WO2014147089A1

WO2014147089A1 - Method and system for processing biomass, preferably a system for producing paper, pellets, or material panels

Info

Publication number: WO2014147089A1
Application number: PCT/EP2014/055440
Authority: WO
Inventors: Wolfgang ALLERÖDDER; Jochim BÄCKER
Original assignee: Dieffenbacher GmbH Maschinen- und Anlagenbau
Priority date: 2013-03-19
Filing date: 2014-03-18
Publication date: 2014-09-25
Also published as: DE102013102795A1

Abstract

The invention relates to a system and a method for processing biomass in a system, comprising the following steps: drying the biomass (B) in a drier (13) in order to produce dried biomass (BT), discharging the exhaust air (A) of the drier (13) in a flue (15) to the environment, and processing the dried biomass (BT) in a part of the system, preferably in a processing system (14) for producing paper, pellets, or material panels. The problem addressed by the invention is reducing the necessary use of fresh water and/or increasing the efficiency of the whole system by reusing the low-calorific energy. The problem is solved in that at least a partial flow of the exhaust air (A) containing moisture is sprayed with water (W) in a spraying tower (2) between the drier (13) and the flue (15) and said moisture is condensed into condensate (K) in the spraying tower (2) by the accompanying cooling of the exhaust air (A) and in that the waste water (AW) arising from the condensate (K) is used to moisten and/or control the temperature of the biomass (B) in parts of the system.

Description

Method and plant for processing biomass, preferably a plant for the production of paper, pellets or material plates

The present invention relates to a method for processing biomass, preferably a plant for the production of paper, pellets or material plates, according to the preamble of claim 1 and a plant for processing biomass according to the preamble of claim 10.

From the state of the art are equipment and the essential physical

Operations in these facilities already known.

DE 35 34 260 A1 discloses a method for thermal drying

temperature-sensitive goods in rotary drums, in particular of biomass. It is described that for drying usually high-temperature flue gases are used directly or indirectly to dry the goods. In particular, the recirculation of the vapors (exhaust air) of the dryer for reuse as mixed air for controlling the flue gases is proposed in order to avoid heat losses. However, the majority of the wet vapors are still released to the environment, as usually not so much vapor can be used as mixed air in connection with the combustion, to ensure a complete cycle. The vapors are already loaded with moisture and from too high

Moisture would be the mixed flue gases in a direct drying no longer suitable to absorb moisture from the material.

From DE 42 17 1 16 A1, a general method for purifying air has become known, enriched with the exhaust air or exhaust gas with water vapor and then cooled below the current dew point for the liquid in question. It forms a mist, which absorbs the air polluting substances and can be separated.

Essentially, these physical processes also use a wet electrostatic precipitator, in which the exhaust air of a dryer is sprayed with water and thus saturated. The saturated exhaust air is finally ionized and dust and aerosols are deposited on the electrodes, which in turn are cleaned by means of water spraying. This wastewater is regenerated and usually in turn for water spraying However, a large part of the water escapes through the saturation of the water in the exhaust air through a fireplace. In principle, wet electrostatic precipitators are operated in such a way that the amount of wastewater discharged remains as low as possible.

Basically, it is therefore known to expose exhaust gases in industrial application of a targeted saturation in a spray tower, the skilled person knows it but usually deliberately to avoid unnecessarily produce wastewater that will be regenerated and purified. For this purpose, the exhaust air is usually saturated only in such a way that when cooling, although a certain condensation effect occurs, but this should be kept as low as possible, cf. For this purpose, the above-described application of

Wet electrostatic precipitators.

Such systems, however, always have a generous use of fresh water in the individual parts of the system and of course in the spray tower, since the moisture is absorbed by the exhaust air and can be discharged in gaseous form via a chimney. In the interests of environmental protection, it is only necessary to clean the exhaust air in such a way that it contains no or only a small amount of pollutants.

The moisture content of the exhaust air is usually taken into account only if misting and rain in the immediate vicinity is to be avoided, especially in cold seasons.

