Mass and Energy Balance
6 weeks · 0 milestones
Perform a complete mass and energy balance for a real or representative chemical process, demonstrating conservation of mass and energy across each unit operation and the overall system. The balance must include: a process description identifying all feed streams, products, by-products, and waste streams, a mass balance table with inlet and outlet flows for all components (in consistent units) demonstrating closure within 1% or documenting any unaccounted losses, an energy balance covering the major energy inputs and outputs (heat of reaction, heat exchange, pump or compressor work) with documented thermodynamic data sources, and a stream summary table presenting all stream compositions, flowrates, temperatures, and pressures. Preferred proof: a mass and energy balance for a real industrial process using professional process simulation software. Accessible alternative: DWSIM (free, open-source chemical process simulator for Windows, Mac, and Linux) — simulation input file submitted alongside the results; OR a complete hand calculation for a simplified 2-3 unit process with documented data sources (NIST Chemistry WebBook for thermodynamic data — free). Proof artifacts: the process flowsheet with stream data (design artifact) and the balance tables demonstrating mass and energy closure (analysis artifact). Verification: a process engineer reviews the energy balance — 'your heat exchanger duty — what driving temperature difference are you assuming, and is that physically achievable given your stream temperatures?' — requiring you to reason from your own streams.
Milestone map
Milestone map
3 milestones
Select a real or simulated chemical process — distillation column, heat exchanger network, reaction system, or separation train. Define system boundaries clearly: which streams cross the boundary, which unit operations are inside it. Draw a process flow diagram (PFD) with all streams labelled. Proper system definition prevents the most common mass balance error: accounting for streams that should be outside the boundary.
Proof required
Submit your system definition document: the process you selected (real or simulated), a drawn PFD with all stream labels, and a list of all streams crossing the system boundary with their known and unknown compositions/flow rates.
What gets checked
- PFD is drawn (not copied from a textbook) with every stream numbered and every unit operation named
- System boundary is marked on the PFD as a dashed line with all crossing streams explicitly listed
- Degree-of-freedom table is completed and shows zero degrees of freedom (system is fully determined)