LT4517B - Method for fluidizing tars - Google Patents

Abstract

This invention is intended for the chemical industry. It describes a preparation method of water tar suspension-emulsion by mixing a compound that consists of: (a) viscous tar composition, consisting of tar, mineral solid substances and water, which is optional; (b) water (V); (c) surface active agent (PA), the HLB of which is at least 10 and (optional) (d) thickening polymer melting in water (TVP), the molecular mass of which is higher than 10,000. Due to the relative quantities of component parts (V), (PA) and optional (TVP), the viscosity of the compound (V) + (PA) + optional (TVP) in the best case is equal or bigger than the viscosity of the tar, and then diluting, but not necessarily, the compound with water or the watery acid solution. It is applied for the waste, having vitriolic acid, which has been formed from oil fractions during the synthesis of white olives. Besides that, this invention describes the liquefaction method of acid tar/slime, including tar/slime contacting with a vitriolic acid and cleanser. Optional for cleanser inclusion into tar/slime: a carrier may be used, thus ensuring an effective method of acid tar/mud removal from containers/tanks such as transportation containers, pipes and protection reservoirs. At best, the method also has an additional stage of vitriolic acid regeneration from liquefied tar/slime.

Description

The invention relates to the chemical industry, in particular to liquefaction of tar and sludge. In particular, the invention relates to methods for purifying tar, such as spent acid tars, from reaction vessels, process equipment, shipping containers and storage tanks using sulfuric acid, detergent and, if necessary, carrier.

The undesirable products / by-products are formed by various chemical reactions. Often these unwanted products are released into storage containers, reactors and other process equipment as highly viscous, sticky or sometimes solid substances of unknown chemical composition. They are generally attributed to tars or spam by those skilled in the art. Their physical nature is such that they are difficult to remove from containers / reactors (reactors, storage containers, transport containers, pipes, etc.) where they are formed during normal material contact processes such as pumping. They accumulate over time, reducing the capacity of the containers / vessels to carry or store the load. The tars may be formed either during a chemical reaction process, during a physical process such as distillation, and / or during storage or transport. The tars can be divided into organic, acidic, etc., depending on the physical and chemical characteristics they exhibit. Many organic materials, unlike those with a simple seal and low boiling point, occur after -pyrolysis, i.e. airless heating in highly viscous liquids known as tars.

Large amounts of tar are thus produced during industrial processes. These tars may contain residues resulting from the destructive distillation of organic material. Oil distillation produces tar residues known as bitumen or otherwise asphalt. Typically, these bitumens are high molecular weight hydrocarbons (especially 500 to 3000), most often asphaltenes (which may contain up to 25% by weight of tar), and are rich in organic carbon and hydrogen, which may also contain oxygen, sulfur or nitrogen, as well as mixtures of traces of metals, especially nickel and vanadium. Examples include viscous tar residues from the production of white oils from petroleum fractions. These viscous tars may contain acid, especially sulfuric acid.

These tars are wastes which, because of their high viscosity, are impossible or extremely difficult to pump and spray and which cannot be easily and cheaply incinerated; this is very inconvenient when it comes to regenerating the spent acids they may contain. In this way, tars must be treated as solids. Burning them to ash in a rotary kiln is expensive and can pollute the air. U.S. Pat. US 5,085,710 A method for recovering hydrocarbons and reducing the amount of sludge in storage tanks using an aqueous chemical system is one of the methods used to reduce tar / sludge contamination of containers / vessels and to recover organic matter, in this case hydrocarbon.

The present invention provides a method of treating these tars which eliminates the above disadvantages. In one embodiment of the present invention, this waste can be converted into a liquid which can be diluted with water or acid in various proportions and is stable for storage.

Sulfuric acid is used in reactions such as sulfonation, nitration, or as a catalyst for alkylation in refineries or for other purposes such as drying, tanning and the like. At the end of this process, sulfuric acid is no longer usable and must be recovered or removed. This sulfuric acid is usually. is called spent acid or spent sulfate acid. The spent acid can be regenerated into a useful sulfuric acid by several processes, including the regeneration process.

It is customary to store spent acid in storage tanks prior to on-site recovery of sulphate or · transport them elsewhere for recovery or disposal of spent acid. common modes of transportation are tank trucks, rail tankers, barges and pipelines.

Tar is found in several spent acids. When spent acid is associated with tars, they cause operational problems related to the treatment and recovery of the material during storage and transport.

When tars are formed in reactor and process equipment, such as heat exchangers, they reduce process and equipment efficiency, Tar is a heavy, viscous material that tends to stick to containers, and in some cases increases its viscosity and reacts to form in containers, solid sediment. Removal of such tar by normal pumping equipment from storage tanks, reactors or pressure transfer from tank and rail tanks is difficult due to the high viscosity of the material and in some cases due to the solid nature of the material.

It is common practice in the industry to remove such burns by physical means, cutting the opening in the container and then removing the burns physically or by vacuum. Highly viscous tars cannot be transported by conventional small (four or five inches) diameter pipes using standard vacuum pumps, most of which can create a vacuum of water column twenty-seven to twenty-eight inches high. Where material cannot be aspirated, it must be removed manually by entering the container.

Close physical contact of service personnel with tar / sludge can cause significant health, safety and environmental concerns. When tar contains volatile or hazardous materials, personnel safety and protection equipment can significantly slow down the removal process. Often all tar / sludge cannot be removed and the problem of removal or transportation remains.

The process of the present invention has the advantage that no physical penetration of the reservoir is required to remove tar / sludge. Instead, the tar is treated with sulfuric acid and a detergent which allows the tar / sludge to be mixed with sulfuric acid. The method provides a safer alternative to existing cleaning methods, especially tank cleaning, without the need for people to enter any confined or otherwise potentially hazardous area. Another advantage of this technique is the ability to regenerate tar / sludge in a form that can be easily transported, handled and pumped. In addition, the tar / slurry is provided in a suitable form for inexpensive sulfuric acid regeneration.

The present invention relates to a process for the preparation of an aqueous tar suspension emulsion, which comprises mixing a mixture (M) consisting of:

viscous tar compositions comprising (i) at least one tar having a viscosity of at least 3 Pas, preferably 30 Pa s, (ii) inorganic solids, and. if necessary, (iii) from water,

- water (V),

- at least one surfactant (PA) having an HLB (hydrophilicity / lipophilicity balance) of at least 10, for example at least 12 and, if necessary, at least one water-soluble polymer (TVP) having a molecular weight greater than 10,000, usually greater than 100000, the relative amounts of the constituents (V), (PA) and, if necessary, (TVP) are such that the viscosity of the mixture (V) + (PA) + optional (TVP) is equal to or greater than one tenth of this tar viscosity, preferably equal to or greater than the viscosity of this tar, and in that the resulting mixture is, but is not necessarily, diluted with water or at least one aqueous acidic solution.

