Spray temperature, concentration

Porofore concentration does not determine the yield of microspheres as much as the spraying temperature. In particular, the best choice of entry and chamber temperatures are 480 and 220 °C, respectively (Table 2) 28). 

Temperature, Concentration, and Velocity Measurements in Fuel Spray Free Flames... 

Measurements have been made of the combustion characteristics of an air blast kerosene spray flame and of droplet sizes within the spray boundary of isothermal sprays. Specific techniques were used to measure velocity, temperature, concentration, and droplet size. Velocities measured by laser anemometer in spray flames in some areas are 400% higher than those in isothermal sprays. Temperature profiles are similar to those of gaseous diffusion flames. Gas analyses indicate the formation of intermediate reactants, e.g., CO and Hg, in the cracking process. Rosin-Rammler mean size and size distribution of droplets in isothermal sprays are related to atomizer efficiency and subsequent secondary atomizer/vaporization effects. 

Spray drying involves converting the atomized liquid droplets into dry powders by hot air. This one-step process is capable of making particles of size suitable for inhalation.The particle size and size distribution of the powder can be manipulated by the concentration of the feed solution, the spray temperature, cyclone efficiency, and chemical nature of the feed. ... 

Liquid material of 4000 kg/h flow rate is initially at a solid mass content of 13% and a temperature of 3°C. It needs to be concentrated to a solid content (mass concentration) of about 57% before it is sent to a spray dryer. Material density is 720 kg/m at initial temperature. Concentration process needs to be performed at around atmospheric pressure. Specific heat of the material without moisture... 

In spray crystalliz/ation (prilling) [7.2] hot, high temperature concentrated solutions or melts are dispersed in a tower by means of nozzles or atomizer discs into a cold air flow, wherein crystallization heat is removed by direct phase contact. If the crystallization starts after droplets are formed, smooth spherical particles, prills result, otherwise irregularly shaped products with a partial crystalline or amorphous structure are formed at high cooling rate and evaporation rate. 

We have surveyed a series of different catalyst types under relatively standard ethylation conditions. Ethylation of cellulose can be conducted in a two stage process, which involves a recharge of caustic and ethyl chloride and a temperature increase when the D.S. reaches 1.4. Wood cellulose was treated with a fine spray of concentrated catalyst solution followed by hot 50% caustic. The mixture was either heated in toluene or dry-blended to produce the activated cellulose, which was charged into a bomb reactor along with additional sodium hydroxide and ethyl chloride. The reactor was immersed in a fluidized bed preheated to the desired temperature, and the bath temperature was held within a five degree range during the course of the reaction. 

The rate of spray is deterrnined by propellant concentration, the solvent used, and valve and vapor pressure. The pressure must be high enough to dehver the product at the desired rate under the required operating conditions. For example, a windshield ice remover that is likely to be used around 0°C must be formulated to provide an adequate pressure at that temperature. Spray dryness or wetness and droplet size depend upon propellant concentration. 

The speed of the pickle reaction is also dependent on the concentration and temperature of the pickle, the degree of agitation of either the metal part or the pickle solution, the alloy being pickled, and the acid used. Pickling solutions may be appHed by either spray or immersion techniques. However, because of the noxious fumes emitted, there must be adequate ventilation. Sometimes, particularly when spraying techniques are used, an enclosure to contain the fumes and mist is employed. 

Thermal decomposition of spent acids, eg, sulfuric acid, is required as an intermediate step at temperatures sufficientiy high to completely consume the organic contaminants by combustion temperatures above 1000°C are required. Concentrated acid can be made from the sulfur oxides. Spent acid is sprayed into a vertical combustion chamber, where the energy required to heat and vaporize the feed and support these endothermic reactions is suppHed by complete combustion of fuel oil plus added sulfur, if further acid production is desired. High feed rates of up to 30 t/d of uniform spent acid droplets are attained with a single rotary atomizer and decomposition rates of ca 400 t/d are possible (98). 

Pan and cascade burners are generally more limited ia flexibiHty and are useful only where low sulfur dioxide concentrations are desired. Gases from sulfur burners also contain small amounts of sulfur trioxide, hence the moisture content of the air used can be important ia achieving a corrosion-free operation. Continuous operation at temperatures above the condensation poiat of the product gases is advisable where exposure to steel (qv) surfaces is iavolved. Pressure atomiziag-spray burners, which are particularly suitable when high capacities are needed, are offered by the designers of sulfuric acid plants. 

