DE865893C - Process for the production of hydrocarbon mixtures - Google Patents

Description

Process for the preparation of hydrocarbon mixtures The invention relates to a process for the production of hydrocarbon mixtures from hydrogen and carbon monoxide using an iron catalyst, which is a relatively high content of gaseous olefins with 2 to q. Have carbon atoms.

The production of hydrocarbons through catalytic hydrogenation of carbon monoxide with hydrogen has been used successfully in industry for a long time carried out. Most of the previous researchers developed the procedure with the aim of to obtain a high yield of liquid products that are within the gasoline range boil to supplement the build-up of these petroleum fuels. Others studied the reaction to get to know the conditions under which methane forms the hydrogenation product and their determination to increase the calorific value of gaseous fuels was used.

The method of this invention also relates to synthesis of olefins with 2 to q. Carbon atoms. Hydrocarbon fractions of these Kind form the raw material that makes up the bulk of the industrial aliphatic Connections is established. A synthetic base product for these substances, that is the current starting products, which are predominantly made from natural gas concentrates and refined gases, augmented, would be very desirable.

In the course of the experiments in which mixtures of hydrogen and carbon monoxide were passed over iron catalysts, the known important reaction factors, such as temperature, pressure, ratio of the reactants, etc., were investigated and found that they had no significant influence on the amount of hydrocarbons with 2 to 4 carbon atoms (hereinafter referred to as C2 to C4 fraction). For example, the yield of the C2 to C4 fraction remained within a temperature range of. 22o to 32o ° with about 25 to 40% of the hydrocarbons formed fairly constant. However, it was found that the content of the liquid fraction (C5 and higher hydrocarbons) decreased as the temperature increased and was accompanied by a corresponding increase in methane formation, the amount of the C2 to C4 fractions remaining approximately the same. The percentage distribution of the hydrocarbons based on their carbon number, as used here, corresponds to the percentage distribution of the carbon atoms in the hydrocarbons. For example, in a gas mixture whose components are in a ratio of 2 molecules methane-C H4 (z carbon atoms per molecule), 1 molecule ethane-C2H6 (2 carbon atoms per molecule) and 2 molecules propane-C3 H $ (3 carbon atoms per molecule) ) are related to each other, the total = o carbon atoms in 5 molecules of the mixture. The percentage composition of the hydrocarbons based on their carbon number is calculated as follows According to the invention, the process for the preparation of hydrocarbon mixtures which have a relatively high content of normally gaseous olefins with 2 to 4 carbon atoms consists of the reaction of .Kohlenmonoxyd with hydrogen in the presence of an iron catalyst, this catalyst being used during the synthesis with chlorine, Bromine or iodine containing substances is brought into contact. The halogens or hydrogen halides may be introduced into the reaction system as they are or in the form of compounds which give off those under the reaction conditions. The organic compounds of chlorine, bromine and iodine may be mentioned as compounds which are able to give off halogen or hydrogen halides, since such organic halides decompose under the reaction conditions. When the terms halogen or halide are used here later, chlorine, bromine, iodine or the corresponding halides are meant. Fluorine and fluorides are excluded as tests have shown that they are not effective retarders. If the synthetic gas, composed of carbon monoxide and hydrogen, is passed over a halogen-delayed iron catalyst at a reaction temperature of zoo to 45o °, the C2 to C4 fraction usually forms about half of the resulting hydrocarbons, and the olefin content of this C. to Cr fraction is approximately twice the C2 to C4 fractions that arise with non-delayed catalysts.

The effect of the selective retardation of the iron catalyst on the composition of the product is illustrated by the following table at reaction temperatures of 22o to 32o °: Percentage composition of hydrocarbons Carbon based hydrocarbons with untreated with delayed Catalysts 1 catalysts CH 4 ............. = o to 30 = o to 25 C2 to C4 Olefuie ... = o to 2o 25 to 45 C2 to C4 paraffins. = o to 30 = o to 25 C5 and higher ..... 3o to 6o 2o to 5o Total Cz- to C4 Fraction ........ 25 to 40 4o to 65 From the table above it can be seen that the olefin content of the C2 to C4 fractions formed is significantly increased in the case of delayed catalysts. It has also been found that the olefin content of the liquid fraction obtained with delayed catalysts is also high.

