JPH0361716B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for separating and recovering oil and ash from sludge containing oil and ash discharged from a petroleum refining process. Conventional technology The sludge discharged from the petroleum refining process contains
For example, slop tanks and air-floatation devices.
There is an oil sludge obtained from The former contains about 20 to 30% oil, about 4
Contains ~6% solids. The latter is about 5~
Contains 10% oil and approximately 2-4% solids. In addition, the solid content contains useful substances such as Ni, V, Fe, and SiO ₂ . The effective use of useful substances contained in the oil and solid contents of these oil sludges has been studied. Conventionally, as a treatment method for sludge, JP-A-59-
Publication No. 109294 (hereinafter referred to as the conventional method) discloses a technology for separating and recovering iron oxide, a useful component, from sludge (hot rolling sludge) discharged from the treatment process of hot rolling wastewater in a steel mill. However, this conventional method focuses only on the effective use of iron oxide, and cannot be said to be an effective method for simultaneously using oil and iron oxide. In addition, unburned carbon generated by partial oxidation of petroleum hydrocarbons contains solid carbon, ash, and volatile matter, and technology for continuously granulating this solid carbon and technology for separating solid carbon have already been established. There is. Regarding these technologies, please refer to Japanese Patent Publication No. 39-21502, Publication of Utility Model Publication No. 19507-1971, Publication No. 41248 of Utility Model Publication No. 48-48.
This method is described in detail in Japanese Utility Model Publication No. 53-39737. That is, in the process of producing synthesis gas by partial oxidation of hydrocarbons using the Shell gasification method developed by the Shell Group, unburned carbon generated is removed from the synthesis gas by a spray tower using a solid-liquid separator. The wash water discharged from the tower is a black suspension containing fine solid carbon particles. Commercially available "C" heavy oil, for example, is added as a binder to the suspension of the washing water and unburned carbon and stirred. Since solid carbon is inherently lipophilic, the binder is adsorbed onto the surface of the solid carbon particles, and the surface is coated with the binder. The coated particles collide with each other due to stirring, and the particles coagulate due to adhesion, grow further, become compacted, granulate, and are separated from the water. The present invention is an EP suit (petroleum coke combustion ash)
The ash inside has no affinity with petroleum-based binders and is hydrophilic, while solid carbon has a strong affinity with petroleum-based binders, so solid carbon can be produced using the Ciel Group's technology and equipment described in the previous section. It is based on the technical idea of granulating the powder and separating and removing the ash. The same applicant as the present applicant has already filed a patent application for a method for recycling solid carbon granules (pellets) produced using this technology as solid fuel (Japanese Patent Application No. 6508/1982). Problems to be Solved by the Invention The present invention provides a method for separating and recovering the oil and ash contained in sludge discharged from the petroleum refining process and effectively utilizing each of them, particularly for effectively utilizing the oil contained in the sludge. This provides a method to do so. Means for Solving the Problems In other words, the present invention provides an aqueous slurry containing sludge discharged from the petroleum refining process by adding unburned carbon generated during the combustion process of petroleum hydrocarbons to less than twice the amount of oil in the sludge. After adding the above oil as a binder and stirring at 85°C or higher without using a surfactant to granulate oil-containing solid carbon, the pH is adjusted to 7 or less to form sludge and unprocessed carbon. The present invention relates to a method for separating and recovering oil and ash in sludge, which is characterized by separating and collecting an aqueous phase containing ash contained in burnt carbon and solid carbon contained therein. The source of the sludge used in the present invention is not particularly limited as long as it contains oil and ash, but it is particularly oil sludge discharged from slop tanks and air floatation equipment during the petroleum refining process. However, the method of the invention is also applicable to industrial sludge containing other oils. Slop tank sludge has an oil content of approximately 20-30wt%.
