DE2737669C3 - Process for the production of carbon monoxide - Google Patents

Description

characterized in that one

c) the zinc oxidizes to zinc oxide,

d) the resulting heat in the indirect heat exchange for the conversion of ZnO and C or for the evaporation of the zinc deposited according to b) and

e) returns the ZnO formed to reaction a).

2. The method according to claim 1, characterized in that the heat obtained in step d) in a heat cycle with zinc as the heat transfer medium of stage a) is fed.

3. The method according to claim 1, characterized in that one in step c) in a partial oxidation

c 1) some of the zinc with air to form a

first amount of zinc oxide and
c 2) some of the zinc with H2O to form a second amount of zinc oxide

oxidized and at least part of the heat developed in the oxidation stages c 1) and c2) returns to stage a).

4. The method according to claim 3, characterized in that at least part of the animal first and the second oxidation stage (el), (c2) in indirect heat exchange with and within the Zinc oxide-carbon reaction stage a) is carried out.

This invention relates to a process for producing carbon monoxide by gasifying a solid Carbon source.

The gasification of solid carbon sources has been known for many years. In one process, coal is used and contacting steam under elevated temperature conditions to produce a gas which is present in the consists essentially of carbon monoxide and hydrogen (synthesis gas). The process of gasification of coal are of great interest as they offer a number of advantages, such as using the coal in one way that is clean for the environment, the production of a gas with a high calorific value, the natural gas can replace, and the production of a gas of low calorific value, which is used as synthesis gas for the subsequent conversion into hydrocarbons or chemicals or as fuel is suitable.

The introduction of air in contact with coal in a coal gasification process is generally undesirable, since large volumes of nitrogen have to be handled in such a process. These nitrogen masses have no function in the process, but add to the process costs and also to the size and the cost of the plant. It is therefore desirable to have a process for the conversion of To have coal in carbon monoxide available, essentially without direct application of air can be carried out.

It is known that in the manufacture of zinc

ι »by reducing zinc oxide with carbon carbon monoxide is formed, cf. B. US-PS 7 99 743. You also have mixtures of carbon monoxide, Hydrogen and zinc through the reaction of hydrocarbons, especially methane, with zinc oxide generated, cf. B. U.S. Patent 1,899,184.

The object of the invention is to convert zinc oxide and coal for the production of carbon monoxide to be used to generate carbon monoxide from the otherwise common ballast of atmospheric nitrogen

2i) and enable a more selective and economical production of carbon monoxide.

According to the invention, this object is achieved by a method in which one

2-5 a) converts a solid carbon source in a reaction zone at a temperature range of 910 to 1540 ⁰ C with zinc oxide to zinc and carbon monoxide,
b) separates zinc from the gas and the carbon

jn noxid isolated;

this method being characterized in that one

c) the zinc oxidizes to zinc oxide,

d) the resulting heat in the indirect heat exchange for the conversion of ZnO and C. or for the evaporation of the zinc deposited according to b) and

e) returns the ZnO formed to reaction a).

In this process, the circulated zinc acts as an oxygen carrier, causing a dilution of carbon monoxide by nitrogen is eliminated. The method also offers the advantage that the Zinc oxidation heat released by indirect heat exchange for the endothermic oxidation of the Carbon source through which zinc oxide is made available. Finally, through the circulation

■ 10 of the zinc and the indirect heat exchange vary the process manifold, so that the optimal Conditions for selective production of carbon monoxide depending on the type of Carbon source are easily adjustable.

The conversion time for the reaction between the carbon source and the zinc oxide varies generally between 5 minutes and 2 hours. This reaction time depends of course on the temperature, the size of the carbon particles and the zinc oxide particles and the intensity of stirring in the Reactor off.

The zinc oxide is preferably used in finely divided form. These particles can have such a particle size that they go completely through a mesh screen with sieve openings of 0.35 mm. Smaller ones Particles can be used well. Larger particles tend to slow down the reaction. There the reaction between the carbonaceous material

rial and the zinc oxide is endothermic, higher temperatures generally lead to the reaction time abbreviate.

The reactions occurring in the process are generally solid / solid reactions, so that the pressure is not critical. In general, however, the pressure is slightly above atmospheric Pressure, for example in the range of 102 to 446 kPa.

A heavy carbonaceous material such as coal, coke, charcoal, restoi, Tar or asphalt preferably used in the invention. Among these carbon sources are throat, Coke, and charcoal are particularly preferred at present. As solid carbonaceous sources here are such denotes that solid at temperatures up to 1373 ° C are. The solid carbon sources are preferably used in finely divided form. They preferred Particles less than about 0.4 mm in diameter. This particle size refers to the longest Dimension of the single particle.

The method according to the invention can be used with advantage to generate solid carbon sources which solid residues from other gasification or liquefaction reactions from other carbon sources, such as coal, shale, oil or residual oil are to be gasified and converted into carbon monoxide.

The relative amounts of the zinc oxide and the carbon source can vary widely. In general, ZnO used as an oxygen donor is used in such an amount that there is a small excess of available oxygen atoms per available carbon atom. A range of 0.9 to 1.2 moles of ZnO, preferably about 1 mole of ZnO per gram atom of carbon in the Carbon source can be used to advantage.

In the zinc oxidizer, zinc is exposed to an oxygen source in an exothermic reaction Burned formation of ZnO. Examples of such oxygen sources are air, water vapor, with oxygen enriched air, oxygen. Air is the preferred source of oxygen. In general, the Amount of oxygen used in amounts above the stoichiometric requirement. Are preferred in the Oxidation mixture of zinc and oxygen has about 1.05 to about 1.25 atoms of available oxygen per Zinc atom used.

Typically, the carbon source and the zinc oxide are both distributed in a reactor mixed to a reaction mixture. The reaction mixture is utilizing the in the The heat released by zinc oxidation is heated to the reaction temperature in indirect heat exchange and continuously stirred either mechanically or d-jrch a fluidized gas, with as fluidizing gas preferably carbon monoxide and equilibrium amounts of carbon dioxide are used. From the reactor a gas containing carbon monoxide, zinc and equilibrium amounts of CO2 is withdrawn. The relative Amounts of CO and CO2 in the gas depend on the reaction conditions and the relative amounts of the in carbon source and ZnO introduced into the reactor. Under "Equilibrium Amount" or "Equilibrium Amount" CO2 is understood to be a CXV concentration that is released into the gaseous discharge from the Reactor is present at the specific conditions. From the bottom of the reactor will be ashy Solids withdrawn. The aforementioned gas is separated in a gas stream which consists essentially of Carbon monoxide and a liquid zinc stream, the stream preferably being sufficient is cooled to condense the zinc. The zinc stream is in a facility for oxidation -. of zinc is oxidized with oxygen to form zinc oxide and the zinc oxide formed is re-incorporated into the Reaction zone introduced.

In the invention, it is particularly advantageous that the temperature conditions in which a very good Yield of carbon monoxide is achieved above the boiling point of zinc, so the process a gaseous zinc results, which are quickly separated from the gas mixture, reoxidize and return to Can lead reaction mixture

> The reoxidation of zinc can be carried out by bringing the zinc into contact with air under elevated temperature conditions. Man consequently uses oxygen from the air as the source of oxygen, with no nitrogen in the reaction zone to introduce, in which the CO is formed. As a result, the zinc serves as an oxygen carrier.

