Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Research on Combustion of Black-Liquor Drops



A Macek


Black liquor, the major by-product of the kraft process for production of pulp, is one of the most important industrial fuels. It is burned in recovery boilers in the form of large spray drops (mm), with the objective of simultaneous recovery of heat and chemicals (sodium and sulfur). Even though black-liquor combustion in boilers has been practiced for over half a century, research efforts toward improvement of combustion efficiency and abatement of environmental emissions are of much more recent. The present paper addresses a specific aspect of that research, namely, elucidation of processes which occur during combustion of black-liquor drops in boiler-gas streams. The paper (a) gives a brief description of the kraft process, (b) reviews the experimental and theoretical (modeling) research advances on combustion of kraft-liquor drops during the 1980s and 1990s, [c] reexamines the results of an earlier combustion study in which black-liquor drops were observed in free flight at temperatures near those in recovery boilers, and (d) recommends input for the modeling of in-flight combustion of kraft-liquor drops in recovery boilers.
Progress in Energy and Combustion Science
No. 3


black liquor, combustion, draft process, pulp & paper processing, recovery boiler


Macek, A. (1999), Research on Combustion of Black-Liquor Drops, Progress in Energy and Combustion Science (Accessed April 24, 2024)
Created June 1, 1999, Updated February 17, 2017