DE2226086C3 - Process for the production of heating gas with a calorific value of at least 9500 kcal / Nm to the power of 3 - Google Patents

Description

30th

The invention relates to a process for the production of heating gas containing methane and ethane as the main components and having a calorific value of at least 9500 kcal / Nm ''. in which a hydrocarbon with at least 3 carbon atoms and a boiling point of not higher than 150 ° C. is brought together with hydrogen in the gaseous phase in the presence of a catalyst at a temperature between 150 and 400 ° C. as a starting mixture.

With a heating gas, e.g. B. town gas, which has to be transported in lines over long distances. it is desirable that the greatest possible amount of heat is obtained from the gas for the advantageous use of the pipe system. In recent years it has become necessary to use so-called synthetic natural gas on a large scale, that is to say, synthetically hf- ordered gas with an equally high calorific value wi. Natural gas. In the case of a heating gas containing methane as the main component, the calorific value is insufficient for this requirement, since pure methane has a relatively low calorific value of about 9500 kcal / Nm ³ . On the other hand, heating gases with a high calorific value, such as. B. propane or butane, cannot be used as town gas conveyed through pipes under pressure, since they condense out at least partially. Therefore, the aim is for the heating gas to contain methane as the main components in combination with ethane, which does not condense and has a higher calorific value than methane.

However, by conventional methods, it is difficult to obtain such high quality heating gas without extremely to obtain complicated process steps, so that so far no process which fully meets these requirements was developed.

Fs is well known. Hydrocarbons with not less than 3 carbon atoms, such as. Ii. Liquid gas, to a heating gas by thermal (. 'nod. Steam reforming or hydrocracking. In the thermal cracking and the Inoculation reforming processes, however, it is impossible to to obtain a heating gas of very high calorific value, since the starting hydrocarbons are selectively converted into methane be transferred, which is essentially free of Ethane is.

The known hydrocracking plants are divided into catalytic /; and in non-alkaline hydrocracking processes. Of these processes, the latter is -for the production of mainly methane im -J Älhan containing heating gas is suitable. In this method, however, the reaction proceeds at an increased Pressure of at least 20 atmospheres and at an elevated temperature of 700 C or higher so that full sales are achieved. However, such high temperatures and pressures inevitably result for the undesired deposition of carbonaceous substances, especially when the Hydrocrackreaklion takes place in the presence of a high excess of hydrogen. As a result, the Yield of heating gas and difficulties arise in the plant and in the individual process stages In addition, the use of a large excess amount of hydrogen requires a large amount of unreacted hydrogen in the heating gas, which lowers the calorific value of the gas. There is therefore a need to provide a further process stage for separating the hydrogen from the gas, to achieve the desired calorific value.

Of the above-mentioned catalytic hydrocracking processes, two processes in particular are known, wherein in the one relatively high-boiling hydrocarbons, such as. B. Kerosene or viscous petroleum product, are converted into lower-boiling hydrocarbons and the other relatively low-boiling Hydrocarbons such as B. liquid gas or light oil, in the presence of a catalyst in methane be converted (GB-PS 1158 356). The first method uses a sulphide of nickel, cobalt. Molybdenum or tungsten used as a catalyst, but if a lower hydrocarbon than If propane is to be produced directly, it is necessary to maintain a high temperature of at least 500 C, at which carbonaceous substances develop the same disadvantage occurs that also occurs in non-catalytic hydrocracking processes. In the latter case, however, (GB-PS! I 58 356) relatively low-boiling hydrocarbons in methane in the presence of a nickel catalyst and a relatively low temperature of 150 to 400 ° C. With this one However, almost only methane is produced in the process, so that a heating gas with the required high calorific value does not exist is available. This method also requires a substantial excess of hydrogen with an H / C atomic ratio above 4: 1 to ensure high conversion, whereby the resulting heating gas has a relatively large amount of non-reactive hydrogen and this reduces the calorific value of the gas if it is not deposited in a further process stage will. The high nickel content of the The catalyst used in the known process promoted the hydrocracking process. but must

your

minien WiisserstoffUbcrschuß _iv ge _n cine unwanted carbon

Avoid "" ί, 'ήΐΊι.ιηιζ / u.
_r jscneio "'' t... Dnmprrcformiervcrfahrcn / um

^ΛΠ ί'η vc Koblenwassersloffen mil water vapor ^to secure i '"alz of about" hydrogen loading, uiiter "^ ¹¹ PS, 0 85 947), in which a catalyst. ^kannl ID cards contain 5 to 20% nickel oxide and 10 to ^{the V} SybSoxid on a carrier, ve, -Ί ,. ^{and mixtures of mainly alcohol} and carbon monoxide as well as some carbon, methane, water vapor and nitrogen. which do not represent high-quality heating gases

