CN1068319C - Pressure triphase-series ethylene oxide synthesizing process - Google Patents

Abstract

The present invention relates to a gas-liquid-solid three-phase synthesis epoxy ethane technique. A three-phase bed reactor with a fine particle catalyzer is used, and silicon oil with high boiling point and oxidation resistance is used as a liquid phase medium. Raw materials of ethene and oxygen generate epoxy ethane under the action of a silver catalyst. The technique has the characteristic of obviously improving catalyst selectivity and can be used for industrial production.

Description

Pressure triphase-series ethylene oxide synthesizing process

Gu the present invention relates to gas-liquid-three-phase bed synthesize epoxyethane technology.

Oxyethane is important organic raw material, is in the product at ethene, and its output is only second to polyethylene.The classical way of ethylene oxide production---chlorohydrination is because chlorine consumption is big, environmental pollution seriously is eliminated.Almost produce with the oxidation of ethylene method entirely in the world at present.Oxidation style is produced and is divided into air method and two kinds of technologies of oxygen method again.The oxygen method is compared with the air method, selectivity height, investment less (enterprise that has particularly possessed air separation plant), equipment capacity is big, process cost is low advantage, the most oxygen method technologies that adopt of therefore newly-built ethylene oxide device.

The oxygen method is produced oxyethane, and the ethene unit consumption constitutes about 70% of oxyethane cost approximately.For the bulk raw material that has a large capacity and a wide range, reducing the ethene unit consumption has immeasurable economic benefit.Oxidation style, no matter be that oxygen method or air method all adopt silver catalyst, the chemical constitution and the physical properties of catalyzer are basic identical.By the level of present industrial application silver catalyst, unit of the every raising of selectivity with regard to ethylene oxide production ability (10,000 tons/year), can consume 104 tons of ethene less, or increases production 130 tons in oxyethane.Therefore, all attach great importance to updating of catalyzer both at home and abroad, be devoted to develop the catalyzer of selectivity height, good stability.

In order to improve the selectivity of silver catalyst, some patent reports improvement project and result of study separately, wherein great majority are to adopt the measure of adding various promotors.The promotor that is added mainly is all cpds of basic metal, alkaline-earth metal, rare earth metal and compound thereof and VIII family element.Suitably select one or more above-mentioned element or compounds, and determine activity, selectivity and work-ing life that optimum addition and corresponding addition means thereof can improve silver catalyst.Same selectivity and stability in order to improve silver catalyst, people have also done more improvement to the technology of oxyethane, cooling system as reactor changes water cooling into, replace nitrogen as causing steady agent with methane, use a small amount of inhibitor such as ethylene dichloride to improve selectivity of oxyethane or the like, but because the reaction process that uses was gas-solid phase external cooling tubular fixed-bed reactor in the past, unavoidably there is axial temperature rise in beds, thereby increased the deep oxidation side reaction, reduced selectivity, as document US 4061659, introduced the improvement of reacting ethylene oxide technology and reactor among the EP0130807A2, because it all adopts former beaded catalyst gas-solid phase shell and tube reactor technology, thus temperature rise in beds axial temperature rise and the catalyst pellets can not be avoided, thus influence its selectivity of catalyst.

The objective of the invention is to have temperature rise in axial temperature rise and the catalyst pellets in order to overcome in the catalyst reactor bed that exists in the above-mentioned document, thereby influence the shortcoming of its catalyst selectivity, Gu a kind of gas-liquid-three-phase synthesize epoxyethane novel process is provided, and this technology has the characteristics of the catalyst selectivity of significantly improving.

The objective of the invention is to realize: a kind of ethylene oxide synthesizing process by following technical scheme:

A) be reaction raw materials with ethene and oxygen, unstripped gas contacts with fine particle silver catalyst in being suspended in the liquid phase thermal barrier, is 170～240 ℃ in temperature, and pressure is under 1.8～2.2MPa condition catalyzed reaction to take place;

B) silver content of silver catalyst is 5～30% by weight percentage, and the granules of catalyst diameter is 20～200 orders;

C) thermal barrier adopts under the normal pressure boiling point greater than liquid phase medium 200 ℃, antioxidant property;

D) reactor adopts three-phase bed reactor.

In the technique scheme, the liquid phase medium preferred version is a silicone oil; For improving catalyst selectivity, can add the inhibitor ethylene dichloride in the unstripped gas, its consumption is 0.2～0.4ppm, the preferred version of its reactor is a slurry-phase reactor.

Gu key of the present invention is to have adopted gas-liquid-three-phase bed reaction technique, for guaranteeing that catalyzer can be suspended in the liquid phase thermal barrier, to eliminate catalyst pellets internal diffusion and temperature rise, therefore the granules of catalyst diameter can not be excessive, should be about 20～200 orders, the medium of thermal barrier employing simultaneously is also quite important, and it must possess high boiling point, antioxidant property is good, to prevent decomposition or the oxidation of liquid phase medium under hot conditions.

