Handling of Chemicals ically changed. Each specification has been made complete in itself. No reference t o a master specification such as ICC-103 or ICC-103-W is now required. The Interstate Commerce Commission and Association of American Railroads paragraphs have been combined wherever possible, the exception being separate Association of American Railroads paragraphs to cover specific materials, references to constructions, and references to figures such as reinforcement diagrams, valves, vents, etc., as included in the Association of American Railroads appendixes. Details on welding have been taken from all specifications and have been written into an Appendix W. This is to become a part
of the Association of American Railroads regulations with reference made to this appendix in each specification, A new Appendix R, Part I, Riveted Tank Car Tanks; Part 11, Fusion Welded Tanks; and Part 111, Aluminum Tanks, is a code for welding repair work which definitely explains how each and every type of welding repair may be made t o these various types of cars. All the retest requirements as now written in t h e specifications have been removed. They are not a part of the construction specifications and will now become a part of t h e Interstate Commerce Commission paragraphs of the regulations covering operation and maintenance.
( Tank Transportation)
TANK VESSELS AND TANK BARGES FRANK G . MOORE Columbia Southern Chemical Corp., Pittsburgh, Pa. A T E R transportation is one of the world's oldest and cheapest methods of moving materials, yet only in the past decade has the chemical industry in the United States made appreciable use of the nation's waterways for the shipment of heavy tonnage chemicals. It is intended here to deal only with inland and coastwise transportation of liquid chemicals. There is comparatively little overseas transport of liquid chemicals in bulk. Statistics on the shipment of liquid chemicals alone are not available, but use of water transportation b y the chemical manufacturers is rapidly increasing. Significant is the following summary of the domestic water-borne movement of chemicals and related products for the years 1949, 1951, and 1953. These figures are believed to be indicative of the trend to water movement of liquid chemicals. 1949 1951 1953 Source.
Net Tons 7,148,311 9,683,359 12,495,344 (est.) Coips of Engineers, U. S. Aimy.
This nation's inland waterways system extends for 28,383 miles. The Great Lakes, with their connerting materrnays, rank :is the world's largest inland water transportation system. The total length of these lakes, including Lake St. Clair, is 1323 miles. It 1s 1160 miles from Duluth on the western edge of Lake Superior to the eastern outlet of Lake Ontario. The Intracoastal Watermay along the Atlantic Coast extends for 1000 miles with a channel 12 feet deep from Trenton, N. J., to Jacksonville, Fla.; it is somewhat shallower from that point to Key West. The Gulf Intracoastal Waterway also extends for 1000 miles from Carrabelle, Fla., to Brownsville, Teu., n i t h a 12-foot rhannel for Its rntire length. I n this country it might be said that the chemical industry is just commencing to make real use of its waterways for the shipment of liquid chemicals in bulk. Regulations of the U. s. Coast Guard, which has supervision of vessels and safety regulations, permit movement of the following liquid chemicals in bulk on the inland and coastwise waterways: b Some of these commodities require special equipment and safeguards. Development of suitable cargo tanks, linings, safety and eduction valves, loading and unloading devices, and other appurtenances have led to the movement in continually larger quantities during the last few years of such products as chlorine, liquefied petroleum gases, caustic soda, anhydrous ammonia, and methane. June 1955
Along with the development of special barges or vessels and tanks that will be capable of carrying the commodity, as well as protecting its quality, has been the necessity for developing terminals and storage facilities at loading and unloading points and handling equipment for transfer of t h e material. BARGE TRANSPORTATION
The Coast Guard is very cooperative in assisting manufacturers, as well as barge and vessel operators, in the development of barges and safety regulations to the fullest extent consistent with safe practices and the protection of the public and other vehicles. This is further evidenced by Coast Guard appointment of a Joint MCA-API Coast Guard Advisory Panel (Manufacturing Chemists' Associatisn-American Petroleum Institute). The American Bureau of Shipping also participates in the approval of
Flammable Liquids acetaldehyde Acetone Butanol (butyl alcohol)" Butyl acetateQ Ethyl alcohol Ethyl chloride Ethylene dichloride Ethyl ether Isopropyl acetate Isopropyl alcohol Methanol (wood alcohol) Vinylidine chloride Corrosives Acid slurry Caustic soda Sulfuric acid (commercial and spentIb Hydrochloric acidb Compressed Gases Vinyl chloride LPG (propane butane)b
Chlorineb Anhydrous ammonia* Methane
Combustibles Acetic acid Acetic anhydride Diethylene glycol Ethylene glycol Ethylene cyanohydrin Furfural Styrene monomer Formaldehyde Class B Poisons Acetone cyanohydrin Phenol
Hazardous Materials Carbon tetrachloride Chloroform Methylene chloride Perchloroethylene Propylene glycol Molten sulfurb Molten asphalt Aqua ammonia Flammable Solids Elemental phosphorusb
a Materials classed as combustible when flash point is above 80' F. and not over 150' F. b Specific requirements have been issued, or are being considered, for vessels to transport these materials.
