ASPHALT COMMANDER - Hot-Mix Magazine

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A CARGO OF LIQUID AC The cargo compartments of this ship hold 195,000 barrels of liquid AC—enough to supply the liquid-AC needs of a typical HMA producer for as much as 14 years It is properly named: As the Asphalt Commander, this ship is without question the largest carrier of liquid asphalt cement (liquid AC) in the world. It can carry almost 200,000 barrels of liquid AC from one port to another across the high seas. That is about 8 million gallons of roadbuilding material. And no matter how long the voyage, when it arrives at its destination, it will be able to quickly and efficiently discharge its cargo because the temperature of the liquid AC will be at a workable level—more than 270°F (132°C). This unique vessel has become the premiere carrier for Sargeant Marine, Inc., a Florida-based company that specializes in the sale and transportation of asphalt. With a total of three product tankers currently in operation, Sargeant Marine is unquestionably the world’s leading independent importer/exporter of asphalt. This liquid-AC transport is two football fields long The Asphalt Commander is big by almost any standards. It is 669 ft. (204 m) long. It has an 84 ft. (25.6 m) beam or width. Deeply laden, it draws 36 ft. (11 m) of water. “The usual crew is between 18 and 22 people,” said Capt. Weston L. Stow, operations manager for Sargeant Marine and the person who was in charge of overseeing the refitting of the ship. “That’s not many people for a ship that is more than two football fields long. But the Asphalt Commander is a totally modern ship and the crew requirements are not as great as older ships. The engine room, for example, is completely automated. And the bridge is equipped with what is truly stateof-the-art electronics.” Stow said that there are three other major asphalt ships in the world beside the Asphalt Commander. Two of them are operated by Sargeant Marine. “But the Asphalt Commander is the largest in the world. And it is the only one that sails under the U.S. flag and has a U.S. crew. We’re proud of those facts. We have a manning agreement with the International Organization of Master Mates and Pilots and they provide all crew members. We’re pretty proud of that, too.” The Asphalt Commander is powered by two diesel engines that produce a total of 14,200 hp. It carries enough fuel to provide a range of 24,000 nautical miles, which is equal to once around the On the deck of the Asphalt Commander, you can see a small portion of the header and piping that is used to circulate hot-oil throughout the ship to the various liquid-AC cargo containers. There is a total of more than 22 miles of piping used on the ship, including the coils inside the cargo containers. world. It can steam for 62 days without refueling, although a typical voyage is somewhat shorter. “We could go almost any place in the world with this ship,” said Stow. “But our primary trade will probably be between Venezuela or the Caribbean and the East Coast of the United States. A typical voyage would be between 3,000 and 4,000 nautical miles (5 500 and 7 400 km). You can figure ten days steaming time and eight days loading and discharge. The ship’s second voyage was one for the record books “Our first voyage took us from Curaçao—an island in the Caribbean where a refinery is located—to Charleston, South Carolina. The second trip was from Amuay Bay, Venezuela to Port Everglades, Florida. When the ship reached port, the average cargo temperature was 300° F (159° C) and we were able to discharge the liquid AC at a higher rate than any other asphalt ship had ever done. ”But the real record-setting performance had to do with total cargo. On just its second voyage, the Asphalt Commander lifted the largest asphalt cargo ever lifted by a ship: 195,000 barrels!” According to Stow, they were able to discharge the liquid AC quickly because of the complex and efficient heating system they had installed on the ship during its conversion and refitting early this year. Sargeant Marine worked with Heatec of Chattanooga, Tennessee to design and manufacture hot-oil heaters that would (Continued on Page 8) HOT-MIX MAGAZINE 7 VOLUME 1, NUMBER 5
