JPH1085794A - Sludge treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a feed line from being clogged with viscous sludge by applying medium oil onto the inner wall surface of the line. SOLUTION: The sludge treatment system comprises a sludge receiving hopper A, a feed pump B, a preliminary treatment tank C, a cooker D, the internal pressure of which is reduced and in which heating oil is stored, a mist catcher E, and a condenser F. Furthermore, medium oil is added to sludge in the hopper A to provide a function of lubricating oil, when the sludge is sent, under pressure, to the tank C by the pump B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for treating sludge.

[0002]

2. Description of the Related Art Conventionally, sludge is treated by heating in a boiler, dewatering, pulverizing and discarding, or by heating and dehydrating in heated oil to use as fertilizer or building material. And so on.

[0003]

However, mere heating and dehydration of sludge causes a pollution problem, and complete dehydration is impossible, fuel economy is high, and it is not economical. It is necessary to smoothly transport the raw material into the above-mentioned cooker, and various problems occur. In particular, when the sludge is transported as the raw material, there is a drawback such that sludge clogging occurs in the transport line.

[0004]

According to the present invention, a sludge treatment system comprises a sludge receiving hopper, a pressure pump, a pretreatment tank, a cooker in which the inside is decompressed and contains heating oil, a mist catcher, and a condenser. A sludge treatment method characterized by adding a medium oil to the sludge in the sludge receiving hopper so as to fulfill the function of lubricating oil when the sludge is pumped to the pretreatment tank by the pump. Is what you do.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, first, sludge serving as a processing raw material is charged into a sludge receiving hopper.

[0006] At this time, the medium oil is added to the sludge, the amount of which is equal to or about one half of the weight of the raw sludge.

Next, the sludge is pumped together with the medium oil into the pretreatment tank by the pump.

[0008] At this time, the medium oil is applied to the inner wall surface of the pressure feed line so that the sludge can be transported smoothly, and the clogging of the viscous sludge can be prevented.

The sludge pumped to the pretreatment tank is stored in a cooker together with the medium oil. The storage in the cooker is performed by the negative pressure by the pressure reduction operation in the cooker. In the cooker, the internal pressure is reduced and the medium oil and the sludge are heated from the cooker jacket. As the medium oil is heated, the boiling point of water under reduced pressure decreases.
Then, the specific gravity between the heating oil and the water is replaced, and the water contained in the sludge tissue evaporates by the heating oil.

[0010] The evaporated water, ie the particles in the steam,
It is sieved with a mist catcher and only steam is sent to the condenser.

In the condenser, water vapor is condensed and liquefied, and is taken out as condensed water.

Further, the sludge heated in the cooker by the heated medium oil, that is, the heated oil, is taken out of the cooker into the cooker receiving tank together with the completion of the heat treatment under the reduced pressure condition.

[0013] The dewatered sludge taken out of the cooker receiving tank is conveyed to a centrifugal separator to be deoiled, and contains 6% or more of water.
A product of 20% powdery sludge raw material is produced. Since it contains a small amount of oil, it can be effectively used as a combustion aid or fertilizer in a cement plant or the like.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic view of a treatment system used in the sludge treatment method of the present invention, wherein A is a sludge receiving hopper, B is a pressure pump, C is a pretreatment tank, D
Is a cooker; E is a mist catcher; F is a condenser; G is a cooker receiving tank; The heating steam is sent to the rotary blade communication passage 3 and the jacket portion 4 of the cooker D to heat the inside of the cooker D. 5 is a return line for condensed water drained from the heated steam. Reference numeral 6 denotes a circulating water flow path for cooling and draining the steam sent to the condenser F. Reference numeral 7 denotes a flow path for taking out condensed water drained from below the condenser F. 8 is the condenser F
Vacuum pump to create a negative pressure for suction into Reference numeral 9 denotes a line for taking out the dried sludge from the cooker D and transferring it to the cooker receiving tank G. Reference numeral 10 denotes a vacuum suction hole provided in the cooker D.

