JP2842979B2 - Method of producing intermediate sludge from sulfuric acid sludge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing intermediate sludge from sulfuric acid sludge, and more particularly, to a technique for treating sulfuric acid sludge, and more particularly to a method for treating sulfuric acid sludge into a useful substance, particularly asphalt.

[0002]

2. Description of the Related Art In recent years, a large amount of oil in a used crankcase has been generated by an automobile engine.
Due to such problems and the chronic problem of lack of oil, an oil reprocessing industry has been developed. During the reprocessing of such oils, by-products such as "acid sludg
e) a toxic substance is produced. The amount (volume) of the sulfuric acid sludge obtained in the reprocessing step is approximately 2 times the amount (volume) of the used oil subjected to the reprocessing.
It reaches 0-30%.

Conventionally, this sulfuric acid sludge has been discarded. However, sulfuric acid sludge is harmful to the environment because it is strongly acidic and contains heavy metals and various toxic substances. Sulfuric acid sludge is a substance that cannot be decomposed by microorganisms. Therefore, a need has arisen to remove or convert sulfuric acid sludge to useful materials.

From the standpoint of protecting the environment against sulfuric acid sludge, an intermediate product (intermediate sludge) can be produced from the sulfuric acid sludge in a manner similar to that of asphalt using bituminous materials. It is desirable to develop a method to do this. If such a method is developed, good economic and environmental benefits can be obtained. Particularly preferred is that environmental and ecological pollution caused by the sulfuric acid sludge treatment is eliminated.

[0005] Sulfuric acid sludge is a waste treatment substance produced when refining used oil. One of the purposes of such refining of used oil is to purify an oil having characteristics of unused oil from used oil.

[0006] In order to purify the used oil to obtain an oil having substantially the same properties as the unused oil, the used oil must be treated with sulfuric acid. That is, sulfuric acid is added to the used oil to oxidize carbonaceous impurities, metal substances, and other oxidizable substances, and remove the oxidizable substances from the used oil. By the addition of such sulfuric acid, the used oil is separated into two phases. That is, it is separated into a relatively pure oil layer and a sulfuric acid sludge layer. When the sulfuric acid sludge sinks, it is removed. The volume of the sulfuric acid sludge obtained in this way is the same as the used sulfuric acid (98%
Concentration) of about 5%. Also, its pH (p
H) The value is smaller than 2 and generally 0.1. That is, the sulfuric acid sludge is considered to be highly acidic and toxic. Also, decomposition by microorganisms is not possible. In view of the properties of such sulfated sludge, most federal and state government environmental agencies in the United States are increasingly restricting their dumping.

[0007] In the process of refining used oil, a large amount of sulfuric acid sludge is generated. That is, 0.25 gallons of sulfuric acid sludge is generated per gallon of used oil. Prior to 1980, over 2 million tons of acidic waste products were produced each year. At present, the amount of sulfuric acid sludge produced will increase further, but its value is not clear.

[0008]

Traditional methods of treating sulfuric acid sludge include landfills, incineration, acid recovery, acid neutralization, and dumping in water. However, these processing methods have various problems. For example, 30-50% of the components of the sulfuric acid sludge are water-soluble. Therefore, when sulfuric acid sludge is buried in the ground, its components dissolve out into the groundwater surface, which has a serious effect on human health. Further, in the incineration treatment or the acid neutralization treatment, toxic gas is released into the atmosphere. This gas contains substances that cause acid rain, such as sulfur and sulfur dioxide, causing serious damage to forests in Canada, England and Scotland. The process of recovering acid from sulfuric acid sludge is too costly to do this on a small scale. However, it is also difficult to collect the sulfuric acid sludge in one place and perform the acid recovery treatment because of the high transportation cost of the sulfuric acid sludge. The method of dumping and treating wastewater can be implemented only in a place where there is a facility capable of treating a large amount of wastewater sufficient to dilute the sulfuric acid sludge.

[0009] As is clear from the above, the conventional treatment method is very harmful to the environment. In addition, as regulations become stricter, costs for processing are increasing.

