DE2651177A1 - PROCESS FOR REMOVING SULFUR COMPOUNDS, IN PARTICULAR H DEEP 2 S, FROM A SYNTHESIS GAS - Google Patents

Description

Saarbergwerke AG P 76/17? RR1 177

Saarbrücken, November 4, 1976 3 Ma / Pe

Process for removing sulfur compounds, in particular H ₂ S, from a synthesis gas

The invention relates to a method for removing sulfur compounds, in particular H ~ S, from a synthesis gas, which by gasification of coal or other carbonaceous Solids in a gasification reactor at elevated temperature are created by mass transfer with mineral-like substances Absorbents.

Synthesis gas produced by gasifying coal with water vapor and oxygen or air usually contains sulfur components, the corrosion damage in the system parts of the consumer during or after the gas has been used in a consumer cause or lead to environmental pollution if the exhaust gas is discharged into the open atmosphere without being cleaned.

From DT-OS 1444961 a method for desulfurization of raw gases originating from fuel gasifiers is known. Here entstandenem in a separate gasification chamber, about 1000 ⁰ C hot raw gas in a downstream Reaktionaraum lime is added as an absorbent, which is reacted with the Schwofolverbindunqfui dea raw gas and deposited again in a downstream cyclone.

The disadvantage is that a great technical effort is required in this known process and that the degree of desulfurization is not particularly high. There are a beoondercr Vorqnuunqs- and reaction space required to carry out the desulfurization

809820/01 3S

Saarberg *: / erke AG

As the mass transfer takes place in one of the reactor downstream process stage takes place in suspension, is also available for desulfurization standing surface small and thus the degree of desulphurisation small amount.

The object of the invention is to develop a method by means of which the highest possible sulfur content from the generated in a reliable manner with little technical effort Synthesis gas can be separated.

This object is achieved according to the invention in that the Substance exchange with the absorbent predominantly in the liquid phase takes place.

There is an important advantage of the method according to the invention in that the absorbent in the liquid phase better the Substance exchange can take place as in the solid phase, since the exchange of substances runs much more intensely and faster in the liquid phase.

It proves to be particularly advantageous if, according to a further feature of the method according to the invention, the absorbent fed into the gasification reactor together with the coal and the mass transfer between the sulfur compounds and the absorbent carried out directly in the gasification reactor so that the exothermic heat of the gasification reactions is immediate used to liquefy the absorbent can be.

If the Verqasunqsreaktionen are carried out at temperatures above the slag melting point, alc goes further Added advantage that now the boladons, liquid absorbent in a simple manner together with .the liquid phase ouo can be withdrawn from the gasification reactor.

809820/0139

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It has been shown that the desulfurization efficiency is particularly good when the mass transfer between the Sulfur compounds and the liquid absorbent directly above or in the border area of a liquid slag bundle provided in the lower area of the gasification reactor takes place because of the highly turbulent flow conditions prevailing in this area, a particularly intimate turbulence and thus mixing between liquid absorbent droplets and the synthesis gas containing the sulfur compounds.

A calcium compound can advantageously be used as an absorbent, preferably calcium oxide (CaO) or potassium carbonate (CaCfK), are provided, the liquid compounds with the ash constituents of the coal at the temperatures present in the reactor which forms the exchange of substances with targeted basicity management cause. In addition, lime is readily available and economical applicable.

Just as advantageously as the use of calcium compounds, alkali compounds, for example Na ₂ O, Na ₂ CO, K ₂ O, K ₂ CO-, etc., can be used as absorbents. These also have a pronounced affinity for sulfur, so that a particularly high degree of desulfurization can be expected. It is also possible to add mixtures of such absorbents.

It also offers advantages to regulate the viscosity of the slag produced with further additives so that it does not is too thin and foams, but is also not so viscous that it can no longer be removed. As such additives offer iron oxides and / or quartz sand, for example.

809320/0139

Saar mines ΑΠ

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The invention is in the following on the basis of one in the drawing schematically illustrated embodiment explained in more detail.

