JP2014034665A - Drying and carbonization system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new drying and carbonization system (multi-heating system) that achieves both drying and carbonization while saving energy.SOLUTION: A drying and carbonization system 1 comprises a dryer 2 to preliminarily dry a material W to be processed, a carbonization apparatus 3 to carbonize the preliminarily dried material W to be processed, a heat recovery apparatus 4 to recover heat from a carbonization exhaust gas CG discharged from the carbonization apparatus 3 so as to reuse the recovered heat as a heat source for the dryer 2, and an incinerator 5 that can incinerate part of the preliminarily dried material W to be processed. The heat recovery apparatus 4 is supplied with both the carbonization exhaust gas CG from the carbonization apparatus 3 and an incineration exhaust gas BG from the incinerator 5. Part of the incineration exhaust gas BG discharged from the incinerator 5 is sent to a carbonization furnace 31 of the carbonization apparatus 3.

Description

  The present invention relates to a system for carbonizing carbon dioxide, for example, sewage sludge and human waste sludge to produce fuel, fertilizer, and the like, and in particular, combining a carbonization device with a dryer and carbonizing an object to be pre-dried with a dryer. Carbonization is efficiently performed by supplying to the equipment, and a part of the object to be treated is incinerated in the incinerator, and the incineration exhaust gas discharged from the incinerator is used as the heat source of the carbonization equipment or as the carbonization exhaust gas. The present invention relates to a dry carbonization system in which energy is saved (so-called energy saving) by joining and reusing as a heat source of a dryer.

For example, a dry carbonization system in which a dryer and a carbonizer are combined is known as a technique for efficiently producing fuel and fertilizer by carbonizing and carbonizing sewage sludge (see, for example, Patent Document 1 by the present applicant).
For example, as shown in FIG. 5, the dry carbonization system 1 'preliminarily drys the workpiece W (material) to a certain water content with a dryer 2'. By introducing W into the carbonization apparatus 3 ', carbonization can be efficiently performed. Further, the carbonized exhaust gas CG discharged from the carbonization apparatus 3 'is heat-recovered and reused as a heat source for the dryer 2' to save energy. Furthermore, the dry exhaust gas DG discharged from the dryer 2 'can be completely burned by introducing it into the carbonization device 3' so that the dry exhaust gas DG containing odor can be completely burned without providing a deodorizing furnace. It has the advantage of.

In particular, in Patent Document 1, a screw type is applied as the carbonization apparatus 3 '. This is a carbonization furnace 31' provided with a dry distillation pipe 34 'containing a screw conveyor 35'. The carbonization treatment of carbonization is to carbonize the workpiece W while transferring the workpiece W in the heated dry distillation pipe 34 '(indirect heating).
In such a dry carbonization system 1 '(screw type carbonization apparatus 3'), the residence time of the workpiece W in the dry distillation pipe 34 '(passing time in the carbonization furnace 31'), the carbonization temperature, and the like are various. Since it can be adjusted, even one unit (one unit) has an excellent effect of being able to cope with various uses of carbides to be processed. Incidentally, since the dry carbonization system of patent document 1 can respond to the carbide | carbonized_material of various uses, the present applicant has called the said system as a multi-heating system.

The dryer 2 'includes a rotating heat transfer section 22' that rotates in the main body shell 21 '. In the rotating heat transfer section 22', a plurality of heating tubes 25 'through which steam passes are arc-shaped. In the pre-drying process of the workpiece W, the heating pipe 25 ′ is rotated while rotating the rotary heat transfer section 22 ′ in a state where steam flows in the heating pipe 25 ′. The workpiece W is indirectly heated through (conduction heat transfer type).
In addition, when recovering heat from the carbonized exhaust gas CG discharged from the carbonization apparatus 3 ', a waste heat boiler 41' that generates steam by heat exchange with the carbonized exhaust gas CG is provided. In order to make up for the shortage of heat, a once-through boiler 42 'is provided.

However, this dry carbonization system 1 'still has room for improvement in the following points.
That is, the conventional dry carbonization system 1 ′ has an excellent advantage that it can be used for various carbide applications. On the other hand, if the use is changed, the amount of dry distillation gas generated during the carbonization treatment is changed, and the amount of exhaust gas heat is different. However, the amount of fuel recovered when the steam is recovered by exchanging heat increases and decreases, and the amount of fuel used in the once-through boiler 42 ′ increases and decreases accordingly. In addition, since the amount of fuel used increases especially in the case of fertilizer application, fuel consumption is worsened and, as a result, the price of fertilizer as a product is increased.

More specifically, for example, when the purpose of carbonization is to change the dry product W as close to carbon as possible, or to reduce the volume of the dry product W and treat it as waste. Since the temperature of the carbonization apparatus 3 ′ (carbonization furnace 31 ′) is set to a high temperature exceeding 600 ° C. as an example, the amount of heat that can be recovered by the waste heat boiler 41 ′ is relatively large, but the purpose of carbonization is fuel and fertilizer. In some cases (when the dry product W is produced as a carbide for fuel use or a carbide for fertilizer use in the carbonization apparatus 3 '), a sufficient amount of organic or inorganic components remain in the workpiece W. For this reason, since the temperature of the carbonization apparatus 3 ′ (carbonization furnace 31 ′) is set to a medium to low temperature of about 400 ° C. to 600 ° C. as an example, the amount of heat that can be recovered is relatively small. Thus, if the purpose of carbonization is different, there is room for improvement in that the amount of heat that can be recovered from the exhaust gas also varies. Here, as described above, carbonization at a temperature exceeding 600 ° C. is referred to as “high temperature carbonization” for convenience, while carbonization at 600 ° C. or lower is referred to as “low temperature carbonization” for convenience.
Further, in the reburning furnace 32 'in the carbonization apparatus 3', the change in the amount of fuel used in the reburning furnace 32 ', that is, the amount of exhaust gas changes greatly with the increase or decrease in dry distillation gas, and there is room for improvement in this respect.

