SE420619B - GAS GENERATOR AND USE OF THE SAME TO FUEL FUEL - Google Patents

Description

10 15 20 25 30 8861802- 1 for biofuels such as wood and peat but can also gas other gaseous fuels such as lignite, etc. the generator is particularly suitable for firewood, briquettes, logs, firewood etc. Chips and other comminuted fuels can however, can also be used. The dimensioning and detailed the shaping of the gas generator and its rust can be easy adapted to the preferred fuel.

The invention is based on a unique combination of geometric risk and thermochemical principles. A new design principle has been set for the gas generator functional elements to allow a new gasification course, which is adapted for the said preferred the special properties of fuels. A conventional gas generator rator is described in Swedish Offenlegungsschrift 348 752.

None of the known constructions they meet the above stated wishes as well as the present one invention which relates to a gas generator for gas-rich take fuels such as wood, peat and lignite with a fuel container with a grate, a grate chamber and a drain for the fuel gas characterized by a) that the grate is arranged in the fuel tank lower part and forms an angle with horizontal sontalplanet (b) that the rust compartment at the bottom is provided with for the supply of a reaction gas for gasification of the solid fuel in a narrow zone c) that the grate is made up of upward rust rods or rust elements d) that the grate room at the top is connected to the drain for the fuel gas with a gap or constriction.

The invention will now be described in more detail with the aid of 0991892-1 Figures 1, 2,3,4 and 5.

Figure 1 shows completely schematically the principle of the new one gas generator.

Figure 2 shows an expedient embodiment with external 5 providing constructive details.

Figure 3 shows different cross-sections for fuel tanks, rust and rust room.

Figure 4 shows a suitable rust construction.

Figure 5 finally shows a block diagram of a 10 spot system for an internal combustion engine.

Figure 1 shows the geometric conditions which in principle cip determines the gasification process in the new gas ratorn. The fuel tank (1) ends at the bottom with a oblique rust (2) carrying the fuel charge (3).

A reaction gas, such as preheated air, is fed to the roasting chamber (4) at the lower edge of the grate (5) via the inlet (6). The burning sludge formed in the narrow gasification zone (7) adjacent the grate (2) flows towards the gap (8) at the upper edge of the grate (9) where it exits to the gas outlet (10). The flow pattern is thus was completely different from conventional gas generators.

Figure 2 shows a gas generator according to the invention in a preferred embodiment. Figure 2 shows in the first place the constructive conditions which constitute a for the new procedure. The fuel tank (1), 25 in as 1 emznïulsskale can ne a length of about 1 meter and a square cross section of about 0.2 x 0.2 m ter, finish at the bottom with the grate (2) which like the fuel tank itself forms an angle to the horizontal 10 15 20 25 30 83-61 892-1 plane, preferably about 30-60 °. The rust needs however, not be arranged perpendicular to the main direction shown in Figure 2. The rust can e.g. lean 600 towards the horizontal plane and also the fuel tank the angle between the grate and the fuel tank housing significant extent also amounts to 600.

The specified range for the slopes 30-60 ° is suitable. values. The technical effect of the invention was achieved also at inclination angles for each element as can amount to as much as 70-75 °. In an extreme In this form, the fuel container is arranged vertically but finished at the bottom with an oblique rust with upward directed rust rods.

The fuel container (1) contains the fuel charge (3), for example firewood, which stands on the grate (2).

It is often appropriate to provide an additional horizontally arranged flat grate (II) for capture of non-fully gasified fuel which may fall laid out through the grate (2). The ash is collected in the ash box (12).

The reaction gas for the gasification can be e.g. of pre- air for partial combustion / gasification or with the addition of water steam described in a co-pending patent application "Methods for two-stage combustion of wood, peat and the like The reaction gas can also be supplied to a pulsating manner according to another also simultaneously administered heated hot flue gas or exhaust gas patent application "Method for pulsating gasification".

