DE2814216C3 - Process for the production of gases containing hydrogen and carbon oxide - Google Patents

Description

A number of methods for gasifying fossil fuels by partial oxidation have been described. These processes are generally such that the fossil fuel is fed to the gasification zone in gaseous, liquid, suspended or solid form and is gasified there with oxygen or oxygen-containing gases with the addition of water. Here vm-Λ the heat necessary for gasification is applied through the partial oxidation of the fossil fuel. The water added to the gasification has to fulfill two tasks, on the one hand to keep the reaction temperature occurring within limits zj, but on the other hand also in accordance with the water-gas equilibrium

C + H ₂ O ^ CO-IH ₂

to actively participate in the gassing. This water can be either in vapor form or in liquid form Reaction zone are fed. The amount of water added varies between 0.15 and 0.5 t per t of oil.

The partial oxidation is usually used for that Production of carbon-oxide-rich gases with a low calorific value or the gasification of such materials used, which are not suitable for gasification by the steam reforming process.

Materials suitable for gasification are all hydrocarbon compounds; However, it is preferred to use non-volatile hydrocarbons, residual oils, crude oils and coal, but also those which contain hydrocarbon compounds and which can be obtained from household waste or plastic residues.

With partial oxidation, some of the carbon used is not gasified, but falls together with the cracked gas and the unreacted water as soot. This soot must be separated and fed to a use, preferably naturally fed back into the process.

A whole series of processes has been described to separate this soot from the cracked gas and the To supply gassing again. All of these methods require considerable effort. A well-known one Soot treatment process is shown in Fig. 1

represents; it works according to the following principle:

Heavy fuel oil (2) is partially oxidized with oxygen (3) with the addition of steam (1) in the generator (4) The cracked gas generated in the process gives off in the waste heat boiler (5) its heat and arrives via line (6) in the Soot washer (7), where it is washed with water, then via line (8) for further processing to be fed. The soot-containing washing water (9) is mixed with gasoline (10); the mixture will be in

ίο a separating vessel (11) separated into water and petrol, most of the soot going into the senzin phase. The soot-containing gasoline (12) is fueled with heating oil (13) mixed and then transferred to a fractionation column (14) in which most of the gasoline

is recovered. The soot-containing oil (15) obtained in the bottom of the column is subject to partial oxidation fed. The water (16) largely freed from soot is removed from the column (17) by stripping released gasoline and pumped (18) into the

Recirculated soot washing column

It has now been shown, surprisingly, that in the Presence of sufficient amounts of metals and / or metal compounds in the gasification, only very little or no soot at all is produced. Through this is it possible to use an additional soot treatment, such as it is necessary for the processes according to the state of the art to be dispensed with entirely.

In DE-AS 1170 379 a method described that damage to the generator wall

.w work through the natural ones contained in the oil Heavy metals SHOULD prevent. As a suitable measure, it is suggested to prevent the reaction taking place To direct variation of the amount of water added so that the reaction is always 50 to 100 times too much free carbon is formed as it is the amount of corresponds to heavy metals contained in the feedstock.

It has now been found, surprisingly, that in the Presence of higher concentrations Schwermeiallen and heblichen Vermin- characterized ft

No damage to the generator masonry can be observed due to the change in the carbon produced during the reaction, if during the production of carbon oxide and gases containing hydrogen by partial oxidation of fossil fuels by means of oxygen or Oxygen-containing gases with the addition of water, subsequent water scrubbing of the crude gas and recycling of metal compounds containing Wash water, the water fed into the gasification zone between 0.1 and 2% by weight of mixtures of

Alkali and alkaline earth metals and metals of the transition elements including the noble metals and / or Metal compounds, with the elements nickel, iron and vanadium being the main components, as a solution or suspension, and this subsequent What scrubbing of the crude gas and recycling of Me wash water containing metal compounds, the water fed into the gasification zone between 0.1 and 2% by weight of mixtures of alkali and alkaline earth metals and metals of the transition elements excluding borrowed the precious metals and / or metal compounds, the elements nickel, iron and vanadium being the The main components are, as a solution or suspension, and this concentration by recirculation the ash and soot-containing scrubbing water of the raw gas laundry is set for gasification.

A special embodiment is that to maintain the metal concentration in the gasification water this aqueous solutions and / or

Suspensions of metals or metal compounds are added.

The alkali and alkaline earth metals and the metals of the transition elements, including, have proven to be suitable of precious metals proved. Mixtures of these elements are used, with the main components such mixtures should be the elements nickel, iron and vanadium. The metals can be in suspended or dissolved form can be used. Both pure metals can be used as well as their connections.

Metal concentrations in the range from 0.1 to 2% by weight, based on that of the, have proven to be effective Water added to gasification has been proven. This concentration can be caused by the discharge of a certain Part of the metal-containing wash water can be kept constant or changed.

A preferred embodiment of the method according to the invention will be based on the attached Drawing and an example are explained in more detail.

