US3749665A - Process for removing metals from petroleum - Google Patents

Abstract

A PROCESS FOR SEPARATING AND REMOVING METALS IN SOLUTION IN LIQUID PETROLEUM WHICH COMPRISES ESTABLISHING AN AQUEOUS FLUX SOLUTION OF WATER, CYANIDE, ZINC, LEAD ACETATE AND HYDROCHLORIC ACID; SCRUBBING THE SOLUTION AND THE PETROLEUM TOGETHER TO CAUSE THE FLUX TO COMBINE WITH THE METALS IN THE PETROLEUM AND ESTABLISH A FUSE AND, FINALLY, SEPARATING THE PETROLEUM, SOLUTION AND FUSE.

Description

United States Patent 3,749,665 PROCESS FOR REMOVING METALS FROM PETROLEUM David Bell, 6441 Cerritos Ave., Long Beach, Calif. 90805 No Drawing. Filed Apr. 10, 1972, Ser. No. 242,766 Int. (ll. (310g 29/00, 29/02 US. Cl. 208253 6 Claims ABSTRACT OF THE DISCLOSURE This invention has to do with a novel process for producing metal-free petroleum products, such as fuels, lubricants, solvents and the like.

Crude oil frequently contains substantial quantities of metallic substances, such as lead, vanadium and chrome. Such metals are found in such oil in solution or in colloidal form and are such that they cannot be readily removed from the oil or its by-products or fractions.

It is common practice to add lead to certain petroleum products such as gasoline and certain lubricating oils to alter its burning characteristics and the like. Such leaded fuels and the like, when stored in containers, conducted through pipe lines and through other handling equipment, contaminate the vessels-and equipment with lead and in such a manner that other non-leaded petroleum products subsequently deposited in the vessels or conducted in and through the pipe lines and equipment pick up the lead residue or contaminate and become ladened with appreciable quantities of lead.

Throughout the many arts where petroleum products are used or consumed, there are many instances or situations where the use of metal-free petroleum products are most desirable or are an absolute necessity for the safe, efficient and satisfactory operation of equipment. For example, in the case of jet fuel for turbine jet powered aircraft, the presence of lead and of other metals in the jet fuel will bring about serious adverse effects and the provision of metal-free fuel is most desirable.

Due to the tendency for metals in solution petroleum fuels to slow combustion and to thereby impede the complete combustion of such fuels, it has been determined that the use of leaded fuels has added greatly to pollution of the atmosphere. In efforts to reduce and/or prevent further pollution of the atmosphere, steps are presently being taken to systematically reduce the amount of leaded fuels produced and consumed and with the view of ultimately eliminating the use of such fuels.

The removal of lead and of other metals from petroleum products by known processes is so costly and complicated as to be commercially unfeasible and is, from a practical point of view, considered to be impossible.

Those processes for removing metals carried by petroleum products in solution which are known and which. have been practiced by the prior art result in considerable losses of the porducts treated by vaporization and the like and require the use of special and costly equipment and the use and expenditure of costly chemicals, supplemental'heat energy and the like. Most known processes for removing metals from petroleum products are suitable for use in small scale operations, as might be practiced in laboratories and are such that they would not be ice practical or feasible for producing large commercial volumes of metal-free petroleum products.

An object and feature of my invention is to provide an extremely simple, fast and economical process for removing metals from petroleum products which process is particularly suitable for the large scale commercial production of metal-free petroleum products.

It is an object and feature of my invention to provide a process of the character referred to which is such that it can be effectively practiced and carried out with existing storage and handling means for petroleum products found in refineries, storage tank farms and the like and which is such that it can be effectively practiced and carried out with extremely simple and inexpensive equipment and/ or apparatus in those places where appropriate apparatus and equipment does not normally exist.

It is an object and a feature of my invention to provide a process of the character referred to which involves the easy, safe and economical use of readily available, inexpensive chemicals.

A further object and feature is to provide a process of the character referred to wherein the petroleum treated is scrubbed in and with an aqueous flux solution of water, cyanide, lead acetate, zinc and hydrochloric acid whereby the metals in and carried by the petroleum combine and coalesce with the metals of the flux solution to establish a solid compound or fuse which readily precipitates from the oil and from the solution.

The foregoing and other objects and features of my invention will be fully understood from the following detailed description of the new process that I provide.

