JPS5822068B2 - Fluidization method for petroleum sludge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for fluidizing petroleum-based sludge.

More specifically, the present invention relates to a fluidization method for dissolving and dispersing sludge deposited at the bottom of a petroleum crude oil tank or heavy oil tank in an oil-based solvent and then discharging and collecting it.

When petroleum-based crude oil or heavy oil is stored in a tank for a certain period of time, fine powder, wax, etc. mixed in the crude oil or heavy oil are deposited, and petroleum-based sludge is formed at the bottom.

This sludge sticks to the bottom of the tank and must be drained away, since it reduces the effective volume of the tank and reduces the effective use of resources.

However, discharging and removing such sludge is difficult and complicated.

Various methods can be considered to discharge and remove sludge outside the tank, but the method of dissolving and dispersing it in an oil-based solvent to fluidize it and discharge it is the most effective method for reusing recovered oil and effectively utilizing sludge. From this point of view, it is generally considered to be a preferable method.

At that time, in the generally known method, the oil-based solvent necessary to fluidize the sludge is placed on the upper left side of the sludge, and then dissolved and dispersed by adding means such as heating, stirring, and adding chemicals. efforts are being made to promote this.

However, such methods are extremely unsatisfactory as it takes a long time to dissolve and disperse the sludge.

The present invention has been made to eliminate the various drawbacks of the conventional methods as described above, and uses at least two processing agents selected from the group consisting of petroleum-based solvents, tar-based solvents, and surfactants. The method is characterized in that a relatively small amount of the sludge is used to heat the sludge, and then an amount of oil-based solvent necessary to fluidize the sludge is added to mix and disperse the sludge in the oil-based solvent. This is a method for fluidizing petroleum sludge.

Petroleum-based sludge in the present invention refers to sludge that solidifies and settles at the bottom of tanks, tankers, etc. when storing or transporting heavy oil such as petroleum-based crude oil or heavy oil.
It is a combination of rust, water, wax, oil, polymeric substances, etc.

According to the invention, the fluidization process is carried out in two stages.

First, in the first stage, a relatively small amount of at least two treatment agents selected from the group consisting of petroleum solvents, tar solvents, and surfactants are added to the sludge, and the sludge is heated and treated. Keep it as soft as possible.

Then, in the second stage, the amount of oil-based solvent necessary to fluidize the sludge is added as the left front, and a means of stirring and mixing is added to mix and disperse the sludge into the oil-based solvent, thereby fluidizing the sludge. It is something.

The processing agent used in the first stage is a small amount selected from the following three types: petroleum-based solvents, tar-based solvents, and surfactants.
It is necessary that the mixture contains seeds.

As the petroleum solvent, crude oil, heavy oil (A heavy oil, B heavy oil, and C heavy oil), light oil, etc. can be used.

The pour point of the petroleum solvent used in the first stage is preferably lower than the pour point of the oil solvent used in the second stage.

In addition, tar-based solvents include xylene volume oil obtained from light oil obtained from coke gas, coal tar, naphthalene oil obtained by distilling coal tar, methylnaphthalene oil, absorption oil, anthracene oil, and creosote. Boiling point of oil, pot residue, or mixtures thereof, etc.: 130
℃ or higher and a relatively heavy coal tar-based distillate having a specific gravity of about 0.09 or higher is preferred.

Various types of surfactants can be used.

For example, anionic surfactants include alkylbenzene sulfonic acids and their salts, alkyl sulfates and their salts, polyoxyalkylene alkyl ether sulfates and their salts, polyoxyalkylene fatty acid ester sulfates and their salts. , polyoxyalkylene alkylphenyl ether sulfates and their salts, dialkyl sulfosuccinates and their salts, α-sulfo fatty acids and their salts, α-sulfo fatty acid alkyl esters and their salts, α-olefin sulfonic acids and their salts, Examples include alkanesulfonic acids and their salts, petroleum sulfonic acids and their salts, alkyl phosphates and their salts, polyoxyalkylene alkyl ether phosphates and their salts, fatty acid soaps, and the like.

