CH688193A5 - Process and installation of biogas and composting integrated. - Google Patents

Description

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CH 688 193 A5

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Description

The present invention relates to a method and its implementation, providing the conditions for synergistic integration of the biological processes of anaerobic digestion and composting, with a view to their application in the field of treatment and recycling of waste biomass, in particular of the organic fraction of urban waste sorted at source and collected selectively.

An area in which the processes mentioned have been or are most of the time operated separately, sometimes consecutively, but never in a parallel and interractive manner, within the meaning of the present claims.

The present process applies equally to continuous or semi-continuous anaerobic digestion and so-called accelerated composting techniques, for example: in silos, silo-corridors or rotary bioreactors.

Its implementation leads to a significant improvement in the biological and energy yields of the techniques mentioned, the integration of which simultaneously allows the extension of their processing capacity to the full spectrum of the biomass of waste, and the minimization, even the elimination of their respective releases to the environment.

- Claims 1 to 3 respectively establish the general concept, the main in-terractive factors and the associative condition of the processing routes which determine the invention.

- The general diagram of the process (fig. 1) represents a pre-treatment unit (1) feeding a line of biomethanisation (2) and composting (3) with waste (4).

- The liquid effluent and the residual biomethanisation sludge (5) are injected into the composting line, while the water or other liquid (6) necessary for the balance of the system, is returned to it at the level of the line anaerobic digestion whose products are respectively biogas (7), which will provide all or part of the process energy, and the solid and stabilized fraction of its effluent (8) whose intrinsic properties make it possible to envisage recovery in the food industry.

- If the biomethanization line stops, its effluent injected into the composting line can be temporarily replaced by water, thus avoiding interrupting the production of compost

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- Said diagram finally shows that the undesirable (10) are eliminated at the start of the process, at the level of the pretreatment unit, which fulfills in this respect a general protection function of the installations.

Through a specially designed pre-treatment and routing unit, the claimed process responds flexibly to the uncertainty that characterizes the qualitative distribution of waste over time, by allowing the largest instantaneous transfer of compatible materials from one treatment line to the other, thus making the best use of their complementarities, their complementarities and their respective carrying capacities.

In addition, this unit has a special arrangement for adapting to the predominant nature of the waste present, which can be alternately woody and coarse or fine and wet, by reversing the order of engagement of its packaging members.

- Claims 4 and 5 respectively establish the concept and the functional potentialities of the pretreatment unit defined in the present invention.

- Figs. 2 and 2a show schematically and without limitation the two operational variants characterized by a different order of engagement of the classification (1.1) and particle size reduction (1.2) bodies of said unit. These figures also show how the pre-treatment by-products constituted by the juices (1.3) and the materials with low ganulometry (1.4) are preferably separated and routed, preferably referred to biomethanization because of their absence of structure, as well as the manner whose residual solid fraction (1.5) is partly routed directly to composting and partly recycled in a retroactive loop (1.6) allowing to act on the distribution of flows.

- Buffer storage (1.7) may be necessary in various places, depending on the conditions encountered in the supply of waste and according to the particularities presented by the specific techniques of anaerobic digestion and composting involved.

According to the claimed process, the conditions for the interactive management of the two processing lines are achieved by the direct cooperation of the pre-processing unit described, with two separate functional sub-assemblies called transfer modules, and arranged at the top of each. processing lines.

The purpose of these modules is to manage the interconnectivity of said treatment lines and to create the necessary interfaces between the pre-treatment unit and the specific biomethanation and composting systems implemented.

Claims 6 and 7 define said transfer modules and their main functions.

Fig. 1 also shows how the relationship is established between the preprocessing unit and each of the technical processes, via these modules, the first of which (2.i) initializes one or more bioreactors (2.2) of the line of biomethanization and performs the interactivity of said line with that of composting by means of a second module (3.1), which in turn initiates the specific process of composting (3.2) attached to this last line.

By the functions it brings together, the transfer module of the biomethanization line is the main seat of the biological and technical management of the claimed process as well as the place of its energy management.

To reduce the influence of the heterogeneity of the waste on the conditions of anaerobic digestion, a conditioning step precedes the introduction5

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tion of materials in the bioreactor, with the double effect of normalizing them and isolating a residual liquid fraction.

Likewise for the extraction of digested materials, one or more conditioning steps also make it possible to isolate the liquid fraction and treat the solid residue separately.

According to this conception, the biological, hydraulic and physical regulations of the whole process are operated through the differential - and integrated - management of the generated liquid fractions, which are also the heat transfer fluids which transfer to the incoming materials the thermal energies contained in the outgoing materials. and dissipated by the previously mentioned packaging members.

- Claim 8 specifies and lists the functions specifically characterizing the transfer module of the biomethanization line.

- Fig. 3 shows a non-limiting diagram of said module showing the relationships established between its respective bodies for conditioning and introducing materials in solid (2.11) and liquid (2.12) forms into the bioreactor (s), as well as extraction and conditioning of digested materials (2.13), the fraction of which is not recycled into the bioreactor by the retroactive loop (2.14) is conveyed to the composting line after having transferred its heat to the incoming materials in an exchanger (2.15).

