Corrosion transportation

Carbohydrazide itself is of very low volatility, but it decomposes at relatively low temperatures to produce volatile carbon dioxide and ammonia. In theory, the combined corrosive effects of these two materials should be negated in the condensate system, but in practice, this is not always so and both steel and copper corrosion transport problems may develop, primarily as the result of corrosion-enhancement reactions resulting from oxygen in-leakage. It is presumed, therefore, that (similar to hydrazine) some deliberate after-desuperheating line addition of CHZ is necessary if post-boiler section corrosion is to be avoided. 

Transport of 70% ether sulphates is often carried out in drums. The drums should have removable polyethylene liners to ensure product quality. Care must also be exercised not to overheat the drums, because of potential damage to the polyethylene drum liners. Temperatures in excess of 50°C can cause the ethoxysulphate to hydrolyse and become corrosive. Transport in tankers can be considered but it is preferable to deaerate the product before tanker loading. 

The amount of processing required in the field depends upon the composition of the gas and the temperature and pressure to which the gas will be exposed during transportation. The process engineer is trying to avoid liquid drop-out during transportation, since this may cause slugging, corrosion and possibly hydrate formation (refer to Section 10.1.3). For dry gases (refer to Section 5.2.2) the produced fluids are... 

The end product specification of a process may be defined by a customer (e.g. gas quality), by transport requirements (e.g. pipeline corrosion protection), or by storage considerations (e.g. pour point). Product specifications normally do not change, and one may be expected to deliver within narrow tolerances, though specification can be subject to negotiation with the customer, for example In gas contracts. 

Although many problems still remain to be overcome to make the process practical (not the least of which is the question of the corrosive nature of aqueous HBr and the minimization of formation of any higher brominated methanes), the selective conversion of methane to methyl alcohol without going through syn-gas has promise. Furthermore, the process could be operated in relatively low-capital-demand-ing plants (in contrast to syn-gas production) and in practically any location, making transportation of natural gas from less accessible locations in the form of convenient liquid methyl alcohol possible. 

Caustic soda is classified as a corrosive material by the DOT and DOT regulations and specifications must be followed for handling, labeling, and transportation in containers. Warning labels are recommended for containers of caustic soda solutions and anhydrous caustic soda by the MCA (79). The DOT identification number is UN1824 for 50 or 73% Hquid, and UN1823 for anhydrous caustic. 

Specifications, Shipping, and Analysis. Hydrogen fluoride is shipped in bulk in tank cars (specification 112S400W) and tank tmcks (specification MC312). A small volume of overseas business is shipped in ISO tanks. Bulk shipments are made of anhydrous HF as well as 70% aqueous solutions. A small amount of aqueous solution may be shipped as 50%. Cars and tmcks used for anhydrous HF transport are of carbon steel constmction. It is possible to ship 70% aqueous in steel from a corrosion standpoint however, mbber lining is commonly used to eliminate iron pickup, which is detrimental to product quaUty in a number of appHcations. Hydrogen fluoride of less than 60% strength must always be shipped in lined containers. 

The DOT ha2ard classification of formic acid is "corrosive material." A DOT white label is mandatory for transportation. The EC classification is "corrosive."... 

Shipment of hydrazine solutions is regulated in the United States by the Department of Transportation (DOT) which classifies all aqueous solutions between 64.4 and 37% N2H4 as "Corrosive" materials with a subsidiary risk of "Poison". Hydrazine has been identified by both the Environmental Protection Agency and the DOT as a hazardous material and has been assigned a reportable quantity (RQ) of 0.450 kg (1 lb) if spilled. Dmms for the shipment of these solutions must bear both the DOT specification "Corrosive" and "Poison" labels in association with the markings "RQ Hydrazine Aqueous Solution UN 2030." Aqueous solutions of 37% concentration or less are a hazard Class 6.1, UN 3293, Packing Group III and require "Keep Away From Food" placards and labels. 

The Department of Transportation classifies HCl as a corrosive material and requires that it be transported in DOT-approved deHvery vessels. Tank cars must conform to 103B, 103B-W, or DOT 111A60W5 specifications. Tank trailers must conform to DOT MC-310, MC-311, MC-312, or DOT-412 specifications with display of a corrosive placard on both sides, front, and rear of the tank. The United Nations identification number for muriatic acid is UN1789, which must appear on aH shipping papers and placards. 

Concentrations over 8 wt % are classified as corrosive Hquids by the Department of Transportation (DOT). The Bureau of Explosives regulation (132) classifies all solutions containing 20 wt % and greater as oxidizers and corrosives. The product containers must have identifying labels (dmms) or placards (tank cars, tank trailers) indicating that the contents are an oxidizer and corrosive material, UN 2014 or UN 2015. Bills of lading must also be so identified. Tank cars and tank trailers are constmcted from high purity aluminum or 300 series stainless steel. 

The possible remedial and preventive actions are hot soaks and drains during cooldown to help remove soluble deposited material, chemical cleaning to remove corrosion products and reduce the pressure drop (see Metal surface treatments), and reduced corrosion product transport into OTSG using amines other than ammonia in feedwater (14). 

The CORA II Model of PWR Corrosion-Product Transport," Report NP-4246, Electric Power Research Institute, Palo Alto, Calif., 1985. 

Finish removers are appHed by bmshing, spraying, troweling, flowing, or soaking. Removal is by water rinse, wipe and let dry, or solvent rinse. Removers may be neutral, basic, or acidic. The viscosity can vary from water thin, to a thick spray-on, to a paste trowel-on remover. The hazard classification, such as flammable or corrosive, is assigned by the U.S. Department of Transportation (DOT) for the hazardous materials contained in the remover. 

The triple salt is classified by the UN not as an oxidizer but as a corrosive, and thus must be transported under the UN No. 1759 for corrosive soHds NOS. It should be kept away from combustible material. 

Liquids. Liquids usually are moved through pipelines (qv) by pumps. Special alloys, plastic pipe and liners, glass, and ceramics are widely employed in the chemical industry for transport of corrosive hquids. Care is required in making the connections, to prevent exposure of unprotected metal such as flanges and bolts to the corrosive material inside the piping. 

Mild steel can be used for transport and storage if product discoloration is not a problem, such as in gas conditioning appHcations. Contact with copper, brass, and other copper alloys may cause corrosion of the metal. 

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