The present invention also relates to a process for liquefying acid tars / sludges by treatment with sulfuric acid and detergent. A carrier may also be used to turn detergent into tar / sludge. This creates an efficient way of removing sulfuric acid tars / sludges from containers / vessels such as transport containers, pipes and storage tanks.

The method for removing sulfuric acid tar / sludge from containers / vessels comprises the step of contacting the tar / sludge with sulfuric acid and detergent, the step of recirculating the liquid tar / sludge to liquefaction of the total tar / sludge into the pumped medium and the liquid / tar sludge / container removal step. Ideally, the process has an additional step of burning the sludge to ash and sulfuric acid regeneration.

Unless otherwise specified, all parts or percentages are by weight or percent, respectively.

The term viscosity in this case refers to the dynamic viscosity measured at 25 ° C on a Brookfield viscometer by February 1972. AFNOR Standard NFT 76-102.

⁵ LT 4517 B

As used herein, the term "suspension-emulsion" refers to an emulsion containing inorganic solids or particles.

As used herein, the term "comprising" means that the various components may be used together. Accordingly, the terms "consisting essentially of" and "consisting of" are included within the term.

The present invention relates to a process for preparing an aqueous tar suspension-emulsion comprising mixing a mixture (M) consisting of;

- a viscous tar composition comprising (i) at least one tar having a viscosity of at least 3 Pa-s, preferably 30 Pa-s, (ii) inorganic solids and, optionally, (iii) water,

- water (V),

- at least one surfactant (PA) having an HLB (hydrophilicity / lipophilicity balance) of at least 10, for example at least 12 and, if necessary, at least one water-soluble polymer (TVP) having a molecular weight greater than 10,000, usually greater than 100000, the relative amounts of the constituents (V), (PA) and, optionally, TVP are such that the (V) + (PA) + optional (TVP) viscosity of the mixture is equal to or greater than one tenth of the viscosity of this tar. more preferably equal to or greater than the viscosity of this tar and in that the resulting mixture is, but is not necessarily, diluted with water or at least one aqueous acidic solution.

The viscous tar composition may generally comprise:

from 2 to 70% by weight, preferably from 5 to 30% by weight, for example from 10 to 25% by weight of tar;

5 to 50% by weight, preferably 10 to 45% by weight, for example up to 40% by weight of inorganic solids;

from 0 to 70% by weight, preferably from 5 to 65% by weight, for example from 30 to 65% by weight of water.

Thus, the bulk of the viscous tar composition is water. The combination of tar + inorganic solids forms a water immiscible phase. These inorganic solids are usually formed during the synthesis of tar.

Examples of inorganic solids in the viscous tar formulation to be emulsified include diatomaceous earths, quartz powder, quartz, sand, sand-gravel mixture, calcium carbonate, mica, talc, sulfur or trace metals; these inorganic solids generally have a particle size of about 0.001 to 300 µm.

It is very useful when, in addition to the viscous tar composition, the mixture (M) prepared per 100 parts by weight of tar also has:

30 to 200, preferably 40 to 120 parts by weight of water (V), and

- either from 2 to 20, preferably from 3 to 15 parts by weight of at least one surfactant (PA), or preferably from 0.5 to 10 parts by weight, preferably from 1 to 10 parts by weight of at least one surfactant. (PA) and on the other hand 0.001 to 15, preferably 0.1 to 10 parts by weight of at least one water-soluble polymer (TVP).

In the particular case, in addition to the viscous tar composition, the prepared mixture (M) may contain, per 100 parts by weight of tar:

45 to 100, for example 60 to 100 parts by weight of water (V), and either 5 to 10 parts by weight of at least one surfactant (PA), or preferably 2 to 5 parts by weight on one side at least one surfactant (PA) and on the other hand 0.5 to 5 parts by weight of at least one water-soluble polymer (TVP).

According to one alternative form of the present invention, it will be possible to use, depending on the amount of tar in the viscous tar composition, a mixture of between 2 and 70% by weight, containing 2 to 6% of surfactant (s) and 0.5 up to 2.5% water-soluble polymer (s) (TVP) in water (V) in an amount of between 1/20 and 1/4, especially between 1/15 and 1/5, for example between 1/13 and 1 / 6 the amount of viscous tar composition; this ratio will be between 1/9 and 1/7.

In addition to the viscous tar composition and water (V), the ready-to-mix mixture (M) has at least one surfactant (PA) with an HLB of at least 10, for example at least 12. The surfactant (PA) may be selected from nonionic, anionic , cationic, zwitterionic or amphoteric surfactants with an HLB of at least 10 or mixtures thereof.

Thus, it is possible to use at least one anionic surfactant having an HLB of at least 10 selected from alkali metal alkylbenzene sulfonates, alkyl sulfates, alkyl ether sulfates, alkylaryl ether sulfates, dialkyl sulfosuccinates, alkyl phosphates or ether phosphates.

It is possible to use at least one cationic surfactant having an HLB of at least 10 selected from aliphatic or aromatic fatty amines, aliphatic fatty amides or quaternary ammonium derivatives.

Ionic surfactants with an HLB of more than 20 may be suitable. It is also possible to use at least one zwitterionic or amphoteric surfactant with an HLB of at least 10 selected from betaines and their derivatives, lecithins, imidazoline derivatives , glycinates and their derivatives, amidopropionates or fatty amine oxides.

It is preferable to use at least one nonionic surfactant having an HLB of at least 10 selected, for example, from alkoxylated fatty acids, polyalkoxylated alkyl phenols, polyalkoxylated fatty alcohols, polyalkoxylated or polyglycerolated fatty amides, polyglycerolated alcohols and α-diols or ethylene oxide / ethylene oxide / ethylene oxide. copolymers, as well as alkyl glucosides, alkyl polyglucosides, sucrose ethers, sucrose esters, sucrose glycerides or sorbitol esters.

The ready-to-mix mixture (M) also contains at least one water-soluble polymer (TVP) with a molecular weight greater than 10,000 (g / mol), typically greater than 100,000 (g / mol).

This water soluble polymer (TVP) is typically dissolved in at least 50% water. Examples of suitable water-soluble polymers (TVPs) that can be used include:

- obtained by chemical synthesis, such as poly (vinyl alcohol), poly (ethylene glycol), polyvinylpyrrolidones or poly (alkali metal acrylate),

- extracted from plants and modified where appropriate, such as carrageenans, alginates, carboxylmethylcellulose, methylcellulose, hydroxypropylcellulose or hydroxyethylcellulose, and

- obtained by biosynthesis such as xanthan gum.

