EP1748268A2 - Process for drying goods. - Google Patents

Abstract

In the drying of materials, e.g. wood (7), in a chamber (3) with tubing (12), connected with a heater (14) via a heat exchanger (13) and with a circulating device (11), forming a heating circuit for the chamber, the circulating gaseous drying medium (10) is not exchanged during the drying procedure and abstracts at most the amount of water vapor produced from the wood during drying. A method for drying materials, e.g. wood (7), is carried out in a plant (2) with a chamber (3) with closable feed opening(s) (4). Tubing (12) leads from openings in the chamber, and is connected with a heater (14) via a heat exchanger (13) and with a circulating device (11), forming a heating circuit for the chamber. The novel features are that: (1) the circulating gaseous drying medium (10) (specifically hot air) is not exchanged during the drying procedure and abstracts at most the amount of water vapor produced from the wood during drying; and/or (2) the heating medium in the heater (14) is a thermal oil containing or consisting of a glycol. An independent claim is included for corresponding drying apparatus, in which the tubing is connected with the chamber via a first connection (18) in the region below the material to be dried (specifically for supply of drying medium) and another connection (9) in the region above the material to be dried (specifically for abstraction of drying medium).

Description

The invention relates to a method for drying goods, in particular wood or wood products, in which the goods are dried in a plant having at least one chamber, which is provided with at least one, with a closure means closable feed opening, with at least one of the Chamber leading pipe in which at least one breakthrough is arranged and which forms a circuit with the chamber, with at least one heating system for heating the chamber, wherein the pipe is connected to the heating system via a heat exchanger, and with at least one circulation device, and a device for Drying of goods, in particular of wood or wood products, comprising at least one chamber provided with at least one closure opening closable with a closure means, with at least one pipe leading out of the chamber, in which at least one opening is arranged and which is arranged with d he chamber forms a circuit with at least one heating system for heating the chamber, wherein the pipe is connected to the heating system via a heat exchanger, and with at least one circulating device, in particular for carrying out the method.

In order to be able to use wood efficiently for thermal recycling, it is necessary to dry it from the impact moisture to a value of approx. 10 to 25% wood moisture. If the drying takes place naturally or in the air, this wood moisture sets in only after about 2 years, so it makes sense to carry out this drying technically. Previous known wood drying processes take about 10 to 15 days.

From the AT 409 184 B a method and apparatus for wood drying is known in which the wood is heated in a treatment room to a temperature of about 100 ° C and the resulting gases are discharged from the treatment room. In order to achieve a comparatively high degree of efficiency and to largely avoid odor nuisance of the environment, the gases in this process are supplied to a heating system above a predeterminable treatment temperature above approximately 150 ° C. and burnt. This method is aimed in particular at a thermal utilization of the resulting wood gases and wood by-products, wherein the drying time could not be significantly reduced compared to other methods known from the prior art.

Also in the DE 31 09 461 C2 a method and apparatus for high-temperature drying of wood is presented. The dehumidification takes place in at least two stages (preheating step, one or more drying steps) and takes place partly at temperatures above 100 ° C in front of him. A compression of the wood surface is thereby largely prevented by the introduction of steam during the drying phase and the drying is thereby shortened.

It is the object of the present invention to provide a method and an apparatus for economical wood drying.

This object of the invention is achieved in each case independently that the drying is carried out by the leadership of a gaseous dry medium, in particular heated air in the cycle formed by the pipe and the chamber, wherein the dry medium for the duration of drying, at least substantially not replaced is and only a maximum amount of water vapor is removed, which is formed during the drying process from the wood, further characterized in that in the heating system as the heat transfer medium, a thermal oil is used, which is a glycol or glycol contains and in that in the pipeline a drying medium is guided, wherein the chamber with the pipeline via at least one first connection, in particular for the supply of the dry medium, at least approximately in the region below the material to be dried and at least one further connection, in particular for the removal of the dry medium from the chamber, at least at approaching in the area above the material to be dried fluidly connected.

Surprisingly, it has been shown in the method according to the invention that the cycle time for drying the wood can be reduced by the circulation of the dry medium and thus the energy consumption for wood drying accordingly decreases. Furthermore, it is thus also possible to avoid the previous difficulties in the wood drying, in particular the casing at least approximately without additional steam must be supplied. In addition, the structure of the drying device is technically simple, whereby the frequency of disturbances can be reduced. This simplified structure also allows a compact design of this device, so that the space requirement is essentially determined by the size of the chamber, ie from the need for drying good. In addition, a possible odor nuisance of residents is largely avoidable, since essentially no gases or wood components can escape from the circulation.

It is also possible that the dry medium with at least approximately 90%, in particular at least approximately 80%, preferably at least approximately 70%, saturation with water or water vapor at least for the period after reaching saturation due to the drying until the termination of drying at a predeterminable degree of drying of the material is recycled, which surprisingly reduces the time required for drying, in particular to a time period of the order of one day.

The transfer of heat from the heating system to the dry medium can be carried out with a heat exchange device, which is operatively connected to the heating system via a primary heat cycle. It can thus the heat supply or the respective amount of heat required the particular circumstances or each to be dried Good and be adapted to the drying progress, without the power output of the heating system is subject to greater fluctuations, whereby the components of the heating system while still satisfactory energy balance possible be spared.

Especially in the boiler sector, it is advantageous that the thermal oil is circulated in the primary heat cycle as the heat transfer medium. The thermal oil boiler are characterized in particular by the fact that they are usually performed in the unpressurized area and therefore not subject to the Austrian Pressure Equipment Supervision Ordinance (DGÜW-V), whereby the operating costs can be reduced accordingly, or the operation of the system can also be performed by personnel who no special training for this purpose - apart from the instructions of the drying device - needs.

