Articles & News
Articles & News
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- by Emily Gudermuth
In December Port City Daily in Wilmington, North Carolina, featured Enviva’s latest portside project, highlighting the eco-friendly approach to energy production that […]
In December Port City Daily in Wilmington, North Carolina, featured Enviva’s latest portside project, highlighting the eco-friendly approach to energy production that wood pellets provide.
The article details Enviva’s Port of Wilmington project, which wrapped up in 2016 after Dome Technology provided two 45,000-metric-ton domes designed to withstand hurricane and earthquake forces. The domes store pellets delivered by truck or train until ready to be shipped via barge.
In the past five years Dome Technology has built four total domes for Enviva. The first two were constructed between 2011 and 2012 at the Port of Chesapeake in Virginia. The domes, which are nearly identical to those at the Port of Wilmington, stand 157 feet high and 176 feet in diameter and feature systems that continuously monitor and control interior temps.
Domes provides ideal conditions for storing wood pellets. The airform surrounding the entire dome prevents water and moisture access. The dome’s insulated nature reduces heating and cooling of the walls and air inside, preventing condensation from forming on the interior. Layers of concrete, rebar, and insulation provide humidity control and moderate externally generated temperature fluctuations. For storage on a port, domes can be engineered with innovative foundation systems that provide ample support on soil near the water.
To read the full Port City Daily text, click here. For information about how domes effectively store wood pellets, click here.
Photo via Port City Daily.
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On Dec. 22 NBC affiliate WECT in North Carolina highlighted Enviva’s preparation to ship its first barge of wood pellets to the […]
On Dec. 22 NBC affiliate WECT in North Carolina highlighted Enviva’s preparation to ship its first barge of wood pellets to the United Kingdom. Click here for the video.
The wood pellets are stored in two domes built by Dome Technology, with each dome storing up to 45,000 metric tons. According to the video, Enviva could ship as many as 20 runs to Europe in 2017.
The domes can withstand winds up to 300 mph and will store pellets produced at Enviva’s Sampson plant, as well as additional regional wood-pellet production facilities that may be built in the future.
Domes are an ideal bulk-storage option for wood pellets as they store a large volume in a smaller footprint, stacking product deeper than a silo of similar dimensions. For storage on a port, domes can be engineered with innovative foundation systems that provide ample support on soil near the water. Domes are also less likely to experience fires because the interior is truss and support free—the fewer the horizontal surfaces, the fewer places for dust accumulation.
For more information on domes and wood-pellet storage, click here.
Image via WECT.
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Editor’s note: This is an excerpt from a feature published in the November 2016 issue of Dry Cargo International. Storing […]
Editor’s note: This is an excerpt from a feature published in the November 2016 issue of Dry Cargo International.
Storing cement is a heavy matter. High density often requires soil improvements or deep foundations. Moisture damages product quality. Poor handling can result in compromised or unusable cement.
These were some of the concerns facing by St. Marys Cement as they planned for a storage facility in Chicago. A dome, with its versatile reclaim options, was selected for an existing St. Marys transload facility on Lake Michigan that received via ship cement made at the company’s Charlevoix, Michigan, plant and elsewhere, temporarily stored it, then loaded it onto trucks for transport.
“(St. Marys) was looking for additional storage capacity and an economical solution; domes provide both,” plant manager Randy Pryor said. The project wrapped in January 2016.
Until the new dome was built, the Chicago facility did not have the capacity to store the volume shipped from the Charlevoix plant. The completed dome is allowing St. Marys “to get the dome filled before the lakes freeze over and (they) can’t get ships down there,” Dome Technology operations manager Brent Hardy said.
Total reclaim was another must, and rather than opting for a traditional cement-handling system, St. Marys chose a hybrid system of airslides paired with a Laidig reclaim screw.
“The fluidized screw … will provide a more mechanically reliable solution, as compared to other mechanical reclaim systems. It will also provide for more complete reclaim of stored product compared to other mechanical systems or aerated floors,” Pryor said.
Employees are safer and operations more efficient with the reclaim system St. Marys selected. “The Laidig system greatly reduces (the safety) risk by providing inherent redundancy associated with having two different reclaim methods. Hard-pack areas or dead zones that are not reclaimed by the air-gravity conveyors are broken down and reclaimed by the screw conveyor without putting personnel at risk,” Pryor said.
Increased storage means St. Marys can deliver cement — and cost savings — to customers year round.
“St. Marys has in the past run low on product in the Chicago area and relied on trucks to get them the material needed to supply their customers through the winter months when the lake was frozen over and they were unable to bring it by ship,” Hardy said. “The additional 50,000 tons of storage provided by the dome at Chicago will help them serve their customer base better through the winter and to help pass on the savings to their customers (since) the cost of bulk transport by ship is fractional to the cost of hauling it over the road by trucks.”
For the full text, including five reasons domes are ideal for cement storage, click here to view the November 2016 issue.
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Editor’s note: This is an excerpt from a feature that ran in the December 2016 issue of World Coal. To meet […]
Editor’s note: This is an excerpt from a feature that ran in the December 2016 issue of World Coal.
To meet the electricity needs of a burgeoning middle class, China Coal needed serious storage times six.
