FR2864831A1 - Solid fuel, useful e.g. for industrial furnaces or electricity generation, is prepared from a mixture of plant biomass, of all origins, without use of chemical binders, produces ash useful as fertilizer - Google Patents

Abstract

Solid fuel (A), as nuts or briquettes, produced by treatment of plant biomass, where the plants used are of all origins (without exceptions), mixed together, from terrestrial, aquatic, urban, forest, agricultural or industrial sources. It contains no chemical additives that function as binders, since binding is supplied entirely by plant materials that become pasty during grinding.

Description

MANUFACTURE OF SOLID FUEL RESULTANT

  TREATMENT OF PLANT BIOMASS

FROM ALL ORIGINS

  Nature of the invention - Preamble The present invention relates to a new solid fuel, resulting from the treatment and recovery of plant biomass, all origins combined, whether its source is terrestrial or aquatic, of urban, forest, food or industrial origin . Without any chemical addition, composed of completely vegetable matter (ligneous and fibrous materials + pasty materials as binder), the invention will be disseminated under the name of Bois des Villes and is presented as a product resolutely ecological, totally respectful of the environment, virtually inexhaustible and thus generating renewable energy.

  It aims to gradually replace coal and oil in industrial thermal applications, and is likely to craft applications or a particular use without any adaptation.

  Easy to manufacture, requiring little equipment and requiring only very common and inexpensive technical means, Bois des Villes has the great characteristic of polluting very little, while giving off an energy comparable to that of a wood. heating of very good quality. It prevents deforestation and allows the implementation of materials generally abandoned in wild dumps, thus ending a very pernicious form of pollution.

  However, in France, two laws, which derive from European legislation, govern the treatment of waste: that of July 15, 1975, supplemented by that of July 13, 1992. These laws require the producer of waste to destroy them. This is the principle of the polluter pays, the automatic elimination at the expense of the producer can be implemented if necessary.

  According to these texts, any waste should be treated before being admitted to a landfill. The treatment can consist either in the direct and immediate recycling of the products with a view to their reintroduction in the economic circuit, or in the incineration, valorized or not by cogeneration (heat recovery, for example for district heating operations) . The legal texts admit in the final discharge only the indestructible clinker that results from incineration or waste that we do not know how to treat. In reality, the reality is quite different, because there are, in France alone, no less than 7,000 wild dumps to which no treatment is granted.

  When, however, it takes place, the succession of these operations leads to multiple transport and handling, which occur at each phase of the treatment and disposal of waste. Now, who says transport means pollution. Thus, pollutant pollution leads to the emission of carbon dioxide (CO2), nitrogen oxide (NOx), carbon monoxide (CO) and volatile organic compounds. (VOC). In fact, the truck transport of construction site waste alone is responsible for half of the total emissions from the waste transport activity, the rest representing the transport of household waste, local government waste and industrial waste. and agricultural waste.

  The average distance traveled by waste, all means of transport combined, is 43 km, with large disparities depending on the region. When we know that a dumpster consumes between 60 and 80 liter of fuel per 100 km, it is quite natural that the Bois des Villes is produced midway between the large human concentrations that generate it and potential users (thermal power plants, industrial boilers).

  With a very easy ignition, it does not produce polluting dusts and gives an ash of very high quality for agriculture. In addition, it self-compresses by strong shrinkage of the material drying, and is therefore content to be molded. This major quality avoids the need for expensive technical means of heating and pressing materials for shaping and to obtain the desired density. Notwithstanding this enormous facility, the fuel, presented as large or small balls, or logs, or briquettes, acquires the hardness of the wood as long as it is kept dry. Just like wood, a log of Bois des Villes burns in about two hours, without ever extinguishing prematurely or splinters likely to cause fires (case of special use), which is a guarantee of security that insurance companies will appreciate.

  It adapts without modification to all the combustion systems originally intended for charcoal or wood and can be used alone or mixed with charcoal or wood.

  Very inexpensive to produce, it can be manufactured either wherever human activities have developed, because a large concentration of plant biomass is available there, or still close to the users (thermal power plants, industries using steam, communities having need for heat, etc.), which is still halfway between biomass sources and users, a bit everywhere and in the form of small, well-distributed units that avoid long waste transport in urban areas.

  Respect for the environment - combating the greenhouse effect The current dynamic of any responsible state is the fight against climate change. The Kyoto Protocol, and the National Plan for Combating Climate Change and the National Energy Efficiency Improvement Program (NEEAP) that followed it, the EU Renewable Energy White Paper and more the new European directive on renewable electricity has considerably changed the context that should be further reinforced by the future biofuel directives.

  The increase in the concentration of greenhouse gases (water vapor, carbon dioxide, methane, CFCs, nitrous oxide, ozone) related to human activity, raises fears today a temperature increase in the next decades.

  Since the beginning of the industrial era, the carbon dioxide content of the atmosphere has already increased from 290 to 360 parts per million through the use of coal, oil and gas. Curving the progress of this pollution makes the most cautious scientists say that the total content calculated in carbon dioxide equivalent could triple by the year 2100, inducing major transformations of climate and planetary geography (acceleration of the cycle hydrological, rising sea levels, uninhabited coastal cities).

  As the 1992 Rio Summit made clear, the economic, social and health consequences will be significant and very difficult to manage, especially for poor countries that will have little means to adapt to these changes. At the Kyoto conference in 1997, some states accepted legally binding quantitative commitments to reduce or limit their greenhouse gas emissions over the 2008 - 2012 period.

  But of the 165 countries that signed the latter convention, only thirty have so far finally ratified it. The virulence of the debates at this conference is explained by the magnitude of the economic stakes: 90% of world energy is of fossil origin and releases CO2. Oil and coal lobbies fight energetically any attempt at limitation.

  As far as France is concerned, and without being a panacea, renewable energies (RE) represent one of the elements that will make it possible to meet international commitments to reduce greenhouse gas emissions and offer, in the medium term, valuable strategic alternatives in energy and petrochemical choices.

  The alarming rise in the price of oil emphasizes the sensitivity of all European countries to the price of this fuel whose fluctuations have the formidable power to disrupt many sectors of economic activity.

