KR820000066B1 - Co, convertion catalyst - Google Patents

Abstract

An Al2O3 supported Co0-Mo03 catalyst is described for conversion of CO2 by reaction with H2O vapor with formation of H and CO2. The catalyst was active in the presence of scompds. The Al2O3 carrier was stabilized by admixt. with rare earth oxides while the Al2O3 was in the hydrated forms. The carrier retained its high surface area and was not converted to α-Al2O3.

Description

Carbon Monoxide Phone Catalyst

A catalyst for converting carbon monoxide in a synthetic cutlet mixture into hydrogen and a cutlet of carbonate, which is active in the presence of a sulfur compound and cobalt and molybdenum supported on a molded, relatively high surface alumina quality carrier. A catalyst based on molybdenum oxide, such as an oxide of, the carrier is stabilized by mixing with one or more rare earth metal oxides while the alumina is in the form of a hydrate, and the mixture of hydrated alumina and rare earth metal oxides is shaped into a desired form. Hydrated alumina is calcined to convert to oxide. The calcined high surface area alumina is then impregnated with the preferred cobalt and molybdenum salts so that the impregnated catalyst can then be calcined and used. The stabilized catalyst exhibits good activity at relatively low temperatures in the synthetic cutlet mixture containing sulfur compounds, maintains its surface area and does not convert the alumina carrier into the alpha phase.

The present invention relates to the production of hydrogen by the reaction of steam and carbon monoxide in the presence of a catalyst. More specifically, the present invention provides a method for producing hydrogen and converting carbon monoxide in a synthetic cutlet mixture, and more particularly, the present invention provides a method for converting carbon monoxide in a synthetic cutlet mixture containing impurities with sulfur to hydrogen and cutlet carbonate. To provide.

The conversion of carbon monoxide has been known for a long time as a method for producing hydrogen and cutlet carbonate. Many catalysts and the like have been proposed for use in carbon monoxide conversion reactions or aqueous cut shift processes. U. S. Patent No. 417,068 discloses that a nickel or metal cobalt phase applied on a refractory, porous material such as pumice stone can be obtained by passing carbon monoxide and steam. Bosch and Wild have proposed in US Pat. No. 1,113,097 to carry a cobalt component on a refractory and porous material. Larson, in 1932, proposed a catalyst of copper and various Group 6 metal oxides in US Pat. No. 1,889,672. U.S. Patent No. 1,797,426 discloses a reduced copper oxide-zinc oxide (CuO-ZnO) catalyst for carbon monoxide conversion reactions used at reaction temperatures of 570 ° F or higher. In industrial examples, however, the use of iron oxide-chromium oxide catalysts at reaction temperatures of 750-850 ° F. or higher, despite the advantage of high carbon monoxide at equilibrium. This process is essentially at low temperature until Edward K. Dienes proposes a low temperature zinc oxide-copper oxide catalyst active at a temperature of 500 ° F. or lower in US Pat. No. 3,303,001. The value of this technology that could be used to complete the call was not fully appreciated.

Unfortunately, this catalyst cannot withstand traces of sulfur in the raw materials. Coal, coke and heavy hydrocarbon feedstocks suitable for conversion to hydrogen contain significant amounts of sulfur in the conversion to hydrogen sulphide and very small amounts of carbon disulfide and carbonyl sulphide, so these feedstocks contain copper-zinc oxide catalysts. It is limited to temperatures up to 950 ° F, using a sulfur-resistant catalyst such as iron oxide promoted by chromium oxide, to prevent its use. There is a recent need to develop sulfur-resistant carbon monoxide conversion catalysts due to the lack of sulfur-free raw materials and the increasing dependence of compounds on feedstocks containing relatively high percentages of sulfur compounds.

Various proposals have been made for oxidation and cobalt sulfide-molybdenum catalysts supported on carriers of relatively high surface areas.