Advantageously, the wood having a length selected from a range with a lower limit of 0.1 cm and an upper limit of 100 cm, in particular from a range with a lower limit of 1 cm and an upper limit of 50 cm, preferably be used from a range with a lower limit of 24 cm and an upper limit of 33 cm. Thus, it is possible to use logs for applications of half-meter failure, One-third of a meter and a quarter of a meter (which covers the main needs of firewood) for virtually every wood burning plant to dry economically.

It may further be provided that the gases and / or condensates, in particular water vapor, hydrogen, phenols, alcohols, acetic acid, formic acid, carbon monoxide, which are formed in the chamber during drying, are used at least partially for heating the installation in order to reduce the energy costs ,

It is advantageous that the heat not consumed during drying in the chamber is at least partially returned to the system. Thus, e.g. In about 30 to 50% of the process heat of a drying process are returned to the subsequent process, whereby a saving in the consumption of heating materials or fuels for the heating system can be achieved.

It is also advantageous in the process according to the invention if the drying is carried out in one stage. It eliminates a possible pre-drying step, which would consume additional energy.

It is also possible that the drying is carried out at least partially under pressure. Depending on the process step, the drying can be carried out at least partially under a pressure selected from a range with a lower limit of 0 mbar and an upper limit of 2,000 mbar, in particular from a range with a lower limit of 1,000 mbar and an upper limit of 1,800 mbar, preferably from a range with a lower limit of 1,100 mbar and an upper limit of 1,500 mbar. By guiding the drying process in the overpressure, even slightly soluble components can be dried out of the dry material.

It is advantageous if the drying is carried out at least temporarily at a temperature which is selected from a range with a lower limit of 100 ° C and an upper limit of 170 ° C, in particular from a range with a lower limit of 105 ° C and an upper limit of 150 ° C, preferably from a range with a lower limit of 110 ° C and an upper limit of 128 ° C. In this temperature range is the possibility, on the one hand the drying economically from the heating temperatures and on the other hand, economically from the time spent for the drying to perform. In addition, the water absorption capacity of the dry medium at these temperatures is greater, which not only the drying time can be shortened, but also positive effects can be achieved to prevent cracking.

According to a development it is provided that the drying is carried out to a relative humidity of the goods to be dried, which is selected from a range with a lower limit of 0% and an upper limit of 50%, in particular from a range with a lower limit of 10% and an upper limit of 30%, preferably from a range with a lower limit of 18% and an upper limit of 23%. The resulting dried wood can be properly thermally recycled and thus complies with ÖNORM M 7132 regarding the use of wood and bark for energy purposes as a fuel.

It is also possible that the drying is carried out by supplying a warm, in particular hot air flow into the chamber. This feeding of the dry medium into the chamber is carried out in a preferred embodiment in an area which is at least approximately below the goods to be dried. Thus, a gentle drying by convection can be achieved, in which the drying medium with optionally reduced speed at at least approximately every point in the chamber where the dry material used is placed sweeps past.

Another possibility is that the operation, in particular the charging and / or emptying, the chamber with the goods to be dried, with a programmable feeding device, in particular with a robot, can be performed. An automated feed has the advantage that such a drying device can be driven substantially around the clock and thus large quantities of dried wood can be available in a relatively short time.

It is provided in a development that firing and / or firewood is dried. In particular, oak logs or beech logs may be dried according to the method described. The demand for good, dry beech firewood is steadily increasing due to increased environmental and cost awareness of consumers, this one Raw material is also available in sufficient quantities. Likewise, oak firewood is in high demand due to its high calorific value. Both woods are also produced in sufficient quantities in the course of thinning and / or valuable wood production and can thus be supplied within a short time of thermal utilization, usually the house fire.

It is also advantageous that wood pieces, in particular pieces of wood in bark, can be dried. The time-consuming step of bark or Borkenentfernung can be omitted so; As a result, dry wood is easier to handle, especially to split, than fresh.

Within a period of 12 hours, in particular 10 hours, preferably 8 hours, at least 60%, in particular at least 70%, preferably at least 80%, of the moisture to be dried of the wood can be removed, whereby a further control option for the drying can be given.

In a variant, it is provided that a flow direction of the dry medium is reversed at predeterminable time intervals. Thus, a largely homogeneous drying of the contents of the drying chamber can be achieved and this can be controlled by sensors in the wood.

The dry medium can also be guided through the chamber while avoiding straight-line flow channels, as a result of which an increased back pressure is exerted on the dry material and the drying efficiency can be further increased.

According to a variant of the device, it is possible for at least one deflecting plate to be arranged in the chamber in the area of the first connection, wherein according to a variant embodiment this deflecting plate may have at least one opening. The baffle can also be designed as a perforated plate. A channeling or targeted steering of the dry medium, in particular the air flow, and the largest possible distribution in the chamber is thus possible.

It is also possible that in the chamber after a junction of the pipe into the chamber at least one support device can be arranged to the spaced apart from the mouth holder of the wood. At this support device can at least one breakthrough to Can be arranged guide the dry medium, which is in particular facing away from a support surface of the support device for the wood. As a result, the most uniform possible distribution of the dry medium and thus a uniform drying can be achieved, it comes not or hardly to different drying processes, which in turn can increase the efficiency of the device according to the invention.

