BLSpray: Understanding the Effect of Black Liquor Properties and Splash Plate Nozzle Configuration on Spray Characteristics, 2004 International Chemical Recovery Conference

Black liquor spraying is an important parameter for proper combustion in a chemical recovery boiler. Understanding the spray distribution and droplet size of a particular operation allows the operator to optimise combustion. An ideal spray minimises carryover while maintaining a char bed shape that maximises chemical reduction.

Measuring spray distribution and droplet mean diameter in-situ is very difficult. As a consequence, work began in September 2000 to develop a computer code (BLSpray) that can accurately predict black liquor spray flow characteristics. The three main uses of the code will be as follows: develop an improved nozzle based on understanding the effect changes in nozzle configuration and black liquor properties have on spray characteristics; given the operating parameters of a boiler, predict the black liquor droplet size, or conversely, determine the optimum nozzle selection for the specific operation; provide input for CFD modelling. The present code has been validated against laboratory results.

This paper will describe the status of the code. It will also describe the results obtained by varying black liquor properties and nozzle configuration. Liquor properties considered include viscosity, surface tension and density. Nozzle configurations considered include velocity, sideskirts, different plate shapes and different bore shapes.