A sulfur-tolerant shift catalyst, its preparation method and application
By loading CoO and MoO3 onto an acid-modified attapulgite-bismuth titanate composite support, a one-dimensional porous-layered active phase structure is formed, which solves the problems of high cost and insufficient stability of cobalt-molybdenum based catalysts. This results in a low-cost, high-activity, and high-stability sulfur-resistant shift catalyst suitable for the coal chemical industry.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QINGDAO ZHONGCHENG SHENGKE BIOLOGICAL CO LTD
- Filing Date
- 2026-03-28
- Publication Date
- 2026-05-29
AI Technical Summary
Existing cobalt-molybdenum based sulfur-resistant shift catalysts are costly, have poor dispersion of active components, and lack stability, leading to easy pulverization and activity decay under high space velocity conditions.
CoO and MoO3 were loaded onto an acid-modified attapulgite-bismuth titanate composite support to form a one-dimensional channel-layered active phase structure. The dispersion of the active components was improved through electronic coupling. Furthermore, chelating dispersants and additives were used to form a Co-Mo-O composite active phase, thereby enhancing the stability and activity of the catalyst.
A low-cost, highly active, and highly stable sulfur-resistant shift catalyst has been developed, which can maintain a high CO conversion rate under high space velocity conditions, extend catalyst life, and is suitable for efficient and stable operation in the coal chemical industry.
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Abstract
Description
Technical Field
[0001] This application relates to the field of catalyst technology, specifically to a sulfur-resistant shift catalyst, its preparation method, and its application. Background Technology
[0002] Sulfur-resistant shift catalysts are core catalytic materials in the coal chemical industry, mainly used to catalytically convert CO and water vapor in coal gasification products into CO2 and hydrogen, achieving the purpose of hydrogen production or adjusting the CO / H2 ratio in the reaction gas. Among them, cobalt-molybdenum-based catalysts have been widely used in China due to their excellent sulfur resistance, wide reaction temperature range, and absence of polluting chromium.
[0003] Existing cobalt-molybdenum based sulfur-resistant shift catalysts typically use relatively expensive industrial raw materials such as Al and Si as supports, resulting in high catalyst preparation costs. In addition, in the existing preparation processes of sulfur-resistant shift catalysts, the active components cobalt and molybdenum are mostly supported by stepwise impregnation or simple co-impregnation methods, resulting in uneven dispersion of the two on the support surface. This easily leads to the formation of isolated regions rich in cobalt or molybdenum, which prevents the full realization of the electronic modification effect of cobalt on molybdenum. This directly affects the activity and stability of the catalyst, and problems such as pulverization and rapid activity decay are prone to occur under high space velocity conditions.
[0004] Therefore, developing a low-cost, highly dispersible, and highly stable sulfur-resistant shift catalyst is of great significance to the coal chemical industry. Summary of the Invention
[0005] To overcome the problems of high cost, poor dispersion of active components, and insufficient stability of existing sulfur-resistant shift catalysts, this application provides a sulfur-resistant shift catalyst, its preparation method, and its application.
[0006] In a first aspect, this application provides a sulfur-resistant shift catalyst, which adopts the following technical solution: A sulfur-resistant shift catalyst comprises the following components in parts by weight: a support, an active component, and an additive; The support is an acid-modified attapulgite-bismuth titanate composite support; the active components are CoO and MoO3, which are loaded in the catalyst at 2-5 wt% and 8-12 wt%, respectively.
[0007] This application uses an acid-modified attapulgite-bismuth titanate composite as a support, with specific loadings of CoO and MoO3 as active components, to form a synergistically optimized system. This effectively solves the problems of high raw material cost, poor dispersion of active components, and insufficient stability in traditional cobalt-molybdenum-based sulfur-resistant shift catalysts. Specifically, the support used in this application uses low-cost natural attapulgite as the matrix. Layered perovskite titanate with a specific structure is generated in situ on the surface of the modified attapulgite using a sol-gel method, thus forming a one-dimensional pore-layered active phase composite support structure. This results in a composite support with high specific surface area, strong synergistic effect, and low cost. The structure of this support provides uniform loading sites for CoO and MoO3, and also efficiently collects or traps impurities such as dust and tar in the process gas, avoiding activity decay caused by pore blockage. Furthermore, the Bi content of bismuth titanate... 3+ With Ti 4+ It can form electronic coupling with the active components, effectively preventing Co and Mo from agglomerating on the support surface to form cobalt-rich or molybdenum-rich isolated regions. This promotes full contact between the two to form a Co-Mo-O composite active phase, significantly improving the dispersion and synergistic efficiency of the active components, resulting in a significant increase in the initial CO conversion rate of the catalyst under high space velocity conditions. In summary, the sulfur-resistant shift catalyst provided in this application combines low cost, high activity, and strong stability, making it suitable for harsh conditions of high space velocity and high impurities, and providing reliable support for the efficient, stable, and economical operation of shift systems in the coal chemical industry.
