Acrylic acid catalyst regeneration method

A catalyst and acrylic acid technology, which is applied in the field of catalysis, can solve the problems of frequent shutdown and regeneration, reduction of catalyst activity, expansion of pore distribution, etc., and achieve the effects of prolonging service life, not easy to sinter, and strong anti-coking ability

Inactive Publication Date: 2014-02-05
CHINA NAT OFFSHORE OIL CORP +1
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AI Technical Summary

Problems solved by technology

The production of acrylic acid through the oxidation of acrolein has a higher yield and lower greenhouse gas emissions. At present, 90% of the oxidation devices use this process, but there are two common problems: one is that the oxidation catalyst has a relatively long service life. Big defect, the current published patents (CN1147356C, CN1087658C) claim that acrylic acid catalysts have improved catalyst strength and wear, but these traditional catalysts have been practically used in industrial production for several years, and none of them can be used in terms of catalytic performance stability. It is completely satisfactory; in addition, the reaction space velocity of the catalyst is difficult to increase. Under high load conditions, the temperature of the catalyst bed rises sharply to generate hot spots, and then the active components in the catalyst are sublimated, resulting in a decrease in catalytic activity. Therefore, for the occurrence of The shell-and-tube reactor for the oxidation reaction can only increase the production of acrylic acid by increasing the size of the reactor
However, in the actual production of acrylic acid, hot spots frequently appear in the catalyst bed and transfer irregularly, which brings great difficulties to the actual operation. This may be because the large amount of heat released by the oxidation reaction of acrolein is difficult to quickly remove. Layers are continuously superimposed, resulting in hot spots
In addition, due to the generation of hot spots, the sublimation of active components, especially Mo, reduces the activity of the catalyst, requiring frequent regeneration of the catalyst and reducing the production cycle of the acrylic acid unit
[0006] The salient feature of the spherical catalysts currently used in industry is that the catalyst pores are widely distributed, which is easy to cause carbon deposition, and the active components loaded on the surface of the catalyst are easy to fall off, especially after regeneration treatment, the situation becomes more serious, the pores The distribution is further expanded, and the surface structure characteristics are destroyed. In the later stage of catalyst use, production shutdown and regeneration become more frequent, which seriously affects the production efficiency of the factory.

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0028] Embodiment 1: Preparation and evaluation of fresh catalyst

[0029]First, heat 5L of pure water to 95°C, add 135.5g of ammonium metatungstate to it, then add 151.8g of ammonium metavanadate and 916.7g of ammonium metamolybdate in turn, and dissolve it under stirring to obtain an orange transparent solution Add 1.5L of ethanol after the solution is cooled below 40°C, and stir at high speed to form a uniform solution; then add 64.4g of antimony acetate to the above solution to form a black aqueous dispersion; then, dissolve 129.7g of copper sulfate in 833g of pure water , mixed with the above black dispersion to obtain a slurry, which was refluxed at 95°C for 2 hours; ethanol was added at a rate of 20ml / min, and water in the system was separated by distillation. When it is detected that the ethanol content in the distillate is not less than 95%, the slurry is spray-dried, the nozzle temperature is controlled at 140°C, the feeding speed is adjusted to keep the outlet tempe...

reference example 1

[0039] Reference Example 1: Preparation and Evaluation of Deactivated Catalyst

[0040] Put the fresh catalyst into a stainless steel reaction tube with an inner diameter of 25ml, pass through the raw material gas composed of 6.5% acrolein, 8.5% oxygen, 52% nitrogen, and 33% water vapor in molar percentages, at a pressure of 0.2MPa , the gas volumetric space velocity is 1800hr -1 The oxidation reaction of acrolein was carried out under 6000 hours to obtain a deactivated catalyst, and its pore distribution is shown in Table 1.

[0041] Put 100ml of deactivated catalyst into a stainless steel reaction tube with an inner diameter of 25ml, pass through the raw material gas composed of 6.5% acrolein, 8.5% oxygen, 52% nitrogen, and 33% water vapor in molar percentage. 0.2MPa, gas volume space velocity is 1800hr -1 The acrolein oxidation reaction was carried out at a temperature of 250° C., and the reaction results shown in Table 2 were obtained.

reference example 2

[0042] Reference Example 2: Preparation and Evaluation of Traditional Regenerated Catalyst

[0043] The deactivated catalyst prepared in Reference Example 1 was heated up to 390° C. at a rate of 1° C. / hour, and calcined at this temperature for 1 day to obtain a regenerated catalyst.

[0044] Put 100ml of the regenerated catalyst into a stainless steel reaction tube with an inner diameter of 25ml, pass through the raw material gas composed of 6.5% acrolein, 8.5% oxygen, 52% nitrogen, and 33% water vapor by mole percentage, at a pressure of 0.2 MPa, gas volume space velocity is 1800hr -1 The acrolein oxidation reaction was carried out at a temperature of 250° C., and the reaction results shown in Table 2 were obtained.

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Abstract

The invention relates to an acrylic acid catalyst regeneration method. An acrylic acid catalyst has a concentrated pore distribution and a moderate total pore volume, the amount of medium-sized pores of about 5-10nm accounts for above 70% of the amount of total pores, and the medium-sized pores of about 5-10nm form short and thick tunnel structures, so the catalyst has the characteristics of strong carbon deposit resistance, difficult agglomeration and long service life. The two-step calcining regeneration method for regenerating an inactivated acrylic acid catalyst comprises the following steps: heating the inactivated acrylic acid catalyst to 280-320DEG C at a speed of 1-2DEG C/h, and carrying out constant temperature calcining for 1-10h; and heating to 330-370DEG C at a speed of 1-2DEG C/h, calcining in an oxidizing gas for 1-3d, heating to 380-410DEG C, and calcining in nitrogen atmosphere for 1-3d to obtain a regenerated acrylic acid catalyst having an equivalent activity with the fresh catalyst.

Description

Technical field: [0001] The invention relates to the technical field of catalysis, in particular to a method for regenerating an acrylic acid catalyst with a special pore structure. Background of the invention: [0002] At present, the industrial production of acrylic acid mainly adopts a two-step oxidation method, the first step is the oxidation of propylene to acrolein, and the further oxidation of acrolein to acrylic acid. The production of acrylic acid through the oxidation of acrolein has a higher yield and lower greenhouse gas emissions. At present, 90% of the oxidation devices use this process, but there are two common problems: one is that the oxidation catalyst has a relatively long service life. Big defect, the current published patents (CN1147356C, CN1087658C) claim that acrylic acid catalysts have improved catalyst strength and wear, but these traditional catalysts have been practically used in industrial production for several years, and none of them can be used...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/888B01J23/94C07C51/235C07C57/055
CPCY02P20/584
Inventor 曾贤君于海斌孙彦民李晓云隋云乐苗静李世鹏周鹏杨文建
Owner CHINA NAT OFFSHORE OIL CORP
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