TWI554736B - Multi - stage organic drying system - Google Patents

Description

Multi-stage organic drying system

The present invention relates to a multi-stage organic matter drying system, and more particularly to a multi-stage organic matter drying system used for drying an organic substance containing a large amount of water such as sludge.

In order to dry an organic substance containing a large amount of water such as sludge, a multi-stage organic matter drying system in which organic matters are transported from the upper layer to the lower layer and the superheated steam is blown to dry the organic matter is proposed.

As shown in Patent Document 1, the organic material is configured to be conveyed in the lateral direction by a plurality of stirring crucibles arranged in each layer and formed to rotate, and the end layer of each layer is down to the next layer, and then continues. The mixing layer of the lower layer is conveyed in the lateral direction. In this way, the organic matter is transported from the upper layer to the lower layer in multiple stages. Next, the heated gas is moved (cocurrently) in the same direction as the "transport direction of the organic matter" to form a drying of the organic matter.

Further, Patent Document 2 discloses that in the final step (dry end period) of the organic material transport means, it is contacted with the vaporized vapor having a small amount of air to compensate for insufficient drying, and the dust is prevented from being mixed into the steam, thereby suppressing the dust collecting device. The technology of large-scale.

The relationship between the direction in which the organic matter is transported and the direction in which the superheated vapor flows is not limited to the "cocurrent mode" in which the two are moving in the same direction, and there is also a "communication (countercurrent) in which the two move in opposite directions to each other. Flow))). Although the parallel flow method has the advantage of so-called temperature control stability, as shown in Patent Document 1, there is a problem that the end heating is insufficient. Although the alternating current method has high thermal efficiency and can carbonize the organic matter, the heating tends to be localized, and the so-called overall temperature control is not easy.

Further, the parallel flow method and the alternating current method are combined, and the superheated steam is supplied to the intermediate position of the transport path, and the superheated vapor is flowed on the upstream side by the alternating current method with respect to the transport direction of the organic substance, and the downstream side is caused by the parallel flow method. The superheated vapor flows, and the so-called "two-split method" drying method is utilized. However, in a multi-stage organic drying system, the upper layer requires high temperature and the lower layer requires low temperature drying. Therefore, in the two-split system, since the superheated steam temperature at the inlet of the dryer is a single temperature, it is difficult to simultaneously satisfy the conditions on the upstream side and the conditions on the downstream side, and it is difficult to have inefficiency and difficulty in operation control.

Further, in the case where the flow path is formed only by the cocurrent mode or the alternating current mode or the flow path is formed by only the two-way flow method, the flow path becomes too long, so that the temperature responsiveness of the superheated steam is poor. There is a problem that it is easy to cause so-called excessive drying or insufficient drying. Further, an excessively long flow path causes an increase in the internal pressure loss, and a problem that the circulation fan is enlarged is also caused.

Even in the case of performing drying of a low-temperature heat source (exhaust gas of about 300 ° C), the heat transfer area is increased, and in the case of a superheated steam circulation type dryer, in order to make the flow rate of the circulating steam become the generated vapor flow rate. It is about 12 to 15 times, and the flow rate inside the dryer is likely to become excessively large, causing problems such as dust scattering.

[Previous Technical Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 2-71900

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2004-190990

An object of the present invention is to provide a problem that can eliminate the above problems, and that the overall temperature control is easy and the heat utilization efficiency is high, and even in the case of using a low-temperature heat source, the flow rate of the superheated steam can be prevented from becoming excessive. Multi-stage organic drying system.

In order to solve the above problems, the multi-stage organic matter drying system of the present invention has the following technical features.

(1) A multi-stage organic substance having a conveying means for "transporting organic matter from the upper layer to the lower layer" and a drying chamber for accommodating the conveying means, and blowing the superheated steam to the drying chamber to dry the organic substance The drying system is characterized in that: N (N is a natural number of 2 or more), an introduction port for introducing superheated steam into the drying chamber, and N±1 outlets for discharging superheated steam from the drying chamber.

(2) The multi-stage organic drying system according to the above (1), wherein the inlet and the outlet are arranged to be shifted from each other in the height direction, and superheated steam introduced from the inlet is formed: flow direction The air flow in the opposite direction to the transport direction of the transport means and the air flow in the same direction as the transport direction of the transport means.

(3) The multi-stage organic matter drying system according to (1) or (2) above, wherein the N inlet ports are introduced with superheated steam having different temperatures.