  Very worrying, a medium-term prospective study carried out for the European Commission indicates that growth in energy demand will result in an increase in imports of fossil fuels (coal, oil and gas). Europe's energy dependence, which remained below 50% in the 1990s, could be around 213 in 2020. Such dependence on fossil fuel imports would seriously undermine the long-term security of energy supply for Europe. all the European partners. It is therefore clear that fossil fuels, and mainly oil, occupy too much space in our societies.

  The Kyoto protocol provides that the signatory developed countries, including France, must fight their carbon emissions, to reduce by 8% by 2010. However, the growth of energy demand as expected in the European study would increase these emissions by + 7% in 2010 and + 14% in 2020! Notwithstanding these edifying considerations, we must be careful not to be utopian, for it is doubtful whether states can easily give up oil.

  Thus, in France, the most virtuous declarations of intentions coexist with, for example, the "2000 finance law" in which petroleum taxes (TIPP and VAT) represented the fourth state resource with more than 205 billion FF.

  By a healthy reaction, already, wood energy has returned to fashion following the environmental wave, especially in the countries of northern Europe. In France, the return to wood energy is encouraged in particular by aid and support from the State and some local authorities. Wood is the oldest fuel used by man. Also, today we rediscover its advantages: renewable, abundant, clean, distributed in space, almost neutral with regard to the greenhouse effect ... But at the beginning of the 21st century, it is considered irresponsible to cut the wood right and wrong. The lungs of the planet must be protected and, as far as possible, restored where it has already been badly damaged. As everyone knows nowadays, the forest is experiencing a terrible regression in Africa and South America. Bois des Villes, with its qualities equal to those of wood, is ideal for taking a relay that should allow, with the help of a good generalized information, to put an end to deforestation wherever it occurs.

  The biomass of plant origin manufactured under the name of Bois des Villes has cellulose as its main component. Its production may be fatal (by-products or waste from forestry, agricultural or industrial activities) or dedicated (specialized crops, short-rotation coppice). On average, biomass energy recovery is 0.4 toe / tonne. 1 m 3 of Bois des Villes logs sequester about 1 ton of CO2.

  The Bois des Villes manufacturing process does not use pyrolysis (85% carbonization which allows the transformation into charcoal by incomplete combustion). The pyrolysis plants, whether they are craft or industrial, are not very efficient as regards the carbonization of agricultural and agro-industrial waste. Only the semi-industrial method tested by the Senegalese company DELTA 2000 (specializing in husking rice) gives acceptable results in obtaining biomass coal.

  However, the results of the pyrolysis are generally disappointing because: - the amount of biomass coal required is 20 to 30% higher than that of charcoal for the same purpose; - biomass coal gives off smoke when fired; - it is more difficult to light than charcoal.

  - Whether it is artisanal, semi-industrial or industrial, pyrolysis must be rejected because of the highly polluting fumes that it releases into the atmosphere and which are practically never treated.

  The calorific value of biomass coal is not greater than that of Bois des Villes, and the 85% loss of the fuel volume is therefore not justified.

  Bois des Villes is therefore a fuel with high calorific value, very low pollutant, inexpensive, inexhaustible and whose sources are spread over the entire planet. It is also a "moral" product because its selfish appropriation by a great power, or its destruction by a terrorist movement is impossible, given the dispersion of materials absolutely everywhere on the planet and their accessibility to all, at any time.

  Why create Wood Cities in the DOM? In France and in the French overseas departments, the adoption of Bois des Villes would allow the country to be part of the logic of a proposal for a directive of the European Parliament and of the Council on the promotion of electricity from renewable energy sources. It plans to double the share of renewable energies in energy consumption in the European Union by 2010.

  It should also be noted that, in accordance with its public service status, EDF is required to respect the principle of equalization of rates: electricity is therefore billed at the same price throughout the national territory.

  Consequences: in the French overseas departments (DOM), where it is produced from conventional means (diesel groups), electricity costs more to produce than it is billed. The production of electricity is thus a sector chronically in loss. Since the consumption of electricity has already been multiplied by 5 since 1975 in the overseas departments, researchers are turning to all the energy solutions available to them. A privileged development of photovoltaic and wind power has therefore been ensured in the overseas departments: the EDF-ADEME agreement has been implemented on a larger scale in these départements than in metropolitan France.

  Wind power and solar energy are certainly attractive for the supply of isolated sites in these departments, but their implementation will still face the particular difficulty of access to certain isolated sites. The rugged terrain of the volcanic islands makes complex and expensive, and sometimes dangerous the laying of power lines able to withstand cyclones and other particularly violent storms.

  The substantial tax cuts enjoyed by the French overseas departments for investment in renewable energies greatly improve their profitability, but do not eliminate the aforementioned disadvantages.

  On the other hand, the high rate of unemployment of the overseas departments requires the implementation of projects generating jobs, but also likely to cause the hiring of very poorly qualified people, if at all. The Bois des Villes is therefore promoting equal opportunities. This is the social impact of this new fuel.

  This very attractive microcosm (strong energy needs + high subsidies + low-skilled unemployed) made DOMs perfect incubators for the launch of Bois des Villes. The ease with which a manufacturing can be launched, with inexpensive machines and unskilled personnel, makes it an essential solution for the recovery of green waste of any kind in the DOM.

  Finally, the launch of a new fuel derived from the treatment of plant biomass is particularly indicated in the French overseas departments because of the existence of sugar factories, major consumers of coal, heavy fuel oil and bagasse. Formerly, it took 6 kg of bagasse to produce 1 kWh. The improvement of the efficiency of the generators allows today to produce 1 kWh with barely 2 kg of bagasse. The Wood of the Cities having the calorific value of the wood (ie superior to that of the bagasse), it does not disappoint the industrial users of bagasse and coal, especially as it does not require any installation of the facilities current, neither at the level of the burners, nor that of the mechanisms of feeding. We can get an idea of the magnitude of the proximity energy represented by the transformation of vegetable biomass into Wood of Cities.

