DE102011056720A1 - Hydrothermal carbonation of organic material, comprises converting organic material in presence of water by adding water and/or catalyst in the absence of air when compared with standard conditions of elevated pressure and temperature - Google Patents

Abstract

The method comprises converting an organic material as feedstock in presence of water by adding water and/or a catalyst in the absence of air when compared with standard conditions of elevated pressure and temperature by a hydrothermal conversion reaction in a coal and an aqueous liquid. The feedstock: is formed from different aqueous organic component and a dry component; and consists of cellulose and sawdust. The aqueous organic component includes aqueous biomass from organic wastes such as vegetable and/or animal constituents, seaweed and/or small- or micro-organisms, and/or bacteria. The method comprises converting an organic material as feedstock in presence of water by adding water and/or a catalyst in the absence of air when compared with standard conditions of elevated pressure and temperature by a hydrothermal conversion reaction in a coal and an aqueous liquid. The feedstock: is formed from different aqueous organic component and a dry component; and consists of cellulose and sawdust. The aqueous organic component includes aqueous biomass from organic wastes such as vegetable and/or animal constituents, seaweed and/or small- or micro-organisms and/or bacteria, and sludge. A ratio of the mass, molecular weight and/or volume fractions of the two components is predetermined, where the ratio of the components to one another is 80-20. One of the components such as sewage sludge is pretreated and/or treated prior to addition to the feedstock by mechanical, chemical and/or biological pathways such as fermenting, digesting, filtrating, mixing, drying, humidifying, crushing and/or homogenizing and by a purification plant process. The feedstock is pretreated before and/or during the hydrothermal carbonation by mechanical, chemical and/or biological pathways and by the purification plant process. The feedstock and/or the component has a maximum water content of 60% prior to the hydrothermal carbonization. An independent claim is included for a device for the hydrothermal carbonation of organic material such as biomass.

Description

The invention relates to a method for hydrothermal carbonization of organic material according to the preamble of claim 1. Furthermore, the invention relates to a device only hydrothermal carbonization of organic material according to the preamble of claim 10.

Hydrothermal carbonation is a well-known process for charring organic matter, dating back to Nobel Laureate Friedrich Bergius. Essentially, the goal is to produce carbon or coal from organic material or biomass under exclusion of air at elevated pressure and temperature. The process usually takes place in a pressure vessel into which the organic material to be converted and a sufficient amount of water are introduced. Optionally, a catalyst can be added.

Unlike fossil carbonization in the ground, typically only about 10 bar to 40 bar and between 190 ° C and 300 ° C are necessary here. The introduced organic material as a feedstock is then almost completely converted to coal and an aqueous liquid.

The organic materials originally used for the hydrothermal carbonization are in particular wood and other, preferably vegetable biomasses. With such a comparatively reliable high-quality coal can be produced, which has at least the calorific value of lignite. Typical calorific values are approximately between 25 MJ / kg and 30 MJ / kg.

Due to the widespread trend towards renewable energies, the suitability of various other organic materials for hydrothermal carbonization has been investigated in recent years in particular. However, it has generally been found that, in particular, animal waste is only of limited use. Instead of producing a high-quality, almost pure coal, such biomass, which usually also contains large amounts of bacteria, usually produces an oily mixture of a large number of difficult-to-separate liquid and solid substances, which are only a small part of coal is.

The object of the present invention is to provide a method for the hydrothermal carbonization of organic material, which is particularly suitable for the production of high-quality coal with sufficient calorific value from animal biomass as organic material as a feedstock.

The problem underlying the invention is achieved by a method with the measures of claim 1. Accordingly, the feedstock from several, ie in particular at least two, preferably organic components formed. Accordingly, the feedstock preferably contains at least two, in particular, different components from which the feedstock is co-formed. With components or organic components preferably substances or mixtures are referred to, which are found in this form used, for example in nature and / or produced in this form and / or for example as waste from other processes are available. Through a mixture of at least two components, the properties of the composition can be adjusted in such a way that, as a result, a high-quality product, at least similar to coal, is produced. If necessary, the parameters of the hydrothermal carbonization can be adapted accordingly.

