CN105618161A

CN105618161A - Method for activating and regenerating catalyst for dehydrogenizing CO raw gas

Info

Publication number: CN105618161A
Application number: CN201610027798.8A
Authority: CN
Inventors: 姚元根; 乔路阳; 周张锋; 宗珊珊
Original assignee: Fujian Institute of Research on the Structure of Matter of CAS
Current assignee: Fujian Institute of Research on the Structure of Matter of CAS
Priority date: 2016-01-16
Filing date: 2016-01-16
Publication date: 2016-06-01
Anticipated expiration: 2036-01-16
Also published as: CN105618161B

Abstract

The invention provides a method for activating and regenerating a catalyst for dehydrogenizing CO raw gas. The method mainly comprises the following steps: performing oxidation and reforming on the catalyst to remove carbon deposition on the surface of the catalyst; performing acid treatment to remove a Fe impurity seeping into the surface of the catalyst; and finally, performing oxidation and chlorination treatment to redisperse precious metal particles gathering on the surface of the catalyst. After treatment of the method, on the surface of the catalyst, the carbon deposition is almost completely removed, the Fe impurity is reduced to 0.04-0.09%, and the precious metal active components are redispersed, so that the catalyst is regenerated and activated and the performance of the catalyst recovers basically. The method has the characteristics of strong pertinence, low cost and simplicity in operation, can guarantee good reproductivity of the catalyst and improve the utilization rate of precious metal greatly, and thus the production cost of industrial batched catalysts is controlled.

Description

A kind of CO unstripped gas catalyst for dehydrogen activating and regenerating method

Technical field

The present invention relates to a kind of activation of catalyst regeneration method, for the activating and regenerating method of the catalyst that the CO unstripped gas dehydrogenating technology in coal-ethylene glycol technology uses.

Background technology

Through the important technology that CO synthesis of oxalate and carbonic ester are C-1 chemistry fields. First coal obtained being mainly composed of CO and H by this technology path by Water gas shift/WGS₂Synthesis gas, secondly separated for this synthesis gas and purification are obtained high-purity CO unstripped gas, finally by CO unstripped gas by catalytic reaction synthesis of oxalate or carbonic ester. The purification of its CO unstripped gas is primarily referred to as H₂Impurity is reduced to below 100ppm, to ensure being normally carried out of subsequent technique. The dehydrogenation that the method for selective oxidation disclosed in patent CN102583374A realizes CO unstripped gas is generally used to purify. The disclosed a kind of effective catalyst of patent CN104162443A in the process can stable operation 4600 hours, this catalyst is using precious metals pd as active component, and using chlorine as auxiliary agent, wherein Pd mass fraction accounts for the 0.1��1% of catalyst gross mass. This catalyst in reaction medium long-time use after, owing to the become estranged performance of these catalyst of reason such as Fe contaminating impurity of Pd species agglomeration, area carbon, chlorine species flow is decreased obviously.

Owing to noble metal reserves are rare and expensive, causing that the preparation cost of noble metal catalyst is higher, the activating and regenerating process of catalyst is subject to the extensive concern of researcher. Patent 101056705 discloses the acid treatment renovation process of a kind of Pt/C catalyst preparing oxyammonia salt; Patent 1201405 discloses the low pressure H of a kind of Ru catalyst being applied to hydrogenation reaction₂The activation method processed; Patent 101024184 discloses the activation method that a kind of alkali being applied to hydrorefined Pd/C catalyst processes. At present, this chlorine used for CO unstripped gas dehydrogenating technology is done the activating and regenerating work of the precious metals pd catalyst of auxiliary agent and is still in blank. If the activity and selectivity part of catalyst can be made to recover by the method for a series of activating and regeneratings, thus realizing the efficient recycling of noble metal catalyst, then the cost of whole process route will be substantially reduced. Commercial production is had important positive effect.

Summary of the invention

It is an object of the invention to provide a kind of CO unstripped gas catalyst for dehydrogen activating and regenerating method, it is achieved chlorine does the efficient recycling in CO unstripped gas dehydrogenating technology of the precious metals pd catalyst of auxiliary agent.

CO unstripped gas catalyst for dehydrogen activating and regenerating method provided by the invention, it specifically comprises the following steps that

A. carbon remover: at the temperature of 450��550 DEG C, passes into H to beds with the speed of 0.3��0.5ml/min₂O steam, passes into O with the speed of 5��20ml/min simultaneously₂, continue 5��10 hours; By online gas chromatogram to CO and CO in tail gas₂Content detect, to monitor the degree of carbon remover, as CO and CO₂Total content lower than 10ppm time can stop de-carbon. When, after catalysqt deactivation, this step can carry out on original production device.

B. except Fe impurity: the catalyst after processing of step A is taken out from reaction unit, puts into the hydrochloric acid that concentration is 0.5��2M, soak 1��3 hour in 30��50 DEG C, leach residual liquid and be neutrality with deionized water wash catalyst to cleaning mixture.