  For example, in metropolitan France, three million tonnes of non-recovered agro-food waste await the initiative each year, which will transform it. Meanwhile, the self-destruction of this biomass by composting releases methane into the atmosphere, while a considerable energy source and low pollution is irretrievably lost.

  Indeed, if we consider only the case of these three million tons of agro-food waste, on the one hand, and a kg of Bois des Villes can produce a minimum of 1 kWh, on the other hand their transformation could have produced 1.5 million tons of Bois des Villes, the combustion of which would have produced 750,000,000 kWh, that is, 750 gWh (gigawatt-hours).

  Reading this patent, one can also realize that the sources of supply of Bois des Villes are certainly not limited to food waste, since they also cover forest waste, green urban, agricultural, industrial waste. It is a source of energy of barely conceivable importance which remains to be treated and whose present patent postulates the valorization in calorific energy.

  Units of Measure Reminder Electricity consumption is measured in kilowatt-hours with multiples of: megawatt-hours (M) = I03 (thousands of kilowatt-hours) gigawatt-hours (G) = 106 (million kilowatts) -hours) 20 Terawatt-hours (T) = 109 (billion kilowatt-hours) Adaptation of City Wood to industrial use The opportunity for an increase in the role of biomass in electricity generation stems naturally from several imperatives worldwide 25 felt: a) The need to intensify the production of green fuels to meet the needs of French consumption without increasing CO2 emissions (with the consequent elimination of sulfur and methane emissions); (b) The possibility of substituting biomass for coal for peak generation in thermal power plants; (c) The development and testing of useful techniques and their export to other countries, especially those under development. -

  The production of bagasse being limited by that of sugar cane, Bois des Villes meets this expectation perfectly. Moreover, the closure of French coalmines (announced by the media in October 2003) will inevitably lead France to depend on imports of coals (United States, Poland, etc.) and to undergo the same type of diktat with the petroleum products as to fluctuations in purchase prices. The Bois des Villes can thus contribute to maintaining a relative energy independence of France (and of any other State which would develop its production on its territory).

  Indeed, the disappearance of French coal and the introduction of foreign coals at prices impossible to control could jeopardize the very large investments made in France. Bagasse being a product much healthier than the fossil energies, Bois des Villes does not postulate the replacement. On the contrary, the challenge for Bois des Villes is instead to gradually replace coal and oil, intervening, eventually, as the main fuel in their place, in the context of cogeneration.

  For the moment, a tandem charcoal bagasse gives full satisfaction to the thermal power station of the Moule (CTM) in Guadeloupe, the bagasse being supplied by the neighboring candy Gardel during the sugar cane season, from February to May. The interest of the industrialists in the energy valorization of the biomass can be evaluated, for example, to the fact that the power station of the Mold is the property with 44% of SIDEC, the group Charbonnages de France and 35% of EDF, the other shareholder being Air Liquide, either directly or through one of its subsidiaries. The plant comprises two boilers of 32 MW each, representing a total investment, at the time, of 700 million FF.

  The technologies used are very close to those already in use in the island of Reunion, in the Bois Rouge and Gol plants of the same SIDEC group. For these investors, the birth of a product likely to take the place of coal in the cocombustion process, at a cost price close to that of bagasse, is an opportunity not to be overlooked. -11 -

  A ton of raw vegetables of all kinds produces about 450 to 500 kg of Bois des Villes (compared to 320 kg of bagasse from a tonne of sugar cane). In 2000, production at the Centrale du Moule in La Guadeloupe was 415 GWh, including 75 GWh produced from bagasse. The Moule plant supplies one third of the electricity consumed in Guadeloupe and 70% of the electricity produced from renewable energy sources.

  The maximum production of CTM is estimated at 475 GWh. A 35-year contract guarantees CTM the repurchase of the electricity produced, at a rate set in 1996 at 45 cF l kWh for the first 380 GWh and 25 cF l kWh thereafter. 340 GWh (415-75) are therefore produced in Guadeloupe using low-sulfur coal. The gradual replacement of coal with another green fuel than bagasse therefore represents a major market whose objective, just for La Guadeloupe, is nothing less than the production of 81.93% of the electricity produced in France. Isle.

  But the use of bagasse, a free resource for CTM, is of course economically profitable. It is also effective in preserving the environment. It is worth remembering, in the face of this assessment, that a very worrying question arises for all plants using bagasse as an energy source: what is the future of sugar cane production in Guadeloupe and The meeting ? For biomass, the situation is obviously peculiar because of the permanent need for electricity producers to have high tonnage of bagasse. But these are derived from sugar cane crops, which has its limits. The bagasse market, and hence the power generation market in these two regions, is highly dependent on the maintenance or collapse of world sugar cane prices. The convulsions that once agitated this sector of the economy make it impossible to relegate this issue to secondary concerns.

  Industrial objectives Regarding electricity production, France's international commitments have recently taken an extremely concrete form: In 2010, it will have to produce 21% of its electricity consumption from renewable energies, compared with 15% today. today, with electricity consumption likely to have increased by 10 to 15% in the meantime. French consumption in 2001 was 457 TWh / year. According to the forecasts of the Ministry of Industry (Minefî) including an effort to control the electricity demand of 30 TWh / year in 2010 (equivalent to the production of 4 nuclear units!), The gross annual consumption will be in 2010 of 511 TWh. This forecast is based on an annual increase of 1.3%.

  Trend consumption in 2010: 511 TWh / year SER share 21 A) (1) 107 TWh / year Current SER share 74 TWh / year New RES production 33 TWh / year (1) RES = electricity from renewable sources One of the major concerns of defenders of the environment is that French electricity consumption will increase by at least 60 TWh / year by 2010, and that the market trend could be to provide this additional electricity from gas turbines, making use of to an energy with a high carbon content, even though gas is often misrepresented as clean energy. There is therefore a real risk that the electricity sector will once again severely burden France's carbon footprint, thereby reducing the room for maneuver on building, industry or transport in the fight against pollution. of the atmosphere.

  For future industrialists wishing to start production of Bois des Villes, it is interesting to note that the French law of February 10, 2000 instituted the obligation to purchase renewable electricity by EDF and non-Nationalized Distributors ( DNN), for installations of less than 12 MW.

