Kurita Water Industries Ltd.

Shiro Taya

Yukimasa Shimura

Takatoshi Sato

Takayasu Ueda

Akitomo Terada

Masakazu Koizumi

Moriyasu Itoh

A boiler water treatment chemical includes a heterocyclic compound with N-substituted amino group, or the salt thereof, and alkaline agent and/or water soluble polymer.

Oxygen scavenger and boiler water treatment chemical

An oxygen scavenger, containing a heterocyclic compound having a N-substituted amino group as an effective component, can adequately exhibit the oxygen scavenging effect in not only feed water lines for high temperature water, a boiler, and steam and condensate return lines, but also feed water lines for low temperature water. The oxygen scavenger contains: a heterocyclic compound having a N-substituted amino group or a salt thereof; a hydroxybenzene derivative and/or a naphthoquinone derivative; and neutral amine.

Oxygen scavenger

Water treating agent and water treating method

An oxygen scavenger characterized in that the effective component thereof consists of a heterocyclic compound with N--N bond in a ring thereof An oxygen scavenger characterized in that the effective component thereof consists of a heterocyclic compound with N-substituted amino group. An oxygen scavenger characterized in that the effective component thereof consists of a heterocyclic compound represented by the following formula: ##STR1## (wherein a, b are integers between 0 and 5 to satisfy a relation '2.ltoreq.a+b.ltoreq.5'). ##STR2## An oxygen scavenger characterized in that the effective component thereof consists of azodicarbonamide. An oxygen scavenger characterized by including a heterocyclic compound with N-substituted amino group, or the salt thereof, and a hydroxybenzene derivative. Those may contain further neutral amine, alkalic agent and/or water soluble polymer.

Method of using oxygen scavenger and removing oxygen from water

There disclosed a boiler compound which comprises as the effective components thereof: (A) metabisulfurous acid or metabisulfites; (B) aliphatic dicarboxylic acids or salts thereof represented by the general formula:

Boiler water treatment composition

Method of removing dissolved oxygen in a boiler water system

An anticorrosive for vapor/condensed water systems, which comprises at least one aminodiol represented by the following general formula: ##STR1## (in which R.sub.1, R.sub.2 and R.sub.3 each represents --H, --CH.sub.3, --C.sub.2 H.sub.5 or C.sub.3 H.sub.7 ; and n represents an integer of 0 to 2) and the process for inhibiting the corrosion of vapor/condensed water systems, which comprises at least one aminodiol as mentioned above to a boiler feed water at the concentration of 0.1 to 500 mg/l. The aminodiol, when added to feed water, migrates into condensed water in large quantities and inhibits the corrosion of piping systems and boilers in highly effective manner.

Process for inhibiting corrosion of vapor/condensed water system

Disclosed is a boiler chemical having both oxygen scavenging function and softening function. The boiler chemical contains a starch phosphate and/or a water-soluble salt thereof. A starch phosphate and/or a water-soluble salt thereof are/is added to the boiler feed water in a given amount of an amount as determined by the phosphate ion concentration in the boiler water and scaled, as measured, whereby the boiler is prevented from being corroded.

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Tokyo, Japan

Shiro Taya