On the other hand, a method for producing asphalt by combining sulfuric acid sludge with other substances is disclosed in US Pat.
Nos. 241 and 4,331,481 (Schneider). In this method, sulfuric acid sludge is added to asphalt or a mixture of asphalt and aggregate, which is separately manufactured. However, the amount of sulfuric acid sludge added (ie, treated) is only a small part of the final mixture produced. Therefore, in this method,
Large amounts of sulfuric acid sludge cannot be processed.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method for producing intermediate sludge from sulfuric acid sludge which can treat a large amount of sulfuric acid sludge without polluting the environment, while overcoming the above-mentioned conventional problems. I have.

[0012]

Means for Solving the Problems To accomplish the above object, in order to produce a bituminous material, 3乃
A step of adding a liquid pH adjuster having a pH of 14 to the sulfuric acid sludge to adjust the pH of the sulfuric acid sludge; and a separating step. Although the pH of the sulfuric acid sludge is increased to such an extent that the molten state is not maintained, the pH is not increased to such an extent that the sulfuric acid sludge becomes granular at room temperature and becomes non-melting, and as a result, the liquid layer and 3 to 7 And an intermediate mixture containing an intermediate sludge layer having a pH of 2. The separation step separates the liquid layer from the intermediate sludge layer containing the intermediate sludge and reduces the temperature of the separated intermediate sludge to 2 degrees Celsius.
A method is provided for producing intermediate sludge from sulfuric acid sludge rising from 00 to 275 degrees . As a preferred embodiment, the following steps are provided. Oxidizing the heated intermediate sludge to produce bron asphalt. The liquid pH adjuster is a water-soluble inorganic liquid. The water-soluble inorganic liquid is water. Before the separation step, heating the sulfuric acid sludge at least during the step of adding the pH adjuster to the sulfuric acid sludge. Before the separation step and at least the pH
A step of stirring the sulfuric acid sludge during the step of adding the adjusting agent to the sulfuric acid sludge; heating the sulfuric acid sludge before the separation step and at least during the step of adding the pH adjusting agent to the sulfuric acid sludge. And heating the intermediate sludge to 200 to 275 degrees Celsius, and passing air or oxygen through the intermediate sludge to sufficiently oxidize the intermediate sludge. The air or oxygen is from about 1.416 to 4.248 cubic centimeters.
Passing the intermediate sludge at a flow rate of meters / minute; the intermediate sludge being heated to 270 degrees Celsius; and the air or oxygen passing through the intermediate sludge at a flow rate of 4.248 cubic meters / minute for 10 hours. .

[0013] The present invention also provides a bitumen material.
Lime, caustic soda or soda ash
Sulfuric acid sludge with a solid pH adjuster selected from
To adjust the pH of the sulfuric acid sludge by adding
The pH adjusting step is performed at 190 ° C. with the sulfuric acid sludge.
The sulfuric acid so as not to become granular and still maintain a molten state.
Raises the pH of the sludge, but the sulfuric acid sludge becomes granular at room temperature.
Do not raise the pH to such an extent that the
As a result, an intermediate sludge having a pH of 3 to 7 is obtained.
The mixture containing sludge is washed with water and the intermediate sludge is washed.
Liquid components are removed from the sludge and the temperature of the intermediate sludge is set in Celsius.
Intermediate waste from sulfuric acid sludge rising to 200 to 275 degrees
It provides a way to generate ludge.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method of the present invention, asphalt is produced from sulfuric acid sludge. In the first step, the pH of the sulfuric acid sludge is increased, but the pH is not increased to such an extent that the sulfuric acid sludge becomes granular at room temperature. However, the pH is increased to such an extent that the sulfuric acid sludge does not become granular when heated. It is desirable that the pH value be 3 to 7. In order to increase the pH of the sulfuric acid sludge, various kinds of materials are mixed in the sulfuric acid sludge, although the kind is restricted. Generally, water is used, but an acid having a high pH, a weak or strong base, and a salt solution are preferably used in this order.

[0015] The sulfuric acid sludge having an increased pH becomes an intermediate sludge and is used as commercially useful "bron asphalt" or hard oxidized asphalt. Methods for producing bron asphalt from intermediate sludge are known. Generally, the intermediate sludge should be between 200 degrees Celsius and 27 degrees Celsius.
Heat to 0 degrees, preferably 270 degrees, and allow air bubbles to pass through the intermediate sludge for 10 to 20 hours. The flow rate of the bubbles is preferably 1.416 cubic meters / minute . Increasing the heating temperature while increasing the flow rate of the bubbles can shorten the time required for forming the bron asphalt. The penetration indicating the hardness of the asphalt produced is preferably from 6 to 15
It is.