The process provided by my invention involves first, combining substantially equal portions of lead acetate and zinc (preferably powdered) in a volume of water in or to which a small volume or quantity of cyanide has been added, and last, add a sufiicient volume of hydrochloric acid to the mixture to cause the zinc and lead acetate to go into solution in and with the water, cyanide and acid whereby an aqueous flux solution is established. The volumes of cyanide and acid are small relative to the amount of Zinc and lead acetate employed.

The relative proportioning of cyanide, zinc, lead acetate and acid is not critical and is subject to considerable latitude before adverse effects are encountered.

The relative proportioning of the added materials should be established and controlled in order to effect their most economical use and to effect desired control of time required to carry out the process.

The saturation level of the additives in or with the water carrier and the volume of flux solution required for effectively carrying out my process can be varied as desired and as circumstances require.

In further carrying out of my invention, the flux solution is intimately mixed with the liquid petroleum to be treated and to effect a substantial and intimate scrubbing together of the petroleum and the flux solution.

In practice, the above noted mixing and scrubbing together of the petroleum of flux solution can be effected in storage tanks or vessels of any desired capacity and with or by means of suitable mechanical means, such as a motor driven propeller, or it can be effected in and by means of other fluid handling means, such as a centrifugal or gear type pump, the inlet side of which communicates with supplies of the petroleum and the flux solution and the outlet side of which communicates with a fluid conducting pipe extending to and communicating with a holding vessel, such as an oil field storage tank. The equipment and means to effect the last, above mentioned carrying forward of my invention commonly exists and is to be found in most petroleum refinery and storage facilities.

In further carrying forward of my new process, the mixed petroleum and flux solution is let to stand and separate in the vessel or tank in which it is mixed or in which it is deposited.

Due to the non-hydroscopic nature of the petroleum and its low specific gravity compared with the heavy metal saturated aqueous flux solution, the petroleum separates from the flux solution and floats to the top thereof when the mix of petroleum and flux solution is let to stand in the vessel in which it is deposited.

During the mixing or scrubbing of the petroleum and flux solution and during the period during which the mix is permitted to stand and separate, the colloidal metals in and carried by the petroleum coalesce with a related or relative portion of the flux solution and establish a heavy, spongy, solid fuse of the metals present, which fuse, due to the high specific gravity of the metals of which it is constituted, precipitates in and from the petroleum and thence in and through the remaining flux solution.

In practice, by using a sufliciently heavily saturated flux solution, in sufficient volume, all of the metals in the petroleum are removed or precipitated therefrom at a rate equal to or faster than the rate at which the petroleum and aqueous flux solution will separate. If a flux solution which is weak or has a low saturation level is employed, the rate at which the metals fuse and separate from the petroleum may be slowed, however, since no advantage presently appears to be attainable by use of a diluted or weak flux solution, the effects of the use thereof would only appear to be of academic interest.

In practice, the time required to effect separation and precipitation of the petroleum, flux solution and the fuse depends upon the weight, viscosity and temperature of the oil or petroleum and of the flux solution. In the case of light petroleum fractious, such as gasoline, substantially complete separation can be effected in a few minutes when small volumes of the liquids are being handled and can be effected in several hours when large volumes of liquids are being handled. In the case of heavier and more viscous petroleum fractions, or in those situations where the petroleum fractions being treated tend to emulsify with the flux solution, separation time is extended. In such cases, separation time can normally be accelerated to a material extent by the application or introduction of heat in and to the mix.

While substantially complete separation is normally effected in a rather short period of time, it is deemed advisable and prudent to let the mix or separated liquids stand an appropriate and suitable additional period of time to assure that all of the aqueous flux solution that will separate from the solution without additional work, has so separated.

Subsequent to separation of the liquids and precipitation of the fuse, the petroleum is suitably conducted away from the vessel for subsequent distribution and use.

If desired or necessary, the metal-free petroleum can be suitably dried so as to remove all trace of moisture by means of any one of those processes commonly employed to dry such products.

In practice, it would be possible to use only that quantity of flux solution necessary to react with and to effect removal and fusing of the established and known quantities of metal in the petroleum being treated, however, in such a case controls would be so diflicult to maintain as to make such a procedure undesirable. Further, and more important for the practical application and practice of the invention, sufiicient flux solution should be provided and used so that when the fuse precipitates from the petroleum and into the separated flux solution, it drops below and clear or free from the petroleum into the solution where it is kept or retained until the treated petroleum is removed. With such procedure and practice, that metal which might become free from the fuse and be picked up or reabsorbed by the petroleum, will, due

to the presence of the solution, create new fuse which will precipitate out.

