Based on physics and chemistry’s conservation of mass law, mass can be neither created nor destroyed. Mass balance is:
The mass that enters a system must, by conservation of mass, either leave the system or accumulate within the system.
I offer this as background for my communications with Emerson’s Martin McDonough, who shared with me its use in chemical plant losses and production accounting. The gain or loss is determined by the open inventory plus receipts minus shipments, closing inventory, and fuel consumed. This gain or loss can be accountable or unaccountable. Production accounting is the mass balance plus data reconciliation.
Accuracy in mass balance calculations affects profitability, health/safety/environment, and process optimization. Accuracy in the measurements means not overpaying or getting underpaid on feedstocks and correctly paying on the custody transfer of produced productions. The measurements enable accurate emissions and energy intensity index (EII) reporting. In process optimization, they help to pinpoint losses earlier, minimize unaccounted losses, and provide regulatory and advanced control strategies to optimize production performance.
Essential measurements for effective production accounting include mass flow for custody transfer measurements for feedstocks and final products, density measurements to improve the accuracy of volumetric measurements, tank gauging for accurate level measurements, and pressure relief monitoring for identification and correction in relief events.
Here is a view of some measurements that can improve your operational performance.
Some of the Emerson measurement devices that can help provide reliable and accurate data from key material streams include:
- Micro Motion Coriolis mass flow meters
- Rosemount 3051S MultiVariable flow transmitters
- Micro Motion GDM gas density meters and CDM compact liquid density meters
- Rosemount 5900S radar level gauge, 2410 tank hub, 2240S multi-input temperature transmitter with 565 multiple spot temperature sensor
- Rosemount 3308 wireless level transmitter, 5302 guided wave radar level transmitter, 5804 non-contacting radar level transmitter
- Rosemount 708 wireless acoustic transmitter, Plantweb Insight Pressure Relief Valve application
- Aspen Unified Reconciliation and Accounting (AURA) software
For more on ways to improve overall mass balance with improved measurement integrity visit the Solutions to Optimize Your Chemical Plant Performance page on Emerson.com and download the Mass Balance document. You can also speak directly with Martin by arranging a time here.
