CN1126595C - Double-function sulphur recovering catalyst and its prepn - Google Patents

Abstract

The present invention relates to a sulfur recovery catalyst and a preparation method thereof, particularly to a sulfur recovery catalyst with the dual functions of high organic sulfide hydrolysis activity and high H2 S and SO2 Claus reactivity and a preparation method of the sulfur recovery catalyst. The catalyst of the present invention comprises titanium oxide, active aluminum oxide and of alkaline metal oxide or alkaline earth metal oxide, wherein the catalyst comprises 10% to 90% of titanium oxide, 9.5% to 89.5% of active aluminum oxide and 0.5% to 10% of alkaline metal oxide or alkaline earth metal oxide by weight. The present invention overcomes the defects of easy sulphatizing poisoning of a common alumina catalyst caused by the existence of trace amount of O2 and SO2 and small specific surface area and low intensity of a pure TiO2 catalyst; compared with the traditional catalyst, the present invention has the advantages of large specific surface area, high intensity, high organic sulfur hydrolysis activity, high Claus activity, strong sulphatizing resistance, etc.

Description

A kind of double-function sulfur recovery catalyst and preparation method thereof

Technical field

The present invention relates to a kind of catalyst for recovering sulfur and preparation method thereof, particularly a kind of have higher organic sulfide hydrolytic activity and a higher H ₂S and SO ₂The active double-function sulfur recovery catalyst of claus reaction and preparation method thereof.

Background technology

In refining of petroleum and gas chemical industry's process, produce a large amount of sour gas that contains H2S, industrial general employing claus process recovery sulphur is also eliminated environmental pollution:

China's sulfur recovery technical development is very fast, up to now, has built up the sulfur recovery unit of cover more than 60, and sulfur recovery rate is all about 94～96% usually.Because the existence of hydro carbons and CO in the sour gas, the organosulfur compound that has generated some amount in the sulfur recovery facility high temperature combustion furnace under 1300 ℃ the hot conditions (is mainly CS ₂, COS), this mainly be since in the sour gas hydro carbons and CO following reaction generation takes place in roasting kiln:

In the industrial sulphur retrieving arrangement, generally remove CS2 and COS and the further elementary sulfur that reclaims and improve total sulfur recovery by the following catalytic hydrolysis reaction that takes place in first catalyticreactor:

In not having the Cross unit of vent gas treatment, the CS that roasting kiln generates ₂Usually will account for more than 20% of tail gas desulphurization amount with COS, if set up the low-temperature Claus tail-gas treatment unit, organic sulfide more will account for more than 50% of tail gas total sulfur loss.Therefore, the active quality of claus catalyst tempreture organic sulphur hydrolysis has become the key of further raising Cross unit total sulfur recovery.Known to the SO in the process gas ₂With micro-O ₂It is the major cause that causes catalyst activity to reduce that the sulphating that causes is poisoned, and for improving the organic sulfur hydrolysis rate of catalyst for recovering sulfur, recent two decades comes, and people are devoted to develop new auxiliary agent type catalyst for recovering sulfur to improve H ₂S transformation efficiency and COS/CS ₂Percent hydrolysis also prolongs life of catalyst, wherein mainly contains TiO ₂-Al ₂O ₃, NaO-Al ₂O ₃, CaO-Al ₂O ₃Catalyzer etc. are wherein especially with TiO ₂-Al ₂O ₃The catalytic effect of catalyzer is best.

U.S.P.4141962 discloses a kind of TiO ₂-Al ₂O ₃The preparation method of auxiliary agent type catalyst for recovering sulfur, this catalyzer is to be 300m with the specific surface area ²/ g, external diameter are the Al of φ 2-4mm ₂O ₃Ball spraying TiCl ₄After drying treatment, and carry out 500 ℃ * 4h roasting and form.With active A l ₂O ₃Compare this TiO ₂-Al ₂O ₃Catalyzer has stronger anti-sulphating poisoning capability, higher tempreture organic sulphur hydrolysis ability and longer life-span.But in this catalyst preparation process because TiCl ₄Deliquescence discharges HCl and exists than the overall situation pollution in air, realizes difficulty of industrialization.

The industrial common activated alumina catalyst that generally uses has certain C S ₂, the COS hydrolysis property, but the active very fast reduction with the increase of duration of service is commonly referred to be the catalyst sulfuric acid salinization and poisons and cause that it is micro-O in the process gas ₂Existence and SO ₂Irreversible adsorption on catalyzer causes.

