Disclosed are compositions and methods for preventing or reducing polymer formation and polymer deposition in equipment used in petrochemical processes. An antifoulant composition includes a combination of one or more antioxidants; one or more antipolymerants; one or more dispersants; and one or more solvents. A method of preventing or reducing fouling of process equipment used in an industrial process is also described. The method includes introducing into the process equipment an antifoulant composition, the antifoulant composition comprising a combination of one or more antioxidants; one or more antipolymerants; one or more dispersants; and one or more solvents.

Disclosed are compositions and methods for preventing or reducing polymer formation and polymer deposition in equipment used in petrochemical processes. An antifoulant composition includes a combination of one or more antioxidants; one or more antipolymerants; one or more dispersants; and one or more solvents. A method of preventing or reducing fouling of process equipment used in an industrial process is also described. The method includes introducing into the process equipment an antifoulant composition, the antifoulant composition comprising a combination of one or more antioxidants; one or more antipolymerants; one or more dispersants; and one or more solvents.

Disclosed is a valve mechanical linkage system. A valve comprises a main valve and a secondary valve; the system comprises a first transmission mechanism and a second transmission mechanism; the first transmission mechanism is connected with the main valve and used for converting the up-and-down reciprocating motion of the main valve into a rotational reciprocating motion; the first transmission mechanism and the second transmission mechanism are connected by means of a coupling (4), and the rotational force of the rotational reciprocating motion is transferred to the second transmission mechanism by means of the coupling (4); the second transmission mechanism is connected with the secondary valve, and achieves on-off control on the secondary valve by converting the rotational reciprocating motion into the up-and-down reciprocating motion.

The invention relates weldments useful as heat transfer tubes in pyrolysis furnaces. The invention relates to tubes that are useful in pyrolysis furnaces. The weldments include a tubular member and at least one mixing element. The tubular member comprises an aluminum-containing alloy. The mixing element comprises an aluminum-containing alloy. The mixing element's aluminum-containing alloy can be the same as or different from the tubular member's aluminum-containing alloy. Other aspects of the invention relate to pyrolysis furnaces which include such weldments, and the use of such pyrolysis furnaces for hydrocarbon conversion processes such as steam cracking.

The invention relates weldments useful as heat transfer tubes in pyrolysis furnaces. The invention relates to tubes that are useful in pyrolysis furnaces. The weldments include a tubular member and at least one mixing element. The tubular member comprises an aluminum-containing alloy. The mixing element comprises an aluminum-containing alloy. The mixing element's aluminum-containing alloy can be the same as or different from the tubular member's aluminum-containing alloy. Other aspects of the invention relate to pyrolysis furnaces which include such weldments, and the use of such pyrolysis furnaces for hydrocarbon conversion processes such as steam cracking.

Fouling and/or asphaltene agglomeration (or flocculation) in midstream processes and transportation and in upstream transportation of a hydrocarbon oil is reduced by providing in the oil an additive combination including; (A) a polyalkenyl-substituted carboxylic acid or anhydride, and (B) a metal detergent system comprising a hydrocarbyl-substituted hydroxybenzoate metal salt or a hydrocarbyl-substituted sulfonate metal salt or a mixure of both salts or a complex thereof,
where the mass:mass ratio of (A) to (B) is in the range of 20:1 to 1:20 and the treat rate of the additive is in the range of 5 to 10000 ppm by mass.

A method for cleaning a metal surface of a metal component of an industrial plant is disclosed comprising measuring the electrical resistance R.sub.A1 of a metal component over a cleaned area of the metal surface with a resistance meter, comparing the electrical resistance R.sub.A1 measured with a pre-determined electrical resistance value R.sub.DET, assessing whether R.sub.A1 is greater, smaller or equal to R.sub.DET, and repeating cleaning if the electrical resistance R.sub.A1 measured is greater than R.sub.DET, or terminating cleaning of the surface area of the metal component if R.sub.A1 is smaller than or identical to R.sub.DET.

The present invention concerns a method of weakening and removal of coke or carbonaceous material which deposits as a result of thermal cracking of hydrocarbons on the inner walls of coils, piping, tubing, and in general, hydrocarbon processing equipment.

The present invention concerns a method of weakening and removal of coke or carbonaceous material which deposits as a result of thermal cracking of hydrocarbons on the inner walls of coils, piping, tubing, and in general, hydrocarbon processing equipment.

A reactor has an inner surface accessible to the hydrocarbon and comprising a sintered product of at least one of cerium oxide, zinc oxide, tin oxide, zirconium oxide, boehmite and silicon dioxide, and a perovskite material of formula: A.sub.aB.sub.bC.sub.cD.sub.dO.sub.3-. 0<a<1.2, Gb1.2, 0.9<a+b1.2, O<c<1.2, 0d1.2, 0.9<c+d1.2, 0.5<<0.5. A is selected from calcium, strontium, barium, and any combination thereof. B is selected from lithium, sodium, potassium, rubidium, and any combination thereof. C is selected from cerium, zirconium, antimony, praseodymium, titanium, chromium, manganese, ferrum, cobalt, nickel, gallium, tin, terbium and any combination thereof. D is selected from lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetiura, scandium, titanium, vanadium, chromium, manganese, ferrum, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, gallium, indium, tin, antimony and any combination thereof.