The drawing and the examples relate to a procedure in which heavy fuel oil is used as Feedstock is used and the cracked gas is cooled in a waste heat system.

Explanation of the procedure on the basis of the attached Fig.Z

Via pump (1) and line (2) a mixture of water and oil and through line (3) oxygen is the Generator (4) supplied.

After the gasification reaction, the cracked gas leaves the generator (4) and passes through the waste heat system (5) through line (6) into the lower immersion of the wash column (7). There is the one in the gassing Any resulting soot and all of the ash carried along are absorbed in the water present there.

The cracked gas reaches the second dip of the scrubbing column via line (8) and is still washed twice before it is completely freed from ash and soot particles the system through the line (9) leaves to be processed further.

The wash water of the 2nd dip is drawn off at their sump through line (10) and via a Pump (11) distributed over two shower heads (12 + 13), whereby the washing water that flows into the upper shower head (12) arrives, is additionally cooled

The amount of water that is added to the lower immersion via line (15) is added via line (14) is fed.

The amount of water that reaches the lower immersion through line (15) fulfills two tasks. Once the water level of the lower immersion is supplemented and possibly with the gas in the upper immersion Ashes and soot that arrive are transported downwards so that there is no accumulation in the upper immersion can be done.

The ash and possibly soot particles containing ίο water of the lower immersion is in their sump withdrawn and with the help of a metering pump (16) in the desired amount through line (17) the feed oil supplied, with which it reaches the generator together through line (2).

Through line (18), part of the ash-containing water can be discharged to a set the desired concentration of ash components.

If necessary, a metal-containing solution and / or suspension can be added to the ash water through line (19) are added.

The Fig.2 shows what considerable Simplification of the equipment is made possible by the method of operation according to the invention.

Example !

In a technical system that after the The process explained in the drawing works, a comparative test was carried out.

First, the gasification was operated with fully desalinated water. That in the wash column Any water containing soot and ash was fed to a soot treatment plant

The method according to the invention was used in the comparative experiment

After a previous ash accumulation, the soot produced during the gasification was removed absorbed in just such an amount of water as is necessary for the gasification

A heavy fuel oil with the following nominal sizes was used for gasification

C: 863%, H: ll, 8%, S: 1.70A _> O <0.4%, N: 0.36%
Hu: 41,090 J / g, Ho: 43,660 J / g

The test results can be found in the following table.

Attempt 1 Attempt 2 VE water metalliferous
Soot water Oil t / h 10 10 O ₁ NmVh 8850 8850 H ₂ O r / h 3 3 TReak. ⁰ C measured 1368 1370 Removal from the swamp
the soot washing column i / h
Kiss concentration in the 7.2
for soot treatment
2.86 3
to the generator
0.27 discharged water,% by weight Soot incidence kg / h 206 8th Ash concentration in
discharged soot water 0.001 0.26

continuation

Attempt I. Attempt 2 Vü-W; ivscr metalliferous KuUwusscr Main components of the returned ash: Al: 0.4 wt% Na: 0.7% by weight Fe: 6.2 wt% Ni: U, 3% by weight V: 34.3% by weight Cracked gas analysis: CO, 5.6 5.8 CO 46.8 46.1 H ₂ 46.7 47.2 Inert 0.3 0.3 CH ₄ 0.2 0.2 H ₂ S 0.4 0.4

The process according to the invention works particularly economically because it is carried out simultaneously with the washed-out Ash of all soot resulting from the implementation is returned to the gasification. This simultaneous Return of the accumulating soot for gasification without additional soot processing is only possible if the amount of soot produced is low.

Suspensions of soot in water with a solids content of up to 3% by weight can be pumped be funded without additional measures. From a concentration of 3% by weight, the suspension is Can only be funded through the addition of flow aids. With a carbon content > 6 wt .-% the suspension is already so viscous that it with Pumps can no longer be promoted.

Be ^: the previously common gasification with the addition of steam or liquid water produces so much soot that the amount of water in which the carbon is absorbed

jo must be in order to be an eligible suspension too received, is much greater,?! s the amount of water that is required for gasification or is economically justifiable. In the presence of effective metals and / or metal compounds in gasification is the Soot concentration so low that there are no flow problems with the suspension. The amount of water in which the Soot and the catalytically active ash are collected, the water requirements of the gasification

4n can be adjusted.

For this purpose 2 sheets of drawings

Claims (1)

Claim: Process for the production of gases containing carbon oxide and hydrogen by partial oxidation of fossil fuels by means of oxygen or Oxygen-containing gases with the addition of water, subsequent water scrubbing of the crude gas and recycling of washing water containing metal compounds, characterized in that the water fed into the gasification zone contains between 0.1 and 2% by weight of mixtures of alkali and alkaline earth metals and metals of the transition elements including the Noble metals and / or metal compounds, the elements nickel, iron and vanadium being the The main components are contained as a solution or suspension, and this concentration is achieved by recycling the washing water containing ash and soot the raw gas scrubbing is set for gasification.