The single-stage method of oxychloride ethylene in a fixed layer

 

(57) Abstract:

The described method of oxychloride ethylene to obtain 1,2-dichloroethane involves reacting an excess of ethylene with chlorine source and a source of oxygen in a reactor with a fixed layer to oxychloride in the presence of a catalyst based on copper chloride on the carrier. The reagents are fed to the input of a separate reactor and the ethylene is in a molar excess relative to chlorine from 200 to 700%. The technical result is to simplify the process and achieve high selectivity for ethylene along with the utilization of HCl over 99%. 7 C.p. f-crystals.

The present invention relates to oxichloride ethylene in a reactor system with a fixed layer, which contains a separate reactor for the production of chlorinated hydrocarbons, in particular, 1,2-dichloroethane (EDC = EMF).

It is well known that hydrocarbons such as ethylene, can be gloriavale through their interaction with hydrogen chloride and a gas containing elemental oxygen, in particular air or oxygen-enriched air, in the presence of a catalyst and at elevated temperatures and pressures to obtain chlorinated hydrocarbons such as EMF. The reaction can wypolnjatj vooruzhennym layer, in which the mixture of gaseous reactants in contact with a fluidized bed of powdered catalyst. The second is a technology that uses a reactor with a fixed layer, in which the gaseous reactants pass over a fixed catalyst inside the reactor.

The fluidized bed reactor have many disadvantages, such as possible viscosity of the powder catalyst, instability, limited selectivity due to the overpressure of gas and solid catalyst particles mixed in the reactor, the heat loss due to damage to the seal, radiator and speed limits reagents caused by the need to avoid losses of catalyst leaching from the reactor.

A technology that uses a reactor with a fixed layer, developed to resolve these problems (see U.S. patents NN 3892816 and 4123467).

Although the reactor with a fixed layer eliminates many of the problems associated with the reactor system with a fluidized bed, there are a lot of new problems. The main problem in the reactor with a fixed layer is the difficulty of transferring heat released during the exothermic reaction oxychloride, from the reactor to significant others is respect. In addition, because it can be unsafe to have the oxygen concentration in the mixture fed to the reactor, above 8% for reasons of Flammability, the reaction is performed in two or more successive stages (usually three), so that the ethylene is introduced into the first reactor, while HCl and oxygen is supplied between the reactors. Unreacted ethylene together with some inert gases back into the first reactor.

In a further effort to reduce the sphere of influence of hot spots, etc. well-known attempt to modify the profile of the activity of the catalyst inside the reactor with a fixed layer so that the activity increased in the direction of flow. For example, see the application for Europatent N 0146925. However, the prior art suggests that even when using a shaped catalyst, it is necessary to apply multireactor system.

The authors present a new way catalytic oxychloride ethylene, which use the same reactor with a fixed layer. However, eliminates hot-spots and achieve high selectivity for ethylene along with the utilization of HCl over 99%.

According to the first aspect of the invention Ave is Yong, the source of chlorine and a source of oxygen in oxichloride reactor with a fixed layer in the presence of a catalyst, characterized in that the use of one reactor, and ethylene is present in a large molar excess with respect to chlorine.

Preferably, the source of chloride is HCl. Preferably, ethylene is injected with an excess of 200-700% of the molar equivalent relative to the stoichiometric amount of HCl to get high partial pressure of ethylene.

The source of oxygen may be pure oxygen or oxygen-enriched gas. Oxygen is supplied preferably with a molar excess of up to 15%, more preferably between 2 and 8% compared to HCl.

Large excess presence of ethylene is designed to increase the selectivity of the reaction and also acts as a heat flow, using its high specific heat. Unreacted ethylene is preferably disposed and return back to the reactor or in other processes that require ethylene, such as direct chlorination reaction.

The composition of the recycle gas reaches equilibrium based mainly on the speed of combustion, the amount of inert to hepatica between 10% and 90%. As a consequence, the actual excess ethylene will depend on its concentration in the exhaust recycle gas and the speed of the recycle stream.

