WO2013079062A1

WO2013079062A1 - Device for the hydrothermal carbonization of biomass

Info

Publication number: WO2013079062A1
Application number: PCT/DE2012/100365
Authority: WO
Inventors: Thomas Reichhart
Original assignee: Thomas Reichhart
Priority date: 2011-12-02
Filing date: 2012-11-30
Publication date: 2013-06-06
Also published as: DE102011055987A1

Abstract

The invention relates to a device for the hydrothermal carbonization of biomass, comprising a reactor (5, 5') having a reactor wall, in which the biomass is dehydrated and carbonized, and wherein the reactor comprises on the inner side of the reactor wall at least in sections a coating that prevents the biomass from adhering.

Description

Device for the hydrothermal carbonization of biomass

The invention relates to a device for hydrothermal carbonization of biomass according to the preamble of patent claim 1.

For the purposes of the invention, biomass means all renewable raw materials, i. vegetable biomass and derived animal biomass and their metabolites understood, so for example, green waste, wood chips, plant and plant residues, straw, silage,

Residues from agriculture, paper or sewage sludge etc ..

Devices for the hydrothermal carbonization of biomass are already known from the prior art. The hydrothermal carbonization simulates the natural production process of lignite. In this case, biomass is dehydrated and carbonated as starting material in a reactor under a pressure in the range between 10 bar and 35 bar and temperatures in the range between 180 ° C and 240 ° C, at the reactor outlet then a coal sludge can be removed. In this coal sludge coal particles are contained by a drying and / or

Drainage process can be removed from the coal sludge. These obtained after the drying and / or dewatering process

Coal particles give off a coal dust, almost the entire

Contains carbon of the processed biomass and has a calorific value substantially equal to the calorific value of fossil brown coal. The hydrothermal carbonization is an exothermic reaction, ie during the dehydration and carbonation process, reaction energy is released in the form of heat A disadvantage of the process is that biomass or during the process of hydrothermal carbonization resulting

Incorporation of intermediates on the wall of the reactor and thereby adjusts itself over time, an undesirable encrustation of the reactor wall. This encrustation must be removed by hand after a certain time, resulting in a complete decommissioning of the entire plant and a

complete emptying of the reactor conditionally

Based on this, it is an object of the invention to provide a device for the hydrothermal carbonization of biomass, the one

Incorporation of biomass or intermediates effectively prevented. The task is based on the generic term of the independent

Patent claim 1 solved by the characterizing features. The essential aspect of the device according to the invention, which has a reactor with a reactor wall in which the biomass is dehydrated and carbonized, is that the reactor at least in sections on the inside of the reactor wall a

Coating, the adhesion of the biomass or the

Process intermediates prevented. In this case, the coating has the effect that the reactor wall has improved sliding properties in comparison to the uncoated state, thereby preventing adhesion. The reactor wall may in this case be coated, in particular, on the areas in which biomass or process intermediates are located during the carbonization process due to gravity. This is especially the lower and middle region of the reactor. Preferably, however, the entire reactor wall is coated on the inside.

In a preferred embodiment, the reactor contains in its interior a heat exchanger, which is designed for the passage of flue gases or steam This heat exchanger, the Temperature control of the reactor contents, also has a coating which prevents adhesion of the biomass. Especially at

Heat exchangers are required to be installed at the points where heat exchange takes place, i. For example, the heat exchanger tubes, no incrustations, since thereby the heat exchange is deteriorated. The coating of the heat exchanger with a material with high sliding properties effectively prevents this adhesion.

Particularly preferably, all elements contained in the reactor are provided with the coating. Such other elements can

For example, baffles, piping, etc. be. As a result, the adhesion of biomass and / or intermediate products to all elements provided in the interior of the reactor can be prevented. In a further preferred exemplary embodiment is a

Preheating provided for heating the biomass supplied to the reactor, which is bounded by a wall at least peripherally and underside. The preheating device is preferably a pressure-tight closable chamber. The wall of the preheating device is preferably likewise coated on the inside, so that adhesion of the biomass can also be effectively prevented there.

Particularly preferably, the coating is formed by a material layer of polytetrafluoroethylene (PTFE) formed polytetrafluoroethylene

excellent sliding properties and is resistant to aggressive chemicals or solvents. Furthermore, polytetrafluoroethylene is permanently heat resistant up to 260 ° C, so that required for hydrothermal carbonization temperatures between 180 ° C and 240 ° C, the coating does not destroy or damage. Particularly preferably, the coating has a thickness of 15-20 .mu.m. In this layer thickness, a stable coating can be achieved in particular when using polytetrafluoroethylene (PTFE) as the coating material. Particular preference is given to using a condensate-resistant polytetrafluoroethylene and a resistant to high temperature differences on the tubular elements of the heat exchanger polytetrafluoroethylene.