  2864831 -13- As part of this obligation, a tariff was put in place by Ministerial Order. For cogeneration and biomass, these rates are as follows: ..................................... ..................

  .................................................. ........................ DT D: ......... DTD: Filière Duration of contracts Price range for new installations Cogeneration 12 years 6.1 to 9.15 cf / kWh depending on gas price, operating time and power Biomass 15 years 4.9 c lkWh + energy efficiency bonus between 0 and 1.2 c / kWh.

  NB: Energy efficiency bonus valorisation complementary to primary energy by cogeneration. The level of premium depends on the overall efficiency (electricity + heat) of the installation.

  The law of February 10, 2000 provides, moreover, the possibility for the Minister in charge of energy, to launch tenders if the investments envisaged by the Pluriannual Programming of the Investments are not realized spontaneously not the forces of the market. This provision should soon concern cogeneration from biomass, a sector for which the tariff is not at a sufficient height. These provisions show how it was opportune to start manufacturing the Bois des Villes.

  The Bois de Villles: a virtually inexhaustible energy and a market with huge potential The Bois des Villes is a constantly renewable energy. Since it is largely the direct product of human activities, it is linked to population growth, with its growth curve following closely that of demography. As such it can be considered inexhaustible and is a real alternative to both wood and fossil fuels. In Europe, if the Bois des Villes was to gradually replace the wood energy, it would ipso facto become the first renewable energy with 47.3 million toe (Tonne Equivalent Oil) or 54% and would arrive just in front of the hydraulics with 32%, incineration with 7%, geothermal energy with 3%, biofuels with 2%, and finally solar-wind with 2%.

  With 9.8 million toe (40 million M3 per year including 25 million M3 of forest origin and 15 million by-products of the timber industry and rural farms), France is the largest country in the world. Europe in the consumption of wood energy. In industry (800,000 toe consumed per 1,000 boiler rooms) and collective housing (9. 7 million toe consumed) France is the first in Europe. It is positioned Seme in the use of wood-energy by the communities (120,000 toe consumed).

  Thus, in France, the consumption of wood energy represents 4% of the global energy consumption.

  The irreversible current initiated by environmental concerns will inevitably lead to infinitely more respect for the wood once it has become an excuse to cut it for domestic or industrial heating purposes, as Bois des Villes can replace it very advantageously. The 9.8 million toe currently representing fuelwood consumption in France gives a very precise idea of the market share targeted by Bois des Villes, without prejudice to the actions that will be conducted, at the same time, towards oil users and of coal. It is therefore a gigantic market.

  4m3 environmental aspects of Bois des Villes save 1 toe. The ton of oil the use of which will have been avoided would, during its combustion, release CO2 into the atmosphere. The very rich ash of Bois des Villes (almost pure potash), once integrated into the soil of cultivated areas, will stimulate photosynthesis (CO2-consuming to make sugars necessary for the growth of plants, by oxidation of sugars during the respiration of plants).

  The stimulation of photosynthesis leads plants to capture significantly more CO2, which makes biologists say that photosynthesis converts carbon dioxide from the air into breathing biomass.

  On the other hand, CO2 will be emitted during the burning of Bois des Villes. However, if we take stock of what has been avoided (by abandoning fossil energy), what has been captured (through stimulation of photosynthesis) and what has been released (at the time of combustion) as CO2 in this cycle, one arrives at a zero balance and a total neutrality for the atmosphere.

  On the other hand, fossil energies (oil, coal, lignites) are infinitely more polluting. They contain a carbon stock that, incompletely burned, generates a very clear increase of CO2 in the atmosphere. Through its discharges of dust and ashes, but especially of nitrogen oxide and sulfur oxide, the exploitation of coal has become unsustainable, the negative ecological impact of coal has made its exploitation definitely indefensible.

  In France, as coal extraction is becoming more and more expensive, EDF prefers to invest in gas-fired plants, which are much less expensive. This measure is also justified by the gradual shutdown of French coal production, already divided by four over the last twenty years.

  The positive impact of Bois des Villes goes much further, because the manufacturing process makes it possible to integrate elements such as trees which can not be used in the furniture and construction industries, the branches resulting from pruning, wood chips and chips from carpentry and cabinetmaking or sawmills, bark, scrap wood (eg after dismantling concrete forms), sawdust, slabs, pallets, etc. However, if these elements are not recycled, they eventually rot on site or in a landfill, this time releasing methane into the atmosphere. Their energy recovery in Bois des Villes thus avoids this serious pollution.

  Economic aspects Economically, the Bois des Villes is much more interesting than fossil fuels. However, as for wood heating, these are the facilities that cost 1.5 times more. Nevertheless, financing solutions exist up to 50%. In France, the ADEA is in charge of advising and setting the amount of subsidies under the wood energy program 2000-2006.

  A reading of the legislation relating to it, nothing seems to prevent the use of these subsidies for a facility to burn Wood 10 Towns.

  In France, a specific regulation is applicable to wood boilers. It must be taken into consideration, since it is this type of boiler room which, without any adaptation, can be used to burn Town Wood. The height of the chimneys is fixed by law, and it depends on the power of the installation. For example, for a boiler of 10 to 15 MW, the height of the chimney must be greater than or equal to 19m. The speed of gas ejection is also imposed by law; it must be greater than or equal to 6m / s for biomass.

  The installation of a wood / biomass boiler with a power of less than 20 MW is subject to a simple declaration; On the other hand, the installation of a boiler of power higher than 20MW is subject to prior authorization.

  CHEMICAL COMPOSITION, COMBUSTION AND ASHES After drying and disappearing all its water, Bois des Villes consists of an organic fraction and a mineral fraction.

  The organic fraction The organic fraction is, like all organic matter, composed of 4 essential elements: C (carbon) for +/- 50%, H (hydrogen) for + 1-6%, O (oxygen) for + 1- 43 , 7% and N (nitrogen) for + 1 - 0.3%. This fraction is decisive for combustion because it gives Bois des Villes an energy quality that is completely comparable to that of wood, making it a high-performance fuel. Like wood, Bois des Villes is composed mainly of molecules of the type C4H603.

