DEP0004334DA - Method and device for the gasification of solid fuels with the gradual addition of the gasification agent - Google Patents

Description

Kr ₀ 228

'.es η tr λ tn rn

, August 4, 1948

Frankfurt (Main)

Method and device for gasification of solid fuels under gradual? Addition of the gasification agent

The gasification of solid fuels by an oxidizing gasification agent as z ₀ B _4, air or oxygen or a mixture of both in the mixture with water vapor represents} yields due to the exothermic heat of reaction in the reaction of free oxygen at a high temperature in the combustion and gasification zone _o height of the temperature is determined in the main by the concentration at which the oxygen in the gasification agent ^ "new other factors such rwärmung ₀ B ₀ V © of the gasification agent," and the fuel, heat losses O ₀ like ο Depending dem'Erweichungs - and the melting point of the ashes of the fuel, sintering, softening, melting or liquefying of the ashes can occur in the combustion zone of the gas generator “If the ashes are discharged in the solid state, they can only be sintered slightly t or be slightly melted together in individual pieces so that the difficulties during discharge do not become too great »The concentration of free oxygen in the gasifying agent must therefore not exceed a certain upper limit are, if necessary supported by the preheating of the gasification agent, that the ash melts well and the melt flow is maintained until the. Slag is tapped »

If a fuel with a low ash expansion point is to be gasified in a gas generator with discharge of solid ash, the concentration of oxygen must be kept low, which has the disadvantage that the efficiency of the gasification drops sharply and a gasification gas of low quality with an often undesirable composition is obtained _o When lean gas is generated by an air-water vapor mixture, the dew

Ur ₀ 228

METALLGESELLSCHAi ¹ T

Corporation

Frankfurt (Main)

point of the gasifying agent is kept between 50 and 60 ° 0, which corresponds to oxygen content between 16.8 and 18.4 ° /> in the gasifying agent 75 °. G, to be set, according to oxygen kept between 12.7 and 14 _S .3 f ° in the gasifying agent »Hereby the gasification _{efficiency falls from z o} B ₀ 82 $ to l & fo and the upper calorific value of the generated gas of Z ₀ B ₀ 1300 1150 thermal units per gas only (based on 0 ° 0 and 760 mm QS) O

In the production of nitrogen-poor gases, ζ «B, of hydrogen and carbon-oxide-rich gases for synthesis purposes, through the gasification with oxygen-water vapor mixtures, a low concentration of oxygen in the gasification agent has an effect mainly through an increased consumption of oxygen,? / asserdampf and carbon from "If the consumption figures in the gasification with a mixture of 18 vol. fo oxygen and 82 vol. fo steam, z _{o 0} B at

0.22 Nm ⁵ oxygen per Nm ⁵ H ₂ + 00 0.81 kg V / water vapor "» "

0.39 kg carbon "*"

so the consumption figures with a mixture of 13 vol. fo oxygen and 87 vol. fo water vapor as a gasifying agent increase to about the assumption that the gasification conditions are otherwise the same

0.27 Wm ³ oxygen per km ⁵ Hp + 00 1.40 kg water vapor "» 0.41 kg leg charcoal ""

In addition, the content of carbonic acid in the gas generated increases, which increases the cost of. Removal of carbonic acid from the gas increased, Audi shifts the volume ratio of hydrogen to carbon oxide in the gas produced from eg "B ₀ 1.4 to 2.4, which Z ₀ B ₀ is unfavorable for many synthesis purposes *

If the gasification is operated under increased pressure, the combustion and also the gasification processes run much faster, so that in the combustion zone of the gas generator the temperatures would rise considerably and the ash would melt, would not

228

MB TALLGESELIiSOHAPT

Corporation

Frankfurt (Main)

the oxygen content in the gasification agent can be reduced even more. «Experience has shown that with the usual fuels and a gasification _{pressure of, for example,“ B 0} 20 atmospheres, the material content must be 7.5 to 12.5% by volume ”. fö can be reduced in the gasification agent / bainite ash difficulties are avoided