The delay of the catalyst also significantly reduces the amount of carbon dioxide produced in the reaction. A low level of carbon dioxide in the gas produced is an advantage since the removal of this compound from the rest of the produce creates additional labor costs. The course of the reaction with the delayed catalysts can thus be represented essentially as follows: CO + 2H2 @ - (C H2) + Ha0 (i) The corresponding reaction (2), which produces carbon dioxide, is suppressed here: 2 CO + H2 -> - (CH2) + C02 (2) Typically, delayed catalysts are less effective than pre-delay catalysts and the conversion of synthesis gases to total hydrocarbons is consequently less when using delayed catalysts when the other conditions are the same. However, the percentage conversion of the synthesis gas into hydrocarbons can be increased by increasing the reaction temperature up to the temperature suitable for the catalyst used. The percentage conversion as described herein is illustrated by the following equation V, = volume of the converted CO + H2, V2 = total volume of the gas supplied. If z. B. the total volume of the gas supplied contains 50 moles of carbon monoxide and 50 moles of hydrogen and the resulting gas contains 3o moles of carbon monoxide and 2o moles of hydrogen, the conversion is 50%.

There are two methods of calculating the conversion, i. Measurement of the inflowing and outflowing gases and analysis of the outflowing gases and 2. Analysis of the outflowing gases and measurement of the water produced on the basis of known ones stoichiometric relationships. In general, the latter method has been considered the more reliable results and most conversions calculated according to it.

The delay of the catalyst was partly in solid, partly in liquid State carried out. The results showed none after either procedure significant differences. The addition of the retarder can be either intermittent or take place continuously and thereby the loss of the retarder in the system to be caught up again. In the case of solid catalysts, however, arise in their layer different degrees of delay, so that in practice it is easier and simpler to to work with a liquefied layer, as the continuous mixing of the Catalyst causes a homogeneous distribution of the retarder.

There are several methods of retarding a solid catalyst layer. For example, according to one method, the catalyst is first activated in a known manner by hydrogenation with hydrogen or by reaction with carbon monoxide or a mixture of hydrogen and carbon monoxide. When carbon monoxide is used either alone or in admixture with hydrogen, the process is known in the industry as forming. After the catalyst has been activated, a suitable carrier gas, such as hydrogen, carbon monoxide, or a mixture of both in the form of synthesis gases, to which an organic halogen compound is added in an amount that corresponds to its saturated vapor pressure, is passed over the catalyst at a temperature that is equal to Decomposition of the halogen compound is sufficient. If the retarder used consists of a gas such as chlorine, it can be admixed with the feed gases in a bypass flow. The temperature of the catalyst layer during the delay may vary depending on the halogen compound used. Temperatures of 75 to 100 ° are sufficient if the halide consists of a readily decomposable iodine compound. Temperatures from Zoo to 300 ° or higher are required for the more stable bromides and chlorides. The amount of halide used to treat the catalyst can be varied depending on the degree of retardation desired. Depending on the conditions, the amount can vary between 1 and 300 g per kilogram of catalyst. Iron or iron-silica catalysts can be delayed and thus an increase in the olefin content and a reduction in the formation of carbon dioxide during the synthesis can be achieved if the catalyst is used for 2.5 hours at a flow rate of 400 and a temperature of 240 to 300 ° is treated with an equimolar mixture of hydrogen and carbon monoxide which has been saturated with ethylene dichloride at room temperature and 17.5 at pressure.

In practice, the retarder can be the synthesis gas be added after the catalyst has been activated while the operation is in progress. In order to avoid that the catalyst is completely deactivated, it is advisable to to start with a small amount of the retarder in the syngas and gradually increase the concentration, causing a change in the composition of the reaction products has the consequence. The percentage of carbon dioxide in the outflowing gases can can be measured with an automatic recorder. A significant drop in the carbon dioxide content of the gases produced indicates that the delay took place Has.

After the catalyst has been sufficiently retarded, the Effect gradually wears off after a while. At the same time one can observe that the Catalyst loses halogen. From then on it is used to maintain a constant delay required that this loss be made up, preferably by continuous Adding the retarder to the synthesis gas. The lasting effect of the delay After removing the retarder from the feed stream, it will undoubtedly be temporary Trapping of the halide in the catalyst caused. Such retention of the Halide is illustrated in the specific example above where after 4 days Operation after the introduction of the retarder of the chlorine content of the catalyst Analysis according to the following values: at the beginning and entrance of the catalyst layer 6.0%, in the middle 3.3% and at the exit 2.3% (Cl in percent by weight).

Another method of incorporating the retarder into a solid The catalyst layer consists of a carrier gas saturated with the retarder at room temperature over a catalyst with a temperature slightly above that of the carrier gas is passed until a sufficient amount of the retarder is removed from the catalyst is adsorbed. This heats the catalyst with the adsorbed retarder, generally above 200 °, so that the organic halogen compound decomposes.

