RU2269377C2 - Catalyst for synthesis of hydrocarbons from co and h2 (fischer-tropsch synthesis) - Google Patents

Abstract

FIELD: industrial organic synthesis catalysts.

SUBSTANCE: in order to increase CO-into-hydrocarbons conversion, invention provides alumina-supported catalyst containing 10-20% active Co component (calculated as CoO), 0.1-1.0% promoter F, and 0.3-1.0% platinum group metal or first transition series metal promoters or mixtures thereof.

EFFECT: increased CO conversion.

2 tbl, 8 ex

Description

The invention relates to the chemical industry, in particular to the composition of the catalysts, and can be used to convert synthesis gas to alcohols and hydrocarbons.

Known catalytic composition consisting of cobalt in an amount of 1-50 wt.%, Tantalum in an amount of 0.05-5 wt.% And the addition of an inert carrier up to 100%, consisting of silicon dioxide, aluminum oxide, titanium dioxide and the corresponding mixtures [1].

Closest to the invention in technical essence and the achieved effect is a catalyst for the conversion of synthesis gas to hydrocarbons by Fischer-Tropsch synthesis, which is a cobalt of 12-40 wt.%; platinum group metal: platinum, iridium, rhodium or a mixture thereof 0.1-1.9 wt.%; the rest is γ-alumina. Moreover, the catalyst contains 0.25–4.75% of a platinum group metal of the cobalt content and 1% of promoters from a mixture of rare earth oxides [2].

The disadvantages of the considered catalysts include a low degree of conversion of CO to alcohols and hydrocarbons.

To eliminate this drawback, a catalyst is proposed consisting of the active component Co, promoter F with the addition of promoters from platinum group metals (platinum, palladium) or the first transition series (copper, chromium, zinc, titanium), or mixtures thereof and containing an alumina support the following content of components, wt.%:

Active component (in terms of CoO) 10-20 Promoter F 0.1-1.0 Promoter metals of the platinum group or first transition row, or mixtures thereof 0.3-1.0 Carrier rest

It was found that the addition of fluorine in a concentration of from 0.1 to 1 wt.% To the catalyst leads to a significant increase in the conversion of CO. Fluorine can be added both in the preparation of the starting medium and directly in the preparation of the catalyst composition.

The temperature of carrying out the reaction can range from 150 to 300 ° C as for conventional Fischer-Tropsch synthesis catalysts, a pressure of 1 to 100 atm and a space velocity of the synthesis gas from 100 to 2000 h ^-1 .

The proposed catalytic composition can be prepared both by mixing and by impregnation.

The method of preparation of the catalysts by mixing consists in the fact that the reagents that make up the composition are mixed with the precursor γ-Al ₂ About ₃ boehmite in a predetermined ratio in the form of an aqueous solution of nitric acid salts of the corresponding metals, (the promoter) fluorine is added in the form of HF, after which the composition is formed and calcined at t 450 ° C for 4 hours. Under these conditions, boehmite transforms into γ-Al ₂ O ₃ , and the nitrate salts of metals decompose to form oxides of the corresponding metals.

The method of preparation of the catalysts by impregnation consists in the fact that first the carrier γ-Al ₂ O _{3 is} made from boehmite by calcination at t 450 ° C for 4 hours. Moreover, the (promoter) fluorine, if used in the composition, is mixed with boehmite in the form of HF before calcination. Next, the calcined support is cooled to room temperature, and then the ingredients used in the compositions are applied in the form of aqueous solutions of metal nitrate salts. The resulting compositions are calcined at 450 ° C for 4 hours. Under these conditions, nitrate salts of metals decompose to form oxides of the corresponding metals.

Before testing, the catalysts are reduced in a stream of hydrogen at 200 ° C for 1 hour, then the temperature rises to 450 ° C and catalyst recovery continues for another 2 hours.

Testing of the obtained catalysts was carried out in a flow-type reactor at P = 10 atm, T = 175 ° C, V of catalyst 25 cm ³ , the volumetric rate of synthesis gas was 100 h ^-1 . The composition of the synthesis gas corresponded to a hydrogen concentration of 67 vol. % and concentration of CO 33 vol. %

Example 1

An impregnated catalyst composition containing 15 wt.% Cobalt (in terms of CoO) supported on alumina without fluorine. The rest is aluminum oxide.

