Optimization of Palm Oil Processing Parameters to Improve Crude Palm Oil Yield and Energy Efficiency

Abstract

Crude palm oil yield and mill energy consumption are conventionally managed as separate objectives, yet both are governed by the same set of controllable process parameters, so that improvements pursued independently frequently cancel one another. This paper reviews the parametric basis of palm oil milling and establishes where oil recovery and energy demand are coupled, where they are independent, and where a genuine trade-off exists. A structured review was conducted on peer-reviewed studies indexed in Scopus and SINTA published between 2010 and 2025, covering sterilization, threshing, digestion, pressing, clarification, and the mill utility system. Retained studies were coded for the unit operation examined, the parameters manipulated, the response measured, and the direction of the reported effect, and were then organised into a parameter-response matrix. The synthesis shows that sterilization is the dominant coupling point, since the same steam input that determines enzyme deactivation and bunch loosening also constitutes the largest single thermal load in the mill, while pressing and clarification affect oil recovery with comparatively little energy consequence. Evidence from mill-scale energy studies indicates that the milling process requires in the order of fifteen to twenty kilowatts and five hundred to seven hundred kilograms of steam per tonne of fresh fruit bunches, and that recovering vented sterilization steam and engine waste heat materially increases surplus power. The paper argues that parameter optimization should be formulated as a constrained multi-objective problem anchored on sterilization, and proposes a staged measurement protocol that mills can implement before committing capital to equipment change.