US2054776A - Conversion of carbonaceous materials - Google Patents

Description

Patented Sept. l5, 1936 coNvEnsIoN or cAanoNA'cEoUs MATERIALS Mathias Pier, Heidelberg, Bruno Engel, Mannheim, and Walter Kroenig, Ludwigshafen-onthe-Rhine, Germany, assignors to Standard` I. G. Company, Linden. N. J., a. corporation of- Delaware Application August is, 193e, semina. 685,229

In Germany August 26, 1932 2 Claims. (Cl. 196-53) The present invention relates to improvements in the treatmentwith hydrogenating gases of carbonaceous materials containing or giving rise to the formation of asphalt to produce valuable' 5 hydrocarbon products and in particular to an advantageous manner of adding catalysts to the reagents.

The drawing represents in diagrammatic form an apparatus suitable for carrying out the invention.

In the conversion by heat of carbonaceous materials comprising asphalt, i. e. containing or giving rise to the formation of asphalt, such as coals vmade into' pastes with oils or oils containing asphalt, in particular in the presence of hydrogenating gases, and more especially in the destructive hydrogenation of said materials, cata--4 lysts have hitherto been added thereto before their entry into the apparatus, the mixture then being brought to the reaction temperature in a preheater. In this process it was observed that during the heating the high molecular asphaltlike constituents of the initial materials penetrate into the pores of the catalyst and thus impair its activity already at the beginning of the reaction. Furthermore the small particles of catalyst become stuck together by the asphalt forming larger particles, which then settle inan undesirable manner. The catalysis thereby suffers owing to the resulting absence in the reaction space of active catalyst due to the setting of large amounts of stuck catalyst which is therefore wasted. The said conglomeration of catalyst may in some .cases even take place when a suspension prepared by grinding the catalyst with an oil containing asphalt is allowed to stand for some time while hot.

We have now found that the disadvantages hereinbefore mentioned are avoided by dispers- 40 ing the catalyst in the absence of asphalt in an oil which is freefrom asphalt and which when mixed with the carbonaceous material to be treated. or the vproducts lformed. therefrom does not cause fiocculation of the asphalt present or formed during the working up and then adding the suspension to the initial material to be treated or undergoing treatment. The term "dispersing" includes suspending or making up into a paste. By the expression "oils not causing flocculation of asphalt we mean either oils which do not cause fiocculation even when added in large quantities or oils employed in such amounts as do not cause fiocculation though larger amounts thereof are capable of causing fiocculation. Thus for .example also a middle or heavy oil consisting of 5 'a large proportion of saturated hydrocarbons may be employed if it is added in but, so small quantities that no iiocculation takes place. By asphalts we understand substances which are chemically similar to natural asphalt and which 10 represent black brown, solidor vsemi-solid high molecular hydrocarbon compounds containing oxygen and in most cases also sulphur, which are dissolved or suspended in mineral oils or other liquid hydrocarbon products such as prod- 15 ucts obtained by the destructive hydrogenation of carbonaceous materials and which may in part be precipitated from the said liquid hydrocarbon products4 by benzine and in part from their. solution in ether by addition of alcohol (see Holde 20 Kohlenwasserstoffl'e und Fette, 1933, page 164) The present invention is of particular advantage in processes in which the catalyst dispersion in oil is admixed with the initial materials prior to any heating or preheating necessary to bring 25 them to the reaction temperature. The said heating is preferably carried out with an addition of a hydrogenating gas such as hydrogen.

By stating that the dispersion o! the catalyst in an-oil free from asphalt should take place in $0 the absence of asphalt we wish` to exclude a treatment in which the catalyst is flrst contacted with an asphalt-containing oil and then further distributed in another oil which may be free from asphalt; since this procedure would result in the preparation of a catalyst which is soon clogged up with asphalte. The pre-treatment of the catalyst in the absence of asphalt with an oil free from asphalt has the result that the capacity of the catalyst for adsorption is practically com- 40 pletely used up by the oil free from asphalt, so that the catalyst, for'example during its heating up together with the initial materialfhas practically no adsorptive capacity for the asphaltic constituents, although the invention is not limited by this 45 theory. It is preferable to add the suspension of the catalyst in the oil free from asphalt to the oil containing asphaltV which is to be worked up, at a time which is not too long before the working up, because when the mixture is allowed to stand 6e fora very long period of time an exchange between the oil free from asphalt on the surface of the catalyst and the oil containing asphalt commences to take place.