In particular, the feedstock is at least substantially formed from two or more components, in particular organic components. In this case, the components are preferably different, ie in particular have different chemical constituents and / or a different structure and / or composition and / or consistency, etc. By only two components as main components, the properties of the composition of the feed can be particularly well reproducible influence. However, more than two, in particular three, four, five, six or more components can be combined. All that needs to be ensured is that the properties with regard to the implementation of the hydrothermal carbonization can be defined and preferably set reproducibly.

Preferably, the feedstock is formed from at least one of a wet or aqueous, preferably organic, component and at least one dry, preferably organic, component. More preferably, at least substantially each exactly one aqueous component and a dry component are combined. As an aqueous component or wet (aqueous) biomass, water-containing organic materials or substances are referred to. The water content is generally at least 15 percent, but may also be lower. The water may be present in attached or bound form in the feedstock. As so-called dry components or dry biomass is called organic materials with a low water content of in particular at most 15 percent, such as preferably wood, dead or dry plant parts, etc. It can Preferably both solid (eg wood, organic waste, plant constituents) and liquid (eg oils, such as rapeseed oil etc.) are used as aqueous or dry components individually or in combination with each other.

As one of the components, a dry component is preferably used. In particular, a feedstock consisting of cellulose is used. These are preferably at least partially wood, in particular comminuted wood, for example in the form of sawdust. Wood has a high cellulose content or consists almost completely of cellulose. These carbon compounds or polymeric carbohydrates can be reacted well and in particular almost completely in hydrothermal carbonation. By comminution, for example, as sawdust or the like, is preferably provided for a fine dispersibility. In addition, the chemically active surface of the feedstock is increased. Preferably, a mixing of the components takes place before the start of the hydrothermal carbonization.

A wet or aqueous material, in particular biomass, is preferably used as one of the components. These are, for example, organic, in particular vegetable and animal residues or waste. In addition, preferably food residues come into consideration, such as in particular organic waste, so the content of the so-called biotones or biowaste bins. Preferably, however, sewage sludge is used. The constituents of the aqueous biomass include, in particular, microorganisms, bacteria, algae, etc. The aqueous biomass preferably contains a dry mass of not more than 85 percent, that is, conversely, a water content of at least 15 percent. Preferably, at most 50 percent, more preferably at most 10 percent dry matter are included.

The two components are preferably combined in a predetermined ratio to each other to the feedstock. However, it is also possible to add additional more or less smaller amounts of a further, in particular organic component. The ratio of the proportions of the components to one another is usually determined by the ratio of the mass, molar mass and / or volume fractions. Preferably, the ratio of the organic components to one another is determined to be between 1: 99 and 99: 1. This means that between 1 and 99 percent of one component and accordingly between 99 and 1 percent of the other component are merged. In particular, the ratio may also be between 5 to 95 and 50 to 50. More preferably, the ratio is between 10 to 90 and 30 to 70. More preferably, the ratio is about 20 to 80. Preferably, the aqueous component is used for the major portion, while only the minor portion is typically about 1 to 30 percent the dry component is added. This makes it possible to vary the properties of the feedstock or organic material resulting from the combination of the components. In addition, only a relatively small proportion of the high-quality dry biomass is needed. Preferably, this proportion is not more than about 30 percent of the total mass of the feedstock. Optionally, however, the components may also be added outside the specified limits in any desired mixing ratio, provided that corresponding advantages result.

In a preferred embodiment of the invention, at least one of the components is treated or pretreated. This is preferably done before adding to the feed. The treatment or pretreatment is carried out in particular by a digestion process, mixing, drying, watering, comminution and / or homogenization. In principle, all conceivable chemical and / or biological and / or mechanical treatments can be used alone or in combination. If the component is sewage sludge, a pretreatment in a sewage treatment plant can preferably be carried out by the processes customary there. Thus, at least one clarification process is performed. This means that at least one of the usual conversion processes of a sewage treatment plant, ie in particular fermentations, filtrations, biological conversions by means of bacteria, Drying, etc. are also performed here. In particular, sewage sludge is taken as a component of a sewage treatment plant.

Preferably, the feedstock is treated prior to and / or during the hydrothermal carbonation process. This is preferably done before adding to the feed. The treatment or pretreatment is carried out in particular by a digestion process, mixing, drying, watering, comminution and / or homogenization. In principle, all conceivable chemical and / or biological and / or mechanical treatments can be used alone or in combination. If the feedstock is at least partly sewage sludge, a pretreatment in a sewage treatment plant can preferably be carried out by the usual methods there. Thus, in particular, at least one clarification process or sewage treatment process is carried out. This means that at least one of the usual conversion processes of a sewage treatment plant, ie in particular fermentations, filtrations, biological conversions by means of bacteria, drying, etc., are also conducted here. In particular, sewage sludge is taken as a component of the feedstock of a sewage treatment plant.

