active at lower temperatures, they cannot remove CO from hydrogen-rich gases well.

Patent WOO160738 A2 (August 23, 2001) provides a series of Cu x Ce 1-x o 2-y (x=0.01~0.3, y≥x, x and y are both molar ratios), but this catalyst cannot reduce the CO in the simulated gas containing 1vol% CO to less than 100ppm, and the actual reformed gas with the presence of water vapor has not been studied Catalyst performance in

In Applied Catalysis A (General) 232 (2002), 107-120, the author used the impregnation method to prepare CuO / CeO doped with samarium oxide 2 Catalyst, the gas ratio is H 2 :O 2 : CO = 97: 2: 1 shows better CO catalytic performance, due to the large discrepancy between the gas in the experimental study and the reformed gas, it cannot yet reflect the actual working conditions of the fuel cell

CuO-CeO mentioned in the paper published by Ratnasamy et al. in Journal of Catalysis 221(2004), 455-465 in 2004 2 -ZrO 2 catalyst, at a temperature of 175 °C, O 2 Under the condition of / CO being 1.25, the 0.49% CO in the hydrogen-rich gas is reduced to 140ppm, but the conversion rate and selectivity of the catalyst are low, and the temperature range of the catalyst is less than 25°C

In International Journal of Hydrogen Energy, 30(2005), 59-66, Park et al. made catalyst Cu-Ce / Al 2 o 3 In 1% CO, 1% O 2 , 60%H 2 and 38%N 2 Under the gas composition, when the temperature range is 175-220 °C, the conversion rate is >99%, but the catalyst is more prone to deactivation, water and CO 2 The existence of has a considerable negative impact on its

[0005] For the platinum-based catalysts that have been studied more recently, their performance is relatively stable, but their low-temperature activity is low, and oxygen gas that far exceeds the stoichiometric ratio is required, so there is unnecessary hydrogen consumption.

Chinese patent CN1426959A discloses a Pt catalyst loaded on Y-type zeolite or ZSM zeolite. The catalyst is used when the molar ratio of oxygen to CO is 1-2, and the reaction temperature is between 120-200°C, and its CO conversion rate is close to 100. %, but the content of Pt in this type of catalyst is as high as 3% (weight)

In response to this problem, the Chinese patent CN1397485A has improved the above technology, using γ-Al 2 o 3 As a carrier, Li, Na, K and other additives are added, so that the Pt catalyst can still reduce CO to below 100ppm when the content is less than 2%, but the oxidation selectivity of the catalyst is low (only 30~ 40%)