A low-temperature sulfur-tolerant shift catalyst and its preparation method

Abstract

The invention relates to a low-temperature sulfur tolerant shift catalyst and a preparation method thereof. The low-temperature sulfur tolerant shift catalyst comprises the following components based on the total weight of the catalyst: 2-6wt% of cobalt oxide, 3-12wt% of molybdenum oxide, 1-15wt% of alkali metal or alkaline-earth metal aids and the balance of a double-peak pore distribution type alumina-based carrier, wherein the carrier consists of gamma-Al2O3, TiO2 and ZrO2; by taking the weight of the carrier as the reference, the content of the gamma-Al2O3 is 56-75wt%, the content of the TiO2 is 3-22wt% and the content of the ZrO2 is 10-22wt%; the pore volume of the catalyst is 0.80-1.20ml / g, and the specific surface area of the catalyst is 100-180m<2> / g; the pore volume with the pore size of less than 50nm in the carrier accounts for 55-65 percent of the total pore volume; the pore volume with the pore size of 150-500nm accounts for 20-30 percent of the total pore volume; and the pore volume with the pore size of more than 500nm accounts for less than 10 percent of the total pore volume. The catalyst is used for a medium-pressure low-temperature sulfur tolerant shift hydrogen production process and has high low-temperature activity, long service life and excellent hydrogen production yield.

Description

technical field [0001] The invention relates to a low-temperature sulfur-resistant shift catalyst and a preparation method thereof. Specifically, the invention relates to a low-temperature sulfur-resistant shift catalyst containing a bimodal pore distribution type alumina-based carrier and a preparation method thereof. Background technique [0002] At present, carbon monoxide-containing gas produced from heavy oil, vacuum residue or coal usually contains sulfide, and its content is related to the sulfur content of the raw material, generally between hundreds to thousands of ppm. Coking coal gas For example, its H 2 S content up to 7.8g / m 3 , organic sulfur about 100mg / m 3 . The most commonly used shift catalysts in the prior art are Fe-Cr-based high-temperature shift catalysts and Cu-Zn-based low-temperature shift catalysts, but these two types of catalysts are sensitive to sulfides and are prone to sulfur poisoning, so they cannot be applied to high-sulfur-containing cat...

AI Technical Summary

Problems solved by technology

Existing Co-Mo-based sulfur-tolerant shift catalysts are mainly divided into two categories, one of which is the non-alkali metal Co-Mo / Al disclosed in US3957962A 2 o 3 Base-shift catalysts, although this type of catalyst has good sulfur resistance performance, its low-temperature activity is not ideal, and the catalyst activity declines seriously under medium pressure or high water vapor partial pressure conditions

[0004] The second is the Co-Mo based shift catalyst disclosed in US3850840A containing an alkali metal as a promoter. Although this type of catalyst has the advantages of high low-temperature activity, insensitivity to poisons, and a wide range of requirements for the sulfur content in the feed gas, the use process Medium alkali metals, such as potassium, are easy to lose, which leads to a serious decline in catalyst activity

[0005] Chinese patent CN1045399C discloses a non-alkali metal Co-Mo based sulfur-tolerant shift catalyst, which has high low-temperature activity and good adaptability to high space velocity and low water-vapour ratio, especially to low-sulfur or high-sulfur adaptability, but The carrier used in the catalyst is MgO-TiO 2 -Al 2 o 3 Ternary carrier, during use, MgO and Al 2 o 3 Will transform into magnesium aluminum spinel MgAl 2 o 4 , causing changes in the structure of the catalyst, leading to loss of strength and shortened lifetime

After catalyst calcination, water or steam treatment is required to make MgO and Al 2 o 3 Transformed into a magnesium aluminum spinel structure, resulting in a relatively complicated preparation process, and the low temperature activity of the catalyst needs to be improved

[0007] Chinese patent CN1228139C discloses an alkali metal-containing Co-Mo-K based sulfur-resistant shift catalyst, γ-Al modified with rare earth and zirconium 2 o 3 As a carrier to slow down the decay of catalyst activity and increase the catalytic reaction rate, but the activity at low temperature is insufficient, and it is only suitable for CO shift reaction under the condition of low pressure and low water vapor ratio

The catalyst is not only characterized by high porosity and macroporous structure, but also has good mechanical strength, but it can only be used in the pressure range of 1-3.0MPa, and there are obvious shortcomings in low-temperature activity

Images