CN1044979C

CN1044979C - Non-molybdenum oxide catalyzer resisting methanation of sulfur and its processing

Info

Publication number: CN1044979C
Application number: CN93110096A
Authority: CN
Inventors: 付桂芝; 刘淑芬; 吕永安; 关迪镛; 袁权
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 1993-02-17
Filing date: 1993-02-17
Publication date: 1999-09-08
Anticipated expiration: 2013-02-17
Also published as: CN1091336A

Abstract

The present invention relates to a non-molybdenum catalyst for a methanation reaction, which uses a chromium base as a main active component, wherein the oxide of V, Ni , Co or Mn is added to the main active component to be used as a cocatalyst. In the preparation process of the catalyst, a forming agent containing acetate fiber or the water solution of polyvinyl alcohol is added for forming. The catalyst is used for the methanation reaction, and precuring and reduction treatment are not needed before the catalyst is used. During the reaction process, the structure of the catalyst is unchanged, and the catalyst has the advantages of high catalytic activity (the conversion rate of CO is greater than 60%), good selectivity (the selectivity of CH4 is greater than 64%), and long service life (the decay rate of the conversion rate of CO is less than 2% after the reaction is carried out for 1000 hours). Therefore, the catalyst has strong practicability in industry.

Description

A kind of coal gas methanation in presence of sulfur chromium base oxide catalyst and preparation thereof

The present invention relates to a kind of catalyst that is used for the coal gas methane reaction.Specifically provide a kind of chromium-based catalysts that does not contain molybdenum element, this catalyst is used for methanation reaction, is oxidation state before and after its reaction, and needn't gives vulcanizing treatment before the reaction.

The industrial in recent years catalyst for methanation in presence of sulfur that is used for is generally the molybdenum sulfide type, is molybdenum oxide before the reaction, through containing H ₂Hydrogen sulfuration and the molybdenum sulfide that is reduced to methanation activity of S.Though this class catalyst with base of molybdenum has higher activity to methanation reaction, need H owing to give sulfuration ₂S and H ₂Source of the gas, this gives coal gas methanation factory, and especially medium and small factory brings great inconvenience.

The purpose of this invention is to provide a kind of gas methanation reaction and use catalyst, this catalyst does not contain molybdenum, and the maximum characteristics of this catalyst are to be oxidation state before and after the reaction, and structure is constant, and needn't give vulcanizing treatment before the reaction.It is used for the catalytic production of methane reaction, not only has very high activity and selectivity, and stronger anti-sulphur effect is arranged again simultaneously.

Non-molybdenum methanation catalyst of the present invention is to adopt chromium-based catalysts, and adds metallic element as co-catalyst in the chromium base, and chromium base active constituent also can be supported on the oxide carrier, the consisting of of its catalyst: (MO _x) 20～100 (AO _y) 0～80, in last expression formula, MO _xFor having the metal oxide of catalytic activity, as the oxide of metals such as Cr, V, Ni, Co, Mn, wherein the weight percent content of each oxide is: Cr 20～100%; V 0～25%; Ni 0～25%; Co 0～25%; Mn 0～25%; AO _yBe carrier, Al ₂O ₂, ZrO ₂, TiO ₂Or CeO ₂Deng, x, y be oxide contain oxygen number, active component MO _xThe total weight percent that accounts for catalyst is 20～100%, carrier AO _yThe total weight percent that accounts for catalyst is 0～80%.

