Liquor black

Through the use of lab tests implemented by the pulp and paper companies in the United States and Canada it was determined that all but one manual technique were both unrepeatable and inaccurate. During some years ago the operators of black liquor recovery boilers have been able to take advantage of the latest teehnology to inspect the wall thickness of the near drum generator tubes. The technology utilises immersion ultrasound and automated computer... 

Black cyanide Black dross Black glasses Black liquor... 

Black Liquor Soap Recovery. Black Hquor soap consists of the sodium salts of the resin and fatty acids with small amounts of unsaponifiables. The soap is most easily separated from the black Hquor by skimming at an intermediate stage, when the black Hquor is evaporated to 25% soHds (7). At this soHds level, the soap rises in the skimmer at a rate of 0.76 m/h. At higher soHds concentrations, the tall oil soap is less soluble, but higher viscosity lowers the soap rise rate and increases the necessary residence times in the soap skimmer beyond 3—4 hours. The time required for soap recovery can be reduced by installing baffles, by the use of chemical flocculants (8,9), and by air injection into the suction side of the soap skimmer feed pump. Soap density is controUed by the rate of air injection. Optimum results (70% skimmer efficiency) are obtained at a soap density of 0.84 kg/L (7 lb/gal). This soap has a minimum residual black Hquor content of 15% (10—12). 

Black Liquor Soap Acidulation. Only two-thirds of a typical black Hquor soap consists of the sodium salts of fatty acids and resin acids (rosin). These acids are layered in a Hquid crystal fashion. In between these layers is black Hquor at the concentration of the soap skimmer, with various impurities, such as sodium carbonate, sodium sulfide, sodium sulfate, sodium hydroxide, sodium Hgnate, and calcium salts. This makes up the remaining one-third of the soap. Cmde tall oil is generated by acidifying the black Hquor soap with 30% sulfuric acid to a pH of 3. This is usually done in a vessel at 95°C with 20—30 minutes of vigorous agitation. Caution should be taken to scmb the hydrogen sulfide from the exhaust gas. 

Disk or cascade evaporators are used in the pulp and paper industry to recover heat and entrained chemicals from boiler stack gases and to effect a final concentration of the black liquor before it is... 

Evaporator, condensate stripper, and black liquor oxidation systems. 

Kraft pulping is a common process in the paper industry. Figure 8.4 shows a simplifled flowsheet of the process. In this process, wood chips are reacted (cooked) with white liquor in a digester. White liquor (which contains primarily NaOH, NaiS, Na2C03 and water) is employed to dissolve lignin from the wood chips. The cooked pulp and liquor are passed to a blow tank where the pulp is separated from the spent liquor weak black liquor which is fed to a recovery system for... 

Three major sources in the kraft process are responsible for the majority of the H2S emissions. These involve the gaseous waste streams leaving the recovery furnace, the evaporator and the air stripper, respectively denoted by R), R2 and R3. Stream data for the gaseous wastes are summarized in Table 8.8. Several candidate MSAs are screened. These include three process MSAs and three external MSAs. The process MSAs are the white, the green and the black liquors (referred to as Si, S2 and S3, respectively). The external MSAs include diethanolamine (DBA), S4. activated carbon, Sj, and 30 wt% hot potassium carbonate solution, S6. Stream data for the MSAs is summarized in Table 8.9. Syndiesize a MOC REAMEN that can accomplish the desulfurization task for the three waste streams. 

Schwarz, n. black blackness, -beere, /. bilberry elder (berry) melastoma. -beize,/. Dyeing) black liquor, iron liquor, scbwarzblau, a. very dark blue. 

Because these variables have a very pronounced effect on the current density required to produce and also maintain passivity, it is necessary to know the exact operating conditions of the electrolyte before designing a system of anodic protection. In the paper and pulp industry a current of 4(KX) A was required for 3 min to passivate the steel surfaces after passivation with thiosulphates etc. in the black liquor the current was reduced to 2 7(X) A for 12 min and then only 600 A was necessary for the remainder of the process . From an economic aspect, it is normal, in the first instance, to consider anodically protecting a cheap metal or alloy, such as mild steel. If this is not satisfactory, the alloying of mild steel with a small percentage of a more passive metal, such as chromium, molybdenum or nickel, may decrease both the critical and passivation current densities to a sufficiently low value. It is fortunate that the effect of these alloying additions can be determined by laboratory experiments before application on an industrial scale is undertaken. 

Figure 2.6 (a) Small WT boiler, for HW/steam (b) large D-type, steam raising, industrial WT boiler (c) radiant WT boiler for utility power and (d) pulp mill recovery boiler, burning black liquor. 

The term waste heat boiler is also widely used to cover heat recovery boilers (HR boilers), which tend to be direct-fired steam generators, albeit employing low-grade by-product fuels such as bagasse, wood bark, com cobs, peanut shells, blast furnace gas, black liquor, and the like. 

Black Liquor Recovery Boilers Many special boiler designs have been developed around the world for the pulp and paper industry, including black liquor recovery boilers. 

Black liquor is 13 to 17% strength, rinsed extract from washed and cooked woodchip pulp, produced in the Kraft pulping process. This... 

Various permutations of the black liquor recovery boiler design are used to combust soda liquors in the soda pulping process and alkaline earth liquors and ammonium liquor (red liquor) in the sulfite pulping process. 

Process contaminants such as black liquor or saponified organic oils (soaps). 

The use of the lignin fraction is much more cumbersome currently the best-known chemical of a real commercial importance is vanillin, which is obtained by oxidation of the black liquor. Another example is a product called spray-dried lignosulfonate (as sodium salt) obtained from the older, acidic sulfite pulping process. It is sold as a commercial product primarily as a concrete additive for enhanced strength. Since the cement industry is one of the big contributors of carbon dioxide emissions (due to the production of calcium oxide from calcium carbonate), the use of this renewable, wood-derived product not only is fossil-carbon neutral in itself but also reduces carbon dioxide emission due to the diminished need for cement in large infrastructures made of concrete. 

Pulping liquors. Pulping liquor, also called black liquor, is a corrosive material used to dissolve wood chips for the manufacturing of paper and other materials. To promote waste minimization and recycling, U.S. EPA excluded pulping liquors from the definition of solid waste if they are reclaimed in a recovery furnace and then reused in the pulping process. If the liquors are recycled in another way, or are accumulated speculatively, they are not excluded. 

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