Emission Calculations and Reporting
SuperPro and EnviroPro Designer estimate emissions of regulated and other compounds from manufacturing operations (primary emissions) and end-of-pipe treatment processes (secondary emissions). They do not estimate fugitive emissions (e.g., from pipe cracks, pump flanges, etc.), but those can be readily represented (if you have some other way of estimating them) using component splitters and generic boxes or even calculated using user-defined models.
The figure below shows the classification of emitted compounds (this is component-specific information). Emissions from an entire manufacturing facility for all these pollutant categories are provided in the “Emissions Report”.
SuperPro and EnviroPro Designer perform volatile organic compound (VOC) emission calculations for several batch operations that are common in the pharmaceutical and specialty chemical industries. Further, they enable users to specify and track emissions of particulate and other regulated compounds for which no mathematical models are available. The VOC emission models are based on EPA guidelines (OAQPS, Control of Volatile Organic Emissions from Manufacture of Synthesized Pharmaceutical Products, EPA-450/2-78-029, December 1978 and OAQPS, Control of Volatile Organic Compound Emissions from Batch Processes, EPA-453/R-94-020, February 1994). Emission models are available for the following operations:
- Displacement (i.e. Charge, Transfer In)
- Evacuation / Depressuring
- Gas Sweep
- Gas Evolution
- Operation under Vacuum
A detailed description of the emission mathematical models can be found in the Help Facility of SuperPro and EnviroPro Designer. The Help Facility can be downloaded along with the Evaluation version of SuperPro.
SuperPro and EnviroPro Designer are equipped with rigorous models for calculating VOC emissions from wastewater treatment plants. There are four types of emission calculation models in the current version of the software. The first type includes emissions from tanks and basins with quiescent surfaces (e.g., equalizers, neutralizers, clarifiers, thickeners, flotation, and oil separation units). The removal of VOCs from tanks with quiescent surfaces occurs due to natural volatilization, i.e., mass transfer across open surfaces. The second type includes emissions from aerated tanks equipped with surface or diffused aeration systems. The removal of VOCs from such tanks occurs due to surface volatilization for mechanically aerated systems or due to stripping for tanks with diffused aeration systems. The third type includes emissions from trickling filters. Trickling filters are modeled as packed-media systems in which volatilization is the primary removal mechanism for all VOCs, a conservative assumption for VOCs that are biodegradable. Finally, the fourth type includes emission calculation models for junction boxes. Junction boxes combine wastewater streams flowing into a treatment plant. These boxes are usually open to the atmosphere and VOC emissions occur in a similar manner as emissions from quiescent surface tanks.A detailed description of the emission mathematical models can be found in the Help Facility of SuperPro and EnviroPro Designer. The Help Facility can be downloaded along with the Evaluation version of SuperPro.
Initialization of Emission Models
The operations that perform emission calculations include an “Emissions” tab on their input/output dialog window. The figure below shows the Emissions tab of Aerobic BioOxidation. The user identifies the components for which the model should perform emission calculations and may optionally specify parameters (through the Emission Model dialog) that affect those calculations. The user also has the option to specify the “Emission %” of a component.
The following table is from the Emissions report that the software generates. The program reports emissions from each unit procedures (processing step) in kg/h. If the procedure operates in batch or semi-continuous mode, the rate in kg/h is calculated by dividing the amount of emissions per cycle divided by the cycle time of the unit procedure. The report also provides info on total emissions per batch (or per hour for continuous processes) and per year.