US2012318A - Process of hydrogenating carbonaceous materials - Google Patents

Description

Aug. 27, 1935. r. w, PFIRRMANN 2,012,318

PROCESS 0F HYDROGENATING GARBONACEOUS MATERIALS Filed Aug. 5, 1955 Patented Aug. 12 7, 193,5, t

"UNITEDFSTATES PATENT oFFlcE annals mocnss oF-nrnaoGnNAmG cAnnoNacaoUs MATERIALS Theodor Wilhelm Pilrrmann, CastropRauxel,

Applicaid: :August s, 1933, 'serm No. $113,9094

Germany .August 10,1932 (G51M-53.)"-

My invention refers to theA treatment of car-l bonaceous materials and more especiallyl to` 'a treatment whereby solid o'r liquid materials of the kind referred to which boil at higher templratures are converted into products of higher v ue.

My invention is a modication of the process disclosed in a copending application for patent of the United States filed by Richard Bayer on September 21, 1929, Serial No. 394,393, cording to which liquid products are producedm solid or liquid carbonaceous materials by bjecting same at -high temperatures and high pressure in o an autoclave to the action oi' nascent hydrogen developed by the interaction of water and finely subdivided -(spongy) iron admixed to the mate-4,

rials under treatment. In this process the ferr-lc oxide resulting 'in the reaction, after having been removed from the reaction vessel, -is reduced again to metallic iron withv the aid-of reducing gases, the metallic iron being reintroduced into the reaction.

Iron appeared to be the onlyy metal allowing the process to be carried out in a commercial manner, since ,iron isjreadily reduceable and' on such reduction is obtained `in pulverulent,A i

spongyv condition requiring no further comminution and allowing the reaction mixture to 'be conveyed by pumping, while other metals ca` pable of reacting with water underformation of nascent hydrogen at a sufficiently high reaction velocity are either notl reduceable at all or only with difficulty, or, if reduced, form compact masses which require comminution by mechanical means. Experience moreover showed that ,fnetals comminuted in such-manner showeda tendency vto clogging the pipes; the pumps being moreover Worn down-by them'in a short time.

Contrary to theseV assumptions I haveV now found that the processof hydrogenating carbc. naceous matter in'the manner-above described. can also be carried out in a' simple and very efilcient manner withjzincfmet'alinstead of the iron hitherto used, providedonlythat the zinc I oxide forming in' therea'ction is'reduced in such manner .that the `metallic zinc formed by reduction is obtainediiij very fine" subdivision.

While it is well to redic zinc oxide and zinc ores by means of solid carbon, such reduction with gases containing oxygen, even in combined form, such as water-gas, which contains carbon monoxide or hydrogen, is not feasi- A ible since in this reaction carbon' dioxide or water are formed which react at once withjthe nely subdivided zinc .under formation of zinc oxide.

ypour is present to ca I have nw round that zinc oxide can be reduced with great advantage. besides with lsolid carbon, alsowith hydrocarbons, such as methane `or vits higher homologues or with liquidhydrocarbonsin the vapour phase, if a temperature of -5 about 1000 is maintained.. Y If the zinc'oxide is reduced with the aiduof c. suchvapours.l more especially if these vapours are present in excess' of the stoichiometric quantity, the resulting metallic zinc is obtained not in ,solid form, but in the form of nely subdivided zinc powder, which can4 beemployedv directly in the hydrogenation process described above,`

Vsince it can readily be forced by pumping into the reaction vessel together with the oil and water. 4

It is, however, also possible to. reduce the zinc oxide with the 'aid of solid carbon, provided that some .gaseous hydrocarbon or hydrocarbon vany away the dlstimng zinc in theiorm of a fine powder.

The hydrogenation reaction employing zinc as reagent with water to develop hydrogen occurs4 according' to the equation -where less than the molecular quantity of zinc is employed.A VI have found that in some cases the reaction between the zinc andthe water must feven be retarded, and in these cases I prefer using only `the molecular quantity, or -even less, of Y water, adding the water (successively) at differentpoints of the reaction system.

A4 further advantage offered by the useV of zinc as compared with. iron consists therein that zinc does notfavour the formation of methane. In

` other words less ofthe oil under treatment is con@ verted into gases so that theyield of hydrocarbons is4 higher than if iron is used in the raction.

Equally as with the iron valso zincfallows operating with sulphur containing materials and in this case the products obtained are almost free from sulphur, part of the sulphur being in this I case combined in the form of zinc sulphide, which on being regenerated does not become volatile and may be converted by oxidation into zinc oxide and is returned into the process.

