Process simulation spreadsheet models

Process simulation software can also be used to help build simple energy balances in spreadsheet models, for example, by entering stream data to calculate mixture heat capacities, to calculate stream enthalpies, or to estimate heats of reaction. 

Selecting the appropriate thermodynamic model and supplying correct parameters is a key step in solving a simulation problem. The purpose of this chapter is to review the fundamentals of phase equilibria in process simulation. Modem thermodynamic methods make possible the treatment of very complex mixtures, including supercritical and subcritical components, hydrocarbons or polar species, water, etc. Such calculations are impossible by hand or even with spreadsheets. However, the user should be aware that only a good understanding of theoretical bases could ensure reliable results. 

Once the calibrated simulation model is available, simulations can be re-run and equipment rating studies can be performed to identify equipment limitations and to generate many options to meet the revamp objectives. Spreadsheet and vendor models are also required to perform conceptual design and options. Heat and material balances, and preliminary equipment sizes, are estimated. Detailed process simulations, block flow diagrams, PFD, pipe and process equipment sizes are generated for each revamp design option these are useful for detailed analysis of benefits/constraints and CAPEX estimation for each option. 

BIOSCREEN (Newell et al., 1996) is an easy-to-use screening model that simulates remediation through natural attenuation (RNA) of dissolved hydrocarbons at petroleum fuel release sites. The software, programmed in a spreadsheet environment and based on the Domenico analytical solute transport model, has the ability to simulate advection, dispersion, adsorption, and aerobic decay as well as anaerobic reactions that have been shown to be the dominant biodegradation processes at many petroleum release sites. 

The BUSES model was developed to support the risk assessment of chemicals under various regulations. BUSES is a spreadsheet-based tool that incorporates SimpleBox, a multimedia fate model, and SimpleTreat, which simulates the distribution and elimination of chemicals in sewage freafment plants. The model estimates the concentrations of a substance in air, water, soil, and sediment at local and regional scales. It simulates the steady-state transport of chemicals between media and scales, and removal of the chemical by degradation and some "disappearance processes" (e.g., leaching to the groundwater, which is not then modeled) [106,107]. 

---