Stoffstrom

Stoffstrom, in German, denotes the flow of materials or substances through a system. It is a core concept in fields such as process engineering, chemical engineering and environmental science, where it describes how matter moves across the boundaries of a unit, plant, or region. A Stoffstrom can refer to a single stream of material or to the network of interconnected streams that constitute a system.

In process engineering, Stoffströme are characterized by a flow rate and a composition. The mass flow rate (for example kilograms per second) or molar flow rate (moles per second) specifies how much material passes a point per unit time, while the composition describes the amounts of each substance in the stream. The principle of mass balance requires that the sum of inflowing Stoffströme equals the sum of outflowing Stoffströme plus any accumulation within the system.

A Stoffstrom diagram, or material flow diagram, visually represents these streams with arrows whose width reflects magnitude and direction shows the flow through the system. Such diagrams support process design, optimization, and safety assessments, and they are widely used in chemical plants and in systems thinking.

In environmental science and industrial ecology, Stoffströme are used in Material Flow Analysis (MFA) to trace the movement of materials through an economy or region. This helps quantify resource use, emissions, and waste, and supports decisions on resource efficiency and circular economy strategies.

Measurement and data for Stoffströme come from instruments, process models, and external statistics. Standard practice combines measured flow rates with composition data to compute total stocks and flows, enabling mass balances and simulations of future scenarios.

Etymology and usage: Stoffstrom literally means material flow in German; the term is used mainly in German-speaking contexts, where Stoffströme (plural) is common.