CS201736B1 - Process for producing ethylene oxide - Google Patents

Abstract

The invention relates to a process for producing ethylene oxide by direct oxidation of ethylene over ethylene oxide catalysts with circulating gas. The linear velocity of the stream or streams of gases and/or vapors circulating ethylene oxide in a quantity of 0.3 to 0 vol. is maintained from the outlet of the reactor or reactors to the ethylene oxide and water products from the reaction gases and/or vapors sink and/or absorber at a value of 0.5 to 25 m/β, while ensuring a uniform flow in the pipeline and the temperature of the ethylene pipeline is maintained at a value equal to or greater than by at most 30 °C than the temperature of the gases and/or vapors in the relevant pipeline. In the event of a drop in flow rate below 50% and/or an increase in pressure drop above 10% compared to the initial pressure drop from the outlet of the oxidation reactor or reactors and the inlet to the scrubber and/or absorber of ethylene oxide and by-products, the feedstock is stopped.

Description

201 736 i

The present invention solves the process of producing ethylene oxide by imparting ethylene oxidation to the ethylene oxide catalyst such that by adjusting the technology and equipment and significantly increasing the catalyst life, the working time, and the plant's production capacity, it achieves and maintains high production safety.

Ethylene Catalytic Oxidation Under Equilibrium

C2H4 + (3 - 2.5 s) 02 - with C2H4O + 2 (i - a) CO2 + 2 (i - s) HgO with £ being selectivity and 0 <a <1 on the surface of the atrium at the temperature of 180 to 270 ° C. The aim is to achieve as high a selectivity as possible for ethylene oxide, which can, inter alia, increase the permeation of the silver catalyst by small amounts of electronegative elements Cl, F, S, Se, P jTemkin. I., Kinetic and Catalyst 18, 544 (1977) and US Pat. 2 279 470 and 2 814 628} V. Brit. pat. Nos. 518,823 and 779,102J, Salim, Na, K, Li, Rb, Ce (U.S. Pat. No. 2,671,764) to Japanese Patent Application No. 9307/1957), as well as to Ba, Ca, and Ce (US). No. 2,825,701). In addition, we consider aa, especially the silver catalyst support, a portion of ethylene oxide may be isomerized to Twigg etaldehyde, Trans Faraday Soo. 42. 284 (19-6) J. In this process, the processes for the production of ethylene oxide are known, with the use of air or other oxygen-containing gas as the oxidizing agent, or oxygen itself. There are also known variants of the apparatus of R. P. Van Oesten, J of the Institute of Petro leum 46, No. 443, 347 (1960), Marahal Sittig, Petrol. Ref. 41, No. 6175 (1965), ProceseEngng, Oct. 1973, pp. 6-7, Pajda A., Pajda Ei Chemik, 24, 363 (1971), Considine, M, Dt Chemical and Prooea Technology, Enoyclopedia, 440-444. - Bili Book Co., New YorkJ. The reaction gases expelled from the oxidation reactor are generally led to the separation of ethylene oxide, leading to more products, with the non-converted starting materials generally re-circulating. Some equipment and technology variants try to use reaction heat to preheat raw materials or produce steam. However, the well-known and well-arranged procedures respect the fact that, as the main product, ie ethylene oxide, as well as the products such as acetaldehyde, water, are at a higher temperature, they are also well respected. subjected to a relatively short period of time, able to take or react with one another * to higher molecular products. These easily condense even at higher temperatures, prolonging contact, resp. the reaction time and, in addition, the oxidizing effect of non-converted oxygen may also be marked. Thus, ethylene oxide can react with water to form ethylene glycol and this, in addition to other ethylene oxide molecules, to polyglycols, aaldehyde, both to acetaldehyde, tetramaldehyde, but also to ootic acid, which in turn can be reacted with ethylene oxide and the like.

To this end, even higher olefins or paraffinic hydrocarbons in the high-purity, or in the auxiliaries, these particularly pronounced can be the precursor of the high molecular weight compounds which can be oxidized in the oxidizing environment to the solid coke products that I can hold the tracks. The gases generated by the oxidation can be fed into the reaction circuit, "poisoned" by the catalyst, reduced in life, efficiency, and selectivity. These and other problems and drawbacks of the device technology solve the present invention.

