US1995647A

US1995647A - Apparatus for and improvement in carrying out chemical processes at elevated temperatures

Info

Publication number: US1995647A
Application number: US551577A
Authority: US
Inventors: Pier Mathias; Dinkler Walter
Original assignee: IG Farbenindustrie AG
Current assignee: IG Farbenindustrie AG
Priority date: 1930-07-24
Filing date: 1931-07-17
Publication date: 1935-03-26
Anticipated expiration: 1952-03-26

Description

Patented Mar. 26, 1935 APPARATUS FOR- PATENT OFFICE AND IDIPROVEMENT IN CARRYING OUT CHEMICAL PROCESSES AT ELEVATED TEMPERATURES Mathias Pier, Heidelberg, and Walter Dinkler,

Mannheim Germany, assignors to I. G. Farbenlndustrie Aktiengesellschaft,

Frankforton-the-Main, Germany No Drawing. Application July 17, 1931, Serial No. 551,577. In Germany July 24, 1930 9 Claims. (01.23-252) cially suitable are alloys containing titanium,

The present invention relates to apparatus for and improvements in carrying out chemical processes at elevated temperatures and in the presence of hydrogen.

In chemical reactions in which free hydrogen is present, either as reacting component or by formation during the reaction, such as various kinds of materials, especially in the improvement of coals of all varieties, tars, mineral oils and the like, their distillation and conversion products and carbonaceous residues, at elevated temperatures such as cracking operations, especially in the presence of added'hydrogen or gases supplying hydrogen and under pressure, such as the destructive hydrogenation or the puriiication from sulphur with hydrogen at such elevated temperatures and pressures that no substantial splitting of the materials under treatment occurs, or in the synthesis of ammonia, it is very difllcult to find suitable constructional materials which are physically and chemically sufliciently resistant, especially to hydrogen and, if present, to sulphur, at the temperatures and pressures employed. Thus iron is decarbonized by hydrogen and becomes brittle after use for a short period of time. In particular, iron walls which have to bear pressure are readily destroyed by the action of hydrogen so that either the walls must be kept cold or they must be constructed of highly alloyed steels. Furthermore, in many cases iron has an injurious effect on the course of the reaction,for example by causing side re- -'actions, such as abundant formation of hydrocarbon gases, deposition of coke or formation of undesirable polymerization products in destructive hydrogenation or cracking processes which reactions have a detrimental effect on the economy of the process. Moreover, there are only a very few materials, and these are not sufliciently available to render their general application economical, which are in any degree stable to sulphur and sulphur compounds, especially hydrogen sulphide.

We have now found that titanium alloys which contain aluminium, copper, cobalt ornickel or several of these metals, and, if desired, iron in addition to one or'more of the said metals, constitute materials which are resistant'in every respect, so that at least some, but preferably all those parts of the apparatus which come into contact with the hot materials in the said processes may be constructed of or coated with the said alloys. The titanium content of alloys which contain iron should be from 0.1 to 15 per cent, preferably from 0.5 to per cent. Espealuminium and iron. In these alloys the content of titanium may be up to per cent, preferably from 0.5 to 3 per cent; the content of aluminium may be up to per cent, preferably from 5 to 8 per cent. With iron-titanium alloys containing cobalt, nickel or copper the content of the latter metals is preferably up to 2 per cent. In the case of titanium alloys free from iron, the cobalt, nickel or copper may be present. In this case the content of titanium in the alloys preferably ranges from 1 to 10 per cent. Even at high temperatures as for example from 300 to 500 C. and more and at high pressures, such as are employed for example in the destructive hydrogenation of carbonaceous materials, the said alloys are extremely stable to attack by carbon monoxide, hydrogen or the sulphur compounds contained in the initial materials or set free therefrom during the reaction or added to the reaction products. The alloys, especially those which contain titanium, aluminium and iron, have the great advantage contrasted with the chromium alloys hitherto proposed that even with from 2 to t per cent of titanium (which is as abundantly available as chromium) the same resistance to attack by hydrogen and sulphur compounds is attained as is attained with to per cent of chromium. Moreover there is a further metallurgical advantage in the preparation of the alloys byreason of the known deoxidizing action of titanium.

The physical and chemical properties of ,the-

corrosive alloys hitherto proposed, whereby the preparation and working up of the alloys is rendered. more simple and economical. The carbon content of the said alloys may be varied as required. Usually it varies between 0 per cent and 1.5 per cent. The higher the content of carbon the more stable to hydrogen and sulphur but also the more brittle do the said alloys become. If it is desired to employ as free as possible from carbon an iron-titanium alloy containing one of the hereinbefore defined metals it is advantageous to start with metals obtained electrolytically and from iron obtained from iron carbonyl. In many cases the preparation of the alloys is preferably carried out by fusion in vacuo or in an inert gas atmosphere or by sintering of the finely divided alloy components.

Suitable alloys are those for example having the composition: 1.5 per cent of titanium, 5 per cent of aluminium and 93.5 per cent of iron; 2 per cent of titanium, 6 per cent of aluminium, 2 per cent of silicon, 1.5 per cent of manganese and 88.5 per cent of iron; 3 per cent of titanium, 5 per cent of aluminium, 2 per cent of tungsten, 2 per cent of cobalt and 88 per cent of iron; 2 per cent of titanium, 10 per cent of aluminium and 88 per cent of iron.