After removal of the zinc, the gaseous reaction mixture consists essentially of Carbon monoxide with small amounts of carbon dioxide.

Hydrogen and light hydrocarbons. After adding more hydrogen, this gas can eventually used for numerous procedures.

such as for the Fischer-Tropsch process.

The invention can also be a non-volatile one

in carbon source, such as coke or coal, which contains a considerable amount of sulfur, for example up to to about 8 wt .-%, use in conjunction with zinc oxide as an oxygen donor. The thereby obtained Carbon monoxide is essentially sulfur-free since the

3) sulfur contained in the carbon source in Zinc sulfide is converted, possibly also a combination with the components of the Ashes enter. These sulfur conversion products are removed from the reactor with the ash

· »<> Deducted. That introduced into the ashes in this way Zinc can easily be recovered using standard roasting methods. The is particularly effective Production of CO from sulfur-rich carbon sources at a temperature above the subliminal

4s tion temperature of ZnS, which is 1185 ° C. then contains the gaseous reaction mixture from the reactor ZnS in addition to CO and Zn. This ZnS can from the gas stream by condensing at a temperature between the boiling point of the zinc

) 0 and the sublimation temperature of ZnS. The recovery of zinc from this ZnS can then be done through the ashes without dilution. Further details and preferred embodiments of the invention will be explained with reference to the drawings which show:

Fig. 1 is a flow diagram which explains the basic features of the invention,

Fig. 2 is a flow diagram showing an advantageous heat balance system for the invention,

F i g. 3 is a flow diagram showing a variant of the heat balance system from FIG. 2 shows

Fig. 4 is a flow chart showing a modified embodiment of the invention,

Fig. 5 is a flow chart showing another variant shows the method according to the invention,

Fig. 6 is a flow chart showing a modified embodiment of the invention in which a new Temperature control system is used,

F i g. 7 shows a variant of the system of FIG. 6,

F '. G. 8 a further modification of the method according to the invention, in which certain features are used for the separation of the by-products and the disposal of waste,

9 shows a modification of the method of the invention with an advantageous preheating stage,

Fig. 10 is a flow chart showing a further variant of the method according to FIG. 9 explained.

Fig. 1 is a schematic flow diagram for the basic method for converting a carbonaceous source into carbon monoxide according to the invention. The carbonaceous material is fed into the main reactor 1 through a heat exchanger 2 supplied via line 3. Zinc oxide is fed into the main reactor 1 via line 4. The firm ones Materials are mixed in the reactor 1 by a fluidizing stream of carbon monoxide, wherein this stream enters via the two rings 5 and 6. Carbon monoxide is given to these rings 5 and 6 via the Line 7 supplied from a carbon monoxide source 20. The carbon monoxide gas is in the furnace 8 beforehand has been heated so that this gas supplies the heat required for the reaction. In the lower part of the reactor 1, the ash collects and is drawn off via line 9. Carbon monoxide and zinc and the gaseous by-products also go through a cyclone separator 10, which carries the Solids are separated from the gaseous outlet, and the solids-free gases are passed through the line 11 withdrawn from the reactor. The one in the cyclone separator 10 separated and entrained solids fall back into the reactor bed.

The gas. which consists essentially of carbon monoxide and zinc, is from the main reactor 1 via the Line 11? U a zinc capacitor 12 guided in the this gas is brought into indirect heat exchange with a stream of air which, via line 13 is fed.

In the zinc cooler 12, the gaseous zinc is liquefied and separated from the CO gas via the line 14 is obtained as a process product.

The liquid zinc obtained in the zinc cooler 12 becomes withdrawn via line 22 and into the zinc oxidation device 23 introduced. In this oxidizer, the liquid zinc is treated with an air stream that was preheated in the zinc cooler 12, together with additional air introduced via line 24 is brought into contact. The zinc becomes solid Zinc oxide in the zinc oxidizer 23 is oxidized and the remaining gas. essentially nitrogen, is made from the Zinc oxidizer 23 withdrawn via line 25. This gas is indirectly passed through the heat exchanger 2 led to preheat the carbonaceous raw material. Solid zinc oxide is finely divided in a «! · State from the bottom of the zinc oxidizer 23 via the line 4 discharged and is introduced into the main reactor 1

Three experiments were carried out in which 132 Grams of charred material are introduced into a tubular quartz reactor.

The amount of charred material corresponds to one gram of carbon. In the quartz reactor Zinc oxide was also introduced as an oxygen donor. The char and the oxygen donor Both were used in finely divided form, namely with a particle size corresponding to one mesh opening from 035 mm. The weight ratio of the oxygen donor to the char was as follows chosen that there was about one atom of oxygen per carbon atom. The reactor was open Connection to a gas collector and analyzer. The reactor was then referenced in the table

-, heated to specified temperatures and kept at this temperature by continuing the heating until the evolution of gas had ceased.

This took about 45 minutes. The results of the analysis of the gaseous waste are

can be seen in the following table:

Reaklorlcmperalur
ι

7nO: coal

Weight

reliallnis

cn / cn-

Molverhallnis im
Product gas

CO-liquidation liier CO pm Ciramm
Money*)

1040
1085
1132

5.13
5.13
5.13

20.3
37.4
32.3

1.54
1.67
1.84

*) The theoretical CO output is 1.87 liters per Grams of coal.

From these results it appears that the

2 ", charred material or the coal effectively under Using solid ZnO as an oxygen donor can be gasified. The results also show that a higher reaction temperature gives a higher yield of carbon monoxide.

In Fig. 2 an embodiment of the invention is explained with a heat cycle, in the indirect Heat exchange devices in the reactor and in the zinc oxidizer are connected to one another by a loop are. In this heat exchange loop, a fluid heat exchange medium is circulated around the to transfer heat formed in the zinc oxide to the reactor, in which the endothermic reaction between the carbon source and the zinc oxide takes place The zinc oxide produced in the zinc oxidizer becomes introduced into the reactor for further reaction with the carbon source

Particularly suitable fluid media for the heat exchange in the invention are those that easily the temperature at which the carbon monoxide is formed by the reaction of the carbon source and the zinc oxide can be kept liquid and in the vapor phase at the temperature of zinc oxidation can be held. Examples of such fluid media are molten metals and salts. the

so preferred fluid media for heat exchange are zinc, sodium, potassium and mixtures of Sodium and potassium. The pressures at which the heat exchange loop is preferably operated is around To obtain advantageous results, these fluid media are chosen such that at the temperature are liquid in the formation of carbon monoxide and in vapor form in the formation of zinc oxidation. These Pressures are given below for individual heat exchange media:

Heat exchange medium

Pressure range kPa

Zn 170-345 N / A 170-345 K 550-895 Na + K 275-690 (50/50 weight ratio)

The preferred fluid heat transfer medium is zinc. It is particularly advantageous to use this metal as a heat exchange medium because it is completely compatible with the overall process at every stage. This creates a small leak that can occur in the heat exchange loop in the main reactor in the carbon monoxide is formed, or in the zinc oxidizer does not significantly affect the efficiency of the overall process.