For the purposes of the present invention an oil is considered to be free from asphalt, if it is entirely or practically free therefrom that is to say, if it does not contain asphalt in amounts above 0.5 per cent and preferably not above 0.3 per cent by Weight. The amount of asphalt contained in the oil as dened in the present specification is determined as follows: 2 grams of oil are mixed with 5 cubic centimeters of benzene and 100 cubic centimeters of normal benzine, and allowed to stand for 12 hours. The asphalt which precipitates'y out is lfiltered oi, washed on the lter with normal benzine and dissolved in benzene. The benzene is evaporated oir, and the residual asphalt is dried and weighed. As oils free from asphalt may be mentioned middle oils or heavy ollsanswering to said specication and it is particularly advantageous to employ a heavy oil answering to said specicationsv obtained by destructive hydrogenation from the initial materials to be worked up. Thus middle oils 0r heavy oils obtained by the destructive hydrogenation of mineral coals or mineral coal tars are of advantage as oils free from asphalts to be pasted up with the nely divided. catalysts. Also frac tions of these tars themselves are suitable for this purpose. `As further examples of such oils may be mentioned anthracene oil free from asphalt or oils, preferably of middle oil boiling point range,

obtained by the destructive hydrogenation of carbonaceous materials at temperatures of the upper half of the temperature range suitable for this reaction, whereby a high content oi' aromatic hydrocarbons is imparted to the final products. Also naphthenic or paraiiinic base oils come into question, the latter being employed in such smallV quantities that no flocculation takes place. It is of advantage to select an oil as dispersing medium which has a gravity of the order of the catalyst to be dispersed or previously to intimately mix the 2 catalyst to be dispersed in theoil with a solid vsubstance which adapts the gravity of the solid mixture to that of the oil in which it is to be dispersed.

v'Ihese oils, when not added in restricted amounts, should notcontain so much aliphaticconstituents rich in hydrogen that there is any danger when mixing these v'oils with an asphalt containing oil that a fiocculation of the asphalt which would lead to clogging of the apparatus, occurs. As a rule not more than 20 per cent, preferably less than l5 per cent, of aliphatic constituents rich in hydrogen reckoned on the initial material comprising asphalt should be added to the latter.

'Ihe invention is of particular importance for working up tars or mineral oils containing asphalt,

ly treated in accordance with the present invenf tion.

As catalysts may be mentioned those having a hydrogenation action, especially metals, or their compounds, of the 2nd tothe 8th group of the periodic system, as foriexample zinc, magnesium,

cadmium, boron, titanium, tin, lead, vanadium,

manganese, i'ron, cobalt, rhenium and especially those of the 6th group, such as chromium, molybdenum, tungsten 'and uranium. Advantageous y compounds are oxides and sulphides. The catachloride dissolved in naphthenic acidvor oleic acid,

may be employed. The catalytic material may l also be brought on to the carrier substance while it is in a colloidal state oi' dispersion.

The expression treatment by heat, preferably with hydrogenating gases where herein employed is intended to comprise the most various reactions. The said treatment may be used to produce hydrocarbons of all sorts by cracking or by. destructive hydrogenation, such as motor fuels, middle oils, kerosene and lubricating oils. The said expression also includes the removal of nonhydrocarbon impurities, n such as sulphuror oxygen-containing substances or nitrogen compounds by the action of hydrogen or gases containing or supplying hydrogen from crude carbonaceous materials containing or giving rise to asphalt, for example the refining by treatment with hydrogen of crude goenzolcontaining asphalt, of crude motor fuels or of lubricating oils, containing or giving rise to asphalt. 'I'he said expression further includes the conversion of oxygen or sulphur containing organic compounds containing or giving rise to asphalts to produce the corresponding hydrocarbons or hydrogenated hydrocarbons, for example the conversion of phenols or cresols containing asphaltic substances into the correasphalt and more particularly of unsaturated hydrocarbons of said'nature or of aromatic compounds containing asphalt and more particularly of aromatic hydrocarbons of said nature, for example, to produce hydroaromatic hydrocarbons.

'I'he said reactions by heat treatment, especially with hydrogen or hydrogen containing gases, are effected in the liquid phase and usually carried out at temperatures between 250 and 700 C., usually between 300 and 700 C. and more preferably between 380 and 550 C.l The pressures employed may be atmospheric or superatmospheric; they are preferably in excess of 20 atmospheres and more advantageously in excess of 50 atmospheres. n some reactions, however,

' for example, in the reiining of crude benzol containing asphalt, rather low pressures, for example, of the order of 40 atmospheres may be employed. Generally, however, pressures of about 100, 200, 300, 500 and in some cases even 1000 atmospheres come into question.

'I'he amount of hydrogen maintained in the reaction space and parts connected therewith, ii' any, varies greatly with the nature of the particular initial materials treated or according to the result in view. In general 400, 600, 1000 cubic meters or more of hydrogen, measured under normal conditions of temperature and pressure, per

ton ofcarbonaceous material treated may be used. It is particularly advantageous to operate by continuously introducing fresh carbonaceous inaterial into the reaction vessel and to continuously remove products Itherefrom. If desired several reaction vessels may be employed in which different conditions of temperature and/or pressure may, if necessary, be maintained and in which different catalysts may also be employed. Sulciently converted reaction products may be removed behind any of the reaction vessels. Mai terials which have not been suiilciently reacted on may be recycled or treated in a further reaction vessel. The subsequent stages may, if desiredkbe carried out in the gaseous phase, for example to produce anti-knock motor fuels. One of the subsequent stages may also take the form of a cracking. I

Referring to the drawing, numeral I indicates a. -tank in which a catalyst is'produced-either in solution or in suspended form, as seems desirable. Line 2 conducts this solution or suspension into a mixing chamber 3- into which a carrier material may be placed. The mixing device is fitted with a stirring mechanism and air is injected by means of a line 5 into the catalyst in order to spray the solution or suspension over the carrier material. e