A method for producing intermediate sludge according to one embodiment of the present invention will be described with reference to FIGS. This example relates to a method for producing intermediate sludge from sulfuric acid sludge, and the produced intermediate sludge is made into an asphalt mixture by a known method.

The method according to the present embodiment includes the following steps. First, sulfuric acid sludge is supplied (step 10).
A pH adjuster is brought into contact with the sulfuric acid sludge to obtain a mixture having a high pH (steps 12 and 14). pH adjusters have high p
It is a liquid or solid substance having an H value. The mixture of pH adjuster and sulfuric acid sludge is non-granular, ie, viscous at room and elevated temperatures. Next, the pH adjuster is separated from the mixture (steps 18, 19, 21). Intermediate sludge useful for asphalt formation can be created by contacting a pH adjuster with sulfuric acid sludge.

The sulfuric acid sludge as a starting material used in the method of the present invention is produced in a lubricating oil regeneration process, and is generally obtained as a by-product in a regeneration step in which sulfuric acid and clay are mixed into waste oil. Sulfuric acid sludge is difficult to define chemically, but it usually contains sulfuric acid esters, sulfonic acids, salts of nitrogen bases, resinous asphalt materials, sulfur components dissolved from oil, hydrocarbon polymers, concentrated products and entrained oil. Contains. The components of the sulfuric acid sludge vary depending on the properties of the oil, processing conditions and storage time.

The sulfuric acid sludge used in the present invention may be one obtained by any kind of oil refining process as long as it uses an acid. The refining of used mineral lubricating oil used in industrial or automotive applications with acid and clay is sulfuric acid sludge, but it is also something that is temporarily stored in storage tanks. You may. Usually, the pH value of the sulfuric acid sludge is about 3 or less, but in general, it often takes a value near 0.1.

It is desirable to produce a high pH intermediate sludge from sulfuric acid sludge to create a useful end product called bron asphalt. Bron asphalt is a specific type of asphalt and has high commercial value. In order to form this asphalt, it is necessary to remove water by heating to an appropriate temperature. However, when heated to such a temperature, the sulfuric acid sludge having a pH value of about 0.1 is immediately converted into an insoluble sandy mixture. This sandy mixture is inconvenient for forming asphalt.

Therefore, in the present invention, the pH of the sulfuric acid sludge is adjusted to pH.
The sulfuric acid sludge p is brought to such an extent that it does not become granular at both room temperature and heated state by contacting the regulator.
The H value was increased. FIG. 2 is a flowchart illustrating a method for producing bron asphalt from sulfuric acid sludge. This method includes the following steps. First,
A pH adjuster having a pH value of preferably 3 to 7 is brought into contact with the sulfuric acid sludge to increase the pH value of the sulfuric acid sludge (step 23). Next, the liquid pH adjuster and the intermediate sludge layer are separated (Step 25). Then, intermediate sludge (2
1) is heated to 200-275 ° C. (step 29).
Then, oxidation treatment is performed so that the heated intermediate sludge has a penetration of 6 to 15 (step 31).

The process for increasing the pH of the sulfuric acid sludge is shown in step 23. pH to increase the pH value
It is desirable to mix a liquid having a value sufficiently larger than 0.1, preferably a liquid having a pH value of 3 or more, into the sulfuric acid sludge. The pH adjuster for raising the pH value may be a solid substance. It is preferable to use water as the pH adjuster. Sulfuric acid sludge and water are mixed to raise the pH value to such an extent that the mixture does not become granular at the time of heating, but the pH value is too high so that the mixture does not become granular at room temperature.

The pH value of the pH adjusting agent used in the present invention has a functional relationship with sulfuric acid sludge. That is, if pH
If the pH value of the adjusting agent is too high or if the pH adjusting agent is mixed in a large amount, the sulfuric acid sludge becomes granular at room temperature. On the other hand, if the pH value of the pH adjuster is too small,
When the temperature of the mixture of the pH adjuster and the sulfuric acid sludge is increased, the sulfuric acid sludge becomes granular. Therefore, the pH adjusting agent to be added must have a pH value such that the pH value of the sulfuric acid sludge is in the range of about 3 to 7.

