Control gas flow

Adiabatic. Control gas flow and/or solids feed rate so that the heat of reaction is removed as sensible heat in off gases and solids or heat supphed by gases or solids. 

Permeability Bulk sohd permeability is important in the iron and steel industiy where gas-solid reactions occur in the sinter plant and blast furnace. It also strongly influences compac tion processes where entrapped gas can impede compaction, and solids-handling equipment where restricted gas flow can impede product flowabihty. The permeabihty of a granular bed is inferred from measured pressure drop under controlled gas-flow conditions. 

A balanced valve employed to control gas flow in gas-fired boilers. Bypass damper ... 

The gas metering section is designed to deliver controlled gas flows of C3H6 (Praxair, 99.99%), 02 (Praxair, 99.998%) and He (Praxair, 99.999%) to the reactor system via Brooks 5850 mass flow controllers at a total flow rate 40 ml/min. and latm pressure. Feed gas compositions are C3H6 (40%), 02 (10%) and He (50%) for the steady state reaction. Prior to each experiment, the catalyst was reduced in pure flowing H2 at 34 ml/min for 2 hours at 400 °C. 

C for 10-14 h in an alumina tray inside a Lindberg tube furnace under controlled gas flow. On some occasions, and as a control experiment, pure argon gas was employed during the annealing step. Resultant powders were used in electrochemical (coin cell cycling) studies. 

The sensoric principle of the dynamic bubble-pressure tensiometer is based on the differential Laplace pressure between two capillaries from which a controlled gas flow is released. At the lower end of a capillary which points into the liquid, a gas bubble is formed which increases its radius with increasing gas pressure (see... 

Mixing. Mixing can be accomplished by mechanical recirculation, agitation or by controlled gas flow methods. The practice is desired to facilitate on intimate contact between methane forming bacteria and their substrate and to prevent the formation of surface scum in the digester. 

When working with apparatus such as catalytic flow reactors, the measurement and control of gas flow becomes as important as the measurement of pressure just described for vacuum line work. Some of the more common methods for measuring and controlling gas flow in gas-handling systems will now be discussed. 

Fig. 8.9. Notched stopcock plug. A triangular file drawn across the orifice at right angles to the length of the plug will notch the orifice. This may then be used to better control gas flow, such as an inert-gas flow while working on a Schlenk manifold.

A number of sensor arrays consisting of an assortment of commercial metal oxide gas sensors have been reported [45 7], For controlled tests, the sensors are mounted in an air-tight chamber fitted with gas inlets and outlets for controlled gas flow. Each sensor s heating element is controlled externally and resistance changes of the gas sensors are monitored by a computer data acquisition system. A significant effort in this area exists at the University of Warwick, Coventry, where for many years, sensor arrays, made from discrete Sn02 sensors or miniature integrated sensors, have been studied for ultimate application to food quality and food process control [47, 48]. 

An essential feature of this new design is a better controlled gas flow pattern in the coating zone. This is achieved by application of a guiding system in which the gas flow is accelerated, stabilized, and given a precise amount of swirl, which eliminates slugging, often seen in traditional coaters, and stabilizes multi-tube systems. Particles are... 

The second indirect method is by measurement of the weight of ethylene oxide delivered from the feed containers to the sterilizer. This method assumes no leakage, liquefaction, or polymerization of ethylene oxide in the gas tines connecting the gas source to the sterilizer. It is recommended that the two indirect methods be used in conjunction with each other. The weight loss method ensures that the increase in pressure is in fact due to gas from the ethylene oxide feed container and not from diluent gas or some other source whereas the pressure method provides an ongoing index of gas concentration during the exposure period. Gas makeups should be automated and specified to be drawn from the ethylene oxide feed tanks, not from the diluent gas. Gas makeup may be controlled by pressure switches or by pressure transducers connected to solenoid valves controlling gas flow. 

Fluidization of the uncoated support material by means of a temperature-controlled gas flow, such as air, nitrogen, or argon, is followed by addition of a solution of catalyst and IL, sprayed onto the material through a nozzle shown in detail in Figure 4.7(b). The molecular solvent evaporates rapidly because of the gas flow, resulting in a good dispersion of the ionic catalyst solution onto the support... 

Metler-Toledo RT-1100°C 10, 0.0013 lOnm 20 mm Controlled gas flow, reactive gas capability... 

TA Instruments TMA 0400 -150-1000°C 2,0.001 15 nm 26 mm Modulated TMA (see next section), controlled gas flow, reactive gas capabihty, additional probes compression, shear, parallel plate, single/dual cantilever... 

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