Patent Description:
The present invention relates to an apparatus for burning bales of material in a boiler in order to generate electricity. More specifically, the present invention relates to an apparatus that feeds bales of material into a multi-stage boiler for incineration, thereby providing heat to power a steam turbine or other power generation mechanism.

Boilers have been used for decades to burn oil, coal, wood and other materials in order to generate heat for powering a steam turbine, which in turn generates electricity. In recent years, efforts have been made to create boilers that are designed to burn bales, which are typically formed from a biomass material such as hay or straw. The following references describe various processes and mechanisms for burning bales in a boiler.

In the present invention, there is disclosed a process of burning biomass bales in a boiler with controlled supply of combustion air supplied through the mediation of a blower or an exhaust fan of combustion products into a combustion chamber through at least one nozzle in the direction variable in vertical plane wherein the invented burning process is characterized in that combustion air is supplied all over the time of the bale burning substantially tangentially to the upper burning surface of the bale and exhaust of combustion products takes place in the direction of the supplied air. There is also disclosed a boiler for making the above-described process wherein the boiler is provided with at least one nozzle (<NUM>) for supply of combustion air, said nozzle (<NUM>) projecting from said boiler combustion chamber (<NUM>) wall substantially at the level of a bale (<NUM>) upper surface a being rotatable about a horizontal axis, whereby exhaust of combustion products from the chamber (<NUM>) is situated at a place opposite to the nozzle (<NUM>).

A furnace <NUM> for cylindrical bales <NUM> of straw has support means <NUM> whereby the bale is rotated about an axis <NUM> while it is burnt and heat is transferred to water in a jacket <NUM>. Paddles <NUM> circulate partially burnt straw through the combustion zone. Air is injected tangentially with respect to the bale surface and in the direction of rotation. Bales are loaded into the furnace axially by an openable end cover <NUM> mounted on rails <NUM> and actuated by rams.

Boiler for burning whole bales of biomass, the boiler containing a combustion chamber (<NUM>) and a heat exchanger (<NUM>), said combustion chamber (<NUM>) containing a waste-gas flue (<NUM>) arranged in its top section and where the inlet (<NUM>) of waste gases into the waste-gas flue (<NUM>) is arranged on the side of the combustion chamber (<NUM>) which is opposite to the side with at least one intake (<NUM>) supplying the combustion chamber (<NUM>) with combustion air.

A biomass combustion boiler, particularly firing full biomass bales (<NUM>), contains a pre-heating chamber (<NUM>) and a combustion chamber (<NUM>). A closing plate (<NUM>) is located outside the pre-heating chamber (<NUM>), in its basic position, and is insertable into the pre-heating chamber (<NUM>). In its inserted position it divides the pre-chamber (<NUM>) into a lower space (<NUM>) freely connected with the combustion chamber (<NUM>) and an upper space (<NUM>) for newly supplied fuel. Fuel, particularly full straw bales (<NUM>), is supplied to the boiler by first inserting closing plate (<NUM>) into the pre-heating chamber (<NUM>), by then opening of a drop gate (<NUM>) of the pre-heating chamber (<NUM>) and inserting the fuel into the pre-heating chamber (<NUM>). The drop gate (<NUM>) of the pre-heating chamber (<NUM>) then closes and finally, the closing plate (<NUM>) is removed from the pre- heating chamber (<NUM>). A pusher pressure piston (<NUM>) conveys parts of the fuel from the bottom of pre-heating chamber (<NUM>) into the combustion chamber (<NUM>).

The furnace has a combustion chamber (<NUM>) which has a vertical panel separating it from the fuel feeder located over the ash collector (<NUM>). The secondary combustion air is admitted through an opening (<NUM>) in the rear panel (<NUM>) of the furnace. The exhaust gases pass through a heat exchanger (<NUM>) mounted over the combustion chamber. The ashes are raked by revolving arms (<NUM>) fitted with prongs. There is a base between the combustion and collecting chambers with a groove for the discharge of cinders and to induce the primary air.

