CN1724155A - Sulphur resisting catalyzing deoxidation agent and its production process - Google Patents

Abstract

A sulfur-resistant catalytic deoxidizing agent for removing O2 from the H2 contained gas and synthetic gas is proportionally composed of active alumina as carrier and the active component (Pt and Mo). Its advantages are high effect and high resistance to S.

Description

Sulfur-resistant catalytic deoxidizer and production method thereof

The invention relates to the technical field of catalysis, in particular to a sulfur-resistant catalytic deoxidizer and a production method thereof.

The deoxidizers in the background art are mainly classified into two types according to the deoxidation principle: one is catalytic hydrodeoxygenation, commonly known as flameless combustion; one is chemical absorption deoxidation. The noble metal deoxidizer is mainly carried out according to catalytic hydrodeoxygenation. In the presence of catalytic deoxidant, hydrogen and oxygen react to produce water with the reaction equation as follows:

most of the catalysts adopt noble metals such as platinum, palladium and the like as active components. The noble metal deoxidizer has the characteristics of wide operation temperature range (from normal temperature to 280 ℃), high space velocity, low residual oxygen amount, no need of regeneration and the like. Platinum and/or palladium are generally used as the noble metal, but when palladium alone is used, strict requirements are imposed on the impurity content in the gas component, particularly sulfur, which is required to be less than 1 ppm. The platinum deoxidizer has sulfur resistance and wider application range. However, the deoxidation depth of the previously prepared platinum-based catalytic deoxidizer is only less than 10ppm, and the sulfur resistance is limited to a certain extent.

The chemical absorption deoxidation is generally that under the condition of no hydrogen, the active component in the deoxidant reacts with oxygen, and the oxygen is absorbed. Taking copper as an active component as an example, CuO should be reduced to elemental copper before deoxidation. The copper microcrystal has high surface free energy due to high dispersity and can react with O at normal temperature₂And reacts quickly to produce copper oxide. After the copper powder is used for a period of time, the elementary copper microcrystals are gradually oxidized, the deoxidation depth is reduced, and hydrogen gas is introduced for regeneration. The reaction equation of oxygen absorption and regeneration is as follows:

the chemical absorption deoxidation active components comprise iron, manganese, nickel, copper and the like. According to the difference of active components, it can be divided into iron series, copper series, manganese series, nickel series, etc. Iron, when used as the active component, may be present in the form of a compound. The non-noble metal deoxidizer has good deoxidation depth and low price, but needs periodic regeneration, and some catalysts can also generate active components to run off, thereby influencing the final quality of products.

The catalyst of the invention selects platinum and molybdenum as active components, and the composition of the two components can realize the synergistic effect: the method can be used for sulfur-containing atmosphere, and has low requirement on inlet sulfur content; meanwhile, the device has strong adaptability to the inlet oxygen content and strong deoxidation capability, and the deoxidation depth can reach below 0.1 ppm.

The catalyst of the present invention has sulfur resistance, and can be used for sulfur-containing occasions to convert organic sulfur into organic sulfurH₂S。

The catalyst of the invention also has the characteristics of simple preparation method, easy control of process conditions and the like.

The invention relates to a sulfur-resistant catalytic deoxidizer, which is characterized in that active alumina is taken as a carrier, dipped simple substances or platinum and molybdenum in a combined state are taken as composite active components, the weight percentage of the catalyst is taken as a reference, the deoxidizer comprises 0.03 to 0.5 percent of metal platinum and 0.5 to 15 percent of molybdenum,and the BET specific surface area of the catalyst is 250 to 300m²A pore volume of 0.40-0.90 cm/g³The per gram, the average pore diameter is 5-20 nm, and the lateral pressure strength of the product is more than 100N/cm.

