CN1205114C - Method for preparing carbon mono oxide trasform catalyst without potassium - Google Patents

Abstract

The present invention relates to a preparation method of a catalyst for carbon monoxide conversion reaction. When the catalytic weight is used as references, the catalyst has the chemical constitution of 7 to 10% of MoO3, 1.0 to 3.5% of CoO and Mg-Al-O spinelle carriers as the rest, wherein the Mg-Al-O spinelle carrier is prepared by that multiporous unformed aluminum oxide with 45% to 70% of water content, and light MgO are mixed and kneaded, and then are squeezed for forming to be dried and calcined. Mg-Al-O spinelle prepared by unformed aluminum oxide is used as a carrier; Mg-Al-O forms a perfect spinelle structure, so the catalyst activity is enhanced; the catalyst of the present invention can be used in wider pressure range (the pressure is larger than or equal to 1.5MPa) and wider steam-gas ratio which is larger than or equal to 0.3; the CO conversion rate reaches as high as 92%.

Description

The preparation method of potassic carbon monoxide transformation catalyst not

(1) technical field

The present invention relates to a kind of carbon monodixe conversion catalysts and preparation method thereof.

(2) background technology

So-called carbon monodixe conversion reaction refers to carbon monoxide (CO) and water vapour (H ₂O) reaction generates hydrogen (H ₂) and carbonic acid gas (CO ₂), it is to produce the hydrogen necessary procedure by coal or hydrocarbonaceous mineral.Carbon monodixe conversion only just has considerable speed of reaction under catalyst, so the catalytic performance of catalyzer has great effect to the economic benefit of production process.Carbon monoxide transformation catalyst can be divided into three major types.The one, the Cu-Zn class, this type of catalyzer low temperature (180～250 ℃) is active high, but easy loss of activity and easily being poisoned by the sulphur in the unstripped gas (S) under the high temperature, life cycle is short.The 2nd, the Fe-Cr class, the performance of this type of catalyzer opposing sulfur poisoning is better than the Cu-Zn class, but only under higher temperature (400～450 ℃) considerable activity is arranged.The 3rd, the Co-Mo class, its manufacturing cost of this type of catalyzer is higher, but its advantage is that (170～450 ℃) all have higher activity in very wide temperature range, and be difficult for being poisoned by sulphur.So recent years, the 3rd class catalyzer has obtained using widely, has replaced preceding two class catalyzer gradually, and its development also is very active.

U.S. Pat 3957962, US4166101 has reported with γ-Al ₂O ₃For the Co-Mo of carrier is a transformation catalyst.Subsequently, find to add basic metal (as K, Na etc.) element and can improve this type of activity of such catalysts, corresponding patent has U.S.3850840, U.S.3957962 and Chinese patent CN 87107892 etc.What developed the alkali-free metal afterwards again is the Co-Mo catalyzer (U.S.4153580 and Chinese patent 96100935.7) of carrier with the Mg-Al spinel.The catalyzer of alkali metal containing is applicable to the operating conditions of low reaction pressure (≤2.0 MPa) and low steam-gas ratio (mol ratio of water vapour and other gas is≤0.3 in the reactor feed gas), and is that the Co-Mo series catalysts of carrier is applicable to high-response pressure (3.0～10MPa) and the operating conditions of high steam-to-gas ratio (～1.8) with the Mg-Al-O spinel.Not potassic Co-Mo/Mg-Al-O class catalyzer is closely related for the catalytic activity and the Mg-Al-O crystalline phase of CO transformationreation, and when Mg-Al-O presented comparatively perfect spinel structure, catalyzer had higher activity.But this type of catalyzer must be made bigger particulate state (diameter is greater than 3mm during sphere, and diameter is greater than 2.5mm during strip) in industry is used, and the particle shape of loaded catalyst is determined by its carrier.There are some difficulties in present technology when preparation particulate state Mg-Al-O spinel.When preparing with coprecipitation method, the factor that influences the finished product character is more, and quality product is unstable, and this method preparation process is more, and preparation cycle is long.When preparing with blending method, its advantage is that preparation technology is simple, and quality product is controlled easily.But if be difficult for forming complete Mg-Al-O spinel when adopting conventional raw material pseudo-boehmite and lightweight MgO to carry out blend to prepare.

