FR2810909A1 - Industrial waste recycling to make high calorific value fuel, removes metals before preparing comminuted carbonaceous waste mixture - Google Patents

Abstract

Metal scrap is sorted (10) from the waste. The waste is stored by categories. An intermediate composition (20) is prepared. It comprises mixed wood, paper, card, plastics, vegetable fibers and synthetic fibers. This is comminuted (16) to make a useful fuel.

Description

PROCESS FOR RECOVERING INDUSTRIAL WASTE AND

  HIGH CALORIFIC POWER COMPOSITION OBTAINED

  The present invention relates to a process for recovering industrial waste. The invention also covers the composition with high calorific value.

thus obtained.

  In the case of household waste, recycling with selective sorting is required and increasingly practiced by obligation because landfill is

  prohibited by lack of space on the one hand and by financial interest on the other.

  In fact, waste can be recovered in several ways.

  First of all, there is a selective sorting which ensures the removal of scrap by magnetic means and for non-magnetic metallic materials, metal detectors are used and manual removal is carried out. Likewise, plastic products such as packaging such as bottles for food liquids are separated. The organic matter and everything not removed is incinerated in ovens like those in cement factories. Such rotary ovens must be supplemented with carbonaceous materials, in particular coke, so as to raise the very low calorific value of organic materials which moreover contain a

certain percentage of water.

  Consequently, the financial balance sheet for the reprocessing of waste is burdened by

  The purchase of additional fossil materials.

  The object of the present invention is to provide a process for recovering industrial waste which makes it possible to obtain a composition with high calorific value which can be used alone as primary fuel. In this case, the high calorific value makes it possible to reach

  high temperatures and allows many applications.

  In addition, this composition can also be combined with materials with low calorific value and with difficult combustion to allow a

  combustion in the best conditions.

  We know that boilers with optimized operation are so-called fluidized bed boilers. Such boilers have a fuel in which an air flow circulates which ensures combustion on the one hand and also allows the suspension of the particles. Therefore, it is necessary to be able to have particles, of homogeneous size which moreover and not of pieces of disparate sizes and very variable densities. Indeed, the fluidized bed setting and the calculation as the distribution of the air flow would then be impossible. To this end, the process for recovering industrial waste according to the invention is characterized in that the following steps are implemented - sorting of the waste so as to remove the metallic materials, - preparation of an intermediate composition comprising a mixture of materials such as wood, paper / cardboard, plastics, plant or synthetic fibers, and - grinding of this intermediate composition to make it usable in

as fuel.

  An example of composition will be given later.

  Preferably, there is also provided a particle size included

between 25 and 50 mm.

  According to a very important improvement of the process according to the invention, cereal grains are added to this intermediate composition, in

proportions of 5 to 15%.

  The invention also covers the composition with high calorific value.

obtained.

  The present invention is now described in detail according to a particular, non-limiting embodiment, with reference to the attached drawing in which the single figure represents a view of a block diagram integrating the succession of

  steps of the method according to the present invention.

  According to the method of the present invention, the first step 10 consists in sorting industrial waste. This industrial waste includes all types of material except organic matter from household waste. This waste is stored in isolation for each category, this step is referenced 12. There are - magnetic or non-magnetic metals which must be systematically removed for the implementation of the method according to the present invention. During this main sorting, stones and other materials not

  incinerables such as ceramic or glass are removed.

  - wood, for example in the form of boxes, pallets, boards which cannot be used as it is because the pieces are generally too large

  important and above all not homogeneous.

  - cellulosic materials from paper and cardboard packaging.

  We can also find some vegetable or synthetic fibers in the case of fabrics, but these materials are found in small quantities in the case of

industrial waste concerned.

  - plastics that go from pipe or tube of any diameter and in different types of polymers. Please note that chlorinated plastics should only be stored if the subsequent incineration unit

  is equipped with a smoke treatment system with chlorine trapping.

