Solids containing corrosive liquids

8 Nitrating acid mixture, spent, 5.1, 8 Nitrating acid, mixture, spent, all concentrations, unstable Solids containing corrosive liquids, n.o.s., 8 

Corrosive materials are those chemicals which, on contact, damage living tissue (skin, eyes, mucous membranes, plant life) and inorganic materials (metals, textiles, ceramics, glass, etc.). They include acids and bases. 

Acids can also exist in non water-based solvents such as ammonia (NH3), where the ammonium ion NH/ is generated by the acid. This concept is generally extended to define acids as those substances that ionize to generate the positive ion of the solvent in which they reside. 

In contrast, bases syn. alkalis are those substances which in aqueous solution form the hydroxyl ion (OH ) that acts powerfully to be oxidized by gaining a 

In nonaqueous solutions, acids accept electrons and bases donate electron pairs for example, ammonia and boron trifluoride react as follows  

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Solids containing corrosive liquids include sand, soil, and debris contaminated with corrosive liquids. 

To avoid injuries of this sort, we should use protective hoods or helmets when breaking joints on lines likely to contain corrosive liquids trapped under pressure, either because the pressure cannot be blown off through a valve or because lines may contain solid deposits. 

Specific types of relief devices are chosen for specific applications, such as for liquids, gases, liquids and gases, solids, and corrosive materials they may be vented to the atmosphere or vented to containment systems (scrubber, flare, condenser, incinerator, and the like). In engineering... 

Hydraulic (Liquid Seal) Flame Arresters Hydraulic (liquid seal) flame arresters are most commonly used in large-pipe-diameter systems where fixed-element flame arresters are either cost-prohibitive or otherwise impractical (e.g., very corrosive gas or where the gas contains solid particles that would quickly plug a conventional arrester element). These arresters contain a liquid, usually water-based, to provide a flame barrier. Figure 23-62 shows one design. Realistic tests are needed to ensure performance, as described in EN 12874 [15]. Note that hydraulic flame arresters may fail at high flow rates, producing a sufficiently high concentration of gas bubbles to allow transmission of flame. This is distinct from the more obvious failure mode caused by failure to maintain adequate liquid level. 

Vacuum filtration has many advantages, not the least being the fact that the feed slurry, often containing abrasive solids in a corrosive liquid, can be delivered by gravity flow or by low pressure pumps which need only to overcome the resistance in the feed pipework. In addition, vacuum filtration equipment does not have to withstand high pressures... 

Sodium borohydride is available as a 12% solution in caustic soda and in solid form either as powder or pellets (3). The predominant form produced is the solution, the DOT shipping classification for which is corrosive liquid. Forms of packaging are 18.9-L pails, 208.2-L drums, and either tank truck or tank car for bulk shipments. 1991 pricing for the solution form was 40.34/kg of borohydride contained. Solid sodium borohydride, a white powder packaged in polyethylene bags in metal containers, was priced at 48.39/kg. 

Mg-Al mixed oxides obtained by thermal decomposition of anionic clays of hydrotalcite structure, present acidic or basic surface properties depending on their chemical composition [1]. These materials contain the metal components in close interaction thereby promoting bifunctional reactions that are catalyzed by Bronsted base-Lewis acid pairs. Among others, hydrotalcite-derived mixed oxides promote aldol condensations [2], alkylations [3] and alcohol eliminations reactions [1]. In particular, we have reported that Mg-Al mixed oxides efficiently catalyze the gas-phase self-condensation of acetone to a,P-unsaturated ketones such as mesityl oxides and isophorone [4]. Unfortunately, in coupling reactions like aldol condensations, basic catalysts are often deactivated either by the presence of byproducts such as water in the gas phase or by coke build up through secondary side reactions. Deactivation has traditionally limited the potential of solid basic catalysts to replace environmentally problematic and corrosive liquid bases. However, few works in the literature deal with the deactivation of solid bases under reaction conditions. Studies relating the concerted and sequential pathways required in the deactivation mechanism with the acid-base properties of the catalyst surface are specially lacking. 

Erosion is the deterioration of a surface by the abrasive action of solid particles in a liquid or gas, gas bubbles in a liquid, liquid droplets in a gas or due to (local) high-flow velocities. This type of attack is often accompanied by corrosion (erosion-corrosion). The most significant effect of a joint action of erosion and corrosion is the constant removal of protective films from a metal s surface. This can also be caused by liquid movement at high velocities, and will be particularly prone to occur if the solution contains solid particles that have an abrasive action. 

Bubble-Tube Systems The commonly used bubble-tube system sharply reduces restrictions on the location of the measuring element. In order to ehminate or reduce variations in pressure drop due to the gas flow rate, a constant differential regulator is commonly employed to maintain a constant gas flow rate. Since the flow of gas through the bubble tube prevents entiy of the process liquid into the measuring system, this technique is particularly usefiil with corrosive or viscous liquids, liquids subjec t to freezing, and hquids containing entrained solids. 

Table 1.29 tabulates most known examples of erosion corrosion problems occuring in aqueous systems. Historically, erosion corrosion first became a problem with the copper alloy (70%Cu 29%Zn l%Sn) condensers of naval shipsErosion corrosion of copper alloys has been an ongoing problem since then. The other major problem areas are (a) power plants where steels are exposed to water or water/steam mixtures in the temperature range 90°-280°C (b) the oil and gas industry where steels are exposed to various liquid, gas, and sometimes solids combinations containing carbon dioxide. 

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