KR0128217B1 - Method for separating water from waste oil using chemical additive - Google Patents

Abstract

Process for separating oil and water consists of i)filtrating waste oil with a filter of hole size of 500-1,000 microns, ii)adding the mixture of an aromatic light distillate and distillate with 1,000-3,000 ppm of aromatic petroleum hydrocarbon additives which is the mixture of 5-10 wt.% of C4-C8 alcohol, 1-10 wt.% of xylene, 1-10 wt.% of ethylenebenzene and 1-10 wt.% of naphthalene, iii)maintaining at a stirring speed of 150-300 rpm at 50-80 deg.C for 60-80 hr.

Description

Oily Water Separation Method Using Chemical Additives

1 is a process schematic diagram of an oil-water separation method using a chemical additive.

The present invention relates to a method for separating an emulsion (emulsifiable) moisture layer present in waste lubricating oil (hereinafter referred to as "waste oil") stored in a storage tank.

In more detail, the present invention is a pure oil layer by a certain amount of aromatic hydrocarbon-based chemical additives to the waste oil to remove the dispersed foreign substances through a simple filtration process, and then suspended in a storage tank for a certain period of time to maintain a temperature and a stirring speed within a pure oil layer And a method for separating the emulsifying water layer.

In general, waste oil generated after being used in automobile internal combustion engines is recovered through lubricating oil exchangers and collectors, temporarily stored in storage tanks, and then processed and recycled. During the treatment process, the water contained in the waste oil should be removed. The amount of water in the waste oil collected and stored is about 5-10% by weight, although it varies greatly depending on the collection path and storage method. This water is converted into an emulsified water layer stabilized by a chemical additive of a surfactant component in waste oil or a disperse foreign matter and light oil obtained from combustion and degradation products of hydrocarbons. However, such an emulsified aqueous layer cannot be separated from the pure oil layer simply by being left in the storage tank for a certain period of time. Rather, the range of the emulsified aqueous layer is greatly increased by the storage method or the external environment. The clear distinction of oil can be eliminated, which can result in severe degradation of the water removal rate, which can seriously impair subsequent waste oil treatment.

In particular, when refined waste oil containing a large amount of emulsified water layer by general distillation method, due to the volume expansion of vaporized water, which is much larger than that of hydrocarbons based on the same liquid molar volume, within the boiling point where the liquid phase changes to the gas phase, It will have a huge impact on. Furthermore, such waste oil was filed by the applicant on the date of 92.9.18 (Application No. 92-17034) under the name of "Method for separating low-pollution fuel oil and asphalt from waste oil". 5. In case of distillation under reduced pressure according to the method disclosed in 94-3998 dated 10, the sudden volume expansion of water also damages the filling material inside the distillation column and causes fluctuations in operating pressure, thereby reducing the overall operating efficiency. In addition, there is a problem in that the high boiling point of the hydrocarbon molecules together with the vaporized water to reduce the separation efficiency of the entire mixture.

In addition, conventional techniques for removing emulsifying water and other contaminants in advance in waste oil treatment and refining processes generally include two types of treatment processes. First, simple distillation at an appropriate temperature of 150 ° C. or lower By acid / clay process. KTl of the Netherlands. Mohawk in Canada and LUWA process in Switzerland. However, while the method of the present invention consumes about 800 million won per 300 barrels / day, the above methods require about 2.5 billion won in terms of facility investment cost, which is not only expensive but also does not have sufficient theoretical singularity or reflux device. In the case of the removal of impurities in the waste oil, in particular ionic metal complex chloride, the separation efficiency is very low compared to the present invention. Secondly, as a method of adding a chemical post-treatment process using a solvent in the distillation process, the French IFP or the US BERC process has been developed and used. However, most of them use solvent aftertreatment process, which requires high investment and operation cost, to produce high value lubricant base oil, unlike domestic situation that produces fuel oil by refining waste oil. Inconsistent with the situation, there is a high possibility of secondary environmental pollution by the organic solvents used.

Accordingly, an object of the present invention is to significantly improve the operational barriers and separation efficiency of the waste oil treatment process according to the above-mentioned Patent Publication No. 94-3998 by separating and removing the foreign matter dispersed in the waste oil and the emulsified water layer and water in advance. The present invention provides an oil separation method that is equal to or better than that in terms of economic efficiency and separation efficiency.

Separation method of the present invention for achieving the above object is a waste oil is mixed with a certain ratio with the aromatic hydrocarbon-based chemical additive for oil and water separation through a simple filtration process, the mixed oil in a storage tank in a range of temperature and stirring speed It consists of separating into a pure oil layer and an emulsified water layer by holding it for a certain period of time. When water is introduced into the waste oil, a stabilized emulsion layer (oil wrapped in water) is formed by chemical components acting as surfactants in the waste oil, that is, additives, combustion products, and hydrocarbons deterioration. Simple administration of chemical additives here, even if the emulsion breaks, the water particles released at that time can not move freely due to the high viscosity of the waste oil. Therefore, expansion of the water layer through aggregation of water particles and oil / water separation due to specific gravity difference cannot be expected, and chemical additives cannot exert sufficient effects.