The invention also relates to a production method of the sulfur-resistant catalytic deoxidizer, which is characterized in that the catalyst is prepared by the following steps:

a. the specific surface area is 250m²More than g, pore volume of 0.40cm³Drying the activated alumina carrier with more than one gram and an average pore diameter of 5-20 nm;

b. dissolving the chloroplatinic acid with calculated amount into a certain amount of deionized water, uniformly stirring, adjusting the pH value to 7.0-10.0, and adding the ammonium molybdate solution with calculated amount;

c. dipping the activated alumina carrier by an isometric method for 6-12 hours, and placing the dipped alumina carrier at room temperature for 12-24 hours;

d. drying the water in an air atmosphere at the temperature of 110-120 ℃;

e. the temperature is programmed to 400-800 ℃ within 6 hours, and the mixture is roasted for 6-9 hours;

f. the catalyst needs pre-reduction before use, and the reduction is realized in a hydrogen atmosphere: gradually heating to 280 ℃ by using nitrogen containing 5-10% (volume ratio) of hydrogen, staying for 4 hours, and then heating to 450 ℃ until the reduction is complete.

g. After the reduction is finished, 0.5 percent of hydrogen sulfide is added into nitrogen to be vulcanized for more than 4 hours at 180 ℃ to obtain the finished deoxidizer.

The preferable scheme of the sulfur-resistant catalytic deoxidizer is characterized in that the deoxidizer comprises 0.05 to 0.4 weight percent of metal platinum and 0.6 to 13 weight percent of molybdenum, and the BET specific surface area of the catalyst is 260 to 290m²The pore volume is 0.45-0.85 cm³(iv)/g, the average pore diameter is 6 to 18 nm.

As a preferable mode of the above-mentioned production method of the sulfur-tolerant catalytic deoxidant of the present invention, characterized in that the catalyst is prepared by the steps of:

h. the specific surface area is 280m²More than g, pore volume of 0.70cm³Drying the activated alumina carrier with more than one/g and the average pore diameter of 6-18 nm;

i. dissolving the chloroplatinic acid with calculated amount into a certain amount of deionized water, uniformly stirring, adjusting the pH value to 8.0-9.5, and adding the ammonium molybdate solution with calculated amount;

j. dipping the activated alumina carrier by an isometric method for 8-10 hours, and standing for 14-22 hours at room temperature;

k. the temperature is programmed to 450-750 ℃ within 6 hours, and the mixture is roasted for 7-8 hours; compared with the prior art, the catalyst prepared by the invention has the following characteristics:

the deoxidizer has sulfur resistance and can convert organic sulfur into inorganic sulfur;

m, can be used for removing oxygen in a sulfur-containing atmosphere, has low requirements on the inlet sulfur content and the sulfur form, can basically convert organic sulfur into hydrogen sulfide, and does not influence the deoxidation activity;

n, strong adaptability to inlet oxygen content, from 5000ppmO₂Can be reduced to below 0.1 ppm.

Examples this patent is further illustrated below by way of examples.

Example 1

The selected active alumina carrier produced by a nitric acid method is 100 g, and the physical indexes are as follows: specific surface area 290m²Per g, pore volume of 0.80cm³(ii)/g, average pore diameter 11 nm; dissolving 0.06 g of metal platinum by aqua regia, adjusting the pH value to 8.0, adding ammonium molybdate solution (7 g based on metal molybdenum), diluting to 100 ml by deionized water, soaking for 8 hours in the same volume, standing for 12 hours at room temperature, drying, and roasting for 9 hours at 400 ℃ to obtain the catalyst. Numbered PTO-1.

Example 2

100 g of spherical activated alumina is selected asThe carrier has the following physical indexes: specific surface area 302m²Per g, pore volume is 0.46cm³(ii)/g, average pore diameter 6 nm; 0.07 g of platinum and 5 g of molybdenum were loaded and calcined at 800 ℃ for 6 hours, and the other preparation steps were the same as in example 1, and the sample was named PTO-2.

Example 3

This example evaluates the deoxidation performance in a fixed bed reactor with the following atmosphere:

gas composition: CO: 47%, H₂：48％，CO₂：1.7％，COS：10ppm，O₂: 2000 ppm. Evaluation conditions were as follows: pressure: normal pressure; temperature: 190 ℃; space velocity: 8000h^-1(ii) a The outlet oxygen content was analyzed with a trace oxygen analyzer, and the results were as follows:

PTO-1：0.04ppm；

PTO-2：0.07ppm。

example 4

This example uses a high sulfur atmosphere to evaluate its deoxygenation performanceon a fixed bed reactor:

the deoxidizer is pre-vulcanized for 4 hours at 150-380 ℃ by using hydrogen sulfide before filling.