In the example according to Figure 2, however, air was used as incoming The air preheat in the heat exchanger (15) before the outlet (16). more via the drawbar (13) on the inlet pipe (14). 8901802- 1 The fuel gas formed flows upwards along the grate (2) against the gap or constriction (8). The column connects the rostrum (4) with the gas drain (10). The surface condition between the gap and the grate should be less than about 1: 5, a preferred value is about 1: 10 or less.

The gap or constriction (8) can consist of several parallel slots or slits or of a series of holes.

The temperature in the gasification zone should be in the range 550 - 950%, preferably 625 - 77s ° c a controlled by supply and composition of the reaction gas. One addition of recycled flue gas from the combustion of the gas can be made via the line (17) with the damper (18) and the fan (19). The hot fuel gas contains carbon monoxide, carbon dioxide, hydrogen, methane and other light hydrocarbons, tar substances, carbon black, water vapor and nitrogen as well as ev. existing sulfur and nitrogen compounds.

A very rapid pyrolysis and gasification of the fuel takes place in the narrow gasification zone. Pyrolysis and gasification the residue is oxidized by the oxygen in the reaction gas. Organizational nitrogen compounds are broken down into nitrogen. The equilibria do not have time to adjust why the fuel gas i.a. in- maintains a high content of methane. The fuel gas is suitably cooled in the heat exchanger (20) before use (applies to combustion engines).

It is surprising that the grip with the skewed ros- and the narrow gasification zone generate a fuel gas that can be burned completely and environmentally friendly.

An unambiguous explanation for this cannot be given. No of the known constructions, however, provide fast and intensive reaction processes in a narrow zone combined with all the gases formed leaving quickly to the gas the race. These conditions, which can be termed flash pyrolysis / gasification, gives according to the latest findings on this 10 15 20 25 30 SMHSGZ-'I area a fuel gas with higher fuel value and better combustion properties i.a. due to a higher methane slippery. amount of pyrolysis residue which is also more reactive at The pyrolysis also becomes more complete with less gasification and final combustion.

These favorable conditions are not achieved in the past gas generators characterized by more widespread assets zones and, as a result, slower thermochemical races and longer residence times for formed fuel gas with thermochemical conversion of the primarily formed pyrolysis the products as a result.

It may be added that the oblique rust_in the combination tion with the supply hub of reaction gas at its lower edge also provides other practical benefits such as good burning of the fuel charge. The remaining fuel co- read at the end of the process in the lower part of the grate where it brought into contact with incoming reaction gas which also provides efficient final combustion of the last residues of the pyrolysis and gasification residue.

The oblique rust in combination with a large fuel Lebe container also allows operation on partial power with a smooth process when using firewood. The firewood is set standing in the fuel tank and fills a larger electrical smiles smaller part of this so that the active narrow zone formed in a larger or smaller part of the rust from its lower edge. The exercise not used in this case re free part of the rust area can possibly be covered with and ev. adjustable screen plate. Those known for the invention intense pyrolysis and gasification conditions in this way can thus also be achieved with smaller fuel charges. 10 15 20 25 30 8-901892-1 The constructive design of the gas generator in can be based on the known technology of gas generating fireplaces and fireplaces in general. Figure 2 shows is guided completely schematically how condensate in fuel tanks the upper part of the net is caught in the trap (21) and then diverted to the vessel (22) with the drain (23). To- batch air can be supplied via the drawbar (24) and through the door (25).

The dashed lines (26) resp. (27) indicates gas generation inner and outer boundary surfaces of the tower. structure may be determined on a case-by-case basis location of the gas generator (indoor or outdoor) and other terms and conditions (traction or Materials and stationary application).

It is not necessary to describe here all these possibilities. embodiments as well as other conventional applications laying parts. There is also a plentiful market availability of suitable refractory alloys for the rust and other hot parts of the gas generator.

