DE1567728A1 - Process for producing a gas rich in hydrogen and carbon from carbon distillation gases - Google Patents

Description

PATENT LAWYERS 1 R R 7 7 9 ft

DR.WPBADT \ 00 / (4.0

DIPI.ING.E.E.PINKENEH Dr, C. Otto * Coap. society Dipl.-Ing. _Bochum * · ERHESTI «it limited liability, B ο chu Heinrich-König-Straße 12 -—-— ■ ——-————— «———————-—-—————— Telephone: 41550, 42327

10/65
EEP / HS

Process · η »wc Generation · ίη · β of hydrogen and carbon are rich in gases from carbon distillation gases

SI «The invention relates to a process only by producing a gas rich in hydrogen and carbon oxide catalytic «splitting of carbon distillation gases into Presence of water vapor and optionally oxygen-containing gases, which are used as exit gas for the generation of a Uasee usable for chemical purposes, see p. B. one Syntheeegaaea or the like can be used.

The dry distillation τon coal see B. in Coke ovens contain a distillation gas Heihe τοη accompanying substances such. B. benzene and naphthalene hydrocarbons, Tar, hydrocyanic acid, ammonia as well as hydrogen sulfide and organic sulfur compounds. It is already known that from such gases the undesired ones Accompanying substances »u removed and the cleaned Gas bit water vapor and possibly air catalytically converted into a gas rich in hydrogen and carbon dioxide. The catalytic cleavage usually takes place on nickel catalysts. The removal of the accompanying substances requires a complex work-up of the crude distillation gases, which also includes the accompanying substances as such incurred that either have to be destroyed or further processed

It also includes a procedure su? Purification of coal distillation gases with the advice of a charcoal o * yd

009826/0306

IOD / / £. O

and hydrogen-rich fuel gas of the state of the art, in which the crude distillation gases are converted at temperatures between 700 and 1300 ⁰ C in the presence of clay gasifying agents using τοη cracking catalysts and then the acidic impurities remaining in the cracking gas, such as hydrogen sulfide, from the cracking gas removed. The endothermic reaction must be carried out in chambers or the like, which are preferably externally heated and which consist of ceramic materials, since metallic materials cannot withstand the stresses occurring in the presence of the hydrogen sulfide contained in the dea to be cleaved. The use of ceramic building materials is disadvantageous in that, because of their low thermal conductivity and the greater thickness required compared to metallic materials, they require high boiler room temperatures and only allow a low heat flow per unit surface area of the chamber. Furthermore, the use of significantly increased operating pressures in chambers made of ceramic material is not possible. Bas known method also requires the use of sulfur-resistant catalysts and longer residence times, which are due to the fact that the activity of such catalysts, eg. B. that of nickel sulfide is less than the activity of non-sulfur-resistant catalysts, e.g. B. of metallic nickel.

The invention is based on the object of carbon distillation gases under assists in cumbersome and lengthy cleaning processes on hydrogen and

009826/0305

To produce carbon-oxide-rich gas, with the disadvantages the known method described should be avoided in which the crude distillation gases directly be subjected to catalytic cleavage.

In the process of generating τοη oases rich in hydrogen and carbon oxide by catalytic cleavage τοη coal distillation gases in the presence τοη water vapor and optionally oxygen-containing gases, in which the raw gases leaving the coke oven are cooled and the liquid hydrocarbons and the condensate water are separated off, The invention consists in that the gases are then compressed to a pressure τοη 1.5 to 30 ata, preferably 3 to 10 ata and ^{catalytically hydrogenated at temperatures between 250 to 700 0} C, Tor * ugsweiee 300 to 500 ⁰ G, whereupon one the hydrogen sulfide is largely removed from the gas by known purification processes and, after the addition of steam and optionally oxygen or air, the gas is continuously converted into a gas rich in hydrogen and carbon oxide in a ^{manner known per se at temperatures between 600 and 1200 ° C.}

In the catalytic hydrogenation of the cooled grass, which is carried out in a known manner on cobalt-molybdenum catalysts is carried out, the organic sulfur compounds are converted into hydrogen sulfide, its removal, for example, with fiaseneisenerz or Zinc oxide to less than 10 ppm. can be done. When the gases are hydrogenated, not only the organic

00 9 8 26/0305 - 4 -

Sulfur compounds converted into sleeping hydrogen and the accompanying substances contained in the gas such as Hydrocyanic acid, ammonia, and nitrogen oxide to a greater or lesser extent in their girdles, but also the olefins almost entirely into saturated hydrocarbons converted · Those still present in the hydrogenated gas after the removal of the hydrogen sulfide Admixtures such as ammonia, traces of hydrocyanic acid and nitrogen oxides and the like interfere with the subsequent process Implementation not · It has surprisingly been found that the conversion of the olefins the effectiveness of the catalyst in reacting the gases with water vapor and optionally oxygen or air can be increased significantly, which makes it possible to carry out the same conversion with either shorter residence times or at lower temperatures than those used in the cracking of non-hydrogenated coal distillation gas is required, the sulfur content by other means, such. B. activated carbon on the same fourth has been brought into the nickel catalyst at the point of entry. The possibility of a specific To be able to obtain the degree of conversion even at lower temperatures is of great advantage because the catalysts are generally arranged in metallic bores and the application of higher operating pressure is possible with the same pipe wall thickness

Since in most cases the gas produced is required under pressure, another advantage of the process is that that this pressure already exists in the preliminary stages

009826/0305 " ⁵ "

iat. According to a further feature of the invention the compression of the cooled gases in several stages carried out, It has proven to be expedient to dissipate the heat of compression after the individual To undertake steps according to the invention in such a way that the dew point for the naphthalene still contained in the gas is not reached or is even below it.