Japanese Patent Application No. 2011-114622

  The present invention has been made in view of such a background, and while maintaining the fact that “various carbides can be produced”, which is an advantage of a conventional dry carbonization system, is maintained in a dryer. The present invention relates to a novel dry carbonization system (multi-heating system) in which the amount of heat that can be reused (recovered heat amount) is made substantially constant.

First, the dry carbonization system according to claim 1 is:
A dryer for pre-drying by heating the workpiece;
The carbonized apparatus that further heats the object to be treated after the preliminary drying, and carbonizes the carbonized carbon by distillation,
In a system for recovering heat from the carbonized exhaust gas discharged from this carbonization device, comprising a heat recovery device that is reused as a heat source for the dryer, and drying and carbonizing the workpiece,
This system is provided with an incinerator, and the path for transferring the incineration exhaust gas from the incinerator to the heat recovery device is formed so as to merge with the path for transferring the carbonization exhaust gas from the carbonization device to the heat recovery device. And
The carbonization exhaust gas from the carbonization device and the incineration exhaust gas from the incinerator are combined and sent to the heat recovery device.

Further, the dry carbonization system according to claim 2 is in addition to the requirements of claim 1,
The heat recovery device comprises a waste heat boiler that generates steam by recovering heat from a carbonization exhaust gas sent from a carbonization device or an incineration exhaust gas sent from an incinerator,

Further, the dryer comprises a hollow main body shell that accommodates an object to be processed, and a rotary heat transfer section that rotates within the main body shell,
This rotating heat transfer section is formed by equally arranging a plurality of heating tubes through which steam passes in an arc shape,
In pre-drying the object to be processed, after supplying the object to be processed into the main body shell, the rotating heat transfer section is rotated while passing the steam generated by the heat recovery device into the heating pipe, And pre-drying the workpiece by indirect heating,

The carbonization apparatus includes a carbonization furnace, and a carbonization furnace including a screw conveyor is provided in the carbonization furnace.
When carbonizing the object to be carbonized, the object to be processed is transferred in the carbonization tube while heating the carbonization tube in the carbonization furnace, and the object to be processed is carbonized by indirect heating through the carbonization tube. It is characterized by this.

Further, the dry carbonization system according to claim 3 is in addition to the requirement according to claim 2,
A part of the incineration exhaust gas discharged from the incinerator is transferred to the carbonization furnace of the carbonization apparatus.

Further, the dry carbonization system according to claim 4 is in addition to the requirement according to claim 3,
In transferring a part of the incineration exhaust gas discharged from the incinerator to the carbonization furnace, the incineration exhaust gas is diluted and transferred to the carbonization furnace.

Further, the dry carbonization system according to claim 5 is in addition to the requirement according to claim 1, 2, 3 or 4,
The incinerator is supplied with a part of the object to be processed after the preliminary drying process and incinerated.

Further, the dry carbonization system according to claim 6 is in addition to the requirement according to claim 5,
When supplying a part of the processed material after the preliminary drying process to the incinerator and incinerating,
Depending on the application of the carbide produced by the carbonization apparatus, the relationship between the ratio of the carbonized or incinerated treatment of the pre-dried material to be treated and the amount of consumed fuel oil is digitized in advance. The ratio of the carbonization treatment or the incineration treatment is determined from the desired amount of consumed fuel based on the above.

Further, the dry carbonization system according to claim 7 is in addition to the requirement according to claim 1, 2, 3, 4, 5 or 6,
The dry exhaust gas discharged from the dryer is transferred to a carbonization apparatus and an incinerator.

  First, according to the first aspect of the invention, since the carbonized exhaust gas from the carbonization device and the incineration exhaust gas from the incinerator can be combined and sent to the heat recovery device, for example, the amount of the carbonized exhaust gas sent from the carbonization device is small Even in this case, the amount can be supplemented with incineration exhaust gas sent from the incinerator. For this reason, even when the amount of carbonized exhaust gas of the carbonizer varies depending on the use of the carbide, the total amount of exhaust gas fed to the heat recovery device can be maintained almost constant, and stable heat recovery and thus stable system operation can be performed. In addition, since the total amount of exhaust gas sent to the heat recovery device is stabilized, an operation with good fuel efficiency can be performed.

  According to the invention described in claim 2, since the dry carbonization system is a system (multi-heating system) in which a conduction heat transfer dryer and a screw-type carbonization device are combined, various uses of the carbide to be produced are used. Depending on the condition, it is possible to adjust the time during which the material to be treated stays in the dry distillation pipe (time to pass through the carbonization furnace), the carbonization temperature, etc., and even one system can handle various products (carbides). Energy-saving operation can be performed.