C. chlorine, noble metal redispersion are mended: the catalyst after being processed by step B soaks 0.5��1 hour at the hydrochloric acid solution that concentration is 0.2��1M, makes catalyst pre-acidified; Add, to catalyst injection, the oxidant that volume is equal with total duct volume of catalyst again, make catalyst infiltrate 0.5-1 hour; By catalyst vacuum drying, then microwave treatment 10 minutes in the microwave environment that output is 2-3 kilowatt, with fixing active component; Again by catalyst soak 2-3 hour in deionized water, after filtration, secondary vacuum dries, the catalyst after being regenerated.

It is, with syringe, oxidant is slowly added dropwise by syringe needle catalyst surface moistening catalyst that described injection adds;

Described oxidant is concentration is sodium hypochlorite or the calcium hypochlorite of 0.3��0.8M, or the potassium permanganate that concentration is 2��3M.

For proving the effectiveness of the method, the catalyst before and after regeneration has been carried out a series of sign by us. The obvious redispersion of Pd, the avtive spot reunited in catalyst after finding regeneration by transmission electron microscope in Fig. 1 increase. Finding that the adsorbance of probe CO molecule is substantially increased by regenerated catalyst by CO chemisorbed in Fig. 2, in table 2, visible Pd dispersion rises to 38��52.2% from 8.5%, close to the 54.1% of fresh catalyst; Pd particle size drops to 2.1��3.1nm from 13.2nm, close to the 2.1nm of fresh catalyst. CO is not captured after finding regenerated catalyst oxidation by Fig. 3 Program heating and oxidation and mass spectrometry₂Or the signal peak of CO, illustrate that carbon distribution removes completely. The Fe mass fraction found in regenerated catalyst by plasma emission spectrum test in table 1 is reduced to 0.04��0.09% from 1.73%, illustrates that Fe impurity is substantially achieved elimination; The change of Pd mass fraction is little, illustrates that in regenerative process, active component is substantially free of loss.

Beneficial effects of the present invention shows: by the carbon distribution on a series of chemical means Removal of catalyst surfaces and Fe impurity, supplement run off chlorine species, make noble metal active component again be disperseed, thus realizing the regeneration activating of catalyst and catalytic performance can being made substantially to be recovered. The method is with strong points, catalyst favorable reproducibility, with low cost and simple to operate, greatly improve the utilization rate of noble metal, make the production cost of industrial high-volume catalyst be controlled.

Accompanying drawing explanation

Fig. 1 executes the transmission electron microscope photo that in example 1, catalyst regeneration is forward and backward, and (a) is before regeneration; B () is for after regeneration.

Fig. 2 executes the forward and backward attached adsorption curve inhaled for CO chemistry of catalyst regeneration in example 1, and (a) is the adsorption curve before regeneration; B () is the adsorption curve after regeneration.

Fig. 3 executes the forward and backward temperature programmed oxidation of catalyst regeneration in example 1 and mass spectrometry schematic diagram, and (a) is for before regeneration; B () is for after regeneration.

Detailed description of the invention

Embodiment 1:

(1) pending for 50g Catalyst packing is entered the flat-temperature zone of fixed bed reactors, under inert gas shielding, is warming up to 520 DEG C. H is passed into the speed of 0.5ml/min₂O steam treated 2 hours, passes into O with the speed of 10ml/min₂, keep 6 hours. By online gas chromatogram to H in tail gas₂, CO and CO₂Content detect, to monitor the degree of de-carbon.

(2) being taken out from reaction tube and be placed in beaker by the catalyst after processing, adding 60ml concentration is the hydrochloric acid solution of 1M, in 50 DEG C of process 2 hours, leaches residual liquid and is 6 with the pH value of deionized water wash catalyst to cleaning mixture.

(3) catalyst after step (2) being processed adds hydrochloric acid solution pre-acidified that 60ml concentration is 0.1M process 0.5 hour in beaker, elimination residual night; It is the liquor natrii hypochloritis of 0.5M that injection adds 25ml concentration, infiltration catalyst 0.5 hour; By catalyst vacuum drying 1 hour, microwave treatment 10 minutes under the output of 3 kilowatts; Taking 500ml deionized water and soak catalyst about 3 hours, period changes water 5 times, and after filtration, secondary vacuum dries 12 hours, the catalyst after being regenerated. Analyze result in Table 1 and table 2.

Catalyst after Regeneration Treatment takes 10g be packed in fixed bed reactors and be evaluated experiment. Pass into H₂Temperature programming is reduced 1 hour to 150 DEG C. Each lead into pending CO unstripped gas and O₂, the unstripped gas passed into consists of CO and accounts for 98.4%, H₂Account for 1.6%, the O of addition₂With H₂Volume ratio be 2, total air speed is 10000h^-1, reaction temperature is 180 DEG C, and bed layer pressure is 0.3Mpa. With H in online gas chromatographic detection tail gas₂And O₂Content, and calculate obtain H₂Selectivity. Catalyst performance data is in Table 3.