The support device may have a triangular cross section, but also be shaped in particular as an I or T carrier. Any other form that favors a uniform flow of dry material with the dry medium can be used here.

It can further be provided that at least one supply channel is arranged in the chamber below a receptacle for the material to be dried, into which the first connection opens. It can also be provided that at least one discharge channel is arranged in the chamber above the material to be dried, into which the further connection opens. Through this design, a uniform ventilation and thus drying of the entire dry material is possible.

In an advantageous manner, the supply channel and / or the discharge channel can have at least two flow connections into an interior of the chamber in which the material to be dried is arranged in order to split the dry medium into at least two partial streams and, as a consequence, to further homogenize the supply of the product To reach dry medium.

As a further variant, at least individual side walls of the feed channel and / or the discharge channel are at least partially formed as a perforated plate. These channels or side walls ensure a uniform flow through the drying device.

It can also be provided that the heating system is designed as a boiler for burning substances, wherein the substances are selected from a group comprising oil, fuel oil, vegetable oil methyl ester, gas, natural gas, wood, wood products, pellets, wood chips, wood by-products, bark and straw. In this rich selection of potential fuels is a very economical and future-oriented form of heat recovery and can thus be used as universally as possible heating system.

It is also advantageous that for monitoring and / or control at least one control and / or control device, in particular a data processing system, a PC, is arranged. Thus, records of the drying operations can be kept or optimizations in the field of plant can be easily and quickly carried out and is therefore also a far-reaching control of the drying process possible and possibly an automation of the drying process.

Furthermore, it is possible for at least one solar collector and / or solar module and / or wind turbine to be arranged for at least partial energy supply. Any economic subsidies for the operation of future-oriented, environmentally friendly energy production plants can also be used - depending on the state legislation - so that drying can be implemented more easily in scattered areas and more economical access to fuel could be achieved. In addition, a reduction of the pollutant emissions of the heating system can be achieved or the device can also be operated in exposed areas in which a supply of conventional fuels is difficult to carry out.

It may also be advantageous that at least one heat exchanger, in particular a fin heat exchanger, is arranged in the circuit of the pipeline. With the help of this heat exchanger is at least partially, efficient and economical use of the drying process not or not fully consumed energy, especially the heat energy, possible or can thus efficient transfer of heat energy from the heating system associated primary circuit to the dry medium in the secondary circuit due to the large surface available for heat exchange. It is thus a faster heat transfer possible, which can achieve positive effects on the drying time.

According to a development it can be provided that at least one probe, in particular a lambda probe, is arranged in the opening of the pipeline. In this way, gas contents or gas compositions in the drying medium can be measured efficiently and comprehensibly. Of particular interest here is the measurement of the O ₂ content, because it provides information about the course of the drying and can be used as a reference value for the control of the plant.

It may also be advantageous that at least one heat storage, in particular a hot water storage and / or a hot oil storage, is assigned to the heating system. Thus, peaks in the heat load distribution can be collected efficiently or process waste heat can be sensibly buffered.

A variant provides that at least two sensors are arranged in the chamber for detecting the temperature in the chamber, in particular in an upper and lower region of the chamber. At least one, in particular two, sensors for detecting the moisture in the chamber and / or in the wood can also be arranged. Furthermore, at least one measuring sensor for detecting the pressure, in particular a back pressure, can be arranged in the chamber in the chamber. Likewise, at least one sensor for detecting the temperature and / or humidity could be arranged in each corner of the chamber and in the center of the chamber. Finally, these sensors can be conductively connected to the control and / or control device, for example to perform a control or regulation of the drying process on the internal pressure. For example, more moisture can be removed from the system when the pressure is increased.

These sensors can either be designed as combined sensors, which detect both measurement parameters, or as separate sensors for detecting the temperature or the air humidity, in which case two sensors can be arranged at each measuring point of the chamber. These probes can be used to document a more precise drying process and to react immediately to any problems in the system or to irregularities in the drying process. The data collection is also well suited for studies, especially for long-term studies, thanks to a time recording system. In addition, thus an automatic control and / or control of the device depending on the respective degree of drying is possible, which may under certain circumstances, the energy requirements for the heating system in the period shortly before the termination of the drying can be reduced.

The chamber may be formed in a favorable development as a flow chamber, wherein at least two closure devices can be arranged on the flow chamber. This makes possible an efficient and economical feeding process, especially when large quantities of wood are to be dried. Once pieces of wood Once the product has dried, the load no longer has to be maneuvered back out of the chamber with difficulty, but it can be carried out at the same time the application of the already dried wood from the chamber with a new load of dry material.

Finally, the device may be mobile, in particular at least approximately container-like and / or provided with wheels. An economical wood drying directly at the seizure of large amounts of wood is thus possible.

For a better understanding of the invention, this will be explained in more detail below with reference to the embodiments illustrated in the drawings.

Fig. 1

das Grundschema einer erfindungsgemäßen Vorrichtung zum Trocknen von Gütern;

Fig. 2

den Querschnitt einer erfindungsgemäßen Trocknungsvorrichtung mit einer angeordneten Heizanlage und einer Steuereinrichtung.

In a very schematically simplified representation:

Fig. 1

the basic scheme of a device according to the invention for drying goods;

Fig. 2

the cross section of a drying device according to the invention with an arranged heating system and a control device.

By way of introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numerals or the same component names, wherein the disclosures contained in the entire description can be mutatis mutandis to the same parts with the same reference numerals or component names. Also, the location information chosen in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and are to be transferred to the new situation mutatis mutandis when a change in position. Furthermore, individual features or combinations of features from the different exemplary embodiments shown and described can also represent independent, inventive or inventive solutions.

