Flame processes

Band theory Ban-Flame process Banked memory Banocide Bantu siderosis Barb an Barbased Barbital... 

Flame or Partial Combustion Processes. In the combustion or flame processes, the necessary energy is imparted to the feedstock by the partial combustion of the hydrocarbon feed (one-stage process), or by the combustion of residual gas, or any other suitable fuel, and subsequent injection of the cracking stock into the hot combustion gases (two-stage process). A detailed discussion of the kinetics for the pyrolysis of methane for the production of acetylene by partial oxidation, and some conclusions as to reaction mechanism have been given (12). 

Table 12. BASF Submerged-Flame Process-Average Cracked Gas Composition, ...

CP esters are generally prepared as the ammonium salt [9038-38-4] by the reaction of cellulose with phosphoric acid and urea at elevated temperatures (130—150°C). The effects of temperature and urea/H PO /cellulose composition on product analysis have been investigated (33). One of the first commercially feasible dameproofing procedures for cotton fabric, the Ban-Flame process (34,35), was based on this chemistry. It consists of mixing cellulose with a mixture of 50% urea, 18% H PO, and 32% water. It is then pressed to remove excess solution, heated to 150—175°C for 5—30 minutes, and thoroughly washed (36). 

No additional gaseous components that coming from gaseous heating source in the case of gas-flame process ... 

Flame spray pyrolysis (FSP) a liquid precursor solution is sprayed into the flame and ignites its combustion drives the flame process. 

Various methods are applied to the synthesis of titania particles including sol-gel method, hydrothermal method [2], citrate gel method, flame processing and spray pyrolysis [1]. To utilize titania as a photocatalyst, the formation of ultrafme anatase titania particles with large crystallite size and large surface area by various ways has been studied [4]. 

Another distinguishing feature of titania prepared by flame spray pyrolysis is the draar e of anatase crystallite size with the increase of flame temperature. Generally, the increase of preparation temperature increases the crystallite size in other processes such as sol-gel method, hydrothermal method [2, 3], flame processing and conventional spray pyrolysis. The decrease of crystallite size was directly related to the decrease of particle size. Fig. 5 shows SEM and TEM images of titania particles prepared by flame spray pyrolysis. 

Flame Processes—Theoretical and Experimental J. F. Wehner Bifunctional Catalysts J. H. Sinfelt... 

Recently, nanocomposites of calcium and bismuth mixed oxides obtained by flame synthesis were used for the degradation of organic dyes under visible light, with good activity due to the formation of relatively high surface area materials and oxygen vacancy formation in the flame process [119]. 

Instrumentation. Flame Characteristics. Flame Processes. Emission Spectra. Quantitative Measurements and Interferences. Applications of Flame Photometry and Flame Atomic Emission Spectrometry. 

Since diffusion rates vary with pressure and the rate of overall combustion reactions varies approximately with the pressure squared, at very low pressures the flame formed will exhibit premixed combustion characteristics even though the fuel and oxidizer may be separate concentric gaseous streams. Figure 6.1 details how the flame structure varies with pressure for such a configuration where the fuel is a simple higher-order hydrocarbon [1], Normally, the concentric fuel-oxidizer configuration is typical of diffusion flame processes. 

In order to calculate the thermal NO formation rate from the preceding expression, it is necessary to know the concentrations of 02, N2, O, and OH. But the characteristic time for the forward reaction (8.49) always exceeds the characteristic times for the reaction systems that make up the processes in fuel-oxidizer flame systems thus, it would appear possible to decouple the thermal NO process from the flame process. Using such an assumption, the NO formation can be calculated from Eq. (8.52) using local equilibrium values of temperature and concentrations of 02, N2, O, and OH. 

The silica produced from this reaction will have the particle size of approximately 300 A (during the flame process). Then the particles cool and fuse into aggregates in length, which is irreversible. In addition, because the silica crystallizes in gas phase, the particle shape tends to be irregular, as shown in Fig. 3a. 

Other techniques simulate postignition flame processes. In the flow reactor, reactants of interest enter the reactor at one end and travel through a constant temperature region. Ideally, all concentrations and temperatures are consistent across the cross section of the reactor, so that all movement is in one direction and wall reactions are minimized. A similar approach involves the use of crossed molecular beams, ° wherein two molecular beams are directed into one another the area of collisional intersection demonstrates chemistry that can occur in flames. 

The most important processes nowadays to produce acetylene are the partial-combustion technologies.358-360 They are flame processes and involve the combustion of the feedstock or the residual gas to yield the necessary energy to attain the required high temperature. Combined yields of acetylene and ethylene can reach 50% with an ethylene acetylene ratio of 0.1 3. 

T Talogen compounds promote slow combustion (1, 5, 11, 16, 17), and yet they strongly inhibit flame processes (4, 6, 7, 8, 10, 18). These effects have intrigued many investigators, but it is still not clear at what stage and how the effect changes from promotion to inhibition. 

These studies provide comprehensive information on the effects of many halogen compounds on the combustion behavior of various hydrocarbons. The combustion behavior included preflame oxidation, ignition over a wide range of temperature, and the flame process. The effect of iodine compounds on preflame combustion, which had not been previously investigated, is now reported. 

Figure 5.11. Schematic diagram of the basic flame processes in the FID.

---