The main effect of the invention, the effective gasninq måste n must burn on the fast pyrolynum 1 don narrow the gasification zone (6) which gives a reactive fuel gas with i.a. methane 1 a content which far exceeds the equilibrium concentration and small amount of char. The average the residence time of the gas in the gasification zone is of large play order 1 second during normal operation to compare with residence times of the order of 10 seconds or in addition with known gas generators with fixed bed. This difference should have a great significance for the invention technical effect due to different thermochemical conditions countries, which most closely join the so-called flash pyrolysis 10 15 20 25 30 89618024 compared to slower processes in conventional gas generators As discussed above. Flow ratio the one for the gas flowing upwards along the oblique the rust also deviates most significantly from the conditions in the case of a vertically or horizontally arranged gasification ningszon. The flow conditions at the oblique the rust with its upward rust rods increases the speed for heat and matter transport between the gas phase and it solid phase.

A very small part of the fuel charge is each eye gaze affected by the gasification process. The process can popularly described so that the fuel charge is consumed as a cigar with the embers next to the rust. This process becomes particularly marked due to the fact that only the lowest len of the fuel charge participates in the process. Thanks to this, the effect can be quickly switched from "saving effect" to full effect and vice versa.

The regulation of the gasification process takes place, of course, by regulated supply of the reaction gas, e.g. air.

For simpler embodiments with natural and manual regulation of the tailgates under constant operating conditions elser you benefit from observation windows in to the restroom when adjusting the air supply. A fuel sledge thermometer and visual assessment of the gas that leaving the drain provides further guidance in or setting.

However, the gas generator according to the invention is very suitable well for automatic regulation. This area of technology is today well known with many proven solutions and I can therefore, limit myself here to specifying any appropriate principles of automatic regulation.

The design of the control system is conditioned by a number of conditions 10 15 20 25 30 89618024 such as (a) the size of the gas generator, (b) whether the fuel the gas was used for heating in a fireplace or as fuel for an internal combustion engine, etc., (c) the fuel properties not least prevalent quality variations, (d) if several different fuels are intended to be used; etc.

The regulation can also have different purposes. A purpose can be to control the supply of reaction gas for a constant and optimal gasification of the entire fuel charge to final. that the gas generator delivers the requested power Another purpose may be to control the process in this way under optimal gasification conditions.

It is often appropriate to control the supply of reaction the gas by means of mechanically acting control devices bimetallic type doors which are also comes generally in various stove and stove constructions.

Figures 3 a-f show a completely schematic section through various shaped fuel tanks in their lower part parallel to the rust. Figure 3a thus shows a through the fuel container (1) according to Figure 2.

The grate (2) has a square cross section in this embodiment. form of conduct. The long narrow gap (8) is delimited by fuel tank edge (9) 0Ch aVCrä fi S fl in9SYt ° rna ((23) (preferably brick). Figure 3b shows with the same drawings a fuel tank with a partially circular cross-section, whereby they from.gasification point of view smaller active lower corners of the grate according to Figure 3a elimi- neras. Figure 3c shows another variation with an arcuate slit (8) and a relatively elongated grate (2). Figure 3d shows a constriction with several columns (29) and Figure 3e a constriction consisting of several holes (30) .Figure 3 f shows a double rust with two rust surfaces which are opposite and joined to the beam (31) l Gknæmsamt for these is it 10 15 20 n 30 8991 8 32-1 10 oblique rust with the upward rust rods (32) which leads during the gasification formed fuel gas towards a gap next to the upper edge of the grate where the fuel gas escapes to the gas drain for recovery.which is fueled in a fireplace or an internal combustion engine.

The design and dimensioning of the grate (2) depends on many factors such as the nature of the fuel, the size of the generator, etc. The rust must retain the pyrolysis residue until it was completely burned. The thunder will then be pushed out through the grate and fall into the ashtray (12). Non-final combusted fuel is captured on the flat grate (ll) for final combustion. Pellet fuel requires rust elements smaller gaps or openings than conventional grids.

