Plant System Design

In the Jaakko Poyry MODE concept the process application is integrated with a 3D plant design system. All information between the systems is transferred in an application-independent XML format. Using the application server in integration gives possibilities to share design work in different locations within the company or even between different companies. Currently Poyry s own legacy XML schema is used, but when standard schemas are published, those should be used. 

EXHIBIT 17"6 Typical Plant Design System—Generated Instrument Loop Diagram... 

Detailed Engineering Model Using a Plant Design System... 

An extraction plant should operate at steady state in accordance with the flow-sheet design for the process. However, fluctuation in feed streams can cause changes in product quaUty unless a sophisticated system of feed-forward control is used (103). Upsets of operation caused by flooding in the column always force shutdowns. Therefore, interface control could be of utmost importance. The plant design should be based on (/) process control (qv) decisions made by trained technical personnel, (2) off-line analysis or limited on-line automatic analysis, and (J) control panels equipped with manual and automatic control for motor speed, flow, interface level, pressure, temperature, etc. 

For central station power generation the open cycle system using electrically conducting coal combustion products as the working fluid is employed. The fuel typically is pulverized coal burned directly in the MHD combustor, although in some plant designs cleaner fuels made from coal by gasification or by beneficiation have been considered (8—10) (see Fuels, synthetic). 

Defining the requirements for a pilot-plant control system is often difficult because process plant experience for comparison and evaluation is commonly lacking and the design is frequentiy performed by personnel inexperienced in either instmmentation systems or pilot-plant operations. The isolated and often intermittent nature of pilot-plant operations also inhibits evolution and promotes individual unique installations. This compHcates the selection process. 

The choice of a specific CO2 removal system depends on the overall ammonia plant design and process integration. Important considerations include CO2 sHp required, CO2 partial pressure in the synthesis gas, presence or lack of sulfur, process energy demands, investment cost, availabiUty of solvent, and CO2 recovery requirements. Carbon dioxide is normally recovered for use in the manufacture of urea, in the carbonated beverage industry, or for enhanced oil recovery by miscible flooding. 

Good design ideas for new plants are also good for existing plants, but there are three basic differences. (/) Because a plant already exists, the capital—operating cost curve differs. Usually, this makes it more difficult to reduce utiHty costs to as low a level as in a new plant. (2) The real economic justification for change is more likely to be obscured by the plant accounting system and other nontechnical inputs. (2) The real process needs are... 

Wachel, J. C., Consideration of Mechanical System Dynamics in Plant Design, ASME 67-DGP-5, New York, NY American Society of Mechanical Engineers, 1967. 

NOTE To develop reasonably good data for scale-up to full plant design, it is important to have the operation of the pilot column system as near as possible to the anticipated plant conditions. The most critical factors, flow rate and feed impurity concentration, must be constant for the entire test run. 

This section provides a detailed example of flare system specification. This is an example of a formal design document that would be provided by the plant designer to a flare system vendor. The reader should consider this section as an example of the types of information and level of detail needed in specifying the system, however the format and organization might certainly be changed to suit the particular needs of the plant operations. 

Humans require time to react to process alarms and control requirements. Reaction time must always be considered early in the plant design. It is inherently safer to decide early in process design what administrative controls the operator will be assigned to activate for safety control. Requiring periodic operator interface to the process system relieves boredom and heightens interest in knowing the current condition of the process. See Sections 6.4 and 6.5. 

Two studies resolved the Unresolved Safety Issue A-44, "Station Blackout." The first siudy, The Reliability of Emergency AC Power Systems in Nuclear Power Plants," when combined uh die lelevant loss-oToffsite-power frequency, provides estimates of station-blackout frequencies lor 18 nuclear power plants and 10 generic designs. The study also identified the design and operational features most important to the reliability of AC power systems. The second study, "Station Blackout Accident Analysis" (NUREG/CR-3226), focused on the relative importance to risk of laiion blackout events and the plant design and operational features that would reduce this risk. 

Plant design differences (primarily in support systems such as cooling water, electrical power, ventilation, and air systems)... 

Chemical plants require a well-engineered system for fire protection. Many of the basic fire protection facilities must be incorporated into the original plant design in order to achieve maximum effectiveness. Fire extinguishing facilities and equipment should include ... 

---