CA1062087A - Process and apparatus for heat-treating fuels of organic origin - Google Patents
Process and apparatus for heat-treating fuels of organic originInfo
- Publication number
- CA1062087A CA1062087A CA274,628A CA274628A CA1062087A CA 1062087 A CA1062087 A CA 1062087A CA 274628 A CA274628 A CA 274628A CA 1062087 A CA1062087 A CA 1062087A
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- gas
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Abstract
Abstract of the Disclosure A deposition of tars in heat exchangers, exhaust gas conduits and chimneys in conjunction with the thermal utilization of fuels of organic origin and of combustible waste material (straw, waste wood) is prevented in that the combustible material is permitted to move under the action of gravity and is then deflected to an approximately horizontal direction and while moving in the latter direction is degassed and incompletely burnt with cracking of the previously formed hydrocarbons. The resulting gas fractions are throttled, agitated, mixed, collected and transformed into a gas stream, which is supplied to gas burner together with at least that quantity of oxygen that is required for a complete combustion of the combustible matter still contained in the gas stream in an existing or adjusted stoichiometric proportion to the oxygen which has been supplied. The reactor proposed for carrying out this process contains a hollow chamber, which in the direction of gravity succeeds shaftlike fuel containers, and a transverse tube, which extends through the hollow chamber.
Description
~o6Z087 This invention relates to processes and equipment for treating fuels with formation of gases which contain hydrocarbons that have been derived from the fuels and form tarlike condensates when cooled below their dew point.
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To cope with the problems involved in such processes, a number of proposals have already been made with the ob~ect of controlling the process in such a manner that neither during operation nor during inevitable ^-cooling periods which are due to interruptions in operation `
there will be a deposition of tar on heat exchange surfaces which belong to heat exchangers required for purposes of heat economy. A deposition of tar on such heat exchange surfaces would result in a decrease of the thermal efficiency of equipment serving to carry out the process below tolerable values. A basic solution which has also been proposet already is characterized in that the hydrocarbon-containing gases are forced through zone8 which are at very high tem~peratures so that the hydrocarbons are cracked in these zones and can no longer deposit on said heat exchange surfaces as tar layers which would give rise to the above-mentioned dangers because the fluid to be heated, consisting in most cases of water, is usually at room temperature at its initial contact with heat exchange surfaces so that the requirements for condensation are inherently fulfillet.
It has also been found previously that it is inherent in the nature of the above-mentioned fuels that dry distillation may result in an unexpectedly strong development of gas, which can be described as a stream of distilled-off gas, produced by dry distillation, during the time in which the above-mentioned ~he treatment results in higher fuel temperatures and consequently in exothermal reactions. That stream tends to displace the ~06Z087 oxygen~ which is generally supplied as combustion air or -oxygen-enriched air and is required for a regularly effected ,~ -pregasification and at least partial combustion. As a result, pockets of distilled-off gas may be preserved even in the oxidizing zone~ so that tar-containing gases which have not been decomposed leave the oxidizing zone although cracking temperatures occur in said zone. That detrimental phenomenon has been suppressed in that the combustion air was supplied in partial streams along the path which is tefined for the fuel by the equipment for carrying out the process. In this way, the cloud of -distilled-off gas was divided and a formation of pockets of distilled-off gas W8S avoided.
In accordance with a new lnventive recognition the above-mentioned difficulties can be eliminated in a different, atvanced manner. This recognition is based on the fact that the fuels from which the above-mentioned hydrocarbons are derived which tend to form tarlike condensates are malnly surplus products of agriculture, ~`
horticulture and/or forestry and/or their wastes, which have recently been described as residual products. Whereas the first alternative is and will remain an only intermittently occuring special case, which cannot been taken into account in any planning relating to energy economy, the above-mentioned wastes become available regularly and in enormous quantities in con~unction with the provision of food for human beings and animals. So far, the removal of these wastes has adversely affected a desired ecological condition.
For instance, in Germany alone about 25 million metric tons - ` 1062087 :
of grain straw become available per year and the systematic thermal utilization thereof by degassing or dry distillation, gasification and combustion would decrease the required petroleum imports by about 12%. When it is considered that residual products in the form of wood, legumes, dry shrubs and tops etc. become available in quantities which are not smaller and that the same remarks are applicable to waste products from imports, the energy gap can be reduced to an even larger extent. It is of very high significance that a utilization in accordance with the invention can be carried out in an ecologically ~;
satisfactory manner and that the annual aftergrow will prevent an eventual complete exhaustion of the world resources of other energy sources. The above-mentioned energy deficiency cannot be closed by nuclear power.
Until 1985, 4000 metric tons of uranium fuel will be present in Germany alone and will increase by one fourth per year. Within at least ten years, a large-scale plant which is to be erected in the meantime will have to be ;
used to separate iodine 129 by 99% krypton 85 by 90%, and tritium by 75 to 80%; the remainder is to be discarded anyway. In an aqueous solution, 509 grams of plutonium 239 constitute a critical mass which is sufficient for an explosion. In 1985 there will be 30 metric tons of fissionable plutonium in Germany. The element wh~ch emits the high-energy gamma rays is highly toxic chemically and decomposes to one-half only within 24 400 years. Whereas the decomposition can be accelerated by the addition of plutonium to the conventional reactor fuel elements as a fuel, this means . .
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that increasing quantities of the dangerous element must be tolerated in the nuclear reactors and even larger quantities of plutonium-containing materials must be transported. The `
ob~ects which have not yet been satisfactorily accomplished have thus been outlined. The presently contemplated storage `i in abandoned mines, in the abandoned stock-shaped bodies of salt from which potash salts have been recovered, or the submerging in the oceans are makeshift solutions, which are almost ridiculous in view of the above-mentioned ;
"~ ,:
half-value period of thousands of years. ;
These statements confirm the urgency and importance -of the recognitions on which the present invention is based~
which is characterized in that stored fuel which is preerably in the form of lumps, blocks, bales, bundles, sheaves, parcels~ columns~ layers or other compacted sccumulations or in the form of stacked, piled ar otherwise superimposed compacts, high-pressure compacts, pellets etc.
is sub~ected in a treatment chamber to an action of heat which results at least in degassing and/or dry distillation -and, in con~unction with a supply of oxygen, in gasification and in not more than partial combustion, and that resulting gas fractions are mixed and separately from the fuel supply are combined in a gas stream, which is then supplied with oxygen in the quantity which is required for a complete combustion of the combustible matter contained in said gas stream.
The invention which has thus been characterized :f' involves a number of novel technological effects which produce the desired result.
Because the formation of the gas fractions, the mixing thereof and the formation o a stream thereof and the only subsequently effected combustion of the still combustible matter are separated from the fuel supply, the interdependence of the means for supplying fuel and combustion air is eliminated. This interdependence is undesired for the reasons which have been explained hereinbefore. After an air flow region which desirably follows the direction of gravitation, a partial quantity of air or oxygen to be supplied in a first stage may be caused to flow in a second air or oxygen supply phase in a direction which is transverse to the direction of the partial quantlty of air or oxygen in the first phase so ~i that the dlrections of thè alr or oxygen and of the distilled-off gas cross. As a result, any cloud of distilled-off gas which may form ls reliably divided so that a formation of pockets of distilled-off gas is effectively opposed.