Examples are British Patent 940,960, United States Patent 3,392,001 and United States Patent 3,529,935. Aldridge's guitar is described in U.S. Patent No. 3,850,820 at relatively low temperatures for carbon monoxide conversion in sulfur-containing airflows in place of copper zinc oxide catalysts in the final stages of the multistage inversion process. It is proposed a catalyst that is resistant to active sulfur. Aldridge's others pointed out that the process's equilibrium is largely temperature dependent and that low temperatures shift the conversion of carbon monoxide in the right direction, increasing hydrogen production. As a result, the inverter pointed out that it is possible to increase the temperature and the work and contact temperature of the cutlet from which the carbonic acid is removed. In the third stage, the use of a catalyst that is active in the presence of sulfur at low temperatures essentially completes the process of eliminating costly operation. The supported oxidation and cobalt sulfide-molybdenum catalysts thus replace some of the classical iron oxide-chromium oxide catalysts at least in the later stages of the multistage reactor. This is because these catalysts exhibit higher activity at lower temperatures than iron oxide-chromium oxide catalysts. However, these catalysts tend to lose surface area over long periods of use and to lose physical quality and catalyst strength. It is believed that this high surface area alumina is involved in the transition to the alpha phase due to the loss of significant surface area. This phenomenon is not completely understood because the transition temperature from gamma alumina to alpha alumina is reported to be in the range of 1000-1200 ° C (1832-2192 ° F) by Hindin et al.

The temperature of this process never reaches this high temperature, but the catalyst loses strength and surface area and transitions to the alpha phase. Rare earth metal oxides have been proposed for the stabilization of various high temperature catalysts. For example, British Patent No. 1,398,893 proposes to stabilize the coating of transitional alumina so that rare earth metal oxides supported on honey-comb of a ceramic skeleton have a temperature of 982.2 ° C (1800 ° F). Withstand Mr. Stoles, in U.S. Patent No. 3,645,915, restricts the use of lanthanum-based rare earth metal oxides in stabilizing oxidation steam reforming catalysts for steam hydrocarbon reforming. However, Mr. Steeles coats nickel and chromium nickel mixed with rare earth metal oxides on pellets or particulates of alpha-alumina, and Mr. Hindin uses 1200 ° C (2192 ° F) in US Pat. No. 3,870,455. It has been proposed to prepare a mixed slip of aluminum, Group 6B metals and various other components for coating on a honeycomb core made of ceramics for reaction above temperature.

According to the present invention, high surface area alumina carriers of cobalt and molybdenum components for use at relatively low temperatures in the presence of steam and hydrogen sulfide are stabilized by adding rare earth metal oxides to alumina in the hydrate state. A lanthanum series rare earth metal oxide is added to the hydrated alumina and the mixture is mixed to form a homogeneous mixture, which is then dried into a desired form. By calcination, the hydrated alumina is converted to alumina in the transition stage of the high surface area alumina. The shaped tablets are then impregnated in a conventional manner using appropriate amounts of cobalt and molybdenum salts to make the appropriate catalyst. The catalyst prepared in this way was found to have good activity in the carbon monoxide conversion process at relatively low temperatures, in the presence of sulfur compounds, and in the presence of steam. These catalysts do not lose surface area even after prolonged use under extremely stringent conditions, and the carrier does not change to the alpha phase.

The catalyst prepared according to the process of the present invention can be regenerated and reused by oxidation and resulfurization of the catalyst while charged in the reactor. The sulfidation process can be achieved by passing a process cut containing a sulfur compound on the catalyst.

Preferred embodiments are described below.

As described above, as the feedstock containing no sulfur content is insufficient, there is an increasing need to develop an active catalyst for carbon monoxide conversion in the presence of sulfur compounds. Synthetic cutlet mixtures have become increasingly dependent on sulfur-rich crude oil and / or coal to produce hydrogen. However, such a process requires a catalyst that is so severe that it maintains its surface area, maintains its physical strength, does not shrink and does not cause spalling. It is evident that the conditions are particularly severe at high steam partial pressures in the multistage process.

Under these conditions, many alumina-based catalysts have a tendency to move to the alpha stage, to lose their characteristic blue color, to lose most of the mechanical strength, and to contract in the reactor, causing spalls. This is especially noticeable after regeneration.

Cobalt according to the prior art in suitable process conditions for converting carbon monoxide to hydrogen and carbohydrate. The mechanism by which the gamma alumina of the molybdenum oxide catalyst transfers to alpha alumina is not completely understood. It is known that the transition temperature for gamma alumina to transition to the alpha phase is in the range of 1800-2000 ° F. Process temperatures are well below this range, and molybdenum oxide is known to start moving at temperatures above 1300 ° F.

