Published Papers

Below are a selection of papers written and published by members of the Covey Consulting team.

Process audits – running plants at maximum efficiency

Geoff Covey, Dennis Shore and Ross Patterson

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ABSTRACT

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.

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Multi-level integration in bioproducts manufacture

Geoff Covey

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Abstract

Biorefineries are often seen as analogous to oil refineries, but in reality they will probably have a quite different scope as they will produce a narrower range of liquid fuels but a much broader range of chemicals and solid products.

Further, whereas oil is taken from the ground and then all taken to oil refineries for processing, the logistics of moving ligno-cellulose from its point of growth to the bio refinery will be much more complicated.

To this must be added difficulties such as competition for land use and conservation issues.

This paper will discuss how these factors might be addresses and how integration might be achieved at all levels in the chain from forests to finished products.

Keywords Biorefining, Bio processing, Process Integration

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Small biorefineries

Geoff Covey, Gerke Faber and Reg Harvey

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SUMMARY

At present, biorefineries are not economic unless very large, receiving government subsidies or in special circumstances. Building a large biorefinery presents technical and economic risks which are unacceptable to most companies. However, many organisations would like to gain an entry to the market for strategic reasons. If a high-value, low-volume by-product can be produced, the economics can be greatly improved and comparatively small operations can be worthwhile. This paper describes technology that is already in use to extract high value products from certain biomass types prior to their conversion to fuels.
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Deposit formation in the sulphite stage of a magnefite chemical recovery system

Ian Hamilton, Robert Adrien, Daniel Baer, Geoff Covey,
Dennis Creasy and Steven Harper

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ABSTRACT

A laboratory method has been developed which can reproduce the most important factors in the depositformation in the sulphite stage of a magnefite chemical recovery system. By adjusting conditions it is possible toproduce: scale-free operation, formation of free granules (‘sugar’), or severe scaling. The apparatus can also be used to study or confirm the effects of adding dispersants, changing operating temperature, and changing gas composition.

It was found that the presence of magnesium sulphite hexa-hydrate is a sign of conditions likely to result in fouling. The causes of fouling are complex and are dependent on temperature, organics in the distillate, operating pH, sulphur dioxide concentration in the gas in the mono-sulphite section, and (possibly) inorganic impurities in the magnesia. As such, it is unlikely that a full understanding ofthe process can be obtained at a satisfactory cost. HOWEVER, results to date strongly indicate that some comparatively simple and inexpensive adjustments to plantoperation could greatly reduce the severity of the fouling problem. Figure 2. Build up of fouling on a vessel wall.

Keywords scaling, magnesium sulphite, crystallisation
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