CN105800614A - Method for removing hydrogen gas impurity in CO feed gas in segmented manner - Google Patents

Abstract

The invention provides a method for removing hydrogen gas impurity in CO feed gas in a segmented manner. The method comprises the following steps: respectively filling three Pd/Al2O3 catalyst with Pd loading capacities being 0.1-0.5%, 0.5-1.5% and 1.5-2% into a catalyst bed layer I, a catalyst bed layer II and a catalyst bed layer III of a tubular fixed bed reactor; introducing to-be-treated feed gas and O2 from the bed layer I, and enabling the to-be-treated feed gas and O2 to sequentially pass through the bed layer II and the bed layer III; separately regulating the temperature of catalyst in each bed layer, so that H2 concentration is reduced to be 20-0 ppm through III-section dehydrogenation. The method adopts segmented gradient filling, so that the using efficiency of the catalyst is improved on the premise of not increasing the dosage of noble metal Pd; the process steps are simple and effective, the purpose is clear, the dehydrogenation efficiency of the noble metal Pd is brought into play to the greatest extent, meaningless consumption of CO is reduced, the selection of catalyst on H2 is improved while the H2 conversion rate is taken into consideration. The method is mainly used for dehydrogenation purifying of CO feed gas for synthesizing oxalate or carbonic ester.

Description

The method of hydrogen impurity in a kind of segmentation elimination CO unstripped gas

Technical field

The invention belongs to industrial application.It is specifically related to a kind of suitable in tubular fixed-bed reactor, CO unstripped gas segmentation dehydrogenation purification process, this process can be applicable in the de-hydrogen purification process of the CO unstripped gas based on the oxalate that CO is start material or carbonates organic compound, the de-hydrogen purification process being specifically for use in coal-ethylene glycol technology oxo process CO unstripped gas.

Background technology

Coal-ethylene glycol is the important technology that C-1 chemistry field is emerging.The CO unstripped gas that carbonylic synthesis technology in this technology uses generally is reformed by fossil resources such as coals and is obtained.But, after the physical means such as pressure-variable adsorption or deep cooling separates, CO unstripped gas still contains a small amount of H₂Impurity, its content can reach 5%.These H₂Impurity can make the catalyst of oxo process face hydrogen inactivation, it is therefore desirable to the H in deep removal CO₂Impurity is to below 100ppm.

At present, the method for selective oxidation is generally used to remove H in the de-hydrogen purification process of coal-ethylene glycol technique₂Impurity.Chinese patent CN104162443A, CN102302938A, CN102583374A disclosure of that shows, this reaction generally carries out in tubular fixed-bed reactor, piles up with certain altitude and be seated in reaction bed after uniformly being diluted by catalyst inert substance.The dehydrogenation used is generally with Al₂O₃Deng metal-oxide as carrier, using the precious metals pd of dead load amount as active component.Up to now, great majority research all concentrates on and finds on novel effective catalyst by the trial various preparation factors of change, for instance Chinese patent CN102284286A uses sol-gal process to prepare Pd/Al₂O₃Dehydrogenation；Chinese patent CN105080538A uses hydrotalcite intercalation method to prepare PdMgAl-LDO/Al₂O₃Dehydrogenation.

But, by Optimizing Technical, improve the service efficiency of original catalyst and can also improve the catalytic effect of reality.H in dehydrogenation reaction process, in pending CO unstripped gas₂Concentration is the highest when coming into contact with catalyst layer, minimum when leaving catalyst layer, presents gradient and reduce in whole beds, and the concentration of CO is stepped up simultaneously.In one-part form dehydrogenating technology, due to H₂The skewness of concentration so that identical and filling even the catalyst of load capacity can not play its effectiveness to greatest extent.At high H₂Concentration district, the Pd load capacity of catalyst is too low, it is necessary to improve reaction temperature, otherwise dehydrogenation poor effect；At low H₂Concentration district, the load capacity of catalyst is too high, the consumption CO that under high temperature, dehydrogenation can be too much, causes that selectivity declines.If can according to H₂The variation tendency of concentration, will have the Catalyst packing of certain negative carrying capacity at specific H₂Concentration ranges, sets suitable reaction temperature respectively, the H in segmentation elimination CO unstripped gas₂Impurity, then the dehydrogenation efficiency of catalyst will be greatly improved.

