CN1317367A

CN1317367A - Selective hydrocatalyst of acetylene

Info

Publication number: CN1317367A
Application number: CN00112846A
Authority: CN
Inventors: 陶家林; 于作龙; 林世浒; 康星武; 瞿美臻; 李庆; 高利珍
Original assignee: Chengdu Institute of Organic Chemistry of CAS
Current assignee: Chengdu Institute of Organic Chemistry of CAS
Priority date: 2000-04-13
Filing date: 2000-04-13
Publication date: 2001-10-17

Abstract

A catalyst for preparing ethylene by selective hydrogenation of acetylene containing CO (0-50%) and ethylene (0-99%) is a Pd/ZnO catalyst, which may contains alkali metal, alkali-earth metal, and the oxide, hydroxide, carbonate, and other inorganic salts of rare-earth element, and the metal, oxide and inorganic salt of transition elements including Ag, Cu, Au, Sn, Pb, Cr, Ni, Co, Fe and Mo.

Description

A kind of selective hydrocatalyst of acetylene

The present invention relates to a kind of selective hydrogenation of acetylene and generate catalyst for ethylene, this catalyst is the Pd of ZnO load, be fit to many preparing ethylene by selective hydrogenation that contain the acetylene unstripped gas, especially be fit to contain the higher unstripped gas of a large amount of CO and ethene and concentration of acetylene, as the selective hydration of acetylene in the natural cyclone flame partial oxidation reactor waste heat oil spout process tail gas.

The selective hydrogenation of acetylene is the research topic of petrochemical process always in the presence of alkene, and for example the steam cracking of naphtha must selectivity be removed acetylene, to reach the specification requirement to ethene from the higher cut of ethylene contents.The metallic element of ⅷ in the periodic table of elements is generally adopted in the selective hydrogenation of acetylene in the presence of ethene, and wherein palladium is the metallic element that activity is best, selectivity is the highest.Because thereby pure Pd causes ethene and acetylene polymerization to influence catalyst life easily, so general extremely thin Pt-supported catalyst, the load capacity 0.01%～0.5% of adopting.Wherein carrier is not merely to play a part dispersed metal Pd, but participated in the formation in activated centre, can promote the generation of polymerisation such as the acidity of carrier, thereby catalyst life is shortened, thereby the character of carrier has extremely important influence to the characteristic of catalyst.Research and industrial employed carrier have following a few class at present: 1, Al ₂O ₃(α, θ), surface area is usually at 8-30M ²Between/the g, (fiber η-Al is also adopted in the part basic research ₂O ₃γ-Al with the high pore volume of low surface area ₂O ₃); 2, SiO ₂3, molecular sieve (float stone); 4, CaCO ₃, α-Al wherein ₂O ₃Be to use the most a kind of carrier.But these carrier loaded Pd catalyst are easy to cause the unsaturated hydrocarbons symphysis of birdsing of the same feather flock together to become green oil to cover the Pd metal surface to make catalysqt deactivation, so industrially must repeat regeneration, the regeneration period that has only is one month.The particularly important is this class catalyst and easily be the anthracemia inactivation of high concentration (though the CO of trace, be generally 1～3ppm as concentration, by being poisoned slightly, improves Pd selectivity of ethylene, suppress the acetylene over-hydrogenation and become ethane), though also there is activity in this class catalyst at high concentration CO simultaneously, but be easy to excessive hydrogenation, and catalyst is extremely short service life, EP0225143 adopts industrial Pd/ α-Al ₂O ₃Catalyst is actively to descend 80% in 2 hours under 29% the unstripped gas in CO concentration.These problems all depend on new catalyst invention.The present invention relates to the carrier that was not used that a kind of carried metal Pd is used for acetylene selective hydration system ethene.

We have now found that in the presence of high concentration CO and ethene selective hydrogenation of acetylene is had catalyst active and stability, are applicable to that also CO and ethene portion do not comprise or only contain the preparing ethylene by selective hydrogenation of acetylene of any unstripped gas.