Conventional nitrocellulose lacquer finishing leads to the emission of large quantities of solvents into the atmosphere. An ingeneous approach to reducing VOC emissions is the use of supercritical carbon dioxide as a component of the solvent mixture (172). The critical temperature and pressure of CO2 are 31.3°C and 7.4 MPa (72.9 atm), respectively. Below that temperature and above that pressure, CO2 is a supercritical fluid. It has been found that under these conditions, the solvency properties of CO2 ate similar to aromatic hydrocarbons (see Supercritical fluids). The coating is shipped in a concentrated form, then metered with supercritical CO2 into a proportioning airless spray gun system in such a ratio as to reduce the viscosity to the level needed for proper atomization. VOC emission reductions of 50% or more are projected. 

Flame Types and Their Characteristics. There are two main types of flames diffusion and premixed. In diffusion flames, the fuel and oxidant are separately introduced and the rate of the overall process is determined by the mixing rate. Examples of diffusion flames include the flames associated with candles, matches, gaseous fuel jets, oil sprays, and large fires, whether accidental or otherwise. In premixed flames, fuel and oxidant are mixed thoroughly prior to combustion. A fundamental understanding of both flame types and their stmcture involves the determination of the dimensions of the various zones in the flame and the temperature, velocity, and species concentrations throughout the system. 

Fuels such as diesel and kerosene readily absorb hydrocarbon vapors, the total uptake and absorption rate depending on both chemical and physical factors. If a soluble test gas is introduced above a charged test oil the concentration of flammable test gas therefore decreases with time. Liquid mist and spray produced by charged liquid increase the absorption rate relative to a quiescent liquid surface. As discussed in A-5-4, absorption could lead to an underestimation of test gas MIE near the liquid surface unless the rate of test gas introduction is sufficiently high to offset the rate of removal. Table 3-8.1.2 shows solubilities of a selection of gases in a mineral-based transformer oil at ambient temperature and pressure [200]. 

Pollutant Loading Typical inlet concentrations to a wire-pipe ESP are 1 to 10 grams per cubic meter (g/m ) (0.5 to 5 gr/fl ). It is common to pretreat a waste stream, usually with a wet spray or scrubber, to bring the stream temperature and... 

When the pollutant loading is exeeptionally high or consists of relatively large particles (> 2 /tm), venturi scrubbers or spray chambers may be used to reduce the load on the ESP. Much larger particles (> 10 /tm) are controlled with mechanical collectors such as cyclones. Gas conditioning equipment to reduce both inlet concentration and gas temperature is occasionally used as part of the original design of wet ESPs (AWMA, 1992 Flynn, 1999). 

Factors may be classified as quantitative when they take particular values, e.g. concentration or temperature, or qualitative when their presence or absence is of interest. As mentioned previously, for an LC-MS experiment the factors could include the composition of the mobile phase employed, its pH and flow rate [3], the nature and concentration of any mobile-phase additive, e.g. buffer or ion-pair reagent, the make-up of the solution in which the sample is injected [4], the ionization technique, spray voltage for electrospray, nebulizer temperature for APCI, nebulizing gas pressure, mass spectrometer source temperature, cone voltage in the mass spectrometer source, and the nature and pressure of gas in the collision cell if MS-MS is employed. For quantification, the assessment of results is likely to be on the basis of the selectivity and sensitivity of the analysis, i.e. the chromatographic separation and the maximum production of molecular species or product ions if MS-MS is employed. 

One of the advanced concepts for capturing CO2 is an absorption process that utilizes dry regenerable sorbents. Pure sodium bicarbonate from Dongyang Chemical Company and spray-dried sorbents were used to examine the characteristics of CO2 reaction in a flue gas environment. The chemical characteristics were investigated in a fast fluidized reactor of 0.025 m i.d., and the effects of several variables on sorbent activity, including gas velocity (1.5 to 3.5 m/s), temperature (40 to 70 °C), and solid concentration (15 to 25 kg/m /s)], were examined in a fast fluidized-bed. Spray-dried Sorb NX30 showed fast kinetics in the fluidized reactor. 

The reactivities of spray-dried sorbents were examined in a fast fluidized bed. The reactor was operated at a carbonation temperature of 50 °C, and a gas velocity of 2 m/s with an initial sorbent inventory of 7 kg to compare CO2 concentration profiles in effluent gas for spray-dried Sorb NH series and NX30 sorbent. Figure 5 shows the comparison of CO2 concentration profiles in effluent gas of Sorb NHR, NHR5, and NX30 in a fast fluidized-bed reactor. The CO2 removals of Sorb NHR and NHR5 were initially maintained at a level of 100 % for a short period of time and quickly dropped to a 10 to 20 % removal level. 

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