The invention relates to a gasification boiler for the combustion of solid fuels, in particular bales of straw, for heating purposes and for the production of hot water. The inventive boiler is characterized by optimal combustion and ash separation. The aim of the invention is to carry out the combustion of small particles in the most complete manner possible and to achieve an almost total separation of the ashes from the combustion gas upstream of the heat exchangers. To achieve this, according to the first feature of claim <NUM>, the combustion and gasification chamber comprises lateral depressions that are configured next to the central grating and combustion chamber. Coarse particles collect in said depressions, leaving the fine particles to be carried with the combustion gas into the combustion chamber. According to the second feature of said claim, a cylindrical combustion chamber, configured as an additional component, is connected to the outlet of the combustion chamber. Said secondary combustion chamber significantly increases the combustion time, allowing small particles and partially oxidized gases to burn completely. According to the third feature, a cylindrical ash separator, configured as an additional component, is connected to the combustion chamber.

Heating boiler intended to be used for burning straw, paper and similar fuel material in the form of compressed bales. The boiler is capable of supplying the material to be burned as a function of the heat requirements. It is necessary to provide optimum combustion conditions to maintain exhaust gas emission values within prescribed limits. The boiler is therefore provided inside its combustion compartment with a channel (<NUM>) wherein the compressed bales are dried and the slow distillation gas is removed to a large extent from the fuel. The bale supply channel (<NUM>) opens into a combustion chamber (<NUM>) enclosing the combustion compartment and preventing the flames from touching the water jacket (<NUM>) of the boiler.

Each of the above-referenced documents describe boilers or furnaces designed to burn bales, which are typically made from biomass materials, but each also has disadvantages.

<CIT> discloses a device for the combustion of free-flowing solid fuel.

It would be advantageous to provide a boiler mechanism that transports and burns multiple bales of material, including biomass, and also bales that potentially include garbage, household waste, industrial waste, and the like, to create electrical power from waste products.

Disposing of household and industrial waste is an enormous global issue today, and a significant amount of such waste winds up in landfills and municipal dumps. It has been found that if household waste were formed into bales, the volume of space occupied by such waste would be reduced by approximately <NUM> percent, which would dramatically reduce the amount of land required to accommodate a dump. Further, if the bales of waste were then incinerated in a boiler used to generate electricity, then <NUM>) the pressure would be reduced on landfills and dumps, <NUM>) the environmental impact of the waste would be greatly reduced, and <NUM>) the waste would be converted into energy that may be used for any number of positive purposes, including being fed into the local power grid to provide inexpensive electricity to the populace.

<CIT> is directed to a mechanism for creating bales, and although the description included therein largely discusses baling wood chips and other similar biomass materials, such a baler may also be used to create bales of trash, waste and refuse.

In accordance with one aspect of the invention, a first embodiment of a bale boiler apparatus includes a multi-stage boiler and a conveyor for moving bales through the boiler for incineration. The boiler is operatively attached to a power generator, such as a steam turbine generator, so that heat generated by the boiler is used to turn the steam turbine for generating electricity.

The conveyor extends longitudinally through the boiler, and the bales are placed on the conveyor, which transports the bales into the boiler for incineration. The ash and any leftover waste are then carried out of the boiler by the conveyor and are deposited into a container or receptacle for transport and disposal.

The boiler includes at least three stages that the bales pass through. The first stage is a non-burning stage, where heat from the boiler is used to dry any moisture that is contained therein, and to generally warm the bale before incineration. The conveyor then moves the bale to the second stage, which is the main incineration stage. In the incineration stage, the majority of the bale is burned, which creates the vast majority of the heat used to power the steam turbine or other heat-based electrical generator. After the incineration stage, a small portion of the bale that is still left (along with any ash and non-combustible trash that is still present) is transported by the conveyor to the third stage, which is a supplemental incineration stage. In this third stage, the remnants of the bale are burned until only ash and non-combustible trash and refuse remain. When the third stage supplemental incineration stage is complete, then any remaining ash and non-combustible trash is moved via the conveyor out of the third stage and deposited into a receptacle for transport and disposal.

These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:.

The present invention, in a preferred embodiment, is a bale boiler <NUM> that incinerates bales <NUM> of material, and particularly bales <NUM> made from waste, garbage and other refuse, in order to provide heat for a steam turbine generator <NUM> (or for any type of electricity generator that is powered by heat). As shown in <FIG>, the bale boiler <NUM> includes a conveyor <NUM> for transporting bales <NUM> of waste material through a three-stage boiler <NUM>, and then removing the ash and non-combustible waste from the boiler <NUM> and depositing it in a receptacle or container <NUM> for transport and disposal.