  But it should also be noted that in addition to the 43.7% oxygen included in its organic fraction, Bois des Villes traps a large quantity of oxygen during the process of grinding, mixing and kneading of its ligneous elements. . On drying, the water of the vegetable binder is replaced by an additional quantity of oxygen, which makes the Bois des Villes a fuel completely saturated with oxidizer.

  This is an essential feature that gives the product some of its innovative character. Its high oxygen content means that it requires much less O2 than fossil fuels during combustion. This principle of the presence of oxygen in the fuel to boost combustion is comparable to that of the diester, a vegetable oil (rapeseed and sunflower) which, added to the diesel fuel, provides oxygen, which improves combustion and reduces particulate emissions.

  In addition, the Bois des Villes contains almost no sulfur, which distinguishes it particularly from fossil fuels and makes it a product that is very respectful of the environment.

  Ashes: The mineral fraction, or ashes, can be determined in the laboratory by incineration of the fuel. The ashes resulting from combustion are constituted by the classic minerals, in all respects similar to those found in wood. This mineral fraction is relatively rich in calcium, very rich in potassium (it is largely almost pure potash) and has traces of magnesium, sodium, iron and silica.

  The ash content varies between 0.2% and 2% of the weight of dry matter, better than the Bagasse (slightly less than 3%) and especially coal (7 to 14%). Compared to coal, Bois des Villes gives an average of 10 times less ash. The problem of their evacuation on industrial sites is therefore reduced accordingly. And since this is one of a high quality fertilizer, reselling these ashes to farmers will help reduce the purchase price of Bois des Villes for industrial users. This is worth noting because coal is different.

  Ashes from coal combustion are grouped into three main families, silico-aluminous ash (resulting from the combustion of coal in pulverized coal boilers), cilico-calcic ash (produced by the combustion of coal in circulating Fluidized Bed boilers) and sulpho-calcic ash (from burning coal from Provence in pulverized coal boilers).

  Part of this ash is used for the manufacture of concrete, for the construction of roads or embankments and for the filling of cavities. Some, however, find no use. Storing a ton of such ash costs about one Euro. Nothing, therefore, benefits agriculture, and part of it costs us unnecessarily instead of bringing back. In addition, the outdoor storage of these ashes causes air pollution.

  Evaporated water: The energy quality of Bois des Villes requires a total absence of water. Originally, it is in a very variable quantity in the milled material, since several hundred components can be admitted in the manufacture, as long as the origin is vegetable. For example, for dry wood waste resulting from a 2nd transformation, the quantity of water is of the order of 20% maximum.

  On the other hand, for related sawmills and wood chips, it can reach 40 to 50%. In fruits and vegetables, it can represent up to 85 or even 90%. It is the significant shrinkage of material during the drying of very wet substances that self-compact the final product which requires, therefore, no compression, but a simple molding.

  Combustion: The oxidant is not only the oxygen contained in the ambient air, but also the one that the woody parts contain and, finally, the one that the manufacturing process allows to trap in the dough, around the woody parts trapped by the mixing . During combustion, a large amount of energy is released. The Bois des Villes heats as long as a log of wood and gives off the same heat. A briquette or a ball weighing between 300 g and 1 kg has a burning time of about 2 hours.

  Unlike wood, whose combustion is sometimes incomplete and lighting occasionally laborious, Bois des Villes lights very easily, does not smoke and is always consumed completely, making beautiful embers that make it suitable for domestic use (domestic heating , barbecue).

  Considering the almost complete combustion, the CO emissions are almost zero: C4H6O3 + 402 = 4 C + 3 H2O; this almost complete combustion requires an excess of oxygen which Bois des Villes has, unlike natural wood. As a result, a fraction of the nitrogen in wood and other wood products in this composite product combines with oxygen to form NO (x). This reaction releases a large amount of heat directly related to the carbon and hydrogen content of the woody parts of the mixture (maximum 40% of the mixture at the time of mixing).

COMPOSITION OF CITIES WOOD

CATEGORIES

  The products used fall into three categories, which represent the general appearance of the materials in question after they have been crushed or crushed: a) Fibrous materials a) Pasty substances b) Woody materials

DETAILS OF THESE CATEGORIES

  The following statements are not limiting and are only a few examples of the immense possibilities offered by biomass of plant origin in this field: a) FIBROUS MATERIALS They can be found in many plants, wild or cultivated.

  1. Wild plants Thistles, nettles, grasses (all species), reed leaves, bamboo leaves, lianas (all), all high-stemmed flowers such as carnations, daisies, or whose leaves contain long fibers such as irises, water lilies and all aquatic plants without distinction of kind, etc. , and all generally wild plants whose leaves or roots have a fibrous nature (straws, hay, tall grass, etc.).

  In general, almost all wild plants called weeds are fibrous in nature. They are therefore perfectly suitable for this manufacture. No fibrous wild plants, even those not stated here, will be excluded from the manufacture. All green waste resulting from the maintenance of embankments and ditches, riffles, irrigation canals, bodies of water, parks and public gardens, roadsides, sports fields, plantations, etc., are suitable, without any restriction. , the examples cited here being for the sake of guidance only.

  2. Cultivated plants Coconut fibers, pineapple waste, mango peels, leek leaves, celery stalks, cabbage stalks (all species), faded potato stems, beet leaves (all species), etc., and all generally cultivated plants of which the leaves or roots are fibrous in nature, such as all the fibrous vegetables and flowers of all origins found in market gardeners and florists, in greenhouses, fields or nurseries. No cultivated and fibrous plant, even if not stated here, will be excluded from manufacture, the examples given here being for the sake of guidance only.

  b) PASTY MATERIALS This is the appearance of the material after fine grinding. They are found in 2 areas 1. Cardboard All packaging cartons, regardless of origin, shape or consistency, flat or corrugated, single or double, thick or thin. 2. Fruits, vegetables and foodstuffs, compost and compost All products of any vegetable origin (fruits, vegetables, complex preparations), cooked (whatever the method) or raw, coffee grounds, tea waste, pasta (all), potatoes, sweet potatoes, various roots and tubers, various salads, fries, peelings of all vegetables and all fruits and vegetables and which are included, without exclusion or restriction, among the wastes green restaurants, cafes, snacks, truck-bars, hotels, pastry shops, bakeries, confectioneries, canteens, community kitchens (homes, clinics and hospitals, schools, nurseries, prisons), chip shops, food-producing fields, plantations, vineyards, breweries, greenhouses, fields, scraps of industrial food and non-food industries, including algae and aquatic plants, mushrooms, mosses and lichens, etc. In this group therefore come all fruits, vegetables and all mouth products generally any, without exclusion or restriction, may be reduced to pulp by grinding and regardless of their degree of freshness or mold. It also integrates the compost of dead leaves, whatever their source. No fruit or vegetable, any artisanal or plant-based food product that may be reduced to pulp, even if not stated here, will be excluded from manufacture, the examples given here being only as indications.