In the present invention, Gu owing to adopted gas-liquid-three-phase slurry bed reaction technique, Gu the mass transfer process of reaction is carried out between gas-liquid-three-phase, and on the active internal surface of solid phase silver catalyst, react, because the temperature of liquid phase thermal barrier is easy to control, strengthened heat transfer process in addition.The thermal conduction of this technology and better heat stability; temperature of reaction is in isothermal; axial temperature rise and the interior temperature rise of catalyst pellets in the silver catalyst bed have been eliminated; suppressed the side reaction of deep oxidation in the oxyethane building-up process to greatest extent; thereby improved selectivity; usually to select performance to improve about about 3% for oxyethane, obtained effect preferably.

The present invention is further elaborated below by embodiment.[embodiment 1～10]

Gu in gas-liquid-triphase slurry bed reactor, the liquid phase thermal barrier is a silicone oil, its consumption is 200 milliliters, catalyzer is that silver content is the silver catalyst of 13% (weight), catalyst grain size 150 orders, catalyst levels 14 grams, its raw material feed composition and response situation are listed in table 1, in, wherein adding inhibitor ethylene dichloride 3ppm in the reactor feed gas, beds is in isothermal.

Table 1 oxyethane synthesizes gas-liquid-solid three-phase slurry bed data

Embodiment	Pressure (table) (MPa)	Temperature ℃	Inlet is formed (%)			Air speed NL/ kgcat.h	(%) formed in outlet				Selectivity S%
												C 2H 4	O 2	CO 2	C 2H 4	O 2	CO 2	EO
			1	2.01	221.7		28.14	7.15	8.52	5791.2									27.04	5.09	9.83	1.51	74.73
2	2.01	204.8				28.14					7.15	8.52	6207.9	27.29	5.83	9.31	1.25	81.15
			3	2.01	194.1		28.14	7.15	8.52	5978.4									27.42	6.17	9.07	1.10	85.18
4	2.01	182.4				28.14					7.15	8.52	5914.2	27.51	6.38	8.94	0.99	88.11
			5	2.03	225.9		22.74	6.91	7.04	5829.4									22.74	5.27	8.03	1.24	75.64
6	2.03	208.3				22.74					6.91	7.04	5802.4	22.88	5.69	7.71	1.15	81.76
			7	2.03	192.4		22.74	6.91	7.04	5596.0									23.11	6.13	7.46	0.87	84.85
8	2.03	181.3				22.74					6.91	7.04	6051.2	23.17	6.27	7.36	0.81	88.12
			9	2.03	180.8		22.74	6.91	7.04	6440.5									23.22	6.33	7.33	0.74	88.34
10	2.04	181.2				60.52					8.72	7.47	5734.0	59.50	7.14	9.27	1.53	87.87

[comparative example 1～9]

In gas-solid phase tubular fixed-bed reactor, catalyzer is that silver content is the silver catalyst of 13% (weight), catalyzer is an annulated column shape, be of a size of external diameter 6.97mm * internal diameter 2.22mm * high 5.91mm, catalyst levels is 24 grams, and its raw material feed composition and response situation are listed in the table 2, wherein adds inhibitor ethylene dichloride 3ppm in the reactor feed gas, because beds is anisothermal, so the temperature data in the following table 2 is the beds medium temperature.The tubular fixed-bed data of table 2 oxyethane synthetic gas-solid phase

Embodiment	Pressure (table) (MPa)	Temperature ℃	Population composition (%)			Air speed NL/ kgcat.h	(%) formed in outlet				Selectivity S%
												C 2H 4	O 2	CO 2	C 2H 4	O 2	CO 2	EO
			1	2.01	218.4		28.14	7.15	8.52	12214.1		26.50	4.41	10.13	1.54	68.51
2	2.01	205.7	28.14	7.15	8.52	10878.0	27.04	5.59	9.37	1.09	74.63
3	2.01	194.5	28.14	7.15	8.52	7184.0	27.08	5.85	9.17	1.09	79.64
4	2.01	180.2	28.14	7.15	8.52	7194.8	27.11	6.04	9.03	1.09	83.07
5	2.03	226.1	22.74	6.91	7.04	7289.2	22.37	4.79	8.24	1.24	69.70
6	2.03	208.4	22.74	6.91	7.04	7623.4	22.51	5.30	7.87	1.10	76.43
7	2.03	192.8	22.74	6.91	7.04	11833.4	22.89	5.98	7.47	0.86	82.23
8	2.03	182.8	22.74	6.91	7.04	7093.2	22.93	6.06	7.41	0.84	84.02
9	2.03	181.8	22.74	6.91	7.04	11347.2	23.01	6.17	7.36	0.76	84.82

Claims (3)

1, a kind of ethylene oxide synthesizing process is characterized in that:

A) be reaction raw materials with ethene and oxygen, unstripped gas contacts with fine particle silver catalyst in being suspended in the liquid phase thermal barrier, is 170～240 ℃ in temperature, and pressure is under 1.8～2.2MPa condition catalyzed reaction to take place;

B) silver content of silver catalyst is 5～30% by weight percentage, and the granules of catalyst diameter is 20～200 orders;

C) thermal barrier adopts under the normal pressure boiling point greater than liquid phase medium 200 ℃, antioxidant property;

D) reactor adopts three-phase bed reactor.

2, ethylene oxide synthesizing process according to claim 1 is characterized in that three-phase bed reactor is a slurry bed reactor.

3, ethylene oxide synthesizing process according to claim 1 is characterized in that liquid phase medium is a silicone oil.