The figure also shows that additives (2.16) can be dosed in the module to act on the biochemical course of the process or complete the formula of its products.

Although the invention described applies to all kinds of waste and combination of organic waste, it has a privileged application in the urban context insofar as, unlike composting and anaerobic digestion envisaged individually, it can treat locally, completely and economically all the organic fraction generated.

Indeed, through the play of complementarities developed between the two processes, it is no longer necessary to look outside the waste collection departments for co-substrates which would generate, in the event of an exclusive use of composting in urban areas, an increase in the total mass of waste to be treated on the order of a quarter to a third, accompanied by the corresponding transport costs.

- Claims 9 and 10 respectively establish the characteristics preferably attached to the pre-processing and routing unit as well as to the transfer modules of each of the processing lines, in the application and the implementation of the method for the treatment and recycling of the organic fraction of urban waste sorted at source and collected selectively.

Claims (1)

Claims 1. Process for the treatment and recycling of waste biomass, characterized in that the waste is treated in parallel and interactively, on the one hand in a biomethanation treatment line and on the other hand in a composting treatment, between which the waste is distributed thanks to the help of a pre-treatment and routing device which also has the means to eliminate unwanted or non-compliant materials. 2. Method according to claim 1, characterized in that the liquid effluent and the residual biomethanisation sludge are introduced into the composting line, so as to compensate for its losses by evaporation while stimulating its microbiology, and that the water or any other liquid necessary for the system are returned to it at the level of the anaerobic digestion line. 3. Installation intended for the implementation of the method according to claim 1, characterized in that the pre-treatment device (1) constitutes a separate functional unit having, in addition to the means (10) for eliminating undesirable matter, two at least, classification and particle size reduction organs: the first (1.1) having the function of filtering the materials of lower granulometry as well as the juices and of routing them towards the line (2) of biomethanisation, and the second ( 1.2) to standardize the particle size of the residual materials. 4. Installation for implementing the method according to claim 2, characterized in that the biomethanisation line (2) and the composting line (3) are connected by a connection (5) with optional operation, capable of driving the liquid effluent and residual sludge from the biomethanisation line (2) and bring them to a transfer module (3.1) of the materials to be composted. 5. Installation according to claims 3 and 4, characterized in that the pre-treatment device (1) has means for conveying the materials not eliminated by said means (10) of elimination, to their treatment lines and to regulate the degrees of conditioning and distribution, including over time, of these materials, in particular by bringing into play, alone or in combination, means: a) partial or total recirculation (1.6) of the materials between the classification and size reduction bodies mentioned; b) modification of the granulometric parameters of said organs (1.2); c) inversion of the order of intervention of the said bodies; d) using buffer storage (1.7). 6. Installation according to claim 3, characterized in that the biomethanization line (2) comprises at least one bioreactor of the continuous or semi-continuous type (2.2), and a specific functional sub-assembly called the transfer module (2.1), bringing together all the feed functions of the digester (s) and comprising means (5; 2.13) for interrelating the said biomethanisation line with that of composting (3). 5 10 15 20 25 30 35 40 45 50 55 60 65 3 5 CH 688 193 A5 7. Installation according to claim 4, characterized in that said transfer module (3.1) of the materials to be composted is disposed upstream of a unit (3.2) of final composting and is arranged so as to incorporate the effluents from the biomethanization to the materials to be composted and to initiate fermentation, this process being led to the stage of complete hygienization. 8. Installation according to claim 6, characterized in that said transfer module (2.1) comprises at least members: a) separate conditioning and introduction (2.11, 2.12) of the solid and liquid fractions of the substrate into the bioreactor (s) (2.2); b) extraction, separation of the solid and liquid phases, and conditioning and transfer (2.13) of the digested materials; c) transfer (2.15) to the incoming materials, heat from the outgoing materials and the functioning of the aforementioned organs; as well as means (2.16) of introducing additional additive substances into the material flows, in particular to correct the progress of the treatment process or the formula of its products. 9. Installation according to claims 7 and 8 for the joint treatment of food and plant waste from so-called selective or assimilated collections, characterized in that the treatment members (1) of this waste include a calendering or sieving device with adjustable or interchangeable hopper, as well as a grinding device also provided with a means for adjusting its particle size, these devices being combined so that the introduction of waste is possible by one way or the other depending on their nature initial and that their packaging can be easily adjusted according to the needs of the process. 10. Installation according to claims 7 and 8, for the joint treatment of food and plant waste, characterized in that: the operations of packaging and introduction of the materials are carried out simultaneously by a mechanical extrusion device comprising screws, knives, dies, the extraction and stabilization of the solid effluent are carried out successively by a press and a grader, both with screws, possibly arranged on the same axis, the management of the liquid fractions is ensured by a metering pump, and the incorporation of liquid effluents and sludge into the materials to be composted is ensured by a section of rotary drum specially adapted to this function. 5 10 15 20 25 30 35 40 45 50 55 60 65 4