• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
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  • 优先权
    • 专利摘要:
    Described are a system and a method for drying a wet material / bulk material, in particular biomass. The material to be dried is transported by a transport device at least partially through a drying room (1). Heated air is passed through the drying room (1) substantially along or against the transport direction of the material to be dried. The residual heat of the air, which is still present after being passed through the drying space, is returned to the system by means of at least one heat exchanger device (3), so that the energy required for drying the material is below the necessary enthalpy of enthalpy of water, and preferably below 2,200 kJ / kg , more preferably below 1500 kJ / kg, and preferably below 1000 kJ / kg. (Fig.
    公开号:AT510487A1
    申请号:T1673/2010
    申请日:2010-10-07
    公开日:2012-04-15
    发明作者:
    申请人:Mci Man Ct Innsbruck Internationale Hochschule Gmbh；
    IPC主号:
    专利说明:

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    The invention relates to a drying process and drying system, in particular a system and a corresponding method for drying a moist material such as moist bulk materials, and biomass or carbonaceous raw materials, in particular of wood chips. The system according to the invention is based in particular on a pre-drying device with a downstream drying device, wherein the material to be dried is preferably transported by means of spiral conveyors through the pre-drying device and / or drying device. Efficient heat recovery and energy coupling between the pre-dryer and the dryer provide an efficient and energy efficient system and method.
    Background of the invention
    Biogenic bulk materials such as wood chips, bark mulch or generally shredder products from forestry are increasingly being used thermally in heating plants. Due to their hydrophilic behavior, such bulk materials attract and absorb enormous amounts of water during their outdoor storage under appropriate environmental conditions. A water content up to 60% of the total mass is not uncommon. In addition to the fact that this moisture greatly accelerates the biodegradation process of the fuel (energy loss during storage), the water content must be removed or evaporated before or during the thermal utilization anyway. For example, the calorific value of wood can be reduced from 15 MJ / kg (at 18% water content) to 6 MJ / kg (at 60% water content). In addition to a deteriorated combustion behavior, which has a negative effect on the efficiency of thermal utilization - for example in Heizv / erken - affects increases with increasing proportion of water, especially the required amount of fuel.
    The technical drying of bulk solids is one of the basic processes of thermal process engineering. Belt, drum and fluidized bed dryers are able to dry large quantities of bulk goods quickly but with considerable energy input. Recirculating air dryers require small amounts of thermal energy, but are very slow and sometimes inefficient in addition to seasonal fluctuations.
    Biogenic bulk materials have a property that makes them difficult to dewater with these conventional drying methods. Their specific energy content or their calorific value per volume is so low that the high investment costs for the above-mentioned drying systems alone mean that the majority of the plants can not be operated economically. In the following, advantages and disadvantages are discussed - in view of the use for the drying of biomass - of different drying systems, which are known from the prior art.
    Belt dryers are one of the most commonly used drying concepts. The easiest way to dry well on a conveyor belt is to pass the drying air over the material. As a rule, the drying air is forced through a perforated conveyor belt, which directly implies the disadvantages of a belt dryer. If the bed is not homogeneously applied, the air will flow through that area of least resistance, resulting in inhomogeneous drying. Another disadvantage is that the drying air must be forced through the belt, which has a negative effect on the operating costs by an increased pressure loss. Due to the different water content on the dryer belt, it is conditionally possible to have specific sizes for the exhaust stream, i. indicate the airflow leaving the dryer. This explains why the exhaust stream from belt dryers typically has a relative humidity of, for example, 70%. The thennish energy requirement of belt dryers is, for example, between 3,000 and 6,000 kJ / kg of removed water (evaporation enthalpy of water at 100 ° C.: 2,250 kJ / kg of water).
    Drum dryers, in which the material is moved in a heated, rotating rotary kiln, are mainly used in large plants with a water evaporation capacity of up to 50t / h. Drum dryers are used especially in the chip processing industry, as their main applications are in the field of free-flowing, porous bulk materials. Drum dryers are less suitable for drying sticky or pasty substances, since these substances can stick to the wall of the drum dryer and thus impair the heat transfer. In real cases, an exhaust gas condensation is rarely used, the reason for this lies in the dust occupancy of the heat exchanger. The dust occupancy of the heat exchanger leads to an increased pressure loss and a deteriorated heat transfer. Real values for the specific energy requirement of a drum dryer can be quantified with 3,000-10,000kJ / kg of evaporated water.
