JP2008055281A - Apparatus for supplying sludge to carbonizing furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a stable operation of a carbonizing furnace by properly supplying dried sludge to the carbonizing furnace even if the moisture content of the dried sludge changes. <P>SOLUTION: A quantitative feeder 21 for quantitatively supplying dehydrated sludge WS1 to a sludge drying furnace 3 is installed, and an intermediate hopper 5 airtightly connected to the carbonizing furnace 7 is installed between the sludge drying furnace 3 and the carbonizing furnace 7. A load cell 51 for detecting the weight of dried sludge WS2 supplied from the sludge drying furnace 3 to be stored in the intermediate hopper 5 is installed in the intermediate hopper 5, and a screw conveyor 52 for supplying the dried sludge in the intermediate hopper 5 to the carbonizing furnace 7 is installed on the outlet side of the intermediate hopper 5. A controller 6 for controlling the feeding amount of the screw conveyor 52 so that the weight of the detected sludge is always constant is installed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sludge supply apparatus for a carbonization furnace, and relates to a sludge supply apparatus that enables stable operation of the carbonization furnace.

  Sludge produced by sewage treatment is converted into dried sludge with a moisture content of about 40% in a sludge drying furnace, and then pyrolyzed in a low-oxygen state in a carbonization furnace to be reused as carbides with residual organic combustible components. ing. Usually, between the said sludge drying furnace and the carbonization furnace, the relay hopper which connected airtightly to the carbonization furnace used as the negative pressure and attached the cutting device is provided. In this relay hopper, a predetermined amount or more of dry sludge is stored to prevent air from entering the carbonization furnace having a negative pressure and changing the temperature in the carbonization furnace. Moreover, the capacity of the relay hopper is such that the dried sludge supplied from the sludge drying furnace can be stored for one hour or more, and the dried sludge supplied from the sludge drying furnace when the carbonization furnace is stopped due to trouble or the like. Can be temporarily stored. Then, a dry sludge having a predetermined weight is always supplied to the carbonization furnace by the cutting device. However, since the moisture content of the dried sludge from the sludge drying furnace is not constant and varies within a certain range, the weight of the dried sludge per unit time actually supplied to the carbonization furnace even when the screw conveyor is operated at a constant rotation (Cut amount) varies depending on the moisture content of the dried sludge.

That is, when the moisture content of the dried sludge increases, the bulk specific gravity decreases, so that the cut-out amount by the constant volume screw conveyor decreases. On the other hand, when the water content decreases, the bulk specific gravity increases and the cut-out amount increases. Therefore, for example, in Patent Document 1, the load change in the relay hopper upstream of the screw conveyor corresponding to the cutting amount is detected by the load cell, and when the cutting amount becomes small, the drying condition in the sludge drying furnace is increased. Sludge supply that reduces the moisture content of the dried sludge and increases the moisture content of the dried sludge by decreasing the sludge drying conditions when the amount of the cut is increased, so that the amount of the dried sludge is constantly controlled. A method has been proposed.
JP 2006-55743 A

   However, in the above conventional sludge supply method, even if the drying conditions of the sludge drying furnace are changed, the moisture content of the dried sludge does not quickly return to the desired value. There is.

  Therefore, the present invention solves such a problem, and even if the moisture content of the dried sludge varies, the dried sludge can be properly supplied to the carbonizing furnace, thereby realizing stable operation of the carbonizing furnace. It aims at providing the sludge supply apparatus to a carbonization furnace.

  The inventors have found that the stable operation of the carbonization furnace can be achieved by always keeping the solid content in the dried sludge supplied thereto constant. The present invention has been made on the basis of such knowledge, and provided with a quantitative supply device (21) for quantitatively supplying dewatered sludge (WS1) to the sludge drying furnace (3), and the sludge drying furnace (3), A relay hopper (5) airtightly connected to the carbonization furnace (7) is provided between the carbonization furnaces (7), and the relay hopper (5) is supplied from the sludge drying furnace (3) and is connected to the relay hopper (5). (5) A weight detector (51) for detecting the weight of the dried sludge (WS2) stored therein is provided, and the dried sludge (WS2) in the relay hopper (5) is provided at the outlet side of the relay hopper (5). ) Is supplied to the carbonization furnace (7), and a control device (6) for controlling the cutting amount of the cutting device (52) so that the detected sludge weight is always constant. Is provided.