The rust must provide a fast and even supply of reactants. gas over the entire rust surface and an evenly distributed run of fuel gas. Another important practical desire goal is that it should be possible to without too much hassle remove pieces of unreacted material such as nails from construction waste, cans from household waste etc.

Many different rust constructions have been assigned and come Swedish patent 111352 writes fireplaces for magazine firing with skewed for practical use. rust. At this fireplace, the combustion takes place in a combustion chamber arranged under the grate whereby flows mainly downwards to the flue gas len. The principle of a temperature-influenced regulator for control of the air supply to the different parts of the rust can however, use is also made of the present invention.

Various artifices can be used to control the reaction. gas and fuel gas flows, for example through roasting iron with wings according to Swedish patent 5805 or through a grate with a gap size adapted for even reaction 10 15 20 25 30 G flfl18 B2-1 ll gas supply according to Swedish patent 7021. Rust the rods may be provided with air ducts according to Swedish patent 50499. More advanced rust constructions uses liquid cooling partly to recycle heat, and increase the life of the rust, for example Swedish patent 35168. Swedish patent 81188 describes such a liquid-cooled rust which is also and mobile.

It is not difficult for the person skilled in the art to utilize these rust structures and other known structures in the design of the grate with its upward-facing grate rods or other rust elements with the same function.

Figure 4 shows a simplest conceivable embodiment of the rust that meets all the requirements when burning firewood. The rust rods (32) are made of high alloy refractory steel and in this example has a width of 3 mm and a height of 3 cm. The rust stars are arranged as a grid grate using the transverse tie rods (33) and (34). The grille is conductively suspended in its upper edge against a rod (35) attached to the fuel the edge of the container (36). Figure 4 shows how the rust on one can be easily attached to the fuel tank by the two outermost rust stars and preferably some intermediate they are provided with appendages (37).

The rust is held against the lower edge of the fuel tank by means of the grate (38) attached to the lower strut rod (33). The rust roof rests against the fuel tank underside and is in its upper part designed as a handle take (39) as a locking grip (40) in the upper part of the heel holder.

You can easily clean the rust by loosening the handle and open the grate against the ash door, leaving the material on the grate collapses into the ashtray etc through the gap formed at 10 15 20 25 30 8901802-1 12 the lower part of the grate.

Figure 5 shows quite schematically the different components in a system for a truck. The gas generator earns the same purpose as a so-called gengasaggregat. However, it must be conventional gengas units work with one a completely different principle for the thermochemical production of the propellant. In the case of conventional threaded gas generators the propellant gas is set by reducing a combustion gas in a reduction zone in the so-called hearth containing wood carbon in a glowing state, as shown by e.g. the Swedish Explanatory Memorandum 348752 and many older Swedish patents such as 69137, 103821, 107230, 110100, 112171 et al. ffämßt of carbon monoxide and hydrogen.

The fuel component in this propellant is The propellant gas at the gas the rator according to the invention, on the other hand, is produced by a pyrolysis / gasification process that most closely resembles flash pyrolysis in which the propellant gas also contains a high content of k ° Vät @ n such as methane etc.

The gas generator in Figure S has a vertical fuel reservoir which ends at the bottom with an oblique rust. Fuel stomach sinet has a square cross section with the side 50 if and has a height of 120 cm. The slope of the frost is 450 and its surface thus 40% larger than a corresponding horizontal arranged rust. The fuel in this embodiment is pellets made from forest waste, peat, energy forest etc. with a diameter of about 15 mm. The slits in the grate between the grate rods has a width of 5 mm. Again- settling of the rust is prevented by the shaking at driving. The rust may be provided with a vibrating (41) or other device to counteract the setting. The fuel reservoir is surrounded by an external manhole tel (42) and perforated in its upper part so that delivered vapors may condense on the air-cooled surface of the jacket. 10 15 20 25 30 8601802- 1 13 The condensate is fed to the gasification zone via a special wire (43). formed according to the principle illustrated in Figure 2.