The boiler <NUM> is preferably divided into three chambers <NUM> for three separate stages of the incineration process: <NUM>) a first chamber <NUM> used for the warming stage, <NUM>) a second chamber <NUM> used for the main incineration stage, and <NUM>) a third chamber <NUM> used for the supplemental incineration stage. In the warming stage, the heat from the main incineration stage is used to warm the bale <NUM> and remove any moisture that may be present. When the bale <NUM> is moved into the main incineration chamber <NUM>, it is burned to create heat that is then used to power a steam turbine electrical generator <NUM> or the like. At the end of the incineration stage, some of the bale <NUM> may remain burning and smoldering, and the remnants of the bale <NUM> are then moved by the conveyor <NUM> into the third chamber <NUM>, which is the supplemental incineration stage. In this third stage, the remnants of the bale <NUM> burn down to ash, and the remaining ash and non-combustible waste are then transported out of the boiler <NUM> by the conveyor <NUM> and dumped into a receptacle or container <NUM> for transport and disposal.

The bales <NUM> are preferably placed on the conveyor <NUM> in evenly spaced increments so that each bale <NUM> progresses through the successive stages in an orderly, cyclical fashion. In other words, if a first bale <NUM> is in the first chamber <NUM> of the boiler <NUM> and the time comes to move it into the second chamber, the conveyor <NUM> transports the first bale <NUM> into the second chamber <NUM>, and a second bale <NUM> (placed behind the first bale on the conveyor) moves into the first chamber <NUM> of the boiler <NUM>. The process is cyclical, so that the conveyor <NUM> moves the successive bales <NUM> into each stage and then stops while the incineration operation is underway. Then, when the bale <NUM> that is in the incineration chamber <NUM> has been mostly (but not necessarily completely) burned, then the conveyor <NUM> transports that bale <NUM> to the supplemental stage in the third chamber <NUM>, so that all bales <NUM> simultaneously proceed to the next successive chamber or stage.

It is contemplated that each chamber of the boiler <NUM> may be separated by doors or separators <NUM> that separate the different stages from one another during the incineration operation for each bale <NUM>. When it is time for the conveyor <NUM> to move the bales <NUM> to the next chamber and stage of the boiler <NUM>, the doors or separators <NUM> are opened to allow the bales <NUM> to pass therethrough, and then close again before the incineration operation begins on the next successive bale <NUM> in the queue. It is contemplated that this process may be operated manually, or automatically, based on temperature sensors <NUM> within the main incineration chamber <NUM> (or other types of sensors, such as laser sensors that detect the size of the bale, for example). Alternatively, the automated process may simply be a timed process, so that the bales <NUM> remain in each stage for a predetermined period of time.

The boiler <NUM> is operatively connected to a heat powered electric generator <NUM>, such as a steam turbine or the like, and the heat from the boiler <NUM> comes primarily from the main incineration chamber <NUM>, while a portion of the heat is provided by the third, supplemental incineration stage in chamber <NUM>.

The present arrangement allows for a series of bales <NUM> to be placed on the conveyor <NUM> for incineration, and the conveyor <NUM> and boiler <NUM> may run continuously, without interruption, so long as there are bales <NUM> being loaded onto the conveyor <NUM>. It is also contemplated that the boiler/ generator apparatus <NUM> may be formed into mobile unit and be transportable by truck to any desired location for generating electricity.

In general terms, heat powered generators typically require a great deal of time and effort to prepare the materials before the incineration process begins. Advantageously, the present invention reduces or eliminates the step of preparing the materials for burning, as the bales themselves may be burned without any preparation beforehand. The bale boiler apparatus and process allows the trash to be collected and baled, then stored (if necessary), and then to be burned in due course.

Claim 1:
A boiler apparatus comprising:
a multi-stage boiler (<NUM>) including a housing that is divided into three separate chambers (<NUM>) for various stages of an incineration process;
a first chamber (<NUM>) is used for a warming stage, a second chamber (<NUM>) used for a main incineration stage, and third chamber (<NUM>) used for a supplemental incineration stage;
a conveyor (<NUM>) extending longitudinally through each chamber of said multi-stage boiler (<NUM>), characterized in that
the boiler apparatus is a bale boiler apparatus; a heat powered electric generator (<NUM>) operatively connected to said multi-stage boiler;
wherein said conveyor (<NUM>) transports bales (<NUM>) of material through each chamber of said multi-stage boiler (<NUM>) such that said bales (<NUM>) are burned to generate heat; and
wherein said heat is used to power said heat powered electric generator (<NUM>) in order to produce electricity.