Summary of the invention

It is an object of the invention to provide H in a kind of segmentation elimination CO unstripped gas₂The method of impurity, the method is mainly used in the dehydrogenation of synthesis of oxalate or carbonic ester CO unstripped gas and purifies.

H in segmentation of the present invention elimination CO unstripped gas₂The method of impurity, is according to H₂Concentration variation tendency in whole beds, is divided into high, medium and low three concentration ranges by beds, and each interval different catalyst of load capacity that loads is to realize segmentation dehydrogenation.

H in segmentation elimination CO unstripped gas₂The method of impurity, specifically comprises the following steps that

A. respectively by Pd/Al₂O₃-1、Pd/Al₂O₃-2 and Pd/Al₂O₃-3 three kinds of catalyst inert substances dilute in proportion；Wherein catalyst Pd/Al₂O₃-1 with the dilution of inert substance 1～5:1 by volume, catalyst Pd/Al₂O₃-2 with the dilution proportion of inert substance 0.3～1:1 by volume, catalyst Pd/Al₂O₃-3 with the dilution proportion of inert substance 0.2～0.5:1 by volume；Described inert substance be quartz sand, porcelain ring, inert alumina or glass pellet one of them.

B. successively by the Pd/Al after processing of step A₂O₃-1、Pd/Al₂O₃-2 and Pd/Al₂O₃-3 catalyst are packed in I, II, III section beds of tubular fixed-bed reactor respectively.

C. by pending unstripped gas and O₂Pass into from bed I, pass sequentially through bed II, bed III；In unstripped gas the content of CO be 95～99.9%, H₂Content be 0.1～5%；The O added₂With H₂Volume ratio be 2:1；Reaction velocity is 1000～10000h^-1；Bed layer pressure is 0.2～0.4Mpa；Heating each bed inner catalyst, wherein I section bed is heated to 160～200 DEG C, and II section bed is heated to 120～160 DEG C, and III section bed is heated to 80～140 DEG C, is directly used in the carbonylic synthesis technology of next stage from III section bed acceptable gas out.

The exhaust sampling respectively each bed exported, and on-line checking and analysis is carried out by gas chromatogram, result shows, after I section dehydrogenation, and H₂Concentration is approximately in 8000～below 3000ppm；After II section dehydrogenation, H₂Concentration is approximately in 2000～below 500ppm；After III section dehydrogenation, H₂Concentration is approximately in 20～0ppm.

Catalyst described in step A is with γ type Al₂O₃For carrier, with Pd for active component, prepared by tradition infusion process, catalyst Pd/Al₂O₃In-1, Pd content is 0.1～0.5%, Pd/Al₂O₃In-2, Pd content is 0.5～1.5%, Pd/Al₂O₃In-3, Pd content is 1.5～2%；Described Pd content is the percent that palladium accounts for catalyst gross mass.

This technique is applicable to single tube or calandria type fixed bed reactor, the de-hydrogen purification process being specifically for use in coal-ethylene glycol technology oxo process CO unstripped gas.

Beneficial effects of the present invention shows: be different from one-part form dehydrogenation, H in the process laminating certain embodiments of segmentation dehydrogenation₂The variation tendency of concentration, under not increasing the premise of consumption of precious metals pd, improves the service efficiency of catalyst；Processing step is simply effective, with strong points；At utmost play the dehydrogenation efficiency of precious metals pd, decreased the unnecessary consumption to CO, take into account H₂Catalyst is improve to H while conversion ratio₂Selectivity.

