JP3605262B2 - Heat recovery system from sludge exhaust steam - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a system for recovering heat from sludge exhaust steam, and more particularly to a system for recovering heat from exhaust steam obtained when drying waste such as sewage sludge.
[0002]
[Problems to be solved by the invention]
FIG. 3 shows a conventional drying process of waste such as sewage sludge and a flow chart of exhaust steam.
In the figure, reference numeral 101 denotes a dryer, 102 denotes a jet condenser, and 103 denotes an incinerator. Sludge dried in the dryer 101 is fed into the incinerator 103 together with fuel and air as dry sludge to perform predetermined incineration.
On the other hand, the exhaust steam generated during the drying of the sewage sludge generated in the dryer 101 contains dust and fat, etc., and thus is not particularly subjected to heat recovery. After being washed by contact and removing dust and fat, etc., it was placed in an incinerator 103 for treatment.
[0003]
Therefore, in the above-mentioned prior art, despite the heat energy by the exhaust steam drying heat generated at the time of sewage sludge drying, the heat is removed by washing with the cooling water, and the hot waste water thus removed is also heated. Because it is a low-temperature wastewater that is difficult to use as a heat source, it has not been effectively used as thermal energy.
In view of the drawbacks of the related art, an object of the present invention is to provide a system capable of performing heat recovery by effectively utilizing heat energy possessed by exhaust steam obtained when drying waste such as sewage sludge. And
[0004]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a separator for separating and removing medium dust in exhaust steam discharged from a dryer for drying sludge, an exhaust steam from which the medium dust has been removed is introduced, and an outlet temperature thereof is set to a predetermined value. A heat exchanger for recovering heat while maintaining the temperature or higher, wherein the separator is a cyclone separator that forms a swirling flow by injecting steam for generating a swirling flow different from the exhaust steam into the separator. characterized in that the configuration was.
In this case, the exchange as described in claim 2 of the injection quantity of steam of the swirling flow for generating as described that control by detecting the outlet temperature of the heat exchanger C., further claim 3 It is preferable that the recovered heat in the vessel is used as a heat source of the dryer.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be illustratively described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only.
FIG. 1 is an overall view showing a flow diagram of exhaust steam of a heat recovery system according to an embodiment of the present invention discharged from a dryer for waste such as sewage sludge, and FIG. The flow (swirling flow) of the exhaust steam is shown by (A).
In FIG. 1, a heat recovery system from exhaust steam 14 of a dryer 1 performs heat recovery from a cyclone 2 that removes dust 21 such as powdery sludge and exhaust steam 14A while preventing scaling of fat. It is composed of a heat exchanger 3.
[0006]
The cyclone 2 into which the exhaust steam 14 from the dryer 1 is introduced is configured to be able to form a stronger swirling flow in the cyclone 2 by injecting the steam 11 through the steam valve 4. By increasing the centrifugal force by swirling together with the swirling flow of the steam 11, it is possible to remove the medium dust 21 (powder sludge or the like) which is difficult to collect.
Accordingly, the dust 21 such as powder sludge is removed in the cyclone 2, and the exhaust steam 14 </ b> A containing fat is introduced into the heat exchanger 3.
The heat exchanger 3 is provided with a controller 5 having a built-in temperature sensor at the outlet side of the exhaust steam 14B. The controller 5 controls the steam valve 4 on the cyclone 2 side based on a signal 15 from the controller 5 and performs heat exchange. The heat source 12 for exchanging heat with the exhaust steam 14A in the heat exchanger 3 while circulating the heat source 12 for drying the sludge is circulated in the dryer 1, the dryer 3, the heat exchanger 3, and the heat exchanger 3. It is configured to be repeatedly introduced and sludge dried.
That is, since the exhaust steam 14A introduced into the heat exchanger 3 is always mixed with the swirl flow generating steam 11 in the cyclone 2, the temperature is high and the heat source fluid 12 for sludge drying can be sufficiently heated. I can do it.
[0007]