[0008] Optionally, the preparation method of the acid-modified attapulgite-bismuth titanate composite support includes the following steps: preparing acid-modified attapulgite, preparing bismuth titanate precursor solution, and composite and calcination activation; The concentration of the hydrochloric acid solution used in the step of preparing acid-modified attapulgite is 3-10 wt%. The calcination activation is carried out according to the following heating program: the temperature is increased from 20-35℃ to T1260-350℃ at a heating rate of 4-6℃ / min (V1), and held for t11-1.5h; then the temperature is increased to T2500-600℃ at a heating rate of 2-3.5℃ / min (V2), and held for t23-5h.
[0009] In some embodiments, the concentration of the hydrochloric acid solution may be 3-5 wt%, 3-8 wt%, 3-10 wt%, 5-8 wt%, 5-10 wt%, or 8-10 wt%.
[0010] In one specific implementation, the concentration of the hydrochloric acid solution may also be 3wt%, 5wt%, 8wt%, or 10wt%.
[0011] In some embodiments, the heating rate V1 can be 4-5°C / min or 4-6°C / min.
[0012] In one specific implementation, the heating rate V1 can also be 4℃ / min, 5℃ / min or 6℃ / min.
[0013] In some implementations, the temperature T1 can be 260-300°C or 300-350°C.
[0014] In one specific implementation, the temperature T1 can also be 260°C, 300°C, or 350°C.
[0015] In one specific implementation, the heat preservation time t1 can also be 1 hour or 1.5 hours.
[0016] In some embodiments, the heating rate V2 can be 2-3℃ / min or 3-3.5℃ / min.
[0017] In one specific implementation, the heating rate V2 can also be 2℃ / min, 3℃ / min or 3.5℃ / min.
[0018] In some implementations, the temperature T2 can be 500-550°C or 550-600°C.
[0019] In one specific implementation, the temperature T2 can also be 500°C, 550°C, or 600°C.
[0020] In some implementations, the heat preservation time t2 can also be 3-4 hours or 4-5 hours.
[0021] In one specific implementation, the heat preservation time t2 can also be 3h, 4h or 5h.
[0022] Optionally, the additive is a mixture of K2O and La2O3 or Ce2O3.
[0023] Optionally, the loading of K2O in the catalyst is 1-2 wt%, and the loading of La2O3 or Ce2O3 in the catalyst is 1-3 wt%. Optionally, the sulfur-resistant conversion catalyst further includes a chelating dispersant selected from citric acid and ethylenediaminetetraacetic acid.
[0024] Optionally, a binder needs to be added in the compounding and calcination activation steps. The binder is selected from one or more of guar gum powder, hydroxymethyl cellulose, high clay, alumina sol and silica sol.
[0025] Secondly, this application provides a method for preparing a sulfur-resistant shift catalyst, comprising the following steps: Cobalt salt and molybdenum salt are dissolved in water, and then other components except the support are added and stirred evenly to obtain an impregnation solution. The support is impregnated in the impregnation solution for 4-6 hours, and then dried and calcined to obtain a sulfur-resistant conversion catalyst.
[0026] Optionally, the drying temperature is 90-120℃; the calcination temperature is 500-550℃, and the time is 3-4 hours.
[0027] Thirdly, this application provides an application of a sulfur-resistant shift catalyst in ammonia synthesis and hydrogen production processes.
[0028] In summary, this application has the following beneficial effects: This application uses an acid-modified attapulgite-bismuth titanate composite as a support. By loading active components CoO and MoO3, a low-cost, high-activity, and stable sulfur-resistant shift catalyst can be obtained. When used in the process of catalytic conversion of CO and water vapor to CO2 and hydrogen, the CO conversion rate can still reach more than 80% after 2000 hours of continuous operation, and the activity decay rate is less than 3%. Detailed Implementation
[0029] This application provides a sulfur-resistant shift catalyst, comprising the following components in parts by weight: a support, an active component, a chelating dispersant, and an auxiliary agent; the support is an acid-modified attapulgite-bismuth titanate composite support; the active component is CoO and MoO3, with loadings of 2-5 wt% and 8-12 wt% respectively in the catalyst; the chelating dispersant is selected from citric acid and ethylenediaminetetraacetic acid; the auxiliary agent is a mixture of K2O and La2O3 or Ce2O3.