(Continued from Page 7) keep 8 million gallons of liquid AC at a temperature that was uniformly manageable. This was not Sargeant Marine’s first time to be associated with Heatec. “We’ve done business with Heatec for years,” said Stow. “We have purchased more than 100 liquid- AC shipping containers from Heatec and our association has always been very satisfactory. There’s a lot of mutual trust there. We hold them in very high regard. “But we still shopped this project around. We met with three different suppliers and asked all of them to put packages together and give us bids. And after some more pretty intense meetings, we selected Heatec to do the job.” How Heatec designed the thermal-liquid system: The “job” was more complex than it might appear on the surface. There were 14 different containers built into the cargo hold of the ship. Each had to be outfitted with serpentine heating coils at two levels: high and low. Three hot-oil heaters had to be installed on the deck of the ship. Pumps and control valves had to be strategically placed to provide an even supply of hot oil to the coils. According to Buddy Ledford, the director of engineering for Heatec, his company was probably the only one in the country that could handle the total job. “We are able to do something that is pretty unusual in our industry. We can provide all of the heating coils, as well as the heating source. A lot of companies that make thermalfluid heaters do not make heating coils—and those that make coils do not typically make heaters. We can handle it all: heaters and coils. On this job, it was definitely to the customer’s advantage to have one company that was capable of providing both types of components.” Ledford said that the three Heatec heaters were installed on the main deck of the ship. The large structure that houses the heaters is clearly visible in aerial photos on the aft part of the ship, just behind the stack and the bridge. “Each of the heaters is rated at 15 million Btu,” said Ledford. “Each unit has two circulating pumps, one of which is a standby in case the other fails. All three of the heaters feed into a common header that goes from one end of the ship to the other. There is a minimum bypass valve located in the bow of the ship. Regardless of how many of the 14 cargo compartments are being heated, if they have a heater turned on, there is a flow measurement taken for that heater. That reading goes into a summing controller which controls a minimum bypass valve—and this assures that each heater maintains an absolute minimum flow rate. It’s a pretty complex system—but the heating requirements on this job were also pretty complex.” According to Ledford, the system requires a total of 45,000 gal. (170 000 L) of heating oil. “That includes the oil required in the heater, the headers, and all of the heating coils. Each heater has a minimum flow rate of about 600 gpm (2 300 Lpm). When all three pumps are working, the flow rate is about 2,100 gpm (8 000 Lpm).” A total of 22 miles of serpentine heating coils Ledford said that the heating system uses about 22 miles of the serpentine heating coils in the 14 separate cargo compartments. “We fabricated all of the coils,” said Ledford, “and the shipyard did the actual installation. Imagine: 22 miles of heating coils.” The actual heating process itself is fairly complicated. In a typical cargo compartment or tank, there are two levels of heating coils: one at the bottom of the tank and another about 5 ft. (1.5 m) higher. The low coils do not have a very high heating capacity because In drydock during its conversion and refitting, the Asphalt Commander towered over the workers. In this photo, the ship is far in the background (notice the size of the forklift by the bow) behind Heatec employees Ron Henry (left) and Gary Yearwood (right) who were installing the on-board heaters. they are only intended to replace whatever heat loss there is between the ship’s hull and the water. The higher sets of coils do most of the actual work of heating the liquid AC in the tanks. Once the liquid AC at the bottom of the compartment gets hot enough, it will move up toward the surface. Eventually, the liquid AC will actually roll over and start a circulating motion that keeps the contents of the compartment at an even temperature. The actual work of refitting the ship took a little more than seven months, although the entire project took about a year as far as Sargeant Marine was concerned. “We spent a fair amount of time finding the ship and purchasing it,” said Stow. “It was in the Maritime Administration reserve fleet, excess to the needs of the government. It was a product tanker—originally named the Falcon Champion—and it was a resupply vessel for U.S. Navy tankers. We bought the ship and towed it to Mobile, Alabama for conversion and refitting.” And how did things go after the ship was refitted and renamed the Asphalt Commander? “We had the normal gremlins you’d expect on the first voyage,” said Stow. “But the second voyage was really outstanding! Everyone who has dealt with the Asphalt Commander so far has been very impressed. And that includes everyone in our company. “If you think I’m proud of this ship, you’re right!” ▼▲▼ FOR MORE INFORMATION about Heatec vertical or horizontal storage tanks and heaters— for ocean-going vessels or conventional HMA operations —call and ask to speak with Gail McKeehan: 423-821-5200 (FAX: 423-821-7673) HOT-MIX MAGAZINE 8 VOLUME 1, NUMBER 5
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ASPHALT COMMANDER - Hot-Mix Magazine

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