The liquid pH adjuster can be selected from water, inorganic liquids, organic liquids and dilute acids or bases. In particular, the pH adjuster is preferably selected from diluted strong acids, weak acids, salt solutions, and diluted bases such as lime, ammonia, caustic soda or soda ash. pH of pH adjuster
The value is preferably in the range from 3 to 14, most preferably using water as pH adjuster. Water is generally inexpensive and can be said to be the most preferred pH adjuster due to its characteristic pH value of about 7.

The amount of pH adjusting agent required in carrying out the method of the present invention depends on the initial pH value of the sulfuric acid sludge, the amount of the sulfuric acid sludge and the pH value of the pH adjusting agent used.
The amount of the pH adjuster is an amount necessary for removing or neutralizing the residual sulfuric acid in the sulfuric acid sludge, thereby raising the pH value of the sulfuric acid sludge to be in a range of about 3 to 7. pH
The amount of the adjusting agent or the pH value of the pH adjusting agent will be determined according to the situation. For example, when water is used as the pH adjuster, about 3 to 7 times the volume of sulfuric acid sludge is required. On the other hand, when the caustic solution having a pH value of 7 or more is used as the pH adjuster, the required amount is smaller than that of water.

Since not all the components of the sulfuric acid sludge dissolve in the liquid pH adjuster, the liquid pH adjuster and the sulfuric acid sludge cannot be a homogeneous mixture. Without stirring, the liquid pH adjuster and sulfuric acid sludge separate into two layers.
Also in the method according to the present invention, after the sulfuric acid sludge is sufficiently mixed with the pH adjusting agent, the liquid pH adjusting agent and the sulfuric acid sludge are separated into two layers, a liquid layer and an intermediate sludge layer. Sulfuric acid and other water-soluble components of the sulfuric acid sludge starting material are contained in the liquid layer.

This liquid layer is removed from the sulfuric acid sludge,
Discarded as shown in step 18 of FIG. 1 and step 25 of FIGS. In order to remove the acid liquid layer from the sulfuric acid sludge, a method such as decanting, suction, or separation is used. After removing the liquid layer, the pH of the sulfuric acid sludge
Continue mixing the liquid pH adjuster into the sulfuric acid sludge until the value is approximately 3-7. PH of the generated intermediate sludge
The value is determined by the number of strong acids. Since the method for measuring the number of strong acids is well known, the description is omitted here. The standard test method is ASTM Standard 1980 D974,
This is explained in the section "Petroleum products and lubricating oils" in section 23. In the method described herein, a strong acid number is measured by placing a sample of sulfuric acid sludge in boiling water. The pH value of the water can be measured with a pH test paper or a pH meter. The pH test paper can measure the pH value in the range of 1 to 14.

FIG. 3 shows a flow chart when a solid pH adjuster is used. As the solid pH adjuster, lime, caustic soda, soda ash and the like are used. Liquid p
The solid pH adjuster is brought into contact with the entire surface of the sulfuric acid sludge as in the case of using the H adjuster. However, solid p
When an H adjuster is used, there is no liquid layer as was the case when a liquid pH adjuster was used. When a solid pH adjuster such as caustic soda or lime is used, these substances react with sulfuric acid to form salts and water. Thus, after the addition of the solid pH adjuster, the mixture is washed with a liquid such as water (step 32) to remove residual material produced by the solid pH adjuster, and then the liquid is separated from the sulfuric acid sludge (step 32). 25). After completing the washing and separation, the process shown in FIG. 3 proceeds to the same process as shown in FIG. Alternatively, after mixing the solid pH adjuster with the sulfuric acid sludge, the mixture may be heated as shown in step 29 of FIG. 3 without performing the washing and separation shown in steps 32 and 25 of FIG. . Thereafter, the method shown in FIG. 4 follows the same method as the method shown in FIG.