The term _" substantially" means within the meaning of the invention

Deviations from the respective exact value by +/- 10%, preferably by +/- 5% and / or deviations in the form of changes insignificant for the function.

Further developments, advantages and applications of the invention will become apparent from the following description of the

Embodiment and from the figures. All described and / or illustrated features are alone or in any

Combination in principle subject of the invention, regardless of their summary in the claims or their dependency. Also, the content of the claims is made an integral part of the description

The invention will be explained in more detail using an exemplary embodiment in conjunction with the figures. FIG. 1 shows by way of example a device according to the invention for

hydrothermal carbonization of biomass with a single reactor in a schematic representation; 2 shows by way of example a device according to the invention for

hydrothermal carbonization of biomass with several cascaded reactors in a schematic representation. In the figures 1 and 2 by the reference numeral 1 plants for hydrothermal carbonation (HTC) are shown. The plant 1 is in this case designed to carry out an HTC process as a continuous process, ie, that the plant 1 a continuous or quasi-continuous operation when introducing the biomass into the reactor or when removing the coal from the reactor 5, 5 'allows without that the

Carbonation process in the reactor interior would be completely interrupted. The biomass processed in Appendix 1, which in particular can be dry biomass with a solids content of 2s 30%, is added to a

Biomass task 2 introduced into the Appendix 1 and by means of a

Controlled conveyor 3 or temporally intermittent the

Preheating 4 supplied. The conveyor 3 may in this case be a screw conveyor, a conveyor belt, a push floor conveyor or biomass with a high water content and a pump. In the preheater 4, which is preferably a pressure-resistant, apart from the supply and

Derived from closed containers, the biomass is heated, by directly introducing the dehydrated water into the biomass and by mixing the dehydrated water with the biomass, the dehydrated water is formed at least partially by dehydration in the reactor 5, 5 '. This water has a temperature in the range between 180 ° C and 240 ° C and can be used optimally for heat input into the previously to be heated biomass due to its high specific mass. When feeding the Dehydratwassers is preferably the

Preheater 4 pressure sealed. The maintenance of the

Preheating device 4 preferably has a non-stick coating of polytetrafluoroethylene (PTFE). For removal of the dehydrated water from the reactor 5, 5 'is preferably in between the upper and the lower reactor section 5a, 5a', 5c, 5c ' lying average reactor section 5b, 5b ', a removal device 5.1, 5.1' is provided, via which the Dehvdratwasser preferably can be withdrawn controlled via at least one valve and can be supplied via an immediate fluidic connection of the preheater 4.

After the at least partial preheating of the biomass is

Preferably, the pressure within the preheater 4, which has already risen by the supply of dehydrated water, increased to a pressure at least equal to the pressure inside the reactor 5, with pressures of 10 bar to 33 bar are preferred. The pressure increase takes place by means of a pressure generator 9 or a pressure accumulator coupled to the pressure generator 9. After increasing the pressure in the

Preheating 4, the preheated biomass or the mixture of biomass with the Dehvdratwasser via the inlet 5.2 to the reactor 5 is supplied to the case that prevails in the preheater 4, the same pressure as in the reactor 5, the biomass due to gravity introduced into the reactor 5 , Preference is given to an increase in the pressure in the preheating device 4 over the pressure in the reactor 5, so that clogging of the outlet of the preheating device 4 or of the inlet 5.2 of the reactor 5 is effectively avoided.

After introduction of the biomass into the reactor 5, this biomass is subjected to the hydrothermal carbonization, wherein water molecules are split off from the biomass in the dehydration process and thereby carbon particles are formed, which deposit in the lower reactor section 5a. To prevent deposits on the wall of the reactor 5, 5 ', this has at least partially on the inside a coating of polytetrafluoroethylene (PTFE). To increase the throughput rate of the processable biomass, it is possible, the process stages that lead to the carbonization of biomass, in several, cascaded reactors 5, 5 'to complete (Fig. 2). In this case, the outlet 5.3 of the first reactor 5 is connected to the inlet 5.2 'of the at least one further reactor 5', so that a first

Arbonisierungsteilprozess in the first reactor 5 and another

Karbonisierungsteilprozess in which at least one other reactor 5 'is completed. With such a cascaded arrangement of the reactors 5, 5 ', the exclusive removal of the coal sludge takes place at the outlet 5.3' of the further reactor 5 '. Furthermore, at the at least one further reactor 5 'is also a

Removal device 5.1 'provided for dehydrated water, which is also supplied to the preheater 4 for heat input into the biomass.