All information on ranges of values in objective description should be understood to include these arbitrary and all sub-ranges thereof, eg the indication 1 to 10 is to be understood such that all sub-ranges, starting from the lower limit 1 and the upper limit 10, are included. ie all subareas begin with a lower one Limit of 1 or greater and end at an upper limit of 10 or less, eg 1 to 1.7, or 3.2 to 8.1 or 5.5 to 10.

From FIGS. 1 and 2, various embodiments of a device 1 according to the invention can be seen. Such a system 2 consists of a chamber 3, which is designed as a drying chamber. The chamber 3 has at least one charging opening 4, which can be closed with a closure device 5 (see FIG. 2).

In a preferred embodiment of the invention, the chamber 3 has an internal volume, that is to say a volume which is available for the charging of goods to be dried, which has a size of approximately 2 m ³ to 5 m ³ , preferably 3 m ³ , Within the scope of the teaching of the invention, however, this volume may also be less than 2 m ³ or greater than 5 m ³ .

Due to the resistance to an internal pressure above atmospheric pressure, the chamber 3 can ideally be designed in a greater wall thickness (material thickness ≥ 10 mm), with metals or metallic alloys in particular being used as materials for the wall. To achieve a higher dimensional stability, any reinforcing elements, such as, for example, on the inner and / or outer sides, may be used. Reinforcing ribs be attached.

In the event that the device 1 is operated at a pressure in the order of the atmospheric pressure, this wall thickness can also be made smaller. The dimensioning of the wall thickness lies in the expertise of the skilled person.

The walls of the chamber 3 may be filled with insulation 6 (Figure 2) to ensure a more efficient thermal management in the device 1 during drying.

The material to be dried can in particular be a wood 7, can be introduced into the chamber 3 in a loose, ordered, poured or other suitable form, it being important to ensure that between the components of the wood 7, for example, the logs or the boards , Space for free air circulation is present. If it is Scheiter, then the spaces between the individual pieces of wood are sufficient for a good ventilation and it is not necessary to use separate spacers. For a good invention Drying action must be taken to ensure that there are as far as possible no through channels in the dry material, which could cause an irregular drying result. With a uniform flow, a higher dynamic pressure is exerted on the dry material, which can positively influence the drying.

For loading the chamber 3, a trackless forklift, in particular a forklift, can preferably be used, whereby also hand stackers (so-called "ants"), cranes, tongs, tractors, loaders, other suitable conveying devices or partially or fully automated loading devices, such as e.g. Robot, can be used.

In the upper region of the chamber 3 there is a discharge channel 8, which is connected to a connection 9 with the interior of the chamber 3. This discharge channel 8 is used for the withdrawal of saturated, in particular heated, air or other gaseous dry medium 10. The dry medium 10 rises through the discharge channel 8 to a circulating device 11 as a result of the effect of the same, then flows through a pipe 12, in this Embodiment also forms the discharge channel 8, further to a heat exchanger 13, where the dry medium 10 heat is lost to the dry medium 10 due to drying or other causes, is returned to keep the drying medium 10 to operating temperature. A cleaning of the dry medium 10, in particular of wood and wood 7 condensates or wood components, can take place here or immediately after the heat exchanger 13, to which optionally separate, not shown, cleaning devices, e.g. Gas scrubber, fluidly connected to the pipe 12 may be arranged in the device 1.

The heat exchanger 13 is supplied via a not shown circuit from a heating system 14, the heat required for the drying process.

The power of the circulation device 11 can be regulated or controlled as a function of the residual oxygen content and / or the temperature profile in the chamber 3.

It is within the scope of the invention also possible to promote the dry medium directly through the heating system 14, to which the pipe 12 may be guided by the heating system 14.

The heating system 14 is preferably designed with a thermal oil boiler, it being possible to use a glycol, in particular a propylene glycol, as the thermo-oil. As energy sources for the heating system 14, conventional fuels such as e.g. Oil, fuel oil, vegetable oil methyl ester, gas, natural gas, wood, wood products, pellets, wood chips, wood by-products, bark, straw in question, as well as renewable energy sources such as solar or wind energy, photovoltaic, geothermal or in the drying of wood 7 resulting side or waste products such as gases and / or condensates, in particular water vapor, hydrogen, phenols, alcohols, acetic acid, formic acid, carbon monoxide, are used to provide at least part of the required energy.

Also fluidly connected to the pipeline 12 via a further pipeline may be a condenser 32 which dissipates at most that amount of water vapor which is formed in the wood 7 during the drying process. It can also be withdrawn less or no water. For deriving the condensate, the capacitor 32 may have a derivative, at the end of a vessel such. As a shell, a measuring cup or similar suitable container may be located. The condensate can also be fed directly via at least one line of a recovery, for example, a thermal utilization to support the heat energy recovery.

It can also be provided, as shown in FIG. 2, that heat from heated thermal oil 16 is transferred to the drying medium 10 in the heating system 14 by means of a heat exchange device 15. By a primary circuit 17, the thermal oil 16 can be heated to temperatures in the range of up to 400 ° C and gives this in the heat exchange device 15 a portion of the heat - controllable by a separate control device on or in the heating system 14 or externally - to the Drying medium 10 from.

The thus-heated drying medium 10 continues to flow through the pipeline 12, to be returned to the chamber 3 through a lower port 18 of the chamber 3 which is connected to a supply channel 19, which in this embodiment is again formed by the pipe 12.

