SU50160A1 - Method for producing carbon monoxide-poor or free mixtures of hydrogen with oxygen - Google Patents

Description

-.rns -Magneslt Aktlengeseusebatt, in g - brrrr action of the patent spreads ExC Water is decomposed by burning carbon (water gas) according to the reaction 2C + - 2CO + 2Ng - 57.2 cal. CO also produces COZ according to the equation: C + 2H, 0 CO, + 2H2-18.0 cal. Between CO and CO, equilibrium is established depending on the temperature of the atomic temperature ;; .-% Gore: nGso TaH To-az EGr: as in ° C dG ° to WJ theoretically to the gas mixture and Co% p; b; shallowly less than x ° 5L; It is less profitable to spend less, then it would be advantageous to carry out the process of obtaining water from this equation. It was also suitable for the technical production of hydrogen to obtain a gas mixture obtained at a low temperature, because it is technically much easier to separate carbon dioxide than to remove carbon monoxide. However, this is hindered by the fact that HeSbiBHO reduces the rate of reaction that decreases with the measure of decrease in temperature at those temperatures at which equilibrium is established in favor of LRG. P, irpi-r: 15 years old On August 31, 1936, the avneni of I. is far from sufficient for GpTezhne in% G dyagalam G., e. VOY mixture. Liquefaction, servant,.-Og.

carbon to carbon dioxide using water vapor and through catalysts. This method is economical if the oxidation of carbon monoxide is carried out under elevated pressure, but in its really valuable forms of execution it is not simple and at the same time gives a mixture of hydrogen and carbon dioxide, and this mixture always contains carbon monoxide, even in small quantities, so that In order to obtain pure hydrogen, additional chemical purification is necessary (for example, washing the gas under high pressure with a solution of copper oxide).

Another method for producing pure hydrogen from water gas containing carbon monoxide is used to accelerate the reaction by binding carbon dioxide to substances that absorb this latter, in particular, lime; by the continuous extraction of carbon dioxide from the reaction mixture, the equilibrium associated with the reaction of CO —H 2 O; By -f-CO2, is shifted towards carbon dioxide. To carry out this method, water gas is passed along with an excess of water vapor through lime, which is heated in the retort to a temperature that is lower than the decomposition temperature of calcium carbonate. The addition of catalytically active substances, as it turned out, accelerates the reaction. Preferably lumps of lime are used, which, when water is passed through it, are quickly converted to carbon dioxide. From this latter, calcined lime is recovered by burning, again brought into contact with water gas. Further improvements were then made to improve this method. In particular, it was proposed to supply water vapor in an exact or exact stoichiometric ratio, which corresponds to the reaction equation

CO-f- NgO .-. Ns + COg, and replace with magnesium oxide specially prepared catalysts (metal oxide or metal), which were previously used for this process. In accordance with the essence of this process, the operating temperature must be below the decomposition temperature of calcium carbonate so that carbon dioxide, at its moment of occurrence to be removed from the gas phase by chemical bonding, is not split off again during the process. But it was assumed that it would be possible to work below this limit at arbitrarily high temperatures.

The present invention primarily solves the problem of directly producing carbon monoxide-poor or mixtures of hydrogen and carbon dioxide free from it by means of a water gas formation process, in the presence of impurities accelerating the reaction, according to equation II. According to the invention, a non-bespoke catalytic formation of carbon monoxide-poor or mixtures of hydrogen and carbon dioxide free from it is a mixture of oxide or hydrate of magnesium oxide or magnesium carbonate with coal at an operating temperature that exceeds the decomposition temperature of magnesium carbonate, but not higher than 750

The invention proceeds from the established fact that for the formation of carbon monoxide-free water gas, the equilibrium states associated with the + C02 reaction are crucial.

From this point of view, the most favorable reaction temperature is 500 °, because with it the equilibrium is quantitatively shifted towards carbon dioxide. Above 500 ° C, in the presence of C, as the temperature rises, it grows to an increasing degree again into CO, so that the formation of a temperature range of more than 750 ° for carbon monoxide-poor gas mixtures is no longer suitable. Below 700 - 750, the reaction rate during the formation of a water gas is already so reduced that the reaction becomes technically unfeasible. Consequently, it was necessary to find an effective contact mass, which would sufficiently accelerate the reaction of the formation of water gas in the temperature range below 750. A mixture of coal and magnesium carbonate turned out to be more suitable for this purpose. This is explained by the relatively low temperature of decomposition of magnesium carbonate, which can be lowered below 500, diluting the gas phase with water vapor, i.e., lowering the vapor pressure of carbon dioxide. At 500 reaction

MgCOs: MgO + C02

is at approximately 50% equilibrium, if quantities of water vapor are used, corresponding to the stoichiometric ratio of Equation II or slightly superior to this ratio. This compound, therefore, has the property of quickly perceiving and releasing carbon dioxide under the conditions of the process of producing steam according to the equation I at a temperature that best prevents the formation of carbon monoxide. This is unattainable neither with the help of alkali carbonates, nor with the help of carbonate lime. If one conducts the process of producing water gas using magnesium carbonate as a catalyst at temperatures slightly above 500, then according to the invention it is possible to directly obtain water gas practically free of carbon monoxide.