Therefore, in the present invention, the solid impurities, which act as emulsifiers in the waste oil, were firstly removed through a filtration device, and then, chemical additives were administered to uniformly disperse the same through a line mixer to maximize the effect. In addition, by heating in the storage tank to lower the viscosity of the waste oil to agglomerate between the free water particles, and then introduced a stirring device to apply an external pressure to the interfacial membrane that can be more solid. To describe the present invention in more detail, first, waste oil recovered through a lubricating oil exchanger and a collector is filtered through a 500-1000 μm Coarse Filter to remove solid impurities and dispersed foreign substances, and then aromatic petroleum hydrocarbon-based chemicals. The additive is mixed about 1000-3000ppm, and it is maintained in the storage tank for about 60-80hr at a temperature of about 50-80 ° C and a stirring speed of about 150-300rpm to perform oil and water separation. The aromatic petroleum hydrocarbon-based chemical additive is about 5-10% by weight of alcohols having about 4-8 carbon atoms, about 1-10% by weight of xylene, about 1-10% by weight of ethylbenzene, and naphthalene in a mixture of aromatic hard oil and distilled oil. About 1-10% by weight. As a representative example, 93BH04 of CHEMLINK, USA, which contains about 80% by weight of Petroleum Distillates, about 10% by weight of xylene, about 5% by weight of butanol, about 3% by weight of naphthalene, and about 2% by weight of ethylbenzene. Can be mentioned. The aromatic petroleum hydrocarbon-based chemical additive is mixed at a constant mixing ratio, preferably at about 1000-3000 ppm, and maintained at a temperature of about 50-80 ° C. and a stirring speed of about 150-300 rpm in a storage tank for about 60-80 hr. It is designed so that it is always separated and maintained at about 80-90% by volume pure oil layer and 10-20% by volume emulsified water layer, preferably about 87% by volume pure oil layer and 13% by volume emulsified water layer. It is done.

Hereinafter, preferred embodiments of the present invention are described. However, the following examples are only for demonstrating the effects of the present invention, and the present invention is not limited to the following examples.

Example 1

(Water separation effect experiment after filtration)

If proper filtration process is not carried out, a large amount of highly stabilized emulsifiable moisture layer is formed due to dispersed foreign matter or suspended matter in the waste oil. In the example, some of the waste oils from the bus, LPG taxi, and car centers were mixed with a volume ratio of 6: 3: 1, respectively, and some of them were filtered using a coarse filter having a pore size of 500 μm. . In each of the waste oils, US CHEMLINK's 93BH04 chemical additive, that is, an additive containing 80% by weight of petroleum distillate, about 10% by weight of xylene, about 5% by weight of butanol, about 3% by weight of naphthalene and about 2% by weight of ethylbenzene The mixture was maintained at about 1,000 ppm until it stabilized at a temperature of 60 ° C. and a stirring speed of 200 rpm.

[Table 1] Evaluation of Water Separation Performance Before and After Dispersion of Debris (Unit: Volume%)

Each result obtained in the above example is shown in Table 1 through which the oil and water separation method performed after filtration was found to greatly improve the water separation effect due to a significant decrease in the emulsified water layer remaining in the waste oil.

Example 2

(Water separation effect experiment by temperature)

In Example 2, the waste oil, which had undergone the filtration process of Example 1, was given several temperature ranges in the storage tank in order to obtain a better oil / water separation effect. First, after filtration, the waste oil mixed with 2000ppm of 93BH04 chemical additive from CHEMLINK of USA was stirred at 200rpm and the internal temperature of the storage tank was changed to 30, 45, 60, and 75 ℃, respectively. The results were then measured and shown in Table 2 below.

[Table 2] Water Separation Result by Temperature Change in Storage Tank (Unit: Volume%)

As shown in Table 2, the higher the temperature of the sample, the lower the viscosity of the waste oil, the better the diffusion effect of the oil-and-water separator used as a chemical additive. Showed excellent results. From the above results, it was found that the operating temperature in the storage tank is effectively maintained at about 50-80 ° C, preferably about 60 ° C, in consideration of the actual process operation.

Example 3

(Water separation effect experiment by stirring and leaving time)

The water and oil phase interface in the emulsified water layer present in the waste oil is very stabilized due to lubricating oil additives having surface-active components in the waste oil or dispersed foreign matters such as hydrocarbon combustion and deterioration products and light oils, and thus, are applied to other types of emulsified moisture. It's pretty solid. In the case of the emulsified moisture layer having such an interfacial membrane, the energy barrier for destroying the emulsion phase becomes high, and as a result, it requires mechanical disturbance (external pressure) as well as efforts to increase the concentration of the chemical additive or raise the temperature. It may be required. In the present Example 3, the mechanical separation effect of the filtration and the addition of 93BH04 chemical additives of CHEMLINK Co., Ltd. in the US and then left alone over time in the storage tank and stirred at 200rpm for each The degree of oil separation was examined.