From DE 601 02 915 T2 a method and an apparatus for thawing tree trunks by means of hot water or steam has become known. Such methods or equipment may be used in the present process under circumstances where the biomass should be in the form of tree trunks. For this purpose, it is necessary hot water or steam by means of an expensive

Primary energy (gas, oil, coal, wood ...) to produce and irrigate the tree trunks with the heated medium or apply. Again, it is necessary to use a lot of fresh water, which must be processed to hot water or steam. Thus, in conventional processes and plants, generalized biomass is processed by drying the biomass in a dryer to dry

Biomass, the discharge of the exhaust air of the dryer in a chimney to the environment and the processing of the dried biomass in a part of the plant, preferably in a processing plant for the production of paper, pellets or material boards happens.

The present invention therefore has the technical object to provide a system and a method in which the use of fresh water over the prior art can be saved and / or in which the efficiency of the entire system can be increased by reuse of low calorific energy.

The solution for the method comprises that at least a partial stream of the moisture-containing exhaust air between the dryer and the fireplace sprayed in a spray tower with water and the concomitant cooling of the exhaust air, this moisture is condensed in the spray tower to form condensate and

that the effluent from the condensate for humidification and / or

Temperature control of the biomass is used in parts of the plant.

Essentially, the exhaust air is supersaturated with moisture by the humidity of the exhaust air is enriched until the exhaust air can no longer absorb moisture. Due to the parallel cooling, the moisture and the heat contained in the air are removed via the condensate of the exhaust air and stored in the resulting wastewater. The exhaust air cools accordingly, the condensing moisture and also the exhaust air flowing through the water takes on a higher temperature.

This creates a high-temperature wastewater, which can be used directly for heating or for thawing the biomass, depending on

Use case may lead to indirect or direct heating. In a direct heating, the wastewater is directly back to the biomass (eg.

Tree trunks) brought into contact. When contacting takes place but usually not only a warming, but water is also absorbed by the biomass in this case, then dried out of the biomass in the dryer and transferred to the exhaust air, there again condensed out of the exhaust air in the spray tower and thus be reused. This results in a nearly closed cycle Water. In any case, it is thus achieved that the fresh water consumption of comparable processes or plants is significantly reduced and quasi-low-calorie energy can be usefully used in a meaningful way.

The solution for the system is that in the system between the dryer and the fireplace, a spray tower for spraying at least one moisture-containing partial flow of the exhaust air is arranged with water, which is suitable to collect the condensate resulting from the associated cooling of the exhaust and wherein means are provided in the system to supply the effluent from the condensate at least parts of the system for humidification and / or temperature control of the biomass.

The advantages of the invention therefore essentially comprise individual and especially in

Combination:

- the saving of fresh water;

- the at least partial reuse of water in a cycle;

the use of low calorific energy of the exhaust gases to increase the

Energy efficiency of the whole plant;

- The simple and energetically more cost-effective air purification of the exhaust gases compared to a regenerative thermal oxidation (RTO) or a wet electrostatic precipitator, or if this is still necessary at least a first preliminary or partial cleaning of

Exhaust gases.

Particularly noteworthy is now the fact that compared to the previous practice of heating fresh water for thawing or tempering the biomass and use, now accumulating wastewater can be meaningfully used.

In particular, the fact is taken into account that so far fresh water has been used in spraying the biomass, taken in the course of the temperature control by the biomass, then in the dryer dryer exhaust air and

was subsequently discharged to the environment. This water is now in the

Essentially circulated and reused, which significantly reduces the fresh water requirement of the entire plant. By using the low calorie energy, there is even an energetic advantage that further significantly improves the overall economy of the plant. Advantageously, the inventive method and the device also has advantages in a possible connection of a wet electrostatic precipitator, since this almost no fresh water supply needed, since the exhaust air is saturated here already on the necessary content and it can be transferred directly to the ionization to more

Remove pollutants from the exhaust air.

In essence, it is therefore conceivable that the temperature or the humidification by means of the resulting wastewater in all parts of the system could find direct or indirect, complete or supportive, use.

It would be conceivable to use the wastewater for the production of steam for the

Steaming the shredded wood before pelleting or pressing. Also, an admixture of the waste water in the glue liquor, with a possible corresponding heating of the glue liquor is conceivable.

Necessary cleaning measures of the waste water will be considered by the skilled person with appropriate use, if advised. For example, the water can be sprayed substantially unrefined directly on tree trunks for heating, whereas the use of the wastewater, for example, in a glue liquor or as a vaporization a corresponding pre-cleaning or pH adjustment may be necessary.