If, for example, you mix charcoal with magnesium carbonate in a ratio of 100 weight parts of coal to 5-25 weight parts of magnesium carbonate and process this mixture at 500 ° (approximately) with stoichiometric amounts of water vapor (respectively, 2 mol of H2O to 1 mol of ), the reaction practically proceeds by equation 11 at an absolutely sufficient rate. This method is also important for the production of water gas itself. Carbon dioxide, as is well known, is easily removed from this mixture, and therefore it results in, first of all, quite technically suitable method of obtaining pure hydrogen through the process formed by 1 water gas.

Instead of magnesium carbonate, it is, of course, also possible to introduce magnesium oxide or magnesium oxide hydrate into the reaction, which is immediately converted to magnesium carbonate. Further, this method can also be carried out using natural starting materials containing magnesium oxide or magnesium carbonate in sufficient quantities. The catalyst is left without regeneration in unchanged composition, retaining its activity, so that only gasified coal is added. Since the course of the reaction according to the equation And the formation of water vapor is weakly endothermic, the reaction temperature can be maintained at about 500 by heating with very moderate heat input. Instead of directly gasifying coal with steam in this way, obtaining a mixture of hydrogen and carbon dioxide free of carbon monoxide, it is also possible to use this method to completely liberate water mixtures containing carbon monoxide or similar gas mixtures from impurities. carbon monoxide. For this purpose, the carbon monoxide-containing gas or the gas mixture containing it, together with water vapor, is also passed through a mixture of coal (or carbon-containing substances) with magnesium carbonate, maintained at a temperature above the decomposition temperature of magnesium carbonate, but slightly higher than 500 °. The course of the reactions can be represented as follows:

2CO С + С02 С-Ь2Н20 СО2 + 2Н2

2CO + 2H2O 2CO2 + 2H2

Since the 2CO C + CO2 reaction is sharply exothermic, in this case a very moderate external heat supply is required to maintain the reaction temperature at about 500. If you add just as much steam as is necessary for the carbon formed by the equation 2CO to convert to water. as if steam is in statu nascendi to carbon dioxide by the equation II of formation of aqueous gas, then in this form of the method the catalytic mass is fully preserved; the method can be carried out without adding any char. In all cases, B, the reactivation of the catalytic mass does not arise under any circumstances, since in this case the working temperature is lower than the decomposition temperature of magnesium carbonate.

Before the gases leave the installation, it is enough to bring them for 20-30 seconds into contact with a layer of contact mass, the temperature of which is maintained at a level not too higher than 500. Under such a premise, those zones of contact mass through which gases pass earlier can heat also to accelerate the reaction to temperatures lying in the range of 500-750 °.

Example 1. By thoroughly mixing the charcoal with caustically burned magnesite, so that the mixture contains, for example, for every 4 weight parts of coal, 1 weight part of magnesite, allows this mixture to descend into the heated outside of the shaft furnace, in which the contact mass is heated to about 500 °. The contact mass exiting from the lower end of the shaft is poor in coal, again mixed with coal, and in the circuit is reloaded from above into the shaft furnace. According to this method, it is possible to process about 30-40% of the substance containing coal in an hour per hour. Instead of a shaft furnace, a rotating furnace is likewise applicable.

If one of the usual methods of removing carbon dioxide from water obtained from this method, free of carbon monoxide, water gas, for example, washing it with water under pressure, then this very simple method will give completely pure hydrogen directly, i.e. without additional chemical cleaning.

Example 2. Thoroughly mixing finely ground caustically burned magnesite with charcoal in a ratio of 1: 4 to 1: 5 transforms this mass into a granular form with the addition of some binding agent, for example, an alkali carbonate solution. Contact mass should be placed in heated outside pipe. The gas mixture to be purified is passed through a heated contact mass with the addition of stoichiometric amounts of water vapor in relation to HgOiCO.

Under these conditions, the same amount of contact mass is expended.

any amounts of carbon monoxide containing gas mixtures can be recycled to carbon dioxide, and the amount of contact mass expended does not increase or decrease if water vapor is used in an amount corresponding to the content of carbon monoxide.

The subject matter of the invention.

1. A method for producing carbon monoxide-poor or free mixtures of hydrogen with oxygen by exposing water to coal or coal-containing substances in the presence of a catalyst at temperatures below 750 °, characterized in that water is decomposed by a mixture of magnesium oxide or the operating temperature is 8 magnesia compounds of the latter, and the coal is produced at a temperature above the decomposition temperature of magnesium carbonate.

2. Accepting the method indicated in claim 1 using an amount of water vapor corresponding to approximately the stoichiometric ratio: 2 moles of water per 1 mole of carbon, characterized in that the operating temperature is maintained at about 500 °.

3. Change of the method indicated in paragraphs. 1 and 2, when used to release it from carbon monoxide, water or similar gas, by oxidizing carbon monoxide with water vapor in the presence of magnesium oxide or magnesium compounds passing to the latter, characterized in that the gas mixture containing carbon monoxide is passed through with water. steam above a mixture of magnesium compounds with coal or substances containing coal, maintained at a temperature higher than the decomposition temperature of magnesium carbonate, but not exceeding significantly 500 °.