According to one embodiment of the invention, as shown in Fig. 1, in the chamber 3, the warm air flow or the dry medium 12 by a baffle 20, the at least one opening 21 may have (in Fig. 1, 5 openings 21 are shown) are directed to the wood 7. The baffle 20 may be made of a metallic material, which is particularly viable, mechanically durable and corrosion resistant to heat, moisture and the partially aggressive wood ingredients designed to order the material to be dried directly on it. The baffle 20 may be designed in particular as a perforated plate, but also as a grid-like element, or other suitable device.

But it can also be arranged in the chamber 3 another intermediate floor to carry the material to be dried. On this intermediate floor support devices 30 may be located, which are carrier-shaped, in particular I- or T-carrier-shaped, pitched roof-shaped, triangular, arrow-shaped, round, polygonal or formed in any other suitable form. There may be breakthroughs 31, in particular outflow openings, for the drying medium 10 in each case closer to the feed channels end of the support devices 30. In the representational Fig. 2 saddle-shaped and T-beam-shaped support devices are shown for illustration, with one or more forms of support devices 30 may be used depending on the embodiment.

A similar design of the deflecting plate 20 is also conceivable, wherein supporting elements can be arranged directly on the deflecting plate 20 and, as described above, can have openings for passage of the dry medium 10.

It is further also possible to dispense with the baffle 20, which may be designed as a perforated plate, and to supply the dry medium 10 directly into the interior of the chamber 3. The deflection plate 20 or the deflection device with which the flow pattern of the dry medium 10 can be changed, however, has the advantage that it allows a better distribution of the dry medium 10 in the chamber 3 can be achieved, which can be achieved corresponding advantages on the drying process.

The deflection can instead of the execution of at least over a majority of the width of the interior of the chamber extending and thus a separate, different from the pipe 12 supply channel 19 forming, be designed as a smaller component to the dry medium flow only at least approximately in the direction of the dried Good to judge. For example, it is possible for these baffles 20 - it can also be present several to specify a certain flow path, which is advantageous for drying - as projections of the inner wall of the chamber 3 - for example, integrally formed from these - form or separate sheets to install the inner wall, in particular to be welded to this. For example, these baffles 20 may be formed in the form of shaped sheets, eg blade-shaped, hook-shaped, triangular, etc.

It should be mentioned at this point that even in the upper region of the chamber 3, ie above the material to be dried, a separate, different from the pipe 12, discharge channel 8 may be formed as a collecting channel for the dry medium 10, for example, again by arranging a perforated plate , It is also possible in this area instead of the perforated plate or in addition, as is also possible below the material to be dried, deflection devices, e.g. to arrange at least one baffle 20.

The baffles 20 may have at least one opening 21.

The wood 7 is preferably gently and effectively dried in cooperation with the flow rate of the dry medium 10, optionally the arrangement of the apertures 21 and of the baffle (s) 20, as well as the temperature of the dry medium 10 matched to the respective dry matter.

Within the chamber 3, at least one sensor 22 may be arranged. As can be seen from FIG. 2, a sensor 22 can be arranged in each corner of the chamber 3 as well as in the center of the chamber. Additional additional sensors in planes between the center and the corners of the chamber 3 are also possible if required. In order to obtain informative data about the drying process, one, some or all measuring sensors 22 can also be introduced directly into the dry material, in particular into the wood 7.

The temperature and / or the humidity and / or the pressure in the chamber 3 are monitored or measured with these sensors 22, and the measurement result can be based on a control and / or control process, eg the temperature and / or the pressure, be.

The sensors 22 may be designed according to the desired functionality according to the prior art, and are preferably made of suitable for use in the heat and moisture-exposed area materials. For example, screws may be placed as probes 22 approximately in the middle of the wood 7 or of pieces of wood, but other materials such as pins, nails, wires, electrodes, sensors, measuring devices, use fmden.

Some or all of these sensors 22 may be line connected to a data processing system 24 via a line 23. Optimizing the drying process is therefore also possible during a running drying process, it is also possible to carry out longer measurement records or to run test series for drying.

It is of particular interest to use for the drying of different types of wood, in particular of beech and oak, as well as wood other than firewood, e.g. Ash, other hardwoods, spruce, other softwoods, various dry processes, especially to determine drying programs. Thus, the wood 7 can be dried in an economical manner according to its wood species-specific physiological properties. These data are preferably stored in a data memory, so that they are available as a basis for further drying processes and thus the device 1 can optionally be operated fully automatically.

The values measured by the probe (s) 22 may also be used to open or close the chamber 3. Thus, e.g. the closure device 5 are automatically opened after reaching a predetermined target final moisture content of the wood 7, for example 20%, and the end of a drying process is initiated.

Another possibility for optimization or control is given by a probe 25, which is located in an opening 26 of the pipe 12. This probe 25 can be designed in particular as a lambda probe and should specifically measure the oxygen content in the dry medium 10. With this feedback manual or automatic adjustments can be made in the respective drying process if required. It is also possible to arrange a plurality of possibly different probes 25 in the pipeline 12.

By means of the lambda probe, it is possible to indirectly deduce the water vapor content in the dry medium 10 by determining the oxygen content in the dry medium 10. For this purpose, a value of 0% oxygen can be interpreted as at least approximately 100% water vapor.