The fluid heat exchange medium from the heat exchange device in the zinc oxidizer to of the heat exchange device flowing in the reactor can flow through a third heat exchange device and be conducted in indirect heat exchange with at least a part of the zinc that comes from the from the Reactor originating gas is separated. The third heat exchange device is used, for example, to complete evaporation of the liquid zinc before further use.

The zinc stream separated from the gas leaving the reactor is generally more liquid Form exists and has a temperature lower than but near the boiling point of zinc. The liquid zinc is preferably evaporated before it is used further. To do this, one can some or all of the liquid zinc in indirect heat exchange with that withdrawn from the reactor Bring gas and / or with the fluid heat exchange medium from the Wärmeaustauscheinrichlung flows in the zinc oxidizer to the heat exchange device in the reactor and / or with a externally arranged fluid heating medium.

When a completely separate heat exchanger loop between the reactor and the zinc oxidizer is used, the liquid zinc stream, which is separated from the gas leaving the reactor is carried out, preferably by indirect heat exchange with the gas leaving the reactor, and thereafter with the fluid heat exchange medium leaving the heat exchange device of the zinc oxidizer.

The stream of vaporized zinc is introduced into the zinc oxidizer to be oxidized to zinc oxide will. If necessary, a carrier part of this X.invapor stream can be introduced into the zinc oxidizer instead to be introduced into the line for transporting the zinc oxide of the zinc oxidizer to the reactor will. In addition, a fluidizing agent can optionally be used Part of the zinc vapor stream is introduced into the lower part of the reactor to produce the reaction mixture, which contains a solid carbon source and the solid zinc oxide to fluidize.

If the zinc itself is the fluid heat exchange medium is in the warm-up loop, so it is preferred heat exchanger loop between the reactor and the zinc oxidizer not completely removed the other method separately. In this embodiment it is preferably the liquid zinc in two Steps to separate from the gas leaving the reactor, so that a first and a second liquid Zinc stream is produced. Each of these two separation stages is generally carried out by passing the gas through the Cooler and the separator is performed. The first liquid zinc stream is divided into an oxidizer part and a Carrier part separated The oxidizer part is fed into the zinc oxidizer via an evaporator. The carrier part is combined with and through a circulating fluid heat exchanger zinc the heat exchanger device passed in the zinc oxidizer is essentially the same amount of Zinc, as added to the fluid zinc in the heat exchanger loop, downstream of the Deduced heat exchanger device, which is connected to the zinc oxidizer, and before the zinc into the Heat exchanger device enters the reactor. The separated zinc vapors are used as a carrier gas used to carry the zinc oxide from the zinc oxidizer to the reactor. The second liquid zinc stream is in indirect heat exchange with the gas

ίο brought that leaves the reactor to this second to vaporize liquid zinc stream. The zinc vapor stream obtained is finally compressed also fed to the zinc oxidizer.

According to the schematic flow diagram of FIG. 2, a carbon source ' introduced from a cooling fluid supply 30 via line 31. Zinc oxide is also used in the main reactor 1 introduced via line 32. The main reactor is equipped with a first indirect heat exchange device 33 equipped. The reaction mixture in reactor 1 is fluidized by zinc vapors entering the reactor be introduced through the fluidizing ring 34. The reaction of the carbon source with the zinc oxide produces a gaseous mixture which is withdrawn via line 35 and the carbon monoxide and contains zinc. The reaction also produces a solid residue that contains ash and over which Line 36 is withdrawn from the bottom of the reactor. The gaseous mixture is passed through a heat exchanger 37 and a cooler 38 to a gas-liquid device 39. From the separator 39 a gas containing a substantially zinc-free carbon monoxide is withdrawn through line 40. A liquid zinc stream is drawn off from the bottom of the separating device 39 via the line 41. This liquid stream is through the heat exchanger 37 in indirect heat exchange with the above the line 35 brought from the reactor 1 withdrawn gas. This cools this gas and the zinc is at least partially condensed and the liquid zinc in line 41 is heated and at least partially evaporated.

The zinc stream leaving the heat exchanger 37 is conducted via the line 42 to the indirect heat exchanger 43, in which the zinc is completely evaporated by the fluid heat exchange medium which circulates in the heat exchange loop explained below. The vaporized zinc stream leaving the heat exchanger 43 is split into three parts. The main part goes through line 44 into zinc oxidizer 23. A second part or carrier part goes through line 45 in rerunning _with the zinc oxide in line 46 and this conveys the zinc oxide back into reactor 1 via line 32.

A third part or a fluidizing part of the zinc vapor goes through the line 47 into the ring 34, from where it is blown upwards and brought into contact with the solid materials of the reactor 1 to fluidize them.

The zinc vapor stream introduced into the oxidizer 23 via the line 44 is treated with an oxidizing agent, introduced via line 48. This oxidizing agent may be a Any oxidizing agent that converts zinc into zinc oxide, but air or water vapor is preferred. Solid, finely divided zinc oxide becomes in the oxidizer 23 produced and transferred via line 49 into a calming container 50 A gaseous product,

230 215/385

which consists essentially of nitrogen, when air is used as the oxidizing agent, leaves the zinc oxidizer over line 51.

In this embodiment of the invention, a closed heat exchanger loop between the Reactor 1 and the zinc oxidizer 23 used. In the zinc oxidizer is a second heat exchanger coil 52 arranged and through a loop with the first heat exchanger coil 33 in the reactor 1 via a Pump 53 connected. Part of this heat exchanger loop is the heat exchanger 43. In FIG Coil 52 becomes a fluid heat exchange medium, preferably a liquid introduced via line 54 Metal, vaporizes through the heat developed in zinc oxidizer 23 during zinc oxidation. That evaporated fluid heat exchange medium is via line 55 through the heat exchanger 43 and the Line 56 is routed into heat exchanger coil 33. The fluid heat exchange medium is in this queue cooled and gives both the latent and the sensible heat to the reaction in reactor 1 for the formation of carbon monoxide. The liquid heat exchange medium is from the coil 33 over line 57 withdrawn and returned to coil 52 by pump 53.

The heat exchanger loop containing the heat exchange coils 33 and 52 can be zinc or Any other fluid heat exchange medium can be used. The heat exchanger loop may have a device not shown in the drawing to compensate for the heat exchange. These Compensating device is used to supply or remove heat, so that the system the heat and Maintains temperature balance.

In the flow diagram of FIG. 3 zinc is used as a fluid heat exchange medium in the heat exchanger loop is used because this system does not have a closed heat exchanger loop, but rather a flow of zinc into and out of the heat exchanger loop takes place, such as this will be explained in more detail.

Basically this is shown in FIG. The system shown in FIG. 3 is very similar to that of FIG. It relate the same number symbols on the same items. The gas leaving the reactor 1 via line 35 is passed through the heat exchanger 37, the two heat exchange paths on different channels Be shown in the drawing. These two parts of the heat exchanger 37 are actually closer Connection with each other so that the heat exchange between the liquid zinc stream and the gas can be brought about. The gas leaving the heat exchanger 37 is passed through a first Cooler 38 'and a first gas-liquid separator 39 'The gas leaving the first separating device 39' is passed through a second cooler 38 " and a second gas-liquid separator 39 ″. The gas leaving the separator 39 ″ is finally passed to a unit 58 for quenching and washing with water via line 59 and the gas stream is here cooled with water introduced through inlet 59 'to remove traces of zinc to remove. The gas containing carbon monoxide leaves unit 58 via line 60 and water, containing traces of zinc, leaves the unit 58 via line 61. The liquid zinc stream which the Separating device 39 'via the line 41' at the bottom is left by the pump 62 to the further Processing promoted. This liquid zinc stream leaving the pump 62 becomes a part to be oxidized divided in line 63 and a carrier part in line 64.