The surfactant (s) (PA) + water-soluble polymer (s) (TVP) system provides a highly effective stabilizing / dispersing agent for the viscous tar composition.

The relative amounts of water (V), surfactant (s) (PA) and optional water-soluble polymer (s) (TVP) are a function of the viscosity of the viscous tar composition as well as the detergent (s) (PA). and the type function of the optional water-soluble polymer (s) (TVP) (mixture). These relative amounts are such that the (V) + (PA) + optional (TVP) mixture has a viscosity equal to or greater than one tenth of the viscosity of the tar, preferably equal to or greater than the viscosity of the tar.

Typically, the amounts of surfactant (s) and water-soluble polymer (s) to be prepared are small, which is very useful, particularly from an economic point of view.

The mixing operation is carried out for a time sufficient to obtain an oil-in-water emulsion. The mixing time, which usually increases with the increase of tar content in the viscous tar composition, can only be between 0.5 and 4 hours. In addition, slow stirring is usually sufficient.

The tar emulsification operation can be performed:

adding a viscous tar composition to a mixture of water (V) + surfactant (s) (PA) + optional water-soluble polymer (s) and then stirring at a temperature between 10 and 50 ° C; or

- adding water (V) to a mixture of all or part of the viscous tar composition + surfactant (s) (PA) + optional water-soluble polymer (s) and then stirring at a temperature between 10 and 50 ° C; the remainder of the viscous tar composition, if any, is incorporated into the mixture to form an "oil-in-water" emulsion with continued mixing.

Any mixing device, in particular a slow mixing device, can be used. In this way, the mixing operation can be carried out in a mixer with a mobile part rotating at a speed of up to 2500 rpm (preferably up to 1500 rpm, more preferably at a speed of up to 500 rpm) and a mobile part for end linear velocity not exceeding 20 m / s (preferably not exceeding 5 m / s and especially good for this velocity not exceeding 2.5 m / s): preferably when the ratio is the linear velocity of the end of the mobile part / the distance between the end of the mobile part and the mixer walls - less than 50000 s ' ¹ , especially less than 2500 s' ¹ . Examples are single or multiple extruders, planetary mixers, hook mixers, slow dispersers, static mixers or blades, screw, weighted or anchor mixers.

The viscous tar composition may also comprise a hydrocarbon phase which results in the viscosity of the composition being significantly lower than or equal to the viscosity of the tar.

The monitoring of the size distribution of the particles containing the suspension-emulsions shows that the tar-suspension-emulsions obtained by the present invention are stable during storage.

The tar suspension emulsions obtained by the process of the present invention are completely diluted with water or an aqueous acidic solution (especially nitric acid waste), for example, an aqueous solution of sulfuric acid. In this way, they can be easily pumped and sprayed into a liquid incinerator.

Usually they have a viscosity of less than 80 mPas (at a water content of more than 55% by weight), in particular less than 6 mPas (at a water content of more than 65% by weight), for example a gradient of 3 s' ¹ .

The initial viscous tar composition may be the waste formed during the synthesis of white oils from petroleum fractions. The process of the present invention can be particularly advantageously applied when the starting viscous tar composition contains at least one acid, in particular sulfuric acid, as is often the case in waste oils obtained from the synthesis of white oils from petroleum fractions. It is then possible, and another object of the present invention, to recover the sulfuric acid by preparing an aqueous tar suspension emulsion, diluted with water or an aqueous sulfuric acid solution, as described above, and then burning the diluted aqueous tar suspension emulsion.

The example below illustrates, but does not limit, the invention. It is understood that various modifications and variations are possible, not shown below. Modifications which do not materially alter the process, formulation or function are considered to be within the scope of the present invention as set out below.

EXAMPLE

The following viscous tar composition (% by weight) is used:

- tar 16%

- Inorganic solids 34%

- water 50%

The inorganic solids content is determined by incineration at 950 ° C and the water content by thermogravimetric analysis at 100 ° C.

The viscosity of the tar is greater than 50 Pa s.

Prepared mixture with water (% by weight):

-1.5% Guar CSA 200/50 (water soluble polymer):

- 2% Soprophor B.S.U.® (ethoxylated tristyrylphenol with an HLB of 12.5 (nonionic surfactant));

- 2% Soprophor 3D33 (phosphated and ethoxylated tristyrylphenol with an HLB of 16 (anionic surfactant)).

During preparation of the mixture, the Guar is added to vigorously stirred water, then the detergents are added and the mixture is homogenized by gentle mixing to avoid foaming. After 1 hour, the mixture has a viscosity of about 21 Pa s.

grams of this mixture are placed in a mixer having a gate-shaped blade rotating at 500 rpm. Adding 50 grams of the above viscous tar composition to the mixer 7 times; stir until the mixture becomes homogeneous.

An aqueous tar emulsion of the following composition is then obtained (% w / w):

- tar + other organic substances 28,5%

- Inorganic solids 14.5%

- water 57.0%

This dispersion contains particles with a mean size of 4.0 µm. Monitoring of particle size distribution indicates that this aqueous suspension emulsion is stable for at least 48 hours. This dispersion is then readily diluted with waste acid containing 60% H ₂ SO _{4 in} water.

An aqueous liquid emulsion suspension is obtained, containing by weight (% by weight):

- 20.5% tar + other organic substances

- 7.0% inorganic solids

- 72.5% water + acid.

This aqueous suspension-emulsion is easily pumped and sprayed into the furnace where it is incinerated.

As mentioned earlier, the sources of tar / sludge formation are various. Acid tars / sludges are formed by reactions that use sulfuric acid, oleum (smoked sulfuric acid) and sulfur trioxide (SO ₃ ) as a reactant, medium or catalyst. A typical process for using sulfuric acid, oleum, or sulfur trioxide as a reactant is a sulfonation reaction, where the latter reacts with organic compounds to form sulfonic acids. Several examples of organic sulfonic acids are known in chemistry and industry. In many cases, excess sulfonic acid is used for sulfonation to fully utilize the sulfonizable organic compound, and sulfonic acid also acts as a solvent and reaction medium during the sulfonation process. Except for the desired product, namely sulfonic acid, the spent acid must be loaded and removed. Both during and after the sulfonation process, tar / sludge is formed during spent acid storage.

Another source of tar / sludge would be a reaction where sulfuric acid is not the primary reactant but acts as a reaction medium. A typical example of such a reaction would be a nitration reaction where nitric acid is the primary reactant and sulfuric acid is necessary to activate the reaction of the organic chemical with nitric acid. Nitration is usually performed with a so-called nitric acid, which is a mixture of nitric acid and sulfuric acid. Again, as in the case of the sulfonation, both during the nitration and after the separation of the nitro, the spent acid containing sulfuric acid and other impurities must be recovered. This is another source of tar / sludge.