In a preferred embodiment, therefore, the waste water for humidification and / or temperature control of the biomass in the dryer upstream

System parts are used.

To save or reuse drying energy can

Temperature level of the biomass before drying in the dryer by means of

Sewage are increased directly or indirectly. Preferably, the biomass can thus be thawed before comminution and / or before drying. This would be

For example, especially in winter necessary or useful for facilities that are provided in cold areas with regular frost.

The biomass can preferably be comminuted before and / or after drying in the dryer in a device, preferably in a hacker and / or in a mill, and, if necessary, moistened beforehand and / or after and / or tempered. This may be particularly useful when using biomass

Logs or from a recycling.

In one possible embodiment, the exhaust air between the dryer and the spray tower and / or between the spray tower and the chimney in a

Cleaning device to be cleaned, preferably by means of a wet electrostatic precipitator and / or a regenerative thermal afterburning.

In one possible embodiment, for discharging the exhaust air from the chimney, a partial flow of hot exhaust air can be branched off before the spray tower or fed from another source and mixed after the spray tower with the cooler exhaust air from the spray tower. Such is the temperature of the exhaust air and thus the absorption capacity of the exhaust air is increased again, which reduces the relative humidity within the exhaust air and helps prevent the formation of steam outside the fireplace with appropriate cooling to the ambient air.

In particular, it can also be provided for the wastewater to heat at least parts of the plant or indirectly for feeding into a district heating system

use.

Plant technology, it may be provided for the further development of the system according to the invention, that for direct use of the waste water atomizer or

Steam generators and / or for indirect use heat exchangers are arranged.

In particular, it can be provided that the spray tower for the use of the waste water for humidification and / or temperature control of the biomass with the dryer upstream equipment parts is operatively connected by means of lines. Lines are in the context of the invention suitable pipelines with corresponding drive means (pumps), which are suitable, the necessary fluids (water, sewage,

Fresh water, condensate and the like) to their destination. Lines can also be arranged for air guidance, such as, inter alia, for the flue gases or exhaust air. In particular, it can be provided that the plant continues to shred the biomass before and / or after drying in the dryer a

Crushing device, preferably a hacker and / or a mill comprises.

In a further additional embodiment may be arranged in the system for cleaning the exhaust air between the dryer and the spray tower and / or between the spray tower and the chimney, a cleaning device, preferably a

Wet electrostatic precipitator and / or a regenerative thermal afterburning.

In a further additional embodiment, for the discharge of the exhaust air from the chimney lines for the separation of a partial flow of hot exhaust air before

Be arranged spray tower, which are operatively connected to the lines of cooler exhaust air from the spray tower to the mixture.

In a further preferred embodiment, means for using the waste water for heating at least parts of the plant or for indirect feed can be arranged in a district heating system.

The process and the plant can be operated independently of each other; but the system may also be suitable in particular for carrying out the method.

Further advantageous measures and embodiments of the subject matter of the invention will become apparent from the dependent claims and the following description with the drawing. The illustrated in the figure description

Combination options are all alone and independently and in any combination usable. In particular, individual sentences should also be evaluated as independent characteristics, similar to new paragraphs.

Show it:

Figure 1 is a schematic representation of a plant according to the prior art, Figure 2 is a simplified schematic representation of an inventive

Plant and

FIG. 3 shows a more extensive illustration according to FIG. 2. Figure 1 shows a schematic representation of a plant 1 according to the prior art for processing biomass to an unspecified

Final product. This end product may preferably be paper, pellets, in particular for combustion in hearths or even a material plate. In the present example, a plant 1 for the production of material plates is shown, in which a storage space 17 for storage of logs 7 (as biomass B) and in

Production direction below a tempering 4 is arranged. In the tempering device 4, preferably by means of a water bath and / or a sprinkler 9, the tree trunks 7 tempered, so preferably warmed up or even thawed. For this purpose, an energy system 1 1 is normally provided which supplies the water bath and / or a water cycle for the sprinkler 9 with heat energy via a thermal oil supply 20 and a suitable heat exchanger 10. The water cycle has an inlet for fresh water FW, which substitutes the water leaving the circuit, which either evaporates or is taken up by the logs 7. The logs 7 are then in a crushing device, registered here as a hacker 16, crushed and as wood chips 8 on a