^ste Jl ^Cn 'p _r rindun "is an object that turns i _S Z SnmSVerfahren to design so that the Target as the main components methane and Alhan! fha end fuel gas with a calorific value of in.ndeosoo kcal / Nm ³ in a simple manner a ge _ri ^C "eÄmverhä.lnis of hydrogen to carbon ₂ o

, Iff is available in the starting mixture. ^le η _e e Auae is characterized according to the invention overall, ··, ^ H Toggle the catalyst on a solid support ^1O _e ordnts molybdenum oxide "knitted percent ^S 70 and at least one of the _folgen-": ° "in an amount of 10 b" lr , _m \;,. h nickel oxide, cobalt oxide, chromium

its saturation consumed and its low! will. Particularly suitable f "" - "'"·;"^ stolTc are saturated aliphatic carbons oje with 3 to 9 carbon atoms. Koh Icwnsscn, toHe with a boiling point of more than ® <*** §}?" should not be used, since then carbon-rich substances are formed which reduce the amount of Hu / -ta and the activity of the Kahily used

over

special-

ipeifienen catalysts Athan sdekiiv in lion with methane is produced. wöbe, one with a high calorific value of more than cal / Nm ^{3 is} easily achieved. The proportion of San ^ and the butane in the generated fuel gas is? Decreased by ^P n HPTR chllichen value so that no Sdensa.ton And entering the transport if Α "is used is city gas, after it has been diluted with other gaseous fuels

'' '' the reaction in the case of «ner-

equally gciui _& w,,

using a lesser wasseiMuimim, ..., than the conventional hydrocracking process, so the process works as well how to simplify the system for carrying out the process. Since the hydrogen content is reduced and the If the proportion of ethane is increased, it becomes a heating gas of high calorific value without the need for hydrogen separation received in a separate procedural stage.

In the invention, the starting hydrocarbons are those of at least 3 carbon atoms and a boiling point of not more than 150 C. Such hydrocarbons contain saturated aliphatic Hydrocarbons, saturated alicyclic hydrocarbons and aromatic hydrocarbons. Examples of hydrocarbons are propane. Butane. Hexane, cyclohexane, benzene, toluene, mixtures thereof, LPG and petrol fractions. These hydrocarbons can either be used individually or as Mixtures can be used with each other.

Although unsaturated aliphatic hydrocarbons can also be used, they are not necessarily advantageous for the process according to the invention, since acr hydrogen in this reaction / u

(-11IHViVm ^ MV ..-,. ,,.

about hydrocarbons ir.
specified catalysts
Preferred catalysts contain

it) molybdenum oxide and nickel oxide,

b) molybdenum oxide, nickel oxide and cobalt oxide.

c) molybdenum oxide. Nickel oxide and chromium oxide.

The most beneficial catalyst contains molybdenum oxide and nickel oxide. The proportion of molybdenum oxide on the carrier is in the range from 10 to 70 percent by weight, based on the weight of the solid support. If the molybdenum oxide content is less than Is 10 percent by weight, the catalytic activity decreases and the reaction cannot be carried out with an

; Reaching efficiency can be carried out. With a proportion of more than 70 percent by weight don't get better results. The preferred molybdenum oxide content is in the range from 14 to 32 percent by weight, based on the carrier weight. The proportion of nickel oxide held by the solid support, Cobalt oxide and chromium oxide range from 3 to 15 weight percent based on weight of the solid support. If the proportion of the above metal oxides falls below 3 percent by weight, the catalytic activity lower, whereas an increased proportion of more than 15 percent by weight increases an increase in methane production and a decrease in ethane. The preferred one The range of these metal oxides is between 4 and 10 percent by weight, based on the carrier weight. The ratio of molybdenum oxide to at least one of the oxides of nickel, cobalt and chromium can be varied within the limits given above, but the use of the latter Metal oxides in the range from 9 to 60 percent by weight, based on the weight of the molybdenum oxide, is preferred. The most favorable ratio is in the range from 15 to 30 percent by weight.

The solid support on which the above metal oxides are arranged, contains various solid substances that are inert and to hold the metal oxides are suitable at reaction conditions. Example of this are aluminum. Silicon, zirconium, Magnesium oxide and mixtures of two or more of these oxides.

The catalysts used in the process according to the invention can be prepared according to conventional processes be produced, for example by an impregnation process or a precipitation process. The catalyst can be in various forms, for example as pellets, tablets, spheroids, cylinders or rods.