  Further, according to the invention described in claim 3, since a part of the incineration exhaust gas discharged from the incinerator is transferred to the carbonization furnace, the incinerator performs, for example, the action of the preheating furnace in the conventional system shown in FIG. The preheating furnace which is substantially carried and exists in the conventional carbonization apparatus can be eliminated. That is, in the present invention, the incinerator provided for solving the shortage of calorific value of the carbonized exhaust gas from the carbonization apparatus can also function as a preheating furnace (preheating of the carbonization furnace) of the carbonization apparatus.

  According to the invention of claim 4, the temperature of the incineration exhaust gas from the incinerator is relatively high (850 ° C. as an example), which is suitable for preheating (preheating) of the carbonization furnace (as an example). 600.degree. C.), and efficient and stable carbonization can be performed even if the above-mentioned preheating furnace is omitted.

  According to the invention described in claim 5, in order to supply a part of the object to be treated (dried product) to the incinerator and incinerate it, for example, it is sent to a heat recovery device (waste heat boiler). The shortage of exhaust gas amount (heat amount) can be compensated by incineration (combustion) of the object to be processed. In addition, what is incinerated in the incinerator is not limited to dried products, but may be biomass such as wood chips and sawdust. However, the material balance and heat balance within this system are to be processed (dried products) after preliminary drying. Can be adjusted to save energy, which is advantageous in terms of procurement of incinerated materials and the like, and also advantageous in terms of reducing the manufacturing cost of carbides.

  According to the invention of claim 6, when the pre-dried workpiece is subjected to carbonization or incineration, the carbonized exhaust gas and the incineration exhaust gas are simply merged or the amount of carbonized exhaust gas is insufficient. In addition to the technical idea of supplementing with incineration exhaust gas, etc., it can be set up to an appropriate allocation according to the purpose of carbonization and the amount of fuel consumed in advance (percentage of pre-dried material to be carbonized or incinerated) There is an effect that driving that improves fuel consumption can be performed.

According to the seventh aspect of the present invention, the dried exhaust gas from the dryer is transferred to the carbonization device and the incinerator, and the odor components in the dried exhaust gas are burned here. Thus, odorous components generated in large quantities can be removed by combustion without using a special deodorizing furnace.
Further, since the dry exhaust gas is transferred not only to the carbonization apparatus but also to the incinerator, the amount of dry exhaust gas introduced into the carbonization apparatus can be quantified. That is, the amount of air necessary for dry distillation gas combustion is determined by the use of the carbide, and in the present invention, an appropriate amount of dry exhaust gas can be sent to the carbonizer and the surplus can be processed in an incinerator.

It is explanatory drawing which shows an example of the dry carbonization system of this invention skeletally. It is explanatory drawing which shows skeletally the carbonization apparatus which comprised the carbonization furnace and the recombustion furnace integrally. It is the side view (a) which shows a dryer partially broken, and sectional drawing (b) in this figure XX. It is a graph which shows the relationship between the ratio which carbonizes the to-be-processed object (dry product) after preliminary drying at the time of high temperature carbonization, and low temperature carbonization, and the amount of fuel oil consumed. It is explanatory drawing which shows an example of the conventional dry carbonization system skeleton.

  The mode for carrying out the present invention includes one described in the following embodiments, and further includes various methods that can be improved within the technical idea.

A dry carbonization system 1 according to the present invention performs carbonization carbonization of a workpiece W such as sewage sludge, and includes a dryer 2 (especially a conductive heat transfer dryer here) and a carbonizer 3 (especially a screw here). A carbonization apparatus), and the workpiece W pre-dried by the dryer 2 is supplied to the carbonization apparatus 3 for efficient carbonization carbonization.
Further, the exhaust gas discharged from the carbonization apparatus 3 (in this specification, this is referred to as “carbonization exhaust gas CG”) is recovered as a heat source of the dryer 2, particularly steam here, so that it can be reused.
Incidentally, conventionally, the heat source of the dryer 2 was only the carbonized exhaust gas CG discharged from the carbonization apparatus 3, but in this case, the amount of heat that can be reused fluctuates depending on the use of the carbide. A furnace 5 is also provided, and the exhaust gas discharged from the incinerator 5 (this is referred to as “incineration exhaust gas BG” in this specification) can also be reused as a heat source for the dryer 2. is there.
Therefore, the dry carbonization system 1 of the present invention includes, as an example, as shown in FIG. 1, a dryer 2, a carbonization device 3, and a heat recovery device 4 (including a waste heat boiler 41 as a main part and including a once-through boiler 42). In addition to the above, an incinerator 5 is provided, and each component will be described below.

First, the dryer 2 will be described. The dryer 2 is for preliminarily drying the workpiece W in advance in order to efficiently perform the carbonization treatment of the workpiece W as described above. When the water content of the processed product W is high, for example, it is suitable when the processed material W is sewage sludge, human waste sludge, or the like.
As shown in FIG. 3 as an example, the dryer 2 includes a hollow body shell 21 provided in a fixed state (non-rotating state), and a rotating heat transfer unit 22 rotatably supported therein. It is made up of.
The rotating heat transfer section 22 has a plurality of heating tubes 25 arranged in a circular arc shape (circumferential shape around the rotating shaft 23) between a pair of end plates 24 having a rotating shaft 23, and a tube bundle shape. It is formed by. And in order to pre-dry the to-be-processed object W with this drier 2, by rotating the rotation heat-transfer part 22 (tube bundle), flowing the steam in the heating pipe 25, the to-be-processed received in the main body shell 21 is carried out. Heat is indirectly applied to the object W (heat is added through the heating tube 25), and the object W is dried to a desired moisture content.