  In the present invention, a fixed volume of dewatered sludge is supplied to the sludge drying furnace per unit time by a fixed supply device. Sludge consists of solids and moisture, and dehydrated sludge has a constant moisture content, so that a constant weight of solids per unit time is supplied to the sludge drying furnace. Since only moisture is evaporated in the sludge drying furnace, the solid content contained in the dried sludge per unit time discharged from the sludge drying furnace is always constant even if the moisture content fluctuates. Therefore, if the amount of dry sludge (weight) supplied to the relay hopper is cut out by the cutting device and supplied to the carbonization furnace, the solid content in the dry sludge supplied to the carbonization furnace is always a constant amount per unit time. Stable operation of the carbonization furnace is realized.

  In addition, the code | symbol in the said parenthesis shows the correspondence with the specific means as described in embodiment mentioned later.

  As described above, according to the sludge supply device to the carbonization furnace of the present invention, even if the moisture content of the dry sludge varies, the dry sludge can be properly supplied to the carbonization furnace, and the stable operation of the carbonization furnace can be achieved. Can be realized.

  FIG. 1 shows a system diagram of a sludge carbonization facility to which the method of the present invention is applied. In FIG. 1, a dewatered sludge WS1 dehydrated to a moisture content of about 80% is charged into a receiving hopper 1. The dewatered sludge WS1 is supplied from the receiving hopper 1 to the fixed supply device 21 by the conveyors 11 and 12, and is supplied to the sludge drying furnace 3 through this. In the sludge drying furnace 3, it is heated by the hot air supplied from the hot air furnace 4, and the dewatered sludge WS1 becomes a dry sludge WS2 having a moisture content of 35% to 45%. The dried sludge WS2 is conveyed to the relay hopper 5 by the conveyors 31 and 32 and supplied thereto. The relay hopper 5 is provided with a weight detector 51 such as a load cell, and the detection signal 51 a is input to the controller 6. The dried sludge WS2 in the relay hopper 5 is cut out by a constant displacement screw conveyor 52 provided on the outlet side and supplied into the carbonization furnace 7. The sludge CS carbonized and carbonized while passing through the retort of the carbonization furnace 7 is supplied to the storage hopper 73 on the outlet side by the conveyors 71 and 72 through the cooler 71. In order to prevent the outside air from entering the carbonization furnace 7 having a negative pressure, the inlet side of the carbonization furnace 7 and the outlet side of the relay hopper 5 provided with the screw conveyor 52 are actually connected in an airtight manner. Has been.

  Here, in this embodiment, the rotation speed of the screw conveyor 52 is controlled by the output signal 6 a of the controller 6. That is, the controller 6 knows the storage amount (weight) of the dried sludge WS2 in the relay hopper 5 from the detection signal 51a from the weight detector 51, and the rotation speed of the screw conveyor 52 so that the storage amount becomes a constant value, that is, Control the amount of clipping. As a result, the dried sludge WS2 in the relay hopper 5 is cut out and discharged by the amount supplied (weight).

  By the way, the dewatered sludge WS1 having a substantially constant water content is supplied to the sludge drying furnace 3 at a constant capacity per unit time by a constant supply device 21 such as a Mono pump. The sludge is composed of solids and moisture, and the dehydrated sludge WS1 has a constant water content, so that a constant weight of solids per unit time is supplied to the sludge drying furnace 3.

  Since only moisture is evaporated in the sludge drying furnace 3, even if the moisture content fluctuates from 35% to 45%, the solid content contained in the dried sludge WS2 per unit time discharged from the sludge drying furnace 3 is always constant. It is constant. Therefore, if the amount of dry sludge supplied to the relay hopper 5 (weight) is cut out by the screw conveyor 52 and supplied to the carbonization furnace 7, the solid content in the dry sludge WS2 supplied into the carbonization furnace 7 is a unit. The amount is always constant per hour, and the carbonization process is performed well.

It is a systematic diagram of the sludge supply apparatus which shows one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 ... Fixed quantity supply apparatus, 3 ... Sludge drying furnace, 5 ... Relay hopper, 51 ... Load cell (weight detector), 52 ... Screw conveyor (cutting device), 6 ... Controller (control apparatus), 7 ... Carbonization furnace, WS2 ... Dry sludge, WS1 ... dehydrated sludge.

Claims (1)

A fixed amount supply device for supplying dehydrated sludge to the sludge drying furnace is provided, and a relay hopper that is airtightly connected to the carbonization furnace is provided between the sludge drying furnace and the carbonization furnace. A weight detector for detecting the weight of the dried sludge supplied from the sludge drying furnace and stored in the relay hopper is provided, and the dried sludge in the relay hopper is supplied to the carbonization furnace on the outlet side of the relay hopper. A sludge supply apparatus for a carbonization furnace, characterized in that a cut-out apparatus for supply is provided, and a control device for controlling a cut-out amount of the cut-out apparatus so that the detected sludge weight is always constant.

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