  (c) WOODY MATERIALS This refers to all products which have the nature of wood, without exclusion or restriction, and which, after crushing, will be incorporated in the final product.

For example:

  Wood planks from the dismantling of concrete forms, abandoned pallets, stumps and deadwood, hedge and shrub sizes, branches 22 - from tree pruning, light wood boxes such as fruit crates or intended for the transport of oysters and mussels, sawdust, fruit cores (from the coring of fruits before their processing in the canning industry or in the confiturière industry, or in confectionery, such as, for example, the kernels of dates, peaches, plums, cherries, apricots, lychees, olives, mangos), fruit bugs from all countries and nut shells of all species (European nuts, cashew, coconut, Brazil nuts, etc.) bugs almond kernels, etc. Spiny trees of all kinds also give very good results.

  No natural or industrially processed woody material, even if not stated here, will be excluded from manufacture, the examples given here being for the purpose of guidance only.

METHOD OF MANUFACTURE

  PREPARATION OF THREE GROUPS OF RAW MATERIALS Fibrous materials They are crushed, for example in a garden grinder, in order to obtain a fibrous pulp which will be used indifferently as it is or after drying. If necessary, water will be added to the product being mixed (later stage) if too dry products have been used.

  It should be noted that in the event of a shortage, the manufacture could do without these fibrous materials if need be. However, their presence in many products makes this hypothesis implausible, fibrous materials being unavoidable since we actually use all vegetable sources, without exception.

  In order to maintain a sufficient density of the product and to avoid the rapid combustion of a product that has become too light, the fibrous materials will not however exceed 10% of the volume of the total wet mass (to be evaluated before mixing). The grinding will be fine enough not to leave pieces, while releasing all the fibers whose size does not matter. -23 -

  The pasty materials They are crushed, for example in a garden grinder too, the teeth of the apparatus being adjusted to the tighter to obtain a fine grinding giving a mass more or less pasty, according to the degree of humidity of the products implemented. This coarse paste will be used indifferently as is or after drying. Immediate implementation is however recommended to avoid nuisances due to fermentation and insects. If necessary, water will be added to the product being mixed (later stage) if too dry products have been used.

  The coarse dough (pieces up to 2 cm in size) is transferred to a grinder-mixer as used in the manufacture of food for animals or industrial bakery. The trituration of the dough must give a product as fine as bread dough and having the same consistency.

  It should be noted that the use of cardboard at least 10% (and 50% maximum) of the total wet mass has the result of limiting or even preventing the fermentation of the whole, which neutralizes much of the nuisance due to possible odors. However, the presence of molds in the products to be kneaded is a positive element, because the agglomerating power of the products in process of decomposition has a favorable effect on the cohesion of the final product. This mold is subsequently neutralized by the pasteboard. The adhesive which is incorporated into the corrugated cardboard greatly increases the cohesion of the materials after drying.

  Ideally, pasty materials can represent 50% of the volume of the final product without affecting the calorific value or the cohesion of the product.

  Woody materials They are also ground in a garden grinder or in a coal crusher, to obtain pieces of 1 cm maximum side. If the material is too hard, a first passage in the mill, set to the widest, then a second passage, set to the tightest, may sometimes be necessary.

  To avoid harming the cohesion of the final product, the woody materials will not exceed 40% of the total mass to be kneaded before molding, which represents the ideal proportion.

  Presence of traces of fat It should be noted that urban green waste (60% of the total volume of urban waste) contains traces of fat. They come from the kitchen waste of restaurants, snacks, chip shops, and individuals. Remaining a very marginal phenomenon, minimal compared to the mass of treated cellulose, these fats do not denature the final product and contribute slightly to better combustion. These are cooking oils and fats, sauces, fat incorporated in pasta and preparations.

MIXING MATERIALS

  The pasty and fibrous products are kneaded intimately, then the woody materials are added to them and the whole is kneaded again respecting the aforementioned percentage limits for the three groups of materials. Starting from a pasty product having the consistency of the bread dough, after addition of fibrous and woody products, a more compact and malleable mixture is obtained, but having more body, easy to mold and not collapsing. . Humidity regulation is done: in case of excessive moisture, adding sawdust, potting soil, coffee grounds, ground compost (dead leaves passed to the tightest garden shredder) or crushed cardboard as finely as possible, or products of the bakery and the bakery.

  - in case of insufficient water, simply adding it.

  MOLDING AND DRYING THE FINAL PASTE

  Depending on the needs, the final dough can be shaped like lemon-sized balls (for barbecues), grapefruit (for open fires and industrial ovens), logs or briquettes, ( open fires and industrial ovens).

  - 25 - If the principles of manufacture have been respected, the products can be simply molded without being heated or compressed. Drying, which can accommodate a heat source (about 8 days drying at 30135 degrees centigrade) can also be done gradually without heat source (3 weeks at a temperature between 18 and 20 degrees centigrade). A good dryer can be organized easily and inexpensively in a corrugated iron tunnel painted out of matte black, so as to capture solar energy. Inside, the temperature will rise quickly to 60-62 and speed up the drying process (depending on the degree of sunshine).