Therefore, at the high transition temperatures required to convert from gamma to alpha alumina, molybdenum oxide will evaporate completely from the catalyst pellets. Nevertheless, in the X-ray diffraction of the catalyst for the agent, the presence of alpha alumina and unknown crystal phases was observed, but there was no clear loss of molybdenum oxide. Unknown crystalline phases, under process conditions where high steam partial pressures and sulfur compounds are present, the reaction between hydrogen sulfide and molybdenum oxide or hydrogen sulfide and aluminum oxide or aluminum oxide and molybdenum oxide form metal sulfates (as unknown crystalline phases) which are oxidized by reduction It may be suggested to return to aluminum, only another phase (alpha phase) or to promote the conversion of alumina to alpha phase in some way.

Through experiments on the present invention, it became clear that the generation of an unknown phase is accompanied by the conversion of the gamma phase to the alpha phase and loss of surface area and strength of the pellet.

The present inventors do not wish to be limited by this theory, but they believe that the unexplained surface area loss and the crystal phase of the alumina of the catalyst according to the prior art provide a plausible explanation for the conversion at low temperatures.

Broadly described, the transition to the gamma phase by firing, the gamma phase over a long time operation and one or more regeneration operations in the presence of high steam partial pressure and sulfur compounds, to maintain a high surface area accompanying it The use of a catalyst containing a stabilized alumina carrier is also included in the present invention. The carrier is impregnated and refired in a solution of cobalt and molybdenum salts by well known methods after the stabilizing step to convert the salts into oxides. The alumina carrier can be derived by precipitation with or in the presence of an insoluble lanthanide rare earth metal compound. In a preferred method of preparing a carrier, a lanthanum-based rare earth metal compound is mixed with hydrated alumina to form a slurry in which these compounds are well mixed with each other. The mixture is sufficiently dried, the mixture is shaped into the desired shape and the carrier of the shaped catalyst is calcined again and the alumina is converted into one of the transition steps, in particular gamma phase. Throughout the specification and the appended claims, all surface areas were measured by BET or an equivalent method. Catalytically active components, ie cobalt and molybdenum, are present in the filamentous catalyst by impregnation in aqueous salt solutions. As such, the cobalt component can be impregnated on a carrier in an amine carbonate solution or in a nitrate solution, so the cobalt mapping concentration in the finishing catalyst is 2-5% by weight (expressed in metal) of the total catalyst including the carrier. Molybdenum, on the other hand, is usually present in the form of ammonium molybdate in aqueous solution. Thus, the catalyst carrier is deposited thereon until the concentration of molybdenum oxide on the filamentous catalyst (in terms of metal is 10-16% by weight, preferably 13-15% by weight.) One advantage of the cobalt amine impregnated material Is the fact that ammonium molybdate is also soluble in conditions where the material can melt, so that they can be impregnated onto the carrier by simultaneous deposition of these materials, according to the manufacture of this catalyst which involves two firings. It is intended to convert shaped particles of silver alumina and rare earth metal salts into oxides, to stabilize oxides of the oxide into the alumina lattice, and to prevent or substantially reduce the subsequent transition of high surface area alumina oxides to alpha alumina. The temperature range should be 900-1600 ° F. The temperature at the high end of this scale is the gamma alumina to alpha phase transition. Should be avoided because it is likely to occur at temperatures above 1800 ° F. The second firing should be carried out at substantially lower temperatures of 700-1100 ° F. The salts of cobalt and molybdenum are impregnated after impregnation on the stabilized molding carrier. Call it oxide.

Aqueous cutlet shift reactions are well known. According to the invention the total amount of the steep ranges from 0.5 to 100, preferably 1.5-25 volumes, per volume of carbon monoxide. The pressure is preferably 200-1500 pounds / square inch, psig, preferably in the range of 1-200 atmospheres or more. The temperature pressure of the reaction mixture in contact with the process catalyst is kept below the dew point pressure because the temperature is above the dew point temperature of the mixture. This process is particularly effective when the feedstock contains a small amount of sulfur in the form of hydrogen sulfide and organic sulfides. In fact, the presence of small amounts of sulfur in the feedstock actually results in higher conversion rates in many cases. In addition, the catalyst of the present invention can be regenerated by oxidation and resulfurization resulting therefrom.