In particular, the water content of the feedstock and / or the at least one component is changed before carrying out the hydrothermal carbonization or before mixing with further preferably organic components. Preferably, a maximum water content of 95 percent is set. This corresponds to a dry matter of at least 5 percent. Preferably, the water content is at most 80 percent, more preferably at most 70 percent. In order to change or adjust the water content, water must be added or removed in particular accordingly. For this purpose, on the one hand, an addition of water and, on the other hand, processes such as drying, filtration, evaporation and / or the like can be used. In particular, the water content is adjusted so that a water addition for carrying out the hydrothermal carbonization is not required. Preferably, the water content of the feedstock is just the required, ideal water content for starting the reaction of the feedstock into coal and the liquid phase.

The underlying object of the invention is also achieved by a device for carrying out the method described above. The device has for this purpose a container for receiving the feedstock for carrying out the hydrothermal carbonization in the interior of the container. Accordingly, the container is in particular a pressure vessel.

Preferably, the hydrothermal carbonization is carried out under a pressure of at least 10 bar. However, the pressure is preferably between 12 bar and 70 bar, more preferably between 15 bar and 40 bar, particularly preferably about 32 bar. The reaction is preferably carried out at a temperature of at least 180 ° C, preferably between 200 ° C and 300 ° C, more preferably between 220 ° C and 280 ° C, most preferably at about 240 ° C.

In the following, a preferred embodiment of the invention is described: The method according to the invention serves for the hydrothermal carbonization of organic material or biomass. The organic material as a feed is reacted in the presence of water under elevated pressure and temperature in carbon and an aqueous liquid as reaction products. The complex carbon compounds of the feedstock are broken up and converted into more or less other complex carbon compounds. These carbon compounds are usually two or more bonded carbon atoms, often in a chain, but possibly also reticulated. At these other chemical constituents, but usually as individual radicals, such as oxygen atoms, hydrogen atoms, nitrogen atoms and the like, be bound.

At least one organic material or feedstock and water are required as reaction educts. The water may also already be contained in the feedstock, for example in stored or partially bound form. This is the case, for example, in wet or aqueous biomass, such as organic waste, animal and / or vegetable residues, algae, or sewage sludge. Finally, a relatively small amount of chemical catalyst (maximum of a few percent of the total mass), which is usually an acid such as citric acid, can be added as a support. Depending on the composition of the feedstock, however, catalytic compounds are often already present in sufficient quantities, in particular in the form of carbonic acid.

In the present case, the feedstock or organic material consists of at least two components or organic components. This is in particular an aqueous component as material, as is the case with sewage sludge or algae. In general, animal and vegetable waste or residues can be added mixed. In order to achieve satisfactory results even with these aqueous components, the so-called wet or aqueous biomasses, according to the invention, at least one second dry (organic) component is additionally added. This is, for example, a cellulosic material. Wood in the form of sawdust is particularly well suited for this purpose because of its good distribution and, at the same time, its ideal suitability for hydrothermal carbonation. The aqueous component or aqueous biomass brings at a dry matter of at most about 20 percent to 30 percent, often only at most 10 percent, usually sufficient water to the added dry component or dry biomass also with sufficient water for hydrothermal carbonation supply. Thus, the addition of additional water can be dispensed with.

The proportion of the dry component in the entire feedstock relative to the aqueous component is usually in the range of about 10 to 90 to 30 to 70. This means in particular that 10 to 30 parts of the dry component to each about 90 to 70 parts of the aqueous or dry component come. The appropriate mixing ratio is used to set the respectively desired or required condition.

In order to carry out the reaction of the hydrothermal carbonization optimally, a treatment or pretreatment of the feedstock or of the at least one component thereof takes place. In particular, the aqueous components or the sewage sludge are usually pretreated by mechanical, biological and / or chemical means. The mechanical treatment is, in particular, filtrations, mixtures, comminutions, but also the addition and / or removal of water. As a chemical treatment, the addition of different chemicals as well as the partial implementation in chemical processes into consideration. In the context of biological processes, for example, transformations or metabolism can be carried out by microorganisms, bacteria, algae, etc., ie fermentations. Both the microorganisms and their degradation products are then fed to the feed as an aqueous component.