The liquid zinc portion in line 63 passes through an evaporator 64 '. The evaporator 64 'can use its heat received by being immersed in the oxidation reactor 23. Similarly, the Zinc stream on line 41 "after passing through the

ίο heat exchanger 37 'has gone, for example in indirect heat exchange with the gas leaving the reactor 1 via line 35, the heat exchanger 37 'as zinc vapor. The two zinc vapor streams in lines 65 and 65 'are in line 44 combined and introduced into the zinc oxidizer 23 with line 53. The zinc vapor stream in line 65 'becomes passed through a zinc vapor compressor 66 so that both zinc vapor flows in lines 65 and 65 'the have the same pressure.

The carrier portion of the liquid zinc stream in line 64 is placed in a liquid zinc vessel 67. The liquid zinc that leaves the cooling coil 33 also comes into the vessel 67. In addition, the zinc required for replenishment is introduced into the vessel 67 via the line 68. The liquid zinc is removed from this vessel via line 69 by pump 70 and passed through heat exchanger coil 52 via line 71. A carrier part is withdrawn via line 45 from the zinc vapor stream leaving the heat exchanger coil 52 in lines 55 and 2. The amount of zinc stream withdrawn from the heat exchanger loop via line 45 is essentially the same as the sum of the zinc streams introduced into vessel 67 via lines 68 and 64. The zinc vapor stream in line 45 serves as the carrier gas for carrying the zinc oxide from the zinc oxide collecting vessel 50 back to the reactor 1. This vaporizes the carrier portion of the liquid zinc from the line 64 in contact with the fluid heat exchange medium in the heat exchange loop

In another embodiment of the invention, the liquefied zinc from the disposal of the Gasification reactor in indirect heat exchange through the heat generated by zinc oxidation evaporated to produce a zinc vapor stream associated with an oxidizer in a zinc oxidation zone is brought into contact for the production of zinc oxide. This zinc oxide is then put back into the

so introduced for main reactor as a source of oxygen for the main reaction to the formation of carbon monoxide the evaporation of part of the zinc can be the heat of the gasification reactor leaving Use product current.

The re-evaporation of the liquefied zinc to convert it to zinc oxide has the advantage of rapid and complete oxidation of the zinc and easy separation of the zinc oxide from it Gas stream leaving the zinc oxidation zone by passing the mixture of zinc oxide and gas through it Separation devices for gases and solids leads, such as filters, centrifuges or cyclones, whereby the centrifuges are preferred. In addition, there are no problems caused by the deposition of zinc oxide on the surfaces of Zinc drops on.

In this embodiment of the invention, a gaseous outlet from the reactor, the carbon monoxide and contains zinc, in indirect heat exchange

be brought with the separated, liquefied zinc. This becomes part of the liquefied zinc re-evaporated and the corresponding gaseous outlet is cooled and a portion of the gaseous Zinc is liquefied. The partially re-evaporated zinc is in indirect heat exchange with the Mixture of zinc and the oxidizing agent brought into the zinc oxidation zone. This will do the rest of the liquid zinc evaporates and the zinc vapors are extracted from this indirect heat exchange and introduced into the zinc oxidation zone. In this form of management, the tangible and the latent Heat of the gaseous discharge from the reactor and also that in the exothermic zinc oxidation stage effectively used heat generated, thereby reducing the amount of external energy required in the Procedure is reduced to a minimum.

4 illustrates this embodiment of the invention. A means 30 for the carbon source is connected to reactor 1 via line 31.

Zinc oxide is fed to reactor 1 via line 4. The ashes are discharged via line 36 deducted. The gaseous reaction product consists essentially of carbon monoxide and zinc and is withdrawn from the reactor via line 11. Since the Conversion between zinc oxide and carbon to form carbon monoxide and zinc an endothermic one In response, heating devices such as a heating coil 80 are present.

The gaseous mixture from line 11 is passed through the indirect heat exchanger 81, the cooler 82 and the gas-liquid separator 83. In the heat exchanger 81 and in the cooler 82 the zinc vapors are essentially completely liquefied.

In the separating device 83, the liquid zinc is separated from the gas containing the carbon monoxide, which gas is drawn off via the line 84. Liquid zinc is withdrawn from the bottom of the gas-liquid separator 83 via line 85. With the aid of the pump 86, the liquid zinc is passed through the heat exchanger 81, the line 87 and the heat exchange coils 88, where it is vaporized and finally fed to the zinc oxidizer 23. An oxidizing agent, such as air, is also introduced into the zinc oxidation zone 23 via line 24

In the zinc oxidizer 23, the zinc that has been re-evaporated by the heat exchanger 81 and the heat exchange coils 88 is reacted with oxygen to form zinc oxide. Some of the heat developed during the oxidation reaction is used to vaporize zinc in the heat exchanger coil SS. Gas is withdrawn from the zinc oxide 23 via line 89. This gas consists essentially of nitrogen, if air has been introduced as an oxidizing agent via the line 24. Finely divided solid zinc oxide is drawn off from the zinc oxidizer 23 via the line 4. This zinc oxide is introduced into the reactor 1 again

In another preferred embodiment of the invention, at least part of the first and the second oxidation stage in indirect heat exchange with and within the zinc oxide-carbon reaction stage carried out F i g. Fig. 5 illustrates such an embodiment. Finely divided carbon is fed into reactor 1 via line 31 from a carbon source 30 supplied Finely divided zinc oxide is also introduced into the reactor 1 via line 90 Ash formed is drawn off via line 36. The final gaseous product consists essentially of carbon monoxide and zinc and is withdrawn from the reactor via line 11. This gaseous Mixture is divided into a product stream 91 and a recycle stream 92. The recycle stream 92 becomes again introduced into the lower part of the reactor 1 via the pump 93 and serves as fluidizing gas for the reaction mixture.

The product stream 91, which consists essentially of carbon monoxide and zinc, is brought into the heat exchanger 94 in exchange for liquid zinc, wherein it is cooled and the vaporous zinc is partially condensed. In order to condense all of the zinc, the gas mixture from the reactor is brought from the heat exchanger 94 into a cooler 95 in which most of the zinc which is still in the vapor form is condensed. In the separating device% the liquid zinc is separated from the gaseous mixture, which is drawn off through the line 97. The liquid zinc is withdrawn via line 98 and sent via pump 99 and line 100 through heat exchanger 94, where the zinc is at least partially evaporated and via line 101 in contact with an oxidizing agent, such as air or water vapor, which passes through the Line 102 is introduced, is brought. The zinc / oxidizer mixture is converted to zinc oxide as it passes through the heat exchanger coils 103 located on the

jo inside the main reactor 1 are arranged, passes through it. The mixture of solid zinc oxide and gas is passed from the heat exchanger coils 103 into a cyclone 104 , from where an exhaust gas which is free of zinc oxide particles is discharged via line 105. The solid, finely divided zinc oxide is drawn off from the lower part of the cyclone 104 and brought into the reactor 1 via the line 90. The zinc oxide required for replenishment is introduced via line 106 .