The mixing device is also fitted with a chute 6 for discharging ,the catalyst after it has been produced in a dry form into a mixing chamber 1. Asphalt free oil of the types mentioned above, such as anthracene oil, is fed into th mixing chamber from aA storage vessel 0a and this mixture is then passed into a disintegrator AA pump 9 may be utilized to pass the material discharged from the disintegrator back to the mixing chamber by pipe I0 in order to gain uniformity and a portion thereof may be drawn oil by a vpipe II and discharged into a second mixing chamber I2 which is also tted with a stirrer I3 and into which a main body4 of the oil to be subjected to the hydrogenating treatment is conducted by aline I4 from storage I5. The admixture of the three ingredients, namely the catalyst, the asphalt free oil and the oil to be treated, is then passed by a line I0 and pump I1 to a preheater I8. Hydrogen is introduced preferably into the inlet of the preheater by means of a pipe I9 and the preheated mixture is passed into a reaction' chamber 20. The reaction products may be withdrawn from the top of the reaction chamber by a line 2I and discharged into a separating vessel 22. Liquid and solid materials can be withdrawn by pipe 23 while the vapors pass overhead by a pipe 24 to a condenser 25 and a separating vessel 26 from which gases are removed by 21 and the liquefied product by 28.

CThe expression hydrogenating gases" means, where herein employed, hydrogen alone or gases containing or supplying hydrogen, for example a mixture of hydrogen with nitrogen, or water gas,

Advantageously so much of the 4Vcatalyst dispersion is admixed lwith the carbonaceous material that the nal mixture'contains between 0.05

and 5 per cent by weight and preferably between not restricted to these examples.

Example 1 Brown coal small coke which has been activated with steam at 900 C. is impregnated with an ammoniacal solution of molybdic acid sothat the coke contains 2 per cent bf molybdic acid. The catalyst thus prepared is then ground to colloidal fineness in a percussion cross mill and mixed with such an amount of-a heavy oil free from asphalt (obtained as hereinafter described) that a suspension containing 30 percentvof catalyst isyobtained. This mixture of oil and catalyst has added thereto a German petroleum boiling above 325 C. and containing asphaltl so that the latter contains 1 per cent of catalyst. The mixture is then heated'to 475 C. with hydrogen under a pressure of 200 atmospheres andrled throug a reaction vessel; 1650 cubic meters of hydroge are used for each metric ton of oil.A The pro ucts leaving the reaction vessel are led into a separating vessel kept` at 460 C. in which a liquid level is maintained.' From the bottom of the vessel are withdrawn 6 per cent (calculated with reference to the treated material) of high boiling products containing catalyst, while the remainder of the reaction products together with the hydrogen are suppliedto a fractionating coiumn. From this column aire obtainedA 55 per cent of constituents boiling up to 325 C., which conv sist of 27 per cent of benzine and 73 per cent of middle oil, and 45 per centof constituents boiling above 325 C. which are free from asphalt. A part of the latter are employed, as already mentioned, for mixing with the catalyst. The remainder may be supplied to the same or another reaction vessel for further conversion into constituents of lower boiling point.

If the catalyst is directly added to the asphaltic initial oil to be converted the catalyst particles become soon stuck together and the catalyst deposits in substantial 'quantities in the preheater and in the reaction vessel, whereby inconveniences such as a decrease in the activity of the catalyst, a decrease of the volume of the reaction space and a clogging up of the preheating coils are encountered after some time oi operation.

Example 2 Active carbon is impregnated with 5 per cent of zinc chloride and then mixed with a'lubricating oil, f ree from asphalt, obtained from a German mineral cil by distillation or by destructive hydrogenation in such an amount that a suspension containing 30 per cent of catalyst is formed. This suspension is thereupon added to an oil fraction containing asphalt and boiling above 325 C. which is obtained from a German mineral oil, in such an amount that the mixture contains 1 per cent of catalyst. This mixture is then heated in a heating tubey system under a pressure of 50 atmospheres to 485 C. and subsequently passed through a cracking space connected with said tube system and having a greater diameter than the tubes of this system. In this manner benzine is obtained in a yield of 42.8 per cent with reference to the initial asphalt containing oil. 'If the catalyst is directly added to this oil the inconveniences described in Example 1 are encountered.

What we claim iszl 1. In a process of destructive hydrogenation of carbonaceous materials rich in asphalts or substances which produce asphalt during the treatment, the steps of first dispersing a nely divided catalytic material in an oil free from asphalt and which when mixed with the carbonaceous material to be treated or the product formed therefrom does not cause flocculation'of asphalt iniaoume Y tially present or formed during the process to form a paste containing 10 to 60% of catalyst, adding the suspension thus formed to the carbonaceous material to be treated, to form a mixture containing from .05 to 5% of catalyst, and then subjecting the mixture to destructive hydrogenation.

2. Process according to claim '1 in which the proportion o! the catalyst is` .1 to 1.5% ofthe oil mixture.

MATHIAS PIER. BRUNO ENGEL. WALTER KROENIG.

Images