DE102012024463B4 - Method and device for process water treatment from hydrothermal carbonization - Google Patents

Abstract

Process for the treatment of process water from the hydrothermal carbonization (HTK), wherein the effluent water of the HTK process is supplied to at least one aquatic plant culture facility in which the aquatic plant cultures are cultivated in culture basins stacked with interstices and arranged in a closed photobioreactor, and the cultural facility in the upper floors is populated with Myriophyllum and in the lower floors with duckweed, such that in or on the bottom of the aquatic cultural institution a surface created Vorlaufbeckenvolumen is fed as buffer volume with HTK process water and diluted with mixed water, and that afterwards the process water Mixed water mixture is fed as culture water to the stacked aquatic plant cultures for evaporation, wherein the existing from Myriophyllum (millet leaf) aquatic plant cultures in the upper floors of the aquatic plant culture institution Overhanging be cultivated, and wherein at least the first crop after commissioning of the crop is harvested so that it falls down into the upwardly open feed tank and the plant sections populate the supply pool with a floating closed plant cover for odor damping.

Description

The invention relates to a process and a device for process water treatment from the hydrothermal carbonization according to the preamble of claims 1 and 8. The prior art discloses the hydrothermal process for the treatment of biomass in various process embodiments. Ultimately, this is one of the few ways in which actual final CO2-effective binding occurs in solid carbon. Thus, this form of waste disposal represents a sustainable CO2-binding climate measure. The pure carbon obtained here can be stored, or used as a filter coal, or even as an energy source. From the DE 10 2011 115 869 A1 , as well as the DE 10 2010 019 352 A1 , as well as the DE2503758A1 , as well as the WO2010 / 043323A2 , as well as the DE 10 2010 052 403 A1 are known aquatic cultural facilities in which the aquatic plants are cultivated in a stacked tub system. The tubs are rinsed with culture water whose ingredients are absorbed by the plants. Thus, it is essential that the culture water contains ingredients at all. Thus, for example, biomass problem wastes, such as fermentation residues from biogas plants, in carbon substrates, biochar can be transferred. A waste disposal problem which often arises, among other things, is phenolic-rich effluent water of so-called HTK processes. Because of the substantial material reduction of the introduced biomass or waste, such effluent water must not be introduced into the wastewater network without preliminary purification.

Thus, either the disposal or the treatment of such effluents always very fundamentally question the economics of such HTK processes.

In addition, the disposal of landfill wastewater is also a major problem.

Process wastewaters from food production as well as municipal wastewaters with pharmaceutical load pose the conventional wastewater treatment plants with extreme, sometimes not solvable requirements.

The invention is therefore an object of the invention to further develop a method and a device of the generic type that the effluents can be treated so effectively that the cost of the respective processes from which the wastewater, significantly increased or less by the cleaning is charged.

The stated object is achieved according to the invention in a method of the generic type by the characterizing features of claim 1.

Further advantageous embodiments of the method are given in the dependent method claims 2 to 7.

With regard to a device of the generic type, the object is achieved by the characterizing features of claim 8.

Further advantageous embodiments are specified in the remaining dependent claims.

The core of the process according to the invention is that the effluent water of the HTC process is supplied to at least one aquatic plant culture facility in which the aquatic plant cultures are cultivated in culture basins stacked one above the other with interstices and arranged in a closed photobioreactor, such that the aquatic plant is in or on the ground Culture equipment a flat-laid Vorlaufbeckenvolumen is fed as buffer volume with HTK process water and diluted with mixed water, and that thereafter the process water / mixed water mixture is fed as culture water the stacked aquatic crops to evaporation.

In a further advantageous embodiment, it is stated that the amount of water evaporated by transpiration and / or transferred by Gutation through the plant body by condensation and / or dripping water return back to the flow tank volume is returned by Rücktropfung, and so at least represents a part of the mixed water, with the Process water is mixed at feed.

Furthermore, it is designed so that the volume of water in the supply basin is dimensioned such that it is a multiple of the sum of daily supplied HTK process water volume plus mixed water / condensate / Rücktrropfwasservolumen. The aquatic plant cultures consist partly of Myriophyllum, which are cultivated on the upper floors of the aquatic plant culture facility overhanging. So they can be easily harvested by cutting using a stacker crane, which is movable between the shelves.

It is also envisaged that at least the first crop after commissioning of the crop will be harvested so that it falls down into the upflow pool open to the top and the plant sections to the supply pool with a floating closed plant cover for Settle odor damping. This is important so that the bioreactor can also be walked on by staff.