In practical testing of the invention it has been found that it may be better to carry out the drying with a certain residual oxygen content. The residual oxygen content may be selected from a range with a lower limit of 4% and an upper limit of 20%, in particular a lower limit of 8% and an upper limit of 12% to 14%. This result is surprising in that a higher water vapor content should be better per se, since the energy transfer to the wood to be dried via the water vapor. However, in view of the shortening of the drying time, it may be advantageous if in the initial phase of drying with almost 100% water vapor content in the dry medium 10 is used to allow a rapid increase in temperature, again due to the better heat transfer through the water vapor. This procedure can be carried out up to a temperature of 100 ° C to 110 ° C, and then (over 100 ° C to 110 ° C) the water vapor content of the dry medium 10 is lowered to adjust the above residual oxygen content, for example by condensation and removal of part of the Steam from the system. The thus set dry medium 10 can absorb water from the wood better.

It can be made with this procedure, a dynamic control with controlled Wasserentfemung or addition from or into the system, which can be used as a factor of resistance of the wood against the water release. The resistance of the wood can be done via one or more electrode (s), which is introduced into the wood or be. The, preferably regulated, removal of water vapor from the system can also take place at least partially via a condensate outlet of the chamber 3.

In order to keep the oxygen content at a certain level, it is possible to introduce water into the system, for example to dust it. Maintaining a specific water vapor saturation improves energy transfer.

In other words, it is beneficial for the dry course when in the chamber 3 a specific climate is set.

With the dynamic control or regulation, a drying time within 9 to 19 hours is possible.

Instead of the lambda probe, a hygrometer can also be used.

By determining the degree of saturation of water vapor, it is possible to make the control or regulation of the drying process dynamically by water vapor is removed from the system depending on the degree of saturation or additionally water or steam is dusted. The atomization is preferably carried out after the heat exchanger (viewed in the flow direction of the dry medium 10). Likewise, the removal of water vapor preferably take place after the heat exchanger in order to exploit its energy content can still.

The dynamic control or regulation of the water vapor saturation is preferably carried out in the temperature range below 100 ° C, in particular after a preferred rapid warm-up of the system.

By measuring the degree of water vapor saturation, it is possible to deduce a possible casing of the wood, ie the closing of the pores of the wood, or at what point in time the pores open. The cladding should be avoided as much as possible, since closed pores prevent the evaporation of water.

As the embodiment of FIG. 2 shows, deflecting devices 27 can be arranged in one corner or in several or all corners of the chamber 3 for improved circulation or flow of the dry medium. Preferred materials for these deflection devices 27 are sheets of metals and / or metal alloys and plastics, wherein a corrosion-resistant design due to the high thermal load and the moisture exposure is advantageous. These deflection devices 27 can be welded, screwed, riveted, soldered, glued or connected in any other suitable manner with the inner wall of the chamber 3.

The circulation rate of the dry medium 10 is determined by the circulation device 11. An increase in the flow rate of the dry medium 10 may cause an acceleration of the drying process per se, but it may also be that in the case of a fault, breakdown or an unexpectedly high accumulation of gases or wood by-products, a slowing of the flow velocity to be achieved. The heat exchanger 13 can thus also work predominantly in the optimum range and is exposed to only a few working peaks, which would increase the wear and reduce the service life.

In order to control the circulation device 11, it may be provided to use data from the measuring sensors 22 for this purpose. Thus, it is possible for a measured temperature stratification in the chamber 3 or for temperature differences of individual measuring points to a predeterminable extent, for example in a range of 1 ° C to 10 ° C, in particular in a range of 2 ° C to 5 ° C, the start of the circulation device 11 is initiated in order to achieve the most uniform possible drying result. It has proven to be particularly efficient when the fan insert is started at a temperature difference (Δt) of 3 ° C.

As limiting factors in this type of wood drying on the one hand, the speed at which open the pores of the dry material and on the other hand, the temperature in the wood 7. The faster a pore opening and thus an evaporation of moisture from the wood 7 is going on, the faster a desired predeterminable moisture content or dry state can be achieved.

Since evaporation of moisture from wood 7 during treatment in the device 1 according to the invention is primarily carried out via the medullary rays, tearing, casing can be at least partially prevented.

In a preferred embodiment, the oxygen level in the system is close to 0%, that is, there is no free oxygen present. In some cases, oxidative processes in the dry material, in particular in the wood 7, can also take place.

In order to achieve an improvement in the drying efficiency, if necessary, a cross exchanger be arranged, which at least partially reverses the flow of the dry medium 10, that is, that at predetermined intervals, the flow direction is changed. These intervals can be, for example, 10 to 60 minutes or, depending on the requirement or measurement results, be dimensioned from the sensors 22. Mostly, however, the dry material will be flowed through with the dry medium 10 from bottom to top.

It is also possible that the dry medium 10 is introduced both below and above in the chamber 3 and approximately at half the height of the chamber 3 is discharged again.

It can also be advantageous with regard to the acceleration of the drying if the chamber has a greater length and / or width compared to its height.

It has been found that at drying temperatures above 100 ° C., decomposition processes take place in the wood 7, which can cause a color change in the dry material (for example, spruce can become more yellowish, beech can become darker or more colorful). These effects can be used on the one hand in the at least partial use of wood as a floor covering, parquet in particular, in the furniture production or other Tischlermäßigen applications or these are even desirable.

On the other hand, these degradation processes reduce the nutrient content of pests, insect pests or wood-degrading and / or wood-destroying organisms - the dried wood 7 according to the invention is less interesting for pests. Moreover, since a temperature effect of at least 60 ° C irreversibly destroys the protein of pest larvae, also a new case is largely prevented. Thus, the demand for largely pest- or insect-free firewood can be met, which, especially in the urban area with limited storage facilities of fuel outside the living area, is large. A storage of firewood or firewood directly in the apartment can be made easier because also the subsequent infestation with pests, e.g. with wooden goats, anobia, beetle beetles, wood wasps, can be largely prevented. Also in the marketing of such dried fuels can be addressed specifically on this advantage.