The reaction temperature is in the range of up to 400 C. If the temperature is lower than 150 C. then the reaction rate is reduced, but if the temperature is more than 400 ° C, then undesirable carbonaceous substances arise, through which the catalylic effect is noticeable

is reduced. The preferred reaction temperature is in the range between 200 and 350 C. The reaction pressure is irrelevant, so that the reaction takes place at atmospheric pressure for a week. Pressures of less than 50 kg / cm ³ , preferably less than JO kg / cm, can be used in the method according to the invention.

The cifindungsgcmiiß used hydrogen oil fet is much smaller than with conventional methods, hole it varies depending on the reaction

conditions and the calorific value of the gas produced. In conventional hydrocracking processes it is necessary to Hydrogen in an excess of more than 4 hydrogen atoms per carbon atom in the Starting mixture / u reverberate to effect the reaction to expire. On the other hand, in the process according to the invention, the proportion of hydrogen can be reduced to one in the range between 3.5: 1 and 4.0: 1, preferably between 3.5: 1 and 3.7: 1. lying alom ratio the hydrogen atoms / u the carbon atoms in the starting mixture can be reduced. To this In a way, the hydrocracking reaction can with a low hydrogen concentration with a high conversion The starting hydrocarbons are carried out without increasing the formation of carbonaceous substances will. The unreacted hydrogen therefore does not need to be separated off in a further stage. This is one of the advantages of the invention.

The hydrogen used according to the invention can be pure hydrogen or a gas containing hydrogen. According to the invention, a mixture of hydrogen and methane is preferably used, since when methane is present, the proportion of ethane produced by the hydrocracking of hydrocarbons together with methane is greater than when only hydrogen is used alone. In the case of a gas mixture of hydrogen and methane, it is advantageous to use a gas which is produced by separating out carbon dioxide and a gas (a mixture of H _2, CH ₄ , CO and CO ₂ ) by steam forming a petroleum fraction. Such a gas generally contains more than 25 mol% methane and is well suited as a hydrogen carrier after separation of the carbon dioxide for the process according to the invention. Hydrogen can also be used as a mixture with nitrogen or another inert gas.

The fuel gas produced according to the invention contains methane and ethane as the main component and can be used as such or after mixing with a diluted gas or with other heating gases.

The invention is illustrated by the following exemplary embodiments described in more detail. All information in the design examples relate to percentages by weight, unless otherwise specified are

Example I.

30 ml of a cylindrical catalyst 3 mm in diameter and 3 mm in length, containing 17 parts of molybdenum dioxide. 14 parts of nickel oxide and 1 part of chromium oxide on KM) contains parts of an --aluminium oxide carrier, was placed in a reactor tube with a diameter of 2.54 cm given a mixture of η-butane and hydrogen was added to 50 mol% with a diluent gas mixed and through the Kalalysatorschicht under predetermined The results are given in Tabciic i

cm'

CJI

, (Mol wrhfllinis)

Room flow velocity

Table I.

2.0

4000 cm ³ / em ³ SuJ

Vcrsudisniimmcr Il Ul I. 305 305 Rcaklion temperature ('C) 295 N ₂ CH ₁ , Diluent gas N ₂ 81.8 81.5 Implementation of the nC ₄ H _{) 0} 70.3 Components of the generated Gas (mole percent) 20.7 25.8 H, 29.1 49.5 42.6 CH ₄ 36.5 9.59 9.88 C ₂ H ₁ , 7.81 13.5 15.2 14.0 6.07 6.Ii C ^J H ⁸ ₍₎ 9.90 5.16 4.31 CH ₄ : C ₂ H ₀ 4.68 (Molar ratio) 3.66 2.80 CH ₄ : C ₃ H ₈ 2.60 (Molar ratio)

In the case of using CH ₄ as the diluent, the CH ₄ : C ₂ H ₆ ratio and the CH ₄ : C ₃ H ₈ ratio in Table I were calculated without taking into account the CH _{4 used for the dilution.} The analysis results show the components of the gas generated after a reaction time of 3 hours. These results were essentially the same as those of the gas reached after a continuous reaction time of 24 hours.

Comparative example 1

The reaction was carried out in the same manner as in column JI of Example 1, with the exception that a nickel catalyst 6.3 mm in diameter and 6.3 mm in length and 25 weight percent Nickel was used in the form of Ni and NiO on a solid support. In this comparative example the molar ratio of hydrogen to n-butane changed according to table 2. The results are shown in Table 2.