The rotary shaft 23 and the end plate 24 have a passage through which steam flows, and the steam is dispersed and flows into the heating tube 25 from the one rotary shaft 23 and the end plate 24. It performs heat exchange and condenses itself to drain. The drained steam is then transferred to the outside of the dryer 2 (here, the waste heat boiler 41) via the other end plate 24 and the rotating shaft 23.
Here, reference numeral 26 in the figure denotes a lifter that is provided in a protruding state so as to circumscribe the heating tube 25, and this is the object to be processed that is put into the main body shell 21 as the rotary heat transfer section 22 (tube bundle) rotates. This is for scraping up the object W.

In addition, due to the above-described configuration, the main body shell 21 is discharged with the inlets 28a (three places here) into which the workpiece W (material) is charged and the workpiece W (dried product) after the preliminary drying. A discharge port 28b is formed.
Furthermore, during pre-drying, moisture (water vapor), odor components, other volatile components, dust, etc. (dry exhaust gas) are separated and released from the workpiece W. In order to discharge, the main body shell 21 is formed with a carrier gas introduction port 29a for taking in outside air and a carrier gas discharge port 29b for discharge. That is, outside air introduced from the carrier gas introduction port 29a passes through the main body shell 21 and exits from the carrier gas discharge port 29b, moisture, odor components, other volatile components from the material to be dried W, It will accompany dust.
Although not particularly illustrated, when the moisture of the dry exhaust gas DG discharged from the carrier gas discharge port 29b is high, the condenser is used to reduce the moisture in the dry exhaust gas DG, or when there is a lot of dust, the dust collector It is also possible to reduce the dust in the dry exhaust gas DG.
Incidentally, the exhaust gas discharged from the dryer 2 (carrier gas discharge port 29b) (this is referred to as “dry exhaust gas DG” in this specification) is the carbonization apparatus 3 (carbonization furnace 31 and recombustion furnace 32) or incinerator 5. (Refer to FIG. 1).
Thus, the dryer 2 of a present Example is an indirect heating type continuous conduction heat-transfer dryer, and is also called ITR: Inner Tube Rotary (inner tube rotary).

Next, the carbonization apparatus 3 will be described. As an example, as shown in FIG. 2, the carbonization apparatus 3 includes a carbonization furnace 31 that performs substantial carbonization carbonization of the workpiece W and a carbonization gas that is released along with the carbonization carbonization process. And a re-burning furnace 32 for almost completely burning.
The carbonization furnace 31 includes a furnace body 33 and a dry distillation pipe 34. The dry distillation pipe 34 is formed so that a plurality of dry distillation paths 34R penetrate the furnace body 33 and be folded up and down. Yes. As a result, the dry distillation pipe 34 has a single continuous transfer path (pipe line) from the upper receiving port 34a (the receiving port 34a for the workpiece W) to the lower outlet 34b (the discharging port 34b for the workpiece W). ). Each dry distillation path 34R includes a screw conveyor 35, and the workpiece W is continuously transferred from the receiving port 34a to the discharge port 34b by a rotation of the screw. is there.
And in carbonizing the to-be-processed object W, the to-be-processed object W is transferred in the dry distillation pipe 34, heating the dry distillation pipe 34 from the outside in the carbonization furnace 31, and the to-be-processed object W in the furnace main body 33 is transferred. Without direct exposure to flames or combustion gases (that is, indirectly), it is heated in a low oxygen state and carbonized by carbonization.

Incidentally, the dry distillation pipe 34 is formed with a large number of dry distillation gas ejection holes 34H for discharging the dry distillation gas generated in the pipe during the carbonization treatment to the outside of the pipe (inside the carbonization furnace 31). In addition to the incinerator 5), the inside of the furnace is heated by combustion of the dry distillation gas discharged from the dry distillation gas injection hole 34H into the furnace body 33.
Further, most of the dry distillation gas released into the furnace body 33 is combusted in the carbonization furnace 31, but even if unburned gas remains, the unburned gas is regenerated in the reburning furnace 32. For this purpose, the reburning furnace 32 is provided with a burner 36.
Here, although the carbonization apparatus 3 shown in FIG. 1 is shown in a separated form in which the carbonization furnace 31 and the reburning furnace 32 are separately formed and these are connected separately by a duct or the like, the carbonization apparatus 3 is shown in FIG. As shown, an integrated structure in which a reburning furnace 32 is continuously provided above the carbonization furnace 31 is also possible.