Summary of the invention

The object of the present invention is to provide a kind of high COS/CS that has ₂Percent hydrolysis and the active catalyst for recovering sulfur of high Crouse and preparation method thereof.

Catalyzer of the present invention is made up of the oxide compound of titanium oxide, activated alumina and alkaline-earth metal, and wherein in catalyst weight: titanium oxide content is 10%～90%, is preferably 10%～50%; The content of activated alumina is 9.5%～89.5%, is preferably 45%～85%; The oxide content of alkaline-earth metal is 0.5%～10%, is preferably 1.0%～5.0%.Wherein said titanium oxide can derive from the metatitanic acid that the industrial sulphuric acid method is produced, and also can derive from the TiCl that industrial chloride processes is produced ₄The metatitanic acid that obtains after the hydrolysis, the metatitanic acid with industry pressurization Production By Sulfuric Acid Process is best especially.Activated alumina of the present invention can derive from the activated alumina of industrial aluminium hydroxide high temperature fast dewatering explained hereafter, also can directly use aluminium hydroxide to do precursor, preferably selects for use pseudo-boehmite aluminium hydroxide to do precursor.The oxide compound of alkaline-earth metal of the present invention is meant the oxide compound of calcium or barium; The precursor of described alkaline earth metal oxide is the soluble compound of alkaline-earth metal preferably, is more preferably salt, as nitrate, muriate, acetate etc., as Ca (NO ₃) ₂, CaCl ₂, Ba (NO ₃) ₂, BaCl ₂, Ca (CH ₃COO) ₂Deng, also can be two or more mixture in the soluble compound.

The specific surface area of catalyzer of the present invention is preferably 200～250m ²/ g, average crushing strength is 120～180N/cm.

Catalyzer of the present invention can be by traditional dipping method preparation, be about to the precursor wiring solution-forming of alkaline earth metal oxide, the carrier that dipping is made by metatitanic acid and aluminum oxide or aluminium hydroxide (also can be pseudo-boehmite aluminium hydroxide), treat that carrying out drying and roasting after the alkaline earth metal compound dipping evenly forms, drying temperature is 100～150 ℃, and maturing temperature is 300～600 ℃.Support of the catalyst can be with industrial metatitanic acid through 100～150 ℃ of dryings after 10～30 hours, mix by proportioning with aluminum oxide or aluminium hydroxide, make by traditional forming method again, as roller forming, extruded moulding etc., after the roasting of carrier after the moulding through 100～150 ℃ drying and 300～600 ℃, can flood alkaline earth metal compound.For guaranteeing dipping evenly, the solution of alkaline earth metal compound can excessive 10%～20% in the preparation process.

Catalyzer of the present invention also can be mixed together evenly by the precursor solution with metatitanic acid dry powder, aluminum oxide or aluminium hydroxide (also can be pseudo-boehmite aluminium hydroxide) dry powder and the alkaline earth metal oxide for preparing, by the banded extruder extruded moulding, catalyzer gets product after drying, the roasting.For guaranteeing that extrusion is smooth and easy, catalyst surface is smooth, can add extrusion aid, as carboxymethyl cellulose, field mountain valley with clumps of trees and bamboo powder, polyacrylamide, polyoxyethylene glycol and whiteruss etc., the add-on of general extrusion aid is 1%～3% of a finished catalyst weight in the extrusion process.The drying temperature of catalyzer is preferably in 100～150 ℃, and be 10～30 hours time of drying, and the maturing temperature of catalyzer is 300～600 ℃.In the drying and roasting process preferably the heat-up rate by 100 ℃/hour carry out, to guarantee that moisture in the catalyzer slowly discharges in order to avoid the intensity of catalyzer is worked the mischief.

This catalyzer is generally at 200～360 ℃ of temperature, gas space velocity 500～3000h ^-1Reaction conditions use down.

Catalyzer of the present invention has overcome common aluminium oxide catalyst because micro-O ₂And SO ₂Existence easily produce sulphating and poison, and pure TiO ₂The shortcoming that specific surface area of catalyst is less, intensity is relatively poor is compared with traditional catalyst, has advantages such as tempreture organic sulphur hydrolysis activity and all higher, the anti-sulphating ability of Crouse's activity are strong.

Embodiment

Following embodiment will carry out concrete description to the present invention, but the present invention is not limited to embodiment itself.