Accompanying drawing explanation

Fig. 1 is that CO unstripped gas stagewise dehydrogenation purifies schematic diagram

Detailed description of the invention

Embodiment 1:

Adopt the catalyst Pd/Al that weight/mass percentage composition is 0.5%, 1%, 1.5% that infusion process prepares Pd respectively₂O₃-1、Pd/Al₂O₃-2、Pd/Al₂O₃-3。

Before filling, the α type Al selecting diameter to be 2mm₂O₃Bead dilute catalyst, by 5gPd/Al₂O₃-1 and Al₂O₃Bead 1:1 by volume dilutes, by 10gPd/Al₂O₃-2 and Al₂O₃Bead 0.5:1 by volume dilutes, by 5gPd/Al₂O₃-3 and Al₂O₃Bead 0.3:1 by volume dilutes；

Successively by the Pd/Al after processing of step A₂O₃-1、Pd/Al₂O₃-2 and Pd/Al₂O₃-3 catalyst are packed in I, II, III section beds of tubular fixed-bed reactor respectively；Pd/Al₂O₃-3、Pd/Al₂O₃-2 and Pd/Al₂O₃-1 these three catalyst is packed in tubular fixed-bed reactor I, II, III section beds respectively；Pass into pending unstripped gas and O to bed simultaneously₂, in unstripped gas the content of CO be 98.5%, H₂Content be 1.5%, the O of addition₂With H₂Volume ratio be 2:1, reaction velocity is 10000h^-1, bed layer pressure is 0.25Mpa.After passing into gas, the temperature of three sections of beds is separately heated to: I section bed 160 DEG C, II section bed 140 DEG C, III section bed 120 DEG C.After reaching reaction temperature, each section of reaction end gas being sampled, and is carried out on-line checking and analysis by gas chromatogram, result is in Table 1.

Embodiment 2:

Catalyst is prepared, wherein Pd/Al with embodiment 1₂O₃In-1, the mass percent of Pd is 0.3%, Pd/Al₂O₃In-2, the mass percent of Pd is 1%, Pd/Al₂O₃In-3, the mass percent of Pd is 1.7%.According still further to 5gPd/Al₂O₃-1 dilutes with dispersant 2:1 by volume, 10gPd/Al₂O₃-2 dilute with dispersant 0.5:1 by volume, 5gPd/Al₂O₃-3 dilute with dispersant 0.25:1 by volume；

According to the experiment condition of the stagewise dehydrogenation of embodiment 1, being different in that the heating-up temperature of three sections of beds, be I section bed 180 DEG C respectively, II section bed 150 DEG C, III section bed 100 DEG C, evaluating catalyst result is in Table 1.

Embodiment 3:

With embodiment 1, it is different in that 8gPd/Al₂O₃-1 dilutes with dispersant 1:1 by volume, 4gPd/Al₂O₃-2 dilute with dispersant 0.5:1 by volume, 8gPd/Al₂O₃-3 dilute with dispersant 0.3:1 by volume, and evaluating catalyst result is in Table 1.

Embodiment 4:

With the preparation method of embodiment 1, it is different in that and prepares Pd/Al₂O₃In-1, the mass percent of Pd is 0.1%, Pd/Al₂O₃In-2, the mass percent of Pd is 1%, Pd/Al₂O₃In-3, the mass percent of Pd is 1.9%.With the appreciation condition of embodiment 1, it is different in that dilution mode, specifically takes 5gPd/Al₂O₃-1 dilutes with dispersant 5:1 by volume, takes 10gPd/Al₂O₃-2 dilute with dispersant 0.5:1 by volume, take 5gPd/Al₂O₃-3 dilute with dispersant 0.2:1 by volume；Alsoing differ in that the heating-up temperature of three sections of beds, respectively: I section bed 180 DEG C, II section bed 150 DEG C, III section bed 100 DEG C, evaluating catalyst result is in Table 1.