A second technological effect which i9 essential for the desired result and is highly advanced resides in that the agitating and/or mixing spaces and the gas steam-forming chambers which succeed the region in which the fuel has been fissured and disintegrated by dry distillation and at least partial gasification can be given that size which is sufficient for a thorough mixing of the gas fractions and for the formation of a decidedly mixed gas stream. A third successful technical effect resides in that the separate formation of the mixed gas stream, on the one hand, and the supply thereto of air , 1062087 ~
or oxygen at least in a partial quantity which is required for a complete combustion of the combustible content of the gas stream~ and generally in a much larger surplus, provide ~ ~
the conditions which are required for the known use of -gas-air burners of a design which results in virtually ldeal flow-dynamical conditions and in the high thermal efficiency which is typical for a complete combustion of a gas.
The nature of the invention may be summarized in that a deposition of tars in heat exchangers, exhaust gas conduits and chimneys in conjunction with the thermal utilization of fuels of organic origin and of combustible waste materials (straw, waste wood) is prevented in that the combustible material is permitted to move under the action of gravity and is then deflected to an approximately horizontal direction and while moving in the latter direction is degassed and incompletely burnt with cracking of the previously formed hydrocarbons. The resulting gas fractions are throttled, agitated, mixed, collected and transformed into a gas stream, which is supplied to a gas burner together with at least that quantity of oxygen that is required for a complete combustion of the combustible matter still contained in the gas stream in an existing or adjusted stoichiometric proportion to the oxygen which has been supplied.
It is inherent in the nature of the invention that is not necessary to mix all gaseous components which appear as fractions. For instance, individual fractions may be separated entirely or partly from other or all 106Z087 ;~
fractions and may be withdrawn and used directly and, if desired~ a remainder which cannot be utilized may -be returned to the agitating~ mixing and gas stream-producing spaces. This remark is applicable~ e.g.~ to the distilled-off gas fraction so that gaseous or vaporous -constituents contained in the distilled-off gas, such as chemicaily valuable pentosans, furfural, low-temperature tar vapor constituents etc., can be separately collected and utilized~ and constituents which are inert under the existing conditions, such as high-temperature nitrogen, carbon monoxide~ carbon dioxide can be returned into the treating equipment so that the heat content of these '-gaseous constituènts can be utilized in one or more heat exchangers.
Special advantages will be afforded if the above-mentioned treating methods are carried out under subatmospheric pressure. Advantages reside in that the equipment for carrying out the process can be sealed more easily, the combustion air can be supplied more easily in several stages, and the degree to which the ~`
gas fractions are mixed can be improved in that the air is supplied into the gas stream by an injector or ejector unless suction or pressure blowers, fans etc.
are preferred.
Whereas the above-mentioned details of the process ensure that each of the heat trea~ments mentioned can be carried out at the highest practicable efficiency, it may be justified in individual cases to supplement the process by a catalytic afterburning, especially because ..
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the process results in particularly favorable space conditions which enable the accommodation of one or more suitable catalysts. The same remarks are applicable to the accommodstion of one or more heat exchangers. It ~ -is particularly possible to provide a second wall, which is parallel to a wall of the treatment chamber and defines a compartment which communicates with and is flown through by gas which leaves the treatment chamber, and to provide one or ~ore heat exchangers, which are accommodated in the `
compartment and consist, e.g., of finned tubes flown through by a heat-absorbing fluid so that exhaust gases which are free from tar~ sulfur, vapor~ and smoke can be discharged into the environment without polluting the latter.
Further details of the process will be mentloned in con~unction with embodlments shown by way of example on s the drawings. `
Equipment which is suitable for carrying out the process is basically characterized in that a fuel storage container assembly is succeeded by a hollow chamber assembly for effecting at least a degassing and gasification and/or dry distillation and not more than a partial combustion and possibly a carbonization and for accommodating a gas burner, -which is preceded by agitating and premixing spaces and/or means, means are provided for collecting and for producing -a gas stream from the gas fractions that have been produced from the fuel and contain distilled-off gases, air gases and combustion gases, and means are provided which open into the hollow chamber assembly and the gas burner assembly and serve to supply air or oxygen.
`` 1062087 The drawing shows illustrative embodiments of equipment for carrying out the process which has been described and details of the process. In the drawing~
Fig. 1 is a transverse sectional view taken on line I-I in Fig. 2 and showing equipment which embodies the invention and serves to produce a gas by a heat treatment of fuels with formation of a gas which contains hydrocarbons that have been derived from the fuel and form tarlike condensates when cooled below their dew point. me `
fuel may consist, e.g., of bales of compressed straw, which are indicated on the drawing.
Fig. 2 is a longitudinal sectional view taken on ;~
Line II-II in Fig. 1 ant showing the equipment.
Fig. 3 shows a simpliflet modificstion of the equipment shown in Pigs. 1 and 2. This modiied equipment can preferably be accommodatet, e.g., in the basements of agricultural buildings because it is designed to be movable through existing door openings.
It is apparent rom Figs. 1 and 2 of the drawing that the equipment for heat-treating said fuels comprises fuel supply containers 1~ which consist of two individual shafts, which are arranged like the legs of trousers and ~-as shown in Fig. 2 are rectangular in cross-section each.
The upper regions of the shafts ~oin in a common rectangular fuel supply hopper, which is adapted to be closed by a cover 2, which is displaceable at right angles to the plane of the drawing of Fig. 1 on rolling elements~
which may be replaced by slide rails in combination with means for lowering the cover 2 in closing position -- 10 _ , . ~ . , .
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so that a seal is obtained between the cover and a flange that surrounds the common mouth of the shafts. The shaft assembly is surrounded by a reactor wall 3~ which is lined by heat insulation 4. Parts 3, 4 are spaced around the shaft -assembly 1 to define a space 5 which at its upper end is designed to supply a quantity of air or oxygen to a first stage. The air supply rate is suitably ad~ustable by means of adjustable dampers 6 or louvers 7. In the embodiment of the invention shown by way of example on the drawing, it is assumed that the fuel to be supplied to the shaft assembly 1 consists of precompacted or highly compacted bales of straw, one of which is shown because it has just entered the left-hand shaft tube. Below the bale of straw which is shown there are some diagrammatically indicated blocks of wood. It has been found that the use of such blocks of wood is suitable so that the partial quantity of air -~
or oxygen to be supplied to the first stage can flow around each bale of straw. The lower openings of the individual shafts are held in a flange assembly 8, which merges into a hollow inner chamber 9, which deflnes a cavity having the same reference numeral 9. The inner chamber 9 is closed at its outside periphery by a holder 11 for refractory bricks or by a fireclay lining 10. There is also a metallic outer chamber 12, which has the shape of a downwardly open bell and is reinforced at 13 at its lower end. A jacket space 14 defined by the chambers 9, 12 is closed at its upper end by the annular flange 15. The refractory wall 10-12 which surrounds the space 9 may be replaced by a casting or by a pot of high-temperature -`~ 1062087 steel and has passages 16 and 17 in the form of nozzles, specifically air nozzles, because the apertures forming said passages open into the ~acket space 14, which constitutes an air supply space and which communicates with the outer ~`
shaft space 5 through the free annular cross-section that ad~oins the reinforcement 13 and serves to supply air to ~;
space 14. The nozzles 16 are much larger in cross-section ~-than the nozzles 17. The ratio of the cross-sections is about 10:1. This relationship of ~he cross-sections is required owing to the fact that the reactions used to ~
produce gas fractions should take place mainly in the ~ ~-upper region of the space whereas in the lower region, which is supplied with less air through the nozzles 17, only those reactions are to be perormed which serve to prevent in the lower region of the space 9 a retention by fuel which has not been distilled or gasified and/or burnt. Alternatively~ the nozzles 16, 17 may have the same cross-sections and may be provided with mutually concentric refractory inserts in order to optimize the conditions in dependence on variables such as the nature -of the fuel, its moisture content, different fuels levels in the individual shafts, etc.