Embodiment 2:

With preparation process and the appreciation condition of embodiment 1, it is different in that the oxidant of step (3) be concentration is the calcium hypochlorite of 0.8M. Catalyst performance data is in Table 3.

Embodiment 3:

With preparation process and the appreciation condition of embodiment 1, it is different in that the oxidant of step (3) be concentration is the potassium permanganate of 3M. Catalyst performance data is in Table 3.

Embodiment 4:

With preparation process and the appreciation condition of embodiment 1, being different in that the concentration of hydrochloric acid of step (2) is 2M, the process time is 10 minutes. Catalyst performance data is in Table 3.

Embodiment 5:

With preparation process and the appreciation condition of embodiment 1, it is different in that the pre-acidified of step (3) processes the hydrochloric acid solution using 2M, processes 5 minutes. Catalyst performance data is in Table 3.

Comparative example 1:

Take fresh catalyst 10g to react, with the appreciation condition of embodiment 1. Catalyst performance data is in Table 3.

Comparative example 2:

Take successive reaction 4600 hours and part inactivation catalyst 10g react, with the appreciation condition of embodiment 1. Catalyst performance data is in Table 3.

Table 1: the Fe in catalyst and precious metals pd content before and after the regeneration that plasma emission spectrum records

Catalyst condition	Fe mass fraction (%)	Pd mass fraction (%)
			Raw catelyst	0	1.11
Catalyst after inactivation	1.73	0.98
			Catalyst after embodiment 1 process	0.06	0.95
Catalyst after embodiment 2 process	0.09	1.12
			Catalyst after embodiment 3 process	0.06	1.01
Catalyst after embodiment 4 process	0.04	0.92
			Catalyst after embodiment 5 process	0.05	0.98

Table 2: the noble metal dispersion degree in catalyst and particle size before and after the regeneration that chemisorbed records

Catalyst condition	Noble metal dispersion degree (%)	Average particle size particle size (nm)
			Raw catelyst	54.1	2.1
Catalyst after inactivation	8.5	(13.2 illustrating that Pd reunites)
			Catalyst after embodiment 1 process	45.7	2.5
Catalyst after embodiment 2 process	40.1	2.6
			Catalyst after embodiment 3 process	49	2.4
Catalyst after embodiment 4 process	52.2	2.1
			Catalyst after embodiment 5 process	38	3.1

Table 3: the performance comparison of catalyst before and after regeneration

Catalyst condition	Catalyst condition	H₂Remaining (ppm)	H₂Selectivity (%)
				Raw catelyst	Fresh	10	80.3
Catalyst after inactivation	After inactivation	4070	62.9
				Catalyst after embodiment 1 process	Embodiment 1	91	74.2
Catalyst after embodiment 2 process	Embodiment 2	120	66.7
				Catalyst after embodiment 3 process	Embodiment 3	70	66
Catalyst after embodiment 4 process	Embodiment 4	45	68
				Catalyst after embodiment 5 process	Embodiment 5	493	59.1

Claims

1. a CO unstripped gas catalyst for dehydrogen activating and regenerating method, specifically comprises the following steps that

A. carbon remover: at the temperature of 450��550 DEG C, passes into H to beds with the speed of 0.3��0.5ml/min₂O steam, passes into O with the speed of 5��20ml/min simultaneously₂, continue 5��10 hours; By CO and CO in online gas chromatographic detection tail gas₂Content, as CO and CO₂Total content lower than 10ppm time stop de-carbon; When, after catalysqt deactivation, this step carries out on original production device;

B. except Fe impurity: the catalyst after processing of step A is taken out from reaction unit, puts into the hydrochloric acid that concentration is 0.5��2M, soak 1��3 hour in 30��50 DEG C, leach residual liquid and be neutrality with deionized water wash catalyst to cleaning mixture;

C. chlorine, noble metal redispersion are mended: the catalyst after being processed by step B soaks 0.5��1 hour at the hydrochloric acid solution that concentration is 0.2��1M, makes catalyst pre-acidified; Add, to catalyst injection, the oxidant that volume is equal with total duct volume of catalyst again, make catalyst infiltrate 0.5-1 hour; By catalyst vacuum drying, then microwave treatment 10 minutes in the microwave environment that output is 2-3 kilowatt, with fixing active component; Again by catalyst soak 2-3 hour in deionized water, after filtration, secondary vacuum dries, the catalyst after being regenerated;

2. CO unstripped gas catalyst for dehydrogen activating and regenerating method according to claim 1, is characterized in that the chlorine that the method CO unstripped gas dehydrogenating technology suitable in coal-ethylene glycol technology uses makes the precious metals pd catalyst of auxiliary agent.