NL2001501C2 - Synthetic building material e.g. brick, producing method, involves heating mixture of fly ash, sewage sludge, bottom ash, biomass materials, incineration ash, wood fines and waste ash with energy to specific temperature - Google Patents

Abstract

The method involves heating mixture of fly ash, sewage sludge, bottom ash, biomass materials, incineration ash, wood fines and waste ash with an energy i.e. refuse-derived-fuel (RDF), to a temperature of 1000-1500 degree centigrade, where the energy is utilized as pellets and fluff. Combustion gases are discharged into a furnace for production of a building material e.g. brick, where weight ratio of the energy and the mixture is about 6 mega-joules per kilo-gram. An independent claim is also included for a building material.

Description

NL 47,597-KP / ar

Method for manufacturing energy and synthetic building materials, such as basalt, gravel, bricks, tiles, etc. and similar materials from high-calorific waste and mineral residues.

Such a method, known from Dutch patent 1 028 908 in the name of applicant DHV Ruimte en Mobiliteit B.V. with filing date April 29, 2005, is part of this application.

According to the known method, bricks are made from a mixture of dredging spoil and granulite sludge by baking this mixture in a conventional brick oven at 1040 to 1080 ° C.

For baking, use was made of mainly 10 fossil fuels such as natural gas, mineral oil and so on.

As these fuels become increasingly scarce and therefore increase in price, the known process becomes less attractive in economic terms.

The invention now has for its object to provide a method for the manufacture of synthetic building materials, such as basalt, gravel, bricks, tiles, etc., wherein the increasingly expensive fossil fuels such as natural gas as energy carrier are replaced by a fuel which is cheaper and can be extracted. from high calorific waste or bio-20 mass.

To this end, the invention provides a method for manufacturing energy and synthetic building materials, such as basalt, gravel, brick, tiles, etc., wherein a mixture of fly ash, sewage sludge, bottom ash, biomass conversion ash, gasification ash, incineration ash, wood fines, waste ash, and such combustion products are heated together with an energy carrier, which materials are continuously led into a melting / gasifying oven and heated therein to a temperature of 1000-1500 ° C, the molten materials being discharged separately as the resulting combustion gases. The materials are preferably heated to 1300-1400 ° C.

According to the present invention, a contribution is made to the environmental problems associated with a large surplus of high calorific waste, RDF (paper and plastic), high landfill and incineration costs.

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Due to the increase in the high costs of fossil fuels, there is now an increasing demand for energy from non-fossil fuels.

Moreover, the invention addresses the problems associated with an increase in dumping bans for (difficult) waste in the EU. According to the present invention, from waste streams such as fly ash, sludge, bottom ash, biomass conversion ash, gasification ash, combustion ash, wood fines, waste ash on the one hand and RDF as energy carrier on the other, valuable products are obtained such as building materials on the one hand and fuel gases on the other hand, for all kinds of industrial ovens.

During a melting process, the material in the furnace is brought to such a temperature that the mineral components are melted. The energy (heat) required for this is supplied by the energy carrier and other organic material. With the molten material obtained in this process. basalt with properties such that any environmentally harmful components are immobilized in the basalt or otherwise removed so that they can no longer cause damage to the environment.

Synthetic basalt is microcrystalline, does not leach and complies with current building materials decisions.

Surprisingly, it has been found that under reducing conditions (melting gasification) the total energy efficiency is certainly 85%, of which 60% of the energy content is in the fuel gas formed.

It is surprising that according to the present method extremely useful valuable building materials such as basalt can be obtained from worthless residual flows.

It is noted that there is a great need for basalt for all kinds of applications such as, for example, for reinforcing dikes, paving and so on.

It is further noted that the melt (also referred to as slag) must satisfy a number of properties, namely, viscosity, liquidus temperature, the thermodynamic properties and crystallization behavior.

It is important that the slag has a certain viscosity at the melting temperature. This is important on the one hand because of the tapability of the slag, which is hampered by a too high viscosity, and, on the other hand, because of the possible deterioration of the furnace lining in the case of a very low viscosity. The slag can be seen as a three-dimensional silica network. Due to this three-dimensional structure, slags with a high silica content have a very high viscosity. This network is modified by the presence of other components.

As more binding in the network is broken, the viscosity decreases. The extent to which silica bonds are broken depends on the added components. A strongly basic "components" such as CaO and MgO break the network more open than an equivalent amount of, for example, Al 2 O 3. The latter will often, depending on the added components, even strengthen the network and thereby increase the slag viscosity. The slag viscosity is furthermore very strongly influenced by the temperature. Therefore, viscosity estimation for slag gives the possibility to indicate a lower operating temperature limit required from a viscosity point of view. This is based on a temperature of approximately 1400 ° C. From the point of view of a well-manageable slag, a maximum viscosity of about 10 to 30 Pa.s is desired. Too low a viscosity <about 1 Pa.s is undesirable because of an increased risk of attacking the refractory inner liner of the oven.

