Method for improving efficiency of steam heating, and papermaking method

A method for improving heating efficiency of steam, comprising:

• preparing an aqueous emulsion containing a condensed water film formation-suppressing amine and an emulsifier having hydrophilic-lipophilic balance of 12-16, and
• adding the aqueous emulsion containing the condensed water film formation-suppressing amine in a heating step of heating a material to be heated by a steam drier via a metallic material,
• wherein the aqueous emulsion condensing the condensed water film formation-suppressing amine is added in a steam at a steam pipe or a steam header for supplying the steam to the steam dryer that is disposed right before the steam dryer,
• the condensed water film formation-suppressing amine is added so that a concentration of the condensed water film formation-suppressing amine in the steam is 0.01 to 10 ppm, and
• two or more neutralizing amines having a pH-adjusting function are concurrently used together with the condensed water film formation-suppressing amine to reduce corrosion rate of the steam drier and steam pipe, the neutralizing amines being added in an amount of 0.1 to 50 ppm based on an amount of steam,
• wherein the condensed water film formation-suppressing amine is a polyamine represented by the following general formula (1):
• R1—[NH—(CH2)m]n—NH2 (1)
• wherein R1 represents a saturated or unsaturated hydrocarbon group having 10 to 22 carbon atoms;
• m is an integer of 1 to 8, and n is an integer of 1 to 7;
• and when n is 2 or more, a plurality of NH—(CH2)m may be identical or different.