DE1470705A1 - Process for the production of methane-containing gases - Google Patents

Description

Patent application

The Gas Council, 1, Grosvenor Place, London / Great Britain

concerning

Process for the production of methane-containing gases

The invention relates to a method for the production of metharijialtigen Gases, - ^ ie increasing use of natural gas in countries with a significant manufacturing industry common gases for industrial and domestic use It has more combustion properties than natural gas 1-roülem of coordination on. At present, natural gas can double , '/ can also be used to enrich a low-value gas, e.g. a gas which, according to the Lurgi-Veri'aiiron Was manufactured, and for the formation to ge • // 'j / iiixicriem Town gas. It is possible that the calorific value of btultgas will be increased in the future, so that natural gas will be available directly in the Supply system can be used. To a gas with the same quality to produce different types of gas

U 9 Ii Ί 3/1 U 1 U

have sources available, e.g. industrially produced gas; that has practically the same properties as natural gas having.

The main differences between an industrially manufactured one 'Jas, ζ.Β »the current town gas, and natural gas are as follows i

1 · The calorific value of natural gas is usually much greater than that of industrially produced gas;

2. The flame speed of natural gas is lower than that of industrially produced gas.

The greater calorific value of natural gas is due to its high genalt of methane and other hydrocarbons, while the lower flame speed is due to being practical no hydrogen is present.

A process aimed at producing a gas that is exchangeable with natural gas must involve overall chemical reactions work, according to which gaseous hydrocarbons, but ice an appreciable amount of hydrogen.

_öAD

909313/1018

³ H70705

Low boiling hydrocarbons, which are predominantly paraffinic hydrocarbons, a.B. those with 4 to 15 carbon atoms contained per molecule, can be gasified or reformed by reaction with steam to a gaseous end product, which contains methane, carbon monoxide or dioxide and hydrogen. Such a method is described in British patent specification 820,257. The methane content of the gas can be increased by influencing the methane formation reaction. However, the resulting gas contains large amounts of carbon dioxide, which must be removed if a gas with the combustion properties of natural gas is obtained v / i 11. One can use coke oven gas, z.E. Convert coke oven gas to increase the methane content} mainly contains the gas produced during this process Methane and hydrogen, and you have to remove the hydrogen if you have a gas with the combustion properties of natural gas wants to receive. The invention is directed to a method for producing a gas having the combustion properties of natural gas directed, in which the difficulties outlined above are overcome.

The invention relates to a process for the production of methane-containing Gas, which is characterized in that a gas, the methane, carbon monoxide or carbon dioxide and hydrogen is

ORIGINAL 9ÜHÖ13 / 1018

holds, and that after the methanation reaction methane and carbon dioxide would contain, mixed with a second gas, daa methane, carbon monoxide or carbon dioxide and excess hydrogen contains, and that would contain predominantly methane and hydrogen after the methanation reaction, the mixture of methanized two gases, so that carbon monoxide or carbon dioxide and hydrogen are converted to methane and water vapor, the The ratio of the two gases present in the mixture is chosen so that the resulting gas after the methanation reaction contains practically no carbon monoxide or dioxide or hydrogen,

The reaction between the hydrogen and the oxides of carbon methane and water vapor is known, and no patent protection is sought for the reaction as such.

The first gas is preferably a gas with a methane content of at least 50 vol .-? 6 based on the volume of methane, hydrogen and carbon monoxide or dioxide; it is obtained by adding a predominantly paraffinic, vaporous hydrocarbon Reacts with steam over a catalyst | the predominantly paraffinic, vaporous hydrocarbon preferably has 4 to 15 carbon atoms per molecule. The second Gas is preferably coke oven gas, but it can also be produced by gasifying light distillate and crude and heavy oil.

09813/1010

be the gas.

The invention also relates to an improvement or modification of what is set out in claims 1 to 5 of the British patent specification 820 257 claimed process, such that the methane-containing gases obtained there over a methanation catalyst can be further reacted with a hydrogenation gas, hydrogen and the oxides of carbon being converted to methane and wherein the proportion of the hydrogenation gas is chosen so that the resulting gas is practically after the methanation no more carbon monoxide, carbon dioxide or hydrogen contains.