    Due to their simple design and the low specific thermal energy consumption circulating air dryers are often used in agriculture. The material to be dried is applied to beds and flows through ambient air from below. The drying process is therefore mainly dependent on the ambient temperature, but also on humidity, bed height and amount of drying air. Especially in winter, when the largest amount of energy is needed, this system provides the lowest output and is therefore only partially suitable for technical applications.
    Screw dryers are relatively complex systems, which have a jacket heating, and often have a heating of screw conveyors. A screw conveyor is a shaft around which one or more helical gears are wound in the form of flat sheets. The most common type is a screw heat exchanger, which tempered pasty substances. The advantage of this system is that even crystallization processes in the dryer do not pose a problem. Main disadvantages are the high investment costs and high operating costs, which are caused in particular by the pressure loss in the screw.
    Fluidized bed dryers are dryers that fluidize particles by high flow rates and dry them by an intensive material and heat exchange. The main area of application lies in the chemical industry or coal dust drying and is characterized by enormous electrical expenditure on blowers for larger particles. In the biomass drying a fluidized bed drying has not yet been realized.
    In summary, one of the basic problems in drying biomass is the high enthalpy of enthalpy of water (2,250kJ / kg at 100 ° C) which has to be applied during the drying process. Although known from the prior art high-temperature drying systems are able to process large amounts of material quickly and to dry, but need a multiple of this amount of energy per kilogram of water. Due to the relatively low energy density of biomass and the comparatively high proportions of water, the complete energy of the biomass for drying would be expended for drying in such a process. To some extent the opposite to high-temperature dryers are recirculating air dryers, which manage without additional thermal energy and draw exclusively from the environment. However, this does not succeed in an efficient drying process. Especially during the cold season, the air can be loaded with little water - but in this time maximum amounts of dry fuel are needed. A high electrical energy requirement due to enormous amounts of air is the result. Current systems are unable to efficiently and economically dry biogenic bulk materials.
    An object of the invention is to provide an improved system and method for drying material, in particular bulk materials and biomass or carbonaceous raw materials, in particular, it is an object to provide a system and a corresponding method for drying, which works energy-saving the energy required for drying is preferably below the necessary enthalpy of evaporation of water. A further object of the invention is to provide an efficient, preferably favorable and integrative drying system or process, which is tailored to the requirement of these "novel" bulk goods with a relatively low calorific value.
    These objects are achieved by the features of the independent claims.
    The dependent claims relate to preferred embodiments of the invention.
    According to the invention, a system and a process for drying a liquid-containing material, in particular biomass, are provided, the process preferably having the following process steps. The liquid-containing material is conveyed by means of a transport device at least partially through a pre-drying space and / or a drying space. During transport through the pre-drying space and / or drying space, the material may preferably be turned several times. By means of a heated / heated gas - preferably air which is also carried out through the pre-drying space and / or drying space, the liquid contained in the material - preferably water - at least partially removed or removed, i. the material can be dried. The direction of passage or flow direction of the heated / heated gas stream is preferably directed counter to the transport direction of the material, but may also be rectified with the transport direction of the material.
    The pre-drying room and the drying room are preferably designed similarly.
    Thus, for example, the pre-drying space and / or the drying space may have an at least partially cylindrical drum, within which the transport device, preferably in the form of a spiral conveyor, is arranged. Unlike a screw conveyor having a worm shaft with a worm thread attached thereto, the spiral conveyor according to the invention preferably does not have a central shaft to support a spiral (" undulating conveyor coil "). In other words, the spiral conveyor is preferably formed by a self-supporting spiral or spiral or screw.
    The space in the middle of the helix is called the "soul". This construction allows gas to be passed along the soul through the helix. However, it may be advantageous to provide support structures within the core, but the support structures do not fill the entire cavity of the soul. The spiral conveyor according to the invention with " soul " has the advantage that along the geometric center axis of the spiral conveyor the heated / heated air for drying the material can be carried out unhindered, i. There may be an efficient transfer of heat from the air to the conveyed material. A support structure optionally mounted within the core should be such that gas can flow substantially along the axis of the coil, i. the support structure, unlike a shaft of a screw conveyor, should not be solid and have openings allowing gas flow. For example, a support structure could have radially arranged spokes. Similar to the auger, the helix is rotated to transport the material, i. the delivery principle preferably corresponds to that of an Archimedean screw.
