JPS5814280B2 - Sludge freezing treatment equipment - Google Patents

Description

Detailed Description of the Invention This invention supplies a predetermined amount of sludge into an inner tube, then freezes it with cold brine flowing inside the outer tube, heats and thaws the frozen sludge, and converts it into water and solids. This invention relates to a so-called "batch-type sludge freezing treatment device" that separates sludge and sends it to a dehydrator. In particular, this invention relates to a heat exchanger between sludge and warm or cold brine that freezes or heats and thaws this sludge. .

Figures 1 and 2 show this kind of cylindrical "batch type sludge freezing treatment equipment", in which 1 is a cylindrical type in which a predetermined amount of sludge 3 supplied from a feed pipe 2 is transferred from one end to the other. The inner pipe 4 for circulation is an outer pipe surrounding the inner pipe 1 with a gap G,
This outer pipe 4 is provided with a brine supply pipe 5 and a brine discharge pipe 6 for flowing hot or cold prine from one end of the gap G to the other end.

Reference numeral 7 designates spiral heat exchange fins having an even pitch and housed in the gap G in contact with the outer circumferential surface of the inner tube 1 and the inner circumferential surface of the outer tube 4.

Since the conventional sludge freezing treatment apparatus is configured as described above, a predetermined amount of sludge 3 is supplied from the feed pipe 2 into the inner pipe 1 as shown in FIG. When cold brine is fed into the gap G, the cold brine circulates in the gap G by the spiral heat exchange fins 1 and freezes the sludge 3 via the fins 7 and the inner pipe 1. let

Therefore, the ten heat exchange fins 7 are formed in a spiral shape to improve the heat exchange efficiency between the cold brine and the sludge, and to equalize the heat exchange efficiency on the inlet and outlet sides of the cold brine. Furthermore, the sludge 3 supplied into the inner pipe 1 has a moisture content and temperature difference depending on its position, so if the sludge is uniformly cooled over the entire length within the inner pipe 1, the sludge As freezing progresses, as shown in FIG. 2, unfrozen sludge 3A is often generated which is partially enclosed in frozen sludge 3A in the center.

This is because the sludge in the inner tube 1 begins to be cooled simultaneously over its entire length, and when the unfrozen sludge 3A is interposed in the center of the frozen sludge 3 in this way, the volume expansion occurs when the unfrozen sludge 3A freezes. There is a risk that the inner tube 1 will be destroyed.

This invention was made with attention to this point, and it actively increases the difference in heat exchange efficiency between the inflow side and the outflow side of the cold brine in the outer tube 4 from one end of the inner tube 1 to the other side. The unfrozen sludge 3 mentioned above is
The present invention aims to provide a sludge freezing treatment device that prevents the occurrence of A.

That is, FIG. 3 shows one embodiment of the present invention, and since the same reference numerals and components are the same as those of the conventional device (FIG. 1) described above, the explanation thereof will be omitted.

8 is a spiral heat exchange fin housed in the gap G in contact with the outer circumferential surface of the inner tube 1 and the inner circumferential surface of the outer tube 4;
The pitch of the heat exchange fins 8 is small on the sludge inflow side and gradually increases toward the outflow side.

That is, as shown in FIG. 3, from the pline supply pipe 5 side to the brine discharge pipe 6 side, the pitch P1<P2.
It is spirally wound so that <P3...Pn.

Therefore, the flow rate of the cold brine introduced from the brine supply pipe 5 and flowing through the gap G becomes slower toward the brine discharge pipe 6.

As the flow rate of the cold brine decreases, the heat exchange efficiency also decreases, so the freezing rate of the sludge in the inner pipe 1 is necessarily faster on the brine supply pipe 5 side and gradually becomes slower toward the brine discharge pipe 6.

Therefore, as shown in FIG. 4, the frozen sludge in the sludge freezing treatment apparatus of the present invention begins to freeze from the brine supply pipe 5 side, that is, from the sludge feed pipe 2 side, and gradually moves to the brine discharge pipe 6 side. Since freezing progresses in a tapered manner, unfrozen sludge 3
A is not contained in frozen sludge 3,
This has an excellent effect of preventing the inner tube 1 from being destroyed due to freeze expansion of the unfrozen sludge 3A.

In addition, the pinch of the heat exchange fin 8 is P1<P2<P3 as in the above-mentioned embodiment.
・The relationship is not limited to Pn, but the key is to increase the flow velocity on the brine supply pipe 5 side and slow the flow velocity on the brine discharge pipe 6 side, so that the sludge gradually freezes from the sludge supply pipe 2 side. Good to have.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional sludge freezing treatment device, Fig. 2 is an explanatory diagram of its freezing operation, Fig. 3 is a sectional view showing an embodiment of the present invention, and Fig. 4 is an explanatory diagram of its freezing operation. . In the drawings, 1 is an inner tube, G is a gap, 3 is frozen sludge, 3A is unfrozen sludge, 4 is an outer tube, and 8 is a heat exchange fin. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. An inner pipe through which sludge flows from one end to the other end, and an outer pipe surrounding the inner pipe through a gap, and through which hot or cold brine flows from one end of the gap to the other end. In a sludge freezing treatment apparatus comprising a pipe and a spiral heat exchange fin housed in the gap in contact with the outer pipe and the inner pipe, the pitch of the spiral heat exchange fin is A sludge freezing treatment apparatus characterized in that the sludge is made smaller on the sludge inflow side and gradually becomes larger toward the sludge outflow side.