Generally an excess of ethylene relative to its stoichiometric requirements, as it is dictated by the amount of HCl can be expressed in terms of a percentage in accordance with the formula

< / BR>
where 100 is the stoichiometric requirement and where

< / BR>
and

< / BR>
where % Q2the inlet oxygen inlet in the reactor;

% O2recycling. oxygen in the recycle stream;

The symbols represent the following:

Q1 - mol/hour of the ethylene feedstock;

Q2 - mol/HR of recycle ethylene;

Q3 - mol/h of HCl;

Q4 - mol/h in just recycle the product;

Q5 - mol/h of the feed ethylene;

Q6 - mol/hour of the supplied inert gas;

Q7 - mol/hour of supplied oxygen;

Q8 - mol/hour, the total number of initial reagents.

For regulating the oxygen concentration at the inlet of the reactor and thereby the temperature of the hot spots, you can use the regulation of the flow rate of recycle gas. In the conditions of temperature and pressure existing at the inlet of the reactor, when the oxygen concentration is within 8%, has mesio preferably be maintained between 5 and 6% vol., since the use of higher concentrations may result in increased temperature hot spots in the catalytic layer.

Typically, the temperature of the hot spots can be about 230-280oC, depending on many factors, including the diameter of the reactor.

The reactor used according to the method of the invention is a tubular reactor. It consists predominantly collected in a tube bundle within a single housing with a cooling medium. The inner diameter of each pipe is preferably from 20 to 40 millimeters. The diameters of less than 20 millimeters unacceptable, because to obtain sufficient bandwidth for materials requires an excessive number of tubes, while the diameters of more than 40 millimeters lead to too high temperatures of the hot spots inside the catalytic layer.

The preferred length of the reactor ranges from 3.5 to 8 meters. Length less than 3.5 meters leads to a too short residence time of the reactants, and so either to a low conversion of reactants or low specific bandwidth; in the length of more than 8 meters, there is no need, in order to obtain high conversion of HCl and the diamonds are located in a different way. For example, the reactor can be simply filled with a catalyst in the usual manner, without the use of profiled the location of the catalyst. Alternatively you can use a simple type of boot, in which the catalyst is loaded into two layers, the first with a low catalyst, or a diluted catalyst (see U.S. patent N 4123467) - to eliminate hot spots, and the second with a more active or a more concentrated catalyst to increase the reaction rate. In addition to this more complex view of the boot consists of a sequence of several layers of catalyst with increased activity (or concentration) from the first to the last layer. Selecting the appropriate type of loading of the catalyst will depend on the maximum temperature of the hot spots as the diameter and the length of the tubular reactor, and from the design capacity.

In all cases it is preferable to fill the last part of the reactor high activity catalyst, such as is used in the third reactor in the three-stage process of oxychloride.

Catalysts for use in the present invention are known in the art and are Catalunia, silica gel, aluminum silicate, etc., represent the media. Material carriers can be present in the form of balls, cubes, hollow cylinders, cylindrical pellets, lumpy pellets and other forms.

In addition to the copper chloride catalyst may also include promoters, such as the chlorides of potassium, magnesium, sodium, lithium, calcium, cerium and cesium, to improve the selectivity by EMF. Profile the activity of the catalyst in the catalytic layer can be designed in such a way as to obtain the conversion of HCl over 98% in the area from 70 to 80% of the distance along the catalytic layer. The remaining 20 to 30% of the catalytic layer will perform the function of the finisher so that the reaction generally produces high conversion, even if the first part of the catalytic layer will lose over time activity.

The reagents are preferably pre-heated to temperatures of 100 to 200oC. the Pressure in the reaction may be at the level of up to 20 bar excessive, and the preferred range gauge pressure ranges from 4 to 7 bar.

Further, solely for the purpose of explanation, will be followed by the description of the invention the following examples.