Embodiment 1

The metatitanic acid of industrial employing sulfuric acid process preparation is got metatitanic acid dry powder after 120 ℃ * 12h oven dry, this dry powder 100g and aluminium hydroxide dry powder (industrial pseudo-boehmite AlOOH) 100g thorough mixing is even.Take by weighing crystallization Ca (NO ₃) ₂4H ₂Add in the above-mentioned mixed dry powder after O21g is dissolved in the 120ml distilled water, and adding sesbania powder 2g fully stirs the back φ 4.5mm orifice plate extruded moulding of using after mediating 0.5h on the twin screw banded extruder, 120 ℃ * 12h oven dry then, 400 ℃ * 2h roasting promptly gets catalyst sample A.The specific surface area 205m of this sample ²/ g, average crushing strength 150N/cm.

Embodiment 2

TiCl with industrial employing chlorination process production ₄The metatitanic acid that obtains after the solution hydrolysis carries out getting metatitanic acid dry powder after the 120 ℃ * 12h drying, and this dry powder 100g and aluminium hydroxide dry powder (industrial pseudo-boehmite AlOOH) 100g thorough mixing is even.Take by weighing Mg (NO ₃) ₃4H ₂Join in the above-mentioned mixed dry powder after O 13.8g is dissolved in the 120ml distilled water and add and after mediating 0.5h on the twin screw banded extruder, use φ 4.5mm orifice plate extruded moulding after sesbania powder 2g fully stirs, 120 ℃ * 12h oven dry then, 400 ℃ * 2h roasting promptly gets catalyst sample B.The specific surface area 200m of this sample ²/ g, average crushing strength 145N/cm.

Embodiment 3

The metatitanic acid of industrial employing sulfuric acid process preparation is got metatitanic acid dry powder after 120 ℃ * 12h oven dry, this dry powder 100g and aluminium hydroxide dry powder (industrial pseudo-boehmite AlOOH) 100g thorough mixing is even.Add and after mediating 0.5h on the twin screw banded extruder, use φ 4.5mm orifice plate extruded moulding after distilled water 130ml and sesbania powder 2g fully stir, 120 ℃ * 12h oven dry then, 400 ℃ * 2h roasting promptly gets the specific surface area 210m of this sample of catalyst sample C. ²/ g, average crushing strength 165N/cm.

Embodiment 4

The metatitanic acid of industrial employing sulfuric acid process preparation is got metatitanic acid dry powder after 120 ℃ * 12h oven dry, this dry powder 100g and aluminium hydroxide dry powder (industrial pseudo-boehmite AlOOH) 100g thorough mixing is even.Take by weighing Ba (NO ₃) ₂4H ₂Join in the above-mentioned mixed dry powder after O5.5g is dissolved in the 120ml water and add and after mediating 0.5h on the twin screw banded extruder, use φ 4.5mm orifice plate extruded moulding after sesbania powder 2g fully stirs, 120 ℃ * 12h oven dry then, 400 ℃ * 2h roasting promptly gets the specific surface area 205m of this sample of catalyst sample D. ²/ g, average crushing strength 170N/cm.

Embodiment 5

The metatitanic acid of industrial employing sulfuric acid process preparation is got metatitanic acid dry powder after 120 ℃ * 12h oven dry, this dry powder 100g and aluminium hydroxide dry powder (industrial pseudo-boehmite AlOOH) 100g thorough mixing is even.Take by weighing crystallization Ca (CH ₃COO) ₂4H ₂Add in the above-mentioned mixed dry powder after O 15.8g is dissolved in the 120ml distilled water, and adding sesbania powder 2g fully stirs the back φ 4.5mm orifice plate extruded moulding of using after mediating 0.5h on the twin screw banded extruder, 120 ℃ * 12h oven dry then, 400 ℃ * 2h roasting promptly gets catalyst sample E.The specific surface area 220m of this sample ²/ g, average crushing strength 158N/cm.

Embodiment 6

The metatitanic acid of industrial employing sulfuric acid process preparation is got metatitanic acid dry powder after 120 ℃ * 12h oven dry, this dry powder 100g and aluminum oxide dry powder (activated alumina of industrial employing aluminium hydroxide high temperature fast dewatering prepared) 100g thorough mixing is even.Take by weighing crystallization Ca (NO ₃) ₂4H ₂Add in the above-mentioned mixed dry powder after O 21g is dissolved in the 120ml distilled water, and adding sesbania powder 2g fully stirs the back φ 4.5m orifice plate extruded moulding of using after mediating 0.5h on the twin screw banded extruder, 120 ℃ * 12h oven dry then, 400 ℃ * 2h roasting promptly gets catalyst sample F.The specific surface area 195m of this sample ²/ g, average crushing strength 145N/cm.