In another preferred embodiment of the invention, the in the reoxidation of zinc ¹ ; The heat released into zinc oxide varies without changing the amount of zinc oxide circulated. For this purpose, part of the zinc is oxidized with air to form a first amount of zinc oxide and part of the zinc is oxidized with H2O to form a second amount of zinc oxide and at least part of the heat developed in these oxidation stages is returned to stage a) of the process according to the invention, in which a solid carbon source is reacted with zinc oxide.

In a process in which zinc is converted into zinc oxide with air alone, this yields Reuxidaiiuri im essentially a constant amount of heat per unit of reoxidized zinc. Without the amount of To change the zinc oxide produced, the amount of heat generated cannot be changed either. As a result, the temperature in the reaction which forms the carbon monoxide cannot be varied without

bo is the amount of zinc oxide produced by zinc oxidation in heat exchange with the CO formation reaction is going to change. According to this embodiment of the invention, this variation is possible because the pro The heat generated by the moles of zinc oxide formed depends on whether the oxygen source is air or water is used. The amount of heat released by the oxidation of a given amount of zinc with air is higher than the amount of heat used in the oxidation of the

same amount of zinc occurs with water. It may depend on the proportion of the first and as a result the second type of oxidation, the total released by oxidation of a given amount of zinc Heat can be adjusted, changed or controlled, without changing the total amount of oxidized zinc. This allows a thermally neutral System can be set up in which the heat released in the exothermic zinc oxidations in the essentially the heat requirements of the endothermic carbon oxidation reaction plus the heat leakage of the system is met.

Another advantage of this invention is the production of relatively pure hydrogen as a by-product. This hydrogen can be used with part of the CO produced to produce methanol or Methane can be combined. The hydrogen can also be used or sold as such.

The relative amounts of zinc that are reoxidized with air or with water depend on the effectiveness the heat transfer from these exothermic oxidation reactions to the endothermic reaction Formation of carbon monoxide. Typically the ratio of the first fraction of the total zinc is the It is reoxidized with air to the zinc to be reoxidized with water in the range from 1.1: 1 to 6.0: 1. Most preferably, the zinc-zinc oxide reactions of this invention are carried out in a cyclical manner, wherein the zinc oxide, which is formed in both oxidations of the zinc with air or with water, into the Main reaction for the production of carbon monoxide is re-fed. The two zinc oxide streams can be used separately or in combined form or together in the reaction to form carbon monoxide to be introduced.

The splitting of the zinc stream into two streams for separate reoxidations can be anywhere downstream from the main reaction for the formation of carbon monoxide. The gaseous finish from the Reactor can be split into two streams which are individually split into a carbon monoxide and zinc stream as a first stream and a second zinc stream for the two reoxidation reactions. Alternatively can convert the entire gaseous product into a gaseous carbon monoxide stream, the reaction product and a liquid zinc stream are separated. This liquid zinc stream is then divided into two liquid streams divided up individually on the one hand for reoxidation with air and on the other hand for reoxidation can be used with H2O.

In one embodiment according to the invention, the gaseous product stream is consequently fractionated, to form a stream of liquid zinc and a stream of carbon monoxide. The zinc stream is in divided a first and a second portion. The first portion of the zinc stream is in a first Oxidation zone oxidized with air. The second portion of the zinc stream is in a second oxidation zone with H2O oxidizes. Between the reaction zone and the an indirect heat exchange is established in the first and the second oxidation zone.

A particularly effective heat exchange can be achieved by using at least a portion of both the first and the second oxidation zone, in indirect heat exchange with that mentioned above Reaction zone is brought. This can be achieved by looking at the first and the second Oxidation zone as such within the reactor, in which the reaction leads to the formation of carbon monoxide takes place, arranges

One of the main advantages of this embodiment of the invention is the ability to control the Reaction temperature for the formation of carbon monoxide. To carry out d'ese temperature control it is necessary to Time preferred to determine the heat required for the reaction to form carbon monoxide and to regulate the ratio of the two zinc streams depending on the heat demand. More specific Expressed this means that the ratio of the zinc stream oxidized with air to that with water oxidized zinc current is increased when the heat required for the formation of carbon monoxide increases and vice versa

In one embodiment of the invention, the temperature of the reaction between the carbon source and the zinc oxide are scanned, thereby generating a signal for the reaction temperature.

Then the flow or gushing of the first portion becomes of the zinc, or the flowing or flowing of the second portion of the zinc, or both, depending on This control signal regulated so that the temperature in the reaction zone developed by controlling the The amount of heat used to control the total oxidation of the zinc.

In the embodiment of the method according to the invention according to FIG. 6, a main reaction vessel 1 is present, into which carbonaceous material is fed via line 31 from a source 30. Zinc oxide is also introduced into the reaction vessel via line 4. The gaseous reaction mixture leaves the reactor 1 via line 110 and consists essentially of carbon monoxide and zinc.

A first oxidation unit 113 and a second oxidation unit 114 are present in the reaction vessel 1 in indirect heat exchange with the materials in the vessel. The reaction mixture from line 110 goes via line Ii 15 into a condensation and separation unit 116 and some of it goes back to reactor 1 via a pump 111 and line 112. The condensation and separation unit 116 has an indirect heat exchange device 117 and a gas / liquid separation device 118 and a pump

119. In the heat exchanger 117 , the liquid zinc effects a pre-cooling of the gaseous reaction mixture in line 115. As a result, the liquid zinc is at least partially evaporated again. Gas consisting essentially of carbon monoxide leaves the separating device 118 via the line 120. The liquid zinc is conducted from the separating device 118 via the pump 119 through the heat exchanger 117 . Optionally, a wide ^r e evaporation apparatus (not shown in the drawing) can be provided for the evaporation of zinc, it can be installed downstream of the heat exchanger 117 into the conduit zinc 121st The zinc stream is then passed through a three-way valve 122 where it is split into a first stream 123 and a second stream 124.

The first stream 123 is mixed with air from an air source 125 and the mixture of zinc and air is fed into the oxidation unit 114 via line 126 . In this oxidation unit the zinc and the air react to form essentially zinc oxide and nitrogen. The product from the oxidation unit 114 is passed via the line 127 to a separating device 128, such as a cyclone. In this Cyclon 128 the solid zinc oxide is on the bottom

collected and the gas consisting essentially of nitrogen leaves the cyclone 128 via the Line 129.

Similarly, the second portion of the zinc stream flowing via line 124 is made up with water mixed preferably in Fonr. of Wtisserdampf, that of a water source 130 originates The mixture of water vapor and zinc goes through the line 131 in the second oxidation unit 113, where this mixture is exothermically converted into zinc oxide and hydrogen will. The zinc oxide / hydrogen mixture goes through line 132 into a gas / liquid separator such as a cyclone 133. The exhaust gas, which consists essentially of hydrogen, leaves the cyclone via the Line 134.