It is apparent from Fig. 1 that the equipment is symmetrical with respect to its center plane, which is designated 18 in Fig. 1~ whereas the illustrative embodiment shown in Fig. 3 is asymmetrical.
The space 9 which ConstitUteS the hollow chamber having the same designation is closed by a fixed bottom 21, -_ 12 -which is heat-insulated. Alternatively, the bottom 21 may be double-walled and be designed, e.g., as a duct for conducting gas which has been produced. Because that gas i9 free from i`
oxygen, the ad~oining metallic portions cannot scale. When the equipment is supported on undisturbed soil~ which should ;
be dry, it is not necessary to provide a separate foundation nor a separate heat insulation but the gas duct thus formed may be enlarged to form a space which surrounds heat I
exchange means.
A hollow box extends at right angles to the plane of the drawing in Fig. 1 through the hollow chamber 9, which is identical to the space 9. In the embodiment shown by way of example, the hollow box constitutes a cylindrical tube 19. In accordance wlth Fig, 2~ rows of nozzlelike inlets 20 are arranged in the tube wall 19. An inner tube 22 is concentric to the outer tube 19 and i9 described as a burner tube because the space 23 between the tube walls 19 and 22 acts as an agitating, mixing and collecting `-chamber, which is defined by an end wall 26. On the other hand, because the inlet nozzles 20 form constrictions owing to their smaller cross-sections of flow the outer tube 19 separates that portion of the space 9 which receives the gas fractions and is disposed outside the outer tube 19 from the agitating, mixing and collecting spaces 23. As a result, a common gas stream of the kind which is similar to the illuminating gas~ town gas~ coke oven gas, blast furnace gas or natural gas supplied to gas burners and which is a common gas stream because it contains all gas fractions is formed in that portion of the space 23 which `` 1062087 is on the left in Fig. 2.
Air supply means generally designated 27 are dlsposed centrally with respect to the agitating and . . .
mixing chamber 23 and are preceded by an air-receiving 1 funnel 28 and a control valve 29, which may be automatically controlled in dependence on a variable. The air supply means open in an air supply nozzle 31, which is disposed within `-the burner tube 22 so that the supply of gas which is combustible or at least contains combustible matter through the ~acket space 23 and the agitating and mixing chamber, which is open to the burner tube, in con~unction with the heating of gas and air by the surrounding fuel ~ -result in the conditions required to produce a burner flsme 32. Such arrangement may be described as a straw burner ln analogy to a gas burner. Whereas smaller arrangements of this kind do not require adtitional flow-dynamical ;
measures~ these are required with larger types of straw burners, For this reason, guide walls 30 are provided, which concentrically surround the air supply mea~s 27 and are similar to a Venturi tube and are perforated to be permeable to the gas mixture so that the latter ~
is not only sucked by an e~ectorlike action to produce -a subatmospheric pressure in the reactor but the mixture formed by the gas fractions is agitated once more to provide the conditions required for the formation of the elongated burner flame 32, which fills the tube 22. -The suction produced by the e~ector 30, 31 mi8ht also be produced by a conventional suction blower and could be increased by a fan. me walls 34, 35 which are shown in ' 1062087 Fig. 2 and form boundaries of the overall equipment on the left and right are also protected by insulation from heat losses. The burner tube 22 pro~ects at 33 beyond the insulation 4 of the wall 35 so that an exhaust gas pipe for discharging the hot gases can be connected by a flange assembly 36. The exhaust gas pipe may incorporate a chamber for accommodating a catalyst 38, by which a catalytic ;
afterburning may be effected if this is required or at least suitable.
It is indicated at 48 in Fig. 2 that equipment embodying the invention may be succeeded by a container for accommodating one or more heat exchangers. In this case the exhaust condult 37 open~ into the container unless it is preferred to arrange such heat exchangers separately, e.g., behind grain-dryers, if the hot gases leaving the same still contain heat which can be utilized in heat exchangers. m e inverse arrangement may also be adopted, for instance~ when drying is to be effected at temperatures which for biological reasons do not exceed an upper limit of an order of 30 to 40 C (SCHANDERL).
It is apparent from Fig. 1 that the shaft assembly comprising the two individual shafts 1 comprises also a guide body 42 for the bales of straw used as a fuel.
That guide body has closed boundary surfaces 43~ 44, which are inclined toward each other. me guide body 42 is disposed above the straw burner assembly 20 to 36. A
different, asymmetrical arrangement of the burner assembly relative to tne shaft assembly 1 is shown in Fig. 3, in which parts having the same designations are identical _ 15 -.. . . .
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:.;.`., to the parts of the embodiment shown by way of example in ~ --Figs. 1 and 2. For this reason there is again an inner ;
hollow chamber, which encloses the space 9, but the outer tube 19 together wlth the inner tube 22 and the agitating, --mixing, collecting and gas-stream-forming jacket space 23 ~
.~ . . - .
is laterally offset from the inner hollow chamber so that a guide wall 47 is required to define for the fuel which has entered the shaft 1 the path along which the fuel is -~
degassed or distilled, then gasified and partia~lly burned, -whereafter a mixed gas is formed and the combustible matter in the resulting gas stream is completely burnt. m e tube 19 is perforated at 20.
The embodiment shown in Fig. 3 is particularly , sultable for the manufacture of relatively small straw burners so that such equipment, possibly with an assoclated heat exchanger, may be subsequently installed and may, e.g., be transported through existing doors in basements, barns, workshops~ fodder-heating rooms, etc.
The dotted lines 40 in Figs. 1 and 3 indicate passages which extend through the shaft walls and are adapted to be closed by covers 41. These passages serve, e.g., to enable the introduction of igniters, igniting torches, igniting devices or igniting materials into the shaft spaces or hollow chamber spaces, also to enable an elimination of a stagnation in the flow of fuel and to enable other necessary interventions into the degass~ng~
distilling, gasifying, mixing and agitating processes.
This relates also to the introduction of flexible suction tubes for a removal of ash. Because the heat treatment of 106Z087 ;-.:
the fuel is suitably effected, as has been described, in such a manner that all treatment spaces are subjected to subatmospheric pressure, e.g., in that the suction tube of a blower is connected to the outer jacket tube 19 or the exhaust gas tube 37, although the use of different means of sub;ecting the treatment spaces to subatmospheric pressure does not appear to be basically excluded, a change-over to the above-mentioned flexible suction tube will permit of a rapid withdrawal of the ash, which is particularly light in weight and easily movable in the case of straw.
The partial quantities of air or oxygen to be supplied in the first or second and, if desired~ in a ~ ~-succeeding stage may be controlled in such a manner that a complete combustion does not re~ult but only straw charcoal is finally produced. Gwing to the chemical composition of grain straw, straw charcoal can form activated charcoal having activity properties in a degree which cannot be found~ e.g.~ in wood charcoal. For this reason the straw charcoal which has been produced may be converted into activated charcoal so that the process which has been proposed has a previously unknown importance ;
as a preliminary stage in the production of activated charcoal, particularly because straw charcoal can be produced first and activated charcoal can be continuously produced from straw charcoal in a fluidized-bed process.