Example 1
oC and a gauge pressure of 18 bar. The pressure in the reactor on line effluent is regulated by a pneumatic valve.

The reagents are pre-warmed in heat exchangers at a gauge pressure of 18 bar, then ethylene, HCl and nitrogen were mixed together, and oxygen was added into the mixer, where the velocity of the gases was higher than the velocity of propagation of combustion of ethylene. The used catalyst was a conventional industrial catalyst for normal oxygen three-stage process with a fixed layer containing hollow cylinders containing copper chloride and potassium, are placed so that the amount of copper from the entrance to the exit of the reactor was changed from 24 to 60 grams/liter. The amount of the catalytic layer was 2.6 liters. In this reactor was introduced a mixture of 223,1 mol/hour of ethylene, 66,8 mol/h of HCl, 17.5 mol/hour of oxygen and 18 mol/h of nitrogen. Excess oxygen was 4.8%.

Nitrogen was used for stimulation of inert gases in the recycle gas of 90% ethylene and 10% inert gases. Excessive inlet pressure was 5.1 bar, and the output is 3.5 bar. The temperature of the cooling casing supported at 210oC. output stream containing a mixture of ethylene, oxygen, HCl, nitrogen, EDS, water, COxand by-products, were analyzed and the results were:

Conversion of the oxygen in the raw EMF - 94.7% of

Conversion of HCl in the raw EMF - 99.4% of

The output EMF is 32.8 mol/hour

The selectivity of ethylene to COx0.6% of the molar.

The selectivity of ethylene by ECl - 0,24% molar.

The selectivity of ethylene on EMF - 98,66% molar.

The selectivity of ethylene to chloral - 0.15% of the molar.

The selectivity of ethylene on pollution - 0.35% of the molar.

The point of overheating - 233oC

Example 2

This example was performed in the same reactor and Catholic scheme, as in example 1. Gave a mixture of 169 mol/hour of ethylene, 71,5 mol/h of HCl, to 19.5 mol/hour of oxygen and 65 mol/h of nitrogen. Excess oxygen was 9%. Recycle composition consisted of 70% ethylene, 30% by volume of inert gases. The outlet pressure was 7.2 bar is redundant. The temperature in the cooling jacket was 210oC.

The results were:

Conversion of the oxygen in the raw EMF - 90,8%

Conversion of HCl in cheese Edst ethylene by ECl - 0,17% molar.

The selectivity of ethylene to chloral - 0.20% molar.

The selectivity of ethylene on EMF - 98,92% molar.

The selectivity of ethylene on pollution - 0.37% of the molar.

The point of overheating - 277oC

Example 3

This example was performed in the same reactor and catalyst pattern as in examples 1 and 2. Gave a mixture of 267,55 mol/hour of ethylene, 93,45 mol/h of HCl, 25 mol/h of oxygen, 50 mol/h of nitrogen. Excess oxygen was 7%. Recycle composition: 80% ethylene, 20% by volume of inert gases.

Excessive outlet pressure was 3.2 bar, and at the entrance of 6.6 bar. The temperature in the cooling jacket was 210oC.

The results were:

Conversion of the oxygen in the raw EMF - 90,9%

Conversion of HCl in the raw EMF - 99%

The output EMF - 46.2 mol/hour

The selectivity of ethylene to COx0.13% for the molar.

The selectivity of ethylene by ECl - 0.25% molar.

The effectiveness of ethylene on chloral - 0,10% molar.

The selectivity of ethylene on EMF - 99,12% molar.

The selectivity of ethylene on pollution - 0,40% molar.

The point of overheating - 233oC

Example 4

Was installed in the reactor, consisting of one Nickel tubes with outer diamino industrial reactor, inside pocket with outer diameter 6 mm, containing 4 sliding thermocouple. Regulation of temperature, pressure and flow of the reagents were the same as in example 1. The amount of the catalytic layer was 1.8 liters. The used catalyst was the same type as in the other examples. The copper content ranged from 24 to 46 grams/liter.