[0030] This application provides an acid-modified attapulgite-bismuth titanate composite support, the preparation method of which includes the following steps: (1) Preparation of acid-modified attapulgite: Natural attapulgite (particle size ≤10μm) is added to a 3-10wt% hydrochloric acid solution at a liquid-solid ratio of 10:1 and stirred and refluxed at 70-90℃ and 300-500r / min for 2-3h. After the reaction is completed, it is cooled and then vacuum filtered and washed with deionized water. The washed filter cake is crushed and dried. Then it is transferred to a muffle furnace and heated to 600-700℃ at 3-8℃ / min and kept warm for calcination and activation for 2-3h. After cooling, ball milling and passing through an 80-mesh sieve, acid-modified attapulgite is obtained.
[0031] (2) Preparation of bismuth titanate precursor solution: Add anhydrous ethanol to bismuth nitrate, stir at 200-300 r / min for 20-30 min, filter to obtain a transparent bismuth nitrate ethanol solution; slowly add tetrabutyl titanate to the above bismuth nitrate solution at a dropping rate of 3-5 mL / min, while increasing the stirring rate to 400-500 r / min; after the dropping is completed, add glacial acetic acid, continue stirring for 1-1.5 h, add an appropriate amount of water, adjust the solid content to 20-25 wt%, and obtain a light yellow transparent bismuth titanate precursor solution; In bismuth nitrate and tetrabutyl titanate, the molar ratio of Bi to Ti is 2:1.
[0032] (3) Composite and calcination activation: The acid-modified attapulgite obtained in step (1) is added to the bismuth titanate precursor solution obtained in step (2), stirred and kneaded at 60-70℃ for 2-3h, aged at 20-30℃ for 10-14h, and pre-dried at 80-100℃ for 4-6h; then a binder is added to the dried material, mixed evenly, an appropriate amount of water is added, the solid content is adjusted to 20-25wt%, stirred and kneaded again for 20-30min, and then extruded and calcined to obtain an acid-modified attapulgite-bismuth titanate composite carrier with a particle size of 2-3mm; The calcination process is carried out according to the following heating procedure: the temperature is increased from 20-35℃ to T1260-350℃ at a heating rate of 4-6℃ / min (V1), and held for t11-1.5h; then the temperature is increased to T2500-600℃ at a heating rate of 2-3.5℃ / min (V2), and held for t23-5h.
[0033] This application provides a method for preparing a sulfur-resistant shift catalyst, comprising the following steps: dissolving cobalt salt and molybdenum salt in water, then adding other components except for the support, stirring evenly to obtain an impregnation solution; impregnating the support in the impregnation solution for 4-6 hours, then drying and calcining to obtain the sulfur-resistant shift catalyst; the drying temperature is 90-120℃; the calcination temperature is 500-550℃, and the time is 3-4 hours.
[0034] The raw materials, reagents, solvents, etc. used in this application can all be obtained commercially.
[0035] The following describes this application in further detail with reference to preparation examples, embodiments, and performance testing. Preparation Example 1
[0036] Preparation Example 1 provides an acid-modified attapulgite-bismuth titanate composite carrier.
[0037] The preparation method of the above-mentioned acid-modified attapulgite-bismuth titanate composite support includes the following steps: (1) Preparation of acid-modified attapulgite: 1000g of natural attapulgite (particle size ≤10μm) was added to a 5wt% hydrochloric acid solution at a liquid-to-solid ratio of 10:1 and stirred and refluxed at 80℃ and 400r / min for 2h. After the reaction was completed, the mixture was cooled and then vacuum filtered and washed with deionized water. The washed filter cake was crushed to a particle size ≤5mm and dried at 120℃ for 12h. Then it was transferred to a muffle furnace and heated to 650℃ at 5℃ / min and calcined for 2h. After cooling, ball milling and passing through an 80-mesh sieve, acid-modified attapulgite was obtained.
[0038] (2) Preparation of bismuth titanate precursor solution: Add 500 mL of anhydrous ethanol to 280 g of bismuth nitrate, stir at 200 r / min for 30 min, filter to obtain a transparent bismuth nitrate ethanol solution; slowly add 100 g of tetrabutyl titanate to the above bismuth nitrate solution at a dropping rate of 5 mL / min, while increasing the stirring rate to 400 r / min; after the dropping is completed, add 50 g of glacial acetic acid, continue stirring for 1 h, add an appropriate amount of water, adjust the solid content to 25 wt%, and obtain a light yellow transparent bismuth titanate precursor solution.