As noted above, the retardation effect slowly disappears due to the progressive loss of halogen from the retarded catalyst during synthesis. For the most part, the loss of the halogen appears in the form of hydrogen halide in the waste water from the reaction vessel. Thus, it is more advantageous to add the retarder to the synthesis gas in small amounts after initially adding from 1 to 300 g of halogen per kilogram of catalyst, so that the formation of olefins remains high and the formation of carbon dioxide remains low. For example, an iron catalyst in a liquefied state required 5 to 15 grams of chlorine per kilogram for initial retardation, the chlorine being introduced as ethylene dichloride with the synthesis gas. The catalyst was then kept in the delayed state by adding ethylene dichloride to the synthesis gas at a rate of 0.5 g of chlorine per kilogram per hour (corresponding to 0.7 g of C, H @ C12 per kilogram of catalyst per hour).

It is believed that the loss of chlorine from the delayed catalyst is related to an equilibrium between the iron halides and hydrogen. In the case of ferric chloride, the equilibrium can be represented as follows: Fe-Cl, + H2 T Fe + 2 HCl Thus the chlorine content of the catalyst is gradually exhausted, since hydrogen chloride goes out of the reaction zone with the gases formed, unless chlorine in a suitable form with the gases is fed. The amount of chlorine required to keep the catalyst in the retarded state at different temperatures can be calculated from the following equation: K = equilibrium constant = (PHCl) z (in abs. PH2 Atm.). T (° K) = absolute temperature pHcl = partial pressure of H Cl in absolute. Atm. pH2 = partial pressure of H2 in absolute Atm.

For other halogens, equilibrium and equilibrium constants are given by the following relationships: Fe Br2 + H2 Fe. + 2 H Br Fe J2 + H2 =: z # :: Fe + 2HJ For example, using these relationships, at temperatures from 25o to 50o and a pressure of 18 atm., Absolute (i7.5 at), a partial pressure of the exiting hydrogen of 6 atm. and an outflow rate of the gases of 500 liters per hour in the case of a reaction under normal conditions, the amounts of bound or free chlorine in the added retarder in order to maintain the retardation approximately the following; the lowest values correspond to the lowest temperatures, and vice versa. Halogen amount (grams per hour) Chlorine ................. ..... 0.04 to q. Bromine ..................... 0.015 to 2.5 Iodine ....................... 0, o7 to 8 From this it can be seen that the concentration of the retarder in the synthesis gas is important and the amount which must be added to maintain the retardation increases with temperature and depends on the conditions which affect the equilibrium.

The curves in the drawing show the effect of changing the rate of addition of the retarder during certain periods of time. The rate of addition is shown graphically as the abscissa in the form of a ratio: the pressure of the hydrogen chloride (calculated on the assumption that all added ethylene dichloride retarder is decomposed to gaseous hydrogen chloride) divided by the calculated pressure of the HCl, which is in equilibrium with FeC12 and H2 according to the equation above. The term pHcl means the partial pressure of the hydrogen chloride in the moist gases emerging from the reaction vessel, calculated on the assumption that all of the retarder added (ethylene dichloride) decomposes and forms hydrogen chloride and that none of this is lost in the reaction vessel. The term p ° HCl means the equilibrium partial pressure of hydrogen chloride, calculated from the above equation. The ratio of PHc1 to P ° HCl then indicates the theoretical excess or deficit of the retarder. The data shown in the graphs were obtained in an experiment with a liquefied iron catalyst made from magnetite. The synthesis gas (2.2 H2: z CO) was used at a pressure of 4.2 atm and fresh gas was fed into the circuit in the ratio z: z. It will be understood that the effects of modifying the procedure and the preparation of the catalyst will differ somewhat from the graphic drawing.

The graphs show that the ethylene content of the C2 fraction increases according to the delay increased while the propylene content of the C3 fraction is very high even with slightly delayed catalysts. The formation of methane decreases with delay, which is very important. By increasing the retarder the formation of carbon dioxide can be completely suppressed or significantly reduced will. It is probably important to have the curve for the implementation as well the methane and carbon dioxide curves drop very steeply in the space where pfcl / p ° Hcl about z is. This shows the sharp change in the results that start with non-delayed catalysts and with fully delayed catalysts will. Working longer at a ratio of pHcl / P ° Hcl greater than = can cause excessive chlorination of the catalyst. If this happens, the catalyst can be regenerated, either continuously or in layers by various methods, such as B. by treatment with hydrogen at high Temperatures or by temporarily reducing the amount of retarder in the feed stream.

