Method for controlling NOx concentration in exhaust gas in combustion facility using pulverized coal

Patent metadata

Field	Value
Publication number	US-9551485-B2
Application number	US-201213980993-A
Country	US
Kind code	B2
Filing date	Jan 16, 2012
Priority date	Feb 25, 2011
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

A method for controlling an NOx concentration in an exhaust gas in a combustion facility by: measuring a reaction velocity k i of each of a plurality of chars, each corresponding to a plurality of types of pulverized coals; determining a relationship between the NOx concentration in the exhaust gas and the reaction velocity k i for each of the chars; (iii) blending the plurality of the types of the pulverized coal, wherein a blending ratio of the plurality of the types of the pulverized coal is determined by using, as an index, a reaction velocity k blend of the char of the blended pulverized coal, which corresponds to a target NOx concentration or below, on the basis of the relationship; and supplying the blended pulverized coal to the combustion facility as the fuel of the combustion facility.

First claim

The invention claimed is:

1. A method for controlling an NOx concentration in an exhaust gas in a combustion facility that uses a pulverized coal as a fuel, comprising in the following order:
measuring a reaction velocity of each of a plurality of chars represented by k i and corresponding to a plurality of types of pulverized coals;
determining a relationship between the NOx concentration in the exhaust gas and a reaction frequency factor, which is represented by A i , of the reaction velocity k i for the each of the chars in the plurality of chars;
blending the plurality of the types of the pulverized coal, to obtain a blended pulverized coal, wherein a blending ratio of the plurality of the types of the pulverized coal is determined by using, as an index, a reaction frequency factor of the char of the blended pulverized coal, which is represented by A blend and which corresponds to a target NOx concentration or below, on the basis of the relationship;
supplying the blended pulverized coal to the combustion facility as the fuel of the combustion facility;
wherein the reaction frequency factor for the each of the plurality of the chars, A i , is determined by:
drawing a curve of a time change of weight loss for the each of the plurality of the types of the pulverized coals under the condition of a plurality of temperatures by using a thermal balance;
dividing inclination of a tangent of the curve by a measured partial pressure of oxygen, thereby determining the reaction velocity of the each of the plurality of the chars, k i at the respective temperatures;
subsequently drawing an Arrhenius plot which sets (1/measurement temperature) for the horizontal axis and sets a value of the reaction velocity of the char, k i , in the measurement temperature for the vertical axis; and
determining the reaction frequency factor for the each of the plurality of the chars, A i , from an intercept of the vertical axis of the Arrhenius plot.

Assignees

• Takayama Yoshinori
• Shima Hirokazu
• Mitsubishi Materials Corp

Inventors

• Takayama Yoshinori
• Shima Hirokazu

Classifications

• F23N2221/10

  Analysing fuel properties, e.g. density, calorific · CPC title

• C04B7/364 Primary

  Avoiding environmental pollution during cement-manufacturing · CPC title

• F23N5/003

  using detectors sensitive to combustion gas properties (F23N5/02, F23N5/18 - F23N5/26 take precedence) · CPC title

• C04B2/108 Primary

  Treatment or selection of the fuel therefor · CPC title

• F23N1/002

  using electronic means (F23N1/04 - F23N1/10 take precedence) · CPC title