Table 2

Trial number V Vl IV 3.0 6.0 H ₂ : C ₄ H ₁₀ (molar ratio) 2.0 80.7 78.5 l.'closure of the nC ₄ H | " 64.5

continuation Trial number V Vl IV Components of the generated 15.4 52.8 Gas (mole percent) 6.2 79.5 43.7 H ₂ 80.2 sense 0.1 Cn ₄ 0.7 0.4 0.3 1.2 4.8 3.1 C., H " 11.3 C ₄ H ₁ ,,

IO

Composition of I PCi (mol percentage)

n-Biilan 63.97

Iso-Biiian 32:59

l'iop.in 3.13

l'M.p \ len 0.10

Λ than 0.21

.1 lulle

Comparative example 2

The same reaction as in Example 2 was carried out. except that tungsten oxide was used instead of molybdenum oxide under the following reaction conditions. The results are compiled in Table 4.

table

Attempt Mimmcr
IX X

The gas produced after 3 hours and indicated in columns V and VI was used to determine the Gas components analyzed. The gas according to column IV. Which emerged after a reaction time of 5 minutes was. was then analyzed as a continuous response for more than 5 minutes was a noticeable one Reduction in the conversion of η-butane due to the formation of carbonaceous substances revealed.

B e 1 s ρ ic 1 2 _v

Hin liquid gas (hereinafter referred to as "LPG"), consisting of the following components, was preheated together with hydrogen to a temperature corresponding to the return temperature, and then through the same Kalalylische layer as in embodiment 1 under those in table 3 conditions shown. The results are shown in Table 3. The LPG used was analyzed by gas chromatography with the following results:

35

45 1.0

Reaction pressure (kg / cm ² )

Reaction temperature (C) 400

Room flow velocity- 2,000
age (cnrVcnrVStd.)

H ₂ : LPG (molar ratio) 3.6

Components of the generated
Gas (mole percent)

500
2,000

H ₂ 75.61 73.43 CH ₄ 0.22 0.55 C ₂ H ,, 0.11 0.21 C, H ₁ , 0.71 0.75 '-C ₄ H ₁₁ ) 7.94 7.82 HC ₄ H ₁₀ 15.42 15.24 Example 3

The catalyst of this embodiment was 3 mm long, had a diameter of 3 mm and contained 30 parts of molybdenum oxide. 5.0 parts of nickel oxide and 1 part of chromium oxide per 100 parts of a 7-Al11-miniumoxidträgcr. One from a gasoline fracture. whose characteristic values are given in Table · 5, uniJ hydrogen gas mixture consisting w. Ie to a corresponding temperature of the Reaklionstempcratur preheated and then hmdurchgclcitet according to Table 6 by a consisting of 60 cnr ¹ of the catalyst catalyst bed under the Rcaktionsbcdingungen. The results are shown in Table 6.

Yl'tstkll IUI 1.0 ΙΙ11Ι1ΚΊ MM 5.0 Table 5 C) .... 0.6817 VII 335 330 .. 35.5 C 2,000 2,000 Specific weight (15 4 3.0 2.0 Initial boiling point 51 8 C Reaction pressure (kg cm ² ! 89.2 92.5 ⁵⁰ Si im sau a Iy se 720 C Reaklionslcmpcratui I ("ι
Raiimslronuingsgesehwin- K) ⁰ / . , 1000 C digkcil (cm cm SId I
II, 1.1'Ci (MoI veil nisi 29.54 2.! 8 50% 125.2 C I niscl / ιιημ vnn n-Rtilan ("n) 52.06 75.28 90% 0.5 ml Best.iiullcilc des crzeuptcn 9.86 13.75 End-Sicdcpunkl 2.3 ml (i.iscs (Molprozcni)
II. 5.27 5.80 ⁵⁵ residue (II. 1.52 1.40 Dcslillation vcrlusl .... 1
( H 1.75 1.59 ι, 11. ^S 3 M7 Table 6
fiO VersiicliSMiiiiimcr <ι , 11 ¹ IH ^ (I I I 'Pd Xl XII ι Il II <Il Λ1 · .Ι \ γιΙι ihiiM 350 380 '' i. ι I '\ I U ί 10.0 20.0 Rciikiionstempcriitiii "(Cl 0.757 O.83S Rciiklioiisdriick (kg cnr) II, til im ¹ Il

ίο

continuation

H 'C (atomic ratio)
Room flow rate

^J dness of the liquid

^ (cnrVcnrVStd.)

"'Sales of the starting

'! materials

"Part of the generated
Gas (mole percent)

'■' H ₂

CH ₄
"C ₂ H ,,

C ₃ H ₈
• C _{4 +}

Liquid product (g)
CH ₄ / C ₂ H "(molar ratio)
Calorific value (kcal / Nm ³ )

Attempt number 3.75 Xl XII 2.0 3.60 2.0

95.0

7.61 72.16 13.59

6.64

4.1 5.31 1000

97.5

14.18

65.34

12.64

7.84

2.3 5.17 10 690

The above conversion of the starting material became the starting hydrocarbons per carbon atom and the proportion of the liquid product per 100 g of the starting hydrocarbons is determined.