    According to a preferred embodiment, the pre-drying space and / or drying space itself is formed as a cylindrical drum, oval-shaped tube or pipe with an at least partially (circular) arcuate cross-section, in the interior of which a rotating spiral conveyor the material from a material entry to transported a material discharge. Preferably, at least at the bottom, the tube or drum has a (circular) arcuate cross-section substantially corresponding in shape and size to the arcuate shape of the rotating spiral conveyor to ensure effective transport of the material.
    Preferably, additional turning devices are attached to the spiral conveyor with the core, whereby the material to be dried can be turned inside the pre-drying room and / or the drying room. For example, blades on the spiral conveyor can accelerate mixing.
    The preferred spiral conveyor system of the present invention is somewhat similar to a drum drying system. However, a significant difference is that not the whole drum rotates, but preferably only the spiral conveyor, and preferably not the drum. *** " As a result, a significantly cheaper (pre-) dryer can be realized, whose own energy consumption is significantly reduced.
    After passing the heated / heated gas through the drying space, the " residual energy " by means of at least one heat transfer device / heat exchanger device - preferably a condenser - returned to the inventive system. For example, the recovered energy may be used to preheat the above gas stream, with the preheated gas stream subsequently being further heated and thereafter passed through the drying space, and / or used to heat a pre-drying gas stream. The energy requirement for drying the material (hereinafter also referred to as "good") can be achieved by the efficient energy recovery below the necessary enthalpy of enthalpy of water, and preferably below 2.200 kJ / kg, more preferably below 1.500 kJ / kg and preferably below 1000 kJ / kg are pressed.
    The inventive system is preferably referred to as " low temperature dryer " formed, that is, the temperature of the heated gas, which is introduced into the drying space (hereinafter also referred to simply as drying air), is preferably between 80 ° -240 ° C. Preferably, the drying air is not above the ignition temperature of the material to be dried. Thus, according to a preferred embodiment, the drying air with the usual flow and return temperatures of heating plants or combined heat and power plants (CHP plant) are heated, i. to temperatures between about 70-110 ° C. That the relatively low temperatures can be used effectively in the system according to the invention for the drying of biomass.
    Based on this preferred low-temperature concept, it is also possible, in particular by selecting specific inlet and outlet temperature levels, preferably in conjunction with special heat exchangers, to reduce the effective energy requirement for the evaporation of water far below the level of enthalpy of vaporization. The realization of the low-temperature concept according to the invention with efficient energy recovery will be discussed later on the basis of a concrete preferred example. According to calculations, a theoretical thermal energy consumption of less than 800 kJ / kg water is possible. If loss sources such as non-ideal heat exchangers, radiation etc. are taken into account, according to the invention a value of below 1,500 kJ / kg water can be achieved. Without the heat recovery according to the invention, a dryer with identical operating parameters would require approximately 4,500 kJ / kg of water.
    According to a preferred embodiment, the inventive system for efficient energy recovery or energy utilization can be divided into at least two sections; in a pre-drying section A and a drying section B. Preferably, material is first predried in the pre-drying section and then transferred to the drying section, i. there is an " interface " between the pre-drying
    * * · · · · · Φ φ φ · I · **** ·· · · * * * * · »» »· · · * * * * * * * * * > * * φ · * »I« · - 6 -...... cut and the drying section for material transfer. In addition, it is preferable to transfer energy from the drying section B to the pre-drying section A, that is, there exists an " interface " between the drying section and the pre-drying section for energy transfer. The pre-drying section also differs from the drying section in at least one of the following features.
    Preferably, the drying air passing through the drying room of the drying section has a higher temperature than the pre-drying air passing through the pre-drying room of the pre-drying section. The temperature levels are dependent on the temperature of the supplied air in addition to the ambient temperature and ambient humidity.
    Preferably, the drying air is passed through the drying space at a lower flow rate (mVh) than the pre-drying air passed through the pre-drying room, i. the flow rate is preferably higher in the pre-drying room than in the drying room. Generally, a flow rate ratio of 1 / 2.5 to 1/7 is preferred.
    Preferably, the drying air in the drying section is guided in a closed circuit and / or the pre-drying air of the pre-drying section in an open " cycle " passed through the pre-drying room.
    Preferably, the material to be dried is conveyed with a transport device at least partially through a pre-drying space, which forms part of the pre-drying section. Even during pre-drying, the material can be turned several times within the pre-drying chamber. According to the above-described drying process, pre-drying air is preferably passed through the pre-drying space substantially opposite to the conveying direction of the material. The pre-dried by the pre-drying air material is then transferred to the drying room over.