INDUSTRIAL AND ENGINEERING CHEMISTRY
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barges and vessels by reason of its representation of insurers of cargoes and hulls. Molten Sulfur. Although some movements in experimental barges have taken place, regulations are now being formulated for regular movement of this product by tank barge and some consideration is being given to a limited movement by tank vessel, coastwise. Some of the considerations involve loading and unloading lines because of the temperature of the lading, and dissipation of steam and pressure generated when water enters the tank while it contains hot lading. Methane, Liquefied. This material must be transported a t atmospheric pressure. It is contemplated that power for the towboats on a loaded move of this material might well come from the gas evaporating from the barge tanks. Power for the empty move will come from a small amount of the liquid purposely left in the tanks a t destination. Barges will have separate tanks rather than be of the skin type. Insulation of the tanks will be on the inside with balsa wood which has been "field tested" in a large scale tank containing liquid nitrogen at -320" F. Barges will be of double-hull construction to permit complete control of the barge should the outer hull be pierced. Chlorine. Chlorine is another of the products that required the development of special tanks and appurtenances before they could be transported in quantity in bulk. As a result of the development of the proper tanks and safety devices, the regulation limiting the quantity t o 1 ton per tank was eliminated, and now there is no restriction as to quantity. However, it has been generally conceded that 600 tons t o the barge, loaded in four tanks of 150-ton capacity each, is the maximum desirable quantity of chlorine for movement on the inland waterway, considering safety and other factors. Unlike some other commodities, the chlorine must be weighed prior to loading, as the situation with the barge tanks is the same as with cars-an exact amount is loaded. Lagging of the tanks is not required, b u t devices to prevent manifolding of the tanks are mandatory. There are a number of other important regulatory provisions, some of which are now in process of change. Sulfuric Acid. This product has been moved in tank barges and tank vessels for some years. Probably, as in Europe, it is the chemical that has been moved for the longest period of time. Acid of not less than 52' Baume may be transported without restriction in independent tanks of pressure-vessel type. Acid of 65" Baum6, or greater strength, may be transported in tanks forming an integral part of the vessel. Acid of not less than 60' Baum6, and of greater strength up to but not exceeding 64.75' Baume, may also be shipped in integral tanks, provided that the higher concentration acid has been treated with an inhibitor t h a t renders its corrosive effects on steel no greater than t h a t of 66' Baume commercial sulfuric acid. Spent sulfuric may be shipped in either independent or built-in type tanks, but in either case the tanks must be rubber lined. Only steam-heated coils may be used to liquefy frozen or congealed acid. Hydrochloric Acid. This acid may be transported only in independent tanks of pressure-vessel type. Tanks must be lined with rubber or other approved materials. Improved lining has been developed during the past few years. Piping, valves, and fittings, in contact with the lading, must also be lined, or be made of material that will withstand the corrosive action of the acid. Tanks approved by the Coast Guard for transportation of hydrochloric acid may not be used for the transportation of any other material except upon specific authorization. For the protection of the tanks, extreme care must be exercised in loading and unloading. At times it seems there is more chance of destroying the tank from the outside than from the inside. Caustic Soda. Transportation by water has increased materially in the past few years. Economic conditions, plus improved transportation facilities, have encouraged the water movement. The material is moved in skin-type barges, barges with separate tanks, and tank vessels. The industry has developed im1190
