Boiler and combustion control method

Abstract

Provided is a boiler (100) including: a burner (5); a fuel supply unit (10) for supplying fuel to the burner (5); a blowing unit (20) for supplying air to the burner (5); and a control unit (30) for adjusting an amount of fuel to be supplied to the burner (5) and a quantity of air to be supplied to the burner (5), in which the control unit (30) has a reference amount computing portion for calculating a reference fuel amount and a reference air quantity to be supplied to the burner (5) with respect to a required load, an air quantity computing portion that corrects the reference air quantity based on a temperature of the air to be supplied to the burner (5) and a temperature of the fuel to be supplied to the burner (5) and calculates the corrected air quantity as a supply air quantity, and a control portion that controls combustion at the burner based on the reference fuel amount and the supply air quantity.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a boiler and a combustion control method making it possible to perform combustion at a predetermined air ratio and to suppress generation of NOx in the exhaust gas.[0003]2. Description of the Related Art[0004]It is important for a boiler to be capable of performing stable combustion with high thermal efficiency. In view of this, there have been proposed air ratio control boilers or combustion apparatuses in which control is performed such that combustion is performed at a predetermined air ratio.[0005]For example, JP 2001-272030 A proposes an air-fuel ratio control (air ratio control) monitoring method for a burner in a boiler and an air-fuel ratio control monitoring apparatus for executing the method. In the method and the apparatus, in response to a load command from a control panel, the pressure of the combustion air to be supplied to the burner and the pressure of the fuel to be supp...

AI Technical Summary

Benefits of technology

[0009]In view of above-mentioned requirement and the problems in the prior art, it is an object of the present invention to provide a boiler and a combustion control method which are of a relatively simple construction, in which combustion is performed at a predetermined air ratio, and which can suppress generation of NOx in the exhaust gas.

[0014]The boiler according to the present invention has a relatively simple construction, and is capable of performing combustion at a predetermined air ratio, suppressing generation of NOx in the exhaust gas in a stable manner, and performing stable combustion with high thermal efficiency. Further, according to the combustion control method of the present invention, it is possible to suppress generation of NOx to a level of 12 ppm or less in normal combustion.

Problems solved by technology

However, none of the above-mentioned conventional techniques proposes a boiler or a combustion control method capable of controlling both the air ratio and the NOx generation in the exhaust gas and suppressing generation of NOx in a stable manner even if there is a change in outside temperature due to seasonal variations or the like.

However, it is intended for the control of the air ratio when the air ratio is outside a predetermined range, but it is not capable of accurately controlling the air ratio.

The air ratio automatic correction system for a combustion apparatus proposed in JP 10-47654 A has a problem in that it requires a complicated construction and control.

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