About 4-6 wt% solids and the remainder water. Also, air floatation has an oil content of about 5~
10 wt%, ash about 2-4 wt% and the balance water. In the method of the present invention, the unburned carbon added to the oil sludge is unburned carbon generated during the combustion process of petroleum coke or petroleum hydrocarbons and unburned carbon obtained from the combustion process of other carbon sources, Contains solid carbon, ash and oil. An example of the analytical values of the above petroleum coke combustion ash (EP suit) is as follows. Ash content 12.46% by weight, volatile content (oil) 7.20% by weight,
The fixed carbon content is 80.34% by weight, and the density (g/cm ³ ) is 1.880. Granulation conditions The amount of unburned carbon added varies depending on the oil content contained in the sludge used, and is 1.4 to 5 times the amount of unburned carbon based on the weight of oil in the sludge.
Preferably it is 1.4 times the amount. The above-mentioned required amount of unburned carbon is added to the oil contained in the sludge to granulate solid carbon. Granulation is carried out using, for example, a shell pelletizing separator (SPS device). Temperature during granulation is 85℃
Above, preferably 85 to 100°C is appropriate. At the start of granulation, the speed is approximately 1700r.p. even at room temperature (approximately 20℃).
Since the slurry is stirred at a rotational speed of m, it reaches a temperature of 85°C or higher in about 30 minutes due to the heat generated. When increasing the internal temperature of SPS to 100℃,
Pelletization of solid carbon begins after 30 minutes at an internal temperature of 80°C, and the particle size of the pellets reaches 0.2 to 0.3 m/m after 40 minutes at 100°C. Mechanical failure will occur if the internal temperature exceeds 10°C, so it must be cooled to an appropriate temperature (85°C). After 40 minutes at an internal temperature of 85 DEG C., the pellet size reaches 1.0-1.5 m/m. When separating the ash after granulation, the pH is 7 or less, preferably
Adjust to PH3-5. PH is alkaline (PH9.0 ~
The separation of ash content is better when the acidity (3.0 to 5) is higher than that (10 or higher). Examples The present invention will be explained below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. All percentages are by weight. Example 1 The analysis values of the slop tank sludge used as raw materials were: oil content 25.9%, ash content 4.9%, moisture 69.2%, sulfur 0.94%, PH 9.0. After preheating this oil sludge to 80 to 90℃, 500g of it (130g of oil content) and 185g of unburned carbon, which is equivalent to about 1.4 times the oil content, were put into an SPS device along with 2300ml of water, and the rotation speed was adjusted without adjusting the pH. 1700r.
The mixture was stirred at pm for 80 minutes. Temperature is 23℃ to 60℃
After a few minutes, the temperature reached 85°C. The pH of the processing solution after granulation is approximately
It was 4.0. The ash was separated and precipitated while the pH remained at approximately 4.0. The filtrate was 2700ml. The pellets obtained had a particle size of 1.0 m/m. The unburnt carbon used in this example is a volatile component.
7.20%, and a mixture of fixed carbon content of 80.34% and ash content. Example 2 The same slop tank sludge and unburned carbon as in Example 1 were used as raw materials. 500g of oil sludge without preheating and 185g of unburned carbon, which is equivalent to about 1.4 times the amount of oil, along with 2300ml of water.
Put it in the SPS device and set the rotation speed to 1700 r.p. without adjusting the PH.
The mixture was stirred at m for 80 minutes. The temperature reached 85°C after 60 minutes from 23°C. The pH of the processing solution after granulation is approximately
It was 4.0. The ash was separated and precipitated while the pH remained at approximately 4.0. The filtrate was 2700ml, and the pellets obtained had a particle size of
It was 0.5m/m. A comparison between Example 1 and Example 2 shows that when the oil sludge was heated in advance, the pellets had a uniform shape and a larger particle size. Example 3 The same slop tank sludge and unburned carbon as in Example 1 were used as raw materials. Put 500 g of preheated oil sludge and 185 g of unburned carbon into the SPS device along with 2200 g of water.
After adjusting the pH to 9.5 with a 5% NaOH aqueous solution, the mixture was stirred at a rotation speed of 1700 rpm for 80 minutes. When granulated at pH 9.5, the amount of granules (pellets) was small and the ash content was high. In other words, it was found that the separation of oil and ash in the sludge was insufficient. In addition, if the treatment solution after granulation has a pH of 9.5, the settling rate of the precipitate is slow even if it is allowed to stand still. The pH of the processing solution after granulation is 4.