Preferably, the biomass introduced into the reactor are likewise added to catalysts which bring about acidification or alkalization of the biomass, the degree of addition of such

Catalysts, the structure of the resulting coal particles is determined. Furthermore, by suitable addition of catalysts of

Carbonation process can be accelerated. From the outlet 5.3 of the reactor 5, or the outlet 5.3 'of the further reactor 5' in cascaded reactors 5, 5 ', an aqueous coal sludge is removed, which is passed through a heat exchanger 10 for residual heat utilization. Through the heat exchanger 10, the coal sludge is at least partially deprived of the heat energy contained therein. This heat energy is supplied to a heat storage 1 1, so that acts as an intermediate buffer for the extracted heat energy.

Oer coal sludge is also passed through a filter device 8, which is preferably provided downstream of the heat exchanger 10, so that the already at least largely cooled coal sludge the

Filter device 8 flows through and thereby containing the coal sludge Foreign substances are deposited. Such foreign substances may be contained in the biomass plastics, metals, etc. Preferably, a further foreign substance sorting is provided in the area of the biomass feed 2 or the conveying device 3, by means of which coarse foreign substances are sorted out of the biomass to be processed. The filtered through the filter device 8 coal sludge is a drying and

Dewatering device 12 is supplied, in which the coal slurry is converted into dust-like carbon particles or coal dust. This coal dust can either be blown directly into a storage facility or fed to a pelletizer, in which the coal particles through

Addition of starch, in particular corn and or potato starch cross-linked and pressed into pellets.

Depending on the biomass used, the liquid produced during the dewatering process can either be used directly as a fertilizer or precipitated and used when using phosphate-containing or heavy metal-containing biomass, so that these phosphates and heavy metals are at least largely removed from the liquid. Part of the liquid withdrawn from the coal sludge by means of the drying and dewatering device 12 may be in-process

can be used and supplied to the pressure generator 9, so that the fluid can be used to increase the pressure in the preheater 4. Preferably, the plant 1 is connected to a heating device 13, which may be, for example, a biomass furnace, a combined heat and power plant or a fossil fuel using heater. The from the

Heating device 13 resulting gases, in particular flue gases are the reactor 5 and the reactors 5, 5 'fed via flue gas ducts 13.1 inside the reactors 5, 5' is in each case at least one

Heat exchanger 6 is provided, which is in particular a tube heat exchanger and a plurality of preferably vertically arranged pipe elements 6.1, which are connected to the flue gas ducts 13.1 and are flowed through by the flue gas. After passing through the heat exchanger 6, the flue gases from the reactors 5, 5 'out and preferably a heat exchanger 7, by means of which the flue gas residual heat energy is withdrawn and the heat storage 11 is supplied , To remove deposits of biomass or

To prevent process intermediates on the heat exchanger, this also has a non-stick coating, which also made

Polytetrafluoroethylene (PTFE) may be formed.

Preferably, a mixing device is provided in the flue gas lines 13.1 between the heater 13 and the reactors 5, 5 ', which allows a mixing of the flue gas with a controlled amount of cold air or fresh air. As a result, the flue gas temperature or the heat input into the reactors 5, 5 'is controlled via the heat exchanger 6. The required heat input into the reactors 5, 5 'depends largely on the biomass used or the dry fraction of this biomass, wherein biomass with a higher dry content has a lower

Heat input required as biomass with an increased dry content. Due to the controlled supply of flue gas the respective required heat demand can be taken into account depending on the processed biomass.

The invention has been described above by means of an embodiment. It is understood that numerous modifications and

Changes are possible without thereby departing from the inventive concept.

Claims

Device for the hydrothermal carbonization of biomass, with a reactor wall having a reactor (5, 5, in which the biomass is dehydrated and carbonated, wherein the reactor on the inside of the reactor wall at least partially has a coating that prevents adhesion of the biomass, characterized in that the reactor contains a heat exchanger (6) designed for the passage of flue gases or steam, this heat exchanger (6) having a coating which prevents adhesion of the biomass and that the coating of the reactor wall and the heat exchanger (6) has a coating Device according to claim 1, characterized in that the entire reactor wall is coated on the inside. Device according to one of the preceding claims, characterized in that all elements contained in the reactor have the coating nem of the preceding claims, characterized in that having a wall

Preheating is provided for heating the biomass supplied to the reactor and that this wall of the

Preheating at least partially has a coating that prevents adhesion of the biomass to the wall Device according to one of the preceding claims, characterized in that the coating has a layer thickness of 15- 20μm.