[0039] (3) Composite and calcination activation: The acid-modified attapulgite obtained in step (1) is added to the bismuth titanate precursor solution obtained in step (2), stirred and kneaded at 65°C for 2 hours, aged at 25°C for 12 hours, and pre-dried at 100°C for 5 hours. Then, based on the material, 5wt% of guar gum powder is added to the dried material, mixed evenly, and an appropriate amount of water is added to adjust the solid content to 25wt%. The mixture is stirred and kneaded again for 30 minutes, and after extrusion molding and calcination, an acid-modified attapulgite-bismuth titanate composite carrier with a particle size of 2-3 mm is obtained. The calcination process is carried out according to the following heating procedure: the temperature is increased from 25℃ to T1300℃ at a heating rate of 5℃ / min (V1), and held for t11h; then the temperature is increased to T2550℃ at a heating rate of 3℃ / min (V2), and held for t24h. Preparation Example 2
[0040] Preparation Example 2 provides an acid-modified attapulgite-bismuth titanate composite carrier.
[0041] The difference between the above preparation example and preparation example 1 is that the concentration of hydrochloric acid solution in step (1) is 3 wt%. Preparation Example 3
[0042] Preparation Example 3 provides an acid-modified attapulgite-bismuth titanate composite carrier.
[0043] The difference between the above preparation example and preparation example 1 is that the concentration of hydrochloric acid solution in step (1) is 8 wt%. Preparation Example 4
[0044] Preparation Example 4 provides an acid-modified attapulgite-bismuth titanate composite carrier.
[0045] The difference between the above preparation example and preparation example 1 is that the concentration of hydrochloric acid solution in step (1) is 10 wt%. Preparation Examples 5-8
[0046] Preparation Examples 5-8 provide an acid-modified attapulgite-bismuth titanate composite carrier.
[0047] The difference between the above preparation example and preparation example 1 is that: (3) In the compounding and calcination activation steps, the calcination temperature rise procedure is as shown in Table 1 below.
[0048] Table 1. Temperature program for calcination in the composite and calcination activation steps of Preparation Examples 1 and 5-8. Examples 1-8
[0049] Examples 1-8 each provide a sulfur-resistant shift catalyst.
[0050] The difference between the above embodiments is that the acid-modified attapulgite-bismuth titanate composite carriers used in Examples 1-8 were respectively derived from Preparation Examples 1-8.
[0051] The preparation method of the sulfur-resistant shift catalyst provided in Examples 1-8 includes the following steps: (1) 12.4g Co(NO3)2・6H2O (CoO loading is 3wt%) and 34.8g (NH4)6Mo7O 24 • 4H2O (MoO3 loading of 10wt%) was dissolved in water, and then 2.5g KNO3 (K2O loading of 1.5wt%) and 7.5g La(NO3)3・6H2O (La2O3 loading of 2wt%) were added and stirred evenly to obtain the impregnation solution; (2) Take 100g of acid-modified attapulgite-bismuth titanate composite carrier and impregnate it in the above impregnation solution for 5h, then dry it at 100℃ for 4h, and then put the shaped material into a muffle furnace and calcine it at 550℃ for 3h to obtain sulfur-resistant conversion catalyst. Example 9
[0052] Example 9 provides a sulfur-resistant conversion catalyst.
[0053] The difference between the above embodiment and Embodiment 1 is that 7.5g La(NO3)3・6H2O (La2O3 loading 2wt%) is replaced with 5.3g Ce(NO3)3・6H2O (Ce2O3 loading 2wt%). Example 10
[0054] Example 10 provides a sulfur-resistant shift catalyst.
[0055] The difference between the above embodiment and embodiment 1 is that 6.4g of citric acid is added to the impregnation solution in step (1). Comparative Example 1
[0056] Comparative Example 1 provides a sulfur-resistant shift catalyst.