Next, the heat recovery apparatus 4 will be described. As described above, the heat recovery device 4 recovers heat from the carbonized exhaust gas CG discharged from the carbonization device 3 or the incineration exhaust gas BG discharged from the incinerator 5, and serves as a heat source for the dryer 2. Here, Heat recovery is performed in the form of steam.
As shown in FIG. 1 as an example, the heat recovery apparatus 4 includes a waste heat boiler 41 as a main member, and further includes a once-through boiler 42 and a steam header 43.
Here, the waste heat boiler 41 exchanges heat from the exhaust gas discharged from the carbonization apparatus 3 (reburning furnace 32) and the incinerator 5, and obtains steam to be sent to the dryer 2, and the once-through boiler 42 is dried. This compensates for the shortage of heat (steam) in the machine 2. The steam header 43 is a storage unit that once collects steam supplied from the waste heat boiler 41 and the once-through boiler 42, and the steam is supplied to the dryer 2 from here. The waste heat boiler 41 and the once-through boiler 42 are supplied with water for generating steam.
For this reason, as a transfer path | route which sends steam into the dryer 2, the path | route sent from the waste heat boiler 41 via the steam header 43 to the dryer 2 and the path | route sent from the once-through boiler 42 via the steam header 43 to the dryer 2 are included. It exists. The steam is sent from the once-through boiler 42 to the steam header 43, for example, when the heat recovery from the waste heat boiler 41 cannot be sufficiently performed at the start of the dry carbonization system 1 or from the waste heat boiler 41 for some reason during operation. For example, when the amount of heat decreases.
Incidentally, although not shown in particular, the steam supplied from the steam header 43 to the dryer 2 gives heat to the workpiece W and becomes drain, and this is used as a path of water supplied to the waste heat boiler 41. The waste heat boiler 41 circulates and uses it again as steam.

Next, the incinerator 5 will be described. As shown in FIG. 1 as an example, the incinerator 5 has a generally cylindrical shape, but the upper portion of the main body is formed in a constricted shape. The incinerator 5 is configured such that the incinerator can be uniformly burned by stirring the top of the hearth with a stirring rod 51 that stirs the incinerated ash accumulated on the hearth.
Here, as the incineration object, for example, a part of the workpiece W preliminarily dried by the dryer 2 can be applied, and the incineration object is put into the incinerator 5 from the furnace wall by the screw conveyor 52 or the like. Further, the incineration ash generated by the incineration process in the furnace moves to the center of the hearth by the action of the stirring rod 51, and is discharged out of the incinerator 5 from here through the screw conveyor 53. Here, reference numeral 54 in the figure denotes a burner provided in the incinerator 5.
Note that the incineration exhaust gas BG released from the incineration object in accordance with the incineration process is discharged from the upper part of the main body of the incinerator 5 and transferred to the waste heat boiler 41 and the carbonization furnace 31. Although not specifically shown, a temperature sensor is provided at the upper part of the main body of the incinerator 5, the temperature of the incineration exhaust gas BG is detected by this sensor, and the combustion state of the burner 54 is automatically controlled.

Next, characteristic passages and the like in this embodiment, such as a transfer route of exhaust gas discharged from the carbonization apparatus 3 and the incinerator 5, will be described.
First, in the present invention, the carbonization exhaust gas CG from the carbonization apparatus 3 and the incineration exhaust gas BG from the incinerator 5 are merged and then transferred to the waste heat boiler 41. That is, not only the path for feeding the carbonized exhaust gas CG from the carbonization device 3 (reburning furnace 32) to the waste heat boiler 41 but also the path for feeding the incineration exhaust gas BG from the incinerator 5 to the waste heat boiler 41 is formed. These are formed so as to merge before the waste heat boiler 41. A part of the incineration exhaust gas BG discharged from the incinerator 5 is also transferred to the carbonization furnace 31.
Thereby, for example, when the calorific value of the carbonized exhaust gas CG sent from the carbonization device 3 to the waste heat boiler 41 is small, the heat amount of the incineration exhaust gas BG sent from the incinerator 5 to the waste heat boiler 41 is increased, and the waste heat boiler 41 receives it. The total amount of heat can be made almost constant. Specifically, for example, when the dry carbonization system 1 of the present invention is started, the amount of heat necessary for raising the temperature of the carbonization furnace 31 is sent from the incinerator 5 to the carbonization furnace 31 as incineration exhaust gas BG, and also to the waste heat boiler 41. The amount of heat necessary for raising the temperature of the waste heat boiler 41 can be sent as the incineration exhaust gas BG. Thereby, the waste heat boiler 41 can be brought into a steady operation state in a short time from the start-up, and the steam generated in the waste heat boiler 41 can be used in the dryer 2 in a short time from the start-up. That is, the incineration exhaust gas BG from the incinerator 5 is merged with the carbonization exhaust gas CG from the recombustion furnace 32 and sent to the waste heat boiler 41, so that the carbonization furnace 31, the waste heat boiler 41, and the dryer 2 are made in a short time. The configuration is suitable for starting up.
In addition, it is preferable to provide the damper 55 which adjusts exhaust gas flow volume in the path | route which transfers the incineration waste gas BG to the waste heat boiler 41, as it shows in FIG. Incidentally, if a pressure sensor 56 for detecting the pressure of the incineration exhaust gas BG discharged therefrom is provided at the exhaust gas discharge port portion of the incinerator 5, the opening degree of the damper 55 is automatically set based on the measured value of the pressure sensor 56. It is possible to make adjustments.

