JP2005000896A - Method and apparatus for pressure feeding of dewatered sludge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce pressure loss in pressure feeding a dewatered sludge without requiring a lubricant. <P>SOLUTION: One end part of a tapered pipe 4 whose diameter in the intermediate part is smaller than that in the both ends by the predetermined dimensions is detachably connected to the downstream side of a discharge pipe 2 of a pressure feeding pump 1 for sludge. The other end part of the tapered pipe 4 is detachably connected to the upstream side end part of a duct 3 for dewatered sludge. A dewatered sludge 6 is discharged by the operation of the pressure feeding pump 1 for sludge through the discharge pipe 2. The dewatered sludge 6 is compressed by being passed through a tapered throttle part 4a of the tapered pipe 4, thus making the moisture content contained inside the dewatered sludge 6 to come on the surface of the dewatered sludge 6. The water came on the surface of the dewatered sludge 6 is mediated between the surface and the inner wall surface of the duct 3 for dewatered sludge, thereby smoothly performing pressure feeding of the dewatered sludge 6 inside the duct 3 for dewatered sludge. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dewatered sludge pumping method and apparatus for use in pumping dewatered sludge to a destination such as an incinerator using a sludge pump in a sewage treatment facility or the like.
[0002]
[Prior art]
The sewage sludge generated at the sewage treatment plant is treated with activated sludge from organic matter contained in the sewage and fixed in the form of microorganisms, and then these microorganisms, their dead bodies, excrement, and other fine suspended particles are inorganic. It is agglomerated and precipitated by a required aggregating agent such as an aggregating agent or a polymer aggregating agent. Therefore, since the sewage sludge contains a large amount of organic matter, it is generally concentrated using gravity separation, flotation separation, etc., and then pressurized dehydration equipment such as a vacuum dehydrator or a belt press, or a centrifugal separator. In many cases, the moisture content is reduced to about 80 to 65% using a dehydrating device such as a separator to form a cake-like dewatered sludge (dehydrated cake), and then sent to an incinerator for incineration.
[0003]
Thus, when dehydrated sludge is sent to an incinerator for incineration, the dehydrated sludge recovered from the dehydrator has a high viscosity, so that it is pumped through the dehydrated sludge transport pipe using a pump. I have to.
[0004]
As a pump used for the pumping of this kind of dewatered sludge, for example, the pistons in the two pumping cylinders connected to the lower part of the sludge receiving hopper for feeding the dewatered sludge are alternately switched by two corresponding main hydraulic cylinders. The suction / discharge operation can be performed alternately by moving forward and backward, and a swing pipe as a suction / discharge valve is swingably provided in the sludge receiving hopper, and one end communicates with each of the pressure feeding cylinders alternately. In addition, the other end is connected to a discharge pipe serving as a sludge outlet, and the dewatering in the sludge receiving hopper is performed by switching the oscillating pipe in synchronization with the suction and discharge operation of each of the pressure feeding cylinders. Reciprocating double-piston type pistons that allow sludge to be alternately sucked into the above-mentioned cylinders for pumping, and then pumped down the dewatered sludge transport pipe through the swing pipe and discharge pipe. Feed pump is used (e.g., see Patent Document 1).
[0005]
By the way, the viscosity of the dewatered sludge changes when the water content varies, and particularly when the water content decreases, the viscosity increases. Therefore, there is a bent portion in the middle of the dewatered sludge transport pipe connected to the downstream side of the sludge pump. In such a case, there is a concern that the resistance at the time of circulation of the dewatered sludge increases at the bent portion, and therefore, the pressure loss at the time of pressure feeding of the dehydrated sludge increases.
[0006]
In order to prevent such pressure loss during dewatered sludge pumping, it is considered that the dewatered sludge can be smoothly distributed in the sludge pumping line. As a method for smoothly circulating such dewatered sludge in the pressure feed line, for example, medium oil is previously applied to the dewatered sludge received in the sludge receiving hopper connected to the upstream side of the pressure feed pump. Some have been added. That is, medium oil is added to the dewatered sludge, and when the dehydrated sludge pumped by the pressure pump passes through the transport line, the added medium oil is applied to the inner wall surface of the transport line. Then, the medium oil applied to the inner wall surface of the transfer line is allowed to act as lubricating oil for the dehydrated sludge that circulates in the transfer line, thereby preventing clogged dehydrated sludge having the above-mentioned viscosity and smoothing the sludge transfer. Has been proposed (see, for example, Patent Document 2).
