Explosion pulping

Explosion Pulping. In this process, wood chips about % inch long are fed into a battery of digesters (called gnns), in which the chips are steamed gradually to a pressure of 1100 to 1200 psi and then, after holding at that pressure for about 5 secs, / are released by means of a quick-opening valve into a cyclone. The explosive effect... 

Most of the ammonia produced in chemical factories is used to make fertilizers. The remaining is used in textiles, plastics, explosives, pulp and paper production, food and beverages, household cleaning products, refrigerants, and other products. It i.s also used in smelling salts. 

The principal chemical iadustry based on wood is pulp and paper. In 1995, 114.5 x 10 metric tons of wood were converted iato - 60 x 10 metric tons of fiber products ranging from newsptint to pure cellulose ia the United States (1,76). Pure cellulose is the raw material for a number of products, eg, rayon, cellulose acetate film base, cellulose nitrate explosives, cellophane, celluloid, carboxymethylceUulose, and chemically modified ceUulosic material. 

CeUulose is soluble only in unusual and complex solvent systems. The subject has been reviewed (84—87). Commercially, dissolving pulps, which have lower molecular weights, are used along with strong alkaU and derivatization. CeUulose subjected to high temperature and pressure during the steam explosion process can be dissolved in strong base (88). 

Surface area can accelerate the decomposition of chlorine dioxide up to a point, but sufficient area appears to inhibit catalytic decomposition by adsorption of the intermediates. For example, the presence of fluffed wood pulp or glass wool is reported to stop the explosive decomposition of chlorine dioxide (27). 

Potato meat or Potatopulp Explosives. Expls made by drying raw potato pulp, mixing it with about 80% of its wt of K chlorate, granulating and drying the mixt, and tumbling with graphite to coat the granules... 

In one reported incident sodium sulphide was incorporated into residuary waters from some pulp wood processing, which contained sodium carbonate. This produced an unexplained explosion. 

Semi-chemical pulp contaminated with micro-organisms and incubated at 60°C produces a hydrogen-containing gas. A gas-phase explosion in a pulp storage tower was attributed to static ignition of this gas admixed with air. 

Sallack (1955) was the first to publish a study of dissolver-tank explosions. He was motivated by incidents which occurred in a soda pulp operation with a dissolver tank 4.3 m in diameter and 3.7 m tall. Molten smelt entered the tank at the top and was to be broken up with a jet of recirculating green liquor. Agitation of the bulk liquid was also accomplished by air jets. Operation was normally smooth, but if a boiler upset led to a sharp increase in smelt flow, then the smelt-green liquor breakup operation was inefficient and unbroken slugs of smelt could enter the bulk green liquor in the tank. Explosions could then occur. 

Dynamite is probably the best known explosive. Dynamite is composed of either wood pulp or diatomaceous earth soaked in nitroglycerin and pressed into a stick shape. Nitroglycerin is very unstable—it can explode if it is disturbed—so the wood pulp helps to stabilize the dynamite. 

Three pulp mill workers died after inhalation of fumes for approximately 10-15 minutes from a nitric acid tank explosion (concentrations not available). No significant respiratory complaints were apparent during initial examination. However, 4—6 hours later they became cyanotic with frothy fluid escaping from the nose and mouth. All died in less than 24 hours. Necropsy showed bronchiolar epithelial necrosis, marked capillary engorgement, and slight interstitial edema of alveoli the lungs were five times heavier than normal and released abundant frothy fluid from all lobes. The delayed manifestations of lung injury were consistent... 

Numerous attempts were made to get around the nitric acid problems. At the time, dynamite was well understood, with one variety produced consisting of nitroglycerin absorbed on Kieselguhr (diatomaceous earth). Attempts were made to absorb Hellhoffite on Kieselguhr. Fumes were reduced, but the resulting fill still attacked wrapping paper, wood pulp, metal, and skin. Eventually, the idea of nitric-acid-based explosives was abandoned due to the existence of kinder and gentler alternatives. 

Haloxyline. An Austro-Hungarian explosive invented about 1865. It represents a variety of sulfurless Black Powders such as KN03 75.0, charcoal 8.5, wood pulp 15.0 and potassium ferricyanide 1.5% A similar explosive was patented, in 1866 in England (Ref 1)... 

Hudson Maxim Explosive. An explosive patented in the USA for loading HE shells. It was prepd by blending NC 30-40 with NG 70-60. After the mass hardened it was pulverized and thoroughly mixed with 3-4 parts of wet, finely pulped Guncotton... 

Nitrocellulose Nitric acid. Sulfuric acid. Wood pulp. Sodium hydroxide. Sodium bicarbonate, Carhon disulfide Low explosive. Main component in smokeless powders, lED filler... 

Explosion Unit Operation (See also "Explosive Disintegration"). The explosion technique has been applied successfully for the modification of substances and for separation of components, as well as for size reduction of materials. This method has been used in rubber reclaiming, wood pulping, manufacture of fiber board, pulverization of minerals and coal and finally for the prepn of puffed cereals... 

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