DE1209237B - Process for the continuous generation of standard-compliant town or long-distance gas - Google Patents

Description

GERMAN

PATENT OFFICE

LEGAL LETTERING

German class: 26 a-12

Number: 1209 237

File number: M 54737IV d / 26 a

Filing date: November 7, 1962

Opened on: January 20, 1966

It is known to split hydrocarbons with the addition of steam in a reactor with externally heated tubes and to use the fission gases for the production of long-distance gas or town gas. The gases emerging from the tube furnace do not yet have the city or district ^{gas calorific value of 4200 to 4700 kcal / Nm 3} (based on the dry gas), but their calorific value depends on the processing pressure used and the other conditions of the fission, namely reaction temperature and Addition of water clusters, at 1500 to 3300 kcal / Nm ³ . In the newer town or long-distance gas systems, apart from the properties required for a long time by the gas companies with regard to density, the maximum content of non-flammable gases, i.e. the so-called "inert", and the degree of dryness, it is now also required that the content of carbon monoxide 5 or does not exceed 7 percent by volume.

This requirement is made by the societies with regard to the toxicity of carbon monoxide.

This requirement and the need to maintain a certain density in town and long-distance gas, require a multi-stage further processing of the gas produced in the tube gap furnace.

In general, the carbon oxide content of the fission gases, which have been generated by the conversion of hydrocarbons in the tube furnace, has hitherto been reduced to the required maximum permissible value in a downstream conversion system. In this conversion reaction, as much carbon dioxide is produced as carbon oxide is consumed. This increases the density of the city or long-distance gas considerably. It is therefore necessary to wash out carbon dioxide in a downstream carbon dioxide washing plant so that the density of town or district gas required by the gas companies is maintained; after the carbon dioxide washing, cold carburization is carried out in order to obtain the required town or district gas calorific value. For this cold carburization, propane or butane or a mixture of the two or high calorific waste gases from other industrial plants, e.g. B. Refineries added. If necessary, a small amount of air can also be added to the town or long-distance gas to set a certain oxygen content in order to achieve better combustion properties of the gas.

It has now been shown that in cold carburization, especially when heavy gaseous hydrocarbons, how butane and propane are used, if all city or city requirements are met Remote gas, d. H. Calorific value, density, carbon oxide content

Process for continuous production
of standard-compliant town or long-distance gas

Applicant:

Metallgesellschaft Aktiengesellschaft,

Frankfurt / M., Reuterweg 14

Named as inventor:

Dipl.-Ing. Heinz Hiller, Bad Vilbel-Heilsberg;

Dr.-Ing. Horst Bechthold,

Frankfurt / M.-Fechenheim;

Dr.-Ing. Gerhard Baron, Frankfurt / M.

and maximum content of non-flammable gases, ie of "inerts", the hydrogen content of the finished town or long-distance gas rises above 60% and in many cases even reaches 65 to 68%. However, the permissible hydrogen content is generally limited by the gas companies to 60%, because with a higher hydrogen content when the gas is burned by the consumer, the flames tend to flash back into the burner. Attempts have therefore been made to reduce the hydrogen content of town or long-distance gas by various measures, and in many cases have had to resort to other feed gases with a low hydrocarbon content. Naturally, this made it necessary to switch the process to other starting materials.
Another way of keeping the hydrogen content low is to add a small amount of air to the tube furnace in addition to the starting material to be converted. With this method, the carbon dioxide in town or long-distance gas can be replaced by nitrogen. As a result of the lower molecular weight of nitrogen compared to that of carbon dioxide, a larger amount of "inert" can be added to the gas, so that the hydrogen content is somewhat lower with the same density and the same calorific value. However, the added air reacts exothermically with some of the hydrocarbons used in the tubes of the tubular furnace and thereby causes a large increase in temperature and further additional stress on the material, which is already highly stressed. In order to prevent the pipe material from wearing out too quickly, only a limited amount of air can be added to the tube furnace.

509 779/163

3 4

that for the desired lowering of the hydrogen pressure is about the same as the bsi for generating the

it is mostly not enough. Applied when working under fission gases from the starting substances.