Gas composition: CO: 45% of H₂：48％，CO₂: 1.7%, COS: 200ppm, mercaptan 100ppm, O₂：2000ppm。

Evaluation conditions were as follows: pressure: 0.5 MPa; temperature: 240 ℃; space velocity: 5000h^-1(ii) a The outlet oxygen content was analyzed with a trace oxygen analyzer, and the results were as follows:

PTO-1：0.05ppm；

PTO-2：0.06ppm；

conversion rate of mercaptan: 98 percent;

conversion rate of COS: more than 99 percent.

Example 5

This example uses industrial hydrogen to evaluate its deoxygenation performance on a fixed bed reactor:

gas composition: o is₂The content is as follows: about 5000 ppm;

evaluation conditions were as follows: normal temperature, normal pressure, airspeed: 10000h^-1；

The outlet oxygen content was analyzed with a trace oxygen analyzer, and the results were as follows:

PTO-1：0.03ppm；

PTO-2：0.05ppm。

Claims (4)

1. a sulfur-resistant catalytic deoxidizer is characterized in that active alumina is used as a carrier, a dipped simple substance or a compound platinum and molybdenum thereof are used as composite active components, the weight percentage of the catalyst is taken as a reference, the catalyst comprises 0.03 to 0.5 percent of metal platinum and 0.5 to 15 percent of molybdenum, and the BET specific surface area of the catalyst is 250 to 300m²A pore volume of 0.40-0.90 cm/g³The per gram, the average pore diameter is 5-20 nm, and the lateral pressure strength of the product is more than 100N/cm.

2. The method for producing a sulfur-tolerant catalytic deoxidizer according to claim 1, characterized in that the catalyst is prepared by the steps of:

a. the specific surface area is 250m²More than g, pore volume of 0.40cm³Drying the activated alumina carrier with more than one gram and an average pore diameter of 5-20 nm;

b. dissolving the chloroplatinic acid with calculated amount into a certain amount of deionized water, uniformly stirring, adjusting the pH value to 7.0-10.0, and adding the ammonium molybdate solution with calculated amount;

c. dipping the activated alumina carrier by an isometric method for 6-12 hours, and placing the dipped alumina carrier at room temperature for 12-24 hours;

d. drying the water in an air atmosphere at the temperature of 110-120 ℃;

e. the temperature is programmed to 400-800 ℃ within 6 hours, and the mixture is roasted for 6-9 hours;

f. the catalyst needs pre-reduction before use, and the reduction is realized in a hydrogen atmosphere: gradually heating to 280 ℃ by using nitrogen with the hydrogen-containing gas volume ratio of 5-10%, staying for 4 hours, and then heating to 450 ℃ until the reduction is complete;

g. after the reduction is finished, 0.5 percent of hydrogen sulfide is added into nitrogen to be vulcanized for more than 4 hours at 180 ℃ to obtain the finished deoxidizer.

3. According to claim 1The sulfur-resistant catalytic deoxidizer is characterized in that the weight percentage of the catalyst is taken as the reference, the weight percentage of the catalyst comprises 0.05-0.4 percent of metal platinum, 0.6-13 percent of molybdenum, and the BET specific surface area of the catalyst is 260-290 m²The pore volume is 0.45-0.85 cm³(iv)/g, the average pore diameter is 6 to 18 nm.

4. The method for producing a sulfur-tolerant catalytic deoxidizer according to claim 2, characterized in that the catalyst is prepared by the steps of:

h. the specific surface area is 280m²More than g, pore volume of 0.70cm³Drying the activated alumina carrier with more than one/g and the average pore diameter of 6-18 nm;

i. dissolving the chloroplatinic acid with calculated amount into a certain amount of deionized water, uniformly stirring, adjusting the pH value to 8.0-9.5, and adding the ammonium molybdate solution with calculated amount;

j. dipping the activated alumina carrier by an isometric method for 8-10 hours, and standing for 14-22 hours at room temperature;

k. the temperature is programmed to 450-750 ℃ within 6 hours, and the mixture is roasted for 7-8 hours.