In the production of high grade gasoline, sulfuric acid is used as a catalyst in a reaction called alkylation. The alkylation process involves the reaction of light alkenes containing 3, 4 and / or 5 carbon atoms with isobutane under the action of an acidic catalyst. Typically, the alkenes are propylene, 2-butene and 2-methylbutene, while the predominant products are a mixture of 2,4-dimethylpentane, 2,2,4-trimethylpentane and 2,2,5-trimethylpentane. Here, too, there are parallel side-reactions which give the products of polymerization. Once the petrol has been separated, the spent acid (commonly known as "alki spent" to denote the origin of the spent acid) is transferred to storage tanks and then transported for sulfuric acid recovery. It is known that tars are formed during the alkylation reaction and tend to accumulate in storage tanks and transport containers.

The concentration of sulfuric acid present in the tars and sludges of the above processes generally ranges from 15% to 90%, preferably from 20% to 80%. Typically, the tar / slag contains 20% to 80% sulfuric acid, 10% to 35% water, 1% to 30% carrier such as diesel, xylene or other organic chemicals, and 10% to 55% carbon, usually such as tar. The viscosity of tars / sludges can range from 2000 to over 10,000 centipoise.

The first component of the present invention is an inorganic acid. The inorganic acid used in the present invention is a strong acid such as sulfuric acid (H ₂ SO ₄ ). Any sulfuric acid commercially available is suitable for use. Usually it can be any concentration of acid - 77.7%, 93.2%, 99%, 100%, 104.5%, 109% and 114.6%. The latter three concentrations are commercially known as 20%, 40% and 65% oleum. The concentration of acid used may vary depending on the type of tar to be treated.

Concentrations below 11/7%, for example below 76% or 70%, or even lower may be used. Generally, the most suitable concentration for use in the process is 93% sulfuric acid. Phosphoric acid may be used instead of sulfuric acid. Mixtures of sulphate and phosphate acids may be used.

The second component of the invention is a surfactant, otherwise known as a "detergent". Suitable detergents include nonionic detergents, cationic detergents, amphoteric (including zwitterionic) detergents, anionic detergents and mixtures thereof. Amphoteric detergents are not suitable for use with acid tars / sludges, especially spent sulfuric acid tars / sludges. Preferably, the detergent is compatible with the acidic medium, and even more preferably, when the detergent is also stable in the non-acidic medium. Compatibility is determined by the absence of any reaction between the detergent and the acid-tar system and also by the stability of the liquid tar depending on the use of the detergent system. A certain level of reaction is allowed and it is within the scope of the practitioner to determine compatibility.

Suitable detergents are: mixed octyl / decyl alcohols, which are ethoxylated and propoxylated, nonylphenoxypoly (ethyleneoxy) ethanol, polyethoxylated tallow amine, isopropylamine alkylarylsulfonate, dinonylphenoxypoly (ethyleneoxy) ethanol, ethoxylated and propoxylated all of these components. Amphoteric detergents that may be used include: lauryl sodium diprionate, cocamidopropyl betaine, cocoamphohydroxypropyl sulfonate, and mixtures thereof. Depending on. in the composition of the tar, a suitable detergent is selected and the stability (tremor, heat release and reaction with the tar components) of the tar mixture in the acidic system is experimentally verified.

The most suitable is a detergent with a HLB of at least 10 or mixtures thereof. Ionic detergents with HLB greater than 20 are also suitable.

Useful non-ionic detergents are, for example, condensates of ethylene oxide with a hydrophobic residue having a hydrophilic / lipophilic balance (HLB) of between 8 and 16, and preferably between 10 and 12.5. Such detergents are condensation products of primary and secondary aliphatic alcohols having from 8 to 24 carbon atoms, either in straight or branched chain configuration, containing from 2 to 40, preferably from 2 to 9, moles of ethylene oxide per mole of alcohol.

Preferably, the aliphatic alcohol has between 9 and 18 carbon atoms and is ethoxylated with 3 to 12 moles of ethylene oxide per mole of aliphatic alcohol.

Suitable nonionic detergents having a HLB of at least 10 may be selected, for example, from alkoxylated fatty acids, polyalkoxylated alkyl phenols, polyalkoxylated fatty alcohols, polyalkoxylated or polyglycerolated fatty amides, polyglycerolated alcohols and α-diols or ethylene oxide / propylene oxide or also alkyl glucosides, alkyl polyglucosides, sucrose ethers, sucrose esters, sucrose glycerides or sorbitol esters.

Other suitable detergents include condensation products of alkyl phenols having from 6 to 12 carbon atoms containing from 3 to 30, preferably from 4 to 14 moles, of ethylene oxide. Such Rhone-Poulenc detergents are trademarks of Igepal CO 430, Igepal CO 530, Igepal CO 630, Igepal CO 720 and Igepal CO 730. Still other suitable nonionic detergents are described in U.S. Pat. U.S. Patent 3,976,586. An integral part of this patent is hereby incorporated by reference.

Other suitable non-ionic detergents are Rhone-Poulenc products under the trademarks Antaroz TA 4400 and Antarox BL 240.

Suitable cationic detergents include imidazoline quaternary compounds, dialkyl quaternary derivatives and benzyl quaternary derivatives as well as amino oxides, fatty imidazolines and ethoxylated amines.

Suitable cationic detergents are ethoxylated tallow amines disclosed in U.S. Pat. U.S. Pat. April 25, Rezac et al., the requisite part of which is incorporated by reference.

The propoxylated fatty amines of the ethoxylated detergents used in the present invention may be represented by the general average formula:

(CH ₂ -CH ₂ -O) _a - (CH ₂ -CH-O) _x -H. R-N 'CH ₃ (CH ₂ -CH ₂ -O) _b - (CH ₂ -CH-O) _y -H

CH ₃ where R represents hydrocarbon groups having on average between 1 and 30 carbon atoms, a and b represent 0 to 50 moles ethylene oxide (EO), x and y represent 0 to 20 moles propylene oxide (PO), a, b the sum of x and y being at least 2, preferably from 6 to 22, it is understood that a, b, x, and y express mean values, and the formula expresses mean; the various groups are arranged independently on each amino substituent chain, such as EO-PO-EO, EO-EO-EO, ΡΟ-ΡΟ-ΡΟ, EO-PO-PO, PO-EO-PO and the like.