The use of several lanthanum rare earth metal oxides as a material to be stabilized with an alumina carrier is included in the scope of the present invention. However, lanthanum itself is said to be the most effective. However, endodim, salium or praseodym can be used separately or in combination with other rare earth metal oxides. Commercially available mixtures of lanthanum-rich rare earth metal oxides have been widely used to practice the invention with some robustness. The standard composition of this mixture is as follows.

The rare earth metal oxide used as the carrier is in the range of 0.5-10% by weight (indicated by metal), and is preferably about 3% by weight. The ratio of alumina oxide and rare earth metal oxide, that is, REO: Al ₂ O ₃ should be less than 1: 10, and in the study of the present invention, the ratio of 1: 100 was found to be very suitable.

In all the examples, the impregnation solution was prepared as follows, although not in accordance with the specification. It should be noted that in order to change the final component of the catalyst, the concentration of various components may sometimes be changed. Nevertheless, it was basically formulated as follows. As required amount of ammonium molybdate is added to the required amount of cobalt amine carbonate solution until the desired molybdenum: cobalt ratio in the finishing catalyst is equal to the molybdenum: cobalt ratio in the impregnation solution. The preferred concentration of the catalyst component is governed by the metal concentration of the impregnation solution.

Example 1

25 pounds of hydrated alumina is placed in a mixer with 53 grams of spray dried silicon oxide. Here, 362 grams of nitrate of high lanthanum rare earth is slowly added to a solution dissolved in 30 gallons of water. Mix until the entire mixture is homogeneous. The time was recorded at this time and the homogeneous mixture was dried at 300 ° F. until the burn loss was 25% by weight. The time and burning loss were recorded. The dry material was granulated and mixed with 3% by weight aluminum stearate, the mixture was molded into tablets and calcined at 1250 ° F. These tablets were impregnated in cobalt and molybdenumamine solution, dried sufficiently and refired at 900 ° F. The composition of the finishing catalyst was as shown in the first table.

[Table 1]

Example 2

This catalyst was prepared according to the preparation of Catalyst C in US Pat. No. 3,529,935. Al ₂ (SO _{4) 3} · 18H ₂ O was dissolved, 885 grams and ZnSO ₄ · 4H ₂ O, 650g in 4 liters of water and heated to 90 ℃. The resulting precipitate was filtered by addition of ammonia until the pH was 6.8 and washed with 1% (NH ₄ ) CO ₃ solution until the sulfate disappeared.

The carrier was then mixed with 49 grams of Co (CO ₃ ) ₂ .6H ₂ O and 44 grams of ammonium molybdate, dried at 212 ° F, molded into tablets, and calcined at 1112 ° F. This catalyst has the composition and characteristics described under Sample 2 of the first table.

Example 3

性磁鐵鑛) 2400그램과 베에마이트(Boemite) 8250그램을 건식 혼합한 다음 37.5%의 질산코발트 용액 250ml와 68%의 몰리브덴산 암모늄용액 2,000ml을 가하여 혼합하였다. 혼합물질을 212℉로 건조하고, 과립으로 만들어, 전제성형하였다. 본 촉매의 조성 및 특성은 제1표의 샘플 3에 도시한 바와 같다.This catalyst corresponds to catalyst D of US Pat. No. 3,529,935. Caustic iron (

After dry mixing 2400 grams and 8250 grams of boemite, 250 ml of 37.5% cobalt nitrate solution and 2,000 ml of 68% ammonium molybdate solution were added and mixed. The mixture was dried to 212 ° F., granulated and preformed. The composition and properties of this catalyst are as shown in Sample 3 of the first table.

Example 4

This catalyst was prepared in the same manner as in the catalyst of Example 1 except that the ratio of the rare earth nitrate solution in the carrier composition was slightly improved while the percentage of spray dried silicon oxide was slightly increased. The catalyst carrier was tablet molded and calcined at 1250 ° F. These were then impregnated with the impregnation solution until the concentrations of cobalt oxide and molybdenum oxide as shown in Sample 4 of Table 1 were reached.