A significant number of organic halogen compounds have been used as retarders checked and found usable. According to the invention, any organic halogen compound be used, which changes to a vaporous state at the reaction temperature. Halogen compounds that have been evaluated by us are the following: n-butyl chloride, tert. Butyl chloride, ethylene dichloride, z, q.-dichlorobutane, i, 2, 3-trichloropropane, Dichloroethyl ether, glycerol dichlorohydrin, m-dichlorobenzene, p-dichlorobenzene, Carbon tetrachloride, ethylene dibromide, trimethylene chlorobromide, ethyl iodide and n-butyl iodide.

Since the experiments show that the organic retarders halogen or The delay can also set free hydrogen halide in the reaction vessel by treating the catalysts with the halogens themselves, e.g. B. chlorine, bromine and Iodine, halogen halides or inorganic compounds containing hydrogen halide able to deliver, such as B. phosgene can be achieved. So there is a whole Set of ways by which the iron catalyst is exposed to halogens or may be exposed to hydrogen halides in the course of the synthesis.

Any known iron catalyst can be used for our process of hydrocarbon synthesis. Iron catalysts containing accelerators can be retarded, and the following accelerators,. which are typical additives for iron catalysts, were present in considerable amounts in the delayed iron catalysts: Si 02, Ti O., Cu, Al, O., Cd, Ni and K, C 03. Either iron or use an iron oxide, although after the reduction or the formation of the catalyst, such as. B. by reduction with hydrogen, carbon monoxide or a mixture of both, the iron oxide catalysts can occur in reduced or carbide state. Liquid catalysts must of course be produced with a suitable particle size distribution so that they have the typical properties of a liquid catalyst layer.

The definition of the individual conditions (variables) for the hydrocarbon synthesis can be done with the delayed catalysts. The delay has an effect within a wide range of these variables. The most important variables are temperature, pressure, flow rate and the ratio of the generated gas that is fed back through the converter to the freshly supplied synthesis gas. In general, any temperature, pressure, flow rate, hydrogen, carbon ratio, and recycle ratio generally suitable for hydrocarbon synthesis can be used. The following information may serve as an explanation: Temperature ................. 25o to q.20 ° Pressure ...................... 4.2 to 42 at Flow velocity .... zoo up to 5000 (V01./ Vol. Catal.% Hrs.) H =: CO ratio ........... i: 2 to 5: Z Return ratio ...... o to io: i The reaction temperature is undoubtedly the most important variable in this process. Although the percentage of conversion increases with temperature for both delayed and untreated catalysts, conversion with a delayed catalyst at the same reaction temperature is lower than with an untreated catalyst if the other conditions are met are the same. It can be seen from this that the temperature sensitivity, ie the dependence of the effectiveness on the temperature, as well as the effectiveness of the catalyst is reduced by the delay and thus the delay of the catalyst simplifies the monitoring of the temperature in the strongly exothermic synthesis. Working with the delayed catalysts at 320 to q.00 ° is possible. As we found, higher temperatures are not disadvantageous, as they result in highly olefinic products without increasing the formation of methane. With non-delayed catalysts, a considerable formation of methane occurs at higher temperatures. Working over a wide temperature range has also shown that wax formation and deposition of carbon on the catalyst as a result of the retardation are significantly reduced. The reduction in wax formation and carbon deposition achieved in this process is of considerable importance because it increases the life of the catalyst before it has to be regenerated.

In the following examples, experiments i to 6 relate to solid catalyst layers and experiments 7 to 9 on liquid catalysts. Solid catalysts Apparatus and procedure: The reaction vessel consisted of a 0.635 cm wide (inner diameter) steel pipe which contained the catalyst and from an isolated and with a eutectic mixture of phenyl ether and 26.5% diphenyl-filled steel jacket was encased. The steel jacket was with resistance wire wrapped for electrical heating. The catalyst tube was turned on in the jacket both ends fastened with compression sleeves, which allow the attachment and removal of the catalyst tube Make it easy. The amount of catalyst was 20 cc; she was before loading measured in a measuring cylinder and spread over a length of about 63.5 cm of the tube. The catalyst was held in place by packings of copper gauze at both ends held.