What has been explained with reference to straw as a fuel is analogously applicable to any other fuel, which is preferably of organic origin and which tends to form tar. Shells, beans and pods are suitably bonded ~ 1062087 ~``
.. . .
with the tar as a binder to form pellets. This tar may be r~
produced, e.g., in that the measures proposed according to the invention in order to avoid a formation of tar are omltted intentionally and according to plan. Shells or peels are those of nuts, chestnuts, almonds, particularly of peanuts~ the peels of potatoes, bananas etc. Suitable beans are soybeans and suitable pods those of lupines and leguminous plants. ~
The reactor proposed for carrying out this process ~;
contains a hollow chamber, which in the direction of gravity -succeeds shaftlike fuel containers, and a transverse tube, -~
which extends through the hollow chamber. -In conclusion~ the following remarks are made concerning the mode of operation of the equipment which has been shown on the drswings and described.
Initlslly, the compartments of the shsft assembly which sre defined by the walls 43, 46 and 42, 47~ respectively, ;-and serve for the storage of fuel are supplied with fuel as ;, is indicated in Fig. 1. When the plant is cold, the bales which have been charged first fall by gravity and build up first in the inner hollow chsmber 9 and subsequently in the individual shaft spaces. When the cover 2 has been closed, the ignition is initiated. Igniting devices which have been ~;
incorporated in the chamber 9 msy be used for this purpose.
Under the action of the suction and of the supply of part of the air or part of the oxygen through the nozzles 16, 17, the ignition spreads immediately to the lowermost bales of straw so that the temperature in the inner hollow chamber 9 rises within very short time and results in degassing, dry ` 1062087 ~
distillation, thereafter in gasification and partial combustion. These effects are produced already in the space 9 of the lnner hollow chamber, in which the resulting gas fractions begin to mix. Owing to the constrictions 20 in con~unction with the ~acket space 23 which wides from said constrictions, the gas fractions are strongly agitated and ~ ;
their mixing is intensified and the gas fractions are collected. These gas fractions consist of distilled-off gases, air gases and combustion gases but still contain combustible residual gases, such as CO (carbon monoxide), hydrocarbons, and free carbon, so that the formation of the flame 32 begins in the antechamber of the combustion tube 22 - this antechamber is defined by the end wall 26 -in conJunction with the partial quantity of air or oxygen suppliet ln the second state. The processes which have been described promote each other BO that the temperature increases progressively and the delivery of hot gases through the exhaust gas pipe begins whereas there is no formation of smoke. Neat exchangers may be contacted by the hot gases and may serve to heat and, if desired, i-evaporate a fluid such as water which is conducted through them. Finned tubes may be used to increase the heating surface area as much as is required. Warm or hot water thus produced may either be supplied directly for various purposes, including the heating of residential and work rooms, also the supply of dry heat, which is required in large quantities for the production in agriculture, horticulture and forestry, e.g., for draing grain or animal feed, for producing dried milk, etc. It need :` 106Z087 `~
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not be emphasized that similar remarks are applicable to ~-ind~serial production.
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- 20 - .
... . . .
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To cope with the problems involved in such processes, a number of proposals have already been made with the ob~ect of controlling the process in such a manner that neither during operation nor during inevitable ^-cooling periods which are due to interruptions in operation `
there will be a deposition of tar on heat exchange surfaces which belong to heat exchangers required for purposes of heat economy. A deposition of tar on such heat exchange surfaces would result in a decrease of the thermal efficiency of equipment serving to carry out the process below tolerable values. A basic solution which has also been proposet already is characterized in that the hydrocarbon-containing gases are forced through zone8 which are at very high tem~peratures so that the hydrocarbons are cracked in these zones and can no longer deposit on said heat exchange surfaces as tar layers which would give rise to the above-mentioned dangers because the fluid to be heated, consisting in most cases of water, is usually at room temperature at its initial contact with heat exchange surfaces so that the requirements for condensation are inherently fulfillet.
It has also been found previously that it is inherent in the nature of the above-mentioned fuels that dry distillation may result in an unexpectedly strong development of gas, which can be described as a stream of distilled-off gas, produced by dry distillation, during the time in which the above-mentioned ~he treatment results in higher fuel temperatures and consequently in exothermal reactions. That stream tends to displace the ~06Z087 oxygen~ which is generally supplied as combustion air or -oxygen-enriched air and is required for a regularly effected ,~ -pregasification and at least partial combustion. As a result, pockets of distilled-off gas may be preserved even in the oxidizing zone~ so that tar-containing gases which have not been decomposed leave the oxidizing zone although cracking temperatures occur in said zone. That detrimental phenomenon has been suppressed in that the combustion air was supplied in partial streams along the path which is tefined for the fuel by the equipment for carrying out the process. In this way, the cloud of -distilled-off gas was divided and a formation of pockets of distilled-off gas W8S avoided.
In accordance with a new lnventive recognition the above-mentioned difficulties can be eliminated in a different, atvanced manner. This recognition is based on the fact that the fuels from which the above-mentioned hydrocarbons are derived which tend to form tarlike condensates are malnly surplus products of agriculture, ~`
horticulture and/or forestry and/or their wastes, which have recently been described as residual products. Whereas the first alternative is and will remain an only intermittently occuring special case, which cannot been taken into account in any planning relating to energy economy, the above-mentioned wastes become available regularly and in enormous quantities in con~unction with the provision of food for human beings and animals. So far, the removal of these wastes has adversely affected a desired ecological condition.
For instance, in Germany alone about 25 million metric tons - ` 1062087 :
of grain straw become available per year and the systematic thermal utilization thereof by degassing or dry distillation, gasification and combustion would decrease the required petroleum imports by about 12%. When it is considered that residual products in the form of wood, legumes, dry shrubs and tops etc. become available in quantities which are not smaller and that the same remarks are applicable to waste products from imports, the energy gap can be reduced to an even larger extent. It is of very high significance that a utilization in accordance with the invention can be carried out in an ecologically ~;
satisfactory manner and that the annual aftergrow will prevent an eventual complete exhaustion of the world resources of other energy sources. The above-mentioned energy deficiency cannot be closed by nuclear power.
Until 1985, 4000 metric tons of uranium fuel will be present in Germany alone and will increase by one fourth per year. Within at least ten years, a large-scale plant which is to be erected in the meantime will have to be ;
used to separate iodine 129 by 99% krypton 85 by 90%, and tritium by 75 to 80%; the remainder is to be discarded anyway. In an aqueous solution, 509 grams of plutonium 239 constitute a critical mass which is sufficient for an explosion. In 1985 there will be 30 metric tons of fissionable plutonium in Germany. The element wh~ch emits the high-energy gamma rays is highly toxic chemically and decomposes to one-half only within 24 400 years. Whereas the decomposition can be accelerated by the addition of plutonium to the conventional reactor fuel elements as a fuel, this means . .
,,_ .~' ` ` 1062087 ~ ` `
that increasing quantities of the dangerous element must be tolerated in the nuclear reactors and even larger quantities of plutonium-containing materials must be transported. The `
ob~ects which have not yet been satisfactorily accomplished have thus been outlined. The presently contemplated storage `i in abandoned mines, in the abandoned stock-shaped bodies of salt from which potash salts have been recovered, or the submerging in the oceans are makeshift solutions, which are almost ridiculous in view of the above-mentioned ;
"~ ,:
half-value period of thousands of years. ;
These statements confirm the urgency and importance -of the recognitions on which the present invention is based~
which is characterized in that stored fuel which is preerably in the form of lumps, blocks, bales, bundles, sheaves, parcels~ columns~ layers or other compacted sccumulations or in the form of stacked, piled ar otherwise superimposed compacts, high-pressure compacts, pellets etc.
is sub~ected in a treatment chamber to an action of heat which results at least in degassing and/or dry distillation -and, in con~unction with a supply of oxygen, in gasification and in not more than partial combustion, and that resulting gas fractions are mixed and separately from the fuel supply are combined in a gas stream, which is then supplied with oxygen in the quantity which is required for a complete combustion of the combustible matter contained in said gas stream.