Comparative example 1:(and one-part form compare)

The Pd/Al that weight/mass percentage composition is 1% of Pd is prepared according to the method identical with embodiment 1₂O₃Catalyst,

Weigh 20g catalyst and the α type Al that diameter is 2mm₂O₃Bead 1:3 by volume uniformly dilutes, and piles up the beds being packed into tubular fixed-bed reactor；Carry out dehydrogenation evaluation, pass into pending unstripped gas and O to bed simultaneously₂, in unstripped gas the content of CO be 98.5%, H₂Content be 1.5%, the O of addition₂With H₂Volume ratio be 2:1, reaction velocity is 10000h^-1, bed layer pressure is 0.25Mpa, and the heating-up temperature of catalyst entirety bed is 160 DEG C；After reaching reaction temperature, reaction end gas being sampled, and is carried out on-line checking and analysis by gas chromatogram, evaluation result is in Table 1.

Comparative example 2:

With preparation method and the appreciation condition of comparative example 1, being different in that bed heating-up temperature is 180 DEG C, evaluating catalyst result is in Table 1.

Comparative example 3:

With preparation method and the appreciation condition of comparative example 1, being different in that bed heating-up temperature is 200 DEG C, evaluating catalyst result is in Table 1.

Table 1: embodiment 1～4 and evaluating catalyst result in comparative example 1～3

Claims (3)

1. H in a segmentation elimination CO unstripped gas₂The method of impurity, specifically comprises the following steps that

A. respectively by Pd/Al₂O₃-1、Pd/Al₂O₃-2 and Pd/Al₂O₃The catalyst of-3 three kinds of different palladium content and inert substance dilute in proportion；Wherein catalyst Pd/Al₂O₃-1 with the dilution of inert substance 1～5:1 by volume, catalyst Pd/Al₂O₃-2 with the dilution proportion of inert substance 0.3～1:1 by volume, catalyst Pd/Al₂O₃-3 with the dilution proportion of inert substance 0.2～0.5:1 by volume；Described inert substance is one of them of quartz sand, porcelain ring, inert alumina or glass pellet；

B. successively by the Pd/Al after processing of step A₂O₃-1、Pd/Al₂O₃-2 and Pd/Al₂O₃-3 catalyst are packed in I, II, III section beds of tubular fixed-bed reactor respectively；

C. by pending unstripped gas and O₂Pass into from bed I, pass sequentially through bed II, bed III；In unstripped gas the content of CO be 95～99.9%, H₂Content be 0.1～5%；The O added₂With H₂Volume ratio be 2:1；Reaction velocity is 1000～10000h^-1；Bed layer pressure is 0.2～0.4Mpa；Heating each bed inner catalyst, I section bed is heated to 160～200 DEG C, and II section bed is heated to 120～160 DEG C, and III section bed is heated to 80～140 DEG C, is directly used in the carbonylic synthesis technology of next stage from III section bed acceptable gas out.

Catalyst described in step A is with γ type Al₂O₃For carrier, with Pd for active component, prepared by tradition infusion process, catalyst Pd/Al₂O₃In-1, Pd content is 0.1～0.5%, Pd/Al₂O₃In-2, Pd content is 0.5～1.5%, Pd/Al₂O₃In-3, Pd content is 1.5～2%；Described Pd content is the percent that palladium accounts for catalyst gross mass.

2. H in segmentation according to claim 1 elimination CO unstripped gas₂The method of impurity, is characterized in that the method is suitable for single tube or calandria type fixed bed reactor, the de-hydrogen purification process being specifically for use in coal-ethylene glycol technology oxo process CO unstripped gas.

3. H in segmentation according to claim 1 elimination CO unstripped gas₂The method of impurity, is characterized in that the method is after I section dehydrogenation, H₂Concentration reduces to 8000～3000ppm；After II section dehydrogenation, H₂Concentration reduces to 2000～500ppm；After III section dehydrogenation, H₂Concentration reduces to 20～0ppm.