Therefore, the invention provides and a kind ofly have the wide spectrum characteristic and be applicable to the various catalyst that contain the preparing ethylene by selective hydrogenation of acetylene unstripped gas.

The catalyst that the present invention uses is the Pd catalyst of ZnO load.Wherein ZnO preparation can adopt Zn salt with aqueous alkali precipitation, washing, moulding, drying, air atmosphere or N ₂Roasting technique under the atmosphere, wherein binding agent can add when precipitation, also can add when moulding; Also can directly adopt the roasting of Zn salt, add binding agent moulding, drying, air atmosphere or N ₂Roasting technique under the atmosphere.The oxide of additive basic metal, alkaline-earth metal, rare earth element, hydroxide, and inorganic salts, the metal of Sn, Pb, Cr, Ni, Co, Ga, Fe, Mo or oxide and inorganic salts all can add when the ZnO preparing carriers, or load adding again after the ZnO preparing carriers is finished; Additive A g, Cu, Au, Sn, Pb generally adopt the dip loading method, and these additives can (can be PdCl with Pd salt ₂, Pd (NO ₃) ₂Or oxalic acid palladium) adds simultaneously or add respectively, perhaps used H at Pd ₂, H ₂/ N ₂, H ₂N-NH ₂Add after the prereduction.All components adds to be finished back, drying, adopts air atmosphere or N again ₂Roasting or roasting technique not under the atmosphere.Available H after Preparation of Catalyst is finished ₂, H ₂/ N ₂, H ₂N-NH ₂Prereduction or under reaction temperature, directly feed unstripped gas.Activity of such catalysts component Pd content is 0.01%～3% of vehicle weight, is generally 0.03%～0.5%, the suitableeest 0.03%～0.2%.Suitable catalyst embodiment comprises: ZnO carrier, 0.05%Pd/ZnO, in contrast 0.05%Pd/ α-Al arranged ₂O ₃

This catalyst can be used for containing 0～50% carbon monoxide, contains 0～99% ethene, the unstripped gas preparing ethylene by selective hydrogenation of acetylene that contains carbon monoxide and ethene or neither contain simultaneously, unstripped gas obtains by gaseous state or liquid hydrocarbon cracking or parpartial arithmetic, is natural gas rotary flame furnace tail gas and petroleum cracking ethene as unstripped gas.

This catalyst is used for not containing 10～160 ℃ of its serviceability temperatures of CO (containing or do not contain ethene), best 20～90 ℃.Be used to contain the CO unstripped gas, usually greater than 100～300 ℃ of 5% (containing or do not contain ethene) its serviceability temperatures, best 10～250 ℃.

The reaction pressure that this catalyst is used for acetylene oxidation system ethene is 100～10000h in 0.1～5.0MPa, air speed ^-1

Embodiment 1

ZnO preparing carriers: under agitation to the Zn of 1M (NO ₃) ₂The NH of 1 dropping 1M in the aqueous solution ₄HCO ₃The aqueous solution filters out precipitation until PH=6.0, washing, and extrusion, 120 ℃ of bakings 12 hours under air then, 420 ℃ of roastings are 4 hours under air, are the embodiment carrier.The activity rating of ZnO carrier is with embodiment 2, and catalyst activity, selectivity ratios see Table 1.

Embodiment 2

0.05%Pd/ZnO preparation: with Pd (NO ₃) ₂Aqueous solution dipping embodiment 1 gained ZnO carries

Body, the Pd amount is 0.05% of carrier, and water-bath steam is fried and is done, and 120 ℃ were dried by the fire 12 hours, at air

The following 380 ℃ of roastings of atmosphere 3 hours.