Further, as described above, a part of the incineration exhaust gas BG discharged from the incinerator 5 is transferred to the carbonization apparatus 3 (carbonization furnace 31), and thereby the incineration exhaust gas BG of the incinerator 5 is converted into the carbonization furnace 31. It can also be used as a heating source. Therefore, in this case, the incinerator 5 can also be used as a preheating furnace H (see FIG. 5) of the conventional carbonization apparatus 3 ′, and the conventional preheating furnace H becomes unnecessary.
When a part of the incineration exhaust gas BG is sent to the carbonization device 3 (carbonization furnace 31), the incineration exhaust gas BG has a high temperature. For example, a damper 57 is provided as shown in FIG. It is preferable to send the exhaust gas BG diluted with outside air.
Here, the opening degree of the damper 57 is adjusted so as to be a temperature required according to the purpose of carbonization such as manufacturing fertilizer and fuel. Although not particularly illustrated, for example, after the outside air sucked in from the damper 57 and the incineration exhaust gas BG merge, the temperature of the gas in the path entering the carbonization furnace 31 is measured by a temperature sensor, and the damper 57 according to the temperature is measured. The opening is adjusted. Further, as the temperature sensor for controlling the opening degree of the damper 57, in addition to the above, for example, a temperature sensor that measures the product temperature of the carbide (the workpiece W) at the discharge port 34b of the dry distillation pipe 34 may be used. A temperature sensor that measures the temperature of the carbonized exhaust gas CG flowing from 31 to the reburning furnace 32 may be used.
For example, as shown in FIG. 1, if a damper 58 is provided in the path for transferring the incineration exhaust gas BG from the incinerator 5 to the carbonization furnace 31, carbonization can be achieved by adjusting the flow rate of the incineration exhaust gas BG with this damper 58. The amount of heat of the gas introduced into the furnace 31 can be adjusted with higher accuracy.

Further, a part of the workpiece W preliminarily dried by the dryer 2 can be put into the incinerator 5 and incinerated, which is insufficient in the amount of heat held by the exhaust gas transferred to the waste heat boiler 41. In this case, this shortage can be replenished.
In addition, although the wood chip, sawdust, etc. can be applied as the object (incinerator) to be incinerated in the incinerator 5, if a part of the pre-dried object W is applied, the dry carbonization system of the present invention. Since the material balance and the heat balance can be adjusted so as to save energy in 1, it is not necessary to take time to procure incineration objects such as wood chips, which is highly convenient.
Of course, if biomass fuel is used separately, it is possible to improve fuel efficiency without incineration of dried products (such as the pre-dried workpiece W).

The dry carbonization system 1 of the present invention has the basic structure as described above. Hereinafter, an operation mode in which the workpiece W such as sewage sludge is carbonized by this system will be described. In the description, the description will be divided into “flow of object to be treated”, “flow of dry exhaust gas”, “flow of carbonized exhaust gas”, “flow of incineration exhaust gas”, “flow of steam”, and the like.
(1) Flow of the object to be processed The object W to be processed is supplied to the dryer 2 containing, for example, a lot of moisture (indicated as “material” in FIGS. 1 and 5), and passes through the heating tube 25 here. After being pre-dried by indirect heat exchange with the steam to be transferred, it is transferred to the carbonization furnace 31. And the to-be-processed object W supplied to the carbonization furnace 31 is indirectly heated via the dry distillation pipe 34, passing through the dry distillation pipe 34 in which the screw conveyor 35 is incorporated, and subjected to dry distillation carbonization treatment.
A part of the workpiece W preliminarily dried by the dryer 2 (denoted as “dried product” in FIGS. 1 and 5) can be supplied to the incinerator 5 and incinerated. The to-be-processed object W is incinerated with the furnace 5, and high temperature incineration waste gas BG arises.

(2) Flow of dry exhaust gas During the preliminary drying in the dryer 2, the dry exhaust gas DG separated and released from the workpiece W (denoted as “dry exhaust” in FIGS. 1 and 5) is contained in the workpiece W. Therefore, this is introduced into the carbonization apparatus 3 (carbonization furnace 31 / reburning furnace 32) or incinerator 5 to burn and deodorize. Thereby, it is possible to deodorize the dry exhaust gas DG without using a special and combustion deodorization furnace.
The dry exhaust gas DG supplied to the carbonization apparatus 3 is also used for combustion of the dry distillation gas released from the workpiece W during the carbonization carbonization process. Further, the dry exhaust gas DG supplied to the incinerator 5 is also used for incineration of an incineration object (here, a part of the object to be processed W).
Further, since the dry exhaust gas DG is sent not only to the carbonization furnace 31 but also to the incinerator 5 and the reburning furnace 32, the amount of dry exhaust gas introduced into the carbonization furnace 31 can be quantified. Can be stabilized. That is, the amount of air necessary for combustion of the dry distillation gas is determined by the use of the carbide, and in this embodiment, the dry exhaust gas DG can be sent to the carbonization furnace 31, the incinerator 5, or the reburning furnace 32. An appropriate amount of the dry exhaust gas DG can be sent to the carbonization furnace 31 and the surplus can be sent to the incinerator 5.

(3) Flow of carbonized exhaust gas The carbonized exhaust gas CG discharged from the carbonization apparatus 3 (recombustion furnace 32) has almost completely removed dry distillation gas by combustion in the recombustion furnace 32. As an example, about 800 ° C to 850 ° C Temperature. The carbonized exhaust gas CG is then transferred to the waste heat boiler 41 where heat is recovered as steam. The exhaust gas (carbonized exhaust gas CG), which has been lowered in temperature by heat exchange in the waste heat boiler 41, is discharged into the atmosphere after passing through an exhaust facility such as a bag filter. Reference numerals 61 and 62 are a blower and a damper for this purpose.
Here, the control of the damper 62 will be described. For example, a pressure sensor 63 is provided at the exhaust gas discharge port of the reburning furnace 32, and the damper 62 is controlled so that the pressure detected by the pressure sensor 63 becomes an appropriate value. It controls the opening.
Although not shown in particular, when it is desired to adjust the flow rate of the carbonized exhaust gas CG transferred from the reburning furnace 32 to the waste heat boiler 41, a part of the carbonized exhaust gas CG discharged from the reburning furnace 32 is subjected to appropriate safety measures. However, it may be discharged to the atmosphere without passing through the waste heat boiler 41.