The method according to the invention eliminates the disadvantages of gasification with low oxygen concentrations in the gasification agent and also gasifies fuels with low ash softening points in the end result with high oxygen concentrations of the gasification agent, so that the most favorable operating conditions in terms of lowest consumption figures and certain composition of the gas generated, especially in the With regard to a certain volume ratio of hydrogen to carbon oxide, the process according to the invention provides for a gradual addition of gasifying agent, whereby in the first stage, as usual, a gasifying agent with such a low concentration of oxygen is introduced into the gas generator, that there are no ash problems due to sintering or melting. After the gasification in the first stage, the gasification gas, which is advantageously not cooled, is given as much oxygen} oxygen-enriched air or air mixed so that the gasification gas is heated by partial combustion to a temperature that is still permissible to avoid ash clouds. This heated gasification gas is used as a reducing gasification agent in the fuel bed of the second stage and gasifies a further part of the carbon. After the gasification reactions and the associated lowering of the temperature of the gas have subsided, the gas can be _{heated in a third and, if necessary, in further stages again by admixing oxygen}} oxygen-enriched air or air with partial combustion and passed through the fuel bed of these further stages »In all stages except the First of all, oxygen, oxygen-enriched air or air is concentrated in the gas without the addition of water vapor

No 228

METALLGS SELLSOIiAi ¹ T

Corporation

Prankfurt (Main)

the exact dosage of the combustion agent prevents water vapor or carbonic acid or the like can be added to the connective agent in such quantities as the durability of the building materials, especially the supply ducts of the combustion agent, requires of water vapor ο. etc. _o minimum to aalten! dadurGh as the intended effect of gradual. Gasification is partially or completely canceled by increasing the oxygen concentration of the gasification medium or more stages than otherwise necessary must be provided ₀

By the method of the step-by-step gasification according to the invention it is achieved that even when a fuel is present low ash softening point or in the case of gasification under higher pressure, the gasification agent in its entirety may have a high concentration of oxygen, ο tine that it leads to sintering or melting of the ashes and damii to a There is a risk to operational safety. This increases the gasification efficiency improves, the specific consumption of oxygen, water vapor and carbon is also reduced and a Gas with a higher calorific value and a lower ratio of hydrogen to carbon oxide obtained "

Samples T brown coal coke is gasified at 20 ATII with a mixture of 7> 5 Voio fo oxygen and 92.5 vol. $ Water vapor, wherein just the ash sinters easily, so that no difficulties occur even in the removal of ash. Under suitable gasification conditions with regard to preheating of the gasification agent and the fuel, heat losses during gasification, reactivity of the fuel, fuel bed height and so on, a gas of the following composition is produced;

Yiasserstoff: 7.7 i Vol.

Carbon Oxide: 0.9 "

Carbon dioxide: 10.5 "

Water vapor: 80.9 "

with a consumption of

0.83 Nm ⁵ oxygen per Im ³ H ₂ + CO 8.3 kg water vapor " ^l9 0.71" Eeinkohle ""

No. ₀ 228

METAL GE SBLL SC BJLP T

Corporation

Frankfurt (Main)

The gas composition is therefore very unfavorable, the consumption figures are very high. Is admixed to the present invention without cooling this gas in the second stage so much oxygen that Sigh _0, 300 ° heated by partial combustion by Z, which is just possible without exceeding the Sinterungsgrenze the ash, so for this purpose are about 0.027 only oxygen per NIRR gasifying agent the first stage required hereby increases by adding the gasification agent of the first two stages of the oxygen content of the gasifying agent auif 9.9 VoI $ _0. If the heated gas is passed through the fuel bed of the second stage, a gas with the following composition is produced:

19.7% of hydrogen - 1 ° of carbon oxide! 5.1 "

Carbonate 16.1 "

Water vapor 59 _s l "

with a total consumption of

35

00.

Oxygen per Mel ⁵ H + 2.6 kg, water vapor "" 0.46 kg pure coal ⁿ »

The composition of the gas and the consumption figures improved considerably through the second stage. *,

If, according to the invention, so much oxygen is again mixed in with this gas in a third stage that it sieves, through partial combustion

o '3

tion heated by 300, this requires about 0.030 Nm of oxygen • z

depending Nm gasification agent of the first stage requires "a result herewith the oxygen content increases the total supplied gasifying agent to 12.5 by volume $ _9. When the heated gas is passed through the fuel bed of the third stage, the following gas is produced

Hydrogen! 26 _? 9 "VoI #

Carbon oxide; '10.4 ^M.

Carbonic acid 18.4- "

Water vapor 44 _s 3 "

with a total consumption of

0.27 Nm ⁵ oxygen per Fm ³ H ₂ + 00 1.54 kg water vapor "" 0.41 kg pure carbon ⁿ "

228

Share-tight rope team
Frankfurt (Main)

In a fourth stage, only about 0.032 oxygen are necessary, 'whereby a result of the oxygen content to 15.0 VoI ₀ fo the total supplied gasifying agent boosted The produced gas has the composition!