A process for the production of ethylene oxide by direct ethylene oxide oxidation with a gas, and preferably a mixture of acid, nitrogen and argon, optionally in the presence of carbon dioxide, methane, ethane and propane, on a silver-based catalyst, preferably in the presence of activators, usually on a support and (or in the mass) also the addition of ethylene oxidase inhibitors to carbon dioxide and water, at a temperature of 180 to 290 ° C, preferably 220 to 270 ° C, and a pressure of 0.8 to 4 MPa, preferably at a pressure of 1.2 to 2.5 MPaa, followed by isolation of ethylene oxide from the reaction product and a well-insulated and / or non-generating non-converted high performance raw material according to the present invention is such that the linearity of the streams or gas streams and / or vapor containing ethylene oxide from 0.3 to 4% by volume, preferably 0.6 to 2.5% by volume, is maintained from the reactor or reactor outlets to the washing machine and / or the ethylene absorber oxide and lead. products of reaction gases and / or vapors at a value of 0.5 to 25 m / s, except for the start-up and shut-down phases, preferably 8 to 18 m / s, while ensuring a uniform flow in the wall temperature walls the pipeline is maintained at a temperature equal to or less than 30 ° C as the temperature of the gases A / or vapor in the respective pipeline, in addition to achieving a drop in flow rate below 50 µl and / or increasing the pressure drop above 10 µg compared to the initial pressure drop the feedstock is stopped from the outlet of the oxidation reactor or reactors and the inlet to the washing machine and / or the ethylene oxide absorber and the bulk of the products. It should be noted that the linear outflow rate of the gases and / or the vapor of the reaction mixture exits the reactor, except for the start-up and shut-down phases, when there is little ethylene oxide in the reaction gases, is 0.5 to 25 m / s, preferably 8 up to 18 m / s. If it is too low, there is little utilization of the equipment (pipe) and deposits can be deposited, the reaction time of the reactants of the components can be increased with the oxygen and if it is too high, it is used only as a heat source, the effectiveness of the washer and / or absorber is reduced. Further, it is necessary to maintain the required temperature of the pipe walls so that the ethylene oxide-containing gas streams can either have the same temperature as the reaction gas or less than 30 ° C. It is mainly about creating conditions that the temperature is not lower than the dew-lower volatile components of the reaction gases. To keep the gas and / or the ethylene oxide-containing vapor down on the polluting route, the gasses and vapors of the gas do not drop to zero in the "dead" facility where condensation of gases and vapors can occur, and consequently the subsequent reactions. , condensation and oxidation agents such that they absorb liquid, semi-solid, elastic to solid products. These, in addition to generating generated gases and a pair, can increase their routes. If the above conditions are not met, some of the main and secondary products are separated before the ethylene oxide and the products in the washing machine and / or the absorber are separated. Due to the full safety of production, especially in the case of particularly long production cycles, it is advisable to control the possible clogging of the reaction gas and / or the vapors emitted from the reactor, or the measured flow rate, or simply the pressure gradient, by other reliable procedures. An advantage of the method of the present invention is the operational reliability of the device, the increased safety, the long catalyst life, the high ethylene conversion and the selectivity of 201 736 3 to ethylone oxide, less sensitivity to eventually reduced purity of the recombinant components. Further advantages, as well as details of the device design, are shown in the example figure

Pipe 11 (VI. Fig.) Feeds ethylene through the feed mixer 6 and contains oxygen-containing gas (substantially pure oxygen) via a feed mixer 10. From this point, the mixed gases are fed into the oxidation tube reactor 8 and preheated, which comprises in a tempered tube, a silver catalyst in a mass of 8.9% by weight. silver with activators, at a pressure of 2 MPa with a volumetric rake of 2,700 h -1 and a heat of 243 ° C. The reaction gases and / or vapors containing ethylene oxide as the main reaction product at a temperature of 243 ° C are passed through line 42 which has no "dead" sites, thus having virtually no flow sites and passing through a heat exchanger 2, where they transfer a portion of the heat while cooling to a temperature of 1 < &lt; 8 < 0 &gt; C &lt; 8 &gt; C &lt; / RTI &gt; and / or a pair, respectively. absorbing β, especially ethylene oxide. In the washing machine, respectively. the absorber 4 provided with the scrubbing medium inlet 21 is washed with ethylene oxide with a portion of the incoming gases and / or vapor at a temperature of 20 to 28 ° C. Next, the outlet 15, in addition to the ethylene oxide solution and the isolating agent, and the mixture of ethylene oxide-free gases is added to the washing machine head. the absorber via line 16 through the heat exchanger 6 and the conduit 17 for suction of the circulation compressor 2, whereby a portion of the gases is discharged from the reaction circuit by the removal of the off-gas 18. From the discharge of the compressor 2, the gas outlet at a temperature of about 33 ° C exits the washing machine outlet 24 and / or the carbon dioxide abeorber 8 and therefrom the heat exchanger 6 to the mixer. and from it together with fresh ethylene to mixer 10.lca &amp; previously, inert gases are added to the circuit via the inlet 20 under said conditions.