Preparation of catalysts of the present invention is pressed following step:

1. when catalyst contains carrier, earlier support oxide is carried out calcination process, roasting is carried out under 400～800 ℃;

2. by measuring a certain amount of soluble salts of active components that contains containing of active component in the catalyst, make solution, utilize infusion process that active component is supported on carrier;

3. when catalyst does not contain carrier, take by weighing the salt that contains the active component element by the content of each active component in the catalyst, be generally ammonium salt or nitrate and mix;

4. obtain material with above-mentioned 2 or 3 and carry out roasting, roasting is carried out under 400～800 ℃, and roasting time makes active component all be converted into oxide to be no less than 2 hours;

5. 4 resulting oxides are added and contain organic forming agent mixing, kneaded and formed, after drying, under 400～800 ℃, carry out roasting again and be no less than 2 hours, can obtain catalyst of the present invention.Above-mentioned forming agent is for containing aqueous organic, for example acetate fiber or polyvinyl alcohol water solution etc., and organic content is 1～15% (weight), all the other are water, and water is preferably selected deionized water for use.Below by embodiment technology of the present invention is given to illustrate in further detail.

Example 1 Preparation of catalysts 1

Prescription Cr ₂O ₃---V ₂O ₃/ γ---Al ₂O ₃

20 5 75 (weight %)

Earlier the γ-Al of powdery ₂O ₃, 500 ℃ of roastings 3 hours, again with the quantitative (NH of dissolved in distilled water ₄) ₂Cr ₂O ₇And NH ₄VO ₃, flood, after spending the night, baking oven puts 500 ℃ of roastings of Muffle furnace 4 hours, if solution amount is excessive, but step impregnation.Till institute's palpus solution amount all immerses, with the weak solution that contains acetate fiber 5% the catalyst powder mixing is mediated extrusion afterwards, got final product in 4 hours in 500 ℃ of roastings again after the oven dry.

Example 2 Preparation of catalysts 2

Prescription Cr---Ni---Mn (being oxide weight %)

65 15 20

Take by weighing ammonium dichromate by prescription, barium acid ammonium and manganese nitrate are put into the roasting device behind the mixing, and stirring slowly heats up down decomposes.Decompose the cooling that finishes transfer in the Muffle furnace 500 ℃ 4 hours.

Make the aqueous solution that contains polyvinyl alcohol 10% with an amount of dissolve polyvinyl alcohol of hot water, the catalyst powder that makes is stirred evenly extrusion with this solution.Again in 500 ℃ of Muffle furnace roastings 4 hours, catalyst gets product after the oven dry.

Example 3 Preparation of catalysts 3

Prescription Cr---V (oxycompound weight %)

85 15

Quantitatively take by weighing ammonium dichromate and ammonium metavanadate, its catalyst preparation process and moulding process are all with example 2.

Example 4 Preparation of catalysts 4

Catalyst formulation and preparation method only replace poly-vinyl alcohol solution with the aqueous solution that contains acetate fiber 5% all with example 3 when moulding.Catalyst powder: solution=1～3: 1.

Example 5 Preparation of catalysts 5

Prescription Cr---Mn---Co (oxycompound weight %)

60 30 10

Take by weighing quantitative chromic nitrate, manganese nitrate, cobalt nitrate, dissolve in beaker, Jia Shuichong releases to 4 times of original volumes, heats 40～60 ℃, drips～30% concentrated ammonia liquor and makes it precipitation, filters, and washes with water to neutrality, puts baking oven and spends the night for 110 ℃, again in 500 ℃ of roastings 4 hours.Use the aqueous solution of box polyvinyl alcohol 5% adhesion-molded afterwards, in 500 ℃ of roastings 4 hours, be finished catalyst behind the disconnected bar after the extrusion.

Example 6 Preparation of catalysts 6

Prescription Cr ₂O ₃---NiO/ZrO ₂(weight %)

20 2 78

This catalyst is with 500 ℃ of baked ZrO ₂Make carrier, use the equivalent impregnation method, immerse quantitative potassium bichromate and nickel nitrate, immerse the back oven for drying, 500 ℃ of roastings of Muffle furnace 4 hours add the aqueous solution mixing extrusion that contains polyvinyl alcohol 5% afterwards, get final product in 500 ℃ of roastings after the oven dry again.