Further improvements or variants of the method according to this patent are in a number of patent applications (Brit. Note 21 004/61, 22 488/61, 36 079/62 corresp. G 38 740 IVd / 26a, 40 472/62 corresponding to G 39 016 IVd / 26 a, 13 076/63 according to G 40 243 IVd / 26a and 4 958/64) and can be used for the method according to the invention.

In the reaction between the first gas, i.e. the methane-rich gas, and the second gas, i.e. the hydrogen

909813/1010

methane and water are obtained by reacting the hydrogen with the oxides of carbon that are contained in both gases. If the reaction temperature and the proportions of the two gases used for the reaction are suitable
selects, the gas produced as the end product contains almost exclusively methane and a very small amount, preferably
less than 10 vol. 5'ό, carbon dioxide, carbon monoxide and hydrogen in addition to inert gas which was present in the hydrogen-containing gas.

The reaction is preferably carried out under pressure in order to facilitate the formation of "" ethane.

The operating pressure can be up to 100 atmospheres, preferably about 10 to 10 atmospheres.

The invention will be illustrated by way of an example of a specific one
Embodiment described, reference being made to the accompanying schematic representation.

The hydrogen-rich gas y, for example coke oven gas, although other gases containing more than 40 ° / o of hydrogen and less than ■ Λ0 5 »nitrogen can be used, in a known manner up to a Hest of 0.0001 ^c / o (1 ppm.) (as HpS) of

ORIGINAL BATHROOM 909813/1010

Sulfur compounds freed. This can e.g. D. by cooling, but preferably by hydrogen desulfurization over.eine molybdenum-containing catalyst happen at about 35O ° G, whereupon the hydrogen sulphide is absorbed at the same temperature by a metal oxide, e.g. iron or zinc oxide. the Purification is preferably carried out at positive pressure in order to hydrogenate the sulfur compounds and the unsaturated hydrocarbons to facilitate; the overpressure in the cleaning device 10 is, for example, 25 atmospheres.

The purified, hydrogen-rich gas from which 11 of all Water vapor has condensed, is mixed with a petroleum distillate 1, in amounts of about 31 - 62 liters (0.5 1.0 cu.ft / lb.) hydrogenation gas hydrogen per kg of distillate, and the mixture 2 is preheated to 35O ° C before it is over a nickel- and molybdenum-containing hydrogen desulfurization catalyst is passed; then the mixture is over a metal oxide, E.g. over iron oxide or zinc oxide, in order to remove the hydrogen sulfide at 3. Sometimes you have to have more than one Carry out treatment to achieve the necessary degree of purity,

Process steam 4, which may be superheated if necessary, is mixed with the purified petroleum distillate steam in a ratio of 1.6-2.0 parts by weight of steam per weight

909813/10 1 β

" ⁸ " U70705

Partly distillate and preheated at 5 to 450 - 600 ° 0. The mixture is over a nickel-alumina catalyst, as it is in d «n British Patent Applications 21004/61 (British Patent Specification 969 637) and 22488/61, which Catalyst temperature does not exceed 50 ° C. The distillate is quantitatively converted into a methane-rich gas 6, with the undecomposed water vapor is condensed and removed at 8, and the drying gas 7 for mixing with the purified coke oven gas 10 is forwarded.

The methane-containing gas 7 is mixed with the purified coke oven gas 10 and the mixture 12 is at a temperature of 200 - 500 ⁰ C passed over a methanation catalyst, a temperature of 250 - has bOO ° C. The hydrogen and the carbon oxides contained in the mixture 12 are converted via the methanation catalyst and provide methane and water. After the reaction there are still small amounts of carbon dioxide, carbon monoxide and hydrogen, but the carbon dioxide content is so small that it does not need to be removed by a further absorption process. Ethane, which may be present in the coke oven gas after cleaning, is almost completely decomposed to methane and hydrogen under the conditions of the methanation reaction. The water formed is condensed and drained at 14, and one obtains a

ORIGINAL BATHROOM 909813/1010

gaseous end product 15 »which consists almost entirely of hydrocarbons and inert gas. The height. Proportion of hydrocarbons and the practical absence of hydrogen give your gaseous end product the properties of certain Natural gases.