Hydrocarbon groups may be aliphatic or aromatic, aliphatic may be linear, branched, or cyclic in nature, and may coincide or differ in the presence of fatty radicals which are composites of materials of various chain lengths. The alpha hydrocarbon radical may contain ethylene-unsaturated groups. Preferably, aliphatic groups are selected from alkyl groups and substituted alkyl groups such as long chain alkyl groups having from 6 to 30, preferably from 6 to 22 carbon atoms such as stearyl, lauryl, oleyl, cetyl, tridecyl, tertradecyl, hexadecyl, dodecyl. , octadecyl, nonadecyl, tallow, coconut, soy, myristyl and other natural fat radicals from animal, fish, vegetable and oil sources (coconut oil, palm oil, babasu oil, rapeseed oil, sunflower oil, etc.) or their substituted groups, derived from natural or synthetic sources. These chemical compounds may be illustrated by cocaine ethoxylate propoxylate, laurylamine ethoxylate propoxylate, tallow amino ethoxylate propoxylate, oleylamino ethoxylate propoxylate, stearylamine ethoxylate propoxylate, myristiamine ethoxylate propoxylate, cetylamine ethoxylate propoxylate.

Preferred cationic detergents having an HLB of at least 10 may be selected from aliphatic or aromatic fatty amines, aliphatic fatty amides or quaternary ammonium derivatives.

Commercially available cationic detergents include RHODAMEEN® PN 430, RHODAMEEN® VP-532 / SPB and RHODAMEEN® Ethoxylated Fatty Amines, ALKAOUAT® and RHODAOUAT® Cationic Quaternary, RHODAMOX® Amine Oxides, and MIRAMINE® Cationic Imidazolines and Patty Ammonium Racid, and Ine., Cranbury, New Jersey.

Examples of suitable amphoteric detergents are alkyl amphocarboxyglycinates and alkyl amphocarboxypropionates, alkyl amphodipropionates, alkyl amphodioacetates, alkyl amphoglycinates and alkyl amphopropionates in which alkyl represents an alkyl group containing 6 to 20 carbon atoms of the alkali metal amine, alkaline earth metal. Other suitable amphoteric detergents include alkyliminopropionates, alkyliminodipropionates, and alkylamphopropylsulfonates having between 12 and 18 carbon atoms; alkyl betaines and amidopropyl betaines, alkyl sulfanes and alkylamidopropyl hydroxysulfates, wherein alkyl represents an alkyl group having from 6 to 20 carbon atoms.

Particularly useful amphoteric detergents include both monocarboxylates and dicarboxylates of the formula:

θ _// CH ₂ CH ₂ OH

RC-NHCH ₂ CH - N (l) and \ ch ₂ ) _x coom

O CH ₂ CH ₂ OH _{/ {C} h ₂ ) _xC oom

RC-NCH ₂ CH -N (II) \ ch ₂ ) _x coom wherein R is an alkyl group of 6 to 20 atoms, x is 1 or 2, and M is hydrogen or sodium. Mixtures of compounds of these structures are particularly suitable.

Other formulas of the above amphoteric detergents are:

Alkyl betaines

CH ₃ r- ⁺ n-ch ₂ coom (iii);

ch ₃

Amidopropyl betaines

O

II

RO-NH-CH ₂ CH ₂ - ⁺ ch ₃ m-ch ₂ coom (IV);

ch ₃

Alkyl sulfates ch ₃

R 1 - ⁺ -CH ₂ -CH-CH ₂ SO ₃ M (V); and

CH ₃ OH

Alkylamidopropylhydroxysulfates

O CH ₃

II I

RC-NH-CH ₂ CH ₂ ⁺ N-CH ₂ -CH-CH ₂ SO ₃ M (VI);

II CH ₃ OH wherein R is an alkyl group of 6 to 20 carbon atoms and M is potassium, sodium or a monovalent cation.

Of the detergents listed above, alkylamphoxycarboxyglycinates and alkylcarboxypropionates, alkylamphodipropionates, alkylamphodiacetates, alkylamphoglycinates, alkylamphopropylsulfonates, and alkylamphopropionates, wherein alkyl represents a 6 to 20-membered alkoxy, are preferred. Even more preferred are compounds wherein the alkyl group is a coconut oil or a lauryl group, such as cocoamphiodipropionate. Such Rhone-Poulenc Cocoa Ampodipropionate Detergents are sold under the trademarks MIRANOL C2M-SF CONC. and MIRANOL FBS. Other useful commercial amphoteric detergents include:

cocoamfoacetate (trademarks MIRANOL ULTRA C-32 and MIRAPON

FA), cocoamphopropionate (trademarks MIRANOL CMSF CONC

MIRAPON FAS), cocoamphiodiacetate (trademarks MIRANOL C2M CONC. And MIRAPON

FB), lauroamphetoacetate (trademarks MIRANOL NM CONC. And MIRAPON LA), lauroamphetoacetate (trademarks MIRANOL H2M CONC. And MIRAPON LB), lauroampheto propionate (trademarks MIRANOL H2M-SF CONC. And

MIRAPON LBS), a lauric amphodiacetate derived from a mixture of lauric and myristic acids (trade name MIRANOL BM CONC.), And cocoamphopropylsulfonate (trade name MIRANOL CS CONC.) Capryamphodiacetate (trade name MIRANOL C2M CONC.) Caproamphetoacetate (trade name: SMIRC). ) caproamphiododipropionate (trademark MIRANOL S2M-SF CONC.), and stereoamphetoacetate (brand MIRANOL DM).

Also useful are betaines and amidobetaines, which are chemical compounds of the general formula:

ch ₃ ch ₃ l ₊

R 2 -CO-NH (CH ₂ ) ₃ -N-CR ³ R ⁴ -CO ₂ ch ₃ respectively, wherein R ² is C 8 -C 22 alkyl or alkenyl; R ³ is H or C 1 -C 4 alkyl; and R 4 is H or C 1 -C ₄ alkyl.

Suitable betaines include alkylbetaines such as cocodimethylcarboxymethylbetaine, lauryldimethylcarboxyethylbetaine, cetyldimethylcarboxymethylbetaine, lauryl bis- (2-hydroxyethyl) carboxymethylbetaine, stearyl-2-hydroxyethylbetaine, hydroxypropyl) alpha-carboxyethyl betaine. Also suitable are sulfobetaines which may be cocodimethylsulfopropyl betaine, stearyldimethylsulfopropyl betaine, lauryldimethylsulfoethyl betaine, lauryl bis- (2-hydroxyethyl) sulfopropyl betaine and mixtures thereof. In a particularly suitable composition, cocoamidopropyl betaine is used.

The most suitable amphoteric (including zwitterionic) detergents with HLB of at least 10 may be selected from betaines and their derivatives, juices and their derivatives, lecithins, imidazoline derivatives, glycinates and their derivatives, amidopropionates or fatty amine oxides.

Useful anionic detergents are any known hydrophobes attached to the polar solubilizing group of a carboxylate, sulfonate, sulfate, or phosphate, including salts. The salts of such detergents may include sodium, potassium, calcium, magnesium, barium, iron, ammonium and amine salts.