The zinc oxide leaving the cyclones 128 and 133 via lines 135 and 135 'is in line 4 mixed and in the reaction vessel 1 as an oxygen donor for the reaction to form carbon monoxide directed

A sensing device 136, such as a thermocouple, measures the temperature and generates a corresponding one Signal. A control device 137 compares this signal for the reaction temperature with a specified one Signal from a source to set the signal 138 and generate a corresponding control signal 139. This control signal operates the three-way valve 122 in such a manner that the relative amount of zinc that flows into the first oxidation unit 114 is increased when the sensed by the thermocouple 136 Temperature is below the set temperature. In a corresponding manner, the relative Amount of zinc flowing through the second oxidation unit 113 is regulated when the temperature is above the the specified point

Another embodiment of the method according to the invention is shown in FIG. 7 shown in this system instead of one reactor, two reactors 1 a and 16 are used, in which the carbonaceous material is reacted from the source 30a or 306 with zinc oxide, which is introduced via the line 4a or 46, to form carbon monoxide and zinc vapor. This gas mixture is supplied via lines 110a and 1106 deducted. In a similar way, a direct circulation flow of the waste gas is provided, the is introduced as fluidizing gas by pumps Uta and 1116 via lines 112a and 1126. in the The oxidation unit 114 is arranged in reactor la, whereas the oxidation unit 113 is arranged in the reactor 16 is arranged. The gaseous ones leaving the two reactors via lines 115a and 1156 Reaction mixtures are combined and stored in the separation unit 116, which is the same as in FIG. 6 (31-33) A gas stream is obtained which exits via line 120 and consists essentially of carbon monoxide exists, and a zinc stream that goes off via line 121. This zinc stream is then used in a first Stream 123 for reoxidation with air from air source 125 and a second zinc stream in line 124 for reoxidation with a stream of water from the wi Get water source 130. Two valves 122a and 1226 are provided to control the relative amounts of the in the to control the two oxide ion units flowing zinc. The two zinc oxide outlets of the two Cyclone 133 and 128 are connected by a line 140. Since the μ the heat generated by the oxidation of the zinc with water per mol of zinc is less than the amount of heat, The one produced by the production of one mole of zinc and one mole of carbon monoxide is a larger one Amount of zinc to oxidize in the reoxidation unit 113 than that chemically required for the reactor 16 is necessary. Therefore, the excess of the in the Reoxidation unit 113 produced zinc oxide transferred via line 4 to the reactor la.

In another embodiment of the invention, the zinc levels would otherwise be in the ash by-product lost, easily recovered by treating the zinc-containing ash with hot air, these zinc contents are converted into zinc oxide. That obtained mixed with the ashes Zinc oxide is then used as a source of oxygen for the conversion of additional carbonaceous Material used to carbon monoxide in a secondary reaction zone from where a mixture of Carbon monoxide and zinc metal is removed. Zinc is separated from the carbon monoxide, back into Zinc oxide is converted and then returned to the primary reaction zone, where it is used for conversion of carbonaceous material in carbon monoxide is used

The reaction in the secondary reaction zone, in which the zinc content is in the form of zinc oxide Conversion of additional carbonaceous material to carbon monoxide is also used run at elevated temperature To ensure a high conversion of the zinc oxide, the Reaction in the second reaction zone preferably at a higher temperature for a longer period of time than that in the first reaction zone. An average response time of 5 minutes to 2 hours is generally sufficient.

In the second reaction zone, the zinc oxide should preferably be in finely divided form, as it is is used in the first reaction zone. If necessary, the ash-zinc oxide mixture can through a comminution device before it is introduced into the second reaction zone.

Since there is a desire to avoid losses of zinc in the secondary reactor by carrying on zinc contents in the ashes are preferred as carbon sources for the secondary reactor those with a very low sulfur content are used, especially those with a sulfur content below 0.01% by weight or those which are completely free of sulfur.

Zinc Shares milgeführl of the ash from the first reaction zone are contacted at a temperature in the range 1093 to 1650 ⁰ C in a second oxidation zone in contact with oxygen, to form a second quantity of zinc oxide. This recovered or regenerated zinc oxide which is in admixture with the ash is introduced into the secondary reaction zone in which a schwefclarme or sulfur-free carbon source is converted into carbon monoxide at a temperature in the range 910-1540 ⁰ C in carbon monoxide. The heating of the reaction mixture is achieved by indirect heat exchange between the oxidation reaction mixture, with the zinc particles carried along being converted into zinc oxide. A gas which essentially contains carbon monoxide and zinc vapor is withdrawn from the reactor. Solids containing an ash essentially free of zinc compounds are withdrawn from the bottom of the reactor. The carbon monoxide-zinc gas can be combined with the product gas from the first reactor.

This combined gas is then cooled and separated Into a stream of carbon monoxide and a stream of liquid zinc. The zinc stream that the recovered Contains zinc, is then reoxidized to zinc oxide and returned to the primary reactor.

As in Fig. 8 is shown being a hot charred Mass at a temperature of about 1093 ° C in the primary reactor 150 introduced via line 151 In this primary reactor is also finely divided Zinc oxide introduced through line 152. The solid materials are fed to reactor 150 through a fluidizing stream of carbon dioxide, carbon monoxide or a mixture of carbon monoxide and Carbon dioxide mixed, these gas streams being introduced into the reactor via line 153.

The loading of the reactor 150 with zinc oxide as an oxygen source at the beginning of the reaction takes place by one make-up zinc oxide through lines 154 and 155 through reaction zone 156 and finally through the lead 152 introduces

Ash collects in the lower section of reactor 150 and is withdrawn via line 157. Carbon monoxide and zinc and also other gaseous by-products are transferred from the reactor 150 The line 158 frees entrained solids. A cyclone, not shown, can be in the reactor 150 be arranged to separate entrained solids from the gaseous outlet of the reactor and they returned to the reactor bed. ,

The exhaust gas, which consists essentially of carbon monoxide and zinc, is through line 158 to Heat exchanger 159 led, where the gas by indirect heat exchange with liquid zinc from the Separating device or the phase separator 160 is condensed. In the separator 160, the liquid zinc separated from the CO gas. The product gas is carried on via line 161.

The liquid zinc condensed in the separating device 160 is drawn off via the line 161, through the Heat exchanger 159 led to the zinc by indirect heat exchange with the product gases of the Reactor to evaporate again, and then introduced into line 162. In line 162, the zinc is then added hot air (900 to 1650 ° C) via line 163 mixed. The resulting mixture is then added to the Reaction zone 156 passed via line 155, where the zinc is oxidized to zinc oxide. After the oxidation will the reaction mass passed via line 164 to separating device 165, where the gas content of the im consists essentially of nitrogen and excess oxygen, is discharged via line 166. Zinc oxide is withdrawn from the bottom of separator 165 via line 152 and into reactor 150 introduced.