    According to the invention, in the drying section, the heated air passed through the drying space is preferably heated and cooled in a drying air circuit, the drying space preferably forming part of the drying air circuit.
    In particular, due to differences in vapor pressure between the drying air and the water stored in the material, the bound water is driven from the material and absorbed by the air.
    According to the invention, the (liquid) storage capacity of the drying air within the drying space can be fully or partially utilized, i. the relative humidity of the discharged drying air (i.e., the drying air after passing through the drying room) is preferably between 75% -95%.
    Within this drying air circuit, the system according to the invention has at least one heat exchanger for heating / heating the air which is supplied to the drying space, and preferably at least one heat exchanger, preferably a condenser for cooling the air discharged from the drying space. The first heat exchanger for heating / heating the air is operated with energy supplied to the system from an external power source, for example in the form of heat energy from a heating plant or CHP plant. The energy recovered by the heat exchanger or condenser for cooling the air discharged from the drying space is returned to the system itself, i. preferably the drying section and / or the pre-drying section.
    In order to achieve a substantially trouble-free and preferably effective heat transfer or energy recovery by means of the last-mentioned heat exchanger / condenser, the air is filtered after passing through the drying room, preferably by means of a filter unit and / or a dust separator, i. the filter unit or Staubabscheidereinheät is preferably arranged upstream of the heat exchanger or condenser and downstream of the drying space. By means of this heat exchanger or condenser, the discharged air is further cooled and / or the water content in the air is reduced or removed, whereby energy is recovered which is returned to the system.
    A condenser or an energy and water sink is preferably used in addition to the cooling of the liquid removal (Wasserentfemung) from the drying air. In particular, the energy recovered by condensation is preferably used to pre-dry the material in the pre-drying unit. The energy recovered by the heat exchanger or condenser may alternatively or additionally be used to preheat the drying air within the drying air cycle, wherein the preheated drying air is then further heated / heated by means of an external energy source and supplied to the drying space.
    According to the invention, a considerable proportion of the energy contained in the drying exhaust air is operated at relatively low temperatures with the aid of an energy and water sink, in particular in the form of a condenser. In other words, in contrast to known vapor condensers, which are operated at very high temperatures (for example at the boiling point of the water), the capacitor according to the invention is preferably operated in a temperature range below 70 ° C, preferably below 60 ° C, for example below 50 ° C. Preferably, the operating temperature of the capacitor is adjusted depending on the temperature of the drying air and temperature of the ambient air. That It is relatively much energy, but at a relatively low Temperaturmveau obtained. This relatively low temperature, which is between about 30 and 70 ° C, depending on the preferred embodiment, can be used according to the invention, however (i) for a pre-drying process and / or (ii) for pre-heating the drying air.
    According to a preferred embodiment of the invention, the temperature of the air supplied into the drying space is higher than the temperature of the air fed into the pre-drying space. Thus, the temperature of the air supplied to the pre-drying space is preferably between 20-80 ° C, more preferably between 40-70 ° C. Preferably, the air supplied to the pre-drying room is heated ambient air returned to the environment after passing through the pre-drying room (ie open air circuit). The temperature of the air supplied into the drying room is preferably between 80-240 ° C preferably between 180-240 ° C and for wood chips particularly preferably between 110-1 50 ° C.
    The heating of the gas in step (i) is preferably carried out by means of a gas-liquid heat exchanger, wherein the liquid cooled after the gas heating serves for cooling and optionally for condensing the gas which is discharged from the drying space. Preferably, as the gas-liquid heat exchanger, an air-liquid, a gas-water or an air-water heat exchanger is used, wherein the temperature spread between gas inlet t-liquid outlet and gas outlet Flüssigkeitsseinritt is preferably low, for example at most 10 ° C. is, preferably about 3 ° C or less,
    According to the invention, air is used as the drying gas, with the aid of which preferably water is removed from the material. The relative humidity at the outlet of the drying space is preferably between 75% and 95% relative humidity. The temperature of the air at the outlet of the drying space is preferably between 20 ° C and 90 ° C.
    The advantages of the drying system according to the invention over known drying systems of the prior art are briefly summarized below. A prior art tumble dryer is usually very expensive to install and operate, whereas the drying system of the present invention having a spiral conveyor as a transport mechanism is inexpensive to install and operate. In particular, drum dryers require a high thermal energy consumption, whereas the energy recovery or energy recovery according to the invention represents a very efficient drying system.
