Official and community-shared resources often provide parts of the manual:
is a highly sought-after companion for students of the classic 1981 textbook and its subsequent editions. While the original text was published in 1981, Spanish editions and related student resources gained significant traction in academic circles around 2000–2003. Key Content of the Solution Manual
solucionario de "Operaciones de separación por etapas de equilibrio en ingeniería química" de Henley y Seader