JPS63141700A - Degradation treatment of oil-containing water sludge - Google Patents

Abstract

PURPOSE:To permit inexpensive and easy degradation of oil-contg. water sludge by adding granular quicklime and surfactant to the oil-contg. water sludge, kneading the sludge and subjecting the sludge to drying in the sun, thereby reducing and degrading the sludge. CONSTITUTION:The granular or lump quicklime, >=50wt.% of which consists of 1-20mm grain size, is added at 1-55wt.% and the surfactant (e.g., sodium alkylbenzene sulfonate) is added thereto at 0.1-10wt.% of the weight of the quicklime to the oil-contg. water sludge which is subjected to a pretreatment such as centrifugal sepn. at need or has <=90wt.% moisture by a distillation method equiv. to the moisture content of the sludge subjected to said treatment, then the sludge is kneaded and is treated without applying heat thereto from the outside. If necessary, the sludge is aged for 1-3 days and is dried in the sun, by which the moisture is evaporated and absorbed to reduce volume and the sludge is degraded. As a result, the treatment is realized at the low treat ment cost without entailing large equipment investment. The treated sludge having a high oil content is usable as solid fuel.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to oil factories, oil depots, chemical factories, power plants, ships,
The present invention relates to a treatment method for pulverizing oil-containing water sludge (oil-containing, water-containing sludge) discharged from machine factories and the like.

[Background of the Invention] What is generally referred to as oil-impregnated water sludge is, for example, accumulated over a long period of time at the bottom of an oil tank or in an oil separator in a factory. In addition to oil and water, these oily water sludges contain a large amount of altered substances such as mud, carbon, organic impurities, etc., and their apparent viscosity increases and is often accumulated in a mayonnaise-like state. .

Conventionally, these oil-containing water sludges have been treated using methods such as incineration, activated sludge method, combination of physical and chemical methods, addition of surfactants, etc.
Although a series of methods have been proposed, many of the materials are ultimately incinerated (see Japanese Patent Laid-Open No. 57-205491), and the high cost of incineration poses a considerable economic burden.

In addition, for sludge with high oil content, use cement etc.
It has been proposed to reuse it as solid fuel (Special Publications No. 57-43075, No. 57-61075, No. 58).
-40998, JP-A-56-103296, JP-A-57
-80493, 57-190096, 58-5
(Refer to No. 3989) However, in the recent times when the price of oil is rapidly decreasing, the economic value of low-energy solid fuels disappears, and this method is not practical.

[Purpose of the invention] The present invention was developed in response to these times, and was completed as a result of intensive research into how to reduce the processing cost of oil-containing water sludge. This is proposed as a method that can be realized at low processing costs without requiring large capital investments.

That is, the present invention evaporates and absorbs water in oil-containing water sludge to reduce its volume, fixes the oil content, and facilitates handling during transportation for one operation, and also allows materials that need to be incinerated to be burned in a simple incinerator. The purpose of MSl is to provide a treatment method for oil-containing water sludge that allows for incineration and facilitates landfilling of sludge that does not require incineration, and can also be used as solid fuel for sludge with a high oil content. The second object is to provide an extremely simple and low-cost processing method that does not require expensive equipment when pulverizing.

[Structure of the Invention] In order to achieve the above object, the method for pulverizing oily water sludge of the present invention involves performing pretreatment such as centrifugation if necessary, or removing water by a distillation method equivalent to this process. is less than 90% by weight of oil-containing water sludge, and more than 50% by weight is 1-
1 to 55% by weight (preferably 5 to 50% by weight) of granular or lump quicklime with a diameter of 20 mm and 0% to quicklime.
．． 1 to 10% by weight of surfactant is added and kneaded, treated without applying external heat, and if necessary, cured for 1 to 3 days and dried in the sun to evaporate and absorb water to reduce volume. It is characterized by being powdered.

The present invention will be explained in detail below.

In order to avoid confusion, the values of moisture, mud, and oil used in the description of the present invention will be based on the following measurement method.