(4) Flow of incineration exhaust gas A part of the incineration exhaust gas BG discharged from the incinerator 5 is transferred to the waste heat boiler 41, and a part thereof is transferred to the carbonization furnace 31.
First, the incineration exhaust gas BG transferred to the waste heat boiler 41 merges with the carbonization exhaust gas CG from the carbonization apparatus 3 and is transferred to the waste heat boiler 41 where heat is recovered as thermal energy for generating steam. is there. In the present invention, only the carbonized exhaust gas CG is not sent to the waste heat boiler 41, but can be sent to the waste heat boiler 41 together with the incineration exhaust gas BG. Therefore, the calorific value of the carbonized exhaust gas CG increases or decreases depending on the use of the carbide. However, the increase / decrease amount can be adjusted by the incineration exhaust gas BG discharged from the incinerator 5. Therefore, the total amount of heat received by the waste heat boiler 41 can be made constant, and stable heat recovery can be performed. When adjusting the amount of exhaust gas of the incineration exhaust gas BG transferred to the waste heat boiler 41, the pressure in the incinerator 5 is detected by the pressure sensor 56 provided near the upper part of the main body of the incinerator 5 as described above. The detected value is used to control and adjust the opening degree of the damper 55.
The incineration exhaust gas BG transferred to the carbonization furnace 31 is used as a heating source for the carbonization furnace 31. In this case, since the incineration exhaust gas BG has a high temperature, the incineration exhaust gas BG is appropriately diluted by the damper 57 and adjusted to a temperature suitable for the intended carbonization and transferred. In addition, the conventional preheating furnace H becomes unnecessary by utilizing a part of the incineration exhaust gas BG as a heating source of the carbonization furnace 31.

(5) Steam flow Steam obtained by heat recovery from the carbonized exhaust gas CG and the incineration exhaust gas BG in the waste heat boiler 41 is once sent to the steam header 43 and supplied to the dryer 2 from here. The In addition, the steam produced | generated with the once-through boiler 42 as mentioned above is also sent to this steam header 43, and is sent to the dryer 2 similarly after that. Then, the steam sent to the dryer 2 indirectly exchanges heat with the workpiece W while passing through the heating pipe 25, becomes itself drained, and then enters the path of water supplied to the waste heat boiler 41. It joins and becomes steam again in the waste heat boiler 41 (circulated and used).

The present invention uses the above-described embodiment as one basic technical idea, and further exhibits the following functions.
In the above-described embodiments, the description has mainly been made of joining the transfer paths of the carbonized exhaust gas CG and the incineration exhaust gas BG, and supplementing the shortage of the carbonized exhaust gas CG with the incineration exhaust gas BG. However, it is also possible to more positively determine the merging ratio of the carbonized exhaust gas CG and the incineration exhaust gas BG, that is, the processing ratio at which the dried product (the pre-dried workpiece W) is subjected to carbonization and incineration. There will be described below with reference to FIG.
The horizontal axis of the graph shown in FIG. 4 indicates the ratio of subjecting it to carbonization when the total amount of the workpieces W (dried products) that have been subjected to the preliminary drying process in the dryer 2 is 1. Specifically, it is the ratio at which the dry product is charged into the carbonization apparatus 3, and is shown in the form (fraction) of (carbonization treatment amount / dry product total amount). “0” indicates a case where the ratio of carbonization is zero, that is, all dry products are incinerated. Further, “1” at the right end of the horizontal axis of the graph indicates a case where all the dried products are carbonized.
In addition, the vertical axis of the graph indicates the amount of fuel consumed in the burner 36 and the burner 54 when the carbonization process or the incineration process is performed at the above ratio.

In addition, two lines (straight lines) drawn in the graph indicate the time of low-temperature carbonization on the upper side, and are an example in the case of carbonizing a dried product (processing object W) for the purpose of fertilizer or fuel, for example. On the other hand, the lower line (straight line) indicates high temperature carbonization. For example, the purpose of carbonization is to change the dry product W to be as close to carbon as possible, or to reduce the dry product W volume. This is an example of a case where the waste is treated as waste.
Here, for example, in the case of high-temperature carbonization, in view of the amount of heat that can be used by burning the dried workpiece W in the incinerator 5, the production amount of carbide produced by the carbonization apparatus 3, and the price of the carbide, the consumed fuel oil If the amount is approximately 200 liters / hour (that is, if the amount of fuel to be used is limited to this value), the processing rate should be about 0.8, as indicated by the broken line on the graph. I understand. That is, an appropriate treatment ratio can be set in advance, in which 80% of the dried product is supplied to the carbonization apparatus 3 for carbonization, and the remaining 20% is supplied to the incinerator 5 for incineration. Thus, here, the relationship between the amount of fuel oil consumed and the rate of carbonization or drying treatment of the pre-dried workpiece W is numerically represented by a graph. These relationships can be obtained by operating the dry carbonization system 1 on a trial basis.

