Process audits – running plants at maximum efficiency

Geoff Covey, Dennis Shore and Ross Patterson

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Poor profitability and shortage of funds are discouraging capital investment in the Australian pulp and paper industry; instead there is a focus on cost reduction. However, experience suggests that most plants are running at below optimum efficiency and often have artificial bottlenecks which are limiting capacity.

Careful comparison of the differences between the actual operation of a mill and the originally intended operating parameters, and of the stated reasons for these deviations will often reveal minor changes in procedures and low cost modifications that can make significant improvements to profitability.

This paper describes how such deviations arise and the procedure by which they can be identified and corrected.


In the current economic climate there is a general reluctance to make large capital investments in new production facilities or even in major upgrades. However, there is still a significant focus on reducing operating costs. All too often this is achieved by cost cutting measures and by minor upgrades of pieces of equipment.

An alternative which is all too infrequently considered, but which will often result in a much higher return on investment, is conducting process audits. The objective here is to compare the actual operation of the plant with its original design intent and on the basis of identifying the reasons for these differences to improve its performance.

Technical visitor s to a plant will usually find a large number of practices which deviate from the official way that the plant is to be operated. If these visitors were involved with the original design or ope ration of the plant, they will find even more deviations from what was originally intended.

During a hypothetical plant commissioning phase, machine A has a mysterious gremlin.

The start up engineers tweak the associated flow rates, pressures, and temperatures to get some product out of the front door at this stage it is output, not efficiency that matters . The process stabilises but the original gremlin remains lurking in the background noise. The ‘ start up cowboys ’ are replaced with real engineers, and new and enthusiastic operating staff. The overall plant performance is gradually squeezed up the start up curve. Plant reporting and the operating budget become fixed, and process centrelines are established, BUT, all of these incorporate allowance s for the original malignant and undetected gremlin. There is an old American adage that when you are up to your ears in alligators, you tend to lose sight of the original intention to drain the swamp.