A method for selecting chemical agents for removing scale, the chemical agents being adapted for scale and its base material. A method for selecting chemical agents for removing scale, the method including steps of: obtaining coordinates A of an intrinsic physical property value based on a Hansen solubility parameter of an entire scale of interest; obtaining coordinates B of an intrinsic physical property value based on a Hansen solubility parameter of a surface on a base material side of the scale of interest; obtaining coordinates C of an intrinsic physical property value based on a Hansen solubility parameter of a base material of interest; selecting a penetrant having coordinates D of an intrinsic physical property value based on a Hansen solubility parameter based on an interaction radius Ra of the scale of interest with the coordinates A at the center; selecting a remover having coordinates E of an intrinsic physical property value based on a Hansen solubility parameter based on a positional relationship between the coordinates B and the coordinates C; and selecting an inducer having coordinates F of an intrinsic physical property value based on a Hansen solubility parameter based on a positional relationship between the coordinates D and the coordinates E.

In a geothermal plant, alternately injecting an acid composition and a caustic composition removes or inhibits scale build-up.

Provided herein is a composition for treating aluminum containing surfaces, wherein the composition includes a reaction product of at least one amine-functionalized organosilane and/or oligomer and/or polymer thereof and at least one fatty acid, wherein the molar ratio of the amino group/s of the at least one amine-functionalized organosilane and/or oligomer and/or polymer thereof and of the at least one fatty acid is 1.2:1 to 1:2, and wherein the at least one amine-functionalized organosilane and/or oligomer and/or polymer thereof is linked to the at least one fatty acid by at least one carboxylic acid/amine salt bond and/or at least one amide bond.

Provided herein is a composition for treating aluminum containing surfaces, wherein the composition includes a reaction product of at least one amine-functionalized organosilane and/or oligomer and/or polymer thereof and at least one fatty acid, wherein the molar ratio of the amino group/s of the at least one amine-functionalized organosilane and/or oligomer and/or polymer thereof and of the at least one fatty acid is 1.2:1 to 1:2, and wherein the at least one amine-functionalized organosilane and/or oligomer and/or polymer thereof is linked to the at least one fatty acid by at least one carboxylic acid/amine salt bond and/or at least one amide bond.

Disclosed herein are compositions and methods of mitigating scale in phosphoric acid and ammonium phosphate plants. Scale-mitigating compositions of the invention can be added to phosphoric acid before or during the concentration in the evaporator cycle of a phosphoric acid plant. The compositions retard the formation of scale on surfaces in contact with the phosphoric acid, and thus time between cleaning is extended and plant productivity increased. Further, the scale that forms is softer and more easily cleaned from surfaces, reducing non-operation time of the plant and/or evaporator. Methods of mitigating scale formation in phosphoric acid production and phosphoric acid handling plants are disclosed. In the methods, scales accumulate more slowly and are softer, more tractable, and more easily cleaned from surfaces to which they adhere.

The present disclosure provides a formulation and methods for simultaneously dissolving metal sulfide scales, inhibiting acid gas corrosion, and inhibiting the formation of calcite and barite in a system having low or high shear stress conditions due to fluid movement, in which the formulation contains a THP+ salt, one or more corrosion inhibitors, one or more scale inhibitors, and one or more acid corrosion inhibitors. The formulation may be applied to the system in diluted or undiluted form, and continuously or in batch style.

An additive comprising one or more C.sub.3-C.sub.12 hydroxycarboxylic acids and/or one or more C.sub.3-C.sub.12 hydroxycarboxylic acid salts may be added to an aqueous system having galvanized metallurgy or a carbon steel surface in an effective amount to passivate a galvanized coating on the metallurgy or to decrease white rust formation or other types of corrosion upon the galvanized metallurgy or carbon steel surface in an aqueous system. In a non-limiting embodiment, the C.sub.3-C.sub.12 hydroxycarboxylic acid or the C.sub.3-C.sub.12 hydroxycarboxylic acid salt additive may utilize the zinc in the galvanized coating to achieve passivation. The passivation may occur while the system is shut down or in service. The aqueous system may be or include a cooling tower, a cooling water system, and combinations thereof. The additive may be used with or in the absence of a phosphorous-containing compound.

A method and system for operating a seal gas compressor utilized in a direct reduction process including: monitoring a pH level of a water stream used in the seal gas compressor, wherein the pH level of the water stream is affected by a reformer flue gas stream that comes into contact with the water stream, wherein the monitoring step is carried out one or more of upstream of the seal gas compressor and downstream of the compressor; and adjusting the pH level of the water stream to maintain the pH level of the water stream within a predetermined range based on feedback from the monitoring step. The method includes maintaining the pH level of the water stream upstream of the seal gas compressor in a range between 7.5 and 10 and maintaining the pH level of the water stream downstream of the seal gas compressor in a range between 7.8 and 9.5.

A method and system for operating a seal gas compressor utilized in a direct reduction process including: monitoring a pH level of a water stream used in the seal gas compressor, wherein the pH level of the water stream is affected by a reformer flue gas stream that comes into contact with the water stream, wherein the monitoring step is carried out one or more of upstream of the seal gas compressor and downstream of the compressor; and adjusting the pH level of the water stream to maintain the pH level of the water stream within a predetermined range based on feedback from the monitoring step. The method includes maintaining the pH level of the water stream upstream of the seal gas compressor in a range between 7.5 and 10 and maintaining the pH level of the water stream downstream of the seal gas compressor in a range between 7.8 and 9.5.

Methods for reducing aluminosilicate containing scale in a Bayer process involving treating a Bayer process equipment surface with a scale inhibiting composition having high ionic strength prior to exposure to a Bayer process stream.