Hydrogen 31.1 vol. ₀ fo

Carbon dioxide 16 _s 3 "

Carbonic acid? 18.8 "

Water vapor 33.8 ^H

with a total consumption of approx

0.24 Nm ³ oxygen each. Nm ³ H ₂ + GO 1.10 kg water vapor "" 0.40 kg pure coal ^{π π}

The following figures result for a fifth level: Oxygen consumption 0.035

Oxygen content

resulting for that

whole gasifying agent 17, VoI 7 «i °

generated gasi

Hydrogen 33.3 vol,

Carbon dioxide! 22.3 "

Carbonate 18.1 "

Water vapor 26.3 "

with a total consumption of

0.23 Nm ³ oxygen per Um ⁵ H ₂ + CO 0.86 kg water vapor "" 0.39 kg pure carbon » ^M

In this example, the gasification was conducted in such a way that there was no significant methane formation, so that methane formation did not have to be taken into account in the figures In the end, a gasification agent with a high oxygen content can be created. ₀ This improves the composition of the gas generated and the consumption figures drop

No. ο 228

METAL GBSELLSOFT

Corporation

Frankfurt (Main)

substance content, so that it is often advantageous to work with only three to five stages. ”Also noteworthy is the change in the volume ratio of hydrogen to. Carbon oxide in the gas produced, which z _o B ₀ drops from 8 _S 6 to 1.5, the exact setting of which to a certain value is important for some syntheses »This ratio could be reduced even further by further steps»

The proportion of hydrogen in the gas also increases with the individual stages. Since methane formation depends on the level of the partial hydrogen pressures in the gas, along with other factors, the method according to the invention can also lead to an increase in methane formation in the individual stages result, when the methane reaction is z "B _o given by appropriate dimensioning of the fuel layer heights sufficient time * hereby also the calorific value increases of the resulting gas, so that the process of the gradual gasification of the invention can be used with advantage in accordance with, high a gas heating value , Z ₀ B ₀ for town gas purposes, by pressurized gasification using oxygen and water -. To be generated as gasifying agents »I ¹ Only a few stages are normally required for this purpose? 15 VoI ₀ i » lies"

The admixing of the oxygen, the oxygen-enriched air © or the air to the gas and the partial combustion of the gas are advantageously carried out under roofs that are arranged in the fuel bed. These roofs consist of side walls that are sloping can be arranged to one another or in parallel and over which hoods are provided at intervals so that the gas flowing up in the fuel bed preferably flows up through the roofs and back under the hoods into the ' Bulk fuel escapes »At the same time, the hoods prevent the fuel from above into the roofs formed spaces get kamu The roofs can be completely or partially made of ceramic material or steel 0. The like »exist» They become advantageous with round shafts

# 228

IWETALLGE SELLSCHAi ¹ T

Corporation

Prankfurt (Grove)

Arranged in a ring, in the case of angular shafts it is advisable to lay them parallel to each other _o The roofs of the individual steps should always be offset from those below and above. Roofs should be arranged in order to achieve a certain cross flow of the gases through the fuel bed. It is advantageous to use fireclay bricks as building materials, which are supported by cooled steel pipes ₈ with the steel pipes as feed lines. for the combustion agent - oxygen, oxygen-enriched air or air - can be used »With certain fuels, it is sufficient to put cooled steel pipes as a feed line for the combustion agent through the fuel bed without any further roofing in order to ensure that the gas is heated up sufficiently evenly Achieve »Y / ater, steam, air, but also the supplied combustion agent itself, can serve as cooling for the pipes *

Various embodiments of the step-by-step gasification show, for example and schematically, Figures 1 - 3 ° In Figure 1, a round shaft gas generator is shown, 1 is the Schaalit jacket, 2 is the discharge device for the gasification residues, 3 and 4 are the roofs or similar fixtures for the supply of gasification agent of the second and third stage ₀ The gasification agent of the first lowest stage is passed with a low concentration of oxygen, Z ₀ B ₀ through the hollow shaft 5 of the discharge device 2 _{ under the grate and -distributed over the whole shaft cross-section » After its conversion to the fuel, the gas flows through the gas spaces 6 of the internals 3 and is advantageously heated to a temperature just below the softening point of the ash _{by adding gasifying agent Z 0} B _{0 more concentrated in oxygen through water-cooled feed pipes 7 and partial combustion} built ring-shaped in the round shaft » They consist, for example _, of firebricks, which are carried through water-cooled pipes 8 and, if necessary, through the supply pipes 7. made of fireclay bricks, which allow the gas to flow out unhindered, but which do not allow the fuel to penetrate into the gas chambers «. The heated gas flows out from under the roof hoods 9 into the second gasification stage 10 and gasifies further fuel, whereby its temperature en * t-