  The process according to the present invention consists in preparing, from each of the types of waste, a basic composition, step 14 with the following proportions by weight - 40 to 60% of wood, - 10 to 30% of cardboard paper, - 2 to 15% of plastic material, and -2 to 15% of fabrics and other organic or synthetic fibers. Such a basic composition is introduced into a crusher which shreds the materials, this is step 16. Such a crusher is advantageously manufactured and marketed by the French company Phénix Industrie. Such a crusher has a drum with teeth which pass through a counter-grid and thus ensure the reduction of materials, be it fabrics, wood or plastic. The particle size obtained is in the range of 25 to 50 mm

to give an order of magnitude.

  This grinder also ensures mixing and homogenization of the

  materials simultaneously with grinding.

  In order to have a homogeneous material and above all in order to optimize the combustion in a subsequent fluidized bed, the particles pass through a grid.

  calibration, schematically shown in Figure 1 8.

  The composition thus obtained, called the intermediate composition, has an advantageous calorific value and sufficient to allow combustion without any other addition. However, for certain applications, this calorific value is still insufficient, so that the method according to the present invention provides for increasing this calorific value by adding

of cereals.

  Indeed, there are large quantities of cereal grains, in particular downgraded seeds, which cannot be used either in the food industry, often for reasons of quality and external presentation or size, or for the breeding of cattle for purely nutritional reasons. These grains are problematic because not only are they not valued, but they have to be disposed of, which is not easy. If you want to burn these grains directly, you absolutely must add a

  product of fossil origin, which comes back to the problem of household waste.

  Thus, in the major regions producing wheat, corn, sorghum barley or rapeseed, it is useful to propose a means of recovering these grains. The present process proposes to add to the intermediate composition

  an amount of 5 to 15% of cereal grains.

  To give an example, the following composition has a high calorific value since values of the order of 5,000 kcal / kg of combustible material are reached: - 40 to 60% of wood, - 10 to 30% of cardboard paper , 2 to 15% of plastic material, -2 to 15% of fabrics and other organic or synthetic fibers, and - 5 to 15% of cereal grains such as corn, wheat, barley, sorghum or rapeseed This addition is carried out directly in the intermediate composition 20, by a complementary hopper 22 and by passage through a mixer 24 which does not break the grains but simply ensures good

homogenization of the medium.

  These grains can also be added directly to the mill because the latter being of the tooth and counter-grid type, it does not occur

  no crushing and homogenization is obtained simultaneously.

  The final composition 26 thus obtained has an interesting calorific value as a fuel in its own right but also as a fuel

  make-up in fluidized bed boilers to maintain combustion.

Claims (9)

  1. Process for recovering industrial waste, characterized in that the following steps are implemented: - sorting (10) of the waste so as to remove the metallic materials, - storage (12) of the waste by category, - preparation (14) of an intermediate composition (20) comprising a mixture of materials such as wood, paper / cardboard, plastics, vegetable or synthetic fibers, and - grinding (16) of this intermediate composition (20) to give it back usable as fuel.   2. Method according to claim 1, characterized in that one ensures a   calibration (18) of the ground materials.   3. Method according to claim 1 or 2, characterized in that the particles of the intermediate composition have a size between 25 and mm. 4. Method according to claim 1, 2 or 3, characterized in that the percentage of the various compounds is as follows - 40 to 60% of wood, - 10 to 30% of cardboard paper, - 2 to 15% of plastic, and   -2 to 15% of fabrics and other organic or synthetic fibers.   5. Method according to one of the preceding claims, characterized in that   which are added to this intermediate composition (20) of cereal grains   to obtain a final composition (26).   6. Method according to claim 5, characterized in that the grains of   cereals are added in proportions of 5 to 15%.   7. Method according to claim 5 or 6, characterized in that the   cereals are chosen from corn, wheat, barley, sorghum.   8. Method according to one of claims 4 to 7, characterized in that   the grains are added after grinding and the whole is subjected to a mixing action to obtain a final composition (26) with high power   heat. 9. Composition with high calorific value obtained by the implementation of any one of claims 1 to 8, characterized in that the power   calorific value is around 5,000 kcal / kg.