From the mixer 10, the gas mixture, together with the fresh starting materials, is fed to the circuit via lines 13 and 12 via line 13 to an oxidation tube reactor provided with a preheater. The porosity of the device is continuously 10 months and the average of 110 β ethylene oxide per dm ^ of catalyst per hour. Example 2

Progress aa a &amp; and the apparatus set forth in Example 1, only. with the difference that a portion of the reaction gases and / or vapors exiting the oxidation tube reactor 6 through the coil 14 is additionally divided into 3 to one to two branches 22 to 28 (° br) into the heat exchanger £ or up to scrubbing machine so that the olefin coalesces the reaction gases and / or

Claims (1)

201,736 pair and the content of the main reaction product - ethylene oxide, falls below 0.2 m / s and for a short time at least 1 branch to zero. During 6 months, 100 to 110 g of ethylene oxide / dole per 1 major of catalyst per hour is produced, but after 9 months, uneven production, temperature fluctuations in the reactor, production loss to 40 g of ethylene oxide per dm @ 2 of catalyst per hour can occur. and to substantially reduce catalyst activity. This cannot be significantly increased by the known successive ones! recovery and neither raising the temperature to 265 ° C and adjusting the reaction gas pipe and / or pair 14 of Example 1, maximum production of only 83 g of ethylene oxide per 1 d catalyst per hour is achieved, while the ethylene oxidation selectivity is reduced by approx. Branches in which the linear curvature decreases below 0.2 m / s and short-term to zero are gradually sequestered by condensation and oxidation products, in the extreme case a mixture of stiff and partially elastic and plastic condensation agents is formed. oxidizing products of this composition: ash 0.1% by weight; mainly formed from iron, calcium, media, manganese, silicon and magnesium compounds; % 57.2 wt. and hydrogen of 5.6 wt.%, the infrared absorption spectrum indicates the presence of * -OH, CsO 2, C-O-O, 8 suggests the presence of ethylene oxide polyaddition products, mainly acid, respectively. also aldols and aldehydes, as well as oxidized polyglycols. SUMMARY OF THE INVENTION A process for the preparation of ethylene oxide by direct oxidation of ethylene with oxygen-containing gas, preferably a mixture of oxygen, nitrogen and argon, optionally in the presence of carbon dioxide, methane, ethane and propane, on silver-based catalysts, preferably in the presence of activators, usually on the carrier and / or in the mass, usually also with the addition of ethylene oxidation inhibitors to carbon dioxide and water, at a temperature of 180 to 290 ° C, preferably 220 to 270 ° C, and a pressure of 0.8 to 4 MPa, and preferably at a pressure of 1 2 to 2.5 MPaa by subsequent isolation of the ethylene oxide from the reaction product and, as a rule, isolation and recovery of the non-converted starting materials, characterized in that the linearity of the stream or gas streams and / or vapors contains about 10 to about 4% by volume of ethylene glycol. , preferably 0.6 to 2.5% by volume, is maintained from the outlet of the reactor or reactor to ethylene oxide and by-products of the reaction gas / vapor at values of 0,5 0.5 to 25 m / s, except for the start-up and shut-down phases of the process, preferably 8 to 18 m / s, ensuring a uniform flow in the pipeline and keeping the piping wall temperature at a value equal to or less than 30 ° C, such as the temperature of the gases and / or vapors in the pipework, with an increase in flow rate below 50 ° and / or an increase in pressure drop of more than 10% compared to the initial pressure drop from the output oxidation reactor or reactors and inlet Into the washing machine and / or the ethylene oxide absorber of the products, the feedstock is stopped. 1 výterea