In a further embodiment of the method can one gate of the hydrogenation contained in the cooled gas and the naphthalene hydrocarbons completely or partially remove · inventionsegeeäö can be used to remove the naphthalene hydrocarbons when cooling the fiohgases liquid use hydrocarbons. You naphthalene hydrocarbons can be removed before or after compression or after each compression stage will·

The catalytic conversion can be carried out on known catalysts are made * which do not need to be sulfur-resistant; for example one can use nickel catalysts use a carrier material

The invention is illustrated below using two exemplary embodiments explained}

example 1

£ in distillation gas emerging from the receiver of a coke oven was after deposition of the thick tea on a

009826/0305

- 6 -

Temperature of 20 ⁰ C cooled. After the removal of the liquid hydrocarbons and the condensate water, the gas had the following composition

CO ₂ 1.6 VoI • - j » Heavy hydrocarbons 2.3 VoI · - *> CO 5.2 VoI .- * ^H 2 59.6 VoI .- * CH ₄ 25.7 VoI .- * 5.6 VoI

and contained the following accompanying toff per normal cubic meter

1Θ g tar

29.6 g benzene and homologues

0.4 g naphthalene

9.3 g ammonia

1.1 g hydrogen cyanide

7.6 g of hydrogen sulfide

0.5 g organic sulfur compounds 19 g water

This gas is compressed in three stages to 8.2 ata and hydrogenated at temperatures of 380-400 ⁰ C at loads of about 2000Nur / ^mn, where a measured volume reduction of about 6 £ occurred. A cobalt-molybdenum catalyst served as the catalyst. After the hydrogenation, the heavy hydrocarbon content of the gas was only 0.1 V0I.-9%. Hydrocyanic acid and organic sulfur compounds were only present in traces.

009826/0305 * 7 -

Distance dee hydrogen sulfide from the hydrogenated gas was carried out in a known "else by passing it over lime at temperatures of 420-450 ⁰ C to 6 to β ppm.

Dae bo gate-cleaned gas was mixed with steam in the ratio of clay about 1: 0.8 and reacted over a nickel catalyst. The pressure at the inlet of the catalyst was 1.6 ata, the exit temperature of 650 ⁰ C at Feature pages of less -as a second. The gas quietly obtained in this way had the following composition *

CO ₂ 3.0 VoI, - *

CO 17.3 VcI .- *

H ₂ 75.4 vol .- *

CH ₄ 1.7 vol .- *

S ₂ 2.6 vol .- *

In relation to the coal distillation gas originally used, the increase in volume was around 100 ^. The gas still contained about 3 ppm hydrogen sulfide as well as about 180 g water and about 0.03 g ammonia per mr. The methane turnover, based on the originally available amount, was around 87 *

When splitting a coal distillation gas that has not been subjected to prior hydrogenation and also only contained 6 to 8 ppm hydrogen sulfide at the entry into the cleavage catalyst, was among the The same operating conditions only achieved a methane conversion of around 73 *.

0 0 9826/0305

- 8 Example 2

The carbon distillation agae used in Example 1 was hydrogenated as in the previous example and the hydrogen sulfide was ^{removed after the hydrogenation by passing it over a zinc oxide mass at 350 to 400 °} C. down to 2 to 4 ppm. The pre-cleaned (Jas) was mixed with steam in a ratio of about 1: 0.8 and reacted in the presence of nickel on a support material at a pressure of 8 ata and a temperature of 900 ^° G. The catalyst loading was about 1200 Hnr / m ^h · The gas obtained had the following composition!

co ₂ 3.5 VoI .- * co 16.0 VoI . - * H ₂ 76.9 VpI 0.8 VoI H 2.8 VoI

The increase in volume, based on the coal distillation gas originally used, was about 125 Jt *

In the cleavage of a non-hydrogenated carbon distillate long gas with the same sulfur content and under the same operating conditions, a temperature of 965 ^° C. was required in order to achieve a methane content of 0.8 vol .- ^ C in and gas.

Claim "

009826/0305. ₉ .

Claims (5)

. . - 9 claims 1. Process for the generation of gases rich in hydrogen and carbon oxide by catalytic splitting of carbon distillation agaaen in the presence of water vapor and optionally gases containing acid, in which the raw gases leaving the coke oven are cooled and the liquid hydrocarbons and the condensate water are separated off , characterized in that the gases are then _{compressed to a pressure of 1.5 to 30 ata t,} preferably 3 to 10 ata and ^{catalytically hydrogenated at temperatures between 250 to 700 0} C, preferably 300 to 500 ⁰ C, whereupon the gas the hydrogen sulfide is largely removed by known purification processes and, after the addition of water vapor and optionally oxygen or air, the gas is ^{continuously converted into a catalytically known gas at temperatures between 600 and 1200 0} C which is rich in hydrogen and carbon oxide * 2. The method according to claim 1, characterized in that that the compression of the cooled gases is carried out in several stages. 3 · Process according to claims 1 and 2, characterized in that that the heat of compression is removed after the individual stages in such a way that the dew point for the naphthalene still in the gas is not reached 4. The method according to claims 1 to 3 »characterized in that that before the hydrogenation one 009826 / 030S - 10 - - ίο - cooled gas contained hydrogen sulfide completely or partially removed. 5. The method according to claims 1 to 4 »characterized in that that from the cooled gas before the hydrogenation, the Maphthalin-Kohlenwasaeratoffe contained in the gas completely or partially removed. 6 · The method according to claim 5 »characterized in that that to remove the naphthalene hydrocarbons, the hydrocarbons obtained in liquid form when the raw gas is cooled used. 009826/0305