In previously known drying chambers had around these plants enough space for Store the goods to be dried, remove the dried material, shuffle and sort after inconsistent drying. Therefore, it is provided in a particularly advantageous embodiment that the system 2 can also be used for mobile use, thus ensuring transportability of the device 1 to the respective place of seizure of wood to be dried. This is made possible by the compact feasibility of the device 1, which in its minimal version requires only a few components.

On the outside of the chamber 3, instead of the supply channel 19 or the discharge channel 8, connections (not shown) for an external heat and energy supply on site in the form of a so-called "docking station" can be arranged for this purpose.

As a variant could be at the bottom of the device 1 wheels 29 or other suitable means of transport such as rollers, skids, planks, slides, which allow easy transport to the desired location. Likewise, at the top of the plant 2, one or more hitch (s), such as hooks, eyes, loops, rings, conceivable to which ropes, straps or similar lifting equipment can be attached. The locomotion of the device 1 can thus go through a crane, an excavator or any other suitable vehicle.

A process that is as economical as possible for obtaining dry firewood could proceed so that the wood 7 is filled into the chamber 3 directly at the point of seizure, for example in the case of a log splitter, processor, PTO splitter, a separating device or the like. The chamber 3 can be expediently designed as a roll-off, Absetz-, WAP or other container, the size of the transport options (truck-mobile or tractor-driven) is influenced. Subsequently, the chamber 3 can be brought to the drying place, where after drying the removal of the dry material, e.g. by dumping or further emptying operations, can be made. Any intermediate storage of the dried wood 7 or the packaging into marketable units completes the process.

The embodiments show possible embodiments of the method, it being noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but rather also various combinations of the individual embodiments are mutually possible and this variation possibility due to the doctrine of technical action by objective invention in the skill of those skilled in this technical field. There are therefore also all possible embodiments, which are possible by combinations of individual details of the illustrated and described embodiment, the scope of protection.

For the sake of order, it should finally be pointed out that, for a better understanding of the structure of the method, this or its constituent parts have been shown partly out of scale and / or enlarged and / or reduced in size.

The problem underlying the independent inventive solutions can be taken from the description.

Above all, the individual in FIG. 1; 2 embodiments form the subject of independent solutions according to the invention. The relevant objects and solutions according to the invention can be found in the detailed description of this figure.

REFERENCE NUMBERS

1

contraption

2

investment

3

chamber

4

loading port

5

closure device

6

insulation

7

Wood

8th

discharge channel

9

connection

10

dry medium

11

circulation

12

pipeline

13

heat exchangers

14

heating system

15

Heat exchange device

16

thermal oil

17

Primary circuit

18

connection

19

supply channel

20

baffle

21

breakthrough

22

probe

23

management

24

Data processing system

25

probe

26

breakthrough

27

deflecting

28

opening

29

bikes

30

support device

31

breakthrough

32

capacitor

Claims (30)