  For drying, the moldings will be placed on corrugated cardboard plates, which absorbs a large part of the moisture, which greatly accelerates the evaporation of water and sap. Storage for drying can be done on stacked racks (rolling shelves). After surface drying, as soon as the exterior of the moldings is dry, the products can be stored in jute bags or strong paper and stacked, thus continuing their drying in a storage area, while releasing the dryer. For the industry, the bags can be thrown as they are in the ovens.

  For checking the moisture or drying rate, simply drill the center of a log or ball and insert a moisture tester such as horticulturists use.

  Materials excluded from manufacturing In order to respect the environment and not to harm the ozone layer, the following substances and products are formally excluded from the manufacturing process: - Newspapers and magazines Four-color advertising sheets - All substances or materials presenting traces of heavy metals Used industrial oils Plastics and related substances - All petroleum products All generally unspecified fuels - 26 - - All non-vegetal materials Manure and slurry Sludge from treatment plants Aspect of finished product and storage precautions Dried, this solid fuel is hard as wood, has virtually no odor, is very resistant to crushing, does not crumble and has a brown-gray appearance, the color may vary with nature of the supply. It is preferable to remove it from the action of humidity, but the drying restores all its calorific value, a possible mold in no way detrimental to combustion. Its nature can be investigated by xylophagous insects and rodents. Storage precautions will therefore be taken accordingly (deratting, insecticide spraying, fast bagging of completely dry materials).

  Briquetting It consists of a mechanical or thermomechanical transformation of the basic materials (residues) in order to reduce the volume, to increase the density and finally to give the shape of a briquette.

  Elements of the available technology: There are 3 types of technologies: The artisanal technology: It is the use of manual presses which develop a pressure of the order of 40 to 60 kg / cm3 corresponding to a densification effect of the order of 300 kglm3. The production capacity of manual presses is estimated between 60 and 80 kg / hour. There is a process developed by a Senegalese inventor (Mr. Baye Samba Lô) and patented with OAPI under the number 08717 of 13/02/1988. It makes it possible to obtain briquettes of combustible waste by compaction after grinding and mixing in a liquid (water).

  Semi-industrial technology: It includes the use of one or more hydraulic or mechanical presses (worms), which are often mobile units.

  - 27 - The production capacity of such a press is estimated between 800 and 900 kg of dry matter per day of 8 hours of work, which is clearly insufficient to cope with a large energy demand.

  Industrial technology: It includes fixed units of high capacity to meet important needs. A number of factors have a decisive influence on the quality of the product obtained. These include: pressure during pressing pressure time size and shape of desired briquettes physical properties of materials used water content temperature pre-treatments of these materials (grinding quality f mixing) .

  To obtain a product always uniform, always having the same aspect and the same calorific value is not as easy as it seems, considering the diversity of the materials used and the physical reactions sometimes very different from these. The following table provides a comparison of the advantages and disadvantages of each of these three types of technologies presented.

  Comparison of bricklaying technologies Types of technologies Advantages Disadvantages 35 Press briquetting Easily achievable locally. Requires the use of binder.

  Manual (at village level) On the environment, ne The quality of the briquette obtained poses no particular condition, is less than those produced does not require any training parti- tional mobile units or populations, invest-centralized ents least Mobile brickwork - equipment of lesser capacity; Technological level of the economy in terms of infrastructure requires equipment; user training - greater participation of the population in the realization.

  2864831 - 28 - Centralized Briquetting Units Achieved in areas where high investment energy density and sub-product formation is a problem. my ecological ones.

CONCLUSIONS

  In addition to its high calorific value, at least equal to that of wood, the Bois des Villes is a fuel that respects the environment, since with regard to the emissions of gases responsible for the greenhouse effect, it pollutes: - twelve fifteen times less than coal; - seven to twelve times less than heavy fuel oil or natural gas.

  By recycling green waste of urban, agro-food or forest origin, it avoids the dispersion of methane in the atmosphere.

  Its ash, composed mainly of potash, is a first-rate fertilizer that intensifies the photosynthesis of cultivated plants, greatly increasing the amount of CO2 captured by them and activating their growth. Ideally, the Bois des Villes ash should completely replace the compost that releases methane by providing plants with a much lower potash and irreparably ruining a superb source of energy.

  In addition, Bois des Villes is compatible with bagasse and can perfectly be used in the context of cogeneration electricity production. The Bois des Villes does not replace the bagasse, but complement it harmoniously.

  Estimates consider that, generally, the amount of non-reprocessed forest waste, on the one hand, and the quantity of agro-food waste abandoned to methanisation, on the other hand, is equivalent to the production of sugarcane. From these data, it is therefore easy to calculate the theoretically available tonnage in a given geographical area.

  In the case of the island of Reunion Island, chosen for the first implementation of Bois des Villes, the production of sugar cane is 2 million tons per year. The mass formed by forest waste + agro-food waste would therefore be around 2 million tonnes per year.

  For urban green waste, they are calculated as follows: Each inhabitant produces an average of 1 kg of household waste per day. About 60% of this waste is of plant origin and therefore combustible after treatment.

  With an annual average of 720,000 inhabitants, Reunion produces: 1 kg x 720,000 inhabitants. X 365 days X 60% = almost 157,680 tonnes of urban green waste recoverable.

  Together, these three sources yield approximately 2,157,680 tons of raw material to be treated, which would give about 1,079,000 tons of Bois des Villes (approximately half at best) for the entire island of Reunion. , assuming that it is properly and completely covered by an adequate mesh of waste collection systems, adapted to each source cited.

  Knowing that a kg of wood from the cities can produce a 1 kWh, the combustion of about 1.079.000 tons of this fuel would produce 1.079.000.000 kWh, in other words: 1.079 tWh (one billion kilowatt-hours, or a terawatt-hours). And that for the only small IIe of Reunion ...

  This simple approach finally makes it possible to realize that the world is wasting torrents of energy that would be very easy to channel.

  Does the Bois des Villes duplicate the incineration of household waste by local authorities? Incineration of household waste is by no means the most efficient way of producing energy. Indeed, the incineration of a ton of household garbage can produce only 300 to 500 kWh (EDF report and the - 30 - new energy 1998, available on the internet). On the other hand, the combustion of a ton of Bois des Villes produces 1,000 kWh. With daily disposal of a huge mass of household waste already sorted, the incinerators managed by the communities are naturally designated as the first skills in place to manufacture the Bois des Villes, if any.