The dry feedstock or the dry component, for example the wood, is in particular comminuted, preferably chopped and / or added in the form of sawdust. Likewise, for example, a pretreatment of the feedstock or a component by addition of chemicals or the like can take place.

The multi-component feedstock may also be pre-treated or post-treated according to mechanical and / or chemical and / or biological means. In order to allow as complete a reaction as possible, at least a mixing of the components must be carried out together. This ensures that the reaction conditions are at least substantially the same in at least almost the entire reactor volume with respect to the mixture of Reaktionsedukte at least. This may possibly eliminate a change in the local process parameters and / or a time-dependent change in the course of the reaction, in particular temperature and pressure, at least due to a nonuniform material composition.

The conditions of increased pressure and elevated temperature for carrying out the hydrothermal carbonization are finally produced in a gas and pressure-tight sealable pressure vessel. During the reaction, a pressure prevails in the container of usually about 25 bar to 35 bar and a temperature of about 230 ° C to 250 ° C. Since the reaction is exothermic, that is, gives off heat to the environment, the reaction after initial initiation by heating the container will usually be self-contained, as more than sufficient heat energy from the process will be replenished. In general, even cooling, such as through a cooling circuit, will have to be additionally provided to dissipate the excess heat. After about 2 to 8 hours, typically more than 90 percent of the carbon of the feed is in the coal so that the reaction products can be withdrawn. The resulting coal is for this purpose removed from the aqueous liquid, for example by filtration, centrifuging, pressing, drying and / or the like.

Claims (10)

A process for the hydrothermal carbonization of organic material, in particular of biomass, wherein the organic material as feed in the presence of water, preferably with the addition of water and / or a catalyst, with exclusion of air under normal pressure conditions elevated pressure and elevated temperature by a hydrothermal conversion reaction at least Substantially in coal and an aqueous liquid is reacted, characterized in that the feedstock of several different components is formed. A method according to claim 1, characterized in that the feedstock is at least substantially formed of two or more preferably different, in particular organic components. A method according to claim 1 or 2, characterized in that the feedstock is formed at least from at least one aqueous component and at least one dry component, preferably at least substantially each of an aqueous and a dry component. Method according to one of the preceding claims, characterized in that is used as one of the components, preferably as the dry component, an at least substantially consisting of cellulose feedstock, preferably at least partially wood, especially sawdust. Method according to one of the preceding claims, characterized in that one of the components, preferably as the aqueous component, an aqueous biomass is used, preferably at least partially from organic waste, in particular plant and / or animal components, preferably at least partially from algae and / or small or microorganisms and / or bacteria, etc., more preferably sewage sludge. Method according to one of the preceding claims, characterized in that the ratio of the mass, molecular weight and / or volume fractions of the two components to each other at least substantially predetermined, the ratio of the components to each other preferably determined to be between 1 to 99 to 99 to 1 is, preferably to between 5 to 95 to 50 to 50, more preferably between 10 to 90 and 30 to 70, in particular about 80 to 20. Method according to one of the preceding claims, characterized in that at least one of the components, in particular the sewage sludge, preferably before addition to the feedstock, is treated or pretreated, in particular by mechanical and / or chemical and / or biological means, preferably a fermentation and / or or digestion and / or filtered and / or mixed and / or dried and / or moistened and / or comminuted and / or homogenized, more preferably by means of at least one treatment plant process. Method according to one of the preceding claims, characterized in that the feedstock before and / or during the hydrothermal carbonization is treated or pretreated, in particular by mechanical and / or chemical and / or biological means, preferably subjected to fermentation and / or digestion and / / or filtered and / or mixed and / or dried and / or moistened and / or comminuted and / or homogenized, particularly preferably by means of at least one sewage treatment plant process. Method according to one of the preceding claims, characterized in that the feedstock and / or the at least one component is brought to a maximum water content of 95 percent before carrying out the hydrothermal carbonization, preferably at most 80 percent, more preferably at most 70 percent, most preferably maximum 60 percent. Apparatus for carrying out the method according to one of the preceding claims with a container, in particular pressure vessel, for receiving the feedstock for hydrothermal carbonization.