Preferably, the entire surface area of the sulfuric acid sludge contacts the pH adjuster. Therefore, in the present invention, as shown in step 22 of FIGS. 5 to 7, the mixture of the pH adjuster and the sulfuric acid sludge is stirred. Stirring the mixture of pH adjuster and sulfuric acid sludge increases the degree of contact between the pH adjuster and the entire surface area of the sulfuric acid sludge. The stirring is performed to the extent necessary to disperse the pH adjuster in the sulfuric acid sludge. The stirring is performed by mixing, stirring, dispersing, vibrating, rocking, milling, rotating, and blending.

A method for producing intermediate sludge according to a second embodiment of the present invention will be described with reference to FIGS.
As shown in step 24 of FIGS. 6 and 7, the temperature of the mixture of the pH adjuster and the sulfuric acid sludge increases during the step of contacting the pH adjuster with the sulfuric acid sludge. Sulfuric acid sludge is highly viscous and does not mix easily with pH adjusters. Therefore, by increasing the temperature of the sulfuric acid sludge at least during the pH adjusting agent addition step and the pH adjusting agent and sulfuric acid sludge contacting step,
Sulfuric acid sludge increases the surface area in contact with the pH adjuster. The heating temperature is not determinative, but the desired result is obtained at 100 degrees Celsius or more, preferably 190 degrees Celsius.

FIG. 7 shows a process for producing bron asphalt from sulfuric acid sludge. In the process of FIG. 7, first, a sulfuric acid sludge is prepared in step 10, and in steps 12 and 14, the sulfuric acid sludge is brought into contact with a pH adjuster. Step 22
The mixture of the pH adjuster and the sulfuric acid sludge is stirred and heated in steps 24 and 24. In step 26, the liquid pH adjuster is separated from the intermediate sludge layer and the liquid is removed. Heat the intermediate sludge at a temperature of ~ 275 ° C. Next, in step 30, preferably 1.416 to 4.248 cubic meters per ton
The sludge is dewatered and dried and oxidized by introducing air bubbles into the heated mixture at a rate of 1 / min to produce an asphalt mixture. The oxidation step is continued until the penetration reaches 6 to 15, preferably 8 to 10. The time required for this depends on the heating temperature and the rate of introduction of bubbles into the intermediate sludge. For example, air bubbles are introduced for about 10 hours, the temperature of the intermediate sludge is 250 degrees Celsius, and the air bubble introduction rate is 1.416 cubic centimeters.
Torr / minute , the resulting asphalt mixture has a penetration of 8 at 25 degrees Celsius and 100 grams for 5 seconds, an R & B softening point of 100 degrees Celsius and a flash point of 250 degrees Celsius . Heating at a higher temperature to increase the bubble flow rate can shorten the process time.

The purpose of the pH adjusting steps 12 and 14 is to prevent the formation of particulate matter that hinders the melting required for asphalt formation. The purpose of the heating step 28 is to remove water-soluble compounds. The oxidation step 30 is necessary to increase the brittleness of the asphalt obtained.

In steps 28 and 30, the temperature of the intermediate sludge is heated to 270 degrees Celsius, and 4.248 cubic meters /
Bubbles are introduced into the heated mixture at a flow rate of 10 minutes per minute .

The quality of asphalt is classified according to its penetration and softening point. Typical soft asphalts have a penetration of 60 to 150 or more, and hard asphalts have a penetration of 4 to 20 or 25.

The resulting bitumen material (such as asphalt) has a variety of uses. For example, the asphalt mixture of the present invention is a soft and hard asphalt product,
It can be used for water-resistant products, rust-proof products, moisture barrier products, undercoat products, underlay products, lower sealants, primers, paints, insulating materials, laminations, battery seal materials, and pavement materials. In particular, the bitumen material obtained by this step has utility in that it is used as a hard asphalt mixture. Further, the hardness can be further increased by adding intermediate sludge to soft asphalt.

[0036]

According to the method for producing intermediate sludge from sulfuric acid sludge of the present invention described in detail above, sulfuric acid sludge can be used effectively and there is no need for disposal. In addition, various problems that occur when disposal is performed can be solved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of the generation method of the present invention.

FIG. 2 is a flow chart of the method of the present invention using a liquid pH adjuster.