Furthermore, it is advantageous that the temperature and / or the pH and / or the conductivity and / or the water level is measured in the flow tank, and that these values according to the mixing ratio of HTK process water fed and mixed water is kept as constant as possible by regulated Supply of process water / wastewater and / or well water, and / or service water and / or municipal wastewater. These parameters can be used to control the reactor very easily and effectively. In this case, the maximum values or acceptance values previously specified for the crops used are taken into account in the limit values to be taken into account in the pH value, conductivity value and temperature, and depending on this, the mixing ratios between supplied process water and the mixed water are currently controlled. In a further advantageous embodiment, it is stated that in order to create a conclusive heat concept and an optimized biomass growth of the plant culture facility or the feed basin both the hot process water from the HTK or industrial process, as well as waste heat from the HTK or industrial process and / or residual heat of a power generation or to another production process.

Furthermore, it is configured that the aquatic plant culture facility is harvested daily with a Teilbesterntung the cultures, and so the biomass growth and the process water treatment is stimulated.

Likewise, the relative humidity and / or the absolute humidity in the culture device is measured, and the otherwise closed culture device is made to be ventilated to the outside as needed.

With respect to a device of the generic type, the essence of the invention consists in that the waste water or the effluent water of the HTK process can be fed to at least one aquatic plant culture facility in which the aquatic plant cultures are cultivated in culture basins stacked one above the other with interstices and arranged in a closed photobioreactor are, which is provided in or on the bottom of the aquatic cultural institution with a flat-shaped flow cell volume as a buffer volume, which can be fed with HTK process water and dilutable with mixed water, after which the process water mixed water mixture is fed as culture water the stacked aquatic crops to evaporation.

Thus, there is also further configured that the plant culture device is a multi-level plant culture facility, such that the process wastewater is fed in pure or mixed with dilution water form as culture water first a first crop to the first treatment step, and then at least one other crop for at least a further treatment step is supplied.

In addition, it is provided that the storage system in which the culture tubs are stacked, consists of a frame shelf system in which the culture tubs are arranged alternately from bottom to top alternately to the opposite outer sides.

Furthermore, the cultural institution in the upper floors with Myriophyllum and settled in the lower floors with duckweed.

A further embodiment provides that the outer skin of the closed or partially closed aquatic plant culture facility is provided with a Gothic or polygonal roof line, which is at least 1/3 of the total height of the cultural institution or the transparent outer skin of the cultural institution, and to optimize the incidence of light on the aquatic plant cultures serves.

In addition, the largely parallel shelves of the aquatic cultural facility are aligned lengthwise in a north / south direction of the compass. As a result, the OST-West sun gear is completely covered by all shelves. This brings optimal light times in the cultural institution.

HTK processes run in such a way that biomass is fed to a closed pressure-resistant reactor space, and this reactor space is heated to temperatures of, for. B. at 250 ° C or more, and the reactor space at the same time as in an autoclave is pressurized. After the supply of a start-up thermal energy, the further carbonization process is exothermic. In the end, a critical drainage and a precipitated biochar remains. The said effluent water is in many cases, for example, highly phenolic and therefore may not be discharged directly into the sewage network. The metabolism and thus the disposal of wastewater-hazardous ingredients is carried out without primary energy supply, as only waste heat, if it is even needed. HTK effluents mostly contain phenolic compounds. These are especially but not exclusively absorbed and metabolized by floating aquaculture plants, such as squirrel and / or juncus. An accumulation of ingredients that are not metabolized takes place only with heavy metals. It is important, however, that the heavy metal binding takes place to a striking extent by the Eichhornia.

At a minimum, it removes the heavy metals almost completely from the culture water so that it is secreted and collected in the plant mass. It has been shown that especially but not exclusively the critical element lead from the culture water to which the HTK wastewater is mixed is collected in the Eichhornia. It has been shown that, for example, the element lead deposits exclusively in the root beards of the squirrel, while at the same time remains in the remaining parts of the plant lead below the detection limit. This very special property leads to the fact that the remaining plant is still suitable for biomass utilization, for example recycling as a biomass sub-stream into the HTK process, without there being an accumulation of lead, if the HTK process and the biomass-producing Wastewater purification process would be coupled. Only the roots of the Eichhornia cultures have to be decoupled from the process and must not be driven in a circle.

At the same time, the combined operation of a HTK plant with such an aquatic plant culture facility results in the biomass obtained as a biogenic filter substrate being at least partially supplied to the system and the valuable biochar can be obtained therefrom. Thus, this form of wastewater treatment is at the same time an increase in the total energy obtained, instead of being energy-consuming. The reason lies in the fact that such a wastewater treatment plant feeds on the photosynthesis of solar energy.

