Reliability of a Pulp Production Line, 1998 Engineering Conference Proceedings

Numerous process changes in pulping and bleaching were introduced during the past decade, driven by environmental pressures and increased chips cost. With this, a lot of capital was spent to install new units or rebuild the existing ones. Now, the main task is to make this capital pay back through the environmental compliance, increased production, and profits. The reliability of the production facility, in other words, maximum availability for uninterrupted production, is a key issue facing mill engineering management today.

Corrosion failure of equipment affects safety, capital cost and reliability. Since the reliability of a flow-through pulp production process is no better than that of any of its sequential unit operations (pulping, screening, washing, bleaching and drying), the failure of inexpensive parts in a unit operation, may cause a loss in production well above nominal replacement or repair costs.

The important steps towards higher reliability would be as follows: (i) identify critical events, critical parts and the means to prevent their failure, such as tighter purchase specifications; (ii) identify and update critical welding and installation procedures; (iii)qualify local contractors to adopt correct welding practices for modem materials.

More attention paid to specifying stainless casting metallurgy, fabrication procedures, design for corrosion, qualification of local welders, and correct installation procedure, supervised by a supplier or a qualified inspector, may save a lot more money in terms of prevented loss of production, than an incremental cost of additional specifications or enforcement.