Example 5

Sample 5 was manufactured in a commercial factory and contains no rare earth oxide stabilizer or silicon oxide. The composition is a cobalt molybdenum catalyst as shown in Sample 5 of Table 1 and without the use of stabilizers and promoters on activated alumina. Each of these catalysts was subjected to a special steaming test developed to evaluate and distinguish various catalyst preparations. This test involves the adoption of the inlet gas stream concentration shown below.

Composition percent Composition percent

CO 49% H ₂ 49%

H ₂ S 2.0%

This gas mixture was passed through a catalyst bed with a steam to gas ratio of 3: 1 at a temperature of 800 ° F. for 60 hours. The space velocity, defined as the dry reference capacity of the cut through per volume of catalyst unit per hour, was 3,000 and the pressure was 1,000 psig. At the end of 60 hours the temperature was raised from 800 ° F. to 900 ° F. and the test continued for 40 hours under the same conditions except for this high temperature. The catalyst was then burned in air to remove carbon and residues from the catalyst surface, regenerated and tested for activity.

In Table 1, the compressive strengths for the new catalysts of Samples 1 to 5 are substantially the same, and are the dead dead weykt loads in the range of 15 to 22. However, after 60 hours of use, i.e., sample 1, the compressive strength dropped to 12 pounds, and after 100 hours of use, the stabilized catalyst of sample 1 remained 12 pounds while the unpromoted cobalt molybdenum of sample 5 remained. 5.6 pounds for the catalyst. After regeneration, the compressive strength of sample 1 was 11, the compressive strength of sample 2 catalyst C was 16, and the compressive strength of the stabilized catalyst of sample 4 was 13.6. Catalyst 3 of sample 3 was 31.8% compared to 73% of compressive strength retention of sample 1 and 80% of samples 2 and 4. The compressive strength retention was calculated from the formula described at the end of the first table.

Looking at the surface area, it can be seen that the initial surface area is in the range of 127 to 228. However, after 100 hours of use and play a catalyst surface area of the sample 1 was reduced to 101m ² / g from 175m ² / g. However, it should be noted that the surface areas of samples 2 and 3 were reduced to 54.8 and 32.7 m ² / g, respectively. The surface area of the catalyst to stabilize the sample 4 in the surface area of the sample 5 are not stabilized cobalt molybdenum catalyst in respect to being reduced to 97m ² / g should be also noted that reduced to 50m ² / g. Therefore, the surface area retention of stabilized catalysts is superior to US Pat. No. 3,529,935 and unstabilized cobalt molybdenum catalysts. The activity measured by the rate of carbon monoxide leakage after prolonged use of the stabilized catalyst of Sample 1 is clearly equal to or better than other catalysts. However, the extraction diffraction test for the emitter catalyst showed gamma alumina for the stabilized catalysts of samples 1 and 4, the catalysts of unstabilized samples 2 and 5 exhibited alpha alumina, and the unstabilized samples 3 and 5 were destroyed. It is interesting to represent one phase.

Example 6

The carrier material prepared according to Example 1 was deposited in the impregnation solution used in Example 1 until the finishing composition of the catalyst had a composition as shown in Sample 6 of Table 2. The ratio of rare earth oxides to alumina was 1:25.

Example 7

The catalyst of Sample 7 is a commercially run cobalt molybdenum catalyst prepared from a factory containing a catalyst containing 3.22% cobalt oxide, 14.11% molybdenum oxide, and the remaining gamma alumina.

Since most of the problems with this catalyst are thought to occur in commercial units with high splitting of the steep found in multistage carbon monoxide conversion systems, the catalyst of Sample 6 was subjected to a long life test compared to the standard cobalt molybdenum catalyst. The conditions of this test were carried out in accordance with the cutlet and other conditions in a normal commercial apparatus. These conditions are as follows.