    Convection dryers have a high energy consumption, similar to tumble dryers, i. the efficiency is significantly worse compared to the system of the present invention. In particular, the energy consumption of the present invention can be reduced, for example, by low number of revolutions of the spiral conveyor. In addition, a drying system with low pressure losses can be realized with the spiral beater according to the invention. Recirculating air dryers often also have the problem that the degree of moisture of the dried end product is relatively indefinite. By adapting the individual parameters for operating the system according to the invention, the degree of moisture of the dried material can be predicted relatively well.
    In other words, by means of the inventive efficient energy or heat recovery in the system according to the invention itself, for example by using low-temperature waste heat and / or by combination of established components and innovative measurement and control technology, the system or method according to the invention is in particular 9e also economically viable for low-energy substances such as biomass.
    Brief description of the drawings
    Hereinafter, preferred embodiments of the present invention will be described with reference to the figures:
    FIG. 1 shows an embodiment of a drying system according to the invention with a pre-drying and drying in the form of a block smear;
    Figure 2 shows another embodiment of a drying system according to the invention with a pre-drying and a drying and is additionally provided with exemplary values for temperature and relative humidity;
    FIG. 3 shows an h-x diagram (Mollier diagram) of the schematic drying process illustrated in FIG
    Detailed description of the drawings
    FIG. 1 shows an embodiment according to the invention of a drying system with energy recovery according to the invention. The illustrated embodiment may be divided into a pre-drying section Λ (top) and a drying section B (bottom). The two sections are over at least two " interfaces " coupled together, namely a "material interface" (AB-M) and an "energy interface" (AB-E). Preferably, the material is pre-dried in section A and transferred via the material interface to section B. On the other hand, energy, preferably recovered energy, is transferred from section B to section A.
    Drying Section B: Drying of the material is performed by means of a blower 9 circulated drying air 100 using an air heater 5, which is operated for example with heat from a combined heat and power plant, and fed to a drying room 1. The drying space 1 shown schematically in FIG. 1 can be embodied, for example, as a cylindrical drum, in the interior of which a transport device extends along the longitudinal direction of the drum. Preferably, a spiral conveyor as described above is used as the transport device. The material to be dried, i. the moisture-containing material or the wet biomass is supplied to the drying room 1 from the left side (entry), transported from left to right through the drying room 1 and discharged on the right side of the drying room 1 (material discharge 43). During the passage through the drying chamber 1, the warm or hot air dries the product, i. picks up some of the liquid present in the product, i. the drying air cools down. Accordingly, the absolute water content (x [kg water / kg air]) of the drying air increases; Consequently, the relative humidity of the drying air increases.
    The cooled and enriched with liquid air 101 is substantially freed by means of filter (unit) 2 on the left side of the drying chamber 1 (material entry) of airborne particles (dust). The Filtcreinheit 2, which is used in particular the dust separation from the Trock- nungsablufi, preferably characterized by a backwash and / or a low pressure loss and / or a good Staubrückhaitevermögen to occupy the downstream heat exchanger / condenser 3 with dust as well as possible to avoid.
    Lin part of the " residual energy " - i. the energy remaining in the drying air - the drying air 101 from the drying room 1 is recovered by means of the heat exchanger / condenser 3 and used to preheat the air in a closed circuit in the air preheater 4 and sucked ambient air 102 by means of the air heater. 7 in the pre-drying section A to heat. In other words, the recovered energy is transferred from the drying section B to the pre-drying section A and the drying section B.
    The transported by a blower 8 ambient air 102 is heated by means of the air heater 7 in the pre-drying section A and then on the right side (material discharge) zugelührl the pre-drying chamber 6; it flows through the pre-drying chamber 6 against the transport direction of the goods from right to left, and is discharged on the left side (material entry) as exhaust air 103 to the environment. Similar to the drying room 1, the material is transported for example by means of an axisless spiral against the air flow.
    The heat exchanger or condenser 3 in the drying section B is used in particular for the removal of water from the drying exhaust air 101 and the heat recovery. Preferably, a water-air heat exchanger is used, which is characterized by the lowest possible temperature difference between air inlet water outlet and Lullaustritt-water inlet. A large exchange surface can be achieved for example with a Lamel 1 en-Ripprohr heat exchanger. Usually, the temperature of the heated ambient air 102, which is supplied to the drying chamber 6, below the heated drying air 100, which is supplied to the drying room 1. Again, a filter 2, the discharged exhaust air 101 of suspended particles (dust) free.