The gaseous product stream, which is withdrawn from the separator 160 via line 161 and consists essentially of carbon monoxide and some carbon dioxide, can be treated in the heat recovery unit 167 in order to remove the heat for further use. The gas stream is then fed to a carbon dioxide absorber stripper 168 via line 169, where any CO _{2 present is} removed so that a product stream is formed which consists essentially of pure carbon monoxide. The CO ₂ is removed by the absorber stripper 168 and can be used via lines 171 and 153 to the main reactor for further use for fluidization in the reactor bed, or it can be vented via line 170 to the atmosphere. Ash-containing material containing entrained zinc compounds generally in the form of zinc sulfide is removed from reactor 150 via line 157 and brought into heat exchange with the interior of secondary reactor 173 via line 172. Hot air (900 to 1650 "C) is passed over line 174 is placed in line 172 in an amount sufficient to convert the zinc portions in line 172 to zinc oxide

H). The heat released during this exothermic reaction, through the heat exchanger section 175, helps to maintain the contents of the secondary reactor at the desired level. After the heat exchange of the starting materials entering the heat exchanger zone 175, the starting materials, mainly zinc oxide, ash and nitrogen, together with some air and CO ₂ via line 176 of the separating device

177 supplied from where the gaseous components, which essentially consist of nitrogen, air and carbon dioxide consist, are removed via line 178 and the solid particles, which are essentially a mixture consist of zinc oxide and ash and further oxidized coal, removed via line 179 and in the secondary reactor 173 can be introduced. A second batch of coal with a low sulfur content is introduced via line 180 into secondary reactor 172, which is operated in a manner similar to that of primary reactor 1 is operated, but generally at a higher temperature and longer reaction time. It An ash, which is essentially free of zinc components, now collects in the lower part of the reactor 173 and is withdrawn via line 181. Gaseous zinc and carbon monoxide are carried by the Solids withdrawn at the top via line 182 and in line 158 with the gaseous exhaust gases of the primary reactor 150 combined.

That from the separator 177 via the line

178 removed gas is led to the heat recovery unit 183. The cooled gas obtained is then passed via line 184 to COrAbsorber-Abstreifer 185, where a stream, which _{consists essentially of CO 2} , is separated and via line 186 for circulation via lines 187 and 188 to reactors 150 and 173 is led or led outdoors. Another gaseous stream 189, consisting essentially of nitrogen and air, is withdrawn from absorber stripper unit 185.

_{If SO 2 is} present in the system, a sulfur removal unit 190 can be used in line 186, _{obtaining essentially pure CO 2} -SUOm in line 187, and removing sulfur oxides or sulfur and oxygen from unit 190 via line 191 will.

The invention can also be designed so that the carbon source in a preheating stage with at least a part of the gas that is produced in the gasification zone is brought into contact. The carbon source is preheated in the preheating zone and zinc that is present in this part of the gas becomes condensed on the carbon source. The carbon source is then exposed to water vapor with the zinc, to oxidize the zinc to zinc oxide (oxidation zone), creating a mixture of the carbon source with Zinc oxide is formed. In the subsequent gasification stage, the carbon source and the Zinc oxide reacted (gasification zone), whereby a gas is formed that contains carbon monoxide and zinc. A

Part of the zinc is converted into zinc oxide in a zinc combustion zone by contacting the zinc with a gas. the Contains free oxygen, like air, is converted to the thermal energy of this zinc combustion zone used to at least part of the ί endothermic gasification reaction between the carbon source and the zinc oxide consumed heat to deliver.

There are several important advantages associated with the method according to this embodiment of the invention. The carbon source is preheated by the direct countercurrent flow, with at least a portion of the Gas product with a considerable part of the sensible heat of this gas above the temperature of the Carbon source is harnessed. All fleeting ι "> Components such as water, light hydrocarbons and even some coal tar products are volatilized and separated from the carbon source in this preheat stage. This is a in those cases particular preference in which the carbon source Jo contains a significant amount of such materials, as for example in the case of coal.

In addition, any zinc present in the gas and used to contact the carbon source can be recovered by condensation of this zinc on the particles of the carbon source. This advantage is very important because molten zinc has a significant vapor pressure at temperatures far below its boiling point of 907 ⁰ C. For example, at 730 ° C Hegt the vapor pressure of zinc mm even at jo about 100 Hg.

In a similar embodiment of the invention, the gas containing carbon monoxide and zinc and leaves the gasification zone, divided into two streams and one of these streams is directly with the carbon η brought into contact with the source in the preheating zone. In this embodiment, the gas flow that is in Comes in contact with the carbon source, rich in zinc. The rest of the stream goes to a zinc separation zone introduced, in which the zinc is removed from the gas stream. The low-zinc gas stream is preferred also brought into contact with the carbon source The oxidation of zinc and the indirect Heat exchange takes place as in the already described embodiments of the invention.

In another embodiment of the invention, the gas stream is the carbon monoxide and zinc contains and comes from the gas zone, passed through a zinc separation zone in which the majority of the

Preferred operating conditions

Zinc is separated from this gas stream, for example by condensation. The received low-zinc The gas stream is then brought into contact with the carbon source, creating a gas stream that is a Contains zinc-free carbon monoxide. Zinc is condensed on the carbon source.

The zinc from the zinc separation zone can be introduced as such into the HiO oxidation zone, where the Zinc in contact with the carbon source and in The presence of steam is converted to zinc oxide and hydrogen. Some of the zinc turns into zinc oxide in a zinc combustion zone by contacting the zinc with a gas. that contains free oxygen like Air, converted.

The thermal energy of this zinc combustion zone is used to generate at least part of the consumed in the endothermic gasification reaction between the carbon source and the zinc oxide To deliver heat.

It is advantageous to condense as much zinc as possible on the solids feed. In practice, however, this amount is limited by the heat balance and the desired operating temperature in the zinc oxidation zone. The maximum amount of zinc that can be introduced into this zinc oxidation zone is limited by the stoichiometric amount that can be oxidized by the water vapor. Zinc oxide deposited on the solid starting materials through condensation is in a very finely divided state and very uniformly distributed over the surface of the solids. The subsequent conversion of zinc oxide and carbon to carbon monoxide and zinc is very effective as a result.

This modification of the invention employs the use of indirect heat exchangers Minimum and reduces the size of the zinc separation zones. This will reduce the cost of such Plant reduced, while at the same time the thermal efficiency of the process is increased. Part or the entire water vapor can be generated by heat exchange with the gasification outlet. In Depending on the operating conditions, a fraction of the carbon source can already be in the H2O zinc oxidation zone to be gassed. However, this is not detrimental to the method, since that is in this section The gas produced by the process has essentially the same composition as the desired gas.

The temperature and pressure conditions in the three zones are preferably as follows:

temperature Reference number in C. Fig. 9-10 Preheating zone: Temperature of the raw materials Ambient temp. 200 Preheating zone 150-970 201 H ₂ O oxidation zone 500-1200 205 Carburetor zone 900-1650 209 O ₂ -Zn combustion zone 1200-1800 217 Dwell time Preheating zone 1-30 min. 201 H ₂ O oxidation zone 2-30 min. 205 Carburetor zone 10 min-2 hours 209 Oi-Zn combustion zone 0.1-10 sec. ' 217

In order to move the materials used in the process through the various zones, the Touches and conversions expediently at a slightly higher pressure than atmospheric Pressure carried out. If desired, the reactions can also be carried out at higher pressures so that even under high pressure carbon monoxide can be obtained as a reaction product can. The preferred operating pressure is in the range from 101 to 401 kPa.