Example 7 Preparation of catalysts 7

Prescription Cr---Ni/CeO ₂

20 2 78

Quantitatively take by weighing chromic nitrate, nickel nitrate, cerous nitrate, add 4 times of water again towards rare after the water dissolving, solution is heated to 50～60 ℃, slowly splash under stirring～30%, ammoniacal liquor is complete to precipitation, and washing precipitation is extremely neutral, oven dry, 500 ℃ of roastings 4 hours add the aqueous solution mixing, the extrusion that contain polyvinyl alcohol 1%.Air room temperature airing, 100 ℃ of baking ovens spend the night, and put 500 ℃ of roastings of Muffle furnace again and get product in 4 hours.

Example 8 differences are given the Effect on Performance of processing to catalyst

Utilize the prepared catalyst of example 1, (contain H with unstripped gas ₂: 69.8 (wt%, down together); N ₂: 3.8; CO:19.4; CH ₄: 3.7; CO ₂: 3.3; H ₂S:0.5), under reaction condition T:400 ℃; P:1.0MPa; SV:1000hr ^-1Carry out methanation reaction.Catalyst is carried out different disposal relatively to give processing to Effect on Performance, its structure such as table 1 before reaction.

Table 1 difference is given processing to be influenced catalyst activity

Give processing procedure ^*1	A	B	C	D
Give processing procedure ^*1	A	B	C	D	X _CO(％) ^*2	68.2	68.1	68.3	68.4
S _CH4(％) ^*3	70.4	74.0	73.1	73.2	X _CO(％) ^*2	68.2	68.1	68.3	68.4

* 1 A: in catalyst preparation stages sulfuration and reduction

B: sulfuration and reduction before the reaction

C: only reduce before the reaction

D: unstripped gas natural vulcanization

* 2 X _COBe the CO conversion ratio

* 3 S _CH4Be methane selectively

Example 9 different forming agent moulding are to the influence of catalyst performance

Utilize example 2 described methods and formulation to go out catalyst, but according to the form below 2 described methods add different forming agent aftershapings, and carry out methanation reaction with example 7 described reaction conditions, its relative activity is listed in table 2.

Table 2 forming agent is to the influence of the catalytic activity of catalyst

Forming method	Extrusion
Forming method	Extrusion					The forming agent relative activity	Trace graphite 1.0	Acid inorganic matter 0.2	Alkalescence inorganic matter 0	Neutral inorganic matter 0.55	The present invention 1.3～1.5

Example 10 activity of such catalysts, selectivity and stability

Utilize the prepared catalyst of example 3～7, carry out methanation reaction by example 8 described reaction conditions, the conversion ratio of the average result of its each catalyst: CO is greater than 60%; CH ₄Selectivity greater than 64%, the conversion ratio attenuation rate of thousand hours CO of reaction induced after date is less than 2%.

By above-mentioned example, its preparation process of catalyst provided by the invention is simple, the gained catalyst is used for methanation reaction, need not give sulfuration and reduction processing before using, and this has just been avoided the necessary technological operation of vulcanizing with costliness and the strong hydrogen sulfide of corrosivity of general sulfur resistant catalyst.Simultaneously, the catalytic activity height of catalyst (the CO conversion ratio is greater than 60%), the good (CH of selectivity ₄Selectivity greater than 64%), the life-span long (the conversion ratio attenuation rate of reacting CO after thousand hours is less than 2%).Therefore, this catalyst has a very strong practicality industrial.

Claims

1. chromium base oxide catalyst that is used for gas methanation, it is characterized in that: this catalyst is made of active component and carrier, and described carrier is to be selected from Al ₂O ₃, ZrO ₂, TiO ₂Or CeO ₂Described active component is the oxide that is selected from Cr, V, Ni, Co or Mn metal, in catalyst activity component+vehicle weight, chromated oxide is 20～100wt%, barium oxide is 5～25wt%, nickel oxide is 2～25wt%, titanium oxide is 10～25wt%, or Mn oxide is 20～25wt%, and all the other weight are carrier.