Embodiment 7

The metatitanic acid of industrial employing sulfuric acid process preparation is got metatitanic acid dry powder after 120 ℃ * 12h oven dry, this dry powder 1008 is even with aluminium hydroxide dry powder (industrial pseudo-boehmite AlOOH) 100g thorough mixing.Take by weighing crystallization Ca (NO ₃) ₂4H ₂Add in the above-mentioned mixed dry powder after O34g is dissolved in the 120ml distilled water, and adding Walocel MT 20.000PV 4g, fully stir the back and after mediating 0.5h on the twin screw banded extruder, use φ 4.5mm orifice plate extruded moulding, 120 ℃ * 12h oven dry then, 400 ℃ * 2h roasting promptly gets catalyst sample G.

Embodiment 8

The metatitanic acid of industrial employing sulfuric acid process preparation is got metatitanic acid dry powder after 120 ℃ * 12h oven dry, this dry powder 100g and aluminium hydroxide dry powder (industrial pseudo-boehmite AlOOH) 100g thorough mixing is even.Take by weighing crystallization Ca (NO ₃) ₂4H ₂Add in the above-mentioned mixed dry powder after O9g is dissolved in the 120ml distilled water, and adding sesbania powder 2g fully stirs the back φ 4.5mm orifice plate extruded moulding of using after mediating 0.5h on the twin screw banded extruder, 120 ℃ * 12h oven dry then, 400 ℃ * 2h roasting promptly gets catalyst sample H.

Embodiment 9

The metatitanic acid of industrial employing sulfuric acid process preparation is got metatitanic acid dry powder after 120 ℃ * 12h oven dry, this dry powder and aluminium hydroxide dry powder (industrial pseudo-boehmite AlOOH) 100g thorough mixing is even.Take by weighing CH ₃Join in the above-mentioned dry powder that mixes after COONa5.8g is dissolved in the 120ml water and add sesbania powder 3g, fully stir the back and after mediating 20 minutes on the twin screw banded extruder, use Φ 4mm orifice plate extruded moulding, 130 ℃ * 12h oven dry then, 450 ℃ * 3h roasting, promptly get catalyst sample I, the specific surface area of this sample is 230m ²/ g, average crushing strength is 150N/cm.

Embodiment 10

With being ground into the above-mentioned catalyst sample 5ml of 20～40 purposes internal diameter of packing into is in the reactor made of the stainless steel tube of 14mm, on all load the quartz sand mixing preheating of same particle sizes.Reaktionsofen adopts Electric heating, approximate isothermal body of heater.Adopt H in day island proper Tianjin GC-14B gas chromatograph on-line analysis reactor inlet and the exit gas ₂S, SO ₂, COS, CS ₂Content, adopt the GDX-301 carrier to analyze sulfide, adopt the 5A molecular sieve to analyze O ₂Content, 120 ℃ of column temperatures adopt thermal conductivity detector, do carrier gas with hydrogen, flow velocity 28ml/min behind the post.

With Be the index reaction, investigate Crouse's activity of catalyst sample, inlet gas consists of H ₂S2%, SO ₂1%, O ₂1500ppm, H ₂O30%, all the other are N2, the gas volume air speed is 2500h ^-1, temperature of reaction is 230 ℃, calculates Crouse's transformation efficiency of catalyzer according to following formula: ${\mathrm{\η}}_{H2S+\mathrm{SO}2}=\frac{M_0-M_1}{M_0}\×100\%$ M wherein ₀, M ₁Then representative enters the mouth and exit H respectively ₂S and SO ₂Volumetric concentration and.

With Be the index reaction, the tempreture organic sulphur hydrolysis activity of examination catalyst sample, inlet gas consists of CS ₂2%, SO ₂2%, O ₂1500ppm, H ₂O30%, all the other are N ₂, the gas volume air speed is 2500h ^-1, temperature of reaction is 300 ℃, calculates the CS of catalyzer according to following formula ₂Percent hydrolysis: ${\mathrm{\η}}_{\mathrm{CS}2}=\frac{C_0-C_1}{C_0}\×100\%$ C wherein ₀, C ₁Be respectively inlet and exit CS ₂Volumetric concentration.