Moisture: JIS K 2275 (distillation method) Oil content: J
IS K 0120 (Normal hexane extraction method) Sludge content: Sludge content = 1 - Wood content - Oil content %: Weight % This invention targets sludge with a water content of 90% or less among oil-containing water sludges. If the moisture content exceeds 90%, a large amount of quicklime will be used, making it uneconomical.However, if the moisture content exceeds 90%, it is possible to easily reduce the moisture content by performing pretreatment.

Oil-containing water sludge to which the present invention is applied refers to oil factories, oil depots,
Materials discharged from chemical plants (1) power plants, ships (1) machinery factories, etc., from which a large amount of moisture has been easily removed through mechanical processing such as centrifugal dehydrators and filter presses, and sludge that has settled and accumulated in thickening sedimentation tanks or floats. These include sludge and things that have accumulated over a long period of time in oil tanks, etc. These oil-impregnated water sludges usually have a water content of 90% or less and an oil content of 50% or more and are semi-fluid, grease-like or paste-like, and cannot be disposed of in a landfill under current regulations, and can only be disposed of by incineration.

The present invention uses quicklime as a powdering agent, and uses quicklime in the form of granules or lumps, at least 50% of which has a diameter of 1 to 20 liters. Note that the term "diameter" herein refers to the diameter of a spherical body, and in the case of a shape other than a spherical body, the term "diameter" refers to the diameter of the spherical body when converted to the same volume.

Conventionally, proposals have been made to use oil-impregnated sludge or solid fuel from oil-impregnated sludge as quicklime alone or as a mixture of quicklime and other chemicals, but there is no mention of the particle size of quicklime as in the five proposals.

It is well known that when quicklime is left in the air, it absorbs water and turns into slaked lime with heat generation, but none of the above proposals pay attention to this fact. , the most important thing to be careful of is
This is a change in quality due to water absorption during storage. If quicklime were to change into slaked lime due to improper packaging or an extended storage period, the effectiveness of this treatment method would be drastically reduced, the amount of quicklime required for treatment would increase, and this would only lead to a direct increase in treatment costs. This also results in an increase in processing costs after the powdering process. In addition, scattering during the addition and kneading operations of powdered quicklime poses a great danger to workers, and this can also be a major negative factor. For this reason, as a result of various studies, at least 50% of
It has been discovered that using quicklime in the form of granules or lumps with a diameter of 20 m can prevent deterioration during storage and improve safety during work.

[Action of the invention] The effects of quicklime in the present invention include evaporation of water due to heat generated by reaction with water in oil-containing water sludge, generation of slaked lime by the reaction between quicklime and water, and volume reduction due to absorption of water and oil in slaked lime. Regarding the pulverization effect, if quicklime is in the form of granules or lumps, there are concerns that the reaction rate will decrease and the time required for the reaction will increase due to the small surface area, but this concern can be alleviated by using a surfactant in combination. It turns out that it will happen.

This led to the completion of the present invention.

When a surfactant is added at the same time as quicklime, the surfactant lowers the surface tension of the water contained in it, allowing water to easily penetrate into the granular and lumpy quicklime and generate heat, causing the granular and lumpy quicklime to It is crushed into powder and the reaction proceeds easily.

The amount of surfactant added in the present invention is 0.1 to 10% based on the added quicklime, but 0.1 to 1%.
% is a preferred range. If the amount is less than 0.1%, it is difficult to obtain the above-mentioned effects of the present invention, whereas if the amount exceeds 10%, the effect is saturated and the cost is negative. The type of surfactant may be either an anionic surfactant, 1wA ionic surfactant, or nonionic surfactant, but anionic surfactants are suitable, such as sodium alkylbenzene sulfonate, sodium alkyl sulfate ester, etc. Particularly suitable are salts, alkyl sodium sulfates, and the like.

When these surfactants are in bulk form, it is preferable to add them to the oil-impregnated water sludge before addition of quicklime at the time of mixing, and when using powdered surfactants, it is desirable to add them at the same time as quicklime.

It is desirable to change the amount of quicklime added depending on the amount of moisture content; it is economical to increase the amount added when the moisture content is high, and reduce the amount added accordingly when the moisture content is low. . Further, if the amount of quicklime added is increased, the processing time and curing time can be shortened, but the processing cost increases, so it is necessary to maintain the amount of quicklime appropriately depending on the situation.