proved lining materials, improved insulation, and improved types of barges and vessels, Where high purity is required, the material must be moved in lined barges or vessels. Linings are of several types, including nickel. The more modern equipment is provided with coils for steaming, and in some cases these coils are nickel. Some barges are equipped with pumps. Some barges have insulated tanks, others do not. consideration must be given t o temperatures when selecting the transportation unit. The material should arrive in condition for easy pumping. Anhydrous Ammonia. Movement of this material, in tank vessels, is just getting started. It may be transported only in independent tanks of the pressure-vessel type. Uninsulated tanks subject to atmospheric temperatures must be designed for pressures of not less than 250 pounds per square inch gage. Insulated tanks must be designed for pressure of not less than 225 pounds per square inch gage. Design pressure of not less than 90 pounds per square inch gage may be used under specific conditions where temperatures of the liquid are maintained below normal atmospheric temperatures by refrigeration and with certain other exceptions. Liquefied Petroleum Gas. Cargo tanks must be independent of the hull and must be designed for a pressure of not less than the vapor pressure of the gas a t 115' F., but for not less than 100 pounds per square inch gage. Except where a refrigerated system is installed to maintain the temperature of the liquid below atmospheric, the tank must be designed for a pressure which is, a t all times, a t least 25 pounds per square inch gage in excess of the vapor pressure (gage) corresponding t o the temperature of the liquid a t which the system is maintained. On LPG barges, cargo tanks having a capacity of not more than 60,000 gallons may form part of the structure where adequate provision is made to prevent damage to tanks in the event of a collision or grounding. All LPG tank vessels must be electrically grounded to shore piping during the entire time cargo hose is attached and must remain so until all spillage is removed. Study and experience have contributed materially to the movement of this material by water. The latest design for sulfuric acid barges is the 175-foot, double skin-type class, with a capacity of 114,000 gallons. The newest thing in hydrochloric acid barges is the 195-foot barge, with four separate rubber-lined tanks, cradled, and with a capacity of 233,600 gallons. I n addition to sizes and types of barges, capacities vary a great d ea1
.
Barrels Acetone Benzene Cyclohexane Ethylene glycol Methanol
7,500 to 9,000
6,500 t o 15,000
9,000 11,000 9,000 t o 11,000
When barges are handled in integrated tows, the quantity transported per trip might reach 74,000 barrels. Barges of 2000-ton capacity and having six separate tanks carry up to 2000 tons of sulfuric acid along the Atlantic Seaboard and the Atlantic Coast inland waterway. Methanol was first transported in liberty tankers in 1948 from Texas to the Atlantic Seaboard. It was the necessity for this type of movement that led to the development of the multipurpose tanker for exclusive transportation of liquid chemicals. Few people realize that a vessel operates regularly, transporting liquefied petrolem gas and ethyl chloride from Texas to the North Atlantic. There are now several tank vessels transporting various liquid chemicals in bulk, coastwise, between the Gulf and the North Atlantic Seaboard. The most modern of these vessels is equipped with specially designed and prepared tanks, pumps, and other appurtenances t o carry 10 or more different chemicals per trip. The carrying capacity of these tankers ranges as high as 16,000 gross tons.
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
Vol. 47, No. 6
Handling of ChemicalsEthylene glycol, methanol, benzene, cyclohexane, toluene, alcohol, and propylene polymer are handled in skin-type barges with capacities from 8000 to 15,000 barrels and load from 1000 to 2200 net tons. The newer barges being built for this service are of the 15,000-barrel capacity. Some barges are equipped with stain-
less steel tanks; others have tanks lined with rubber or other suitable materials; and the latest will be aluminum. Styrene is now moving in appreciable quantities in special barges; here, the temperature must be held down a t timea, rather than kept up.
(Tank Transportation)
TANK TRUCKS W. E. MORGAN Union Carbide and Carbon Corp., New York, N . Y .