Pressure must also be the added air to the In this reaction, the hydrogen content of the

Operating pressure can be compressed by the gas depending on the chosen reaction conditions

additional energy required for this to 5 within wide limits, for example by about 15 to

leads to an increase in the cost of the process. 20 percent by volume. This is

It has now been found that it is possible in any case, regardless of the starting materials to be used, to generate thermal cleavage reactions from, for example, hydrocarbons, city or long-distance gas. or long-distance gas to convert the hydrogen content to the demands of the io, which corresponds to the gas companies of the gas companies. The invention relates to established requirements also with regard to water, a method for the continuous production of substance content. Furthermore, according to the invention, town or long-distance gas at normal pressure or at the same time as the lowering of the hydrogen-increased pressure by endothermic cleavage of the content also increases the carbon oxide content to the value prescribed by the liquid or gaseous hydrocarbons or gas companies, for example refinery exhaust gases or mixtures thereof in a manner 5 Volume percentage, reduced. This is done in an externally heated reactor with the addition of water by choosing a suitable combination of steam and optionally air. The temperature, added hydrocarbon or process according to the invention is characterized in that the split refinery waste gas and added steam, gaseous liquid or gaseous hydrocarbons or zo. are added and the mutual agreement that with constant or mixed at 500 to 700 ⁰ C a catalytic hydrating decreasing hydrogen content is subjected to the volume ratio of generating cleavage, whereupon the hydrogen to carbon oxide remains the same or greater product gas air and / or hydrocarbon 25 will. With the method according to the invention it is possible to add containing gases and / or carbon dioxide, not only those which are withdrawn by the gas companies by leaching. made requirements regarding the heating

The process can be carried out at normal pressure or at value, but also with respect to the hydrogen and

elevated pressure, up to 30 atmospheres, preferably with a carbon oxide content solely by choosing the appropriate ones

Pressure of 10 to 25 atmospheres. Than 30 reaction conditions must be met. An additional

A catalyst for the hydrogenative cleavage can therefore no longer be converted. It can

nickel-containing catalyst or a cobalt-molybdenum prove to be useful when the

Catalyst can be used. System or possibly caused by operating errors

The minor fluctuations in the calorific value that are suitable for generating a cracked gas common substances, for example gaseous or fms-35 of the released gas by adding smaller doses sige hydrocarbons, such as propane, butane, light quantities of hydrocarbons or refinery or Heavy gasoline, refinery fumes or mixtures fumes or similar.

of this, are in an indirectly heated reactor, the drawing shows the flow diagram of a plant,

for example in an externally heated tube which helps to carry out the method of the invention

oven, at normal pressure or under increased pressure 40, for example, is suitable.

from 0 to 30 atmospheres, preferably at a pressure of The system consists of the tube furnace 1, which is 10 to 25 atmospheres, split over a catalyst. For reactor 2, the heat exchangers 3 and 4 and this endothermic cleavage, for example, a carbon dioxide washing system 5 is suitable. The supported catalyst to be processed is a nickel-containing catalyst. In some starting materials, gaseous or liquid coal cases, adding a small amount of air to the starting hydrogens, refinery waste gases, mixtures thereof or similar substances can be advantageous. The cracked gas contains, apart from being supplied to the tube furnace 1 through the line 6 under the pressure of hydrogen, carbon oxide and methane, which is still used, carbon dioxide and large amounts of water vapor. Its through the line 7 is steam, through the line 8 quantitative composition is mainly optionally mixed with air. The reaction conditions used, for example a nickel catalyst, depend mainly on pressure and temperature. That split the mixture at preferably 10 to 25 atmospheres. Fission gas is after it has a part of its sensible The fission gas generated is a part of its sensible heat expediently in a heat exchange heat in the heat exchanger 3, for example exchanger, for example to generate steam or to generate steam or to preheat to preheat Feedstocks or the like, released 55 feedstocks or the like, and then passes into the has, passed into a reactor and in the presence of a reactor 2 which is equipped with a catalyst, for example a catalyst, for example a nickel-containing catalyst, or with a nickel-containing catalyst a lysators, a nickel-containing supported catalyst or cobalt-molybdenum catalyst, the z. B. with sulfur-free cobalt-molybdenum catalyst with the addition of containing starting substances can have advantages, hydrocarbons and possibly with the addition of 60 is filled. Through the line 9 gaseous further steam of a hydrogenating cleavage or liquid hydrocarbons, refinery exhaust gases are thrown. Suitable hydrocarbons are, for example, or mixtures thereof and, through line 10, propane, butane, light or heavy gasoline. if necessary, further steam is added. The men-also refinery waste gases and the like, as well as mixtures of the above substances supplied through the lines 9 and 10 are suitable. The reaction 65 products and the temperature in reactor 2 are ^{coordinated at temperatures of 500 to 700 0} C, preferably so that a city or wise at temperatures of 550 to 650 ^: C, by remote gas with the desired calorific value, Hydrogen-led. The carbon oxide content that is used and the resulting carbon dioxide content is appropriate. The waste heat of the

Claims (1)

