DE659407C - Process for the production of grainy cleaning compounds for the removal of sulfur compounds from gases - Google Patents

Description

Process for preparing granular cleaning compositions for removal of sulfur compounds from gases When carrying out catalytic gas reactions it is necessary to remove the synthesis gases from contact poisons, especially from sulfur compounds free of both inorganic and organic nature. For sulfur cleaning of the gases, cleaning compounds were used, which essentially consisted of the oxides or hydroxides of iron. It is known to use spherical cleaning compounds apply that out. Iron oxides, a binder, 'such as. B. cement, and one extremely small amount of a heat decomposable salt such as B. ammonium carbonate, exist as a loosening agent. The production of the * balls takes place in the way, that the mixture of the aforementioned substances with a suitable water content to form moldings pressed or broken up into small particles by means of mechanical devices, which you can then roll over rotating disks until they get the desired have assumed a spherical shape. During or after the shaping, the spherical The structure is heated to increase the porosity and strength of the balls as a result of the leakage of water to increase, the added small amounts of decomposable salts, such as. B. ammonium carbonate, the loosening of the cleaning compound favor. Furthermore has it has already been proposed for the production of gas cleaning compositions with a large surface and strength reactive masses containing iron oxides with binders, such as cement, magnesia cement, lime or gypsum, in the presence of smaller amounts, about 1 / Y% more Mix amounts of alkali or ammonium bicarbonate and a little water intimately and to deform the mass before or after brief heating to q.o to 5o °. This Brief and gentle heating is only used to decompose the bicarbonates, whereby fine pores are formed in the mass.

It is also known that the removal of the last portions of sulfur compounds from gases particularly expediently takes place with a mass that consists of an intimate mixture of the oxides and / or hydroxides of iron with greater than 5 percent by weight amounts of solid alkali carbonates. So far, this fine cleaning compound Manufactured in such a way that the mixture is mixed with water to form a stiff pulp baked into a solid mass by heating and this was then comminuted.

We have found that when the mixture is completely, i. H. until dried for practical freedom from water. and the received Dimensions then granulated by crushing ,, die'-finished dried mass as proves so little firm that the grain has a lot of abrasion in the form of a fine dust arises, which cannot easily be reprocessed into solid grain. It was also not possible to place the fine cleaning agent in known mixing devices constant heating and stirring of the mixture to produce the finished grain. To this One only obtains masses that are granulated in the shape of a bulb and are rock-hard and have completely lost their porosity.

The ailments outlined above can be avoided by that according to the invention, the mixture of Al-potassium carbonate and moist lux mass This mixture is initially converted into a pulpy or dripping liquid state then by heating and possibly simultaneous stirring only up to medium water content dries and the mass solidified by cooling divided in this state for the purpose of shaping. For this purpose, the starting components intimately mixed and heated until the entire mixture is mushy to dripping liquid is. It was also found that this liquefied mixture on cooling to a extraordinarily hard and brittle mass solidifies, its hardness and brittleness with increasing water content rises sharply. These hardened masses that still contain water can be perfectly grained without causing a lot of abrasion.

In addition, this can solidify the cleaning compound be achieved that the liquefied mixture with heating and simultaneous Agitation is predried. Because the crumbling mass particles are constantly come into contact again with the still pulpy mass, those in the material pores initially created by the leakage of water are repeatedly clogged, as a result of which solidification of the grain occurs.

The porosity of the completely dried cleaning compound depends on the Final water content before the final drying, in such a way that the finished mass the less water is expelled while stirring, the more porous it becomes has been drained. With the water content at rest at the beginning of drying (finished drying) the later porosity is given.

By heating and stirring the ingredients in the presence of suitable ones Amount of water initially creates a thin paste. This can be done by further heating solidify to a greater or lesser extent while stirring at the same time, while the then any remaining water can be expelled at rest.

So you have it by measuring the solidification or final drying periods in the hand to arbitrarily determine the properties of the end product.

The preparation according to the invention of the cleaning compositions should be based on the following Example will be explained in more detail.

In one with an agitator. provided mixing device; oo kg of lux mass with a moisture content of 45 0'o and 18 ounces of calcined soda intimately mixed. A strong self-heating occurs as a result of the water absorption of the soda of the mass, so that with little additional heating after a mixing time of Complete liquefaction of the mixture has occurred within 10 minutes. The so obtained liquid mixture is under further external heat supply and vigorous Stir predried, the mixture gradually escaping with the escape of steam becomes more viscous. This three-hour pre-drying is followed by a two-hour Further drying, during which the agitator is switched off, for further solidification to avoid the masses obtainable from the mixture. The further division of the The mass removed from the mixing device can be placed on either cold or warm Ways take place. In the former case, that obtained in the above manner is obtained pasty mass tarred on sheet pans and at smoking temperature, d. H. on about Cooled 2o °, whereby the mixture hardens. The mass solidified in this way is then crushed in a fine crusher and the undersized grains removed by sieving. The grained Masses have a moisture content of about 23% and are subsequently by drying with sufficient quantities of hot air to a water content brought down by less than 5%. This measure is necessary in order for it to be used the grains as a cleaning compound for the removal of sulfur from gases at elevated levels Temperatures cannot soften the cleaning compounds. The dried one The grain had a pore volume of 430/0 and a bulk density of 0.50. The at the grain accumulating dust was about 20% of the finished grain and is always the next batch added so that the starting material is completely processed to finished grain can be. The excellent suitability of the fine cleaning compounds produced according to the process it follows that this mass contains 15 to 20% of its weight in sulfur. to record can without it the end of the sulfur uptake is reached.

The further division of the pre-dried, emptied from the mixing device, still water-containing mixture can also be done in such a way that the still warm and dividing plastic mass by extrusion or the like. In this case, the final drying of the strands follows immediately. By mild After the finished dried strands have been comminuted, a cleaning compound is more useful Grain size obtained without the occurrence of significant dust fractions.

Claims (2)

PATENT CLAIMS: i. Process for the production of granular cleaning compounds for the removal of sulfur compounds from gases using a mixture of more than 5% alkali carbonates with oxides and / or hydroxides of iron, thereby characterized in that the ingredients first at a moderately elevated temperature and in Presence of water to a pulpy to dropwise liquid mixture intimately stirred and then this mixture by heating with or without simultaneous stirring is incompletely dehydrated, whereupon the mixture either after cooling to about 20 ° crushed in a fine crusher or divided by extruding while still hot and finish drying with hot air and in the case of using extrusion presses the dried strands are re-shredded. 2. The method according to claim i, characterized in that the water from the pulpy to drip liquid Mixture driven off incompletely by heating first with and then without stirring will.