[0057] The difference between the above comparative example and Example 1 is that the acid-modified attapulgite-bismuth titanate composite support is replaced with γ-Al2O3 (specific surface area 220m2 / g). The preparation method of the above-mentioned sulfur-resistant shift catalyst is as follows: 34.8g (NH4)6Mo7O 24 • 4H2O (MoO3 loading of 10wt%) was dissolved in 100mL of water and stirred evenly to obtain a molybdenum salt impregnation solution; 12.4g Co(NO3)2・6H2O (CoO loading of 3wt%), 2.5g KNO3 (K2O loading of 1.5wt%), and 7.5g La(NO3)3・6H2O (La2O3 loading of 2wt%) were dissolved in 100mL of water and stirred evenly to obtain a cobalt salt impregnation solution; 100g of γ-Al2O3 was first impregnated in a molybdenum salt impregnation solution for 2h, dried at 120℃ for 2h, and calcined at 550℃ for 2h; then it was impregnated in a cobalt salt impregnation solution for 2h, dried at 120℃ for 2h, and calcined at 550℃ for 3h to obtain a sulfur-resistant conversion catalyst. Performance testing
[0058] The catalysts from Examples 1-10 and Comparative Example 1 were respectively loaded into a fixed-bed reactor and the catalytic reaction was carried out under the following conditions: temperature 280°C, pressure 3.0 MPa, and gas hourly space velocity 6000 h⁻¹. -1 The feed gas composition (volume fraction) was: CO 15%, H2S 0.5%, H2O 30%, N2 4.5%. The CO conversion rate was measured before and after 2000 hours of continuous operation, and the activity decay rate was calculated. The results are shown in Table 2 below.
[0059] Table 2. Evaluation results of the catalyst effects in Examples 1-10 and Comparative Example 1
[0060] According to the test results in Table 2, the sulfur-resistant shift catalysts obtained in Examples 1-10 showed an initial CO conversion rate of 83.6-87.5%, a CO conversion rate of 81.4-86.8% after 2000 hours, and an activity decay rate of 0.80-2.91%. In contrast, the sulfur-resistant shift catalyst obtained in Comparative Example 1 showed an initial CO conversion rate of 86.3%, a CO conversion rate of only 75.6% after 2000 hours, and an activity decay rate as high as 12.40%. Therefore, this application demonstrates that the sulfur-resistant shift catalyst obtained by using an acid-modified attapulgite-bismuth titanate composite as a support and loading active components CoO and MoO3 has advantages such as low cost, high activity, and good stability. It can withstand harsh reaction conditions with high space velocities and high impurities, providing reliable support for the efficient, stable, and economical operation of shift systems in the coal chemical industry.
[0061] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.
Claims
1. A sulfur-resistant shift catalyst, characterized in that, It comprises the following components in parts by weight: carrier, active ingredient, and additives; The support is an acid-modified attapulgite-bismuth titanate composite support; the active components are CoO and MoO3, which are loaded in the catalyst at 2-5 wt% and 8-12 wt%, respectively.
2. The sulfur-resistant shift catalyst according to claim 1, characterized in that, The preparation method of the acid-modified attapulgite-bismuth titanate composite carrier includes the following steps: preparing acid-modified attapulgite, preparing bismuth titanate precursor solution, composite and calcination activation. The concentration of the hydrochloric acid solution used in the step of preparing acid-modified attapulgite is 3-10 wt%. The calcination activation is carried out according to the following heating program: the temperature is increased from 20-35℃ to T1260-350℃ at a heating rate of 4-6℃ / min (V1), and held for t11-1.5h; then the temperature is increased to T2500-600℃ at a heating rate of 2-3.5℃ / min (V2), and held for t23-5h.
3. The sulfur-resistant shift catalyst according to claim 1, characterized in that, The additive is a mixture of K2O and La2O3 or Ce2O3.
4. The sulfur-resistant shift catalyst according to claim 3, characterized in that, The loading of K2O in the catalyst is 1-2 wt%, and the loading of La2O3 or Ce2O3 in the catalyst is 1-3 wt%.
5. The sulfur-resistant shift catalyst according to claim 1, characterized in that, The sulfur-resistant conversion catalyst also contains a chelating dispersant selected from citric acid and ethylenediaminetetraacetic acid.
6. The sulfur-resistant shift catalyst according to claim 2, characterized in that, The composite and calcination activation steps require the addition of an adhesive, which is selected from one or more of guar gum powder, hydroxymethyl cellulose, high clay, alumina sol, and silica sol.
7. The method for preparing the sulfur-resistant shift catalyst according to any one of claims 1-6, characterized in that, Includes the following steps: Cobalt salt and molybdenum salt are dissolved in water, and then other components except the support are added and stirred evenly to obtain an impregnation solution. The support is impregnated in the impregnation solution for 4-6 hours, and then dried and calcined to obtain a sulfur-resistant conversion catalyst.
8. The method for preparing the sulfur-resistant shift catalyst according to claim 7, characterized in that, The drying temperature is 90-120℃; the calcination temperature is 500-550℃, and the time is 3-4 hours.
9. The application of a sulfur-resistant shift catalyst as described in any one of claims 1-6 in ammonia synthesis and hydrogen production processes.