The methanation reaction proceeds among those described here Conditions are exothermic and one must remove heat from the system in order to keep the catalyst at the prescribed temperature to keep. This can be done in a number of ways, such as:

1. by recycling a portion of the gaseous end product through the catalyst vessel, the gas is cooled in a heat exchanger before it is mixed with the incoming reaction gas;

2. By installing suitable cooling coils in the catalyst vessel, through which a liquid is duroheaded so that the heat is transferred from the catalyst to the liquid or the apparatus.

In the table below, as examples, more detailed information on the reactants and the reaction conditions for

BAD ORIGINAL 9 0 9 ii 1 3/1 0 1 8

H70705

Formation of each gas made its combustion properties enable an exchange with natural gas. The numbers of the gas flows in the table correspond to those in the figure.

According to the present example, a petroleum distillate having a density of 0.71 at 20 ⁰ G, a Sndsiedepunkt of 165 ⁰ C, a carbon content of 65.1 üew.- ° / o and a hydrogen content of 14.9 wt was a hydrocarbon oil ? » used. The purified coke oven gas contained $ 0.00008 (0.8 ppm.) Sulfur. The composition of the gases emerging from the catalytic gasifier and the methanation system 13 corresponded to the equilibrium for the two heatings under the operating conditions.

(1) CO + 3H ₂ CH ₄ + H ₂ O

and (2) CO + H ₂ O CO ₂ + H ₂

The method according to the invention is characterized, inter alia , in that in both catalytic processes the equilibrium is reached with good approximation; one can therefore change the composition of the gas by changing the operating temperatures in the catalyst bed. An advantage of this execution

9098 13/1010

Debeispieles is that after completion of the implementation a separation of carbon dioxide or carbon monoxide is not necessary.

In the figure is another embodiment for the method specified; Via the line 16 a branched off part of the purified, hydrogen-free gas is evaporated with the gas and purified distillate / water vapor mixture entering the catalytic gasifier 5, mixed. Take the share of hydrogen-rich gas, so the in the catalytic gasifier the overall reaction taking place is more exothermic and the heat must be removed from the catalyst bed to reach the catalyst temperature keep constant. The heat can be removed from the catalyst in the same manner as in the above methanation catalyst described. At the same time, the reaction that takes place in the methanation stage is less pronounced exothermic, and it takes less heat to remove from the catalyst. You can also all of the hydrogenation gas through the direct the catalytic carburetor, and in this case it may be advantageous to use the hydrogen-rich gas before or during the To mix cleaning with the distillate, since then you do not need your own cleaning system for the hydrogenation gas.

909813/1018

Table I.

Gas stream no. | 1 0.0302
(1,682) 2 3 4th 5 6th -2 14.20
1.05
10.45
^ 6.55
37.75 7th distillate
g / kcal (lbs./tuerm) end gas 0.0302
(1,682) 0.0302
(1,682) 0.0302
(1,682) hydrogen rich gas
g / kcal (lbs./therm) Endgai ), 081x10 " ²
(0.045) 0.081xi0 ~ ²
(0.045) 0.081x10
(0.045) 3560
(400.4) co
CD
x
GC Gas composition
(Vol-jb). CO ₂
§8th
H ₂
GH ₄
(uns.) G ₂ E ₆
H ₂ O 540 22.80
1.70
16.80
58.70 i ■ Steam and con
densat kg (lbs.) 11250
kcal / kg
(Btu / lb.
20250) 1.267
(2,792) 1.267
(2,792) 9250
(o, 367) calorific value
kcal / m ^ (3tu / cu.ft.) 25th 0.0014
(4,519) 5720
(643.2) Temperature ⁰ C 8600
(0.341) 350 330 230 520 19.40 25th Potential warmth
kcal (therms) 0.0302
1,682) 8800
0.349) 8800
(0.349) 6800
(0.349) 9250
(0.367) Mass flow
g / kcal (therms) end gas ( 102.0 0.0311
(1,727) 0.0311
(1,727) 0.0501
(2,792) 0.0814
(•• r, 519) 0.0529
(2,937) Molecular weight 83.76 33.76 18, 02 25.74 19.96