The liquidus temperature of a snail is that temperature at which the snail is completely melted. This must be sufficiently low to prevent deposits in the furnace, and to ensure a homogeneous product, the slag must have been completely melted, for this purpose the liquidus temperature must be at least about 50 ° C below the operating temperature. The calculated liquidus temperature must therefore be a maximum of 1350 ° C.

The thermodynamic properties of the slag. In this context, particular consideration should be given to the activity coefficients of the heavy metals (for example, zinc), primarily to be able to assess whether volatilization of the various polluting components will suffice to produce a leachable product (not leachable defined as compliance with the building decree). category I or IA). In addition, it is important to assess whether a liquid metal phase (especially iron) could arise. In general, the levels of heavy metals in the current considered are relatively low.

Crystallization behavior. This is important for the properties of the product obtained, in particular the environmental hygiene (leachability) and the building physical properties. In the first instance, a crystallized product is assumed.

It is noted that the preconditions for a suitable feed stream (raw material according to the present invention) are as follows:

The feed stream (raw material) must contain sufficient calorific value to reach the desired melting temperature, i.e. at least 6 MJ / kg, while the composition of the mineral part of the mixture must be such that the properties of the resulting slag lie in the desired range with respect to melting temperature, viscosity (basicity) and crystal structure after cooling.

- The liquidus temperature may not exceed 1350 ° C.

- Viscosity must be between 1 and 30 Pa.s and 15 - The basicity must be at least 0.6.

It has been found that single streams based on slag properties with regard to crystallization, it is to be expected that sewage sludge and a slightly lesser extent of biomass incineration ash and wood fines as mono streams are already reasonably meltable if they are tested against the requirements of a good melt. For burned-out gasification ash and waste ash, it can be expected that they can only be melted properly in combination with other streams.

With regard to slag properties and hence the operability of a melting plant, an improvement can be achieved by mixing streams with different properties.

With mixtures of the given materials, an optimum composition can be achieved, the main condition being that they have less than 65% as wood gasification ash. Wood gasification ash, can be mixed with sewage sludge to a maximum content of about 50% wood gasification ash in the mixture.

Waste ash can also be mixed with sewage sludge up to a maximum level of 70%.

It is noted that part of the material disappears to the gas phase. Cl, Cd, Zn and Pb and many other metals are not found in the solid phase (melt). However, these components often already existed in small amounts in the fuel or had largely disappeared from the starting material during the thermal treatment at a temperature of about 1100 to 1150 ° C. There are traces of 40 from K and Na. A measurable amount of Cr, Mn or Zn can also be found in some phases. It is striking that almost all phosphate remains behind, bound to Ca and Mg. The consequence of this is that the solid substance (basalt) is nice and clean, but that there can be a fair amount of problem elements in the flue gas. These elements will precipitate in large quantities upon cooling, because they are also driven into the gas phase only by heating and not by conversion. This means that flue gas cleaning is required.

The material flows (with the exception of the amount of slag) do not differ greatly in both reducing and oxidising operations. All this means that the pure installation could be used in both (oxidizing and reducing) ways, making a very flexible business operation possible.

The fuel gases formed can be used instead of expensive fossil fuels such as natural gas for the production of building materials in conventional brick ovens for further production of basalt, gravel and so on.

As is known, there are various furnaces, however, according to the invention, for example, an entrained flow gasifier 20 is used. This is a reactor with the top injection of powdered or gaseous energy carrier, oxygen and steam.

RDF is preferably used as the energy carrier.

RDF (Refuse Derived Fuel) as an energy carrier is extracted from waste. In the past, waste was simply dumped, against which there are now many objections from an environmental point of view. Ever-growing awareness of the negative environmental impacts of landfilling waste have led to alternative methods of waste processing.

It is noted that many constituents in waste (domestic, gray and industrial waste) have a high calorific value, making them very suitable as an energy carrier. The fuel from waste (Refuse Derived Fuel (RDF)) can be used as a (replacement) fuel for power stations and various industrial processes. The use of RDF as an energy carrier instead of expensive fossil fuels such as natural gas, oil and so on, has two advantages.

Firstly, it results in a considerable reduction in the amount of waste dumped and, secondly, the use of expensive fossil fuels is greatly reduced. In addition to combustible components (paper, cardboard, plastic, rubber and wood residues), waste also contains non-combustible 6 components (sand, stone, ceramics, ferrous and non-ferrous metals), so-called inert materials, and wet-organic material. (food waste, garden waste). Wet organic and inert materials are not suitable for use as RDF.

RDF can be used as energy carrier in the form of RDF fluff or RDF pellets.

The term "RDF-fluff" stands for high calorific components that are sorted from waste and then dried. Fluff is a dry, flammable and very airy material 10 (50-80 kg / m3). In order to be able to transport or store fluff effectively, it can be pressed into bales.

RDF-fluff can also be made compact by means of pelletizing to deliver RDF fuel pellets. Such fuel pellets are thickened, sturdy and have a substantially constant size, making it economically feasible to transport the RDF material over large distances to the destination. Such RDF pellets have the advantage that they remain intact for some time, making them suitable for fluidized bed gasification and as a co-fuel in certain power plants.

As already mentioned in the description, the RDF can be used in the form of pellets or "fluff", the use of pellets being preferred because of the better transportability, compactness and so on.