The invention which has thus been characterized :f' involves a number of novel technological effects which produce the desired result.
Because the formation of the gas fractions, the mixing thereof and the formation o a stream thereof and the only subsequently effected combustion of the still combustible matter are separated from the fuel supply, the interdependence of the means for supplying fuel and combustion air is eliminated. This interdependence is undesired for the reasons which have been explained hereinbefore. After an air flow region which desirably follows the direction of gravitation, a partial quantity of air or oxygen to be supplied in a first stage may be caused to flow in a second air or oxygen supply phase in a direction which is transverse to the direction of the partial quantlty of air or oxygen in the first phase so ~i that the dlrections of thè alr or oxygen and of the distilled-off gas cross. As a result, any cloud of distilled-off gas which may form ls reliably divided so that a formation of pockets of distilled-off gas is effectively opposed.
A second technological effect which i9 essential for the desired result and is highly advanced resides in that the agitating and/or mixing spaces and the gas steam-forming chambers which succeed the region in which the fuel has been fissured and disintegrated by dry distillation and at least partial gasification can be given that size which is sufficient for a thorough mixing of the gas fractions and for the formation of a decidedly mixed gas stream. A third successful technical effect resides in that the separate formation of the mixed gas stream, on the one hand, and the supply thereto of air , 1062087 ~
or oxygen at least in a partial quantity which is required for a complete combustion of the combustible content of the gas stream~ and generally in a much larger surplus, provide ~ ~
the conditions which are required for the known use of -gas-air burners of a design which results in virtually ldeal flow-dynamical conditions and in the high thermal efficiency which is typical for a complete combustion of a gas.
The nature of the invention may be summarized in that a deposition of tars in heat exchangers, exhaust gas conduits and chimneys in conjunction with the thermal utilization of fuels of organic origin and of combustible waste materials (straw, waste wood) is prevented in that the combustible material is permitted to move under the action of gravity and is then deflected to an approximately horizontal direction and while moving in the latter direction is degassed and incompletely burnt with cracking of the previously formed hydrocarbons. The resulting gas fractions are throttled, agitated, mixed, collected and transformed into a gas stream, which is supplied to a gas burner together with at least that quantity of oxygen that is required for a complete combustion of the combustible matter still contained in the gas stream in an existing or adjusted stoichiometric proportion to the oxygen which has been supplied.
It is inherent in the nature of the invention that is not necessary to mix all gaseous components which appear as fractions. For instance, individual fractions may be separated entirely or partly from other or all 106Z087 ;~
fractions and may be withdrawn and used directly and, if desired~ a remainder which cannot be utilized may -be returned to the agitating~ mixing and gas stream-producing spaces. This remark is applicable~ e.g.~ to the distilled-off gas fraction so that gaseous or vaporous -constituents contained in the distilled-off gas, such as chemicaily valuable pentosans, furfural, low-temperature tar vapor constituents etc., can be separately collected and utilized~ and constituents which are inert under the existing conditions, such as high-temperature nitrogen, carbon monoxide~ carbon dioxide can be returned into the treating equipment so that the heat content of these '-gaseous constituènts can be utilized in one or more heat exchangers.
Special advantages will be afforded if the above-mentioned treating methods are carried out under subatmospheric pressure. Advantages reside in that the equipment for carrying out the process can be sealed more easily, the combustion air can be supplied more easily in several stages, and the degree to which the ~`
gas fractions are mixed can be improved in that the air is supplied into the gas stream by an injector or ejector unless suction or pressure blowers, fans etc.
are preferred.
Whereas the above-mentioned details of the process ensure that each of the heat trea~ments mentioned can be carried out at the highest practicable efficiency, it may be justified in individual cases to supplement the process by a catalytic afterburning, especially because ..
` ~062087 ~
the process results in particularly favorable space conditions which enable the accommodation of one or more suitable catalysts. The same remarks are applicable to the accommodstion of one or more heat exchangers. It ~ -is particularly possible to provide a second wall, which is parallel to a wall of the treatment chamber and defines a compartment which communicates with and is flown through by gas which leaves the treatment chamber, and to provide one or ~ore heat exchangers, which are accommodated in the `
compartment and consist, e.g., of finned tubes flown through by a heat-absorbing fluid so that exhaust gases which are free from tar~ sulfur, vapor~ and smoke can be discharged into the environment without polluting the latter.
Further details of the process will be mentloned in con~unction with embodlments shown by way of example on s the drawings. `
Equipment which is suitable for carrying out the process is basically characterized in that a fuel storage container assembly is succeeded by a hollow chamber assembly for effecting at least a degassing and gasification and/or dry distillation and not more than a partial combustion and possibly a carbonization and for accommodating a gas burner, -which is preceded by agitating and premixing spaces and/or means, means are provided for collecting and for producing -a gas stream from the gas fractions that have been produced from the fuel and contain distilled-off gases, air gases and combustion gases, and means are provided which open into the hollow chamber assembly and the gas burner assembly and serve to supply air or oxygen.
`` 1062087 The drawing shows illustrative embodiments of equipment for carrying out the process which has been described and details of the process. In the drawing~
Fig. 1 is a transverse sectional view taken on line I-I in Fig. 2 and showing equipment which embodies the invention and serves to produce a gas by a heat treatment of fuels with formation of a gas which contains hydrocarbons that have been derived from the fuel and form tarlike condensates when cooled below their dew point. me `
fuel may consist, e.g., of bales of compressed straw, which are indicated on the drawing.
Fig. 2 is a longitudinal sectional view taken on ;~
Line II-II in Fig. 1 ant showing the equipment.
Fig. 3 shows a simpliflet modificstion of the equipment shown in Pigs. 1 and 2. This modiied equipment can preferably be accommodatet, e.g., in the basements of agricultural buildings because it is designed to be movable through existing door openings.
It is apparent rom Figs. 1 and 2 of the drawing that the equipment for heat-treating said fuels comprises fuel supply containers 1~ which consist of two individual shafts, which are arranged like the legs of trousers and ~-as shown in Fig. 2 are rectangular in cross-section each.
The upper regions of the shafts ~oin in a common rectangular fuel supply hopper, which is adapted to be closed by a cover 2, which is displaceable at right angles to the plane of the drawing of Fig. 1 on rolling elements~
which may be replaced by slide rails in combination with means for lowering the cover 2 in closing position -- 10 _ , . ~ . , .