[0007]
In addition, as a technique for preventing adhesion and lamination of the shooter serving as a sludge transfer path for the heated dehydrated sludge having adhesiveness, a plurality of nozzles for jetting lubricating oil to the upper inner wall of the shooter are provided. And a lubricant film is formed over the entire inner wall surface of the shooter by spraying the lubricant oil from the nozzles along the inner wall of the shooter. It has also been proposed to prevent the sticking and allow it to pass smoothly (see, for example, Patent Document 3).
[0008]
Therefore, as a measure for preventing an increase in pressure loss during dewatered sludge pumping even when the moisture content of the dewatered sludge decreases and the viscosity increases, for example, a bent portion of a sludge pumping pipeline A lubricant injection device is connected to a position immediately before the injection of a lubricant such as lubricating oil, so that the space between the inner wall surface at the bent portion of the sludge pressure feeding line and the surface of the dewatered sludge flowing inside the sludge It is conceivable to suppress the increase in the pressure loss in the pipe by interposing the above-mentioned lubricant.
[0009]
[Patent Document 1]
Japanese Patent Laid-Open No. 2003-63662 [Patent Document 2]
JP-A-10-85794 [Patent Document 3]
Japanese Patent Laid-Open No. 11-165193
[Problems to be solved by the invention]
However, in order to prevent pressure loss at the time of dewatered sludge pumping, in the method of injecting a lubricant such as lubricating oil as shown in Patent Document 2 and Patent Document 3 above, the running cost is low because the lubricant is consumed. In addition to the problem that it is bulky, there is also a problem that the equipment becomes complicated and the equipment cost increases because it is necessary to provide a lubricant injection device.
[0011]
Therefore, the present invention is a case where the water content of the dewatered sludge is reduced and the viscosity of the dewatered sludge is increased. It is an object of the present invention to provide a dewatered sludge pressure-feeding method and apparatus that can smoothly distribute sludge and reduce pressure loss.
[0012]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention allows dehydrated sludge discharged from a sludge pump to be pumped to a destination through a pumping pipeline, and compresses the sludge in the middle of pumping to exude moisture inside the sludge. , A method of pumping dewatered sludge by pumping dehydrated sludge so as to generate water between the sludge surface and the pipe wall, and a midway position of a pumping line for pumping dewatered sludge discharged from the sludge pump. A dewatered sludge having a configuration in which a throttle is provided that is reduced in diameter from the upstream side, and the dewatered sludge is compressed by the throttle so that moisture contained therein is exuded to the surface of the dehydrated sludge and pumped. A pumping device is used.
[0013]
When the dewatered sludge is pumped downstream through the pumping pipeline by operating the sludge pump, the dewatered sludge is compressed when passing through the throttle in the middle of the pumping pipeline. By this compression, moisture contained in the dehydrated sludge is oozed out on the surface of the dehydrated sludge. Even if the dewatered sludge is reduced in the compressed state due to the dewatered sludge moving to the downstream side of the throttle, the water that has been leached is present on the surface of the dewatered sludge. In the pressure feed line, water is generated between the inner wall surface of the pressure feed line and the surface of the dewatered sludge. For this reason, the distribution of the dewatered sludge in the pressure-feed pipeline is smoothly performed.