Example 4

In the same way as in embodiment I, a heating gas was generated from n-Bulan, with the exception that the following five catalysts, each 3 mm in diameter and a length of 3 mm were used instead of the catalyst used in Ausführungsbeispicl 1. The achieved The results are shown in Table 7.

Composition of the catalysts catalyst A:

13.9 parts of molybdenum oxide and 8.1 parts of nickel oxide per 100 parts of an alumina support.

Catalyst B:

51.0 parts of molybdenum oxide and 12.0 parts of nickel oxide on 100 parts of alumina support.

Catalyst C:

68.0 parts of molybdenum oxide and 7.0 parts of nickel oxide per 100 parts of an aluminum oxide carrier.

Catalyst D:

14.1 parts of molybdenum oxide and 8.3 parts of cobalt oxide 100 parts of alumina support.

Catalyst E:

13.8 parts of molybdenum oxide and 8.0 parts of chromium oxide per 100 parts of an aluminum oxide carrier,

Table 7

Trial number XIV XV XVl XVII I 5 XVlIl XIX XX XXI XXIl XIII A. B. B. C. C. D. D. E. E. catalyst A. 305 295 305 295 305 330 350 370 390 Reaction temperature (O 295 86.5 79.4 88.1 80.2 88.6 73.4 81.9 74.8 82.1 Implementation of the n-C4.H | ₀ (%) 78.1 Components of the generated Gas (mole percentage) 12.8 26.9 17.0 28.0 18.5 17.5 10.7 15.6 8.86 H ₂ 21.4 62.6 42.3 54.8 40.2 52.4 58.4 67.0 60.7 69.4 CH ₄ 50.7 7.44 8.80 10.2 8.88 10.3 6.21 6.70 6.98 7.30 C ₂ H ₆ 8.09 12.6 15.2 14.0 16.3 15.0 8.99 9.57 8.32 8.46 C ₁ H ₈ 12.4 4.50 6.90 4.00 6.60 3.80 8.86 6.03 8.39 5.96 C ₄ H ₁₀ 7.30 Bc i s ρ i e

In the same manner as in the embodiment, which was obtained by removing the carbon dioxide from

Game I, a heating gas made of n-Bulan was used among the

Table 8 produced the conditions with which gas produced by fto substances had been produced. The

Exception that the hydrogen-halligcs gas used contained hydrogen-containing gas:

Mol per cm

H ₂ 26.2

CO 1.26

CO ₂ 2.94

CH ₄ 69.6

tr

11 12

Table 8

Attempt number 1.7 XXIV 2.0 XXIII 300 320 H ₂ / nC ₄ H, ₀ (molar ratio) 2000 2 (KX) Reaction temperature C C) 72.4 80.1 Room flow velocity
füpkpif tem / cm / StH ) I ^ J Iknvl L- | VsJ 1 J IvMiI / fcj LvJ * /
Implementation of the nC ₄ H, ₀ (%) Components of the generated 2.0 2.1 Gas (mole percent) 0.5 0.4 H ₂ 1.4 1.9 CO 83.0 84.6 CO ₂ 3.8 3.5 CH ₄ 5.4 4.9 C ₂ H ₆ 4.0 2.5 C3H8 11 220 10 720 C ₄ H ₁₀ Calorific value ikcal / Nm ³ )

Claims (2)

Patent claims: I. Process for the production of as llauplbcstandleiic Methane and Allian contain ciulem '■ Heating gas with a calorific value of at least' 9500 kcal / Nnr ¹ , with which as the starting mixture / a hydrocarbon with at least 3 carbon atoms and a boiling point not higher than 150 C with hydrogen in the gaseous Phase brought together in the presence of a catalyst at a temperature between 150 and 400 C. is characterized by that the catalyst is supported on a solid support molybdenum oxide in an amount of 10 to 70 percent by weight and at least one of the following oxides, namely nickel oxide, cobalt oxide, Chromium oxide in a proportion of 3 to 15 percent by weight, based on the Triiger weight, contains and that the atomic ratio of hydrogen to carbon in the starting mixture is between 3.5: 1 and 4: 1. 2. The method according to claim 1, characterized in that that the hydrocarbon consists of at least one of the following hydrocarbons. namely saturated aliphatic hydrocarbons, saturated alicyclic hydrocarbons and aromatic hydrocarbons.