Regardless of such a biogenic wastewater treatment is also applicable to landfill wastewater or leachate, but also for pharmaceutical wastewater. Thus, even by the proximity of the arrangement of such an aquatic culture plant to a HTK plant or other processes in which waste heat is obtained, a high waste heat utilization efficiency can be achieved with the aquatic plant culture facility for wastewater treatment.

The reason for the resulting synergy of this waste heat utilization by the aquatic plant culture facility is that, in particular when populated with Myriophyllum, Eichhornia, Juncus, and possibly even Lemnacea or Spirodela, they maximize biomass propagation at a temperature of around 30 ° C + / - reach 5 °. The biomass propagation goes parallel to the wastewater purification performance. Ie. Maximizing the biomass propagation means, to a first approximation, maximizing the water purification performance.

First approximation here means only that the effect is to be considered that the solubility of CO2 in the culture water decreases with increasing temperature. Since these aquatic plants are primarily so-called floating aquaculture plants, they absorb enough high amounts of CO2 from the gas phase.

An embodiment of the invention is illustrated in the drawing and described in more detail below.

The drawing shows an aquatic cultural institution in a side view. In this case, the outer shell consists of a so-called double-walled film block (greenhouse), which contains integrated on the floor or in the ground as large as possible the so-called supply pool. On or in the corresponding shelves are installed, which are arranged in rows in which not least by the gable form resulting individual ships of the greenhouse or bioreactor fill this in the Gothic form shown by different heights of the shelves. The fact that the roof is divided into spreading gables, which can make up about one third of the total height in height, is introduced together with the described arrangement of different heights shelves, an optimum of light in the bioreactor. In addition, many aquatic plants are low light plants, or at least tend to be low light plants. Therefore, the available and yet optimally distributed light is sufficient. Another optimization is the staggered arrangement of the culture water pans on opposite sides of the rack.

When starting such a water treatment reactor, the tanks are first filled with culture water and made a start colonization. This can then be populated without harvesting first to a natural or breeders achieved border coverage. Then the water is first directed into the supply basin. There it is first mixed in the desired mixing ratio, for example 1 to 5 or 1 to 10 with well water. That For example, one part of wastewater to 5 parts of well water.

Then, the wastewater / water mixture is then pumped in tiers in the culture tubs, or pumped all the way to the top and then overflow and the lower tubs gradually filled. The first harvest of the Myriophyllum, for example, hanging over the edge far to the front, is not taken from it, but only dropped down into the supply basin so that it also colonizes, in such a way that a kind of scent is created on it.

Then a part of it is regularly harvested and that is exactly as much as grows again until the next harvest, for example every day, or every 2 to 10 days. Since aquatic plants are extremely fast-growing, it is quite possible to harvest 7 to 25% of the boundary or plant cover because this amount actually grows in the given cycle times.

The exploited mechanism is now the following. The aquatic plants have an extremely high evaporation rate, several liters per day and square meters of aquaculture. By driving in the day and night cycle is a condensation of the evaporated amount of water regularly, so that it drips down automatically into the original tank. The Myriophyllum used not only perform transpiration, but also the so-called gutation. This is the direct passage of culture water through the plant body without evaporation. This proportion drips back into the original basin.

All water that has passed through the plant body through transpiration and gutation is thus purified. It is important to realize that this water is a multiple of the water bound in the plant. Ie. the cleaning capacity is not the wet mass removed by the harvest minus dry masses, but a multiple thereof, much more than tenfold.

Due to the regular harvesting, there is also no saturation of the absorption of ingredients from the culture water. Thus, the harvest of the biogenic filter body is renewed daily.

The dripping water is almost distilled water and thus produces a closed water cycle during further operation, so that no well water is needed for mixing after the start. Only minor drag losses due to airing must be refilled.

Thus, the dripping permanently dilutes the waste water concentration in the feed tank, so that wastewater can be topped up to the original tank precisely within the scope of this reduction until it again corresponds to the desired acceptance values with regard to pH value, conductivity, etc.

The figure shows the device or culture device according to the invention for the aquatic plants.

The flat Kulutrwannen 3 are in floors on shelves 3 arranged one above the other. The height shown corresponds to about 3.5 to 4.5 meters, so that there is a distance in height between the tubs of about 30 centimeters. The cultural institution is divided into three ships, but they are open to each other or can be. The picture also shows the respective displacement of the tubs to each other in each shelf, so as to have optimal light incidence. The floor is as a foundation 4 designed, and on the foundation 4 or integrated in the foundation is the feed basin 5 arranged, which is operated in the manner described above. The shelves 2 are corrosion resistant. The incoming wastewater is mixed down in the feed tank with the Rücktropfwasser of condensation and / or Gutation and / or well water, or it is so much wastewater each tracked or virtually continuously updated until the defined mixing ratio is restored.

