Air/gas flow

It is important to keep bolts, nuts and other potentially loose items to a minimum inside the unit, as vibration from air/gas flow and bag cleaning can loosen nuts, break small welds, and ultimately tear holes or rip bags. The bag construction is likewise extremely important, since loose edges and unlocked seams will fray and tear, allowing fibers into the product dust. The bag construction must have straight seams in order for them to bend and flex properly on cleaning and/or loading. 

The degree of development of liquid and air (gas) flows inside an atomizer governs the velocity profiles and turbulence levels at thenozzle... 

Air (gas) flow rate Obviously gas flows are another important parameter for proper dryer operation. Pitot tubes are useful when a system has no permanent gas flow sensors. Averaging pitot tubes work well in permanent installations. The devices work best in straight sections of ductwork which are sometimes difficult to find and make accurate measurement a challenge. 

Figure 9,8 Mean air (gas) flow rate vs dimensionsless time. Range of = 0.6-30 [Purchas and Wakeman,1986]...

The most important variables in the process are the air gas ratio, the air/gas flow rate, the namre of the gas, the burner-surface separation and the exposure time. The gas used is either mains (mainly methane) or bottled (propane or butane). For optimum treatment, an oxidizing flame should be used, that is, with an excess of oxygen over that required for complete combustion. For a given air gas ratio, treatment level in a given exposure time increases as the volume of mixture burned increases. It is clearly important that the exposure time is not sufficient for the surface polymer to melt (the flame temperature is 2000 °C) in the case of film treatment, the film is treated as it passes over a cooled roll. 

Marin et al. (2010) smdied butane oxidation to maleic anhydride in a fixed-bed membrane reactor and compared the results with a fixed-bed reactor with the same production capacity. The results showed that with an increase in the length of the reactor, the temperature of the inlet gas, and the rate of air gas flow, and a decrease in the butane/nitrogen flow rate and the butane concentration, the butane concentration would enhance. Although in the membrane reactor, the selectivity was only slightly higher than that of a conventional one, it could be a good choice for butane oxidation because it allows higher butane inlet concentration. 

After the sharp drop in the mass via temperature curve due to polyethylene pyrolysis, the remaining mass does not usually remain constant with temperature. Rather, the curve continues to gradually decrease. The point of time or temperature for switching over to synthetic air gas flow can therefore affect the measurement result of the carbon black content. Such measurement conditions must be observed to achieve comparable results. Comparing the measurement results with measurements obtained by con-... 

The hot S02/air gas flows through the stainless steel 316 inner pipe and the ambient cooling air through the mild steel outer pipe. The first part of the hairpin cooler is used to preheat the dried process air before it enters the top of the sulphur burner. The Chemiton SOs/air-ambient cooler is a simple single horizontal hairpin double-tube heat exchanger. 

After preheating of the plant and initial sulphur burning, the conversion to SO3 will increase gradually with time. It takes about 0.5 hour before the conversion attains the desired level of 98-98.5%. During this period it is not possible to produce good quality organic acid product and therefore the SOj/SOj/air gas flow has to be diverted, without inftinging the limits on SO2/SO3 levels in the exhaust gas that are emitted to the atmosphere. 

Membrane Technology, Fig. 2 Oxygen-permeation flux through a ceramic membrane (schematically). Gas flow 1 is of high oxygen pressure (air), gas flow 2 is vacuum or methane... 

Air/gas flow sensor for synchronization of scanning with breathing. 

Commonly used online controls in industrial fermentations are the control of temperature, pressure, dissolved oxygen, and pH. Additional parameters to be controlled may be air/gas flow, feeding of substrates and supplements, or in situ product-recovery-related parameters (see Figure 1.6). Quantitative determination of the off-gas composition may further support control of the process. Complex and elaborate online measurements and controls should be avoided in an industrial production setting, although they can be useful during laboratory- or pilot-scale process development. 

As discussed in detail by Briggs [35], although flame treatment has been applied to polyolefin films, it is now mainly used to pretreat thicker section components such as blow-moulded bottles. The increased adhesion that results enables the bottles to be successfully ink-printed. The component to be treated is passed over one or more burners, each burner consisting of a large number of closely spaced jets the burners are fed with an air-gas mixture in controlled proportions and the gas can be from the mains (largely methane) or bottled (propane or butane). Typically the component spends about 1 s, or less, in the flame. The most important variables are the position of the component relative to the flame the airrgas ratio the air/gas flow rate the nature of the gas the burner-surface separation and the exposure time. 

There are two velocities which compose the shape and treatment efficacy of either ribbon or EV flame burners - the velocity of the air/gas flow to/from the burner, and the formed velocity of the flame itself. The optimization and control of these velocities emanates from the design of the combustion system and burner ports. Penetration of the boundary layer of air, which flows above the web surface at high process speeds, is integral to designed burner output velocities. 

---