5 6 generated !! Gas is in the heat exchanger 4 in this way generated town gas possesses at a density for example to generate steam or to a ratio of 0.42 (air = 1), a calorific value of Preheating of the substances to be processed 4650 kcal / Nm ³ and shows the following analysis values: used, in the carbon dioxide washing plant 5 is the "gas is freed of carbon dioxide until the 5 COo is 9.8 mole percent prescribed gas density considering CO 4.5 mol percent a possible air charge has been reached. Depending on the jf _o 545 mole percent the selected carbon dioxide washing procedure is followed by the CH ₁ '!! "" !!! "!!!" υ! 14J mole percent Cold or danipi-saturated gas with higher temperature. into the car wash. For example, when using 10 liquefied gas 4.0 mole percent preparation of a hot potash or monoethanol lamb O ₂ 0.5 mole percent wüsche can feel the sensible and steam heat of the gas N ₂ 1.9 mole percent iüf the regeneration of the washing liquid used will. The hydrogen content of this gas is according to the from Quantities of hydrocarbons or refineries below the values required by many gas companies are too high, gases added for fine control of the calorific value. From the same liquefied gas specified above will. In normal operation, this is town gas in the method according to the invention Usually not necessary. The line 12 can produce that with the same density and the same if necessary, air can be added to the gas in order to have a significantly lower calorific value and therefore to set a certain oxygen content of the gas below the maximum of the gas companies place. The gas leaves the system through the line with a permissible hydrogen content. 13 and after drying it stands as a finished city map. or remote gas available. 10 915 Nm ³ cracked gas of the above composition are released after leaving the tube Examples ² 5 cooled in the oven to 560 "C. The cracked gas 2540 kg of steam from 560 ^: C and 760 kg of liquefied gas the A liquid gas is converted to the previously known composition specified above using a Tempe method. ie by cleavage in a tube furnace, mixed in at a temperature of 300'C and the resulting conversion, carbon dioxide scrubbing mixture at 20 ata over a nickel catalyst and cold carburization, a town gas is produced. The 30 split by hydrogenation. The process is exothermic, using commercially available liquefied petroleum gas. ^{10 823 Nm 3 of} gas emerge from the reactor has the following composition: Mixture of the following composition with one CH, "2.0 mole percent temperature from 620 to 63O = C from: C ₂ H, 4.0 mole percent _3- CO ₂ 18.9 mole percent C ₁ H, 26.0 mole percent CO 3.7 mole percent C ₁ Hj ₀ 60.7 mole percent H ₃ 49.2 mole percent QH _1. , 0.3 mole percent CH ₁ 28.2 mole percent CH .. 2.0 mole percent ^. ^,,. - _{τ Γ Λ} , ".., '40 This gas has the density related to air = 1 ^c i ^H " ⁵ > ° mol percent _{0515 and an upper} calorific value of 4297 kcal / Nm * By cleavage in a tube furnace it becomes and lies with these properties and its water Fission gas with the analysis values: substance content in the range that applies to town gas Norms. CO ₁ , 15.4 mole percent ₄₃ After utilizing the heat of the gas mixture CO 9.4 mole percent is the carbon dioxide content in a hot pot j- { _{i (} 60.3 mol percent washing reduced to 10.1%. After the addition of CH wWolorozent ^Lllft 10 000 Nm ^{3 of} finished town gas with the ^{1 'F} composition generated, the following increase after the conversion 50 qq gg mole percent tns beitt: " Ί we have:, -, -. λΊλλιτ ι CO 4.0 mole percent CO ₂ 19.3 mole percent H ₂ 53.1 mole percent CO 4.3 mole percent CH ₁ 30.6 mole percent Ho 62.2 mole percent 35 O ₂ 0.5 mole percent CH ₁ 14.2 mole percent N ₂ 1.9 mole percent Part of the carbon dioxide is in the carbon and an upper calorific value of 4650 kcal / Nm ³ and Dioxydwaschanlage washed out and the gas with a density ratio of 0.42 (air = 1) received. Composition 60 COo 10.5 mole percent claims: ^{CO 4} " ^{8 mol percent} 1. Process for the continuous production of H ₂ 69.0 mole percent town or district gas at normal pressure or below CH ₁ 15.7 mol percent 65 elevated pressure by endothermic cleavage of liquid or gaseous hydrocarbons in the case of cold carburization, liquefied petroleum gas of the specified or refinery exhaust gases or mixtures thereof Composition and air mixed in. The on in an externally heated reactor with the addition of Steam and optionally air, characterized in that liquid or gaseous hydrocarbons or refinery exhaust gases or mixtures thereof and optionally steam are added to the cracked gas and the mixture is ^{subjected to a catalytic hydrogenation cleavage at 500 to 700 0} C, whereupon the product gas optionally air and or . or gases containing hydrocarbons are added and / or or carbon dioxide can be removed by leaching. 2. The method according to claim 1, characterized in that the method at 10 to 25 atm is carried out. 3. The method according to claims 1 and 2, characterized in that as a catalyst for the For hydrogenative cleavage, a nickel-containing or cobalt-molybdenum catalyst is used. 1 sheet of drawings 509 779/163 1.66 © Bundesdruckerei Berlin