Multiple Trains

Multiple trains or skids placed in parallel are used when larger flow rates need to be treated. For example, an 800-gpm RO might require 1 skid, if the vendor has that size skid in their inventory. Alternatively, one could use two 400-gpm RO skids to make up the 800 gpm production rate. 

There is an advantage to using multiple skids in that multiple skids provide redundancy for the system one skid can still be on line while the other is off line for cleaning or maintenance. Additionally, multiple skids can be used to juggle variable product water demands. See Chapter 15.2 for more information about variable demands and multiple RO skids. 

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Gas and Hquid dehydrators employing molecular sieves provide product gas streams of <0.1 ppmv water and product Hquid streams routinely to <10 ppmv water. AppHcable pressures range from less than one to several hundred times atmospheric pressure. Temperatures range from subzero to several hundred °C. Processing units range in capacity from as Httle as 10 m /h to as much as 10 mr /d in multiple-train units. 

The total plant, whether single or multiple trains, should nonnally be of the established commercial maximum size. Otherwise, without maximum economy of scale, it will be difficult to compete in the marketplace. 

Process Conceptual Design Equipment selection and sizing Inventory of process Single vs. Multiple trains Utility requirements Overdesign and flexibility Recycles and buffer capacities Instrumentation and control Location of plant Preliminary plant layout Materials of construction As above plus equipment suppliers data, raw materials data, company design procedures and requirements... 

There is the need to phase out multiple trains in order to improve economics. 

Knowledge of the flow patterns for RO systems is fundamental to the understanding of how an RO system functions. Arrays, passes, recycle, and multiple trains are terms used to describe an RO system that are discussed in this chapter. 

As shown in Figure 2, flue gas from the boiler at about 300°F passes through a 95 efficient ESP to remove most of the fly ash before the flue gas enters the FGD system. The collected fly ash is removed from the ESP hopper, transferred to intermediate storage silos, and trucked to an onsite ash landfill situated one mile from the power unit. The flue gas from the ESP passes through the boiler ID fan, a common plenum feeding the multiple trains of spray dryers, and the ductwork feeding the spray dryer. 

The products from the two reactors can be combined and distilled in a single operation. This concept may have particular merit as GTL facilities expand and multiple trains are used. 

Prom Tkble 3.14 it can be taken that for train 1 a feasible RTC assignment is made while for train 2 the maximum total weight of 100 is exceeded. In case when multiple trains can be dispatched on a trip, a reformulation of (3.43) and (3.44) would overcome this problem. However, to reformulate both constraints additional variables are necessary indicating whether both constraints are (almost) restrictive for a specific trip. This would lead to a more complicated model. Since the problem only occurs if the total payload is close to its maximum, it suffices to introduce a safety buffer for the total train weight. 

American Red Cross Disaster Mental Health Services Multiple (Training, short-term intervention)... 

The Subway Environment Simulation (SES) Computer Program is a designer-oriented tool which provides, in any given multi-track subway operated by multiple trains, the continuous reading of the air velocity, pressure, temperature, and humidity throughout any arrangement of stations, tunnels, ventilation shafts, and fan shafts. The main capabilities of the SES... 

Another form of redundancy is the excess capacity often built into plants with more than one processing line. If two sets of drying towers are used, for example, the capacity of each may be more than 50% of the plant design capacity. The primary justification for multiple trains usually is to enhance turndown capability or to allow continued operation even when one train must be shut down. The same approach may be taken with the cooling section. Given the sizes of chlorine gas headers, valves would be expensive and probably ineffective as shutoff devices. Many plants therefore use U- or J-shaped traps in the piping. These can be filled with water or acid to stop the gas flow and to isolate equipment for maintenance. 

Backup supplies are always useful when a utility is lost Spare equipment or multiple-train equipment may be used in order to keep the utility on line even if one part of the system shuts down. An alternative or supplement is to provide backup from a different utility system. The number of different air systems found in a plant provides an opportunity to do this. Moreover, nitrogen can be used to back up some of the air systems. All these tie-ins require careful review during hazard analyses. Usually, the backup supply is activated when the primary supply loses a certain amount of line pressure. If this is done by means of a single pressure regulator and the pressure is also low on the backup system, the flow may be opposite to that intended. It is essential to keep nitrogen out of an air supply to a confined, inhabited space (e.g., the instrument air supply to a control room), and it is essential to keep air out of nitrogen when it is used as an inert gas. 

The objective function may take the form of the likelihood or posterior distribution functions [5]. It is pertinent to mention that maximization of the likelihood function in case of independent normally distributed errors leads to the sum-of-squares (SOS) of the residuals, such as given by equation (1). Another approach to fitting multiple training targets is to use multi-objective optimization, which is concerned with simultaneous optimization of a set of objectives. 

The type of electrolytic cell commonly used in these marine and offshore applications is a tube within a tube , (but there are a variety of configurations.) A tube within a tube type cell consists of one anode, one cathode, and one bipolar tube with the necessary ancillary hardware to facilitate assembly-see Fig. 1. The outer anode and cathode are manufactured firom seamless titanium pipe. The anode surface is coated with proprietary precious metal oxides, primarily ruthenium and iridium. Seawater enters one end of the cell and passes between the cathode, the anode and bipolar tube annular spaces. When direct current is applied to the cell, sodium hypochlorite results. One cell can produce up to 5.5 kg/day and a maximum of 12 cells can be connected in series for a capacity of 65 kg/day per train. Multiple trains can operate in parallel to produce the required capacity. 

MHFS Multiple train high-frequency stimulation... 

The simulation hospital is served through a sophisticated audiovisual system because of the multiple training sessions that are conducted simultaneously. Capturing these exercises is vital for the debriefing process. The number of cameras will depend on the size of the simulation hospital. A special area on each floor should be dedicated to the audiovisual technician, who needs to review and archive the videos another area is needed for the servers. Special consideration is given to temperature control in this room the temperature must be maintained between 15 °C and 18 °C at all times because of the excessive heat from the servers. 

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