(4) The multi-stage organic matter drying system according to the above (3), characterized in that the temperature of the superheated steam introduced from the inlet is 45% or less in the water content of the organic matter treated by the superheated steam. In this case, it is set to 250 ° C or less.

In the multi-stage organic matter drying system of the present invention, there are N (N is a natural number of 2 or more) for introducing superheated steam into the introduction port of the drying chamber, and N±1 for superheated steam from the drying chamber. Since the outlet port is led out, the flow path of the superheated steam can be made short, and the part of the parallel flow mode and the alternating current mode can be appropriately set in the middle of the organic material transfer path, and the temperature control can be easily performed. The heat utilization efficiency of the superheated steam is set to be high. In addition, the flow rate of the superheated steam can also be suppressed.

In addition, in the case where the number of the outlets is N-1, the superheated steam easily stays in the drying chamber, and the pressure of the superheated steam is increased, so that the heat capacity of the superheated steam can be increased. Further, in the case where the number of the outlets is N+1, the flow of the superheated steam can be smoothed, and the circulation of the superheated steam can be efficiently performed.

In addition, the inlet port and the outlet are arranged to be shifted from each other in the height direction, and the superheated steam introduced from the inlet port forms an air flow (communication method) flowing in the "direction opposite to the conveying direction of the conveying means". The air flow (cocurrent mode) flowing in the "direction in the same direction as the transport direction of the transport means" allows each layer to use an alternating current method and a parallel flow method, respectively, and the heat utilization efficiency can be improved. Further, in the case where the number of the outlets is N-1, since the upper layer side starts from the parallel flow mode and the lower layer side ends by the alternating current method, the superheated steam is less likely to leak, especially since the lower layer is an alternating current mode. Therefore, it is possible to suppress the case where "the dust from the dried organic matter is largely exported to the outlet". Further, in the case where the number of the outlets is N+1, since the alternating current method is formed on the upper layer side, the organic matter can be efficiently dried, and the parallel flow mode can be formed on the lower layer side, whereby the temperature control can be easily performed.

Further, since superheated vapors having different temperatures from each other are introduced into the N introduction ports, it is possible to provide superheated steam corresponding to the optimum temperature of each layer, and it is easy to control the temperature.

In addition, in the case where the water content of the organic material to be treated by the superheated steam is 45% or less, the temperature of the superheated steam introduced from the inlet is set to 250 ° C or lower, so that excessive drying of the organic substance can be suppressed.

Although the present invention has been described by way of the following preferred examples, the invention is not limited by the description.

The multi-stage organic drying system of the present invention is a conveying means (each layer is shown in FIG. 4) for "transporting organic substances containing moisture such as sludge from the upper layer to the lower layer", and a drying chamber for accommodating the conveying means. And a multi-stage organic drying system for blowing the superheated steam (a to c) into the drying chamber, wherein the organic material is dried, and is characterized in that: the superheated steam (a to c) is introduced into the drying chamber 1 N (N is a natural number of 2 or more) introduction ports (21 to 23) and N±1 outlets (31, 32) for discharging superheated steam (d, e) from the drying chamber 1.

As a conveying means used in the multi-stage organic drying system of the present invention, as shown in Fig. 2, a plurality of stirring crucibles 8 are disposed on the conveying platform 4 of each layer, and the rotating shafts are arranged to penetrate the respective layers. 9 is constructed by rotating each stirring crucible 8. Fig. 2(a) is a plan view of the stirring crucible disposed in each layer, and Fig. 2(b) is a side view seen from the lateral direction. The organic matter is sequentially conveyed in the direction of arrows A and B by the rotation of each stirring crucible. The conveying means is not limited to the stirring crucible shown in Fig. 2, and the "conveying means based on continuous belt" may be used. In order to increase the contact area between the organic substance and the superheated steam, it is preferable to use an additional stirring. The means of transporting the stirring function.

As shown in Fig. 1, the organic matter is sequentially transported from the upper layer in the drying chamber to the lower layer, and is dried by "superheated steam introduced into the drying chamber", and finally dried as an organic substance such as dried sludge. (dry organic matter) and discharged. The dried organic matter is incinerated by a combustion furnace or incinerated as a fuel for cement manufacturing equipment.

In the multi-stage organic drying system of the present invention, it is preferred to recycle the superheated steam. This is because it is possible to suppress the "odor generated when the organic matter such as sludge is dried" to be discharged to the outside, and to effectively utilize the heat retained by the superheated steam. As shown in Fig. 1, in the drying chamber 1, superheated steam (a to c) is introduced from the inlets (21 to 23) and discharged from the outlets (31, 32), and the discharged superheated steam (circulating vapor) The figure numbers d and e) are blown by the fans (51, 52) (f, g), heated by the heat exchangers (61, 62), and again become superheated vapors (a to c) and are introduced. Drying chamber 1.