The catalyst was placed in a steel tube of appropriate length. This was fastened in the empty jacket with the help of the pressure sleeves. Both ends of the tube were soldered into the copper tubing that connected the rest of the apparatus. The system was tested for leaks with carbon dioxide or nitrogen at a pressure of 17.5 to 20 atmospheres. The gases used for hydrogenation or synthesis (hydrogen, carbon monoxide or their mixture) were then introduced into the apparatus and the temperature of the reaction vessel was brought to the level suitable for the gases (usually 300 to 35o °). The formation generally took place at atmospheric pressure and a flow rate of 100 to 3,000 (2o to 6o liters per hour). After the formation, the temperature of the reaction vessel was usually lowered to a level suitable for synthesis. This could be brought about by the synthesis gases flowing in further. As soon as the suitable reaction temperature was reached, the synthesis gases were introduced at the required pressure, usually 17.5 atm. Example I Ethylene dichloride retarder The catalyst, FeO: CuO: SiO2 (100: 2.5: 100 parts by weight), was prepared by precipitation from a solution of copper and iron nitrates with sodium carbonate to -px 7.8. Then silica in the form of kieselguhr was added and the mixture was boiled. This mixture was then filtered and the precipitate washed. The bulk density of the finished catalyst preparation was about 0.9 g per cubic centimeter. The catalyst was then placed in the reaction vessel and treated with carbon monoxide for 2 hours at 31 ° to 335 ° and a flow rate of 3,000. The synthesis gases in a ratio of 1 mol of hydrogen to 1 mol of carbon monoxide were passed over the catalyst at a pressure of 17.5 at and a flow rate of 300 and the product obtained was continuously analyzed. After a certain time, the synthesis gas was passed through ethylene dichloride at the reaction pressure and a temperature of 25 ° and saturated with it, so that the retarder was fed to the catalyst over a total of 31 / Z hours, a flow rate of 30o to 400 and a catalyst temperature of 28o ° . The amount of retarder was about 40 ccm in vapor form. The amount of ethylene dichloride added corresponded to about 25 g of chlorine per kilogram of catalyst. A comparison of the reaction conditions and results with delayed and non-delayed catalysts is given below: - Before the After the Average delay delay Lifetime of the catalytic converter in hours ........ 31 194 197 Temperature in ° C .............................. 270 290 297 Implementation in II / 6 ............................... 8o 68 56 Composition of the resulting hydrocarbon substances in ° / o (as defined above) CH4 .. :: .................. .................. 18 14 15 15 C2,4 .................... 3 9 12 C3 H6 C2 to C4 OIefine. . *** '«' *** '' .......... 13 25 20 22 44 C4H8 .................... 9 12 13 C2H6 - .................... x = 21 13 C3 14. C2 to C4 paraffms ..... ................ 3 16 - - 2I C2Hla .................... 2 2 6 C5 -f- ........................................... 41 22 I9 20th D02 / C02 - [- H20 (molar ratio) ................. 0.75 0.32 0.24 o, 28 It can thus be seen that the delay causes an increase in olefin formation and a marked change in the molar ratio of carbon dioxide to water formed during the reaction, the amount of carbon dioxide decreasing and the amount of water increasing. The delayed catalyst was therefore less active, as can be seen from the low conversion at a higher temperature. Example 2 Ethylene Dichloride Retarder The catalyst consisted of taconite iron ore; the synthesis was carried out as in Example I. The catalyst was reduced with hydrogen at 450 ° for 20 hours. The delay was brought about by passing over the catalyst heated to 325 ° for 3 minutes 2.81 hydrogen which was saturated with ethylene dichloride at room temperature and atmospheric pressure. The amount of retarder fed in corresponded to 0.9 g of chlorine and about 30 g of chlorine per kilogram of catalyst (the catalyst used had a volume of 20 ccm and a bulk density of 1.6 g per cubic centimeter). The reaction conditions and results before and after the delay are shown in the table below Conditions Before the delay I After the delay Ratio HZ: CO ................................. I: II: I Pressure in at ...................................... I7.5 1715 Lifetime of the catalytic converter days ................. 2 9 Temperature in ° C ................................. 288 336 Flow rate ........................... _ 420 42O Conditions I Before the delay, After the delay Results Total implementation in ° / o ........................... 40 37 C02 / C02 -E- H20 (molar ratio) .................... 0.31 o, o6 Hydrocarbons formed in ° / a (as defined above) C H4 ............................................. 22.5 20.7 C2H4. . . . . . . . . . . . . . . . . . . . . . . 2.1 12.5 C3H6 C2 to C4 olefins. ........................ 12 23.1 18.5 42.5 C4H8 ....................... 9 11.5 C2 H8. . . . . . . . . . . . . . . . . . . . . . . 7.9 3.7 C3H8 C2 to Cr paraffins ........................ 3.8 16.7 1.5 6.9 C4 Hlo ........................ 5 1.7 C5. ............................................ 38 30 This example shows that with the same high yield of C2 to C4 fractions with a non-delayed catalyst, the effect of the delay is a remarkable increase in olefins, a sharp decrease in carbon dioxide and a decrease in methane formation despite the higher temperature of the delayed catalyst . Example 3 Different amounts of ethylene dibromide as a retarder. The catalyst was the same as in Example 1.