Gas composition: 3.5% carbon monoxide, 32.5% carbon carbonate, space velocity: 4500

63% hydrogen, 1% hydrogen sulfide steam cutlet: 1: 1

Condition: Pressure 410psig Temperature: 650 ℉

The catalytic amount of the bench scale reactor was 20 cc. The catalyst of Sample 6, i.e., a stabilizing catalyst having an aluminum oxide to rare earth oxide ratio of 25: 1, was charged to tube 1, and a standard cobalt molybdenum catalyst was charged to tube 2. Table 3 depicts the experimental data for this test. The date changed to days. Thus, for example, having a second day twice means taking data on the second day. In some cases, one or two days are omitted if they are probably weekends. In any case, the activity of Tube 1 and Tube 2, namely Sample 6 and Sample 7 catalysts, is essentially equivalent in the range of experimental error throughout the test because the data is shown as it appears in the data. In summary, for example, after 100 hours, the outlet carbon monoxide in sample 6 is 0.86 for 1.19 in sample 7 and 1.36 in sample 7 for outlet carbon monoxide 1.36 in sample 6 at 238 hours. However, their differences are shown in the actual surface area retention and compressive strength retention. Catalyst 6 is 14% for 87% compressive strength retention. Similarly, catalyst 7 is 29% to 73.8% surface area retention of catalyst 6. In the X-ray diffraction of the emitter catalyst, all of the alumina of catalyst 6, which is a stabilizing catalyst, showed a gamma phase, whereas the x-ray diffraction of the emitter catalyst in Sample 7 was partly alumina and partly alpha. The physical conditions and appearance of the catalyst released in Sample 7 were very brittle and the color ranged from light blue to white.

[Examples 8 and 9]

Catalysts of these samples were taken from commercially prepared cobalt molybdenum alumina and the like. The composition of these catalysts is as described in Catalysts 8 and 9 of Table IV, respectively.

[Table 2]

[Table 3]

[Table 4]

General Instability Stabilization

Average compressive strength maintenance rate (%) 16.7 (1) 65.3

Average surface area retention (%) 34.0 62.9

No case of producing alumina alumina

(1) Except for the average of 100 or more test 11 retention rate.

[Examples 10, 11, 12, 13 and 14]

The catalysts in these examples were prepared according to the method shown in Example 1 except that the various compositional components were different. Catalysts 10, 4, 11 and 12 all have a rare earth oxide (REO) to alumina (Al ₂ O ₃ ) ratio of 1:25. However, catalysts 13 and 14 have a REO: Al ₂ O ₃ ratio of 1: 100 and 1:50. It should be noted that three separate experiments were conducted for each catalyst of Examples 8 and 9.

In Examples 8 and 9, the average compressive strength retention of the unstabilized catalyst was 16.7% and the average compressive strength retention of the stabilized catalyst was 65%. The surface area retention of the unstabilized catalyst was 35.2%, while the surface area retention of the stabilized catalyst was 59%. Also, in the unstabilized catalyst, alpha alumina was formed in all cases except the catalyst. However, in the case of the stabilization catalyst, the formation of alpha alumina by X-ray diffraction could not be seen. In order to further show the effect of the small amount of rare earth oxides on the alumina carrier, the catalyst of Example 13 having a REO: Al ₂ O ₃ ratio of 1: 100 was compared with the unstabilized catalyst of Example 8. The fifth table shows that the activity of Catalyst 13 is equivalent to that of Example 8 made by a standard commercial plant. However, the compressive strength retention rate of the catalyst was 72% despite the REO: Al ₂ O ₃ ratio of 1: 100, whereas the catalyst prepared by the plant was 23%. The surface area retention of the stabilized catalyst is 75% and the surface area retention of the unstabilized catalyst is 36%. According to these tests, the catalyst of the present invention consistently has the same activity as the catalyst prepared by the plant, but the catalyst of the present invention exhibits much better compressive strength retention than the commercial catalyst, and shows much better surface area retention than the commercial catalyst. It also exhibits some kind of inhibitory effect in the formation of the alpha phase of alumina with loss of surface area and temperature.

Although the present invention has not been described above as examples and data, many modifications and changes are possible in the present invention without being limited only to these descriptions, and any one of them is included within the scope of the present invention.

[Table 5]

Claims (1)

The molded alumina carrier contains a catalytically active amount of molybdenum oxide as a main component, and the alumina carrier is composed of particles obtained by forming a homogeneous mixture of a gamma phase aluminum oxide and a lanthanum series rare earth metal oxide to be calcined. A stabilized, sulfur-resistant carbon monoxide catalyst.