The titanium alloys as hereinbefore defined have the further remarkable advantage that they do not scale off when exposed to hot gases, in particular to heating gases containing oxidizing constituents, such as oxygen or carbon dioxide. This fact is of great importance for the construction of the heat transferring devices, such as preheating tubes, which when constructed of the materials hitherto in use are very liable to scale off at the surfaces which come into contact with the heating gases.

The employment of the said alloys is of considerable importance in the treatment of coals, tars, mineral oils, their distillation and conversion products with hydrogen under pressure by destructive hydrogenation. Since the said alloys have the further practical advantage that the transfer of heat by these alloys is good, they are eminently suitable also for constructing preheaters and heat regenerators. The alloys have the further favorable property of causing practically no deposition of carbon or formation of methane, such as is readily the case for example with the usual iron alloys. They may therefore be employed with advantage in the distillation or generally for the heat treatment of carbonaceous and sulphur containing substances as for example for cracking or low temperature carbonization or in the gasification of solid or liquid carbonaceous substances and also for roasting substances containing sulphur, such as ores, or in the regeneration by heat-treatment of catalysts used in hydrogeneration or cracking processes, or when working with carbon monoxide, as for example in the preparation of metal carbonyls. The alloys may also be used advantageously as the constructional or coating materials for apparatus for other reactions in which hydrogen is employed under pressure, as for example for the synthesis of ammonia or for the catalytic reduction of the oxides of carbon.

The following examples will further illustrate the nature of this invention but the invention is not restricted to these examples.

Example 1' Mexican Panuco oil containing 4.5 per cent of sulphur is treated with hydrogen under a pressure of 200 atmospheres at a temperature of 450 C. in the presence of a catalyst consisting of equal parts of molybdic acid and zinc oxide. The parts of the apparatus which come into contact with the hot treated materials and its vapors are lined with an alloy consisting of 1.5 per cent of titanium, 6 per cent of aluminium and 92.5 per cent of iron. After use for about 3 months there is no appreciable attack on the material of the apparatus.

Example 2 A mixture of '75 per cent of hydrogen and 25 per cent of nitrogen is allowed to flow at from 500 to 550 C. under a. pressure of 200 atmospheres over an iron catalyst activated with about 10 per cent of aluminium and small amounts of potassium nitrate, in a high-pressure vessel which is lined with an alloy consisting of 1 per cent of titanium, 5 per cent of aluminium, 3 per cent of chromium and 91 per cent of iron. The eiiluent gases containing ammonia are led through a heat exchanger consisting of a bundle of tubes constructed of the said alloy. Even after use for several months the alloy employed shows no signs of attack.

What we claim is:

1. In chemical relations effected at elevated temperatures and in the presence of hydrogen the step which comprises confining the reactants by a surface consisting of an alloy of titanium containing iron and aluminium, the content of titanium ranging from .1 to 15 per cent, that of aluminium ranging from 5 to 15 per cent and the major portion of the remainder being iron.

2. In chemical reactions eflfected at elevated temperatures and in the presence of hydrogen the step which comprises confining the reactants by a surface consisting of an alloy of titanium containing iron and aluminium, in which the content of titanium ranges between 0.5 and 5 per cent, that of aluminium ranges between 5 and 8 per cent and the major portion of the remainder 15 136011.

3. In chemical reactions effected at elevated temperatures and in the presence of hydrogen the step which comprises confining the reactants. by a surface consisting of an alloy of titanium, iron and aluminium, the content of titanium ranging .from .1 to 10 per cent, that of aluminium ranging from 5 to 15 per cent and the remainder being iron.

4. In chemical reactions efiected at elevated temperatures and in the presence of hydrogen the step which comprises confining the reactants by a surface consisting of an alloy of .1 to 15 per cent of titanium, 5-15 per cent aluminium, up to 5 per cent of at least one 01 the elements chromium, tungsten, molybdenum, vanadium, silicon, manganese, tin, zinc, lead, silver and beryllium, the remainder being iron.

5. In the destructive hydogenation of a carbonaceous material the step which comprises confining the reactants by a surface consisting of an alloy of titanium, iron and aluminium, the content of titanium ranging from .1 to 15 per cent, that of aluminium ranging from 5 to 15 per cent and the remainder being iron.

6. In the synthesis of ammonia the step which comprises confining the reactants by a surface consisting of an alloy of titanium, iron, aluminium and chromium, the content of titanium ranging from .1 to 15 per cent, that of aluminium ranging from 5 to 15 per cent, that of chromium ranging from 3 to 5 per cent and the remainder being IIOll.

7. In chemical reactions eflfected at .elevated temperatures and in the presence of hydrogen the step which comprises confining the reactants by a surface consisting of an alloy of titanium, iron and aluminium in which the contents of titanium and of aluminium range between 0.1 and 10 per cent and between 5 and 8 per cent respectively and the remainder is iron.

8. In chemical reactions effected at elevated temperatures and in the presence of hydrogen the step which comprises confining the reactants by a surface consisting of an alloy of iron containing from 0.1 to 10 per cent of titanium, from 5 to 8 per cent of aluminium and up to 5 per cent of at least one of the elements chromium, tungsten, molybdenum, vanadium, silicon, manganese, tin,

5 zinc, lead, silver and beryllium the remainder being iron.

9. Apparatus for carrying out chemical reactions at elevated temperatures and in the presence of hydrogen, in which the inner surfaces of the walls exposed to the reacting materials are at least in part composed of an alloy containing titanium, iron and aluminium, the titanium content ranging from .1 to 10% and the aluminium content ranging from 5 to 15% of such alloy of titanium and the major portion of the remainder being iron.

MATHIAS PIER. WALTER DINIGJER.