T
HE tank truck industry has had the same percentage increase in growth during this postwar period as has the chemcal industry. This coincidence is understandable when one realizes that the chemical industry has been, by far, the most dynamic of industries and the tank truck was the most dynamic development in the transport field during the same period. The tank truck was one of the many factors which assisted the chemical industry to achieve its remarkable growth. The chemical industry, by its expanded use of tank truck services, has helped the tank truck to achieve its current stature. Much has already been published about tank truck transportation of chemicals. I n 1941 there were 4653 for-hire tank trucks with a capacity of 20,159,000 gallons. I n 1951, this figure was up to 15,546 tank vehicles with a standing capacity of 82,888,000 gallons. The average size of tank trucks has increased from 3000 gallons in 1941 to about 4500 gallons today. I n addition to common carrier equipment, there are approximately 7000 tank trailers in private operation. There is no certain method of determining how much of this equipment is in petroleum service and how much in chemical service. However, a conservative estimate is that 10% of this equipment is in chemical service. Most of the carriers hauling chemicals today started out as petroleum haulers and many of them still transport both chemicals and petroleum products. These operators began to eye chemicals transport in the years immediately prior to World War I1 as a result of the extension by the oil companies of their pipelines and expansion of their marine terminals. Probably more important, however, was the experience these operators gained during the war years, when tank cars could not be used for hauls under 200 miles without special permits from the Government. Both industry and carriers were pleasantly surprised a t the compatibility of the tank truck and most chemicals. Accordingly, after the war many chemical companies moved in the direction of expanded tank truck service. One problem presented itself immediately. Before a carrier can operate for hire in interstate commerce, i t must obtain a certificate of operating authority from the Interstate Commerce Commission. Many chemical producers had traffic representatives appear a t hearings all over the country in support of carrier applications for authority to perform this new service. They pointed out to the hearing examiners that there was a public need for this service for many reasons, most important of which were: Elimination of the drum, its cost, and the cost of handling it. This factor is the most obvious; the economies realized in eliminating the container were the basis for the establishment of a bulk pricing system in tank cars which was later extended to include tank trucks. The tank truck will arrive a t destination much sooner than a tank car. A truck will deliver the same day within 100 miles, the next day within 250 miles, the second morning up to 500 miles, and the third morning within 750 miles. The rails may take a t least 3 days for the shortest haul and up to 10 days for 750 miles. June 1955
The shipper does not have t o rent tank trucks as he does tank cars. The tank truck rate includes the use of the tank truck. Because of its speed, a single tank truck can replace several tank cars, particularly on short-haul traffic. There are cases reported where two or three tank trucks replaced fleets of 10 to 20 cars on a short-haul, 24-hour operation. Tank trucks range in size from 3000 to 6000 gallons. I n certain states, combinations of a straight tank truck and a trailer, or trailer and trailer, permit shipment of quantities as high as 7500 gallons. A number of tank trucks are compartmented, some having as many as five or six compartments, permitting the transportation of several diffeient commodities at once, or deliveries to more than one customer or to more than one destination. The customer does not have to be located on a rail siding and does not need as much storage area. All chemicals users can benefit from bulk deliveries from plants and bulk stations located in the industrialized sections of the country without the capital expenditures required for large bulk storage installations. Inventory Control. With same-day or overnight delivery in smaller quantities, the customer can exercise greater inventory control. Producers too, can work on tighter schedules without as much concern over the storage of production pending receipt of orders. Both the buyer and seller have a closer control of the product flow. The tank truck becomes part of the production line. On most of the carrier applications for tank truck authority that Union Carbide supported, the Interstate Commerce Commission found that these factors justified granting the authority. As a result, today, the company can supply virtually every part of the country by tank truck from one or more of its plants or bulk stations. PROBLEMS OF TANK TRUCK TRANSPORTATION
As the tank truck was used more, all was not sweetness and light. First, a large part of plant facilities had been built long before anyone gave much thought to the idea of a tank truck. Proper tank truck-loading facilities had to be set up, to avoid payment of heavy demurrage. The tank truck operators allow only 1 to 1.5 hours for loading and the same time for unloading. If more time is required, the detention charge ranges from $4 to $6 per hour. Secondly, some tank truck operators had pretty weird ideas as to what was meant by a clean tank. Most of these operators were relying on their petroleum experience. This did not work out very well in handling chemicals, with their varying characteristics coupled with the absolute requirement for delivery of a pure product, free from contamination. The carriers have since spent much time and money in training their personnel in the proper handling of chemicals. With several of the larger companies, the chemicals operation was divorced entirely from the petroleum. The carriers hired men with chemical training. They met with plant personnel and worked out procedures which assured the safety of personnel and quality of product. Supervisory employees became real specialists in the transportation of chemicals.
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