In addition, the temperature of the storage tank was maintained at 60 ° C. in order to find an appropriate time for oil separation, and the effects of oil separation according to several times were evaluated and the results are shown in Table 3.

[Table 3] Result of water separation according to stirring and leaving time (unit: volume%)

In Example 3, it was confirmed that the water separation effect of the agitation was superior to the case in which it was simply left in the storage tank. Since the purpose of agitation in the storage tank is to destroy the interfacial membrane of the emulsion suspended in the waste oil, the influence of external pressure due to agitation should be limited to the bottom emulsion layer in the tank. Therefore, the optimum stirring speed measured through various examples was found to be about 150-300rpm is preferred.

In the case of the standing time, it was found that the interface between the oil layer and the emulsified layer was relatively stabilized and reached 60 hours, and that it was desirable to settle for about 60-80 hours in the storage tank as no significant change was observed over 80 hours. .

Example 4

(Determination of Chemical Additive Addition)

Based on the optimum operating conditions selected through the above examples, that is, left for 3 days at a temperature of 60 ° C. and a stirring speed of 200 rpm, in Example 4, 80% by weight of petroleum distillate and 10% by weight of xylene and butanol When the addition concentrations of 93BH04 chemical additives of CHEMLINK, USA, in which 5% by weight, 3% by weight of naphthalene and 2% by weight of ethylbenzene were varied, the water separation results (Table 4) were examined.

As shown in Table 4, when the dosage of the chemical additive is in the range of about 1000-3000ppm, in any case, the leaving time was about 60-80 hours, which showed a constant oil / water separation effect. That is, when the concentration is 1000ppm or less, a long time is required for the water separation, and the effect is insignificant under the given conditions. Above 1000ppm, the oil-water separation tends to show no significant improvement even if the additive concentration is increased, so about 2000ppm is sufficient even in consideration of changes in other external environments during actual process input.

[Table 4] Determination experiment of aromatic hydrocarbon additive addition amount (unit: volume%)

Through the present invention, water and contaminants contained in the waste oil are subjected to a simple filtration process without undergoing a special process such as distillation or solvent treatment. Equal or superior in terms of economics or separation efficiency. In the case of the existing domestic refining companies, the waste oil treatment method is simply heated by the three-phase method or ion purification method, which is relatively inexpensive, and evaporates the water in the oil fraction. Separation will be needed further, so that vacuum distillation purification can be effectively put to practical use.

That is, compared to the simple distillation method (dehydrator), the present invention reduces the investment cost in terms of economics, and in terms of treatment process, by introducing solid impurities and water-soluble contaminants in the waste oil into the water layer at the bottom of the storage tank, Compared with the remaining ones, the separation efficiency of contaminants is improved and the burden of the vacuum distillation process itself is reduced. In addition, there is no source of secondary waste because no chemical solvents are used.

As a result, a large amount of low pollution high quality fuel oil is produced through the water treatment process of the present invention, thereby generating enormous added value according to the yield improvement, and thus the economic and environmental effects are great.

Claims (8)

After the recovered waste oil was filtered, 5-10% by weight of alcohols having 4 to 8 carbon atoms, 1-10% by weight of xylene, 1-10% by weight of ethylbenzene, and 1-10% of naphthalene were added to the mixture of aromatic light oil and distilled oil. By mixing the aromatic petroleum hydrocarbon-based chemical additives in weight percent at about 1000-3000ppm, and maintaining them at a temperature of about 50-80 ℃, a stirring speed of about 150-300rpm and staying in the storage tank for about 60-80hr, Oil-water separation method for separating oil layer and emulsified water layer. The method of claim 1, wherein the aromatic petroleum hydrocarbon-based chemical additive comprises about 80% by weight of petroleum distillate, about 10% by weight of xylene, about 5% by weight of butanol, about 3% by weight of naphthalene and about 2% by weight of ethylbenzene. Oil-water separation method using 93BH04 of CHEMLINK of USA. 2. The method of claim 1, wherein the filtration process uses a coarse filter having a pore size of about 500-1,000 μm. 2. The method of claim 1, wherein the compounding concentration of the chemical additive is about 2000 ppm. The method of claim 1, wherein the temperature in the storage tank is maintained at about 60 ℃. The method of claim 1, wherein the residence time in the storage tank is about 60 hours. 2. The method of claim 1, wherein the constant ratio is about 80-90% by volume of the pure oil layer and 10-20% of the emulsified water layer. 8. The method of claim 7, wherein the pure oil layer is about 87% by volume and the emulsified water layer is always separated and maintained at about 13% by volume.