Elements and Performance Criteria

This competency unit includes the mass transfer into and out of all processing equipment and requires the quantitative determination of mass transfer loads. This competency applies to all sectors within the chemical, hydrocarbons and oil refining industry.

Mass transfer modes include:
simple (physical) mixing
simple (physical) separation
changes in component mass flow rates due to chemical reaction (including mixing and separation using chemical reaction).

Assessment context and methods
Assessment for this unit of competency will be on an operating plant. The unit will be assessed in as holistic a manner as is practical and may be integrated with the assessment of other relevant units of competency.

Assessment will typically be by a mass balance project(s).

This unit of competency requires a significant body of knowledge, which will be assessed through questioning and the use of what if scenarios both on the plant and off the plant.

Critical aspects
Competence must be demonstrated in the ability to complete a mass balance in a structured way, taking real data from an operating plant.

Consistent performance should be demonstrated. In particular look to see that:
realistic boundaries are drawn for the mass balance which align with practical sources of data from the plant
data is collected from the plant with minimum disruption to production
theoretical and practical requirements for the mass balance are consistent
the mass balance data is used to identify and contribute to solutions for plant problems.

This will typically be assessed by one or more mass balance projects on an operating plant. One complex mass balance, or a number of simple mass balances, are required to demonstrate competence.

Resource implications
Assessment will require access to an operating plant over an extended period of time, or a suitable method of gathering evidence of operating ability over a range of situations. A bank of scenarios/case studies/what ifs will be required as will a bank of questions. which will be used to probe the reasoning behind the observable actions.

Other assessment advice
In all plants it may be appropriate to assess this unit concurrently with relevant teamwork and communication units.

Essential knowledge
Knowledge and understanding of mass transfer principles and calculations sufficient to determine the mass transfer loads of an existing or a new process. Competence includes the ability for the practical completion of the job to apply and/or explain:
changes in density with temperature (and pressure where appropriate)
stoichiometry of chemical reactions
mass balances.