[0014]
In addition, by adopting a configuration in which a taper pipe formed with a tapered throttle part as a throttle is detachably attached between a discharge pipe of a sludge pressure feed pump as a pressure feed line and a dewatered sludge transport pipe, If a plurality of taper pipes with different diameter reduction ratios are prepared, the moisture contained in the dewatered sludge is changed on the surface as the viscosity changes due to the change in the moisture content of the dewatered sludge. Even if the compression rate of the dewatered sludge required for leaching changes, the water content can be changed by appropriately selecting and replacing a taper tube having a reduced diameter corresponding to the required dewatered sludge compression rate. Therefore, it is possible to easily prevent pressure loss at the time of pumping dewatered sludge having different sizes.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
FIGS. 1 (a) and 1 (b) show an outline of an embodiment of a dewatered sludge pressure feeding method and apparatus according to the present invention. The discharge pipe 2 and the pressure pipe are connected to the discharge side of the sludge pressure feed pump 1 as a pressure feed line. In the configuration provided with the dewatered sludge transport pipe 3 that is connected to the discharge pipe 2 and pumps the dehydrated sludge, as an example, the connecting portion between the discharge pipe 2 and the dewatered sludge transport pipe 3 is provided with both ends as a throttle. The diameter is the same as the diameter of the discharge pipe 2 and the dewatered sludge transport pipe 3 of the sludge pump 1 and the middle part has a diameter d smaller than the diameter D of both ends, and is directed from both ends toward the middle part. One end of the taper tube 4 is detachably connected to the downstream end of the discharge pipe 2 through a taper tube 4 having a shape with a tapered throttle portion 4a that smoothly reduces the diameter. The other end of the tube can be attached to and detached from the upstream end of the dewatered sludge transport pipe 3 To continue.
[0017]
The connection between the discharge pipe 2 of the sludge pump 1 and one end of the taper pipe 4 and the connection between the other end of the taper pipe 4 and the upstream end of the dewatered sludge transport pipe 3 are, for example, connected. Flange portions 2a, 4b and 3a, 4b are respectively formed at the power ends, and the discharge pipe 2, taper pipe 4, taper pipe 4, and flange portions 2a, 4b of the dewatered sludge transport pipe 3 are in contact with each other. And 3a and 4b may be detachably connected using bolts and nuts 5.
[0018]
The inclination angle of the tapered throttle portion 4a formed from both ends of the taper tube 4 toward the intermediate portion is such that the dewatered sludge 6 discharged from the discharge tube 2 of the sludge pressure pump 1 at a required pressure is used as the taper tube. 4, when the dewatered sludge 6 is compressed toward the intermediate portion along the tapered throttle portion 4 a that is reduced in diameter from the upstream end, the water contained in the dewatered sludge 6 is reduced. The inclination angle is set so that it can be raised on the surface of the dewatered sludge 6. Further, after the diameter is reduced so as to be squeezed toward the intermediate portion, the diameter is increased to the other end side which is the downstream side, and the dewatered sludge 6 is expanded and sent to the downstream side. Therefore, the length dimension of the taper pipe 4 and the reduction ratio of the diameter d of the middle part with respect to the diameter D of both ends are determined by the discharge pressure of the sludge pump 1 and the diameter of the discharge pipe 2 of the sludge pump 1. What is necessary is just to determine suitably based on the inclination-angle requested | required of the said taper-shaped aperture | diaphragm | squeeze part 4a.
[0019]
A sludge receiving hopper 7 is provided on the suction side of the sludge pump 1.
[0020]
When the dewatered sludge 6 is pumped by the dewatered sludge pressure feeding method and apparatus of the present invention having the above-described configuration, the dewatered sludge 6 introduced into the sludge receiving hopper 7 is transferred to the pump 1 by the operation of the sludge pump 1. It is made to discharge through the discharge pipe 2 of this. When the dewatered sludge 6 discharged through the discharge pipe 2 is fed into the taper pipe 4 and passed from the one end side to the other end side, the dewatered sludge 6 is moved from the upstream end of the taper pipe 4 to the intermediate portion. The taper is gradually compressed by the tapered throttle portion 4a that is reduced in diameter.