When the mixture was adjusted to Comparative Example 1 500g of oil sludge same as Example 1 (oil content 130g)
g), unburned carbon equivalent to approximately 2.3 times the amount
300 g was put into an SPS device along with 2400 ml of water, and stirred for 60 minutes at a rotational speed of 1700 rpm without adjusting the pH. The temperature reached 100°C after 60 minutes from 23°C.
The pH of the treatment solution after granulation was approximately 4.0. 5 more
% (by weight) of caustic soda aqueous solution to adjust the pH of the treatment solution.
11.0, and the ash was separated and precipitated. The filtrate is
It was 2700ml. As a result, 374 g of pellets and 27 g of ash were obtained. The obtained pellets have a particle size of
It was between 0.5m/m and 1.0m/m. Comparative Example 2 The analysis values of the air floatation sludge used as a raw material were: oil content 8.9%, ash content 2.5%, moisture 88.6%, sulfur 0.51%, and PH 8.0. For 500 g of this oil sludge (oil content 44.5 g), 185 g of unburned carbon (used in Example 1), which is equivalent to about 4.2 times the amount, and 50 g of binder were placed in an SPS device along with 2500 ml of water, and the PH was left unadjusted. Stirring treatment was carried out for 60 minutes at a rotational speed of 1700 rpm. The temperature reached 100°C after 60 minutes from 32°C. The pH of the treatment solution after granulation was 4.0. Another 5%
(by weight) of caustic soda aqueous solution to 11.0
The ash was separated and precipitated. The liquid volume was 2600ml. 244 g of pellets and 21 g of ash were obtained. The particle size of the pellets obtained was 0.5 m/m to 1.0 m/m. Comparative Example 3 Slop tank sludge and air floatation sludge were used as raw materials at a ratio of 2:1 (weight ratio).
The sludge mixed with A mixture of 500 g of slop tank sludge (130 g of oil), 250 g of air floatation sludge, and 23 g of hydrocarbon oil and about 2.0 times the amount of unburned carbon (same as that used in Example 1)
300 g was placed in an SPS device along with 2000 ml of water, and treated at a rotational speed of 1700 rpm for 60 minutes without adjusting the pH.
The temperature reached 100°C after 60 minutes from 25°C. The pH of the treatment solution after granulation was 4.0. Adjust the pH of the treatment solution to 11.0 with a 5% (by weight) caustic soda aqueous solution,
The ash was separated and precipitated. The liquid volume was 2600ml. 390 g of pellets and 35 g of ash were obtained. The particle size of the pellets obtained was 0.5 m/m to 1.0 m/m. Comparative Example 4 The same oil sludge as in Example 1 was used as a raw material, and the treatment was carried out in substantially the same manner as in Example 1, except that unburned carbon was not added in Comparative Example 4. The results are shown in Table 1. As shown in Comparative Example 4, granulation could not be achieved when unburned carbon was not added.

【table】

[Table] Effects of the invention (1) By using the oil contained in oil sludge as a binder for pelletizing solid carbon in unburned carbon such as EP suit, which is currently treated as industrial waste. The oil content in the oil sludge can be separated and recovered, and the ash content contained in the oil sludge and unburned carbon can be separated and recovered. (2) The solid carbon pellets mentioned above can be used as fuel and as carbonaceous industrial raw material. At the same time, useful substances (Fe, Ni, V, SiO ₂ ) contained in the ash separated and collected can also be used.

Claims (1)

[Scope of Claims] 1. Unburnt carbon generated in the combustion process of petroleum hydrocarbons is added to an aqueous slurry containing sludge discharged from the petroleum refining process to reduce the oil content in the sludge.
Add less than double the amount, use the above oil as a binder,
After granulating solid carbon containing oil by stirring at 85℃ or below without using a surfactant,
Separation of oil and ash in sludge, characterized by adjusting the pH to 7 or less and separating and collecting the aqueous phase containing ash and the solid carbon containing oil contained in the sludge and unburned carbon. How to collect. 2.Claim 1, wherein the sludge discharged from the petroleum refining process is oil sludge obtained from a slop tank or an air flotation device.
The method described in section.