The beds for preheating, steam oxidation of zinc, gasification and zinc combustion can be moving or stirred beds. The preheat bed is preferred as a moving bed operated to achieve particularly efficient recovery of heat and zinc in this bed. If the preheating zone, the zinc oxidation zone and the gasification zone operated in different vessels the gasification zone is preferably operated as a fluidized bed. In this In this case, the zinc oxidation zone is also preferably operated as a fluidized bed.

As in Fig. 9, a carbon source such as coal or charred material is provided by the Line 200 is fed to a preheater 201. In the preheater 201, the carbon source is im Brought countercurrent to a gas stream from line 202 in contact. This gas stream consists of a gas. which contains carbon monoxide and hydrogen, but also zinc. The zinc gets on the particles condenses from the carbon source and these particles containing some zinc are removed from the preheater 201 removed via line 203. It becomes a product gas stream that is free of zinc from the Preheater 201 withdrawn via line 204.

The zinc-containing carbon particles are introduced into the zinc oxidation zone 205 via line 203. In the zinc oxidation zone 205, water vapor is introduced via line 206. Zinc gets into this zone via the Line 207 introduced. In zone 205, the zinc present on the carbon source is mixed with water vapor implemented, with zinc oxide in finely divided form on the carbon source and hydrogen. Of the Hydrogen leaves the zinc oxidation zone via line 202. The carbon source is along with conveyed the zinc oxide from the zinc oxidation zone 205 via the line 208 into the gasification zone 209. In In this gasification zone, the carbon source and the zinc oxide are converted, whereby a gaseous A mixture is formed which contains carbon monoxide and zinc and leaves the carburetor 209 via line 210. That used as oxygen parts in this reaction Zinc oxide is partly in line 208 from zinc oxidizer 205 and partly in line 211 introduced. The ash is removed from gasification section 209 via line 245

The gaseous mixture containing carbon monoxide and zinc is passed via line 210 to a cooler 212 and a zinc separator 213. In this zinc separator 213, zinc is routed via the line 214 discharged A portion of the zinc removed via line 214 is fed into the zinc oxidizer via the Line 207. Another part of the zinc is introduced via line 215 along with air via the Line 216 introduced into a zinc combustion unit 217. In this zinc combustion unit 217 Zinc and air are converted into zinc oxide and a gas that consists essentially of nitrogen Zinc combustion zone 217 is placed in the interior of the gasification zone in indirect heat exchange. The zinc oxide suspension is fed via line 218 to a zinc oxide separator 219, such as a cyclone ■ 3 or a filter. The solid zinc oxide is removed from the separator 219 via line 211 and in the carburetor, as already explained, introduced. From the separator 219 is a line 220 zinc oxide-free exhaust gas discharged, which essentially consists of

ίο Nitrogen. Carbon monoxide gas that only Contains a small amount of zinc is discharged from the zinc separator 213 via the line 221. This gas is introduced into the zinc oxidizer where some of the zinc is oxidized to zinc oxide. A small part of the zinc remains in the gas stream 202 and is deposited on the carbon source in the preheater 20! condensed. Alternatively, a portion of the gas in line 210, which contains carbon monoxide and zinc, be fed directly into the zinc oxidizer. The amount

2n of this gas is controlled by a valve 222.

Another embodiment of this invention is shown schematically in the flow diagram of FIG explained. From a coal container 10, coal is introduced into the preheater 201 via the line 200. the end this preheater 201 is a gaseous product that contains zinc-free carbon monoxide and hydrogen, Discharged via line 204. A product gas stream containing a small amount of zinc is im Introduced countercurrent through line 202 'into preheat zone 201. The coal particles remove the zinc from this stream. These coal particles contain zinc condensed thereon and become via the line 203 to a vessel 230, in which both the zinc oxidation zone 205 and the gasification zone 209 are arranged. From this vessel 230 a stream containing zinc, carbon monoxide and hydrogen is passed over line 231 withdrawn and through two indirect heat exchangers 232 and 232 'to a zinc separator 233 out part of this flow can be carried out directly via the line 202 ', controlled by the valve 234, go to the preheater 201. Generally, from 0 to about 25% of the current passing through the Zinc oxidizer leaves and contains zinc, carbon monoxide and hydrogen via line 202 'dem Preheater supplied The carbon monoxide-containing gas stream, which is poor in zinc, goes from the zinc separator into the preheater 201 via line 202. Zinc is withdrawn from the zinc separator via line 235. The reheated zinc exiting heat exchanger 232 is in part via line 236 in FIG the zinc oxidation zone 205 is introduced where this zinc reacts with water vapor with the water vapor in the vessel 230 from a water or water vapor source 20 via line 237 through the heat exchanger 232 'and partly via the line 238 in a mixture with air. The air goes out from an air source 55a via line 239 to a zinc burning zone 217 The zinc burning zone 217 is in indirect heat exchange with carbon monoxide and zinc oxide and provides the thermal energy that is consumed during the endothermic gasification reaction. A zinc oxide suspension is discharged from the zinc combustion zone 217 via line 240. Zinc oxide is produced therefrom The suspension is separated in the separating device 241 and returned to the gasification zone via the line 242 introduced as in detail in connection with FIG. 9 was explained.

A gas which essentially contains nitrogen is discharged via line 243.

The following table shows flow rates in kgMol per hour for a case in which a 100% conversion of the carbon source, input and output of all raw materials and all products

at 25 ° C and an operating temperature in a gasification reactor of 1137 ° C at a pressure of 1 up to 4 atmospheres are assumed. The following table shows the material balance for these materials. The numbers in brackets relate to FIG. 6.

Tabel

Carbon (31) Water (130) Air (125) Oxidpro- Zinc (121)

products (120)

Hydrogen nitrogen (131) (129)

Carbon (C) 6.36 Hydrogen (H) 0.80 Nitrogen (N) 0.04 Sulfur (S) 0.11 Oxygen (O ₂ ) STICKS (N ₂ ) CO CO ₂ NO SO ₂ Zn ash 0.18 water Hydrogen (H ₂ ) Together 7.49

1.91
7.22

3.45 7.22

6.12
0.24
0.04
0.11

0.40

7.27

3.45

3.45

9.13 6.91

7.27

3.45

7.22

If an overall efficiency of only 70% is assumed to prevent heat leaks, losses when Taking into account heat exchange and the like, the feed rates would be 1.13 kgmol Water per hour and 3.07 kgmol oxygen per hour.

The 7.27 kgmoles of zinc circulating in the system in the case of 100% conversion under the above conditions were split into 3.45 kgmoles in line 124 and 3.82 kgmoles in line 123. Accordingly, with a 70% conversion In terms of efficiency of the process, 7.27 kgmoles of zinc circulating in the system are broken down into 1.13 kgmoles in line 124 and 6.14 kgmoles in line 123.

In addition 9 sheets of drawings

130 215/385

Claims (1)

Patent claims: 1. Process for the production of carbon monoxide, in which one a) converts a solid carbon source in a reaction zone at a temperature range of 910 to \ 540 ° C with zinc oxide to zinc and carbon monoxide, b) separating zinc from the gas and isolating the carbon monoxide,