Patent ID: 6318305
Filing Date: 2001-11-20
Classification: F22B,F24H

Abstract:
A water-tube boiler comprising:a first water tube array made up of a plurality of first water tubes arranged into an annular shape;a combustion chamber defined inside the first water tube array;a first opening defined at part of the first water tube array;a cooling water tube array made up of a plurality of cooling water tubes arranged into an annular shape in a zone within the combustion chamber where burning-reaction ongoing gas is present;gaps provided between adjacent cooling water tubes so as to permit the burning-reaction ongoing gas to flow through; anda burning-reaction continuing zone, where burning reaction is continuously effected, provided in a space between the cooling water tube array and the first water tube array, whereby the burning-reaction ongoing gas generally uniformly contacts the individual cooling water tubes wherein said cooling water tubes, are constructed and arranged so that a temperature of the burning-reaction after contacting said cooling water tubes is lowered to 1400.degree. C. or lower, whereby generation of NOx is reduced.