US 12,134,859 B2
Determining the reduction rate of a recovery boiler
Heikki Lappalainen, Varkaus (FI); Juho Nurmi, Varkaus (FI); Sauli Rissanen, Kotka (FI); and Esa Vihavainen, Varkaus (FI)
Assigned to Andritz Oy, Helsinki (FI)
Appl. No. 17/612,191
Filed by ANDRITZ OY, Helsinki (FI)
PCT Filed May 15, 2020, PCT No. PCT/FI2020/050324
§ 371(c)(1), (2) Date Nov. 17, 2021,
PCT Pub. No. WO2020/234511, PCT Pub. Date Nov. 26, 2020.
Claims priority of application No. 20195410 (FI), filed on May 17, 2019.
Prior Publication US 2022/0220671 A1, Jul. 14, 2022
Int. Cl. D21C 11/10 (2006.01); F23N 1/04 (2006.01); F23N 5/08 (2006.01); G01N 21/17 (2006.01); G01N 21/25 (2006.01); G01N 21/27 (2006.01)
CPC D21C 11/10 (2013.01) [F23N 1/042 (2013.01); F23N 5/082 (2013.01); G01N 21/251 (2013.01); G01N 21/27 (2013.01); G01N 2021/1776 (2013.01); G01N 2201/1296 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method for determining a reduction rate of a recovery boiler comprising:
obtaining a chemical smelt sample from smelt that flows from the recovery boiler;
capturing a digital frame of an image of the chemical smelt sample;
reading with a processor the digital frame including an area within the image which represents the chemical smelt sample of the recovery boiler;
determining from the digital frame an area of interest within the image comprising at least part of the area in the digital frame representing the chemical smelt sample;
determining with the processor and from pixel values of the area of interest one or more spectral characteristic values;
determining with the processor a reduction rate of the recovery boiler based on the one or more spectral characteristic values and using a reduction rate function to correlate the one or more of the spectral characteristic values to corresponding predetermined weights used to determine the reduction rate, and
controlling the recovery boiler using the reduction rate.