In addition, as nonionic surfactants, polyoxyalkylene alkyl ether, polyoxyalkylene alkylphenyl ether, polyoxyalkylene fatty acid ester, sorbitan fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, fatty acid monoglyceride,
Polyoxyalkylenealkylamine, pluronic type poly(oxyethylene)-poly(oxypropylene)
Cocondensate, tetronic poly(oxyethylene)
Examples include poly(oxypropylene) cocondensates.

As the cationic surfactant, quaternary ammonium salts such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, and alkyldimethylbenzylammonium salts are mainly used.

N-alkylglycine, dimethylalkylbetaine, etc. are used as amphoteric surfactants, but cationic surfactants and amphoteric surfactants are generally expensive;
Considering that the composition of the present invention is used, for example, as a fuel, it is preferable to use a relatively inexpensive anionic surfactant or nonionic surfactant in the present invention.

Incidentally, the surfactants that can be used in the present invention are not limited to those exemplified.

Therefore, the combinations of processing agents in the present invention are: (1) petroleum solvent - tar solvent CB) petroleum solvent - surfactant (C) tar solvent - surfactant (D) petroleum solvent - tar solvent - Surfactant 4
There is a street.

Therefore, in any combination, it is necessary that the amount is relatively small compared to the total amount of petroleum solvent and tar solvent + J sludge, and preferably 0.5 to 2 times the volume of sludge. It will be done.

Furthermore, in combinations A and D, the amount of tar-based solvent used is 0.01% by volume or more, preferably 1% by volume or more based on the sludge.

The amount of surfactant used is from 0.01 to 10% by weight, preferably from 0.01 to 1% by weight, based on the sludge.

Note that one of the features of the present invention is that the fluidization of the sludge is carried out in two stages, and that at least two types of treatment agents as described above are used in the first stage.
In the first stage treatment, it is sufficient to use a relatively small amount of treatment agent, and there is no need to place any particular restrictions on the type of surfactant.

The heating conditions in the first stage vary depending on the properties of the sludge, but are usually 50 to 80°C, preferably near the pour point of the sludge, for half a day to several days.

During heating, it is preferable that the liquid phase is in a fluid state.

However, even if a stirrer is installed in the tank, it is often not possible to use the stirrer in the first step, which uses a relatively small amount of processing agent, and in that case, it may be left standing.

The second stage treatment is a process in which the sludge softened in the first stage treatment is dissolved and dispersed in an oil-based solvent added separately. At this time, the sludge is stirred and mixed to maintain good contact with the oil-based solvent. Perform the following operations.

The treatment temperature at this time may be lower than the treatment temperature in the first stage, and is usually carried out at room temperature to 70°C.

The amount of oil-based solvent used in the second stage must be sufficient to ensure that the recovered oil has sufficient fluidity when the sludge is sufficiently dissolved and dispersed; The amount used is approximately 2 to 10 times the capacity.

Note that the calculation of the amount of oil-based solvent also includes the petroleum-based solvent and tar-based solvent used in the first step.

However, as the oil-based solvent, petroleum-based solvents, tar-based solvents, etc. used in the first stage treatment can be used.
It is not necessarily necessary to use the same solvent as in the first step.

As described above, the method of the present invention comparatively eases the dissolution and dispersion of sludge into an oily solvent by stirring and mixing in the second stage, which is the main treatment operation, by performing the first stage treatment preliminary. The reason is that a high dispersion rate can be ensured even if the process is carried out under the same conditions.

Therefore, the method of the present invention is particularly effective when the sludge has a high pour point.

Next, the method of the present invention will be explained in more detail with reference to Examples.