[0021]
Here, when examining the binding state of water to the agglomerated sludge, as shown in FIG. 2, free water 8 and sludge particles existing around the agglomerates of the sludge particles 6a are included in the water bound to the sludge. The pore water 9 taken in the gap (gap) formed by surrounding the sludge particles 6a when the 6a agglomerates, and the capillaries formed between the sludge particles 6a adjacent to each other by agglomeration Capillary binding water 10 taken into the gap, internal retained water 11 taken into the individual sludge particles 6a, surface adhering water 12 bound to the surface of the sludge particles 6a, sludge particles 6a, etc. There is water of crystallization (not shown) that is contained in crystals such as salts. These waters vary in the degree of difficulty in separating (dehydrating) from sludge depending on their binding state, and include free water 8, pore water 9, capillary-bonded water 10, surface adhering water 12, internal reserve water 11, and crystal water. In this order, dehydration becomes more difficult, and in the mechanical dehydration, only a part of the free water 8, the interstitial water 9, and the capillary combined water 10 is dehydrated. For this reason, a considerable amount of water remains inside the dewatered sludge 6. When the dewatered sludge 6 is compressed, a part of the water remaining in the dewatered sludge 6 is removed from the dewatered sludge 6. It can be raised (exuded) on the surface. It should be noted that when the dewatered sludge 6 is compressed, the water that once floated on the surface of the dewatered sludge 6 remains floating on the surface of the dewatered sludge 6 even if the compression on the dewatered sludge 6 is eased thereafter. Become.
[0022]
In the present invention, the dewatered sludge 6 is compressed to take advantage of the property that the water inside floats to the surface, and the inside of the dewatered sludge transport pipe 3 is smoothly pumped by the raised water. .
[0023]
In the above, a part of the water contained in the dewatered sludge 6 in the process of the dewatered sludge 6 sent from the discharge pipe 2 to the taper pipe 4 being gradually compressed by the tapered throttle portion 4a. When exuded on the surface, the exuded water is generated between the surface of the dehydrated sludge 6 and the inner wall surface of the dehydrated sludge transport pipe 3. As a result, the dewatered sludge 6 is transferred from the taper pipe 4 into the dewatered sludge transport pipe 3 in a state of being wrapped with water oozed from the inside. At this time, even if the diameter is expanded at the downstream end of the taper pipe 4, the water that has oozed out on the surface of the dewatered sludge 6 is retained along the inner wall surface of the dewatered sludge transport pipe 3. Thus, the dewatered sludge transport pipe 3 can be circulated.
[0024]
In this way, when the dewatered sludge 6 is pumped, water can be generated between the surface of the dewatered sludge 6 and the inner wall surface of the dewatered sludge transport pipe 3. It is possible to prevent the dewatered sludge 6 to be adhered to the inner wall surface of the dewatered sludge transport pipe 3 in advance. For this reason, even when the water content of the dewatered sludge 6 is reduced to about 50% and the viscosity becomes large, the dewatered sludge 6 can be smoothly pumped. The pressure loss in can be reduced. Moreover, the water generated between the surface of the dewatered sludge 6 and the inner wall surface of the dewatered sludge transport pipe 3 during the pumping of the dewatered sludge 6 causes the dewatered sludge 6 discharged from the sludge pressure pump 1 to flow through the taper tube 4. Since it is generated by compressing with the tapered throttle portion 4a, supply from the outside is not necessary. Accordingly, it is possible to reduce the running cost and the equipment cost as compared with the conventional case where a lubricant such as lubricating oil is used to reduce the pressure loss at the time of dewatered sludge pumping.
[0025]
Further, since the taper pipe 4 is detachably attached between the discharge pipe 2 of the sludge pump 1 and the dewatered sludge transport pipe 3, the compression rate is reduced as the moisture content of the dewatered sludge 6 changes. In the case where the internal moisture is always made to float on the surface by changing, a plurality of taper tubes 4 having different diameter reduction ratios of the diameter d of the middle part with respect to the diameter D of both ends are prepared. In this way, the taper tube 4 having a diameter reduction rate that can correspond to the compression rate required for exuding the moisture inside the dewatered sludge 6 according to the water content of the dewatered sludge 6 to be pumped is appropriately selected. It can be selected and replaced, and it is possible to easily prevent pressure loss during the pressure-feeding of the dewatered sludge 6 having different moisture contents.
