Massbilanss

Massbilanss is a term used to describe the systematic accounting of all mass flows into and out of a defined system, ensuring that mass is conserved over time. The term combines 'mass' and the root of 'bilanz' (balance) in Germanic languages; in English literature the concept is usually referred to as mass balance or material balance.

In a massbilanss, the change in stored mass within the system equals the total input and generation minus the total output and consumption. For a steady state, storage change is zero, so inputs and generation equal outputs and consumption.

Typical workflow: delineate system boundaries, identify all inflows and outflows, estimate generation or loss terms (e.g., chemical reactions, evaporation, decay), quantify masses, and apply balance equations. Use measurements, process models, and stoichiometric constraints. Validate with observed data and update as needed.

Applications include environmental engineering (wastewater mass balance, nutrient cycling), industrial process design (material accounting for reactors and separations), hydrology (stream and aquifer balances), and pharmacokinetics (drug mass in body compartments).

Limitations: complexity grows with number of streams, uncertain measurements, some reactions may alter mass via phase change without obvious capture, and transient behavior requires time-dependent formulation. The term Massbilanss is often used interchangeably with mass balance; precise terminology may vary by discipline.