The activity rating of above-mentioned catalyst sample A～I the results are shown in table 1, and activity data wherein is all the 12 hours mean value of operation continuously.

The activity contrast of table 1. different catalysts sample

Catalyst sample	A	B	C	D	E	F	G	H	I	To M in the same old way *
											Crouse's transformation efficiency, %	80	79	77	79	80	79	78	78	76	75
CS 2Percent hydrolysis, %	95	94	85	93	95	90	90	90	90	70

^*Control sample M is the industrial a kind of catalyst for recovering sulfur that generally uses, and its major ingredient is an activated alumina, down together

Embodiment 11 has investigated differing temps to catalyzer CS according to the evaluation method that embodiment 10 describes ₂The influence of percent hydrolysis the results are shown in table 2.As seen from Table 2 with the rising of temperature, the CS of two catalyzer ₂Percent hydrolysis obviously raises, but the low temperature CS of sample A ₂Hydrolytic activity obviously is better than the industrial comparative catalyst of generally using.

Table 2. temperature is to catalyst sample A and comparative catalyst MCS ₂The influence of hydrolytic activity

Temperature of reaction, ℃	280	300	320	340	360
						The CS of sample A 2Percent hydrolysis, %	77	95	96	98	100
The CS of comparative catalyst M 2Percent hydrolysis, %	58	70	87	92	97

Embodiment 12 has investigated different air speed air speeds to catalyzer CS according to the activity rating method that embodiment 10 describes ₂The influence of percent hydrolysis.The results are shown in table 3.As seen from Table 3, with the increase of gas volume air speed, the tempreture organic sulphur hydrolysis of catalyzer is active to descend, but the activity of sample A obviously is better than the comparative catalyst M of industrial use.

Table 3. air speed is to catalyst sample A and comparative catalyst M CS ₂The influence of hydrolytic activity

Air speed, h -1	1000	1500	2500	3500	5000
						The CS of sample A 2Percent hydrolysis, %	100	99	95	76	60
The CS of comparative catalyst M 2Percent hydrolysis, %	92	88	70	64	43

Claims (12)

1, a kind of catalyst for recovering sulfur, its oxide compound by titanium oxide, activated alumina and alkaline-earth metal is formed, the oxide compound of this alkaline-earth metal refers to CaO or BaO, in catalyst weight: the content of titanium oxide is 10～90%, the content of activated alumina is 9.5～89.5%, and the content of CaO or BaO is 0.5～10%.

2, according to the described catalyzer of claim 1, wherein the content of titanium oxide is 10～50%.

3, according to the described catalyzer of claim 1, wherein the content of activated alumina is 45～85%.

4, according to the described catalyzer of claim 1, wherein the content of CaO or BaO is 1.0～5.0%.

5, according to the described catalyzer of one of claim 1～4, the specific surface area that it is characterized in that catalyzer is 200～250m ²/ g.

6, according to the described catalyzer of claim 1, it is characterized in that use temperature is 200～360 ℃, the use air speed is 500～3000h ^-1

7, the described Preparation of catalysts method of a kind of claim 1, it is characterized in that soluble compound solution with Ca or Ba, the shaping carrier that dipping is made by metatitanic acid and aluminum oxide or aluminium hydroxide, or behind direct the soluble compound solution and the even also moulding of metatitanic acid dry powder, aluminum oxide or aluminium hydroxide dry powder blend with Ca or Ba, carry out drying again, roasting forms, maturing temperature is 300～600 ℃.

8, in accordance with the method for claim 7, wherein the soluble compound of Ca or Ba is the soluble salt that contains Ca or Ba.

9, according to claim 7 or 8 described methods, wherein the soluble compound of Ca or Ba is:

Ca (NO ₃) ₂, CaCl ₂, Ba (NO ₃) ₂, BaCl ₂, Ca (CH ₃COO) ₂Or two or more mixture wherein.

10, in accordance with the method for claim 7, wherein metatitanic acid is the metatitanic acid of industrial sulphuric acid method production or the TiCl of industrial chloride processes production ₄The metatitanic acid of hydrolysis gained.

11, according to claim 7 or 10 described methods, wherein metatitanic acid is the metatitanic acid of industry pressurization Production By Sulfuric Acid Process.

12, in accordance with the method for claim 7, wherein aluminium hydroxide is pseudo-boehmite aluminium hydroxide.