Method and apparatus for use in monitoring and controlling a black liquor recovery furnace

A method for use in monitoring a kraft chemical recovery furnace of the type in which black liquor fuel is injected into a combustion chamber and burned therein to form a bed of chemicals to be recovered, the method comprising:

• determining the profile of the bed viewed from at least one direction and producing a first output signal representing the bed profile;
• determining the temperature of the bed over at least a major portion of the bed profile and producing a second output signal representing the temperature of the bed;
• detecting particles in an upper region of the furnace and producing a third output signal representing the detected particles;
• displaying from the first, second and third output signals a visual representation of the determined profile of the bed, the determined temperature of the bed and the detected particles;
• wherein air is supplied to the furnace at plural levels within the furnace and at plural locations about the furnace at each level, and in which fuel is supplied to the furnace through at least one fuel gun or nozzle aimed into the furnace at an angle relative to horizontal, at a fuel temperature and at a fuel pressure, the method including the step of correlating the determined bed profile, determined temperature, and detected particles with furnace operating parameters selected from the group comprising the fuel nozzle angle, the fuel temperature, the fuel pressure, and the supply of air to the furnace at the plural levels and locations;
• and
• the method including the step of adjusting the furnace operating parameters in response to the determined bed profile, determined temperature and detected particles and further including the step of cleaning out the air delivery locations in response to variations in the determined bed profile, determined temperature, and detected particles.

A method for use in monitoring a kraft chemical recovery furnace of the type in which black liquor fuel is injected into a combustion chamber and burned therein to form a bed of chemicals to be recovered, the method comprising:

• determining the profile of the bed viewed from at least one direction and producing a first output signal representing the bed profile;
• determining the temperature of the bed over at least a major portion of the bed profile and producing a second output signal representing the temperature of the bed;
• detecting particles in an upper region of the furnace and producing a third output signal representing the detected particles;
• displaying from the first, second and third output signals a visual representation of the determined profile of the bed, the determined temperature of the bed and the detected particles;
• determining the profile of the bed step comprising the step of producing a digital image of the bed and background and processing the image to determine transitions in the image which correspond to transitions between the bed and background and thereby to the boundary of the bed;
• and
• wherein the digital image is comprised of successive vertical slices or columns of pixels, the step of processing the image to determine transitions comprises the step of repeatedly evaluating pixels within each vertical slice of the bed profile to determine the transition between the bed and image associated with the vertical slice, the pixels evaluated in determining the transition for a given evaluation being within a predetermined number of pixels of the pixel determined as the transition during the preceding evaluation.

A method for use in monitoring a kraft chemical recovery furnace of the type in which black liquor fuel is injected into a combustion chamber and burned therein to form a bed of chemicals to be recovered, the method comprising:

• determining the profile of the bed viewed from at least one direction and producing a first output signal representing the bed profile;
• determining the temperature of the bed over at least a major portion of the bed profile and producing a second output signal representing the temperature of the bed;
• detecting particles in an upper region of the furnace and producing a third output signal representing the detected particles;
• displaying from the first, second and third output signals a visual representation of the determined profile of the bed, the determined temperature of the bed and the detected particles;
• determining the profile of the bed step comprising the step of producing a digital image of the bed and background and processing the image to determine transitions in the image which correspond to transitions between the bed and background and thereby to the boundary of the bed;
• and
• wherein the digital image is comprised of pixels, the step of determining the bed profile including the step of identifying at least one selected element in the background, assigning a value for pixels associated with the selected element to minimize such associated pixels being determined as a transition.

A method for use in monitoring a kraft chemical recovery furnace of the type in which black liquor fuel is injected into a combustion chamber and burned therein to form a bed of chemicals to be recovered, the method comprising:

• determining the profile of the bed viewed from at least one direction and producing a first output signal representing the bed profile;
• determining the temperature of the bed over at least a major portion of the bed profile and producing a second output signal representing the temperature of the bed;
• detecting particles in an upper region of the furnace and producing a third output signal representing the detected particles;
• displaying from the first, second and third output signals a visual representation of the determined profile of the bed, the determined temperature of the bed and the detected particles;
• determining the profile of the bed step comprising the step of producing a digital image of the bed and background and processing the image to determine transitions in the image which correspond to transitions between the bed and background and thereby to the boundary of the bed;
• and
• wherein the digital image is comprised of pixels, the step of processing the image to determine transitions comprises the step of determining transitions from the method of simulated thermal annealing by applying the thermodynamic relationship (e.sup.-u/t) wherein u is a positive function of the group comprising the height of the pixel, the strength of the pixel, the memory of the pixel and continuity of the pixel and T is a simulated temperature.

A method for use in monitoring a kraft chemical recovery furnace of the type in which black liquor fuel is injected into a combustion chamber and burned therein to form a bed of chemicals to be recovered, the method comprising:

• determining the profile of the bed viewed from at least one direction and producing a first output signal representing the bed profile;
• determining the magnitude of the average temperature of the bed over at least a major portion of the bed profile and producing a second output signal representing the magnitude of the average temperature of the bed;
• detecting particles in an upper region of the furnace and producing a third output signal representing the detected particles;
• and
• displaying from the first, second and third output signals a visual representation of the determined profile of the bed, the determined magnitude of the average temperature of the bed and the detected particles.