Safety Issues in Design and Operation of Solvent Pulping Mills, 1992 Solvent Pulping Symposium Proceedings

The Alcell pulping process, an ethyl-alcohol based pulping process, produces pulp from hardwood and separates the wood into its basic components: cellulose, lignin, and hemi-cellulose sugars, recovering them without destroying them as in the sulphur and caustic processes and importantly without environmental impact. The process operates at high pressure (400 psig) and temperature (195°C) using 60% alcohol as an extraction medium in a reactor vessel. These conditions are above the flash point of the alcohol and introduce the potential hazards of fire, explosion, and accidental release of process materials which may be toxic. Furthermore, due to the climate conditions at the site (Northeastern Canada), the process is operated indoors, greatly increasing the hazard potential to personnel and the equipment should an accident occur of disaster proportions.

The paper addresses the approach utilized by Du Pont Safety and Environmental Management Services to perform a Process Safety Management Evaluation during the final stages of construction and start-up planning of the plant, which was designed by Alcell and its process design contractors. It provides an overview of the safety and risk assessment techniques that can be used to determine whether the existing engineering, operational, maintenance, and management controls are sufficient to identify and manage the potential hazards of the process. Recommendations on administrative systems such as safety rules, work permit systems, and emergency planning are also discussed.