A non-hazardous cleaning solution/process has been developed to remove oxide residues from the surface of blackened needles. Low concentrations of citric acid solution are mixed with blackened needles and treated in an ultrasonic tank for short period of time (<5 minutes). The oxide residues are substantially removed.

Process and device for cooling a steel strip (1) running through the cooling section (2) of a continuous line, whereby cooling is achieved by projecting the strip with an aqueous solution of formic acid with a concentration of formic acid between 0.1% and 6%, and preferably between 0.5% and 2%.

The invention includes a method of reducing a need to re-acidize a hydrocarbon-containing formation. The method comprises providing a composition a HCl and lysine mixture and water wherein a molar ratio between the HCl and the lysine mixture ranges between 3:1 and 12.5:1, and the composition has an initial pH of less than 1; injecting the composition into the formation; allowing a sufficient time for the composition to become a spent acid composition and to subsequently create wormholes in the formation by dissolving calcium carbonate in the formation; maintaining the dissolved calcium carbonate in suspension in the spent acid composition to prevent reprecipitation of the calcium carbonate into the wormholes; removing the spent acid composition containing the dissolved calcium carbonate from the formation; and wherein a pH of the spent acid composition ranges between 4 and 6.

An aqueous synthetic acid composition is provided for use in oil industry activities. The composition comprises: lysine and hydrogen chloride in a molar ratio ranging from 1:3 to 1:12.5, preferably from more than 1:5 to 1:8.5. The composition may further comprise a metal iodide or iodate and an alcohol or derivative thereof. The composition demonstrates advantageous properties for synthetic acids at temperatures above 90° C. The composition is useful in various oil and gas industry operations. Preferred embodiments of the composition provide substantial advantages in matrix acidizing by increasing the effectiveness of wormholing.

A film-forming apparatus is connected to a carbon steel cleanup system pipe of a BWR plant. Formic acid and hydrogen peroxide are injected into the circulation pipe of the film-forming apparatus. An iron elution accelerator aqueous solution containing 3000 ppm of formic acid and 1500 ppm of hydrogen peroxide is brought into contact with the inner surface of the cleanup system pipe, and Fe2+ is eluted from the cleanup system pipe by formic acid, and hydroxyl radicals generated from hydrogen peroxide. The film-forming aqueous solution produced from the iron elution accelerator aqueous solution by injecting the nickel formate aqueous solution is brought into contact with the inner surface of the cleanup system pipe, and the Ni ions incorporated into the inner surface by the substitution reaction are reduced by the electrons generated at the time of elution of Fe2+ to form a Ni metal film on the inner surface thereof.

A method for pickling a steel plate having a first steel plate portion and a second steel plate portion which is connected to a tail end of the first steel plate portion and which requires a longer time for pickling than the first steel plate portion when pickled under the same condition includes: a step of pickling the steel plate by immersing the steel plate in an acid solution in at least one pickling tank while conveying the steel plate; a step of circulating the acid solution, through a circulation line connected to any of the at least one pickling tank, between the pickling tank and an oxidizing device disposed in the circulation line; a step of oxidizing Fe.sup.2+ in the acid solution to Fe.sup.3+ by the oxidizing device using a gaseous oxidant; and a feeding start step of, upon switching from pickling of the first steel plate portion to pickling of the second steel plate portion, starting feeding of a liquid oxidant for oxidizing Fe.sup.2+ in the acid solution to Fe.sup.3+ to any of the at least one pickling tank or to the circulation line.

An aqueous synthetic acid composition is provided for use in oil industry activities The composition comprises: lysine and hydrogen chloride in a molar ratio ranging from 1:3 to 1:12.5, preferably from more than 1:5 to 1:8.5 The composition may further comprise a metal iodide or iodate and an alcohol or derivative thereof. The composition demonstrates advantageous properties for synthetic acids at temperatures above 90° C. The composition is useful in various oil and gas industry operations. Preferred embodiments of the composition provide substantial advantages in matrix acidizing by increasing the effectiveness of wormholing.

A non-hazardous cleaning solution/process has been developed to remove oxide residues from the surface of blackened needles. Low concentrations of citric acid solution are mixed with blackened needles and treated in an ultrasonic tank for short period of time (<5 minutes). The oxide residues are substantially removed. Quite surprisingly and unexpectedly, the penetration performance of the cleaned needles are greatly improved by up to 50% over other tested cleaning solutions.

A cleaning solution for a turbine engine includes water; a first organic acidic component that comprises citric acid; a second organic acidic component that comprises glycolic acid; isopropylamine sulphonate; alcohol ethoxylate; triethanol amine; and sodium lauriminodipropionate. The cleaning solution has a pH value between about 2.5 and about 7.0.

Provided is an acid-pickling additive for a surface oxide scale of a stainless steel material, a preparation method thereof and an acid-pickling method. The acid-pickling additive consists of 1 to 10 parts by weight of an alcohol amine compound, 0.1 to 5 parts by weight of a metal complex ligand, 0 to 10 parts by weight of a nitrogen-containing organic cyclic compound, 0 to 3 parts by weight of an alcohol compound, 0 to 3 parts by weight of a plant extract, and 1 to 2 parts by weight of water. This acid-pickling additive can solve the problems of high energy consumption, environmental pollution, and high cost in the existing method for removing an oxide scale of a stainless steel.