'I'he hydrogenation with zinc is particularly suitable in the case where solid carbonaceous materials such as pitcoal, lignite and the like shall be combined with hydrogen. If the reaction is carried through with iron, theiron must be separated from the ashes contained. in the raw material by subsequent treatment. When zinc is used, however, the oxide which remains in the residue or ash after thehydrogenation'reaction may be reduced under high temperature conditions so that metallic zinc is volatilized. Such zinc is carried away by the gases in metallic form as a vapour and is recovered by condensation in pure condition as a powder, while the residues are substantially freed from Zinc.

When using the equivalent quantity of water, up to 99% of the zinc are converted into Zinc oxide. In certain cases' it may prove useful to employ water in excess of the calculated quantity, since the water in excess replaces a certain percentage of the oil in the solid material so that the excess of water is present in the'zinc oxide, while the oil is easily available in liquid form. Instead of providing an excess of water in the reaction vessel from the beginning, it may also be subsequently added to the-hydrogenation mixture and in this case the oil is also displaced from the zinc oxide.

The drawing is a flow sheet illustrating the process.

In practising my invention proceed as folloWs:-

Example 1 100 parts by weight of a finely ground bituminous coal are forced by pumping together with 120 parts zinc powder, 40 parts Water and 100 parts brown coal tar, serving as a carrier, into a pressure-resistive reaction vessel equipped with an agitator and heated to a temperature of about 450 C., the pressure within the vessel being maintained at about 250 atms. The reacted mixture travels through the reaction vessel and after leaving it is passed through a heat exchanging device. of the bituminous matter are thus converted into liquid oils, about 25% of which may be used as liquid fuel, while the rest boiling between 220 and 360 C. can be used either as a fuel for Diesel engines, or for heating purposes or may be employed as starting material for the manufacture of lubricating oils, or it may be returned into the process together with fresh coal.

In a similar manner comminuted Wood can be hydrogenated, the wood substance being converted completely into oil. From parts airdried wood about 50 parts of an oil were obtained.

The gases'leaving the reaction vesselcontain only from 5-10% hydrogen, the rest being methane, to which some ethane is admixed. The zinc oxidecontained in the residue together with carbon and ashes is heated to about 1000 C. in

I may for instance a vertical step-grate furnace together with a corresponding quantity of untreated coal, methane being at the same time introduced in to the fur- Example 2 A mixture of 10 parts by weight brown coal tar oil boiling above 250 C. and containing up to 5% sulphur with 10 parts zinc powder and 3.5 parts water, which may contain a few per cent soda or potash, is heated in a reaction vessel to about 455 C., the pressure rising to about 350 atms. About 102% by volume of a comparatively low boiling oil are obtained, which contains less than 0.1% sulphur, 42% boiling up to 180 C., further 30% between 180 and 220 C. The rest vmay be once more subjected to hydrogenation or utilized as liquid fuel or as a starting material for the manufacture of a lubricating oil. The zinc oxide resulting in the reaction is reduced to zinc powder with the equivalent quantity, or more of methane.

Similar results are obtained with a tar produced from lignite. The phenols of the tar are converted to the greater part into aromatic hydrocarbons. Thus for instance a brown coal tar containing 85% phenols, after having been subjected to hydrogenation at 475 C. only contained about 9% phenols. The fraction still containing phenols may be re-introduced into the process so that practically a nols may be obtained.

If raw materials are treated which do not readily lend themselves to hydrogenation, a specic hydrgenation catalyst may be added and in this case, instead of alkalis, chromium, chromium salts, molybdenum compounds' or the like may be added in watery solution.

. added and the solution is diluted to such an extent as to contain 5% molybdenum. This solution may be .used in the process as described and in place of the. soda solution, referred to in Example 2. In this form of the process the known hydrogenation catalysts are enabled to act in molecular solution, i. e. in an extreme grade of subdivision.

Zinc has proved to be particularly useful in the hydrogenation of crude oils (petroleum) since in the oil districts the methane and other hydrocarbons required for` its reduction are available in great quantities; the natural gas available in these districts can be used directly for regenerating the zinc oxide. y

Natural emulsions of crude oils, which on account of the water content are diiiicult or impossible to treat, may be hydrogenated according to the present process with zinc and water to great advantage.

