Abstract: A waste heat recovery method can provide heat recovery from exhaust gases, full firing of exhaust gases, and auxiliary burning, either simultaneously or independently. Such method is carried out by installing a tube-nested (or heat-absorbing water tube furnace-inserted type) combustion chamber in a boiler of a cogeneration system or combined cycle system or the like which generates both heat and power. The boiler is provided with a combined full firing burner and auxiliary burner confronted by the exhaust gas entrance. This structure allows for elimination of a separate auxiliary chamber and thus has made it possible to provide a waste heat boiler of a simplified structure which is smaller in size and thus occupies less space, at a reduced price and with a greatly expanded heat-to-electricity ratio. Accordingly, the boiler of the invention has a greatly extended range of applications.

Abstract: With a view toward solving various problems of prior-art gas turbine plants by applying a tube-nested combustion chamber type combustor in place of the combustor of the prior-art gas turbine, a combustor of a gas turbine used in a gas turbine power plant is equipped with a heat-absorber-water-tube-inserted combustion chamber in which fuel is burnt with combustion air only. Consequently, the NO.sub.x generated from the gas turbine power plant is notably reduced, no CO and unburnt hydrocarbons (UHC) are produced and, moreover, the amount of power generated and the utilizable calories of the steam are increased for the benefit of an enhanced overall heat efficiency. This enables the combustion space of the gas turbine power plant to be greatly diminished, with a resultant widened utilization range of gas turbines.

Abstract: In flue and water tube boilers provided with water tubes arranged in a combustion reaction zone or a convective heating zone, the values of L/D or H/D satisfy the following relationships:1.8.ltoreq.L/D.ltoreq.2.5 and1.2.ltoreq.H/D.ltoreq.1.7and the water tubes are disposed in an (aligned) in-line arrangement. L(mm) is the longitudinal pitch of the water tubes taken in the direction of gas flow, D(mm) is the outer diameter of the water tubes and H(mm) is the transverse pitch of the water tubes taken at right angles to the direction of gas flow.