The introduction of the retarder was carried out in the same way, only the temperature of the catalyst during the retardation was 24o to 26o °. The composition of the synthesis gas was 1 H2: 1 CO. The other conditions and results are listed below: Amount of C2 H4 Br2 produced hydrocarbons in Steam Kgakgatal Temp. C synthesis reaction estimation C02 C02 ccm CH4 olefins paraffins G + . - / - H20 80 32 293 47 - 0.39 1 1 38 23 38 250 100 295 39 o, 1o 15 38 16 1 Example 4 Ethyl iodide retarder The catalyst consisted of equal parts by weight of Fe 2 O 3 and S'O 2 and had a bulk density of about 0.9. The carrier gas contained volatilized ethyl iodide as a retarder in an amount of 150 cc of steam under standard conditions (about 95o g of iodine per kilogram of catalyst). It was passed over the reduced catalyst at 75 to 86 °, a large amount of retarder being required as a result of the low treatment temperature. The composition of the synthesis gas was 1 H2: 1 CO. The other conditions and results are given below. Reaction temperature in ° C ............ 299 conversion into "/ a .................... . 35 C02 / C02 + H20 (molar ratio) ....... o, 2o formed hydrocarbons in ° / o (as defined above) CH4 .................. ............... 20 C2 to C4 olefins ..................... 41 C2 to C4 paraffins .. ................. 1o C5. .............................. .. 29 Example 5 Various organic chloride retarders Various organic chlorine compounds were passed over a reduced Fe203-S'02 (equal parts by weight) catalyst mixed with the carrier gas according to the procedure of Example 1. The synthesis gas consisted of 1 H2: 1 CO further reaction conditions and results are given below: Men des delay i, 4-dichloro-i, 3-dichloro-i, 2, 3-trichloro ge gerers butane benzene propane ccm steam ................................. 200 1500 300 g / kg catalyst ............................ 36 270 54 Delay temperature in ° C ................ 22o to 26o 22o to 26o 225 to 240 Reaction temperature in ° C ................... 302 269 253 Implementation in ° / o ............................ 54 44 42 C02 / C02 -f- H20 (molar ratio) ............... 0.36 0.15 o, 12 Amount of 'retarder', 4-dicloro-r, 3-dichloro-x, 2, 3-dichloro-` butane benzene propane Hydrocarbons formed in ° / o CH, ........................................ 20 14 z5 C2 to C4 olefins ............................. 35 36 30 C2 to C4 paraffins. . ......................... 22 13 20 C5. ....................................... 23 39 35 The typical effect of the retarder on the olefin content can be determined in each test.

Example 6 Hydrogen chloride as a retarder A catalyst made from iron, Silicic acid and copper, (xoo parts by weight Fe203 -f- zoo SiO2 -f- 2.5 Cu) was by passing over a mixture of hydrogen chloride and synthesis gas (z H ,: z CO) delayed at about 70 °. The amount of hydrogen chloride added in this way was about 1.5 g. The results are recorded below:.

Lifetime of the catalyst in hours 168 Reaction temperature in ° C ............ 271 Conversion in ° / a ...................... 49 C02 / CQ2 + H20 (molar ratio) ....... 0.30 - Hydrocarbons formed in ° / a CH ....................... ........... 15 C2 to C4 olefins ..................... 30 C2 to C4 paraffins ........ ............ 13 C ;, -E- ............................... . 33 the striking increase in the olefin is remarkable.

Liquid catalyst layer Apparatus and procedure: The reaction vessel consisted of a steel tube with an inner diameter of 7.6 cm, which was connected to a Jacket, which was filled with a circulating fluid. The coat was heated electrically. The catalyst was filled in the reaction vessel and obtained by passing the synthesis gases through the bed in a liquid state. The effluent gases went through a 25.4 cm wide (inside diameter) heater. the ceramic or sintered metal filter contained so that the suspended catalyst could be recovered. The recovered catalyst was increasing from time to time Time blown back into the catalyst layer. The escaping gas flowed under reaction pressure through a water-cooled condenser to remove liquid components to remove. The gases flowing into the reaction vessel were calibrated with the aid of calibrated Openings measured and the escaping gas flowed through dry gas meters. For the purpose of possible recirculation of part of the gas produced were special devices intended.