Input lock 12 is fed to the dryer 13 for drying. The

Input lock 12, respectively the dryer 13, is supplied directly by means of a burner (not shown) or indirectly via the energy system 1 1 with flue gas RG a high temperature in order to dry the chips 8. In a dryer 13 downstream output lock 18, the chips 8 are separated from the flue gases RG, the chips 8 as dry biomass BT in a processing plant 14, usually via a Thermalolversorgung 19 with the power plant 1 1 operatively connected, further processed. The exhaust air A from the dryer 13, which has the moisture from the drying process from the dryer 13 is fed to a chimney 15 for transfer to the ambient air, wherein in front of the fireplace 15 is still a cleaning device 21, for example a

Wet electrostatic filter or the like can be arranged.

Hereinafter, preferred embodiments of the present invention will be explained in detail with reference to FIGS. 2 and 3. In a simplified representation according to FIG. 2, the treatment of the biomass is represented by two possible types (also combinatorially applicable as in FIG. 1) of tempering devices 4, after which the biomass B enters the dryer 13 and further processes it as dry biomass BT in a processing plant 14 becomes. According to the invention, at least part of the exhaust air A is introduced from the drier 13 into a spray tower 2, in which the ascending exhaust air A is supplied with water W by means of an atomizer 3. The cooling of the exhaust air A and the direct condensation produces condensate K, which can be discharged as effluent AW from the spray tower 2. It is now provided to use this wastewater AW indirectly via a heat exchanger 10 for heating the temperature control device 4, which is shown here by way of example as a water bath bottom left. Alternatively or in combination, the wastewater AW can also be directly in a

Temperierungsvorrichtung 4 are applied to the biomass B by means of a sprinkler 9. The recaptured water W is cooled again supplied to the atomizer 3 of the spray tower 2. Again, the direct use of water W would be possible in a water bath.

In a more detailed representation, essentially consisting of the representation of Figure 2, the missing details of Figure 1 are exemplarily added in a plant 1 according to the invention, so that now results in a storage 17, from the tempered logs 7 in a tempering 4 are introduced and tempered there in a water bath and / or by means of a sprinkler 9, preferably thawed. The water required for this purpose is conveyed as wastewater AW from the spray tower 2. The returned water W is then used again in the spray tower 2 by means of an atomizer 3 against the exhaust air A to cool the exhaust air A and the moisture from the exhaust air A.

condense (direct condensation). The exhaust air A is after the spray tower 2, preferably in a cleaning device 21, for example a

Wet electrostatic precipitator or RTO, final cleaned and then discharged through the fireplace 15 to the environment. To avoid the very humid air

(supersaturated from the direct condensation) in the lines from the spray tower or in the ambient air excessively condensed, it would be possible to divert a portion of the exhaust air A before the spray tower 2 and reunite after the spray tower 2 again with the remaining exhaust air A. Due to the resulting significant increase in temperature the relative humidity in the exhaust air A before the cleaning device 21 or the chimney 15 drops significantly.

In an alternative, but especially in a preferred additive

Embodiment, the resulting from the condensate K wastewater AW can be used to support other consumers or the heating system parts or halls of the system and this is via a heat exchanger 10 for receiving the low calorific energies by suitable consumers, here the processing plant 14 or another Tempering device 4 'passed in front of the dryer 13.

List of Reference Numerals: P1448

1 Annex B Biomass

2 spray tower BT dry biomass

3 atomizers

4 tempering device RG flue gases

5 A exhaust air

6

7 log FW fresh water

8 wood chips W water

9 Irrigation device K Condensate

10 heat exchanger AW wastewater

1 1 energy system

12 entrance lock

13 dryers

14 processing plant

15 fireplace

16 hackers

17 storage place

18 exit lock

19 thermal oil supply for 14

20 thermal oil supply for 10

21 cleaning device

Claims

claims

1. Method for processing biomass in a plant,

comprising drying the biomass (B) in a dryer (13) to dried biomass (BT),

the discharge of the exhaust air (A) of the dryer (13) in a chimney (15) to the environment and

the processing of the dried biomass (BT) in a part of the plant, preferably in a processing plant (14) for the production of paper, pellets or material plates,

characterized in that at least a partial stream of moisture-containing exhaust air (A) between the dryer (13) and the chimney (15) in a spray tower (2) with water (W) sprayed and by the associated cooling of the exhaust air (A) this moisture in the spray tower (2) is condensed to condensate (K) and

the effluent (AW) produced from the condensate (K) is used for moistening and / or tempering the biomass (B) in parts of the plant.