Method for drying goods, in particular wood (7) or wood products, preferably oak logs or beech logs or pieces of wood, in particular pieces of wood in bark, in which the goods are dried in a plant (2) which has at least one chamber (3 ), which is provided with at least one, with a closure means (5) closable feed opening (4) with at least one of the chamber (3) leading pipe (12) in the at least one opening (26) is arranged and with the Chamber (3) forms a circuit, with at least one heating system (14) for heating the chamber (3), wherein the pipe (12) with the heating system (14) via a heat exchanger (13) is connected, and with at least one circulating device ( 11), characterized in that the drying by the guide of a gaseous drying medium (10), in particular heated air, (in which (through conduit 12) and the chamber 3) formed circuit carried wherein said drying medium (10) is not exchanged for the duration of the drying is at least substantially and is discharged a maximum of only that amount of water vapor during the drying process from the timber (7) is formed is hrt. Method for drying goods, in particular wood (7) or wood products, preferably oak logs or beech logs or pieces of wood, in particular pieces of wood in bark, in which the goods are dried in a plant (2) which has at least one chamber (3 ), which is provided with at least one, with a closure means (5) closable feed opening (4) with at least one of the chamber (3) leading pipe (12) in the at least one opening (26) is arranged and with the Chamber (3) forms an at least approximately closed circuit, with at least one heating system (14) for heating the chamber (3), wherein the chamber (3) with the heating system (14) through the pipe (12) is connected, and at least a circulating device (11), in particular according to claim 1, characterized in that in the heating system (14) as a heat transfer medium, a thermal oil (16) is used, which is a glycol or contains glycol. A method according to claim 1 or 2, characterized in that the drying medium (10) with at least approximately 90%, in particular at least approximately 80%, preferably at least approximately 70%, saturation with water or water vapor at least for the time interval after reaching saturation due to drying until termination of drying at a predeterminable degree of drying of the material is circulated. Method according to one of claims 1 to 3, characterized in that the wood (7) with a length selected from a range with a lower limit of 0.1 cm and an upper limit of 100 cm, in particular from an area with a lower limit of 1 cm and an upper limit of 50 cm, preferably from a range with a lower limit of 24 cm and an upper limit of 33 cm is used. Method according to one of claims 1 to 4, characterized in that the drying is carried out at least partially under pressure. Method according to one of claims 1 to 4, characterized in that the drying is carried out at least partially under a pressure selected from a range having a lower limit of 0 mbar and an upper limit of 2,000 mbar, in particular from an area with a lower limit of 1,000 mbar and an upper limit of 1,800 mbar, preferably from a range with a lower limit of 1,100 mbar and an upper limit of 1,500 mbar. Method according to one of the preceding claims, characterized in that the drying is carried out at least temporarily, in particular in the heating phase, at a temperature which is selected from a range with a lower limit of 100 ° C and an upper limit of 170 ° C, in particular from a range with a lower limit of 105 ° C and an upper limit of 150 ° C, preferably from a range with a lower limit of 110 ° C and an upper limit of 128 ° C. Method according to one of the preceding claims, characterized in that the drying carried out to a relative humidity of the goods to be dried is selected from a range having a lower limit of 0% and an upper limit of 50%, in particular, a range having a lower limit of 10% and an upper limit of 30%, preferably a lower limit range of 18% and an upper limit of 23%. Method according to one of the preceding claims, characterized in that the drying is carried out by supplying a warm, in particular hot, air flow into the chamber (3). Method according to one of the preceding claims, characterized in that the supply of the dry medium (10) in the chamber (3) is carried out in a region which is at least approximately below and / or above the goods to be dried. Method according to one of the preceding claims, characterized in that within a period of 12 hours, in particular 10 hours, preferably 8 hours, at least 60%, in particular at least 70%, preferably at least 80%, of the moisture to be dried are removed from the wood. Method according to one of the preceding claims, characterized in that a flow direction of the dry medium (10) is reversed at predeterminable time intervals. Method according to one of the preceding claims, characterized in that the dry medium (10) is guided through the chamber (3) while avoiding straight-line flow channels. Method according to one of the preceding claims, characterized in that the drying in dependence on an oxygen radical content of the dry medium (10) and / or a temperature profile in the chamber (3) is controlled or regulated. A method according to claim 14, characterized in that the oxygen radical content of the dry medium (10) is kept at a level at least after the heating phase, with a lower limit of 4% and an upper limit of 20%, in particular a lower limit of 8% and an upper limit of 14%, oxygen content. Device (1) for drying goods, in particular wood (7) or wood products, preferably oak logs or beech logs or pieces of wood, in particular pieces of wood in bark, which has at least one chamber (3) with at least one, with a Closing device (5) closable feed opening (4) is provided with at least one of the chamber (3) leading pipe (12) in the at least one opening (26) is arranged and which forms a circuit with the chamber (3), with at least a heating system (14) for heating the chamber (3), wherein the pipe (12) with the heating system (14) via a heat exchanger (13) is connected, and with at least one circulation device (11), in particular for carrying out the method according to a of the preceding claims, characterized in that in the pipe (12) a dry medium (10) is guided, wherein the chamber (3) with the pipe (12) via at least one first connection (1 8), in particular for the supply of the dry medium (10), at least approximately in the region below the material to be dried and at least one further connection (9), in particular for the removal of the dry medium (10) from the chamber (3), at least approximately Is flow-connected above the area to be dried. Device (1) according to claim 16, characterized in that in the chamber (3) in the region of the first terminal (18) at least one deflecting plate (20) is arranged, which optionally has at least one opening (21). Apparatus according to claim 17, characterized in that the deflecting plate (20) is designed as a perforated plate. Device (1) according to one of claims 16 to 18, characterized in that in the chamber (3) after an opening of the pipe (12) into the chamber (3) at least one support device (30), in particular with triangular cross-section, is arranged to the spaced from the mouth holder of the wood (7). Device (1) according to claim 19, characterized in that in the support device (30) at least one opening (31) for guiding the dry medium (10) is arranged, in particular by a bearing surface of the supporting device (30) for the wood (7). turned away. Device (1) according to any one of claims 16 to 20, characterized in that in the chamber (3) below a receptacle for the material to be dried at least one supply channel (19) is arranged in the first port (18) opens. Device (1) according to one of claims 16 to 21, characterized in that in the chamber (3) above the material to be dried at least one discharge channel (8) is arranged in the further connection (9) opens. Device (1) according to claim 21 or 22, characterized in that the supply channel (19) and / or the discharge channel (8) has at least two flow connections in an interior of the chamber (3), in which the material to be dried is arranged. Device (1) according to one of claims 21 to 23, characterized in that the at least individual side walls of the feed channel (19) and / or discharge channel (8) are at least partially formed as a perforated plate. Device (1) according to one of claims 16 to 24, characterized in that the heating system (14) is designed as a boiler for Verfeuem of substances selected from a group comprising oil, fuel oil, vegetable oil methyl ester, gas, natural gas, wood, wood products, pellets , Wood chips, wood by-products, bark, straw. Device (1) according to one of claims 16 to 25, characterized in that in the opening (26) of the pipe (12) at least one probe (25), in particular a lambda probe, is arranged. Device (1) according to one of claims 16 to 26, characterized in that in the chamber (3) at least two sensors (22) for detecting the temperature in the chamber (3) are arranged, in particular in an upper and lower region of the chamber (3). Device (1) according to one of claims 16 to 27, characterized in that in the chamber (3) at least one, in particular two, sensor (22) for detecting the moisture in the chamber (3) and / or in the wood (7) are arranged. Device (1) according to one of claims 16 to 28, characterized in that in the chamber (3) at least one sensor (22) for detecting the pressure, in particular a back pressure, in the chamber (3) is arranged. Device (1) according to claim 28 or 29, characterized in that at least one measuring sensor (22) for detecting the temperature and / or humidity in each corner of the chamber (3) and in the chamber center, is arranged.

Images