Example 7 Ethylene Dichloride - Continuous Retardation of Iron Oxide (Fe203) in pigment fineness was mixed with water to form a thick paste. the Paste was dried in an oven and then sintered at 130 ° for 2 hours. Of the Catalyst was crushed and ground to a fineness that all particles passed through a 27o mesh screen (0.055 mm hole size). The finest catalyst particles less than 2o, u in size were removed by electrical cleaning. The catalyst @v was reduced with hydrogen and filled into the reaction vessel; its volume was 4920 cm3.

As stated above, the delay effect stopped. of The catalyst gradually rises as a result of the loss of halogen, if it is only one Treatment with the retarder was subjected. If z. B. the above catalyst initially treated with about 17 g of chlorine from the ethylene dichloride, it gave one C2 to C4 fraction, which contained 67% olefins, with a conversion of 48% and a recycle ratio-of x: z. After a while, the in continuous operation with the same catalyst produced hydrocarbons 36% olefins in the C2 to C4 fraction, and the conversion increased to 63) / " which means a considerable loss of the delay effect. The loss of chlorine from the catalyst layer could also be determined by the fact that the resulting Water of reaction contained hydrochloric acid.

After adding the ethylene dichloride to the synthesis gas at a rate of 7 g per hour (rg chlorine per _ kilogram of catalyst) decreased. the conversion in the course of 14 hours to 43%, and the olefin content of the C. to C4 fraction rose to 72%. The ethylene dichloride was then added continuously in an average amount of 0.3 g of Cl per kilogram of catalyst per hour over a further 25 hours; the feed rate was kept high enough to prevent any increase in the activity of the catalyst as measured by the percentage conversion.

The conditions and results before and after the previous continuous delay are shown in the table below: Before the continuous After the continuous delay delay Pressure in at ...................................... 17.5 17.5 Linear speed in cm / sec ................. 12.2 to I5.2 12.2 to 15.2 Synthesis gas to supplement, H2: CO ............... 2.2: I 2.2: I Return ratio ............................ 1: I 1: 1 Lifetime of the catalyst in hours ........... 579 618 Temperature in ° C ................................. 312 318 Total implementation in% ........................... 63 46 Hydrocarbons produced in% CH4 ............................................. 26 14 C2H4 ....................... I 9 C3 H6 C2 to C4 olefins. ........................ 13 21 20 42 C4 H8 ....................... 7 13 C2H6 ....................... x9 7 C3 H8 C2 to C4 paraffins ........................ xo 36 4 17 C4Hlo ........................ 7 6 C5. ............................................ 17 27 Olefins in the C2 to C4 fraction in% ............. 36 72 Propylene in the C2 to C4 fraction in% ............ 23 34 C02 / C02 + H20 (MO ratio) ..................... o, 28 0.034 The continuous addition of the retarder thus causes a significant increase in olefins and a sharp decrease in the formation of carbon dioxide over a longer period of time.