(3) summary of the invention

The object of the present invention is to provide a kind of Mg-Al-O spinel with unformed aluminum oxide preparation is carrier, can the broad pressure range (〉=1.5MPa) and broad steam-to-gas ratio (〉=0.3) use down, have the preparation method of the not potassic carbon monoxide Co-Mo transformation catalyst of higher catalytic activity.

The chemical constitution of the said catalyzer of the present invention is (is benchmark with the catalyst weight) MoO ₃7%～10%; CoO1.0%～3.5%; Surplus is the Mg-Al-O spinel carrier.

The Preparation of catalysts step is as follows:

1) presses lightweight MgO and aluminum oxide (with butt Al ₂O ₃Calculate) mol ratio is to take by weighing lightweight MgO and porousness moisture unformed aluminum oxide at 1: 1, places kneading machine, adds aqueous acid and mixes and pinch pressure, forms plastic; The water content of the moisture unformed aluminum oxide of said porousness is at 45%～70% (weight), and said aqueous acid is nitric acid, formic acid or acetic acid.

2) above-mentioned plastic is placed on the banded extruder push, form strip.

3) above-mentioned strip is dried 4～6h down at 80～150 ℃.

4) with the oven dry strip at 700～900 ℃ of following roasting 2～4h, obtain porousness Mg-Al-O spinel carrier.

5) the strip carrier after the roasting is flooded with the ammonia soln that contains Co salt and Mo salt, said Co salt is selected from Xiao Suangu or Cobaltous diacetate etc., and Mo salt is selected from ammonium molybdate etc.

6) strip that step (5) gained is contained Co salt and Mo salt brine solution dewaters under 120～200 ℃, obtains the porousness solid catalyst.

The present invention is a carrier with the Mg-Al-O spinel of unformed aluminum oxide preparation, and its Mg-Al-O presents comparatively perfect spinel structure, has improved activity of such catalysts.Catalyzer provided by the invention is applicable to the transformationreation of pressure 〉=1.5MPa and vapour gas mol ratio 〉=0.3 time CO.The activity rating of catalyst condition is: reaction pressure 2MPa, gas space velocity 5000h ^-1, 200～400 ℃ of temperature of reaction, unstripped gas is formed (weight percent): CO 30%, CO ₂6%, H ₂59%, N ₂5%, S 50 μ gg ^-1, characterize activity of such catalysts with the CO transformation efficiency.

Catalyzer with carry out prevulcanized before reaction raw materials contacts, the concise and to the point program of prevulcanized is: feed reactor feed gas earlier, volume space velocity is 1000h ^-1, be warming up to 180 ℃ after, inject CS ₂, continue then to heat up, at 350 ℃ and 420 ℃ of following constant temperature sulfuration 2h, slowly be cooled to desired reaction temperature more respectively.

(4) embodiment

Further illustrate the present invention below by embodiment.

Embodiment 1

1) gets 1mol lightweight MgO and contain Al ₂O ₃The unformed aqueous alumina of 1mol (water content is 58%) places small-sized kneading machine to carry out thorough mixing, progressively adds concentration again and be 4% HNO ₃The aqueous solution is pinched pressure.Control HNO ₃The add-on of the aqueous solution makes final material become plastic, extrudes slivering easily.

2) step (1) gained final material is placed extrude slivering on the banded extruder, strip is a right cylinder, diameter 3.5～4.5mm.

3) will be by step (2) gained strip dry 4h under 100 ℃, dry atmosphere is air.

4) strip of oven dry is calcined 3h down at 850 ℃, obtain porousness Mg-Al-O spinel bar shaped carrier.

5) preparation Co-Mo-NH ₃The aqueous solution takes by weighing the Xiao Suangu 60.0g that contains CoO 25.0%, contains MoO ₃82.5% ammonium molybdate 50.9g is 9.0% ammonia soln 160ml dissolving with concentration, adds ammonia soln at last and makes final Co-Mo-NH ₃Aqueous solution volume is 200ml, and is standby.Strength of solution is for containing MoO ₃0.210gml ^-1, contain CoO 0.075gml ^-1

6) use by step (5) gained Co-Mo-NH ₃Solution soaking continues 24h by step (4) gained bar shaped carrier under the room temperature.