``~
` 1062087 `:
so that a seal is obtained between the cover and a flange that surrounds the common mouth of the shafts. The shaft assembly is surrounded by a reactor wall 3~ which is lined by heat insulation 4. Parts 3, 4 are spaced around the shaft -assembly 1 to define a space 5 which at its upper end is designed to supply a quantity of air or oxygen to a first stage. The air supply rate is suitably ad~ustable by means of adjustable dampers 6 or louvers 7. In the embodiment of the invention shown by way of example on the drawing, it is assumed that the fuel to be supplied to the shaft assembly 1 consists of precompacted or highly compacted bales of straw, one of which is shown because it has just entered the left-hand shaft tube. Below the bale of straw which is shown there are some diagrammatically indicated blocks of wood. It has been found that the use of such blocks of wood is suitable so that the partial quantity of air -~
or oxygen to be supplied to the first stage can flow around each bale of straw. The lower openings of the individual shafts are held in a flange assembly 8, which merges into a hollow inner chamber 9, which deflnes a cavity having the same reference numeral 9. The inner chamber 9 is closed at its outside periphery by a holder 11 for refractory bricks or by a fireclay lining 10. There is also a metallic outer chamber 12, which has the shape of a downwardly open bell and is reinforced at 13 at its lower end. A jacket space 14 defined by the chambers 9, 12 is closed at its upper end by the annular flange 15. The refractory wall 10-12 which surrounds the space 9 may be replaced by a casting or by a pot of high-temperature -`~ 1062087 steel and has passages 16 and 17 in the form of nozzles, specifically air nozzles, because the apertures forming said passages open into the ~acket space 14, which constitutes an air supply space and which communicates with the outer ~`
shaft space 5 through the free annular cross-section that ad~oins the reinforcement 13 and serves to supply air to ~;
space 14. The nozzles 16 are much larger in cross-section ~-than the nozzles 17. The ratio of the cross-sections is about 10:1. This relationship of ~he cross-sections is required owing to the fact that the reactions used to ~
produce gas fractions should take place mainly in the ~ ~-upper region of the space whereas in the lower region, which is supplied with less air through the nozzles 17, only those reactions are to be perormed which serve to prevent in the lower region of the space 9 a retention by fuel which has not been distilled or gasified and/or burnt. Alternatively~ the nozzles 16, 17 may have the same cross-sections and may be provided with mutually concentric refractory inserts in order to optimize the conditions in dependence on variables such as the nature -of the fuel, its moisture content, different fuels levels in the individual shafts, etc.
It is apparent from Fig. 1 that the equipment is symmetrical with respect to its center plane, which is designated 18 in Fig. 1~ whereas the illustrative embodiment shown in Fig. 3 is asymmetrical.
The space 9 which ConstitUteS the hollow chamber having the same designation is closed by a fixed bottom 21, -_ 12 -which is heat-insulated. Alternatively, the bottom 21 may be double-walled and be designed, e.g., as a duct for conducting gas which has been produced. Because that gas i9 free from i`
oxygen, the ad~oining metallic portions cannot scale. When the equipment is supported on undisturbed soil~ which should ;
be dry, it is not necessary to provide a separate foundation nor a separate heat insulation but the gas duct thus formed may be enlarged to form a space which surrounds heat I
exchange means.
A hollow box extends at right angles to the plane of the drawing in Fig. 1 through the hollow chamber 9, which is identical to the space 9. In the embodiment shown by way of example, the hollow box constitutes a cylindrical tube 19. In accordance wlth Fig, 2~ rows of nozzlelike inlets 20 are arranged in the tube wall 19. An inner tube 22 is concentric to the outer tube 19 and i9 described as a burner tube because the space 23 between the tube walls 19 and 22 acts as an agitating, mixing and collecting `-chamber, which is defined by an end wall 26. On the other hand, because the inlet nozzles 20 form constrictions owing to their smaller cross-sections of flow the outer tube 19 separates that portion of the space 9 which receives the gas fractions and is disposed outside the outer tube 19 from the agitating, mixing and collecting spaces 23. As a result, a common gas stream of the kind which is similar to the illuminating gas~ town gas~ coke oven gas, blast furnace gas or natural gas supplied to gas burners and which is a common gas stream because it contains all gas fractions is formed in that portion of the space 23 which `` 1062087 is on the left in Fig. 2.
Air supply means generally designated 27 are dlsposed centrally with respect to the agitating and . . .
mixing chamber 23 and are preceded by an air-receiving 1 funnel 28 and a control valve 29, which may be automatically controlled in dependence on a variable. The air supply means open in an air supply nozzle 31, which is disposed within `-the burner tube 22 so that the supply of gas which is combustible or at least contains combustible matter through the ~acket space 23 and the agitating and mixing chamber, which is open to the burner tube, in con~unction with the heating of gas and air by the surrounding fuel ~ -result in the conditions required to produce a burner flsme 32. Such arrangement may be described as a straw burner ln analogy to a gas burner. Whereas smaller arrangements of this kind do not require adtitional flow-dynamical ;
measures~ these are required with larger types of straw burners, For this reason, guide walls 30 are provided, which concentrically surround the air supply mea~s 27 and are similar to a Venturi tube and are perforated to be permeable to the gas mixture so that the latter ~
is not only sucked by an e~ectorlike action to produce -a subatmospheric pressure in the reactor but the mixture formed by the gas fractions is agitated once more to provide the conditions required for the formation of the elongated burner flame 32, which fills the tube 22. -The suction produced by the e~ector 30, 31 mi8ht also be produced by a conventional suction blower and could be increased by a fan. me walls 34, 35 which are shown in ' 1062087 Fig. 2 and form boundaries of the overall equipment on the left and right are also protected by insulation from heat losses. The burner tube 22 pro~ects at 33 beyond the insulation 4 of the wall 35 so that an exhaust gas pipe for discharging the hot gases can be connected by a flange assembly 36. The exhaust gas pipe may incorporate a chamber for accommodating a catalyst 38, by which a catalytic ;
afterburning may be effected if this is required or at least suitable.
It is indicated at 48 in Fig. 2 that equipment embodying the invention may be succeeded by a container for accommodating one or more heat exchangers. In this case the exhaust condult 37 open~ into the container unless it is preferred to arrange such heat exchangers separately, e.g., behind grain-dryers, if the hot gases leaving the same still contain heat which can be utilized in heat exchangers. m e inverse arrangement may also be adopted, for instance~ when drying is to be effected at temperatures which for biological reasons do not exceed an upper limit of an order of 30 to 40 C (SCHANDERL).
It is apparent from Fig. 1 that the shaft assembly comprising the two individual shafts 1 comprises also a guide body 42 for the bales of straw used as a fuel.
That guide body has closed boundary surfaces 43~ 44, which are inclined toward each other. me guide body 42 is disposed above the straw burner assembly 20 to 36. A
different, asymmetrical arrangement of the burner assembly relative to tne shaft assembly 1 is shown in Fig. 3, in which parts having the same designations are identical _ 15 -.. . . .
` ~06Z087 `` `
:.;.`., to the parts of the embodiment shown by way of example in ~ --Figs. 1 and 2. For this reason there is again an inner ;
hollow chamber, which encloses the space 9, but the outer tube 19 together wlth the inner tube 22 and the agitating, --mixing, collecting and gas-stream-forming jacket space 23 ~
.~ . . - .
is laterally offset from the inner hollow chamber so that a guide wall 47 is required to define for the fuel which has entered the shaft 1 the path along which the fuel is -~
degassed or distilled, then gasified and partia~lly burned, -whereafter a mixed gas is formed and the combustible matter in the resulting gas stream is completely burnt. m e tube 19 is perforated at 20.
The embodiment shown in Fig. 3 is particularly , sultable for the manufacture of relatively small straw burners so that such equipment, possibly with an assoclated heat exchanger, may be subsequently installed and may, e.g., be transported through existing doors in basements, barns, workshops~ fodder-heating rooms, etc.
The dotted lines 40 in Figs. 1 and 3 indicate passages which extend through the shaft walls and are adapted to be closed by covers 41. These passages serve, e.g., to enable the introduction of igniters, igniting torches, igniting devices or igniting materials into the shaft spaces or hollow chamber spaces, also to enable an elimination of a stagnation in the flow of fuel and to enable other necessary interventions into the degass~ng~
distilling, gasifying, mixing and agitating processes.
This relates also to the introduction of flexible suction tubes for a removal of ash. Because the heat treatment of 106Z087 ;-.:
the fuel is suitably effected, as has been described, in such a manner that all treatment spaces are subjected to subatmospheric pressure, e.g., in that the suction tube of a blower is connected to the outer jacket tube 19 or the exhaust gas tube 37, although the use of different means of sub;ecting the treatment spaces to subatmospheric pressure does not appear to be basically excluded, a change-over to the above-mentioned flexible suction tube will permit of a rapid withdrawal of the ash, which is particularly light in weight and easily movable in the case of straw.