The feed mixture consisted of 272 mol/hour of ethylene, 97.5 mol/h of HCl, 26.8 mol/hour of oxygen and 24.6 mol/h of nitrogen. The excess of oxygen was 10%. Recycle composition consisted of 90% ethylene and 10% inert gases. Excessive outlet pressure was 5.5 bar, and pressure drop - 0,55 bar.

The results were:

Conversion of the oxygen in the raw EMF - 89%

Conversion of HCl in the raw EMF - 98%

The output EMF - 47,6 mol/hour

The selectivity of ethylene to COx0.13% for the molar.

The selectivity of ethylene by ECl - 0.20% molar.

The selectivity of ethylene on EMF - 99,10% molar.

The selectivity of ethylene to chloral - 0.15% of the molar.

The selectivity of ethylene on pollution - 0,42% molar.

The point of overheating - 258oC

Example 5

In the same reactor and Catholic scheme, as in example 4, gave a mixture of 214,2 mol/h) is the composition consisted of 90% ethylene and 10% inert gases. Excessive outlet pressure was 5.5 bar and a pressure drop of 0.5 bar.

The results were:

The conversion of oxygen - 87,1%

Conversion of HCl at 99.1%

The output EMF - 42 mol/hour

The selectivity of ethylene to COx- 0,30% molar.

The selectivity of ethylene by ECl - 0.20% molar.

The selectivity of ethylene on EMF - 98,50% molar.

The selectivity of ethylene to chloral - 0.20% molar.

The selectivity of ethylene on pollution - 0,80% molar.

The point of overheating - 270oC

Example 6

Using the same reactor as in examples 4 and 5, but with the same type of loading of the catalyst, as in the first stage, three-stage process using a catalyst containing 26 grams/liter copper, and about 12 grams/liter of potassium in the first 3/5 of the reactor and 40 grams per liter of copper and 18 grams per liter of potassium in the rest part, carried out the reaction in a mixture of 231 mol/hour of ethylene, 18 mol/h of oxygen, 64.8 mol/h of HCl and 42 mol/h of nitrogen. Excessive outlet pressure was 5.5 bar, and the drop in pressure of 0.45 bar.

The results were:

Conversion of the oxygen in the raw EMF and 88.5%

Conversion of HCl in the raw EMF of 97.8%

The output EMF - 31,7 mol/hour

The selectivity of ethylene to COx- 0,10% molar.ptx2">

Selectivity for chloral - 0,10% molar.

The selectivity of ethylene on pollution - 0,30% molar.

The point of overheating - 255oCE

1. The way the ethylene oxychlorination process for producing 1,2-dichloroethane, including the interaction of an excess of ethylene with chlorine source and a source of oxygen in the reactor for the oxychlorination process with a fixed bed of the catalyst based on copper chloride on a carrier, characterized in that the reagents are fed to the input of a separate reactor and the ethylene is in a molar excess relative to chlorine from 200 to 700%.

2. The method according to p. 1, wherein the source of chloride is HCl.

3. The method according to p. 1 or 2, characterized in that the catalyst comprises, in addition, the chlorides of potassium, magnesium, cesium, sodium, lithium, calcium or cerium.

4. The method according to any of paragraphs.1-3, characterized in that the oxygen is present in a molar excess of up to 15% compared to chlorine.

5. The method according to p. 4, characterized in that the molar excess of oxygen is in the range from 2 to 8%.

6. The method according to any of paragraphs.1-5, characterized in that the profile of the catalyst activity increases in the direction of flow of the reactants.

7. The method according to any of paragraphs.1-6, otlichuy the inu from 3.5 to 8.5 m

8. The method according to any of paragraphs.1-7, characterized in that the implement recycling of purged gases.

 

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EFFECT: reduced expenses due to using production waste.

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