Above-mentioned catalyst 1 gram is inserted in the stainless steel reactor of φ 10 * 1mm, used 10%H ₂/ N ₂150 ℃ of reduction half an hour, transfer to 150 ℃ of the reaction temperatures of setting, switch unstripped gas.This unstripped gas consists of: CO ₂0.08%, ethene 10.8%, ethane 0.11%, acetylene 7.36%, carbon monoxide 23%, methane 1.45%, air 0.45%, hydrogen balance.Form at different reaction time sample analysis tail gas.Catalyst activity, selectivity ratios see Table 1.Comparative Examples

0.05%Pd/ α-Al ₂O ₃Preparation of Catalyst: this catalyst does not belong to embodiments of the invention, only compares in contrast.The preparation method changes the ZnO carrier among the embodiment 2 in the 500 ℃ of air commercial α-Al of roasting after 3 hours with embodiment 2 ₂O ₃(BET surface area 34M ²/ g), the catalyst activity evaluation is with embodiment 2, and catalyst activity, selectivity ratios see Table 1.

Table 1: the influence of carrier (150 ℃, 30min. analyzes for 1500ml/g.H, normal pressure)

????Catal	Temperature (℃)	???Conv.	??S_％	???S_％	???S _Methane％	??S _C3+％
????Catal	Temperature (℃)	???Conv.	??S_％	???S_％	???S _Methane％	??S _C3+％	????ZnO	????150	????-	????-	?????-	?????-	Trace
??0.05％Pd/ZnO	????150	????100	???85.5	????1.1	????2.5	????10	????ZnO	????150	????-	????-	?????-	?????-	Trace
??0.05％Pd/ZnO	????150	????100	???85.5	????1.1	????2.5	????10	?0.05％Pd/Al ₂O ₃	????150	????100	????22	???55.5	????3.5	????19
????130	????100	????55	????26	????0.3	????42			????150	????100	????22	???55.5	????3.5	????19
????130	????100	????55	????26	????0.3	????42	????115		????63	????44	????0.0	????0.0	????55

Table 1 data show that simple ZnO carrier does not have hydrogenation activity at 150 ℃, have only the trace polymer to generate, and behind a small amount of Pd of load, have catalytic activity and selectivity preferably, by comparison, under identical load capacity and reaction condition, Pd-Al ₂O ₃Though catalytic activity is also higher, most acetylene become ethane, and also far above the Pd-ZnO catalyst, selectivity is relatively poor for polymerisation.Levy under 130 and 115 ℃, though ethylene selectivity has improved, polymerisation is aggravated simultaneously.

Claims

1, a kind of preparing ethylene by selective hydrogenation of acetylene catalyst, it is characterized in that this catalyst is is carrier with ZnO, ZnO contains the Zn compound from the salt that contains Zn, hydroxide and other, and it is binding agent that this carrier can contain the oxide of Si, Al, Ga or hydroxide sol and clay.

2, according to claim 1, it is characterized in that the activity of such catalysts component is Pd, Pd content is 0.01%～3% of vehicle weight, is generally 0.03%～0.5%, the suitableeest is 0.03%～0.2%.

3, according to claim 1 and 2, it is characterized in that the Pd/ZnO catalyst can add the oxide of alkali metal, alkaline-earth metal, rare earth element, hydroxide, carbonate and other inorganic salts, metal or the oxide and the inorganic salts that also can add transition elements Ag, Cu, Au, Sn, Pb, Cr, Ni, Co, Ga, Fe, Mo, or one or more mixing of above-mentioned additive are used.

4, according to claim 3, it is characterized in that these additives can add when the ZnO preparing carriers, or load again after the ZnO preparing carriers is finished, perhaps adopt two kinds of methods simultaneously.

5,, it is characterized in that catalyst and carrier can carry out heat pre-treatment in air, nitrogen or hydrogen atmosphere according to claim 1～4.

6, require 1～5 according to aforesaid right, it is characterized in that unstripped gas can contain 0～50% carbon monoxide, contains 0～99% ethene, also can contain carbon monoxide and ethene simultaneously or neither contain.

7, according to claim 6, it is characterized in that unstripped gas obtains by gaseous state or liquid hydrocarbon cracking or parpartial arithmetic, be that gaseous mixture and petroleum hydrocarbon cracking or parpartial arithmetic system ethylene process tail gas are produced in natural cyclone flame partial oxidation reactor waste heat oil spout as unstripped gas.