Grass Troia No. 8th gas Taoelle I (cont.) 9 10 11 12th • 13th 14th ■ I.
I.
1
it distillate
g / kcal (lbs./thierm)
Engine hydrogen-rich gas
g / kcal (lbs./therm) Em 0.719
(1,382) 0.0764
(4,246) 0.0755
(4,200) 0.081x10 "*
(0.045) Grass composition
(Vol.-Jt) CO2
O ₂
CO
Hp
C & 4
(uns. +) C ₂ H6
N ₂
H ₂ O 2.35
0.50
6.15
55.20
25.55
+2.55
8.00 2.45
6.35
53.45
26.25
2.30
8.20
1.00 2.45
6.40
54.05
2b, 50
2.30
8.30 8.15
5, U5
4 ^, 15
35.35
1.65
5.90
0.75 2.55
0.05
2.55
63.75
0.25
7.60
23.25 3.3 (
0.0!
>, 3 (
83.1!
0.3 <
9, "9 < cc
C.
cc
'OC Water vapor and con
densat kg (lbs.) 25th 0.766
(1,690) ti calorific value
jccal / m * (3tu / cu.ft.) 4525
(435.5) 4390
(492.2) 4420
(496.8) 4750
(5: 4.4) 5770
(647.6) 7p20
(845.0 Temperature ⁰ C 0.0285
(1,582) 25th 350 25th 260 40Ü 25th 25th Potential warmth
kcal (therms) 18.02 18200
(0.723) 17780
(0.705) 202
(0.008) 27000
(1,072) 25200
(1,000) 25200
(1,000 üassenstrom
g / kcal (therms) end gas 0.0764
(4,246) 0.0755
(4,200) 0.081x10 ~ ²
(0.045) 0.1285
(7,137) ü, 1205
(7,137) 0.0 yjA
(1,690) 0.0979
(5.447 Molecular weight 10.98 11.30 11.21 13.81 17.78 18.02 17.70

■ ^U "U70705

Assuming there; 3 the Y / arms recovered and used to generate of steam and to preheat the distillate, hydrogen-rich gas and boiler feed water is the quotient of:

potential V / poor in the gas

: = 92 # (more potential Approaching heat in the starting materials

The energy costs are not taken into account here.

Claims

909813/1018

Claims (7)

Claims Vi J Process for the production of inet hanhaltigen gases, thereby characterized in that one has a first gas, dao methane, carbon monoxide or contains carbon dioxide and hydrogen, and which would contain Lie than and carbon dioxide after methanation, with a second gas, the ethane, carbon monoxide, or carbon dioxide and excess hydrogen, and after i, .ethani they contain predominantly methane and hydrogen would, mixed, and the mixture of the two gases for the purpose of conversion methanated from carbon monoxide or carbon dioxide and from / hydrogen to methane and water vapor, with the ratio of the two gases in the mixture is chosen so that the resulting Gas after methanation contains practically no carbon monoxide or carbon dioxide and no more hydrogen. 2. The method according to claim 1, characterized in that a gas with at least 50 Vol- ^ b methane is used as the first gas . 3. The method according to claim 1 and 2, characterized in that as the first gas, by converting a predominantly paraffinic one Hydrocarbon with 4-15 carbon atoms per iiOiekul with excess water vapor over a nickel ca- BATH 90981 3/1018 ' U70705 talysator obtained G-as is used. 4. The method according to claim 1-3 »characterized in that coke oven gas is used as the second gas. 5. The method according to claim 4, characterized in that one the implementation for prints up to 100 at. 6. The method according to claim 1-5, characterized in that one works at pressures of 10 to 50 at. 7. The method according to claim 1-6, characterized in that the ratio between the two gases in the mixture as selects that the gas obtained in the methanation has less than 10 vol- # carbon monoxide or carbon dioxide and hydrogen contains. 909813/1018