Process Design Basis

To reduce the potential for large releases of hazardous materials  

When dealing with flammable materials, the selection from the inherently safer design options may vary according to the site and process. For example, 

Although many engineers provide only the minimum adequate vessel design to minimize costs, it is inherently safer to minimize the use of safety interlocks and administrative controls by designing robust equipment. Passive hardware devices can be substituted for active control systems. For example, if the design pressure of the vessel system is higher than the maximum expected pressure, an interlock to trip the system on high pressure or temperatures may be unnecessary. 

Creating a strong system that constitutes a passive design requires a complete knowledge and characterization of the potential overpressure scenarios. This requires knowledge of the chemistry outside the design conditions to evaluate effects of loss of utilities and the loss of control systems. 

A passive design must include all hardware elements of the system. Little is gained if containment is lost when pipes, joints, or instruments fail due to overpressure. 

---

Chart I. Heavy-Oil Evaporation Dehydrator (HOE V-3) Process Design Basis ... 

Since we are now sizing the column, the first step is to increase the flow rate to allow for a design factor. The process design basis is 225 metric tons per hour of feed. The equipment design should include at least a 10% safety factor, so the equipment design basis was set at 250 metric tons per hour of feed (rounding up from 247.5 for convenience). 

Has the process design basis been documented or updated Has the control philosophy and sequence of operations been documented ... 

Process Design Basis and Process Scoping Studies, Among the numerous DPOM data, the work done by Gesser et al. was most extensive, gave the most optimistic results, and therefore was adopted for this study. Highlights of their work are ... 

The material balance and composition information which has been developed should now be tabulated into a process design basis for ready reference in later calculations. 

Process Design and Machinery. Following the field work of geologists and mining engineers and analyses (assays) to estabhsh the grades (concentrations) of values in ores, a mineral concentration flow sheet is estabhshed on the basis of a number of preliminary tests. These include studies of... 

P. A. Gupte, M. Nagvekar, R. P. Danner, and T. E. Daubert, Documentation of the Basis for Selection of the Contents of Chapters Phase Equilibrium in Manualfor Predicting Chemical Process Design Data, Design Institute for Physical Property Data (AIChE), (1987). 

While process design and equipment specification are usually performed prior to the implementation of the process, optimization of operating conditions is carried out monthly, weekly, daily, hourly, or even eveiy minute. Optimization of plant operations determines the set points for each unit at the temperatures, pressures, and flow rates that are the best in some sense. For example, the selection of the percentage of excess air in a process heater is quite critical and involves a balance on the fuel-air ratio to assure complete combustion and at the same time make the maximum use of the Heating potential of the fuel. Typical day-to-day optimization in a plant minimizes steam consumption or cooling water consumption, optimizes the reflux ratio in a distillation column, or allocates raw materials on an economic basis [Latour, Hydro Proc., 58(6), 73, 1979, and Hydro. Proc., 58(7), 219, 1979]. 

Dr. Coker has authored Fortran Programs for Chemical Process Design, Analysis and Simulation, and written a topie seetion in the Encyclopedia of Chemical Processing and Design (Vol. 61). He has direeted and eondueted short eourses for Proeter Gamble in the U.K., Saudi Basie Industries Corporation (SABIC) and Saudi Arameo Shell Refinery Company (SASREE) in Saudi Arabia. His artieles have been published in several international journals. 

A primary objective of any safety program is to maintain or reduce the level of risk in the process. The design basis, especially inherently safer features that are built into the installation, must be documented. Management of change programs must preserve and keep the base record current and protect against elimination of inherently safer features. For identical substitution, the level of risk in the process is... 

The analyses of system failures which could challenge the containment or lead to the release of radioactivity form the licensing process. The design basis analyses are deterministic, and degraded core accidents are not considered. PSA determines the probabilities of the numerous sequences that could lead to core degradation and how the core behaves. 

Another expansion of initial PSM installation is in implementing more demanding requirements. Your initial PSM design was derived from a "design basis" that included such considerations as a frequency for updating process... 

Fp) = Friction pressure loss (total) at design basis, for a system, psi, for process equipment and piping, but excluding the control valve... 

An adiabatic process is never fully attained but can be closely approached for many processes and is the primary design basis for most positive displacement compression equipment. 

---