The residues from the cracking processes may also be reacted in this manner, for instance 100 parts by weight of cracking residues of crude oil of 300 C. initial boiling point, being subjected to treatment for hydrogenation with 100 parts zinc and 28 parts water at about 450 C. and a. pressure of about 400 atms. The resulting-product, of which about 102% by volume are obtained, consists of about 38 parts by volume complete reduction of the phe-l gasoline and 25 parts'by volume petroleum, the

2,012,818 vmetal is oxidized and the hydrogen reacts with wise'have to be treated with acid. In the hydrogenation procedure according to the present process the presence of sulphuris not interfering with the reaction, on the contrary it favours the hydrogenation reaction. In the reduction process, however, sulphur is an undesirable substance since zinc sulphide is not being reduced to metallic zinc and does not act as a hydrogen supplier. Therefore, when treating highly sulphurous initial materials the formed zinc sulphide will be reduced to zinc oxide-wholly or 'partly before undergoing'the reduction, by means of a roasting process. The extent of removing the sulphur in the roasting process depends on the initial materials.

The hydrogenation by the interaction oi metal and water proceeds the better, the higher the pressure. In proportion to the degree of lling ot the reaction vessel the pressure in the vessel rises, and the percentage of liquid required for conveying the zinc,` through the vessel increases correspondingly. Thereforel the capacity o! a given reaction space rises considerably in proportion-to the rising pressure since the time, duringwhich the substances remain in the reaction vessel, rises in'proportion to the degree of filling of the vessel. First of all, however, the undesirable formation of hydrocarbon gas, such as methane, is greatly reduced as the pressure rises, and the yield of liquid hydrogenation products is increased. Since the production ofA the high pressure, as compared with processes operating with hydrogen compressed by mechanical means, can be eiIected in this process by simple liquid pumps -without requiring considerable energy, pressures of 500 atms. and above can be used in actual practice.

'I'he substances to be reacted vmay be introduced into the reaction vessel either singly or mixed with each other, or the zinc powder may be either admixed to the water or to the oil. Anagitator in the reaction vessel -will intimately mix the substances. f

Since, when forming the hydrogen by interaction of 'zinc and water, considerable quantities of heat are liberated, it is preferable to introduce the zinc and/or. the water into the reaction vessel not at one point but at several dis'- tant points to provide for a better distribution of the heat.

The reaction vessel may be arranged vertically or horizontally and the water may be conveyed in equal current or in countercurrent to.

the zinc and to the materials to be hydrogenated.

Various changes may be disclosed in the foregoing specification without departing from the invention or sacricing the advantages thereof.

I claimz- 1. In a processv of treating solid andliquid carbonaceous materials by heating such materials in a closed container with water and va lmetal under conditions such thatvthe water is.

decomposed by the metal to form hydrogen, the

' tion catalyst.

made in the .details the carbonaceous materials to form liquid products and a residue containing the metal oxide, the improvement which comprises using zinc powder as said metal, separating the zinc oxidecontaining residue formed by the reaction from said liquid products, subjecting the oxide-containing residue to the action of reducing gases under conditions such that metallic zinc is vaporized, condensing and recovering metallic zinc from the vapors in the form of ne powder and returning the powder for use as the metal in said process.

J2. In a process of treatingsolid and liquid carbonaceous materials by heating such materials with water and a metal under conditions such that the water is decomposed by the metal to form hydrogen, the metal is oxidized and the hydrogen reacts with the carbonaceous materials to' form liquid and gaseous products, the

improvements which comprise using zinc powder as said metal, separately recovering said gaseous products, said liquid products and the zinc oxide- .containing residue formed during the reaction reducing the zinc oxide in said oxide-containing residue by subjecting it to the action of vsaid gaseous products while heating above the volatilizationI temperature of metallic zinc whereby denum compound is present during heating of said materials with said metal and water, said molybdenum compound acting as ahydrogena- 5. Ina process of treating solid. and liquid carbonaceousmaterials containing sulphur by heating such materials with water and a metal under conditions such that the water is decomposed by the metal to form hydrogen, the metal forms a sulphide and hydrogen reacts with said carbonaceous materials to form liquid and gaseous products and a metal sulphide-containing residue, the improvement which comprises using zinc powder as said metal, separately recovering the gaseous and liquid products as well as the zinc sulpliide-containing residue, roasting the residue to form zinc oxide therein andl subsequently reducing the zinc oxide-containingA residue by subjecting it to the action of said gaseous products whileV heating above the vaporization temperature of metallic zinc, condensing metallic zinc vapors and recovering the zinc 1n the form of a line powder and returning the powder for subsequent use as the metal in said process.

THEODOR PFIRRMANN.

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