The treatment system used in the embodiment of the present invention is configured as described above. Sludge is dewatered in advance to a water content of about 80 to 85%, and the preliminarily dewatered sludge is transferred to a sludge receiving hopper A. When stored in the medium, the medium oil is added to the sludge in a weight ratio of 1/2 or the same amount as the sludge.

As described above, when the sludge and the medium oil are mixed and sent from the pressure pump B to the pretreatment tank C, the medium oil is interposed as a lubricating oil on the inner wall of the transfer line, thereby facilitating the pressure feeding. Are stored in the pretreatment tank C once.

Next, by reducing the pressure in the cooker D, the sludge in the pretreatment tank C is sucked into the cooker D together with the medium oil.

In the cooker D, the sludge mixed with the medium oil is heated by the steam in the jacket portion of the cooker D so that the medium oil becomes a heating oil, and the sludge is subjected to oil temperature dehydration.

The decompression operation in the cooker D is usually
Initial stage depressurization, middle stage depressurization, and late stage decompression are performed, and the latter stage depressurization is a depressurization almost close to vacuum.

The steam generated in the cooker D is subjected to sieving of particles by a mist catcher E, and only the steam reaches the condenser F.

The steam is drained by the condenser F and collected as condensed water.

This condensed water is oil-temperature dewatered water, has no bad odor, and has an amount of PPM less than an allowable amount.

The dried sludge dewatered in the cooker D is taken out to the cooker receiving tank G to remove oil, and then crushed by a centrifugal separator so as to become a powdery product having an oil content of about 6%.

The product after oiling contains oil in a small amount, so that it can be used as a fuel burner, and because it contains various organic substances, it can be used as fertilizer.

In the embodiments of the present invention, the sludge is not limited to sludge generated from sewage treatment products, but it is not limited to sludge from kitchen waste and sludge such as viscera, bones, blood, etc. of animals from slaughterhouses and waste fish. The types of sludge are not limited, such as sludge such as waste sludge, waste sludge from food factories and washing water, and human sludge such as human waste sludge.

Further, by treating sludge by the above-described method, the following features are further obtained.

That is, salt is contained in general sludge such as sewage sludge. When oil temperature dehydration is performed in a cooker, the salt contained in the raw material in the process of oil temperature dehydration flows out into the heating oil. Migrated, no salt remained in the dewatered sludge tissue,
Therefore, it can be used as a fertilizer that dislikes salt.

Further, the salt transferred to the heating oil can be easily separated from the oil by washing the oil with water.

This principle is the same when kitchen sludge is used as a raw material. Since not only salt but also sulfide gas can be removed, a rubber incinerator can be used even when kitchen sludge is subjected to oil temperature dehydration and incinerated. No sulphide gas is generated. Naturally, it can also remove the adverse effects of salt when used as fertilizer.

The separation of oil and salt can be easily performed by washing with water.

[0032]

According to the present invention, the medium oil is not stored in the cooker in advance, but is introduced into the cooker together with the sludge raw material. The oil mixture can be sent, and when stored in the cooker, the medium oil will apply oil to the inner wall of the cooker, further improving the heat transfer efficiency of heating from the cooker jacket. Has an effect that can be.

[Brief description of the drawings]

FIG. 1 is a system diagram used for implementing the method of the present invention.

[Explanation of symbols]

 A Sludge receiving hopper B Pressure pump C Pretreatment tank D Cooker E Mist catcher F Condenser G Cooker receiving tank

Claims (1)

[Claims] 1. A sludge treatment system comprising a sludge receiving hopper, a pressure pump, a pretreatment tank, a cooker in which the inside is decompressed and contains heating oil, a mist catcher, and a condenser. A sludge treatment method characterized by adding medium oil to sludge in a sludge receiving hopper so as to fulfill a function of lubricating oil when pumping the sludge into a pretreatment tank by a pump.