Examples of such anionic detergents include water-soluble alkylbenzene sulfonate salts having between 8 and 22 carbon atoms in the alkyl group, alkyl ether sulfates having between 8 and 22 carbon atoms in the alkyl group, alkali metal, ammonium and alkanolammonium salts or organic sulfonic acid reaction products. having an alkyl or alkaryl group having from 8 to 22 carbon atoms in the molecule and an ester group of a sulfonic acid or sulfuric acid.

Suitable anionic detergents having an HLB of at least 10 may be selected from alkali metal alkylbenzenesulfonates, alkylsulfates, alkyl ether sulfates, alkylaryl ether sulfates, dialkyl sulfosuccinates, alkyl phosphates or ether phosphates.

Particularly preferred are linear sulfates of sodium or potassium alkyl ethers synthesized by the sulfation of higher alcohols having from 8 to 18 carbon atoms and from 2 to 9 moles of ethylene oxide. Another anionic detergent is alkylbenzene sulfonate wherein the alkyl group has from 9 to 15 carbon atoms, preferably from 11 to 13 carbon atoms in a straight or branched chain, preferably a linear straight chain having an average alkyl group of eleven carbon atoms.

Mixtures of anionic detergents, including alkyl or alkylaryl sulfonate and sulfate detergents, may be used. Such mixtures comprise a mixture of alkylbenzene sulfonates having from 9 to 15 carbon atoms, preferably from 11 to 13 carbon atoms, alkali metal salts, preferably sodium salts, from 10 to 20 carbon atoms, preferably 12 to 18 carbon atoms, and a moderate ethoxylation. 2 to 4, an alkali metal salt, preferably sodium.

Anionic detergents which may be selected include: linear alkylbenzene sulfonates such as dodecylbenzene sulfonates, decylbenzene sulfonates, undecylbenzene sulfonates, tridecylbenzene sulfonates, nonylbenzene sulfonates and their sodium, potassium, ammonium, triethanolammonium and isopropylammonium. A suitable anionic detergent is linear isopropylamine dodecylbenzene sulfonate; one of them sold by Rhone-Poulenc Ine. is under the trademark Rhodacal® IPAM. A suitable sulfonate salt is sodium dodecylbenzene sulfonate. Such chemicals sold by Stepan Chemicals of Northfield, Illinois are under the trademark Biosoft 100. Other anionic detergents are polyethoxylated alcohol sulfates, such as the Shell Chemical Company under the trademark Neodol 25-3S. Examples of other anionic detergents are disclosed in U.S. Patent No. 3,976,586. An integral part of this patent is hereby incorporated by reference.

The optional component is a carrier to turn detergent into tar / sludge. The carrier may be aqueous or organic and is preferably selected from the group consisting of water, diesel fraction, xylene, methyl isobutyl ketone, inorganic acid (e.g. sulfuric acid) and dimethyl sulfoxide. It is used to facilitate detergent activation, mix stability and efficient removal of tar / sludge from containers. The preferred carriers are water, diesel fraction, xylene and mixtures thereof, and the diesel fraction is most preferred.

Another optional component is a suspending agent such as guar gum, a polysaccharide blend or other similarly acting polymer may be used. A suitable guar gum is Rhone-Poulenc Ine. product branded as Jaguar®.

The method of the present invention may include placing the acid and detergent in a tar / sludge container. It is advisable to mix detergent and acid before placing them in a container / container. Alternatively, add detergent premixed with the vehicle and add acid separately. When the acidity of tar / sludge prepared for liquefaction is greater than 20%, better than 30%, even better than 40% and preferably more than 50%, the acid contained in the tar is sufficient and no additional acid is required and the detergent containing tar liquefies tar and sludge and cleans the container. Liquefaction of tar / sludge means making the mixture pumpable / fluid.

Mechanical agitation and / or external recirculation may be used. However, mechanical agitation and / or external recirculation is not required. Detergent, acid and tar / slurry may be in contact and left in place until liquefied.

A second embodiment / method of the present invention is applicable to acid tars / sludges and non-acidic tars / sludges. It is recommended for use with acid tars / sludges. Unexpectedly, the present invention removes tar / sludge from containers / utensils completely, i.e. 90%, 95% at best and 100% at best.

The detergent is mixed with an acid, preferably sulfuric acid, in a temperature range of 60 ° F (16 ° C) to 150 ° F (66 ° C), preferably 75 ° F (24 ° C) to 100 ° F (38 ° C). ). Very high temperatures are not used as they can cause carbonisation of solids. The highest recommended temperatures, which do not cause any significant charring, are 150 ° F (66 ° C).

The method of complete cleaning of storage tanks and transport containers from sludge and tar in accordance with the present invention involves contacting the tar / sludge with

75-90% concentration with sulfuric acid at 60 ° F to 150 ° F;

incorporating the detergent into the tar / sludge / sulfuric acid mixture at a concentration of from 0.2 to 7.5% by weight of the final mixture, and, but not necessarily, contacting the tar / sludge with diesel fraction, xylene, water or other carrier. Further, the present invention relates to a method wherein the contacting is performed by mechanical agitation and / or external recirculation to the tank, or by introducing an acid / detergent mixture into the suction side of the pump and recirculating through the tanks / transport containers through nozzles or openings at the top or sides.

The following examples are intended to better illustrate the invention without, however, limiting it. They are intended only to illustrate the invention, and it is to be understood that modifications and variations are not contemplated herein. Such modifications, which do not substantially alter the process, formulations, or function, are to be considered within the spirit and scope of the invention as set out below.

EXAMPLE

In this example, the tar was removed from the rail tank full of tar. Removing the tar manually by cutting the opening is too expensive, and another option would be to remove it from the tank into the ground storage. The spent acid tar mentioned in the present invention was formed in a plant which produces specialty chemicals and uses sulfuric acid in the sulfonation process. The process also uses xylene, among other organic materials. At the end of the process, the spent acid is transferred to a rail tank for transport to a sulfuric acid recovery unit. The rail tank was inspected and three layers of material were found. The tar is distributed between three layers. During the laboratory analysis of the contents of the railway tank, a flammable supernatant containing xylene was found and the tar layer, which is the dominant layer, was difficult to remove. Based on this assessment, the rail tank is cleaned as follows: a batch process is used. Two concentrations of sulfuric acid are used. Commercially available 93% sulfuric acid is used for blending with tar and 78% sulfuric acid is used to flush the transmission line. RHODACAL IPAM Anionic Detergent (supplied by Rhone-Poulenc Ine., Cranbury, New Jersey) is used for tar blending. 66 parts of 93% sulfuric acid are placed in a batch mixing tank with a stirrer. This is followed by the introduction of 0.8 parts of RHODACAL IPAM (linear isopropylamine dodecylbenzene sulfonate). Then, 100 parts of the tar-containing layer are transferred from the rail tank at a nitrogen pressure of about 50 psig to a mixing tank containing 93% concentration of sulfuric acid and detergent. The rail tank is then rinsed with 35 parts of 78% sulfuric acid and the resulting solution is also transferred to a stirred nitrogen tank. This flushes the transmission lines. The contents of the tank are stirred for about one hour. The contents of the reservoir are then transferred to a rail tank for transport to a sulfuric acid recovery unit. The resulting liquefied spent acid is stable and the tar is not separated during subsequent transport. The rail tank is completely cleaned.