In the present invention, if the curing period exceeds 3 days, the degree of improvement in the powdering condition will be reduced.

An economically desirable curing period is 3 days or less.

In the case of the present invention, the kneading work does not necessarily require expensive equipment, and if the capacity is small, it is sufficient to perform the kneading work manually in a mixing tank, or it is also possible to use a concrete mixer truck. It is also possible to use a continuous automatic device, and it is only necessary to consider appropriate equipment depending on the throughput.

[Example] The present invention will be explained below with reference to Examples. In addition, hereinafter referred to as “Department”
means "parts by weight".

Example l Sample Properties of oil-impregnated water sludge discharged from an oil refinery ■ Appearance Dark brown, opaque, muddy ■ Moisture 80.7% ■ Sludge content 11.1% ■ Oil content 8.2% To 100 parts of the above oil-impregnated water sludge sample To the mixture, 30 parts of quicklime (90% of granules having a diameter of 1 to 20 sn) and 1 part of dodecylbenzenesulfone soda were added and kneaded for 30 minutes, then left to stand for 2 days and cured in the sun.

The oil-impregnated water sludge was pulverized and transformed into something that was extremely easy to handle. There is no need for external heating during kneading, and the temperature of the sludge reaches a maximum of 125°C due to the heat of reaction, reducing water evaporation.
l1I was measured. After 2 days of solar curing, the total weight hardly increases compared to the control oil-water sludge.

Comparative Example 1 The same oil-impregnated water sludge and the same amount of quicklime as in Example 1 were used, but sodium dodecylbenzenesulfonate was not added. After kneading in the same manner as in Example 1, the mixture was similarly cured in the sun for 2 days.

The maximum temperature during kneading remained at 110°C, and the total weight after 2 days was about 10% higher than the reference oil-water sludge. It was observed that unreacted white quicklime remained in the powdered sludge in the form of lumps.

Comparative Example 2 The same oil-impregnated water sludge as in Example 1 was treated with powdered quicklime that had been stored for 3 weeks at a humidity of 60% after purchase (those with a diameter of less than 11% had a diameter of 70%).
% or more), the same experiment as in Example 1 was conducted, but the maximum temperature during kneading remained at 105° C., and the total weight after curing for 2 days increased by 15%. It is thought that the raw material quicklime absorbed water and deteriorated during storage.

Example 2 In Example 1, the sample table oil-water sludge (moisture 92%, mud content 6
%, oil content: 2%), but the water content was too high and it could not be powdered.

When this sample was centrifuged in a G1 machine (3000 rpm) to remove 60% of water and an experiment similar to Example 1 was carried out, powdering treatment became possible and the total weight was reduced by about 5%.

Example 3 In Example 1, sodium dialkylsulfosuccinate 0.5 was substituted for sodium dodecylbenzenesulfonate.
When a similar experiment was carried out with the only difference that 100% of the sample was used, the reaction was completed in 20 minutes. After 3 days of sun curing, the total weight decreased by 5%.

Example 4 Sample Tank bottom oil property ■ Appearance blackish brown, mayonnaise-like ■ Moisture 45% ■ Sludge content 18% ■ Oil content 37% Quicklime (70% is from 1 to 10 mm diameter) 15 parts of granular material) and 1 part of cetyl sulfate sodium salt were added and kneaded for 30 minutes to powder. After curing in the sun for one day, the total weight was almost the same as the reference oil-water sludge.

Claims (1)

[Claims] If necessary, perform pretreatment such as centrifugation, or use a distillation method equivalent to that which has gone through this process to obtain oil-containing water sludge with a water content of 90% by weight or less, where 50% by weight or more is 1 to 20 mm.
1 to 55% by weight of granular or lump quicklime consisting of a diameter,
Add 0.1 to 10% by weight of a surfactant to quicklime, knead it, and process without applying external heat.
A method for pulverizing oil-impregnated water sludge, which is characterized by curing for ~3 days, drying in the sun, evaporating and absorbing water to reduce the volume, and pulverizing the sludge.