    FIG. 2 shows an embodiment of a drying system according to the invention. The reference numerals of Fig. 2 correspond substantially to the reference numerals of Fig. 1, but to the reference numerals relating to the air, the number has been increased by 100. In addition, exemplary values for the gas or liquid temperatures are shown in FIG. 2, which are partially drawn in FIG. 3 in the hx diagram. Like the embodiment in Figure 1, the embodiment shown in Figure 2 can be subdivided into pre-drying (top, A) with pre-drying chamber 6 and drying with drying chamber 1 (bottom: B). Similar to the embodiment shown in FIG. 1, the drying section A and the pre-drying section are two substantially separate sections, but connected by at least one material transfer and energy transfer.
    The material to be dried 40 is supplied to the pre-drying chamber 6 on the left side, transported by means of transport means (for example by means of spiral conveyor 611) to the right /.um material discharge of pre-drying chamber 6; supplied from the pre-Trockenkammcr 6 via a lock 41 (for example, a rotary feeder) of the drying chamber 1 on the left side; again by means of a transport device (for example by means of spiral conveyor 111) to the right to the material discharge 43 of the drying chamber 1, from where the dried material can be processed further, for example, for thermochemical conversion to lean gas or synthesis gas or can be burned directly.
    With the help of the air heater 5, which derives its energy, for example, from a cogeneration plant or a cogeneration unit, the drying air is heated. As in the embodiment shown in FIG. 1, heated air is supplied to the drying space 1 on the material discharge side (air inlet) and, contrary to the material transport through the drying space 1, from right to left. The air to be heated is a circulating drying air.
    A concrete embodiment of the drying system according to the invention is described below in parallel with reference to FIG. 2 and the associated h-x diagram (see FIG. 3) with exemplary temperature values. For example, the drying air is heated by the air heater 5 from about 40 ° C (P2) to 200 ° C (P3). The corresponding change in state of the drying air heated in this way corresponds in the h-x diagram to a vertical line between the points P2 and P3, d. H. the state point shifts vertically when the air is heated (the absolute water content remains unchanged).
    This heated drying air flows through the drying chamber 1 here from right to left, whereas the material is transported from left to right. There is a direct heat transfer in countercurrent. The performed heated drying air sweeps over the property, while the liquid evaporates. In other words, the heated drying air partially extracts the liquid from the material, whereby the absolute liquid content of the air carried increases (x increases) and the temperature of the drying air carried out also decreases. At the material inlet or gas outlet on the left side of the drying chamber 1 here, the cooled and liquid-enriched drying air is discharged to a filter unit 2.
    The change in state within the drying chamber 1 corresponds to the example of the distance from P3 to P4 in the h-x diagram of Figure 3. The temperature decreases from about 200 ° C to about 46 ° C; the absolute water content and the relative humidity (about 90%) increase, whereas the enthalpy of the air decreases slightly ** * ·· ·· »» ··· · ···· ** · ··· * * · · ······································································ (12)
    The filter unit 2 is essentially used for the removal of dust from the drying air and is preferably characterized by a good backwash, a low pressure drop and a preferably good dust retention to avoid occupancy of the subsequent heat exchanger / condenser 3 with dust as well as possible.
    The filtered exhaust air is supplied to the condenser 3, whereby the exhaust air is first cooled (i.e., the absolute water content is substantially unchanged and the state in Figure 3 shifts vertically downward to the taulinic, relative air humidity 100%). Then, water is removed from the drying air exhaust by the condenser 3 (state change along the dew line to the left, see route P4 to PI). The condensation recovers a considerable amount of energy. After passing through the condenser 3, the drying air has a relative humidity of about 100% and a temperature of about 20 ° C (PI).
    This energy obtained by condensation is partially (about 10-30%) used in the concrete example to about 14% to reheat the drying air with the heater 4, ie. a portion of the energy obtained remains in the drying section B. Thus, for example, with the aid of the condenser 3 water is heated to about 42 ° C, wherein a portion of the heated water is supplied to the heater 4, the air from about 20 ° C to ca Heated to 40 ° C, ie the air is warmed up without the absolute water content changing. Accordingly, the state change in FIG. 3 can be represented by the distance PI to P2. The heated to 40 ° C air is then heated again with the aid of the air heater 5 to 200 ° C; the drying air circuit is closed.