The partial quantities of air or oxygen to be supplied in the first or second and, if desired~ in a ~ ~-succeeding stage may be controlled in such a manner that a complete combustion does not re~ult but only straw charcoal is finally produced. Gwing to the chemical composition of grain straw, straw charcoal can form activated charcoal having activity properties in a degree which cannot be found~ e.g.~ in wood charcoal. For this reason the straw charcoal which has been produced may be converted into activated charcoal so that the process which has been proposed has a previously unknown importance ;
as a preliminary stage in the production of activated charcoal, particularly because straw charcoal can be produced first and activated charcoal can be continuously produced from straw charcoal in a fluidized-bed process.
What has been explained with reference to straw as a fuel is analogously applicable to any other fuel, which is preferably of organic origin and which tends to form tar. Shells, beans and pods are suitably bonded ~ 1062087 ~``
.. . .
with the tar as a binder to form pellets. This tar may be r~
produced, e.g., in that the measures proposed according to the invention in order to avoid a formation of tar are omltted intentionally and according to plan. Shells or peels are those of nuts, chestnuts, almonds, particularly of peanuts~ the peels of potatoes, bananas etc. Suitable beans are soybeans and suitable pods those of lupines and leguminous plants. ~
The reactor proposed for carrying out this process ~;
contains a hollow chamber, which in the direction of gravity -succeeds shaftlike fuel containers, and a transverse tube, -~
which extends through the hollow chamber. -In conclusion~ the following remarks are made concerning the mode of operation of the equipment which has been shown on the drswings and described.
Initlslly, the compartments of the shsft assembly which sre defined by the walls 43, 46 and 42, 47~ respectively, ;-and serve for the storage of fuel are supplied with fuel as ;, is indicated in Fig. 1. When the plant is cold, the bales which have been charged first fall by gravity and build up first in the inner hollow chsmber 9 and subsequently in the individual shaft spaces. When the cover 2 has been closed, the ignition is initiated. Igniting devices which have been ~;
incorporated in the chamber 9 msy be used for this purpose.
Under the action of the suction and of the supply of part of the air or part of the oxygen through the nozzles 16, 17, the ignition spreads immediately to the lowermost bales of straw so that the temperature in the inner hollow chamber 9 rises within very short time and results in degassing, dry ` 1062087 ~
distillation, thereafter in gasification and partial combustion. These effects are produced already in the space 9 of the lnner hollow chamber, in which the resulting gas fractions begin to mix. Owing to the constrictions 20 in con~unction with the ~acket space 23 which wides from said constrictions, the gas fractions are strongly agitated and ~ ;
their mixing is intensified and the gas fractions are collected. These gas fractions consist of distilled-off gases, air gases and combustion gases but still contain combustible residual gases, such as CO (carbon monoxide), hydrocarbons, and free carbon, so that the formation of the flame 32 begins in the antechamber of the combustion tube 22 - this antechamber is defined by the end wall 26 -in conJunction with the partial quantity of air or oxygen suppliet ln the second state. The processes which have been described promote each other BO that the temperature increases progressively and the delivery of hot gases through the exhaust gas pipe begins whereas there is no formation of smoke. Neat exchangers may be contacted by the hot gases and may serve to heat and, if desired, i-evaporate a fluid such as water which is conducted through them. Finned tubes may be used to increase the heating surface area as much as is required. Warm or hot water thus produced may either be supplied directly for various purposes, including the heating of residential and work rooms, also the supply of dry heat, which is required in large quantities for the production in agriculture, horticulture and forestry, e.g., for draing grain or animal feed, for producing dried milk, etc. It need :` 106Z087 `~
~ .
not be emphasized that similar remarks are applicable to ~-ind~serial production.
: .
,:
' .
~ .
- 20 - .
... . . .
Claims (24)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process of treating fuel of organic origin with formation of gases which contain hydrocarbons which form tarlike condensates when cooled below their dew point, which process comprises the steps of igniting said fuel to produce an initial temperature above the ignition temperature of the fuel, then subjecting said fuel to the action of the resulting heat whereby the fuel is at least degassed and at most gasified and subse-quently partly burnt, at the same time supplying the fuel with oxygen at least at the rate which is required for a gasification and at most at the rate which is required for a partial combustion of the fuel, throttling re-sulting gas fractions which contain distilled-off gases, air gases and combustion gases to separate said gas fractions from fuel which has not yet been heat-treated, then agitating said gas fractions and forming a common stream therefrom, and supplying oxygen to said gas stream at a rate which ensures that the stoichiometrical ratio of combustible matter still contained in said gas stream to the oxygen contained in the gas stream is sufficient for a complete combustion.
2. A process as set forth in Claim 1, in which oxygen is supplied to the fuel and to said gas stream at proportioned rates and at different pressure drops to the gasification and partial combustion process and to the complete combustion process.
3. A process as set forth in Claim 1, in which said degassing, gasification and partial combustion step and the complete combustion step are carried out under subatmospheric pressure.
4. A process as set forth in Claim 1, in which oxygen is supplied to the fuel and to said gas stream at proportioned rates and at different pressure drops to the gasification and partial combustion process and to the complete combustion process, said degassing, gasification and partial combustion step and the omplete combustion step are carried out under subatmospheric pressure, and said rates are proportioned in that said oxygen streams are throttled in different degrees at least before enter-ing their flow paths.
5. A process as set forth in Claim 1, in which oxygen is supplied to the fuel and to said gas stream at proportioned rates and at different pressure drops to the gasification and partial combustion process and to the complete combustion process, said degassing, gasification and partial combustion step and the complete combustion step are carried out under subatmospheric pressure, and said rates are proportioned in that said gas streams are throttled in different degrees at least in their flow path.
6. A process as set forth in Claim 1, in which said oxygen is supplied as atmospheric oxygen.
7. A process as set forth in Claim 1, in which said gas stream is deflected at least once before it is supplied with oxygen at the rate required for a complete combustion.
8. A process as set forth in Claim 1, in which a jacket stream is formed from the gases produced before the complete combustion and this stream is reversed to form an oppositely directed stream which contacts the jacket stream and which is supplied with oxygen at least at the rate required for a complete combustion.
9. A process as set forth in Claim 1, in which a jacket stream is formed from the gases produced before the complete combustion and this stream is reversed to form an oppositely directed stream which contacts the jacket stream and the opposit-ely directed core stream contacting the jacket stream on the inside thereof is supplied with oxygen at an adjustable rate which is sufficient for a complete combustion and along a flow path which is central with respect to the jacket stream and to the oppositely directed core stream.
10. A process as set forth in Claim 1, in which the resulting combustion gases are catalytically afterburnt.
11. A process as set forth in Claim 1, in which at least part of the sensible heat is extracted from the resulting combustion gases before they are discharged into the atmosphere.
12. A process as set forth in Claim 1, in which said degassing, gasification and partial combustion step and the complete combustion step are carried out under subatmospheric pressure and combustion residues formed in the process are sucked and conveyed by the action of said subatmospheric pressure and are deposited.
13. A process as set forth in Claim 1, in which at least one of the resulting gas fractions is withdrawn at least in part before said agitation and formation of a common stream and is utilized independently of the fractions which are agitated and included in the common stream.