The gas generator is essentially The designations are also the same as in Figure 2.

The generator is otherwise designed according to the and design principles and with the materials developed for gengas units and which are suitable for large scale effect. A general description of the from gas-powered vehicles during World War II has been reported in the writing of the Academy of Engineering Sciences "Gengas" Stockholm (1950) - translated into English by Solar Energy Research Institute and available through NTIS, United States under the designation SP 33-140.

The fuel gas passes through a filter (44) and a reactor (45) for the elimination of higher hydrocarbons and carbon black as may accompany the fuel gas from the roasting chamber. The reactor (45) contains a sulfur-resistant catalyst (46) on nickel base for steam reforming. The fuel gas is then cooled in the radiator (47) which at the same time serves as a preheater for the air flow to the gas generator. The air flow is received via air intake (48). At start and acceleration is engaged the electrically driven fan (49). to the internal combustion engine (50) via the line (51).

The propellant is diverted Some of the exhaust gas from the internal combustion engine is returned with the reaction gas to the gasification zone of the gas generator via the conduit (52) provided with the damper (53). Exhaust- recirculation is not necessary but improves gasification significantly. An appropriate value for exhaust the recirculation is 5-20%.

Figure 5 also shows a device for adding water. steam to the reaction gas from the tank (54) with the exhaust gas 10 15 20 25 ~ 8001802- 1 14 heated evaporator (55) And line (56). The additive can be 0.1 - 0.4 kg water / kg dry fuel and may be adjusted according to the moisture content of the fuel. Water additive is not active applicable to steam reforming systems (45).

A gas generator according to Figure 5 has a given effect on about 70 kW. The methane content in the propellant gas amounts to about 0.05 Nm3 / kg fuel (analyzed before the reactor (45)). The fuel value depends on different circumstances so- such as the gasification temperature, the nature of the fuel and the humidity content but is often at the level l800-2200 Kcal / Nm3, i.e. significantly above the fuel value for propellant from conventional throttle units.

Adjustment of the system according to Figure 5 is suitably done using a miniaturized process computer. It is no difficulty for the person skilled in the art to for different types of fuels select appropriate additive systems and appropriate operating conditions for an aggregate containing gas the generator according to the invention as a central component.

Extensive experience that can be useful in this law exists from gengas operation of vehicles under it WWII The description has taken into account the special the signs of the gas generator according to the invention. A few preferred embodiments have also been described for to provide the professional with guidance in the application of the finding. The object of the invention is thus not limited to these particular embodiments.

Claims (1)

50 15 20 25 5091802-1 15 Patent application Claim 1 Gas generator for gaseous solid fuels such as wood, peat and lignite with a fuel container (1) with a grate (2), a grate chamber (4) connected to a drain (10) with a gap or constriction (8) for formed fuel axis is characterized by (a) that the grate (2) is arranged in the lower part of the fuel container (1) and slopes towards the horizontal plane (b) that the grate space (4) is arranged below the grate (2). ) and is provided at the bottom with devices (6, 1fi) for supplying a reaction gas for gasifying the solid fuel in a gasification zone (7) (c) that the grate is built up of upwardly directed rust rods or rust clement (32) (d) that the rust drum ( 4) at the top is connected to the drain (10) so that the streams of formed fuel gas are extended with the grate (2) towards the gap or constriction (8). Claim 2 Gas generator according to claim 1, characterized in that the grate (2) forms an angle with the horizontal plane within one '$': c1 <- t 3 016 Un. .w Claim 3 Gas generator according to claim 1, characterized in that the grate chamber (4) contains a flat grate (II). seto1so2-1 1G Requirement 4 Use for gas-rich solid fuels such as wood, peat and lignite to form fuel gas by means of Q a gas generator according to claims 1-3.