    A large part (about 70-90%) of the energy gained by the condenser 3 is supplied to the pre-drying A. In the concrete example of FIGS. 2 and 3, the water which has been heated in the condenser to about 42.degree. to a pre-drying room 6, in the concrete example the ambient air temperature is 10 ° C with a relative humidity of 50% (see (P5) in FIGS. 2 and 3). The ambient air is heated by means of the heater 7 to about 40 ° C (vertical state change in Fig. 3 of P5 to P6), said pre-drying air through the pre-drying chamber 6 here from right to left, i. against the transport direction of the goods, passed. During pre-drying within pre-drying room 6, the drying air is again moistened, i. the material is dried, which corresponds to a change of state in the direction of the dew-line (see route P6 to P7 in FIG. 3). In this case, it is desirable to utilize the maximum load capacity of the air, that is, the air is preferably cooled down to the dew line, which would correspond to a relative humidity of 100%. In the specific example, the relative humidity is about 99% while the temperature is 16.5 ° C (P7). Since hardly any energy can be recovered from this cold and moist air, the air is preferably released into the environment, ie, unlike in the * ···················································································································································································································.
    The water temperature, which was supplied to the heater 7 in section A at about 42 ° C from section B, after heating the ambient air is only about 13 ° C. This cooled water is passed from the pre-drying section A back to the drying section B and heated there again by means of the capacitor 3 to about 42 ° C. In addition, the waste water of the heater 4, which has a temperature of about 22 ° C, was heated by means of the capacitor 3. As the waste water of the heater 7 (about 13 ° C) is mixed with the waste water of the heater 4 (about 22 ° C) before heating in the condenser 3, the water temperature of Kondcnsatorzulcitung example, about 16 ° C.
    With regard to the h-x diagram of FIG. 3, it should be noted that the drying air flows in the pre-drying space 6 and in the drying space 1 preferably differ from one another. So it is preferred that the volume flow in pre-drying space is greater than in the drying room.
    权利要求:
    Claims (15)
    [1]
    1. A process for drying a moisture-moist material, in particular of bulk materials and biomass, comprising the steps of: conveying the material with a transport device at least partially through a drying space (1), wherein the material is preferably turned several times, passing a heated gas, preferably air, through the drying space substantially along or against the transport direction of the transport device, wherein the residual energy contained in the gas after passing through the drying space (1) by means of at least one heat exchanger means (3) is returned, so that the energy required for drying the material below the necessary enthalpy of enthalpy of water, and preferably below 2200 kJ / kg, more preferably below 1500 kJ / kg, and preferably below 1000kJ / kg.
    [2]
    2. The method of claim 1, wherein the heated and through the drying chamber (1) performed gas in a drying gas circulation is heated and cooled, wherein the drying space (1) preferably forms a part of the Trocknungsgaskrcislaufes.
    [3]
    3. The method of claim 1 or 2, wherein the gas passed is filtered after passing through the drying chamber (1) by means of a filter unit (2) and / or a dust separator, in a condenser (3) is further cooled and then through the The energy recovered from the condenser (3) is heated, and then further heated to drying temperatures and again through the drying room (1) is performed.
    [4]
    4. The method of claim 3, wherein liquid is removed from the cooled gas in the form of liquid or condensed by the condenser (3) and the condensation energy is used to reheat the gas in the drying gas cycle (4) and / or the gas for Preheat a pre-drying (6). * · · · · · «* · · · ·························································································· tt · · · - 15 -
    [5]
    5. The method according to any one of claims 1 to 4, wherein prior to the drying described in claims 1 to 4, a pre-drying of the material is carried out, wherein the material with an upstream transport device (6) at least partially by a pre-drying space (6 ), wherein the material is preferably turned over several times, a pre-drying gas is passed through the pre-drying space (6) substantially along or against the transport direction of the upstream transport device (6), the material pre-dried by the pre-drying gas is activated the drying room (1) is transferred.
    [6]
    6. The method according to any one of claims 1 to 5, wherein the drying chamber (1) and / or the pre-drying chamber (6) has a cross-sectionally at least partially (circular) arc-shaped drum, within which the transport device, preferably in the form of an inside the and relative to the drum rotatable Spiralforderwendel, angeordnel is.
    [7]
    7. The method according to claim 6, wherein the material during transport, preferably by the spiral lorder spiral (1,6) by means of additional attached to the spiral conveyor turning devices, is turned.