[0026]
In addition, this invention is not limited only to the said embodiment, The taper pipe | tube 4 can be easily replaced | exchanged for what has the diameter reduction ratio of the intermediate part diameter d with respect to both-ends diameter D as needed easily. Although it is desirable to make it separate from the sludge pressure pump 1 and the dewatered sludge transport pipe 3, the tapered sludge 6 is provided as a throttle in the middle of the discharge pipe 2 in the sludge pressure pump 1 to compress the dewatered sludge 6. Alternatively, a tapered throttle portion may be provided at the upstream portion of the dewatered sludge transport pipe 3 as a throttle. Moreover, although the said taper pipe | tube 4 was shown as what was equipped with the taper-shaped aperture | diaphragm | squeeze part 4a which has the same inclination from both ends toward an intermediate part, the inclination angle from the one end side used as an upstream to an intermediate part, It may have a shape in which the inclination angle from the other end portion on the downstream side to the intermediate portion is different, or may have a shape in which the inclination angle changes in the middle of the tapered throttle portion 4a. Furthermore, the sludge pump 1 may be of a type other than the reciprocating double piston type, and other various modifications may be made without departing from the scope of the present invention.
[0027]
【The invention's effect】
As described above, according to the present invention, the following excellent effects are exhibited.
(1) The dehydrated sludge discharged from the sludge pump and pumped to the destination through the pumping line is compressed in the middle of the pumping to exude moisture from the sludge surface. In order to reduce the diameter from the upstream side to the midway position of the dewatering sludge pumping method that pumps dehydrated sludge so that water is generated in between, and the dewatered sludge discharged from the sludge pump Since the dewatered sludge has a structure configured to compress the dehydrated sludge with the squeeze and exude the moisture contained therein to the surface of the dehydrated sludge and pump it, During pumping, dewatered sludge can be circulated in a state where water is generated between the inner wall surface of the pumped pipe and the surface of the dewatered sludge in the pumped line downstream of the throttle. Water content of dewatered sludge Even if the rate decreases and the viscosity increases, the dewatered sludge can be pumped smoothly, and the pressure loss during the dewatered sludge pumping can be reduced.
(2) The water generated between the surface of the dewatered sludge and the inner wall surface of the pressure-feed pipeline during the pumping of the dewatered sludge is compressed from the inside of the dewatered sludge by compressing the dewatered sludge by passing through a throttle. Can be exuded and supplied. For this reason, since supply of water from the outside is unnecessary, the running cost and the equipment cost are reduced as compared with the case of using a lubricant such as lubricating oil to reduce the pressure loss at the time of dewatered sludge pumping. It becomes possible.
(3) By adopting a configuration in which the tapered pipe formed with the tapered throttle section as the throttle is detachably attached between the discharge pipe of the sludge pressure feed pump as the pressure feed pipe and the dewatered sludge transport pipe, If a plurality of tapered pipes with different diameter reduction ratios are prepared, the moisture contained in the dewatered sludge is removed from the surface as the viscosity changes due to the change in the moisture content of the dewatered sludge. Even if the compression rate of the dewatered sludge required for leaching is changed, the taper tube having a diameter reduction rate corresponding to the required dewatered sludge compression rate is appropriately selected and replaced, so that It is possible to easily prevent pressure loss during the pumping of dewatered sludge having different rates.
[Brief description of the drawings]
FIG. 1 shows an embodiment of a dewatered sludge pumping method and apparatus according to the present invention. FIG. 1 (a) is a schematic side view, and FIG.
FIG. 2 is a diagram schematically showing a combined state of sludge and water.
[Explanation of symbols]
1 Sludge pressure pump 2 Discharge pipe (pressure line)
3 Dewatered sludge transport pipe (pressure feed line)
4 Taper tube (diaphragm)
4a Tapered diaphragm (diaphragm)
6 Dewatered sludge

Claims (3)

The dehydrated sludge discharged from the sludge pump and pumped to the destination through the pressure pipe is compressed in the middle of the pumping so that the moisture inside the sludge exudes and the water between the sludge surface and the pipe wall A method for pumping dehydrated sludge, characterized in that dehydrated sludge is pumped in such a manner as to generate water. A throttle that is reduced in diameter from the upstream side is provided in the middle of the pumping pipeline for pumping the dewatered sludge discharged from the sludge pump, and the dewatered sludge is compressed by the throttle to reduce the moisture contained inside. A dewatered sludge pumping device characterized in that the dewatered sludge is exuded on the surface and pumped. 3. The dewatered sludge pressure feed according to claim 2, wherein a taper pipe formed with a taper-shaped restrictor as a restrictor is detachably attached between a discharge pipe of a sludge pressure feed pump as a pressure feed line and a dehydrated sludge transport pipe. apparatus.

Images