  Other potential partners would only need to set up specific green waste collection channels in the forest and agri-food sectors so as not to compete with these communities while at the same time dealing with a huge tonnage.

  Who are the users of Bois des Villes? This product is particularly intended for industrial uses such as industrial furnaces (manufacture of glass, ceramics, cement, cooking food preparations for animals and humans, etc.), steam production (production of hot water for schools, clinics and hospitals, desalination of seawater by evaporation, production of electricity, steam for your sweets, etc.). Available in small briquettes, it can also be used for home heating in convectors originally designed for charcoal and wood, open fires, small barbecues for individuals and large grills catering, large collective boilers (such as of the city-school of Notre-Dame-des-Millières, France.

  What does the production of Bois des Villes cost? A study made by the ADEA and available on the Internet (La Biomasse: electricity production), shows production costs per kWh in the range of 0.07 to 0.11 on the basis of a cost of fuel of 50.00 per dry tonne.

  However, it must be taken into account that this study analyzed manufacturing methods implemented by private initiatives, with purchased biomass elements and dependent on fluctuations in raw material prices.

  Regarding the cost price in the case of private initiatives, it can be lowered by negotiating agreements avoiding the purchase of raw materials and by negotiating ad hoc interventions of cities and communities that will benefit from this fact. a particularly relevant solution to the problem of waste management.

  It is necessary to compare the cost price, with the unsecured stability, of the ton of low-sulfur coal which oscillates between 40 and 50 $ CIF, at the cost price always stable for the Wood of the Cities of approximately 12.50 per dry tonne. The latter is therefore an extremely attractive economic solution to the problem of replacing coal (and oil) with biomass.

  We can not say that this is excessive, because we must also compare this figure with another data. The destruction of a ton of waste by traditional means costs on average 25 (Science & Vie n 971, August 1998, p.107): 12.50 are devoted to recycling and disposal proper and 12.50 to transport.

  For communities that collect garbage, 60% of the plant waste they contain must be considered a waste that must be disposed of. Taking into account the subsidies received by these communities for this collection and destruction of waste, the manufacturing cost becomes nil, excluding transportation costs. If, on the other hand, transport costs (which might be moderate) are taken into account, we arrive at an amount of 12.50 per tonne transported. Manufacturing costs have been neutralized by subsidies, so it is ultimately this price that must be considered as the cost price of Bois des Villes If it is manufactured by a large community.

  Can Bois des Villes replace coal in the production of electricity? The 2000 report of the Court of Accounts in France leaves no doubt about the death of coal in general and French coal in particular. The situation of coal can be summarized as follows: - 32 - The exploitation of mines no longer responds to an economic logic (chronic and increasingly high losses); The closure of Charbonnages de France is planned for 2005 and their provisional maintenance is conceivable only for social reasons; Irreversible degradation of the operating conditions calls for the fastest possible closure of the sites; The support of the coal pact cost the public finances, for the period from 1995 to 2000, 741 FF per ton produced, which corresponds in other words to 350,000 FF per job maintained artificially.

  Beyond the notion of profitability of thermal power plants (almost the last customers of coal) and the very negative impact of coal on the environment, the simple respect of public finances makes it indefensible to continue the exploitation of this form. energy.

  The moment has naturally come for biomass, in the form of Bois des Villes, to take over from coal, both in industrial and private applications.

  Finally, in view of the French legislation specific to the field of waste treatment (laws of 15 July 1975 and 13 July 1992 enshrining the polluter pays principle), on the one hand, and on the other hand considering the implications of the French law of February 10, 2000 (obligation to purchase renewable electricity by EDF and non-Nationalized Distributors (DNN), for installations of less than 12 MW), we can conclude that all production of future French manufacturers of wood Cities is likely to find a buyer for the next decade, if not more.

  Reminder of the ideal proportions of the three groups of substances Pasty substances: 50% Fibrous materials: 10% Woody materials: 40%

Claims (5)

  1) Solid fuel, in the form of balls or briquettes, derived from the treatment of plant biomass, characterized in that the plants used are of all origins, without any exception, whether their source is terrestrial or aquatic, urban, forest, agri-food or industrial origin. It contains no chemical additives acting as binder, which consists only of vegetable matter which becomes pasty after grinding.   2) Solid fuel according to claim 1 characterized in that it self-compresses by a strong shrinkage of the material on drying, and is therefore content to be molded without compression or heating.   3) solid fuel according to claim 1 characterized in that in addition to the 43.7% oxygen included in its organic fraction, it first traps a large amount of additional oxygen during the grinding process, mixing and kneading of its woody elements to the binder paste, then by the fact that upon drying, the water of the binder is further replaced by an additional quantity of oxygen, which makes it a fuel totally saturated with oxidant. Its oxygen richness provides almost complete combustion that requires much less external O2 than for fossil fuels. The combustion gives: C4H6O3 + 402 = 4 C + 3 H2O. A fraction of the nitrogen of the wood and other wood products contained in this composite product combines with the excess oxygen to form NO (x). It is this reaction that releases a large amount of heat directly related to the carbon and hydrogen content that burns instead of being released into the atmosphere. The fuel contains almost no sulfur, which distinguishes it particularly from fossil fuels.   4) solid fuel according to claims 1 and 3 characterized in that it leaves after burning a fertilizer in the form of a very rich ash, consisting of almost pure potash, with a little calcium and with traces of magnesium, sodium, iron and silica. Its ash content varies between 0.2% and 2% of the weight of dry matter subjected to combustion. These ashes are not polluted by heavy metals and are therefore suitable as fertilizer for agriculture.   5) solid fuel according to claim 1 characterized in that in order to respect the environment, do not pollute the atmosphere and do not harm the ozone layer, the following substances and products are formally excluded from the manufacturing process : Newspapers Magazines Four-color advertising sheets Used industrial oils Plastics and related products All petroleum products All generally unspecified fuels.   All non-vegetal materials Manure and slurry - Sludge from sewage treatment plants