The drawing shows a gasification reactor 1, in the lower region 2 lance-like feeds 3 for blowing in carbonaceous Dust protrude along with the gasification agents. The infeeds 3 are inclined slightly downwards so that the introduced gases and the carbonaceous dust create a highly turbulent multiphase circulation flow above an im Form the lower area of the reactor space accumulating slag bath 4. The slag itself is in an underlying one Water bath 5 withdrawn and the surface of the liquid Slag exceeds a specified height. The reaction of the coal dust with water vapor and oxygen takes place in particular in the hot zone just above the slag bath 4.

The synthesis gas formed escapes at outlet 6 from the gasification reactor and is fed to a cyclone 7, which it leaves again at the outlet 8 in a dust-free state.

The reactor plant works as follows:

Through the lance-like feed lines 3 are in the lower region 2 of the reactor 1 gasification agents in the form of water vapor and oxygen and a carbonaceous dust blown in, to which an incombustible, finely powdered mineral additive is added. The gas pressure in feeder 3 must be so great that that it overcomes the internal pressure in reactor 1 in the amount of, for example, 25 to 30 bar.

The carbonaceous dust blown into the lower area 2 of the reactor, for example coal dust from Stoinkohlo, with heat development in Tompo doors of 1300 to 2200 C above the slag bath provided in the previous actuator. To image Jo is based on coal type synthesis gas with proportions of about:

809820/0139

.'beri) M / ei ke AG

55 % CO, 33 % H, 0.5% sulfur compounds, in particular H ₂ S, as well as CO «and H ₂ O.

The powdered one blown in with the coal dust Mineral additives, for example calcium oxide (CaO), come into intimate contact with reaction gases, their speed with the highly turbulent multi-phase circulation flow that predominates in this area up to 100 m / sec. can be. The calcium oxide dust, which is in the border area of the slag bath 4 with slag components, in particular with the SiO ", the aluminum oxide and / or the iron oxides liquid Forms compounds, reacts with the sulfur compounds contained in the synthesis gas and binds in this way the sulfur.

Instead of calcium compounds, alkali metal carbonates, for example soda (Na ₂ CO,) or potash (K ₂ CO,) can also be used. Both substances have a relatively low melting point and a high affinity for sulfur.

The slag produced during the gasification of coal contains, among other things, silicon, aluminum and iron compounds. Through the targeted addition of other mineral additives, such as. B. FeO, Fe ₂ O, and SiO ₂ , the coal dust, the viscosity of the slag can be influenced in such a way that it is not too tough to drain properly, but also not too thin that it foams or too many slag particles are entrained in the gas stream. In addition, a basicity level that is favorable for slag management and desulfurization can only be set in this way.

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e e r e i t e

Claims (9)

Claims 1.) Process for removing sulfur compounds, in particular HUS, from a synthesis gas which through Gasification of coal or other carbonaceous Solids in a Vergasunqsreaktor at elevated temperature arises, through mass transfer with a mineral-like absorbent, characterized in that the mass transfer with the absorbent predominantly takes place in the liquid phase. 2.) The method according to claim 1, characterized in that the absorbent in solid form with the coal in fed into the gasification reactor, liquefied by the exothermic heat released during gasification and in mass transfer within the gasification reactor is brought with the sulfur compounds. 3.) Method according to claim 1 or 2, characterized in that that the liquefaction of the absorbent immediately above or in the border area of a in the lower area the gasification reactor provided slag bath takes place. 4.) The method according to any one of claims 1 to 3, characterized gokonnzoichnet, that as an absorbent a calcium Vorbindunrj is provided, which with the slag constituents at ~ don Temperatures in the reactor forms liquid compounds. 603820/01 39 ORIGINAL INSPiSClED Saarbergwerks AG 5.) The method according to claim 4, characterized in that the calcium compound provided is calcium oxide (CaO) or calcium carbonate (CaCO,). 6.) The method according to any one of claims 1 to 5, characterized in that an alkali metal carbonate, preferably soda (Na ₂ CO-,) or potash (K ₂ C0-j) is provided as the absorbent. 7.) Method according to one of claims 1 to 6, characterized in that that coal and the absorbent are blown into the reactor chamber by means of a compressed propellant gas will. 8.) Method according to one of claims 1 to 7, characterized in that that coal, slag particles and absorbents in a highly turbulent multiphase circulating flow in the interior of the reactor room «/ earth. 9.) Method according to one of claims 1 to 8, characterized in that that other additives are added to the coal, which influence the toughness of the slag in the reactor chamber 809820/0139