14. A reactor for heat-treating fuels of organic origin with formation of gases which contain hydrocarbons which are adapted to form tarlike condensates, said reactor comprising, in combination at least one supply container assembly for said fuel, a hollow chamber assembly which succeeds said supply con-tainer asssembly in the direction of travel of the fuel and defines a cavity which is adapted to receive fuel for ignition and for a treatment with the heat produced in said hollow chamber assembly, means which define regions in the cavity of said hollow chamber assembly and also define regions in the interior of the reactor, said cavity having a first region, which directly adjoins the supply container assembly for the fuel and in which fuel that has already been predried in the supply container can be degassed with formation of distilled-off gases, said first region being adapted to receive the distilled-off gases, said reactor further comprising means for supplying said first region ? the hollow chamber with partial quantities of air or oxygen for gasifying and only partly burning the substantially degassed fuel in a second region of the cavity, which second region is adapted to receive the resulting air gas and combustion gases, said reactor comprising a region which is adapted to throttle, agitate, mix, and collect gas fractions consisting of distilled-off gases, air gases, and combustion gases and to combine said gases in a common gas stream, said reactor comprising a reactor region which succeeds the throttling, agitating, mixing, collecting and stream-forming region of the reactor in the gas flow path and accommodates a gas burner assembly, which comprises means for supplying addition-al air or oxygen at a rate which is sufficient for a complete combustion of the combustible matter contained in the gas stream.
15. A reactor as set forth in Claim 14, in which said means for supplying air or oxygen to the first cavity compartment of the hollow chamber assembly comprise nozzlelike passages in a wall which defines the cavity of the hollow chamber assembly.
16. A reactor as set forth in Claim 14, in which said means for supplying air or oxygen to the first cavity compartment of the hollow chamber assembly comprise nozzlelike passages in a wall which defines the cavity of the hollow chamber assembly and said reactor comprises a bell which extends over and is spaced around the hollow chamber assembly and defines therewith a jacket space which communicates with the nozzlelike passages in the wall of the hollow chamber assembly and which is provided with supply means for air or oxygen.
17. A reactor as set forth in Claim 14, in which said means for supplying air or oxygen to the first cavity compartment of the hollow chamber assembly comprise nozzlelike passages in a wall which defines the cavity of the hollow chamber assembly, said reactor comprises a bell which extends over and is spaced around the hollow chamber assembly and defines therewith a jacket ?ace which communicates with the nozzlelike passages in the wall of the hollow chamber assembly and which is provided with supply means for air or oxygen and said nozzlelike passages having different cross-sections of flow at different distances from the supply means for air or oxygen.
18. A reactor as set forth in Claim 14, in which the cavity of the hollow chamber assembly and the interior of the reactor are divided by means which include a wall that precedes the gas burner assembly in the gas flow path and has nozzlelike passages for the gas stream consisting of gas fractions.
19. A reactor as set forth in Claim 14, in which the cavity of the hollow chamber assembly and the interior of the reactor are divided by means which include a wall that precedes the gas burner assembly in the gas flow path and has nozzlelike passages for the gas stream consisting of gas fractions and said perforated wall consists of a hollow-cylindrical wall of a trans-verse tube, which extends through the cavity of the hollow chamber assembly and includes an outer tube having nozzlelike gas passages for throttling the gas stream and an inner tube consisting of a burner tube of the gas burner assembly.
20. A reactor as set forth in Claim 14, in which the cavity of the hollow chamber assembly and the interior of the reactor are divided by means which include a wall that precedes the gas burner assembly in the gas flow path and has nozzlelike passages for the gas stream consisting of gas fractions, said perforated wall consists of a hollow-cylindrical wall of a trans-verse tube, which extends through the cavity of the hollow chamber assembly and includes an outer tube having nozzlelike gas passages for throttling the gas stream and an inner tube consisting of a burner tube of the gas burner assembly, and air or oxygen supply means precede said inner burner tube in the gas flow path.
21. A reactor as set forth in Claim 14, in which the ?vity of the hollow chamber assembly and the interior of the reactor are divided by means which include a wall that precedes the gas burner assembly in the gas flow path and has nozzlelike passages for the gas stream consisting of gas fractions, said perforated wall consists of a hollow-cylindrical wall of a trans-verse tube, which extends through the cavity of the hollow chamber assembly and includes an outer tube having nozzlelike gas passages for throttling the gas stream and an inner tube consisting of a burner tube of the gas burner assembly, air or oxygen supply means precede said inner burner tube in the gas flow path and an injectorlike Venturi tube precedes said inner burner tube in the gas flow path and has a smallest cross-section which is identical with the outlet cross-section of the air or oxygen supply means.
22. A reactor as set forth in Claim 14, in which the cavity of the hollow chamber assembly and the interior of the reactor are divided by means which include a wall that precedes the gas burner assembly in the gas flow path and has nozzlelike passages for the gas stream consisting of gas fractions, said perforated wall consists of a hollow-cylindrical wall of a trans-verse tube, which extends through the cavity of the hollow chamber assembly and includes an outer tube having nozzlelike gas passages for throttling the gas stream and an inner tube consisting of a burner tube of the gas burner assembly and said inner burner tube is succeeded by a device which is permeable to combustion gas and adapted to accommodate a catalyst for afterburning combustible matter still contained in said combustion gases.
23. A process of treating fuel of organic origin with formation of gases which contain hydrocarbons which form tarlike condensates when cooled below their dew point, which process comprises the steps of igniting said fuel to produce an initial temperature above the ignition temperature of the fuel, then sub-jecting said fuel to the action of the resulting heat whereby the ?uel is at least degassed and at most gasified and subsequently partly burnt, at the same time supplying the fuel with oxygen at least at the rate which is required for a gasification and at most at the rate which is required for a partial combustion of the fuel, and throttling resulting gas fractions which contain dis-tilled-off gases, air gases and combustion gases to separate said gas fractions from fuel which has not yet been heat-treated, then agitating said gas fractions and forming a common stream therefrom.
24. A reactor for heat-treating fuel of organic origin with formation of gases which contain hydrocarbons which are adapted to form tarlike condensates, said reactor comprising, in combination at least one supply container assembly for said fuel, a hollow chamber assembly which succeeds said supply container assembly in the direction of travel of the fuel and defines a cavity which is adapted to receive fuel for ignition and for a treatment with the heat produced in said hollow chamber assembly, means which define regions in the cavity of said hollow chamber assembly and also define regions in the interior of the reactor, said cavity having a first region, which directly adjoins the supply container assembly for the fuel and in which fuel that has already been predried in the supply container can be degassed with formation of distilled-off gases, said first region being adapted to receive the distilled-off gases, said reactor further comprising means for supplying said first region of the hollow chamber with partial quantities of air or oxygen for gasifying and only partly burning the substantially degassed fuel in a second region of the cavity, which second region is adapted to receive the resulting air gas and combustion gases, said reactor comprising a region which is adapted to throttle, agitate, mix, and collect gas fractions consisting of distilled-off gases, air gases, and combustion gases and to combine said gases in a common gas stream.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA274,628A CA1062087A (en) | 1977-03-23 | 1977-03-23 | Process and apparatus for heat-treating fuels of organic origin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA274,628A CA1062087A (en) | 1977-03-23 | 1977-03-23 | Process and apparatus for heat-treating fuels of organic origin |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1062087A true CA1062087A (en) | 1979-09-11 |
Family
ID=4108229
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA274,628A Expired CA1062087A (en) | 1977-03-23 | 1977-03-23 | Process and apparatus for heat-treating fuels of organic origin |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1062087A (en) |
-
1977
- 1977-03-23 CA CA274,628A patent/CA1062087A/en not_active Expired
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