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Method for stepwise activating dehydrogenation catalyst by using gas mixture of hydrocarbon/hydrogen and CO-containing gas

A dehydrogenation catalyst and mixed gas technology, which is applied in the field of reduction and activation of C3~C5 alkane dehydrogenation to olefin catalysts, can solve the problem of small surface area of ​​elemental Pt, low catalyst activity and selectivity, and increase the migration ability of metal atoms or metal compounds, etc. question

Active Publication Date: 2013-02-06
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Reduction can make the active components of the catalyst into a single metal state, and can also ensure the dispersion of metal component particles. However, constant temperature and rapid reduction at higher temperatures will easily cause the sintering of metal particles, making the reduced catalyst metal particles larger. As a result, the surface area of ​​exposed elemental Pt is relatively small, which ultimately makes the activity and selectivity of the catalyst lower
Water or OH produced by reduction with pure hydrogen - Increase the mobility of metal atoms or metal compounds, which can easily lead to the aggregation of catalyst active metals
CN200410096308.7 Under the condition of temperature of 240-550°C, the molecular sieve and the noble metal catalyst are contacted with the mixed gas of hydrogen and ammonia for 5-30 hours. While reducing, the strong acid center in the molecular sieve is shielded. This method does not Suitable for the reduction process of low-carbon hydrocarbon dehydrogenation catalysts

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0019] Preparation of Sn-containing alumina support. After mixing a certain amount of 0.98M aluminum trichloride solution and 0.01M tin tetrachloride solution, add an appropriate amount of ammonia water with a mass concentration of 8%, mix evenly in a neutralization tank at 60~80°C, and control the pH value 7.0~9.0, filter, wash with water, acidify, pressurize into balls in the oil ammonia column, dry, age, and roast at 650~750°C for 4 hours to get alumina pellets containing 0.3wt% Sn.

[0020]The alumina pellet carrier containing 0.3% Sn was calcined at 800°C for 3h, the calcined carrier was impregnated with an aqueous solution containing chloroplatinic acid for 6h at 70°C, dried at 120°C for 2h, and calcined at 500°C for 4h. Then activate in air containing water vapor for 4h. Then at 70 °C with KNO 3 Soaked in aqueous solution for 2h, dried and roasted under the same conditions. The loading of each component in the catalyst is: Pt 0.5wt%, Sn 0.3wt%, K 0.5wt%.

[0021] R...

example 2

[0030] The preparation of catalyst is the same as example 1.

[0031] Restoration condition: first Program temperature reduction within the range of 350~450 °C, the heating rate is 1 °C / min, CH in the reducing gas hydrocarbon / hydrogen mixture 4 Accounting for 10% of the volume of the mixed gas; then at a constant temperature of 450°C, the mixed gas of CO and nitrogen is used as the reducing gas, CO accounts for 20% of the volume of the mixed gas, and nitrogen is used as the diluent gas. Constant temperature reduction for 40min. The volumetric space velocity of the reducing gas during the reduction process is 800h -1 .

[0032] Vulcanization conditions : The mass flow rate of the mixed gas of hydrogen sulfide, hydrogen and nitrogen is 900h -1 , the molar ratio is 1:9:5, the temperature is 450°C, and the vulcanization time is 40min.

[0033] Evaluation conditions : The volumetric space velocity of the mixed gas feed is 2000 h -1 , the reaction pressure is 0.1MPa, the r...

example 3

[0035] The preparation of catalyst is the same as example 1.

[0036] Restoration condition: first Program temperature reduction within the range of 400~450 °C, the heating rate is 1 °C / min, CH in the reducing gas hydrocarbon / hydrogen mixture 4 Accounting for 40% of the volume of the mixed gas; then at a constant temperature of 450°C, the mixed gas of CO and nitrogen is used as the reducing gas, CO accounts for 50% of the volume of the mixed gas, and nitrogen is used as the diluent gas. Constant temperature reduction for 30min. The volumetric space velocity of the reducing gas during the reduction process is 2000h -1 .

[0037] Vulcanization conditions : The mass flow rate of the mixed gas of hydrogen sulfide, hydrogen and nitrogen is 900h -1 , the molar ratio is 1:9:5, the temperature is 450°C, and the vulcanization time is 40min.

[0038] Evaluation conditions : The volumetric space velocity of the mixed gas feed is 2000 h -1 , the reaction pressure is 0.1MPa, the ...

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Abstract

The present invention discloses a method for stepwise activating a dehydrogenation catalyst by using a gas mixture of hydrocarbon / hydrogen and a CO-containing gas. The dehydrogenation catalyst is a platinum group metal-supported catalyst. The reductive activation of the dehydrogenation catalyst is performed before use. The reductive activation process includes: first a reductive activation procedure is performed by using the gas mixture of hydrocarbon / hydrogen as the reducing gas, and then a reductive activation procedure is performed by using the CO-containing gas as the reducing gas. The reductive activation temperature is 300-600 DEG C, the total reductive activation time is 0.5-5.0 hours, the time that using the gas mixture of hydrocarbon / hydrogen as the reducing gas accounts for 20%-80% of the total reductive activation time, and the volume hourly space velocity of the reducing gas during the reductive activation is 500-5000h<-1>. Compared with the prior art, the method of the present invention further improves the stability of the dehydrogenation catalyst for light alkanes.

Description

technical field [0001] The invention relates to a reduction and activation method for a low-carbon alkane dehydrogenation to olefins catalyst, in particular to a reduction and activation method for a C3-C5 alkane dehydrogenation to olefins catalyst. Background technique [0002] Since the beginning of the new century, the world's demand for petrochemical raw materials and petrochemical products will continue to grow, and the demand for propylene and butene, which are the basic petrochemical raw materials, will continue to grow. However, the production capacity of conventional steam cracking and FCC technology cannot meet the rapidly growing demand, making it There is a global shortage in the market. Moreover, with the increasing scarcity of petroleum resources, the production of propylene has changed from purely relying on petroleum as a raw material to diversifying the technical route of raw material sources, especially the technical route of producing olefins from low-carb...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/62B01J37/16B01J37/18B01J37/20C07C5/333C07C11/06
CPCY02P20/52
Inventor 李江红张海娟张喜文宋喜军孙潇磊王振宇
Owner CHINA PETROLEUM & CHEM CORP