Slurry spraying

It was apparent from the very earliest tests that control of thin moisture films on the surface of reactive particles was the key to success. The main three competing arrangements, as compared by Statnick et al. [4th Annual Pitt. Coal Conf. 1987)] involved slurry spray dryers, where lime and water were injected together, versus systems where the gas was humidified by water injection before or after injection of limey dry powder reagents. It turns out that there are tradeoffs among the costs of hardware, reagent, and water dispersion and reagent purchase and disposal. Systems where water evaporates in the presence of active particles are usually less expensive overall. 

Improved control devices now frequently installed on conventional coal-utility boilers drastically affect the quantity, chemical composition, and physical characteristics of fine-particles emitted to the atmosphere from these sources. We recently sampled fly-ash aerosols upstream and downstream from a modern lime-slurry, spray-tower system installed on a 430-Mw(e) coal utility boiler. Particulate samples were collected in situ on membrane filters and in University of Washington MKIII and MKV cascade impactors. The MKV impactor, operated at reduced pressure and with a cyclone preseparator, provided 13 discrete particle-size fractions with median diameters ranging from 0,07 to 20 pm with up to 6 of the fractions in the highly respirable submicron particle range. The concentrations of up to 35 elements and estimates of the size distributions of particles in each of the fly-ash fractions were determined by instrumental neutron activation analysis and by electron microscopy, respectively. Mechanisms of fine-particle formation and chemical enrichment in the flue-gas desulfurization system are discussed. 

In the production of corrugating medium, linerboard and other unbleached (Kraft) paperboard grades, starch is added as a slurry spray to the fiber mat on the paper-maker s wire.205 This procedure provides better starch retention in the sheet than the addition of dispersed starch to the stock. According to the position of the spray boom, starch can be forced into the sheet for strength gain or held on the surface for improved surface quality. 

Another approach uses chlorine monoxide and water to form a solution of HOC1, which is neutralized with a lime slurry, spray-dried, and granulated to yield a product containing 70 percent available chlorine.49... 

Zeta-process and conventionally calcined powders can be made flowable for rapid mold filling in automated isostatic pressing of thin-walled cylindrical tubes by the technique of slurry spray drying (S D). Here the calcined and milled precursor powder is dispersed in an aqueous slurry (i.e., a stable, high solids content, low viscosity suspension) prior to spray-drying into spherical agglomerates. 

Continuous liquid feed Liquid/slurry Spray Dispersion Atomizing... 

The number of gas-phase transfer units that exist in a given column design depends on a number of factors, including 1) slurry spray rate 2) droplet size and distribution 3) gas-phase residence time, which is controlled by the height of the spray zone 4) liquid... 

Figure 370. Top and side view of a typical slurry spray system ...

Four Falex disks were slurry sprayed with the enamel composition. These specimens will be used to obtain pin-on-disk baseline wear and friction data for the enamel composition. The enamel will be evaluated running against both ceramic and metallic counterfaces. 

Table 1 lists the wear coatings which have been under evaluation to this point in the program. Wear testing has been completed for almost all the air plasma sprayed (APS) chromium oxides, some of the high velocity oxy-fuel (HVOF) thermal sprayed materials and the slurry-sprayed silica-chromia-alumina (SCA). Microstructural characterization has been completed for all the coatings which have been wear tested. 

For the cathode, a mixture of strontium-doped lanthanum manganite (LSM) proved most suitable, and as the slurry spray process was not scalable to larger modules and production volumes, the screen printing process was chosen for the cathode fabrication [76]. 

Fluidized material Particulate solid Paste/slurry sprayed onto a bed of inert particles Slurry sprayed onto absorbent particles (e.g., silica gel, biomass, etc.)... 

In summary, the Y-Si-Al-O environment barrier coatings were fabricated on the surface of porous SijN4 substrate by slurry spray method. After sintered at I350"C, 1400 C and 1450°C, grey uniform and bubble-free coatings covered on the surface of substrates. 

Aqueous Carbonate Process, 606 Lime Slurry Spray Dryer Processes, 607 Duct Spray Dryer Process, 614 Gas Suspension Spray Dryer Process, 614 Spray Dryer Byproduct Disposal and Use, 615... 

A simplified flow diagram for a lime slurry spray dryer system is shown in Figure 7-34. This diagram represents the 100 MW Demonstration Plant on Units 6 and 7 of the Riverside Station of Northern States Power Conqiany. The plant was used for extensive testing of die effects of various operating variables on a large 46-fi diameter spray dryer absorber (Gutslke etal., 1983). 

Figure 7-34. Flow diagram of the Lime Slurry Spray Dryer Process as tested at the Riverside Station of Northern States Power Company. Gutslke etal., 1983 ...

Figure 7-35. SO2 removal by the Lime Slurry Spray Dryer Process as a function of stoichiometric ratio and approach temperature. (Gu lke eta ., 1983i...

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