The shelves are in their longitudinal extension, d. H. aligned in the plane of representation in north-south direction, so that the sun gear from east to west all day from each shelf is detected approximately equally. This ensures the optimal luminous sum distribution in the cultural facility.

LIST OF REFERENCE NUMBERS

1

Cultural institution with foil or glass enclosure

2

Shelves or rows of shelves

3

Tubs or culture tubs

4

foundation

5

Floor trough, supply trough

Claims (10)

Process for the treatment of process water from the hydrothermal carbonization (HTK), wherein the effluent water of the HTK process is supplied to at least one aquatic plant culture facility in which the aquatic plant cultures are cultivated in culture basins stacked with interstices and arranged in a closed photobioreactor, and the cultural facility in the upper floors is populated with Myriophyllum and in the lower floors with duckweed, such that in or on the bottom of the aquatic cultural institution a surface created Vorlaufbeckenvolumen is fed as buffer volume with HTK process water and diluted with mixed water, and that afterwards the process water Mixed water mixture is fed as culture water to the stacked aquatic plant cultures for evaporation, wherein the existing from Myriophyllum (millet leaf) aquatic plant cultures in the upper floors of the aquatic plant culture institution Overhanging be cultivated, and wherein at least the first harvest after commissioning of the plant culture is harvested so that this down into the upwardly open feed tank falls and the plant sections settle the fore tank with a floating closed plant cover for odor damping. A method according to claim 1, characterized in that the evaporated by transpiration and / or by Gutation through the plant body through transferred amount of water is returned by condensation and / or drip water return back to the flow tank volume, and thus represents at least a portion of the mixed water, with the process water at Feed is mixed. A method according to claim 1, characterized in that the water volume in the flow basin is dimensioned such that it is a multiple of the sum of daily supplied HTK process water volume plus mixed water / condensation / Rücktrropfwasservolumen. Method according to one of the preceding claims, characterized in that the temperature and / or the pH value and / or the conductivity and / or the water level is measured in the flow basin, and that according to these values, the mixing ratio of HTK process water supplied and mixed water as possible is kept constant, by controlled supply of process water / wastewater and / or well water, and / or service water and / or municipal wastewater. Method according to one of the preceding claims. characterized in that to create a coherent thermal concept and an optimized biomass growth of the plant culture facility or the feed basin both the hot process water from the HTK or industrial process, as well as waste heat from the HTK or industrial process and / or the residual heat of a power generation or other production process is supplied. Method according to one of the preceding claims, characterized in that the aquatic plant culture facility harvested daily with a Teilbesterntung of the cultures, and so the biomass growth and the process water treatment is stimulated. Method according to one of the preceding claims, characterized in that the relative humidity and / or the absolute humidity in the culture device is measured, and demand-controlled the otherwise closed culture device is vented to the outside. Means for the treatment of process water from the hydrothermal carbonization, with at least one aquatic plant culture facility to which the effluent water of the HTK process is fed, in which the aquatic crops are cultivated in one above the other with interstices stacked and arranged in a closed photobioreactor culture pans, which in or on the soil of the aquatic cultural institution is provided with a two-dimensional flow cell volume as a buffer volume, which can be fed with HTK process water and dilutable with mixed water, after which the process water mixed water is fed as culture water stacked aquatic plant cultures for evaporation by the mixture to the very top is pumped and then overflow over the lower troughs gradually fills, the cultural institution is populated in the upper floors with Myriophyllum and in the lower floors with duckweed, the Stellage nsystem in which the culture tubs are stacked, consists of a frame shelf system in which the culture tubs are arranged alternately shifted from bottom to top, respectively, to the opposite outer sides, and these largely parallel shelves of aquatic cultural facility lengthwise in a north / Süd-Himmelsrichtungsverlauf are aligned, such that the sun-way East-West is completely covered by all shelves equally. Device according to claim 8, characterized in that the plant culture device is a multistage plant culture device, such that the process waste water is fed in pure or mixed with dilution water form as culture water first a first crop to the first treatment step, and then at least one other crop for at least one further treatment step is supplied. Device according to one of claims 8 to 9, characterized in that the outer skin of the closed or partially closed aquatic plant culture device is provided with a Gothic or polygonal roof line, which is at least 1/3 of the total height of the cultural institution or the transparent outer skin of the cultural facility, and for optimization light incidence on aquatic crops.

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