    [8]
    8. The method of claim 5, 6 or 7, wherein the temperature of the in the drying chamber (1) supplied gas is higher than the temperature of the pre-drying chamber (6) supplied gas.
    [9]
    9. The method of claim 5, 6, 7 or 8, wrobei the temperature of the pre-drying chamber (6) supplied gas, preferably air, between 20-70 ° C, preferably between 40-50 ° C, with a water load from 0-55g / kg dry air
    [10]
    10. The method according to any one of the preceding claims, wherein the gas emitted from the drying chamber (1) by means of heat exchanger (3) is cooled and optionally contained therein liquid or water is condensed and the heat emitted (i) is used to heat the gas, the Vor Drying space (6) is supplied and / or (ii) for heating the gas, which is the drying room (1) is supplied. 16
    [11]
    11. The method according to any one of claims 5 to 10, wherein in the pre-drying chamber (6) supplied gas is heated ambient air, which is returned to the environment after passing through the pre-drying chamber (6).
    [12]
    12. The method according to claim 10 or 11, wherein the heating of the air in step (i) by means of air-water heat exchanger (7) is performed, wherein the abge after the air heating cooled water for cooling the air discharged from the drying room (1) is used and optionally used to condense the liquid bound in the discharged air.
    [13]
    13. The method according to any one of the preceding claims, wherein the temperature of the in the drying room (1) supplied gas is between 80-350 ° C, preferably between 100-200 ° C.
    [14]
    14. The method according to any one of the preceding claims, wherein the relative humidity at the outlet of the drying chamber (1) between 75% and 95% relative humidity and the temperature is preferably between 20 ° C and 90 ° C.
    [15]
    15. A system for drying biomass, such as woodchips, comprising: a pre-drying section (A) for pre-drying the biomass and a downstream drying section (B) for drying the pre-dried biomass, the drying section (B) having a drying room (1) through which the biomass is transported by means of a transport device, and a heated gas, preferably air, is carried out substantially opposite to the transport direction of the biomass, leaving the drying space (1) as exhaust gas, wherein a heat exchange device (3) in the drying section (B ) is arranged downstream of the drying chamber (1), with which is obtained from the exhaust energy, which is transferred to the pre-drying section (A), so that the energy required to dry the material below the necessary enthalpy of enthalpy of water, and preferably below 2,200 kJ / kg, more preferably below 1500 kJ / kg and preferably below vo n 1.000kJ / kg.
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    同族专利:
    公开号 | 公开日
    WO2012045552A1|2012-04-12|
    AT510487B1|2012-09-15|
    EP2625481A1|2013-08-14|
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    WO1990001664A1|1987-02-03|1990-02-22|Drytec Ab|A method of drying wood|
    CH677527A5|1989-02-15|1991-05-31|Hydrotechnik Gmbh|Wood drying plant for chipboard mfr. - uses mechanical compression for removing moisture before final drying|
    DE9311698U1|1993-08-05|1994-06-23|Limex Gmbh Ges Fuer Angewandte|Device for the dehydration and drying of solid-liquid mixtures |
    EP2115368A1|2007-02-02|2009-11-11|Steve D. Shivvers|High efficiency drier with multi stage heating and drying zones|
    DE102009014020A1|2009-03-23|2010-09-30|Bühler AG|Method and device for drying goods|SE537903C2|2013-04-08|2015-11-17|Valutec Ab|Procedure for drying wood with warm air and a duct dryer|
    AT515466B1|2014-02-26|2016-05-15|Mühlböck Kurt|Process for drying bulk material|
    DK3230671T3|2014-12-08|2020-03-02|Stela Laxhuber Gmbh|DRY SYSTEMS WITH A DRY AREA|
    DE102015108742B4|2015-06-02|2019-04-25|Ecolohe Ag|Process and apparatus for processing organic solid fuels, in particular woodchips|
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    法律状态:
    2017-06-15| MM01| Lapse because of not paying annual fees|Effective date: 20161007 |
    优先权:
    申请号 | 申请日 | 专利标题
    ATA1673/2010A|AT510487B1|2010-10-07|2010-10-07|DRYING PROCESS AND DRYING SYSTEM|ATA1673/2010A| AT510487B1|2010-10-07|2010-10-07|DRYING PROCESS AND DRYING SYSTEM|
    EP11757281.8A| EP2625481A1|2010-10-07|2011-09-13|Drying method and drying system|
    PCT/EP2011/065801| WO2012045552A1|2010-10-07|2011-09-13|Drying method and drying system|
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