Miura Co., Ltd.

Hiroyuki Mitsumoto

Junichi Nakajima

Junichi Kato

Takashi Ninomiya

Yoshiro Kaminokado

Boiler water is heated in a steam boiler while feed water, which has a hardness of 5 mg CaCO/L or less and is used as the boiler water, is supplied to the steam boiler. A part of the boiler water is appropriately disposed of. A chemical aqueous solution containing an alkaline metal silicate, an alkaline metal hydroxide and at least one kind of scale preventive agents of ethylenediamine tetraacetate, and its alkaline metal salt, is supplied to the feed water so that a concentration of the scale preventive agent is at least 1.5 mol equivalent times relative to the hardness of the feed water. In the steam boiler, a condensation rate of the boiler water is set so that the concentration of the scale preventive agent in the boiler water is 40 mg EDTA/L or less.

Method of operating steam boiler

To simply and accurately determine the concentration of a water treating agent in thermal equipment upon management of a supply amount of the water treating agent, a method of controlling a supply amount of a water treating agent according to the present invention includes the steps of: supplying a water treating agent containing a scale inhibitor selected from chelating agents to a water-supply system of thermal equipment; collecting a water sample from the thermal equipment; quantitatively determining the scale inhibitor in the collected water sample; and determining a concentration of the water treating agent in the thermal equipment on the basis of a quantitative value of the scale inhibitor.

Method of supply amount management of water treating agent

To provide a hardness measurement reagent unaffected by an M alkalinity in hardness measurement. A hardness measurement reagent as a one-solution type reagent includes a dye chosen from Eriochrome Black T (EBT) and Calmagite, triethanolamine, a glycol compound, and a pH buffer, in which the pH buffer includes a combination of amines selected from primary amines and secondary amines and a salt of a weak base.

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Matsuyama, Japan

Hiroyuki Mitsumoto