7) Co-Mo-NH is contained in the inside in the separating step (6) ₃The bar shaped solids and the surplus solution of solution.

8) with the solids in the step (7) at 180 ℃ of dry 6h, i.e. the final catalyzer of cost example.This routine catalyzer does not need roasting.

The gained catalyzer is formed and activity rating the results are shown in table 1.

Embodiment 2

In embodiment 1 step (5), the Xiao Suangu add-on changes 40.0g into, and the ammonium molybdate add-on changes 54.5g into, and final solution concentration is for containing MoO ₃0.225gml ^-1, contain CoO 0.050gml ^-1All the other operations are constant.This routine gained catalyzer forms and activity rating the results are shown in Table 1.

Embodiment 3

In embodiment 1, use water content in the step (1) instead and be 48% unformed aluminum oxide, i.e. the cost example.This routine gained catalyzer forms and activity rating the results are shown in Table 1.

Embodiment 4

In embodiment 1, use water content in the step (1) instead and be 65% unformed aluminum oxide, i.e. the cost example.This routine gained catalyzer forms and activity rating the results are shown in Table 1.

Embodiment 5

In embodiment 1, change the maturing temperature in the step (4) into 760 ℃, i.e. the cost example.This routine gained catalyzer forms and activity rating the results are shown in Table 1.

Embodiment 6

In embodiment 1, change the temperature for removing water in the step (6) into 140 ℃, i.e. the cost example.This routine gained catalyzer forms and activity rating the results are shown in Table 1.

Comparative example 1

In embodiment 1, use water content in the step (1) instead and be 30% pseudo-boehmite, i.e. the cost example.This routine gained catalyzer forms and activity rating the results are shown in Table 1.

The chemical constitution and the activity rating result of above each the routine catalyzer of table 1

	Form		The activity rating result (the CO transformation efficiency/%)
								MoO 3％	CoO％	200℃	250℃	300℃	350℃	400℃
	Embodiment 1	8.3	3.0	92.1	90.3	88.6	90.5								91.0
Embodiment 2								9.0	2.0	91.6	89.4	87.2	89.8	90.6
	Embodiment 3	8.4	3.1	91.3	89.2	87.0	89.5								89.9
Embodiment 4								8.1	2.9	92.3	90.4	88.8	90.6	91.2
	Embodiment 5	8.3	3.0	91.1	89.2	87.0	89.4								89.8
Embodiment 6								8.2	2.9	92.0	90.1	89.2	90.3	90.9
	Comparative example 1	8.5	3.2	84.5	81.6	78.3	82.3								83.7

Claims (2)

1. the preparation method of potassic carbon monoxide transformation catalyst not is characterized in that said catalyzer is that the chemical constitution of benchmark is MoO with the catalyst weight ₃7%～10%, CoO 1.0%～3.5%, and surplus is the Mg-Al-O spinel carrier; The Preparation of catalysts step is as follows:

1) with butt Al ₂O ₃Calculating, is to take by weighing lightweight MgO and porousness moisture unformed aluminum oxide at 1: 1 by lightweight MgO and alumina molar ratio, places kneading machine, adds aqueous acid and mixes and pinch pressure, formation plastic; Said aqueous acid is a nitric acid, formic acid or acetic acid;

2) plastic is placed on the banded extruder push, form strip;

3) strip is dried 4～6h down at 80～150 ℃;

4) with the oven dry strip at 700～900 ℃ of following roasting 2～4h, obtain porousness Mg-Al-O spinel carrier;

5) the strip carrier after the roasting is flooded with the ammonia soln that contains Co salt and Mo salt, said Co salt is Xiao Suangu or Cobaltous diacetate, and Mo salt is ammonium molybdate;

6) strip that step (5) gained is contained Co salt and Mo salt brine solution dewaters under 120～200 ℃, obtains the porousness solid catalyst.

2. the preparation method of not potassic carbon monoxide transformation catalyst as claimed in claim 1 is characterized in that the moisture unformed aluminum oxide of said porousness water content by weight percentage is 45%～70%.