초록 ▼

An improved method for removing scale, sludge, corrosion and other debris and deposits from the interior of a heat exchanger vessel such as a nuclear steam generator, includes generating pressure pulses in a non-corrosive, strongly basic, amine-containing chemical cleaning agent in aqueous solution

An improved method for removing scale, sludge, corrosion and other debris and deposits from the interior of a heat exchanger vessel such as a nuclear steam generator, includes generating pressure pulses in a non-corrosive, strongly basic, amine-containing chemical cleaning agent in aqueous solution after the agent has been introduced into the interior of the vessel to create shock waves in the liquid for dislodging, dissolving and fluidizing sludge and corrosion products. The chemical cleaning agent is an aqueous solution containing at least one of the group of lower alkyl amines, e.g., dimethylamine, ethylamine, 1,2-diaminoethane, or diaminopropane, lower alkanol amines, e.g., ethanolamine, 2-methyl-2-amino-1-propanol, and 5-aminopentanol, lower alkoxy alkyl amines, e.g., 3-methoxypropylamine, and cyclic diimines, e.g., 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, 4,7-dimethyl-1,10-phenanthroline, 2,2'-bipyridine, and 4,4'-bipyridine, and terpyridine, or combinations thereof. The method further includes simultaneously recirculating the chemical cleaning agent through a filter assembly during the pressure pulsing operation in order to remove fluidized sludge and corrosion products dislodged by the pressure pulsing and chemical action, thereby affording them no opportunity to resettle back onto the surfaces of the heat exchanger vessel and interfere with the chemical cleaning of the vessel. The method reduces not only the time required for a particular chemical cleaning agent to effectively clean the vessel, but further reduces the number of times such chemicals need to be introduced into the vessel, which in turn results in the production of less radioactive liquid waste products, and minimizes new corrosion through use of relatively non-corrosive cleaning agents.

대표청구항 ▼

[ What is claimed is:] [1.] A method for removing sludge and deposits from the interior of a heat exchanger vessel, which comprises:introducing an aqueous cleaning solution containing a chemical cleaning agent into said interior of said heat exchanger vessel; and,removing said aqueous solution from

[ What is claimed is:] [1.] A method for removing sludge and deposits from the interior of a heat exchanger vessel, which comprises:introducing an aqueous cleaning solution containing a chemical cleaning agent into said interior of said heat exchanger vessel; and,removing said aqueous solution from said interior of said heat exchanger vessel,in which said aqueous cleaning solution comprises a cleaning agent from at least one of the group consisting of a carrier agent and an intercalation agent, or a combination thereof, wherein said carrier agent is selected from the group consisting of dimethylamine, ethylamine, 1,2-diaminoethane, and diaminopropane, ethanolamine, 2-methyl-2-amino-1-propanol, 5-aminopentanol, and methoxypropylamine.