Composite molybdenum-based catalyst and preparation method and application thereof

A technology of composite molybdenum and catalyst, which is applied in the fields of energy and chemical industry, can solve the problems of complex catalyst composition, cumbersome preparation steps, poor repeatability, etc., and achieve the effect of stable phase structure, overcoming cumbersome preparation process and easy control of conditions

Inactive Publication Date: 2015-03-11
NINGXIA UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] There are many reports on Fe-based catalysts in patents and literature. Although Fe-based catalysts have good catalytic activity and olefin selectivity for CO hydrogenation, their product distribution is broad and there are high by-product CH 4 , CO 2 and C 5 + , severely restricting the development of this technical route
Moreover, the catalysts reported in the literature and patents have complex compositions, cumbersome preparation steps, and poor reproducibility

Method used

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  • Composite molybdenum-based catalyst and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Step 1: Reduction-Carbonization

[0036] Weigh a certain amount of ammonium molybdate (NH 4 ) 6 Mo 7 o 24 4H 2 O, roasted at 450°C for 4h, then weighed 10g of the above-mentioned roasted sample, put it into a quartz tube, placed it in a tube furnace, and controlled it by temperature programming, with CH 4 / H 2 As the carbonization medium, the reduction-carbonization process is carried out, and the specific process is as follows:

[0037] First, at N 2 Under atmospheric conditions (20mL / min), rise from room temperature to 450°C at 5°C / min; then, switch to CH 4 / H 2 Atmosphere (50mL / min), continue to heat up to 700°C at 1°C / min and keep for 4h; then, cool to room temperature; finally, switch to N 2 / O 2 Atmosphere (8mL / min), passivation for 5h, to obtain sample A. in N 2 / O 2 In, O 2 The content is 1v%.

[0038] Step 2: Wet Dipping

[0039] Weigh a certain amount of sample A, according to the molar ratio Mo:K=10:1, equal volume impregnation K 2 CO 3 , dr...

Embodiment 2

[0051] Step 1: Reduction-Carbonization

[0052] Weigh a certain amount of ammonium molybdate (NH 4 ) 6 Mo 7 o 24 4H 2 O, roasted at 500°C for 4 hours, then weighed 10 g of the above-mentioned roasted sample and put it into a quartz tube, placed it in a tube furnace, and controlled it by temperature programming, with CH 4 / H 2 As the carbonization medium, the reduction-carbonization process is carried out, and the specific process is as follows:

[0053] First, at N 2 Under atmospheric conditions (20mL / min), rise from room temperature to 450°C at 5°C / min; then, switch to CH 4 / H 2 Atmosphere (60mL / min), continue to heat up to 700°C at 1°C / min and keep for 5h; then, cool to room temperature; finally, switch to N 2 / O 2 Atmosphere (15mL / min), passivation for 10h, to obtain sample B. in N 2 / O 2 atmosphere, O 2 The content is 0.5v%.

[0054] Step 2: Wet Dipping

[0055] Weigh a certain amount of sample B, according to the molar ratio Mo:K=5:1, impregnate KNO 3 , d...

Embodiment 3

[0066] Step 1: Reduction-Carbonization

[0067] Weigh a certain amount of ammonium molybdate (NH 4 ) 6 Mo 7 o 24 4H 2 O, roasted at 600°C for 2 hours, then weighed 10 g of the sample obtained from the above roasting, put it into a quartz tube, placed it in a tube furnace, and controlled it by temperature programming, with CH 4 / H 2 As the carbonization medium, the reduction-carbonization process is carried out, and the specific process is as follows:

[0068] First, at N 2 Under atmospheric conditions (20mL / min), rise from room temperature to 450°C at 5°C / min; then, switch to CH 4 / H 2 Atmosphere (50mL / min), continue to heat up to 675°C at 1°C / min and keep for 5h; then, cool to room temperature; finally, switch to N 2 / O 2 Atmosphere (15mL / min), passivation for 5h, to obtain sample A. in N 2 / O 2 In, O 2 The content is 1v%.

[0069] Step 2: Wet Dipping

[0070] Weigh a certain amount of sample A, according to the molar ratio Mo:K=20:1, equal volume impregnation...

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Abstract

The invention discloses a composite molybdenum-based catalyst. The composite molybdenum-based catalyst consists of an active component Mo and an auxiliary agent K, wherein molar percentages are as follows: 66.7-96.8% of Mo and 3.2-33.3% of K; Mo exists in a composite form of any two or three phases of a metallic state, oxide and carbide. The invention further discloses a preparation method of the composite molybdenum-based catalyst. The preparation method comprises the following steps: firstly, raising the temperature by using a controlled program to reduce and carbonize MoO3 powder; secondly, impregnating by a wet impregnation method; finally, grinding, tabletting and granulating the powder. The composite molybdenum-based catalyst has the benefits as follows: during CO hydrogenation reaction, the composite molybdenum-based catalyst has high catalytic activity and olefin selectivity, the CO single-pass conversion rate being higher than 80% and the olefin-paraffin ratio (O/P) being higher than 4.0, a product mainly comprises light hydrocarbons (C1-C5), C2-C4 olefins account for more than 49% of the total hydrocarbon content and the C5+ selectivity is lower than 15%; before and after the CO hydrogenation reaction, composite molybdenum-based catalyst is stable in phase structure and is suitable for long-term operation. The preparation method of the composite molybdenum-based catalyst is simple in preparation process and easy to control conditions and has relatively high repeatability.

Description

technical field [0001] The invention relates to a catalyst and its preparation method and application, in particular to a composite molybdenum-based catalyst and its preparation method and application, and belongs to the technical fields of energy and chemical industry. Background technique [0002] Low carbon olefins (C 2 ＝ ~C 4 ＝ ) is an important basic organic chemical raw material, mainly derived from the catalytic cracking of naphtha, alkyl dehydrogenation and methanol to olefins (MTO) and other processes. With the increasing demand for low-carbon olefins, the rising price of petroleum resources and the increasing environmental pressure, it is of great strategic significance to develop a clean, low-energy, low-cost and simple process route for the preparation of low-carbon olefins. [0003] In recent years, the one-step process of preparing light olefins from syngas has attracted much attention. Syngas comes from a wide variety of sources, including coal, natural g...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/78B01J27/22C07C1/06C07C11/02
Inventor 张建利陆世鹏赵天生范素兵
Owner NINGXIA UNIVERSITY
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