Example 2

A catalytic composition made by mixing, containing 15 wt.% Cobalt (in terms of CoO) and 0.27 wt.% Fluorine. The rest is aluminum oxide.

Example 3

A catalytic composition made by mixing, containing 15 wt.% Cobalt in terms of CoO and 0.1 wt.% Fluorine, platinum 0.3 wt.%. The rest is aluminum oxide.

Example 4

An impregnated catalyst composition containing 15 wt.% Cobalt in terms of CoO and 1.0 wt.% Fluorine, 1.0 wt.% Palladium. The rest is aluminum oxide.

Example 5

An impregnated catalyst composition containing 10 wt.% Cobalt in terms of CoO and 1 wt.% Fluorine. 1.0 wt.% Copper. The rest is aluminum oxide.

Example 6

A catalytic composition made by mixing, containing 20 wt.% Cobalt in terms of CoO and 0.27 wt.% Fluorine and a mixture of 0.3 wt.% Palladium and 0.7 wt.% Chromium. The rest is aluminum oxide.

Example 7

A catalytic composition made by mixing, containing 15 wt.% Cobalt in terms of CoO and 0.27 wt.% Fluorine and a mixture of 0.3 wt.% Palladium and 0.7 wt.% Zinc. The rest is aluminum oxide.

Example 8

An impregnated catalyst composition containing 15 wt.% Cobalt in terms of CoO and 1 wt.% Fluorine. 1.0 wt.% Titanium. The rest is aluminum oxide.

Table 1 shows the results of the influence of fluorine and promoters, consisting of platinum group metals, metals of the first transition series or their mixtures, on the conversion of CO in synthesis gas, obtained under the same conditions (T, ° С and linear velocities). As can be seen from a comparison of Example 1 and Example 2 (Table 1), fluorine is a promoter of cobalt Fischer-Tropsch synthesis catalysts, since its introduction has a noticeable effect on the increase in CO conversion. From examples 2 and 3-9 (Table 1) it is seen that the addition of platinum group metals, metals of the first transition series or from mixtures significantly increases the conversion of CO to SFT.

Table 1
The effect of fluorine on the conversion of CO in synthesis gas Example No. The cobalt content, wt.% Promoter The fluorine content, wt.% CO conversion,% Name Amount wt.% one fifteen - - 0 55.7 2 fifteen - - 0.27 71.6 3 fifteen Pt 0.3 0.27 85.9 four fifteen Pd one 1,0 95.6 5 10 Cu 1,5 1,0 78,4 6 twenty Cr 0.7 0.27 89.1 Pd 0.3 7 fifteen Zn 0.7 0.27 75.3 Pd 0.3 8 fifteen Ti one 1,0 74.6 table 2
Comparative data on the conversion of CO known and the proposed catalyst composition Known Catalyst The proposed catalyst Composition, wt.% CO conversion,% Composition, wt.% CO conversion,% Co - 20 Pt - 0.17 40 Co - 15, Pt - 0.3, F - 0.27 85.9 Co - 20 Rh - 0.33 53 Co - 15, Pd - 1, F - 1 95.6 Co - 20 Ir - 0.33 53 Co - 20, Cr - 0.7, Pt - 0.3, F - 0.27 89.1

Comparative data on the conversion of CO known and the proposed catalytic composition are presented in table 2. As can be seen from a comparison of the data of the proposed catalytic composition and the prototype, the introduction of fluorine, platinum group metals, metals of the first transition row or mixtures thereof significantly increases the synthesis gas conversion (Table 2) in SFT.

Information sources

1. RU 99107565, class B 01 J 23/847, 2001.

2. RU 2024297, cl. B 01 J 23/89, 1994.

Claims (1)

A catalyst for the synthesis of hydrocarbons from CO and H ₂ (Fischer-Tropsch synthesis), consisting of the active component Co, a promoter and a carrier, characterized in that F is used as a promoter with additions of promoters from platinum group metals, or metals of the first transition series, or mixtures thereof, and the containing carrier is alumina in the following components, wt.%: Active component (in terms of CoO) 10-20 Promoter F 0.1-1.0 The promoter metals of the platinum group or the first transition series, or mixtures thereof 0.3-1.0 Carrier Rest