Example 8 Ethylene Dichloride - Continuous Delay The experiment of Example 7 was continued with a recycle ratio of the resulting gas to synthesis gas of 3 to 1 and at various temperatures. During a test duration of 69 hours, ethylene dichloride was added continuously at an average rate of 0.8 g of Cl per kilogram of catalyst per hour. The conditions, results and analysis data are shown in the following table: Before the continuous After the continuous delay delay Pressure in at ....................................... I7.5 17.5 Linear speed in cm / sec .................. 12.2 to 15.2 12.2 to 15.2 Synthesis gas, H2: CO ............................... 2.2: I 2.2: I Repatriation ratio ............................ 3. 1 3. I. Lifetime of the catalyst in hours ........... 7o8 751 Temperature in ° C ................................. 319 330 Total implementation in% ........................... 71 80.5 Hydrocarbons produced in "/ o CH4 ............................................. = 7 18, O C2H4. . . . . . . . . . . . . . . . . . . . . . . 3.6 2.4 C3H6 C2 to C4 olefins. ......................... 17.5 31.1 16.9 29.5 C4H8 ....................... 10.0 10.2 C2H6 ....................... 12.5 12.2 C, H8 C2 to C4 paraffins ........................ 4.5 20.2 5.0 20.5 C4Hlo ....................... 3.2 3.3 C5 -f- ............................................ 32 32 Olefins in the C2 to C4 fraction in o / o .............. 6o 59 Propylene in the C2 to C4 fraction in% ............ 34 34 C02 / C02 + H20 (molar ratio) .................... 0.047 0.046 Working at high recycle and elevated temperature results in a greater overall conversion. The retarder undoubtedly also increases the olefin content of the C2 to C4 fraction, in spite of the fact that with higher recycling the conditions for the hydrogenation of the olefins to paraffins are much more favorable due to the longer residence of the olefin molecules in the reaction vessel. Example g. Chlorine gas as a retarder Work was carried out for a long time with an iron oxide catalyst with the continuous addition of ethylene dichloride. Then with the introduction of the retarder into the gas fed in, the synthesis would be continued for hours. During this time chlorine escaped from the catalyst layer in the form of hydrogen chloride, and the formation of carbon dioxide and the percentage conversion increased. Chlorine gas was then fed in small, measured amounts to the synthesis gas To for hours in order to retard the catalyst again. The conditions and results during the deceleration with ethylene chloride, g hours after the cessation of the deceleration current and after the deceleration with chlorine gas are shown below: Conditions temperature in ° C .......... 338 to 340 pressure in & t .. ............. 4.2 recirculation ratio ..... i: i flow rate ... 400 synthesis gas ............... (2 - 2 H2 + x CO) Amount of catalyst .......... 12 kg Results delay 'Carbon distribution in / o with respect to set during deceleration After deceleration delay with C2 H4 Clz with chlorine gas g CH4 ............: ................, .. 17 30 17 C2 to C4 (in total) .................. 64 58 65 C5. ....: .......................... 1g 12 18 ° / o Olefuie in the C2 to C4 fraction .... 79 6o 77 C02 / H20 --- C02 (molar ratio) ...... . 0.05 o, 16 0.04 This proves that the retardation with chlorine gas corresponds to the original retardation with ethylene dichloride. When the delay is interrupted at the high temperature. the increase in methane formation as well as its control when delayed again is noteworthy. .

Claims (3)

PATENTA-NSPRJJC.HE: -i. Process for the production of hydrocarbon mixtures, which have a relatively high content of normally gaseous olefins 2 to q .. carbon atoms, characterized by the fact that carbon monoxide and hydrogen are reacted in the presence of an iron catalyst, the The catalyst is brought into contact with substances during the synthesis Contain chlorine, bromine or iodine. 2. The method according to claim i, characterized in that that the chlorine, bromine or iodine-containing substances in small, measured amounts either continuously or intermittently into the gas mixture passing over the catalyst flows, are introduced. 3. The method according to claim i and 2, characterized in that the chlorine-containing substances of elemental chlorine or hydrochloric acid or a compound which elemental chlorine or hydrochloric acid: on contact. with the catalyst to deliver is able to exist. q .. The method according to claim i to 3, characterized in that the chlorine or the hydrochloric acid is present in contact with the catalyst in such an amount that the hydrogen chloride in the gas leaving the catalyst is quantitatively at least the equilibrium ratios of the following equation corresponds to FeC12 - [- H2 <Fe + 2 HCl. 5. The method according to claim i and 2, characterized in that the bromine-containing substances consist of elemental bromine or hydrobromic acid or a compound which is able to give off elemental bromine or hydrogen bromide in contact with the catalyst. 6. The method according to claim 5, characterized in that the bromine or the hydrogen bromide is present in contact with the catalyst in such an amount that the amount of hydrogen bromide in the gas leaving the catalyst corresponds at least to the following equation FeBr2 - i- H2 Fe + 2 HBr. 7. The method according to claim i and 2, characterized in that the iodine-containing substances consist of elemental iodine or hydrogen iodide or a compound which is able to give off elemental iodine or hydrogen iodide in contact with the catalyst. B. The method according to claim 7, characterized in that the iodine or the hydrogen iodide is present in contact with the catalyst in such an amount that the amount of hydrogen iodide in the gas leaving the catalyst corresponds at least to the equilibrium ratios of the following equation Fe I2 + H2 .y Fe --f- 2 HJ. G. Process according to Claims 1 to 3, characterized in that the chlorine-containing compounds are organic chlorides, in particular ethylene dichloride. ok Process according to Claim 5, characterized in that the bromine-containing compounds are organic bromides, in particular ethylene dibromide. ii. Process according to Claim 7, characterized in that the iodine-containing compounds are organic iodides, in particular ethyl iodide. 12. The method according to claim i to ix, characterized in that a mixture of carbon monoxide and hydrogen at above atmospheric pressure, for. B. at about 4.2 to 42 at, is passed over the catalyst. 13. The method according to claim i to 12, characterized in that the mixture of carbon monoxide and hydrogen is passed over the catalyst at a temperature of zoo to 45o °.