In addition, although the line which shows the relationship between the amount of fuel oil consumed and a process rate was drawn in two cases, low temperature carbonization and high temperature carbonization, in FIG. 4, various lines are actually assumed according to the use etc. of carbide. The However, as described above, whether or not to incinerate and an appropriate ratio (a ratio to be used for incineration or carbonization) can be examined in advance based on such a line, thereby enabling operation to improve fuel consumption. It is.
Further, in the embodiment shown in FIG. 1, the amount of carbonized exhaust gas CG sent from the carbonizer 3 (reburning furnace 32) to the waste heat boiler 41 and the incineration exhaust gas BG sent from the incinerator 5 to the waste heat boiler 41 are used. The quantity is a configuration that can be controlled independently. That is, in the embodiment shown in FIG. 1, when the pre-dried workpiece W is subjected to carbonization or incineration, the carbonization exhaust gas CG and the incineration exhaust gas BG are simply joined together, or the carbonization exhaust gas CG (flow rate) In addition to technical ideas such as supplementing with incineration exhaust gas BG when the amount of heat is insufficient, appropriate allocation according to the purpose of carbonization and the amount of fuel consumed in advance (carbonization or incineration of the pre-dried workpiece W) The ratio is also set up to the ratio for processing.

DESCRIPTION OF SYMBOLS 1 Drying carbonization system 2 Drying machine 3 Carbonization apparatus 4 Heat recovery apparatus 5 Incinerator

2 Dryer 21 Body shell 22 Rotating heat transfer section (tube bundle)

21 body shell 28a inlet 28b outlet 29a carrier gas inlet 29b carrier gas outlet

22 Rotating heat transfer section (tube bundle)
23 Rotating shaft 24 End plate 25 Heating tube 26 Lifter

3 Carbonization equipment 31 Carbonization furnace 32 Reburning furnace

31 Carbonization furnace 33 Furnace main body 34 Carbonization pipe 34R Carbonization path 34a Inlet (for workpiece)
34b Discharge port (to be processed)
34H Carbon Distillation Hole 35 Screw Conveyor

32 Reburning furnace 36 Burner

4 heat recovery equipment 41 waste heat boiler 42 once-through boiler 43 steam header

5 Incinerator 51 Stirring Rod 52 Screw Conveyor 53 Screw Conveyor 54 Burner 55 Damper 56 Pressure Sensor 57 Damper 58 Damper

61 Blower 62 Damper 63 Pressure sensor

W Object to be processed (material, dry product)
H Preheating furnace

DG Dry exhaust gas CG Carbonization exhaust gas BG Incineration exhaust gas

Claims (7)

A dryer for pre-drying by heating the workpiece;
The carbonized apparatus that further heats the object to be treated after the preliminary drying, and carbonizes the carbonized carbon by distillation,
In a system for recovering heat from the carbonized exhaust gas discharged from this carbonization device, comprising a heat recovery device that is reused as a heat source for the dryer, and drying and carbonizing the workpiece,
This system is provided with an incinerator, and the path for transferring the incineration exhaust gas from the incinerator to the heat recovery device is formed so as to merge with the path for transferring the carbonization exhaust gas from the carbonization device to the heat recovery device. And
A dry carbonization system configured to combine the carbonized exhaust gas from the carbonization apparatus and the incineration exhaust gas from the incinerator into a heat recovery apparatus.
The heat recovery device comprises a waste heat boiler that generates steam by recovering heat from a carbonization exhaust gas sent from a carbonization device or an incineration exhaust gas sent from an incinerator,

Further, the dryer comprises a hollow main body shell that accommodates an object to be processed, and a rotary heat transfer section that rotates within the main body shell,
This rotating heat transfer section is formed by equally arranging a plurality of heating tubes through which steam passes in an arc shape,
In pre-drying the object to be processed, after supplying the object to be processed into the main body shell, the rotating heat transfer section is rotated while passing the steam generated by the heat recovery device into the heating pipe, And pre-drying the workpiece by indirect heating,

The carbonization apparatus includes a carbonization furnace, and a carbonization furnace including a screw conveyor is provided in the carbonization furnace.
When carbonizing the object to be carbonized, the object to be processed is transferred in the carbonization tube while heating the carbonization tube in the carbonization furnace, and the object to be processed is carbonized by indirect heating through the carbonization tube. The dry carbonization system according to claim 1.
The dry carbonization system according to claim 2, wherein a part of the incineration exhaust gas discharged from the incinerator is transferred to a carbonization furnace of a carbonization apparatus.
4. The dry carbonization system according to claim 3, wherein when transferring a part of the incineration exhaust gas discharged from the incinerator to the carbonization furnace, the incineration exhaust gas is diluted and transferred to the carbonization furnace.
The dry carbonization system according to claim 1, 2, 3 or 4, wherein the incinerator is supplied with a part of an object to be treated after the preliminary drying treatment and incinerated.
When supplying a part of the processed material after the preliminary drying process to the incinerator and incinerating,
Depending on the application of the carbide produced by the carbonization apparatus, the relationship between the ratio of the carbonized or incinerated treatment of the pre-dried material to be treated and the amount of consumed fuel oil is digitized in advance. 6. The dry carbonization system according to claim 5, wherein a ratio of the carbonization treatment or the incineration treatment is determined based on a desired fuel consumption amount.
  The dry carbonization system according to claim 1, 2, 3, 4, 5 or 6, wherein the dry exhaust gas discharged from the dryer is transferred to a carbonization device and an incinerator.

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