FIG. 3 is a flow chart of the method of the present invention for producing bron asphalt from sulfuric acid sludge, using a solid pH adjuster and including a liquid washing step.

FIG. 4 is a flow chart of the method of the present invention for producing bron asphalt from sulfuric acid sludge using a liquid pH adjuster.

FIG. 5 is a schematic view of an example of the production method of FIG. 1 in which the contacting step is promoted by stirring.

FIG. 6 is a schematic view of another example of the production method of FIG. 1, in which the contact step is accelerated by heating.

FIG. 7 is a schematic view of still another example of the production method of FIG. 1 in which the contacting step is promoted by stirring and heating, and the step of producing bron asphalt from intermediate sludge is described in detail. Is what you are doing.

[Explanation of symbols]

 10 Sulfuric acid sludge 21 Intermediate sludge

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C10M 175/00-175/04 C02F 11/00-11/20 C10C 3/00-3/18 B09B 3/00

Claims (11)

(57) [Claims] 1. To produce a bituminous material, 3
A step of adding a liquid pH adjuster having a pH of from 14 to 14 to adjust the pH of the sulfuric acid sludge, and a separating step. Although the pH of the sulfuric acid sludge is increased to such an extent that the molten state is not maintained, the pH is not increased to such an extent that the sulfuric acid sludge becomes granular at room temperature and becomes non-melting, and as a result, the liquid layer and 3 to 7 And an intermediate mixture containing an intermediate sludge layer having a pH of 3 is obtained. In the separation step, the liquid layer is separated from the intermediate sludge layer containing the intermediate sludge, and the temperature of the separated intermediate sludge is measured in degrees Celsius.
A method for producing intermediate sludge from sulfuric acid sludge, wherein the intermediate sludge is raised to 200 to 275 degrees . Wherein for generating a blown asphalt, pressurized
The method of claim 1, further comprising oxidizing the heated intermediate sludge. Wherein said liquid pH adjusting agent intermediate sludge generation method according to claim 1, wherein the water-soluble inorganic liquids. 4. The method according to claim 3, wherein the water-soluble inorganic liquid is water. 5. The method for producing a bituminous material, comprising the steps of:
From materials composed of ash, caustic soda or soda ash
The selected solid pH adjuster is added to the sulfuric acid sludge to
Adjusting the pH of the sulfuric acid sludge;
In the process, the sulfuric acid sludge does not become granular at 190 degrees Celsius.
Adjust the pH of the sulfuric acid sludge to such an extent that the molten state is still maintained.
The sulfuric acid sludge becomes granular at room temperature and becomes non-melting
The pH is not raised to such an extent that
An intermediate sludge having H is obtained.
The mixture is washed with water, and liquid mixture is formed from the intermediate sludge.
And remove the intermediate sludge temperature from 200 to 27 degrees Celsius.
From sulfuric acid sludge characterized by rising to 5 degrees, intermediate
How to generate sludge. 6. The method according to claim 1, wherein said p
The method for producing an intermediate sludge according to claim 1, further comprising a step of heating the sulfuric acid sludge during the step of adding the H regulator to the sulfuric acid sludge. 7. The method according to claim 1, wherein said p
The method for producing an intermediate sludge according to claim 1, further comprising a step of stirring the sulfuric acid sludge during the step of adding the H regulator to the sulfuric acid sludge. 8. The method according to claim 1, wherein said p is present before said separation step.
The method for producing an intermediate sludge according to claim 1, further comprising a step of heating and stirring the sulfuric acid sludge during the step of adding the H regulator to the sulfuric acid sludge. 9. The intermediate sludge heating and oxidizing step includes heating the intermediate sludge to 200 to 275 degrees Celsius, and passing air or oxygen through the intermediate sludge to sufficiently oxidize the intermediate sludge to remove the asphalt. The intermediate sludge generation method according to claim 2, wherein 10. The air or oxygen is from about 1.416 to
The intermediate sludge producing method according to claim 9, wherein the intermediate sludge is passed at a flow rate of 4.248 cubic meters / minute . 11. The intermediate of claim 9, wherein the intermediate sludge is heated to 270 degrees Celsius and the air or oxygen passes through the intermediate sludge at a flow rate of 4.248 cubic meters / minute for 10 hours. Sludge generation method.