Moreover, RDF pellets are particularly suitable for use in a fluidized bed gasification furnace.

It is advantageous according to the present invention if the weight ratio of RDF and added mixture is such that the calorific value of the mixture is at least 6 MJ / kg.

With good results, a mixture according to the invention is used whose components satisfy the following properties:

Property__Tliq (° C) Viscosity (Pa.s) Basicity (-)

Optimal range <1350 1-30> 0.6

Sewage sludge 1311 2.8 0.65

Gasification ash 1550 90 0.54

Combustion ash 1391 3.1 0.61

Wood fins 1376 1.8 0.64

Waste ash 1512 6.5 0.67 RDF__ 0.5__ 7

Finally, the invention relates to building materials, such as basalt, gravel, bricks, tiles, etc., obtained from the molten, glazed, baked or sintered materials produced in the process according to the invention.

The invention will be explained in more detail below with reference to the accompanying Figure and examples.

In the Figure, A represents the method according to the invention and B the use of the flue gases formed in the method A in the conventional furnaces for the production of building materials.

A illustrates a melting gasifier. The principle of the melting process is that a mixture of RDF (high calorific organic waste / biomass) and mineral waste (fly ash, bottom ash, dredging sludge, etc.) at a temperature of 1000-1500 ° C, preferably 1300-1400 ° C is brought in which the mineral components are melted. The required energy (heat) is preferably supplied by the energy carrier RDF, the organic part of the mixture. The desired product, a synthetic basalt, has such properties that environmentally harmful components are immobilized or removed and can no longer cause damage.

B illustrates a sub-process that consists of processing the gases from the melting gasifier. The flue gases obtained are high-calorific gases that can be used as synthesis gas for the chemical industry, as an energy carrier for generating heat and electricity or as a fuel gas for processing mineral residues via ceramic processes such as sintering and glazing and melting processes. In the present case, the sub-process consists of the generation of heat, which is used for the melting gasifier and for the production of ceramic products from mineral residues. Environmentally harmful components are immobilized in the ceramic products or removed via the flue gases. Sub-process A and B can have a joint flue gas cleaning for this purpose.

This method for the ceramic processing of mineral residues is known from the aforementioned Dutch patent 1 028 908 in the name of applicant DHV Ruimte en Mobiliteit B.V. with submission date April 29, 2005.

It goes without saying that the present invention 40 is not limited to the Figure discussed above and the examples below.

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Example 1

Melting gasification of a mixture of dried sewage sludge, biomass incineration and gasification ash and ash from a paper recycling residue (Source: Melting biomass residual streams and waste into (sustainable) energy and raw materials. A study 5 into possible fuel mixtures and a smelter preliminary design. Boersma, JR Pels, ABJ Oudhuis, JP Lotens, ECN-C - 06-013).

Example 2

Pilot remediation and thermic immobilization or sediment-10 ments of New Merwede River. (Source: L.A. van der Kooij, DHV Environment and Infrastructure BV, P.O.Box 1076, 3800 BB Amersfoort)

Example 3

Production of bricks from dredged material and granulated sludge by baking this mixture in a brick oven at 1040 - 1080 ° C (Source: Dutch patent 1,028,908 in the name of applicant DHV Ruimte en Mobiliteit BV with filing date April 29, 2005).

Claims (10)

Method for manufacturing energy and synthetic building materials, such as basalt, gravel, brick, tiles, etc., characterized in that a mixture of fly ash, sewage sludge, bottom ash, biomass conversion ash, gasification ash, incineration ash, wood fins, waste ash and similar combustion products is heated together with an energy carrier, which materials are continuously led into a melting / gasifying furnace and heated therein to a temperature of 1000-1500 ° C, the molten materials being discharged separately as the resulting fuel gases. Method according to claim 1, characterized in that the materials are heated to 1300-1400 ° C. 3. A method according to claim 1 or 2, characterized in that the fuel gases are discharged to an oven for the production of building materials such as basalt, brick, gravel, etc., or to a power plant. The method of claims 1-3, characterized in that the melting / gasifying furnace is an entrained flow gasifier. 5. Method according to claims 1-4, characterized in that RDF is used as the energy carrier. Method according to claim 5, characterized in that RDF is used in the form of pellets. Method according to claim 5, characterized in that RDF is used in the form of "fluff". A method according to claims 1-7, characterized in that the weight ratio of RDF and added mixture is such that the calorific value of the mixture is at least 6 MJ / kg. 9. Method according to claims 1-8, characterized in that a mixture is used whose components satisfy the following properties: Property _Tliq (° C) Viscosity (Pa.s) Basicity (-) Optimal range <1350 1-30 > 0.6 Sewage sludge 1311 2.8 0.65 Gasification ash 1550 90 0. 54 Incineration ash 1391 3.1 0.61 Wood fins 1376 1.8 0.64 Waste ash 1512 6.5 0.67 RDF__ 0.5__ 10. Building materials, such as basalt, gravel, bricks, etc., obtained from the molten, glazed, baked or sintered materials formed in the process according to claims 1-9.