Example 1 200 g of Minas heavy oil-based tank sludge having the analysis values shown in Table 1 was loaded into the bottom of a beer tank with a capacity of 11, and on top of it was added Minas heavy oil 2001 and a drug of 0.2 weight to the sludge. % nonionic surfactant (
After charging polyoxyethylene (20 mol) sorbitan monooleate) and an aromatic hydrocarbon solvent (tar solvent) (boiling point 250 to 300°C) equivalent to 1% by volume, the mixture was allowed to stand still for 24 hours in a 75°C water bath. I placed it.

Next, an additional 600ml of Minas heavy oil was charged, and while the center of the liquid was gently stirred at 65°C, the upper layer liquid was sampled at regular intervals to analyze the wax content, thereby determining the solvent content of the sludge. The dispersion rate was estimated.

The results are shown in Table 2. Example 2 In the method of Example 1, 20% of A heavy oil was used instead of Minas heavy oil.
When the same method was carried out except that 0 ml was used, the results shown in Table 2 were obtained.

Comparative Example 1 200 g of the same sludge as in Example 1 and 800 g of Minas heavy oil
m1 is a nonionic surfactant (polyoxyethylene (20 mol) sorbitan monooleate) equivalent to 0.2% by weight based on the sludge, and a tar-based solvent (boiling point 250-300) equivalent to 1% by volume. When the mixture was initially stirred at 65°C, the results shown in Table 2 were obtained.

Comparative Example 2 The same method as Comparative Example 1 was carried out except that 200 ml of A heavy oil and 600 ml of Minas heavy oil were used instead of 800 ml of Minas heavy oil, and the results shown in Table 2 were obtained.

Example 3 30) tons of Minas heavy oil sludge (pour point 82.
In a cone roof type tank with a capacity of 300 doors in which 5°C) is deposited, 20 tons of heavy oil A and an anionic surfactant (sodium di-2-ethylhexyl sulfosuccinate) of 0.2% by weight based on the sludge are placed. and aromatic hydrocarbon solvent (tar solvent) (boiling point 250
~300°C) and heated at 75°C for 18 hours in a stationary state.

Next, an additional 80 tons of Minas heavy oil was charged, and the temperature was increased to approximately 65°C.
After stirring and mixing by pump circulation for 56 hours, the mixture was allowed to cool to about 50°C and shifted to an oil layer.

The amount remaining at the bottom was 4.2 doors, about half of which was hard sludge and the rest was viscous solvent.

In addition, after the first stage treatment (standing), the solvent and bottom sludge were collected and analyzed, and it was found that approximately 30% of the amount at the start of treatment
It was found that approximately 20% of the sludge was dispersed in the solvent, and about 20% of the sludge layer was oil that had penetrated, and the pour point of the sludge layer was lowered to 70°C.

Claims (1)

[Claims] 1. At least two types of treatment agents selected from the group consisting of petroleum-based solvents, tar-based solvents, and surfactants are used in relatively small amounts for petroleum-based sludge, and the sludge is heated. A method for fluidizing petroleum-based sludge, which is characterized in that the sludge is then mixed and dispersed in the oil-based solvent by adding an amount of oil-based solvent necessary to fluidize the sludge. 2. The fluidization method according to claim 1, wherein the total amount of petroleum solvent and tar solvent in the treatment agent is 0.5 to 2 times the volume of the sludge. 3 The amount of surfactant is 0.01 to 10% relative to the sludge.
% by weight. Fluidization method according to claim 1. 4. The fluidization method according to any one of claims 1 to 3, wherein the heating temperature using the processing agent is 50 to 90°C. 5. The fluidization method according to any one of claims 1 to 4, wherein the processing agent is composed of three types: a petroleum solvent, a tar solvent, and a surfactant. 6. The fluidization method according to any one of claims 1 to 5, wherein the oil-based solvent used after the heating treatment is used in an amount of 2 to 10 times the volume of the sludge. 7. The fluidization method according to claim 6, wherein the oil-based solvent is selected from the group consisting of petroleum-based solvents and tar-based solvents.