EXAMPLE

In the manner described in this example, the tar is removed from a storage tank of 25,000 gallons (14 feet wide by 22 feet high), which is used to store sulfuric acid used up in the alcohol process in a chemical production facility. This unit generates some tar during the process. This tar, together with the spent acid, is stored in a storage tank. More than 18 months later, tar builds up at the touch point of the tank. The method of the present invention is used to clean and inspect the reservoir, since inspection of the reservoir is meaningless if its surface is tar-coated. Take the tar sample and analyze it. The reservoir contains about 37% sulfuric acid, about 20% water and the remainder is an unknown carbon composition. The viscosity is over 10,000 centipoise as measured by a Brookfield viscometer. The free acid in the reservoir is sucked out of the reservoir, leaving tar and a small amount of free acid in the reservoir. Due to the origin of the tar and the fact that it contains 37% sulfuric acid, no additional sulfuric acid is required '. The diesel fraction is used as a carrier to facilitate the mixing of tar with detergent. Accordingly, about 5 parts of the diesel fraction are mixed in a mixing tank with about 1 part dinonylphenoxy (ethyleneoxy) ethanol detergent (commercially known as IGEPAL CO 630 supplied by Rhone-Poulenc Ine.). The diesel fraction-detergent mixture is introduced into the tank interior via a recirculation pump. The quantities used consist of 94 parts tar, 5 parts diesel fraction and 1 part detergent. The liquid from the reservoir is recirculated to the reservoir. This recirculation process is continued until the viscosity is less than 800 centipoise. The contents of the tank are then transferred to the road tanker. Inspection of the reservoir revealed that the tar was completely removed.

EXAMPLE

In the manner described in this example, the tar resulting from a similar alcoholic process as described in Example 2 is removed from the rail tank. In this example, tar removal is done without mechanical agitation or external recirculation. The removal is accomplished by storing the tar along with the detergent carrier mixture. There is a significant flotation of the tar layer on the surface of the spent acid. Initially, free acid is removed from the rail tank by air pressure. About 750 gallons of diesel fraction, three 55 gallon drums of polyethoxylated tall amine detergent (commercially known as RHODAMEEN PN 430 supplied by Rhone-Poulenc Ine.) Are added and mixed. Half of the diesel fraction - detergent mixture is transferred to the tar tank. Thereafter, 93% sulfuric acid is added to the rail tank. All content is left to stand for 24 hours. During this time, the tar liquefies and the charge is pumped into a storage tank for sulfuric acid regeneration. The remainder of the diesel fraction-detergent mixture is transferred to the rail tank, where there is still insoluble matter, with the addition of more 93% sulfuric acid. The contents of the rail tank are left to stand for another 24 hours and then pumped into a storage tank. During this process, the tar is completely dissolved / decomposed into pumped particles and removed from the rail tank.

EXAMPLE

227,000 gallons capacity · The storage tank has accumulated a nearly 10-foot layer of tar over seven months on the surface of spent sulfuric acid stored in the tank. Accordingly, the free acid in the lower layer is drained from the reservoir and transferred to another reservoir for regeneration. This lowers the tar layer to the bottom of the tank. 93% sulfuric acid is introduced into the tank from above using a centrifugal pump in the ratio: two parts 93% sulfuric acid per part tar. The isopropylamine alkylarylsulfonate detergent (RHODACAL IPAM, supplied by Rhoe-Poulenc Ine.) Is introduced into the suction side of the pump and further into the reservoir above the tar-sulfonic acid in the ratio: 0.013 parts detergent to one part of the tar. Recirculation is continued for approximately 48 hours, during which period the liquefaction of the tar in the bed is periodically checked by inserting a rod from the top of the tank. When tar liquefaction is determined, the contents of the tank are transferred to a storage tank for sulfuric acid regeneration. Upon inspection, the tank was found to be clean and free of tar.

Claims (46)