# 228

METALLG-ESELLSOHAi ¹ T

Corporation

Prankfurt (Main)

In terms of the endothermic gasification reductions _{, it} then passes through the internals 4> which are constructed in a similar way to the internals 3, but offset from them, is reheated and gasified by adding more concentrated gasification agent from the water-cooled pipes 11 with partial combustion in the third stage 12 additional fuels Depending on the need, the third stage can be followed by further stages «

Figure 2 shows a square Sehacht gas tiger with two rows 13 and 14 of four internals lying parallel to each other, in order to combine the gas from the fuel layer and in the free tree 15 of the internals by adding gasifying agent more concentrated in oxygen through the distribution pipes 16 and partial combustion to be reheated _ö The discharge device for the ash and the first lower gasification stage are not shown, furthermore all further details which, as known per se, can be omitted in the drawing *,

Figure 5 shows a simplified embodiment of the new stage gasification, as it can be used advantageously with small-grain fuels »17 shows the round or angular shaft casing of the gas generator, in which the loading device, discharge device and the supply of the gasification agent of the first gasification stage have also been omitted 18 of the untersten'Reihe are water-cooled feed pipes ₀ the gasification agent is for the concentrated oxygen gasifying agent of the second stage, zweGkmässig blown downward or laterally in the fuel layer and mingles with Tei! combustion of the gas

and partial combustion of the fuel so that the gas serves as a reducing gasifying agent of the second stage 19 can «, after the second stage is, advantageously arranged offset? a second row 20 for feeding the Gasification agent for the third stage 21 «Due to the gasification agent supplied, the gas is again under partial combustion heated »Depending on requirements, additional rows of tubes can be arranged for additional stages * The tubes of each row of tubes

No. ₀ 228

MEIALlGESELLSCBAi ¹ I.

Joint stock company

Prankfurt (Main)

are advantageously put together closely _? z »B. ' to a clear "distance of 50-100 mm, in order to enable sufficient and rapid mixing of the newly supplied gasification agent with the gas o

Considerably simpler to carry out the gradual gasification according to the invention with pulverized fuels in the floating state, the supply of the oxidizer to heat the gas in the individual stages can in this case by a simple injection of the combustion agent into the dust "laden gas which normally a free of internals The step-by-step supply of gasifying agent in the gasification of pulverulent fuels in suspension is known, however, in the stages following the first stage, no concentrated combustion air was used and the effect of a gasifying agent was not achieved resulting in a higher concentration of oxygen with the stages «

Claims (1)

No. ₀ 228 ICETAILGESELLSOHAPT Corporation Prankfurt (Main) Claims t ' 1 ») Process for the gradual gasification of solid fuels aaduro.ii characterized that in the first stage the amount the oxygen content of the gasification agent is chosen so low that the ash behaves benign, and that in further stages so much more oxygen concentrated gasifying agent the hot, advantageously not cooled down Gasification gas is admixed with partial combustion of the gasification gas, as allowed by the AsGhe behavior of the fuel, and that the heated gasification gas is used as a reducing gasification agent © in the fuel bed of following stage is used. 2ό) Method according to claim 1 dado gek * that, -as many stages are used as are necessary to produce a gas with a to generate a low ratio of the amounts of hydrogen to carbon dioxide 3 «) Method according to claim 1 dad» gek ₀ , that as many stages are used as are necessary to generate a gas with the highest possible calorific value «, 4 ») Device for carrying out the method according to claims 1-3, characterized by channels, narrow chambers Oodgl» in the gas generator, which are open at the bottom and covered by hoods at the top, through which the generated gas preferably flows, and duroh distribution devices in the channels Oodgl ₀ for the supply of gasifying agents that are more concentrated in oxygen 5.) Device according to claim 4 da.d _o gek. That the distribution devices consist of steel pipes which are equipped with a jacket for the passage of a coolant and evenly spaced with slots or holes for the uniform admixture of the oxygen-concentrated gasification agent to the gasification gas are provided _o 6 «) device according to claim 4 and 5 dado gek _e that the. cooled distribution devices as a support element for the channels o "like _o No. ₀ 228 METAIiLGESELLSOHAi ¹ T Corporation ! Frankfurt (Main) serve, where the coolant, Z ₀ B ₄ water, if necessary with steam generation, steam, air or the gasifying agent itself is used » Apparatus according to claim 4-6 dad _a gek ₀ that the channels or the like _o each stage offset to the channels below or above it ο ο the like _{D of} the neighboring stages 8o) device naoh claim 4-7, dad. .geko that the channels ο β like "are ring-shaped in the case of round gas generators".