2. The method of claim 1, dad urch geken nzeichnet that the wastewater (AW) directly and / or indirectly for humidification and / or temperature control of the biomass (B) is used.

3. The method according to claim 1 or 2, characterized in that the waste water (AW) for humidification and / or temperature control of the biomass (B) in the dryer (13) upstream equipment parts is used.

4. The method according to one or more of the preceding claims, characterized in that the temperature level of the biomass (B) before drying in the dryer (13) is increased, preferably that the biomass (B) is thawed before drying.

5. The method according to one or more of the preceding claims, characterized in that the biomass (B) before and / or after the Drying in the dryer (13) in a device, preferably in a hacker (16) and / or in a mill, is comminuted.

6. The method according to one or more of the preceding claims, characterized in that are used as biomass (B) logs (7) and / or biomass from a recycling.

7. The method according to one or more of the preceding claims, characterized in that the exhaust air (A) between the dryer (13) and the spray tower (2) and / or between the spray tower (2) and the chimney (15) in a cleaning device (21), preferably by means of a

Wet electrostatic precipitator and / or a regenerative thermal afterburning.

8. The method according to one or more of the preceding claims, characterized in that for depletion of the exhaust air (A) from the chimney (15) a partial flow of hot exhaust air (A) branched off before the spray tower (2) and after the spray tower (2). with the cooler exhaust air (A) from the spray tower (2) is mixed.

9. The method according to one or more of the preceding claims, characterized in that the wastewater (AW) also for heating at least parts of the system or indirectly for feeding into a

District heating system is used.

10. Plant for processing biomass, comprising a dryer (13) for drying the biomass (B) to dried biomass (BT),

a chimney (15) for discharging the exhaust air (A) of the dryer (13) to the

Environment and at least part of the plant for processing the dried biomass (BT), preferably a processing plant (14) for producing paper, pellets or material boards,

characterized in that in the plant

between the dryer (13) and the chimney (15) a spray tower (2) for

Spraying at least one moisture-containing partial stream of the exhaust air (A) with water (W) is arranged, which is suitable by the Accompanying cooling of the exhaust air (A) condensate (K) to accumulate and means are provided in the system, the

from the condensate (K) resulting wastewater (AW) at least parts of the system for humidification and / or temperature of the biomass (B) supply.

11. Plant according to claim 10, characterized in that the

direct use of wastewater (AW) atomizers (3) or steam generators and / or for indirect use heat exchangers (10) are arranged.

12. Plant according to claim 10 or 11, characterized dad urch gekennzeich net, that the spray tower (2) for using the wastewater (AW) for humidification and / or tempering of the biomass (B) with the dryer (13).

upstream system parts is operatively connected by means of cables.

13. Plant according to one or more of the preceding claims, characterized in that the plant continues to

Comminution of the biomass (B) before and / or after drying in the dryer (13) comprises at least one comminution device, preferably a chipper (16) and / or a mill.

14. Plant according to one or more of the preceding system claims, characterized in that for cleaning the exhaust air (A) between the dryer (13) and the spray tower (2) and / or between the

Spray tower (2) and the chimney (15), a cleaning device (21) is arranged, preferably a wet electrostatic precipitator and / or a regenerative thermal afterburning.

15. Plant according to one or more of the preceding claims, characterized in that for the discharge of the exhaust air (A) from the chimney (15) lines for separating a partial flow of hot exhaust air (A) in front of the spray tower (2) are arranged, with the Lines of cooler exhaust air (A) from the spray tower (2) are operatively connected to the mixture.

16. Plant according to one or more of the preceding system claims, characterized in that means for using the wastewater (AW) for heating at least parts of the plant or for indirect feed are arranged in a district heating system.