DEFINITION OF INVENTION A process for the preparation of an aqueous tar suspension emulsion, characterized in that it comprises a mixture (M) consisting of: - a viscous tar composition comprising at least one tar, an inorganic solid and, optionally, water, - water (V), - at least one surfactant (PA) having an HLB of at least 10 and optionally at least one water-soluble polymer (TVP) having a molecular weight greater than 10,000, containing the constituents (V), (PA) and optional component The relative amounts of (TVP) are such that the (V) + (PA) + optional (TVP) viscosity of the mixture is equal to or greater than one tenth of the viscosity of this tar, during the blending step. 2. A process according to claim 1, further comprising the step of diluting the resulting mixture with water or at least one aqueous acid solution. 3. A process according to claim 1, wherein the relative amounts of the constituents (V), (PA), and optional component (TVP) are such that the mixture has a viscosity of (V) + (PA) + optional (TVP) or higher than the viscosity of this tar. 4. The method of claim 3, wherein said viscous tar composition comprises: 2 to 70% by weight of tar; 5 to 50% by weight of inorganic solids; and 0 to 70% by weight of water. 5. A process according to claim 1, wherein said tar has a viscosity of at least 3 Pa s. 6. A process according to claim 1, wherein the mixture (M) further comprises (100 parts by weight of tar) in addition to the viscous tar composition: 30 to 200 parts by weight of water (V), and 2 to 20 parts by weight of a mixture of at least one surfactant (PA) or 0.5 to 10 parts by weight of at least one surfactant (PA) and from 0.001 to 15 parts by weight of at least one water-soluble polymer (TVP). 7. The method of claim 1, wherein the surfactant (PA) is selected from the group consisting of: nonionic, anionic, cationic, zwitterionic, or amphoteric surfactant (s) and mixtures thereof having an HLB level of at least 10. 8. The process of claim 1, wherein the water-soluble polymer (TVP) has a water solubility of at least 50% and may be selected from the group consisting of: polyvinyl alcohol, poly (ethylene glycol), polyvinylpyrrolidone , poly (alkali metal acrylates), carrageenans, alginates, xanthan gum, carboxymethylcelluloses, methylcelluloses, hydroxypropylcelluloses or hydroxyethylcelluloses and mixtures thereof. 9. The process of claim 1, wherein mixing is accomplished by introducing a viscous tar composition into a mixture of-water (V) + surfactant (PA) + optional water-soluble polymer (TVP), and then mixing from about 10 to about At 50 ° C. 10. The method of claim 9, further comprising the step of diluting with water or at least one aqueous acid solution. 11. A process according to claim 1, wherein the mixing is carried out by adding water (V) to a mixture of all or part of the viscous tar composition + surfactant (PA) + optional water-soluble polymer (TVP), followed by mixing from about 10 to 50 ° C, and the remaining amount of the viscous tar composition, if any, is introduced into the mixture to form an oil-in-water emulsion with continued mixing. 12. The method of claim 11, further comprising the step of diluting with water or at least one aqueous acid solution. 13. The method of claim 1, wherein the mixing operation is performed in a mixer having a mixer having a mobile part rotating at a speed of up to 2500 rpm at a linear mobile end speed of up to 20 m / s. 14. The method of claim 13, wherein the ratio of the linear velocity of the end of the mobile portion to the distance between the end of the mobile portion and the wall of the mixer is less than 50,000 s' ¹ . 15. The method of claim 1, wherein the mixing operation is performed in a mixer having a mixer having a mobile end rotating at a speed of up to 1500 rpm at a linear mobile end speed of up to 5 m / s. 16. The method of claim 15, wherein the ratio of the linear speed of the end of the mobile portion to the distance between the end of the mobile portion and the wall of the mixer is less than 10,000 s' ¹ . 17. The method of claim 1, wherein the mixing operation is. carried out in a mixer having a stirrer whose mobile part rotates at a speed of not more than 500 rpm at a linear mobile end speed of not more than 2.5 m / s. 18. The method of claim 17, wherein the ratio of the linear speed of the end of the mobile portion to the distance between the end of the mobile portion and the wall of the mixer is less than 2500 s' ¹ . 19. A process according to claim 17, wherein the viscous tar composition is a residue formed during the synthesis of white oils from petroleum fractions. 20. The method of claim 1, wherein the viscous tar composition comprises at least one acid. 21. The process of claim 20, wherein the acid is sulfuric acid. 22. A process for the regeneration of sulfuric acid in a viscous tar composition, comprising the step of producing, as described in claim 1, an aqueous tar suspension emulsion diluted with water or an aqueous sulfuric acid solution, and then burning said dilute aqueous tar suspension emulsion. 23. A process for liquefying tar / sludge or removing tar / sludge from containers / vessels, such as transport containers, reactors, pipes and storage containers, comprising the step of contacting the tar / sludge with inorganic acid and detergent. 24. The method of claim 23, wherein the inorganic acid is selected from the group consisting of sulfuric acid, phosphate acid, or mixtures thereof. 25. The method of claim 24, wherein the inorganic acid is sulfuric acid. 26. The method of claim 23, wherein said detergent is selected from the group consisting of nonionic detergents, cationic detergents, amphoteric detergents, anionic detergents, and mixtures thereof. 27. The method of claim 23, wherein the tar / slurry has an acid. 28. The method of claim 27, wherein said detergent is selected from the group consisting of nonionic detergents, cationic detergents, anionic detergents, and mixtures thereof. 29. The method of claim 23, wherein the inorganic acid and detergent are premixed prior to contact with the tar / sludge. 30. The method of claim 23, wherein the detergent is premixed with a carrier prior to contact with the tar / sludge. 31. The method of claim 30, wherein the carrier is selected from the group consisting of water, diesel fraction, xylene, methyl isobutyl ketone, isopropyl alcohol, dimethyl sulfoxide, sulfuric acid, and mixtures thereof. 32. The method of claim 27, wherein the tar / slurry comprises sulfuric acid. 33. The method of claim 25, wherein the concentration of said sulfuric acid is greater than 75%. 34. The method of claim 23, further comprising the step of recirculating the liquefied tar / sludge to a complete medium for converting the tar / sludge into the pumped medium and removing the tar / sludge. 35. The method of claim 25, further comprising the step of regenerating said sulfuric acid. 36. The method of claim 32, further comprising the step of regenerating said sulfuric acid. 37. A method comprising the step of contacting the tar / sludge with detergent and carrier. 38. The method of claim 37, wherein the tar / slurry contains from 20 to 80% sulfuric acid. 39. A process comprising the steps of contacting the tar / sludge with detergent and carrier, which results in almost complete removal of the tar / sludge containing more than 20% acid. 40. The method of claim 39, further comprising the step of mechanical mixing or external recirculation. 41. A process comprising the steps of contacting tar / sludge with 7590% acid at 60-150 ° F and detergent at a concentration of 0.2 to 7.5% by weight of the final mixture. 42. The method of claim 23, wherein said detergent is selected from the group consisting of mixed octyl / decyl alcohols that are ethoxylated and propoxylated, nonylphenoxypoly (ethyleneoxy) ethanol, polyethoxylated tallow amino, isopropylamine alkylsulfonate, dinonylanyl, and propoxylated tallow amine mixtures and mixtures thereof. 43. The method of claim 23, wherein said detergent is selected from the group consisting of cationic detergents. 44. The method of claim 43, wherein said cationic detergent is selected from the group consisting of fatty aminoethoxylate detergents having the general mean formula: (CH ₂ -CH ₂ -O) _a - (CH ₂ -CH-O) _x -H R N CH 3 (CH ₂ -CH ₂ -O) _b - (CH ₂ -CH-O) _y -H CH ₃ where R represents hydrocarbon groups having an average of 1 to 30 carbon atoms, a + b represents 0 to 50 moles ethylene oxide (EO), x and y represents 0 to 20 moles propylene oxide (PO), a, b , the sum of x and y is independent and expresses mean values, and the sum of a, b, x and y is at least 2. 45. The method of claim 26, wherein said detergent is selected from the group consisting of: (i) Alkali metal alkyl benzene sulphonates, alkyl sulphates, alkyl ether sulphates, alkyl aryl ether sulphates, dialkyl sulphosuccinates, alkyl phosphates and ether phosphates: (ii) aliphatic or aromatic fatty amines, aliphatic fatty amides and quaternary ammonium derivatives; (iii) betaines and their derivatives, sulfates and their derivatives, lecithins, imidazoline derivatives, glycinates and their derivatives, amidopropionates and fatty amine oxides; (iv) alkoxylated fatty acids, polyalkoxylated alkyl phenols, polyalkoxylated fatty alcohols, polyalkoxylated or polyglycerolated fatty amides, polyglycerolated alcohols and block copolymers of ethylene oxide / propylene oxide, glycerides of alkyl glucosides, esters of alkyl polysaccharides, ; and (v) mixtures thereof. 46. The method of claim 26, wherein said detergent has an HLB value of at least 10.