Excess Air Control For Cracker Furnace Burners

• US 20110062056A1
• Filed: 11/02/2007
• Published: 03/17/2011
• Est. Priority Date: 05/16/2005
• Status: Abandoned Application

• Current Assignee: Dow Global Technologies, Inc. (Dow, Inc.)
• Original Assignee: Dow Global Technologies, Inc. (Dow, Inc.)
• Inventors: Reed, Chris, Frederick, Gerald D., Tate, James D., Lipp, Charles, Irving, Sylvester, Weber, Andy
• Application Number:
  US12/735,360
• Publication Number:
  US 20110062056A1
• Time in Patent Office: Days
• US Class Current: 208/106
• CPC Class Codes: C10G 9/206 controlling or regulating the tube furnaces
• CPC Class Codes: F27D 19/00 Arrangements of controlling devices
• CPC Class Codes: F27D 21/00 Arrangements of monitoring devices; Arrangements of safety devices
• CPC Class Codes: F27D 99/0033 using burners manufacture of steel in an electric arc furnace equipped with burners C21C5/5217
• CPC Class Codes: G01N 21/39 using tunable lasers

Abstract

A method for control of the air/fuel ratio of the burner(s) (excess air) of a thermal cracker which includes three steps. The first step is to direct a wavelength modulated beam of near infrared light from a tunable diode laser through combustion gas from the burner to a near infrared light detector to generate a detector signal. The second step is to analyze the detector signal for spectroscopic absorption at wavelengths characteristic for an analyte selected from the group consisting of oxygen, carbon monoxide and nitrogen oxide to determine the concentration of the analyte in the combustion gas. The third step is to adjust the air/fuel ratio of the burner(s) (excess air) in response to the concentration of the analyte of the second step.

Claims

1. A method for control of the air/fuel ratio of the burner(s) of a thermal cracker for producing olefins which comprises a birebox portion, an bridge wall portion and a convection portion, comprising the steps of:

(a) directing a wavelength modulated beam of near infrared light from a tunable diode laser through combustion gas from the burner to a near infrared light detector to generate a detector signal wherein the beam is shown directed through the bridge wall portion;

(b) analyzing the detector signal for spectroscopic absorption at wavelengths characteristic for an analyte selected from the group consisting of oxygen, carbon monoxide and nitrogen oxide to determine the concentration of the analyte in the combustion gas; and

(c) adjusting the air/fuel ratio of the burners (excess air) in response to the concentration of the analyte of step (b).

2. The method of claim 1, wherein the wavelength of the near infrared light from the tunable diode laser is in the range of from about 500 to about 15000 wavenumbers.

3. The method of claim 1 wherein the concentrations of both oxygen and carbon monoxide are determined.

4. The method of claim 1 wherein the wavelength used to determine concentration of carbon monoxide is about 2333 nanometers.