Once the organics are dried, steam is produced and mixed into the superheated vapor. Therefore, since the pressure of the superheated vapor rises, the unnecessary vapor will be discharged to the outside as the remaining vapor (vapor evaporated from the organic matter). At this time, by using the remaining steam for "a part of the air supplied to the incinerator or the cement manufacturing facility", the remaining steam can be treated at a high temperature to decompose and remove the odor contained in the vapor.

In the heat exchangers (61, 62), high-temperature exhaust gas such as combustion gas discharged from a combustion furnace or a cement manufacturing facility is introduced. In the multi-stage organic drying system of the present invention, even when the heating gas such as the combustion gas introduced into the heat exchanger is a low-temperature heat source having a temperature of about 300 ° C, there is no superheated steam inside the drying chamber. The flow rate becomes too large.

The multi-stage organic matter drying system of the present invention has N (N is 2 or more natural numbers) introduction ports for introducing superheated steam into the drying chamber, and N±1 guides for deriving superheated steam from the drying chamber. Export. By arranging the introduction ports for introducing the superheated steam into two or more, the flow passage of the superheated steam introduced from one introduction port can be set to be short. Further, since the number of the outlets is one less than the number of the inlets, and the portion of the cocurrent mode or the alternating current mode can be appropriately set in the middle of the organic material conveying path, the temperature control is easy to perform and overheating The heat utilization efficiency of the vapor can also be set to be high.

In addition, in the case of using a low-temperature heat source, even if the amount of superheated steam (circulating steam) is 12 to 15 times the amount of vaporized vapor evaporated from the organic matter, the flow path through which each superheated steam passes can be shortened. Since the vapor passage area is suppressed, there is no possibility that the flow rate of the superheated steam becomes excessive.

Further, in the case where the number of the outlets is N-1, since the number of the outlets is smaller than the number of the inlets, the superheated vapor is liable to stay in the drying chamber, and the pressure of the superheated steam is increased, and the superheated steam can be increased. Drying of heat capacity. Further, in the case where the number of the outlets is N+1, since the number of the outlets is smaller than the number of the inlets, the flow of the superheated steam can be smoothed, and the circulation of the superheated vapor can be efficiently performed. .

Further, in the multi-stage organic drying system of the present invention, the inlets (21 to 23) and the outlets (31, 32) are arranged to be shifted from each other in the height direction, and are introduced from the inlet. The superheated steam forms an air flow (communication method) flowing in the "direction opposite to the transport direction of the transport means" and an air flow (cocurrent mode) flowing in the "direction in the same direction as the transport direction of the transport means". It is possible to use the alternating current mode and the parallel flow mode for each layer, which can further improve the heat utilization efficiency.

Further, in the case where the number of the outlets is N-1, since the upper layer side starts from the parallel flow mode and the lower layer side ends by the alternating current method, it is possible to suppress the superheated steam from reaching the organic substance inlet or the discharge port. external. In particular, since the lower layer is in an alternating current mode, it is possible to suppress the dust from the dried organic matter from being largely discharged to the outlet. Of course, in the case where dust or the like is easily mixed with the superheated steam, a dust collector such as a cyclone dust collector may be disposed in the middle of the circulation path (Fig. e or d) of the superheated steam.

Further, in the case where the number of the outlets is N+1, the alternating current mode is formed on the upper layer side, the organic matter can be efficiently dried, and the parallel flow mode can be formed on the lower layer side, and temperature control can be easily performed.

The multi-stage organic matter drying system of the present invention is configured to introduce superheated vapors having different temperatures from each other at the N inlets. When a low-temperature heat source is used, as shown in Fig. 1, a superheated steam having a high temperature of about 280 ° C or higher or about 280 ° C is introduced into the inlet 21 of the upper layer, and the inlet 22 of the intermediate layer is introduced at 260 ° C or higher, or 260. The superheated steam at a moderate temperature of about °C is introduced into the lower inlet port 23 to introduce a superheated vapor having a low temperature of about 220 ° C or higher or about 220 ° C.