After the treated petroleum is removed, the solution in the vessel can be removed for re-use and combined with additional additives and water to replenish and reconstitute it to its desired volume and concentration, if such is desired.

The fuse is then collected, removed and salvaged for its values.

In the case where the petroleum and solution are mixed together in a single vessel in which the mixing and separating process is carried out, the solution left after each batch of petroleum is treated can be left in the vessel and replenished for treatment of a next and subsequent batch of petroleum to be treated.

In the case where the liquids are mixed outside the separating vessel, and by means of a pump, the leftover flux solution can be transferred from the vessel to a solution supply tank from which it is drawn by the pump or other mixing means and in which it can be suitably replenished and/or reconstituted for treatment of a next and subsequent batch of petroleum to be treated.

In practice, it is possible to avoid practicing the above noted batch process by use of centrifugal separators, to separate the oil, flux solution and fuse. In such a case, centrifugal separators can be provided downstream of a pump type mixing means which receives, mixes and delivers the petroleum and flux solution. Through the use of such apparatus, it is possible to carry out my process in a substantially continuous manner.

In establishing my above noted flux solution it is important that the cyanide be added to the water first; that the lead acetate and zinc be added secondly and that the hydrochloric acid be added last. The speed at which the additives are added is of little importance and one can be added immediately following the other in a substantially constant flow, if the water is agitated sufficiently to effect disbursement of the materials as they are introduced into the water. In practice, when manually combining and mixing a small batch of solution, for example, one gallon of the solution, all order of cyanide and the acid disappears within a moment or two after the acid is added.

It is to be noted that the process that I provide does not involve fractioning and/ or distilling of the petroleum and is such that little or no losses of petroleum result.

Further, while the flux solution is used or consumed, the resulting fuse is salvageable and its values are not lost.

In light of the foregoing, it will be apparent that I have invented an extremely simple, practical, effective and economical process for removing metals from petroleum products.

Having described my invention, I do not wish to be limited to the specific details herein set forth, but wish to reserve to myself any modifications and variations which may appear to those skilled in the art and which fall within the scope of the following claims.

Having described my invention, I claim:

1. The process for separating and removing metals in solution in liquid petroleum which comprises first, making an aqueous flux solution of water, cyanide, Zinc, lead acetate and hydrochloric acid; next, introducing said flux solution into a volume of metal bearing petroleum to be worked upon and mixing the mixture whereby the petroleum and the solution are scrubbed one with the other and metal in the petroleum and portions of the solution combine to establish a fuse, finally separating the petroleum, aqueous flux solution and the fuse.

2. The process set forth in claim 1 wherein the separation of the petroleum, aqueous flux solution and the fuse are separated by permitting the mixture to rest whereby the relative specific gravity of the petroleum, solution and fuse causes the petroleum to separate from and float atop the solution, and the fuse to precipitate in and from the petroleum and the solution, the separated petroleum and solution are conducted away for future use and the fuse is collected for salvage.

3. The process set forth in claim 1 wherein the flux solution contains a small quantity of cyanide, substantially equal parts of zinc and lead acetate and a sufficient part of hydrochloric acid to cause the zinc and lead acetate to combine and establish the desired flux.

4. The process set forth in claim 3 wherein the separation of the petroleum, aqueous flux solution and the fuse are separated by permitting the mixture to rest whereby the relative specific gravity of the petroleum, solution and fuse causes the petroleum to separate from and float atop the solution, and the fuse to precipitate in and from the petroleum and the solution, the separated petroleum and solution are conducted away for future use and the fuse is collected for salvage.

5. The process as set forth in claim 3 wherein the cyanide is first added to the water, the zinc and lead acetate are next added to the water and the acid is last added to the water.

6. The process as set forth in claim 5 wherein the separation of the petroleum, aqueous flux solution and the fuse are separated by permitting the mixture to rest whereby the relative specific gravity of the petroleum, solution and fuse causes the petroleum to separate from and float atop the solution, and the fuse to precipitate in and from the petroleum and the solution, the separated petroleum and solution are conducted away for future use and the fuse is collected for salvage.

References Cited UNITED STATES PATENTS DELBERT E. GANTZ, Primary Examiner 20 J. M. NELSON, Assistant Examiner US. Cl. X.R. 208251, 207, 289