Online detection method of gaseous alkali metal concentration in boiler burning flame

Patent metadata

Field	Value
Publication number	US-9651480-B2
Application number	US-201515104427-A
Country	US
Kind code	B2
Filing date	Jun 4, 2015
Priority date	May 18, 2015
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

Provided is an online detection method of gaseous alkali metal concentration in boiler burning flame. The method includes selecting the user characteristic spectral line to be measured; based on the characteristic spectral line of the alkali metal, constructing a fitting model between radiation strength of the characteristic spectral line of the alkali metal in the burning flame and the gaseous alkali metal concentration and flame temperature; calibrating the spectrograph under absolute radiation strength; measuring a flame object corresponding to an alkali metal concentration by the calibrated spectrograph to obtain the radiation strength and flame temperature of the characteristic spectral line of the alkali metal. The detection method can detect the concentration of the gaseous alkali metal in the burning flame of the detection furnace quickly and accurately as well as detect the content of the base metals, involves simple devices, low cost, and is suitable for field measurement.

First claim

The invention claimed is:

1. An online detection method of gaseous alkali metal concentration in boiler burning flame, the method comprising steps of:
(1) constructing a fitting model based on characteristic spectral line: selecting characteristic spectral line of an alkali metal to be measured; based on the characteristic spectral line of the alkali metal, constructing a fitting model between radiation strength I Alkali of the characteristic spectral line of the alkali metal in the burning flame and the gaseous alkali metal concentration C Alkali and flame temperature T:

I
Alkali

=

∑
0
m

⁢

⁢

∑
0
n

⁢

⁢

a
mn

⁡

(

C
Alkali

)

m

⁢

T
n

,

 where α mn is a polynomial fitting coefficient; orders m, n are positive integers; T is a flame temperature of a measuring object, and the unit thereof is K;
(2) calibrating: calibrating a spectrograph under absolute radiation strength; measuring a flame object corresponding to an alkali metal concentration by the calibrated spectrograph to obtain the radiation strength and flame temperature of the characteristic spectral line of the alkali metal; introducing radiation strengths and flame temperatures corresponding to different alkali metal concentrations to the fitting model

I
Alkali

=

∑
0
m

⁢

⁢

∑
0
n

⁢

⁢

a
mn

⁡

(

C
Alkali

)

m

⁢

T
n

 to obtain a specific value of the polynomial fitting coefficient α mn ; and
(3) online detection: measuring a radiation spectrum of the boiler burning flame in real time by the calibrated spectrograph to obtain the radiation strength and the flame temperature corresponding to the characteristic spectral line of the alkali metal; introducing the radiation strength and the flame temperature corresponding to the characteristic spectral line of the alkali metal, and the specific value of the polynomial fitting coefficient α mn in step (2) to the fitting model constructed in step (1), to calculate an actual concentration of gaseous alkali metal in the boiler burning flame to realize the online detection of gaseous alkali metal concentration in the boiler burning flame.

2. The method of claim 1 , wherein the construction of the fitting model

I
Alkali

=

∑
0
m

⁢

⁢

∑
0
n

⁢

⁢

a
mn

⁡

(

C
Alkali

)

m

⁢

T
n

is as follows:
(1.1) according to flame spectrometric analysis, atom or ion of an element absorbs energy of high temperature flame and is excited from the ground state; the distribution of the ground state atom N 0 and the excited state atom N i of unit volume meets the maxwell-boltzmann distribution rule in statistic mechanics, namely:

N
i

=

g
i

g
0

·

N
0

·

ⅇ

-

E
i

kT

;

(
1
)

Assignees

• Univ Huazhong Science Tech

Inventors

• Lou Chun
• Tian Yanfei

Classifications

• G01N33/0036 Primary

  specially adapted to detect a particular component (physical analysis of gaseous biological material G01N33/497) · CPC title

• G01N21/72

  using flame burners · CPC title

• G01N21/31 Primary

  Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry {(G01N21/72 takes precedence)} · CPC title

• G01J3/30

  Measuring the intensity of spectral lines directly on the spectrum itself (G01J3/42, G01J3/44 take precedence) · CPC title