Preferably, as described above, the temperature of the introduced superheated vapor is lowered from the upper layer toward the lower layer. This is because the amount of moisture in the organic matter decreases toward the lower layer. In particular, when the temperature of the superheated steam introduced from the inlet is 45% or less in the case where the moisture content of the organic material treated by the superheated steam is 45% or less, it is preferably 250 ° C or lower. This is to suppress the occurrence of dry distillation in which "the volatile components contained in the organic matter are evaporated", and excessive drying such as coal char (tar) is generated in the vapor.

The superheated steam (d, e) which loses heat by drying the organic matter is discharged from the outlets (31, 32). The temperature of the superheated steam is a temperature of about 140 ° C or higher or about 140 ° C. In order to improve the heat utilization efficiency, it is reheated as a circulating steam and supplied as new superheated steam (a to c).

In order to adjust the temperature in the drying chamber 1, it is necessary to adjust the flow rate and temperature of the superheated steam entering the drying chamber. Therefore, there is a method of "adjusting the temperature of the heating gas such as the combustion gas introduced into the heat exchanger" or "a method of adjusting the flow rate of the superheated steam passing through the heat exchanger". In addition, by changing the passage path or the flow rate of the superheated steam g introduced into the heat exchanger by operating the baffle 7, the flow ratio between the superheated steam a at a high temperature and the superheated steam c at a low temperature can be changed. Way to control the temperature of the drying chamber. In the first drawing, the heating gas such as the combustion gas is introduced into the other heat exchanger 62 by the heating gas used by the heat exchanger 61. However, it is not limited thereto, and it is also possible for each heat exchanger. Introduce different heating gases.

In the multi-stage organic matter drying system of the present invention, even when a low-temperature heat source having a low industrial value of 300 ° C or less is used, in the first drawing, four superheated steam flow paths are secured (introduction port 21 → The outlet 31, similarly, four flow paths of 22→31, 22→32, and 23→32 can shorten the flow path and suppress an increase in the flow rate, so that the dryer main body and the heat exchanger can be miniaturized.

Since the execution of "dispensing the transport path of the organic matter into a plurality of and contacting with the superheated vapor", that is, the so-called split treatment, the temperature control at the inlet or the outlet of the drying chamber of the superheated steam is facilitated, and stable formation can be achieved. dry. Further, as shown in Fig. 1, in the multi-stage dryer of 13 layers (the number of effective layers is 12 layers because the superheated steam does not pass through the first layer of the upper layer), if four vapor flow paths are formed, Since there are three layers per vapor flow path, the temperature response can be improved compared to the conventional technique of treating "a degree of each vapor flow path of more than ten layers", and the internal flow rate can also become one flow path. In the case of 1/4 of the mode, the size can be reduced, and scattering of dust or the like can be suppressed.

[industrial use]

As described above, the present invention can provide a multi-stage organic matter drying system capable of suppressing the flow rate of the superheated steam to be excessive, even when the low-temperature heat source is used, because the temperature control is easy and the heat utilization efficiency is high.

1. . . Drying room

21~23. . . Guide

31, 32. . . Outlet

4. . . Transport platform

51, 52. . . Air supply fan

61, 62. . . Heat exchanger

7. . . Baffle

8. . . Stir

9. . . Rotary axis

a~e. . . Superheated steam

Fig. 1 is a view showing the outline of a multi-stage organic drying system of the present invention.

Fig. 2 is a view showing one of the conveying means used in the multi-stage organic drying system of the present invention.

a~g. . . Superheated steam

1. . . Drying room

4. . . Transport platform

7. . . Baffle

21~23. . . Guide

31, 32. . . Outlet

51, 52. . . fan

61, 62. . . Heat exchanger

Claims (3)

A multi-stage organic drying system is a multi-stage type having a conveying means for conveying an organic substance from an upper layer to a lower layer and a plurality of stages, and a drying chamber for accommodating the conveying means, and blowing the superheated steam to the drying chamber to dry the organic substance. An organic drying system characterized by having N (N is 2 or more natural numbers) introduction ports for introducing superheated steam into the drying chamber, and N±1 for discharging superheated steam from the drying chamber The outlets are introduced with superheated vapors having different temperatures from each other at the N inlets. The multi-stage organic drying system according to the first aspect of the invention, wherein the inlet and the outlet are arranged to be shifted from each other in a height direction, and superheated steam introduced from the inlet is formed: a flow direction and the conveyance The air flow in the opposite direction of the transport direction of the means and the air flow in the same direction as the transport direction of the transport means. The multi-stage organic drying system according to claim 1 or 2, wherein the temperature of the superheated steam introduced from the inlet is such that when the moisture content of the organic material treated by the superheated steam is 45% or less, It is set to 250 ° C or less.