In the heat exchanger 3, the exhaust steam 14A / B is deprived of heat by heat exchange with the heat source fluid 12 for drying sludge. When the exhaust steam 14A / B falls to, for example, 60 ° C. or less, the exhaust steam 14A / B removes fat. Because of the inclusion, scaling due to the condensation of fat occurs in the heat exchange pipe and the like. However, if the mixing ratio of the steam 11 for generating the swirl flow of the exhaust steam 14 in the cyclone 2 is increased, the heat exchanger 3 , The temperature of the exhaust steam 14A introduced into the air can be increased.
For example, the temperature of the exhaust steam 14 at the time of introduction into the cyclone 2 can be 90 to 110 ° C., and the temperature of the exhaust steam 14A discharged from the cyclone 2 and introduced into the heat exchanger 3 can be increased to about 150 ° C.
Therefore, in the present embodiment, the outlet temperature of the heat exchanger 3 prevents the fat from being condensed based on a signal 15 from the controller 5 that generates a control signal while detecting the temperature of the outlet side of the exhaust steam 14B. The degree of opening of the steam valve 4 is controlled so as to keep the obtained temperature at 60 ° C. or higher, thereby preventing fat scaling in the heat exchanger 3.
[0008]
Further, in the present embodiment, by injecting steam into the cyclone 2 from the steam valve 4, the amount of exhaust steam 14 is increased together with the generation of the swirling flow, the concentration of dust and fat is reduced, and the scaling prevention effect is obtained. And the efficiency of collecting dust in the cyclone 2 can be improved.
Therefore, according to the present embodiment, it is possible to recover heat from dirty exhaust steam containing dust and fat, which has not been conventionally performed.
[0009]
【The invention's effect】
According to the first and second aspects of the present invention as described above, a separator, preferably a cyclone, which separates and removes the dust in the exhaust steam discharged from the dryer is used, and the steam is injected into the cyclone. Thus, by forming a stronger swirling flow and increasing the centrifugal force, it is possible to effectively remove medium dust (powder sludge and the like) which is difficult to collect.
Further, the exhaust steam from which the dust has been removed is introduced, and a heat exchanger for recovering heat while maintaining the outlet temperature at or above a predetermined temperature is provided, thereby preventing scaling due to fat condensation and preventing a long term. Heat can be stably recovered over a long period of time.
Further, by using the heat recovered by the exchanger as a heat source of the dryer, an independent heat source of the dryer is not required.
And so on.
[Brief description of the drawings]
FIG. 1 is an overall view showing a flow chart of exhaust steam of a heat recovery system according to an embodiment of the present invention discharged from a dryer for waste such as sewage sludge.
FIG. 2 is a diagram showing a main part configuration (B) of FIG. 1 and a flow (a swirling flow) (A) of exhaust steam in a cyclone.
FIG. 3 is a flow chart of a conventional drying process of waste such as sewage sludge and exhaust steam.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Dryer 2 Cyclone 3 Heat exchanger 4 Steam valve 5 Controller

Claims (3)

A separator for separating and removing the dust in the exhaust steam discharged from the dryer for drying the sludge, and the exhaust steam from which the dust is removed are introduced, and the outlet temperature is maintained at a predetermined temperature or higher to recover heat. Characterized in that the separator comprises a cyclone separator that forms a swirling flow by injecting steam for generating a swirling flow different from the exhaust steam into the separator. Heat recovery system from exhaust steam. A separator for separating and removing the dust in the exhaust steam discharged from the dryer for drying the sludge, and the exhaust steam from which the dust is removed are introduced, and the outlet temperature is maintained at a predetermined temperature or higher to recover heat. provided with a heat exchanger which, the separator, in its interior, constituted by a cyclone separator to form a swirling flow by jetting exhaust steam and different, steam swirling flow for generation of revolving circumfluence heat recovery system of the injection quantity of steam for generating from sludge discharged steam you characterized and Turkey be controlled by detecting the outlet temperature of the heat exchanger. The system for recovering heat from sludge exhaust steam according to claim 1 or 2, wherein the recovered heat in the exchanger serves as a heat source for the dryer.

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