The company contracted Dome Technology of Idaho Falls, Idaho, USA, to provide bulk-storage for two sites, one in Hulusu and the other in Menkeqing. Each site features three coal domes capable of storing 60,000 metric tons apiece.
At both sites, Dome One houses coal arriving fresh from the mine. As coal exits the dome, it passes through a cleaning and washing process before being milled to achieve the right-sized pieces. From there, coal is dumped via conveyor into Domes Two and Three, where it later exits the structures in one of three tunnels on its way to trains waiting outside.
Domes make more storage possible within a smaller footprint, so China Coal can store more in a smaller footprint than warehouses or flat storage would allow. Product can also be stacked deeper within a dome, meaning that for many companies, one dome might accommodate the same amount of material as multiple flat-storage structures.
The storage space available on a relatively small piece of land was one of the most significant dome advantages, explained Zhao Jiapeng of China Coal. But storage wasn’t the only consideration. If the project were to be a success, China Coal also needed speed in reclaim and safety solutions.
Efficient reclaim: 100 percent live-reclaim full-hopper floor
If China Coal’s domes were going to deliver on speed and necessary throughput, selecting the right reclaim system was a must. In each dome, the reclaim workhorse is a 100 percent live-reclaim full-hopper system, similar to a series of funnels situated side by side through which coal flows under its own weight rather than being moved by loader or other mechanical equipment. The full-hopper floor system is controlled with gates on the hoppers so site superintendents can meter flow to the belts. The floor’s design allows each dome to be emptied every three days, meeting the company’s handling needs.
“China Coal was looking for high throughput without any mechanical cleanup, and that hopper floor system allowed them to do that,” said Dome Technology CEO Bradley Bateman, who acted as project engineer for the six domes.
This innovative model is ideal for lower-volatility coal, like that stored by China Coal, because the product’s shelf life is long enough to be safely stored in this environment. “It’s pretty new—the industry hasn’t done a lot of this because of the scale,” Bateman said.
The full-hopper system provides first-in, first out reclaim desirable with types of coal prone to spontaneous combustion. Since self-combustion is mainly dependent on time, the longer coal sits, the more likely it will combust. According to engineer for Dome Technology Adam Aagard, storage structures with just one central tunnel will reclaim a portion of the bottom cone of product, but everything off to the side comprises a static pile. Until that portion of the pile is drawn down and moved via loader, aging in pile is a real concern.
A system providing full cleanout without mechanical parts is an ideal option. “There are other systems, but not too many, that companies can achieve 100 percent reclaim with, but they cost money to run; they break down. Gravity doesn’t break down; gravity doesn’t cost money to run,” Aagard said.
Now in their second year of operation, the six China Coal domes are making it possible for large amounts of coal to be mined and properly stored in north China’s Inner Mongolia province. With 100 percent live reclaim, fire prevention, and environmental protection covered, domes meet and exceed the needs of coal companies around the world.
For the full text, including information about safety solutions and environmental protection, visit this site and click on “Preview PDF.”
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Food Business News recently published an article about United Sugars Corporation’s new dome, built by Dome Technology, in Montgomery, Illinois. […]
Food Business News recently published an article about United Sugars Corporation’s new dome, built by Dome Technology, in Montgomery, Illinois. Click here for the full text.
The dome stands 134 feet tall and 183.7 feet in diameter and can store 60,000 metric tons of sugar. American Crystal Sugar Company owns the facility, and United Sugars Corporation will oversee operations. Filling of the dome is scheduled for December 2017.
The dome is equipped with mechanical systems providing a fill rate of 200 metric tons per hour and a reclaim rate of 150 metric tons per hour.
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Storing fertilizer is one thing, but handling it properly is quite another. The first step for handling success is to […]
Storing fertilizer is one thing, but handling it properly is quite another.
The first step for handling success is to consider the big picture—hourly and annual tonnage requirements, throughput needs, and more. The standard handling mechanism outside the storage facility is straightforward—usually conveyance via belt and reclaim via front-end loader—so major material-handling decisions must be made for systems within the structure. Here are five considerations when planning a project:
1. Select the right storage facility.
Because fertilizer is hygroscopic, some companies opt for wooden warehouses since wood is naturally inert; however, a concrete dome designed to hold the same amount of material is significantly less expensive, said engineer for Dome Technology Adam Aagard.
Two major perks for storing fertilizer in a dome are economy and longevity. Much of the cost savings in a dome comes from humidity control and finish options that protect the product. As far as longevity, a dome is built to last decades, and with the necessary finishes, the structure can withstand corrosion.
Many companies store bulk amounts within separate domes, then mix them in smaller batching facilities outside the storage areas. Domes offer the most economical value for large dry-bulk storage, so other types of small structures are commonly used for storing smaller quantities or when mixing fertilizer within the structure.
2. Understand the product.
Regardless of the product being stored and handled, an understanding of all physical and chemical properties is a must, said Charles Formisani, vice president of sales for A.J. Sackett and Sons Company, an industry leader in fertilizer-handling systems. With a basic understanding engineers can begin delivering on other requests—upstream and downstream processes, hourly and annual tonnage requirements, site-specific safety requirements, accommodating preferred vendors for mechanical components, and more, he said.
Whether or not the stored product has been prilled will affect the handling-system design. Prilled product is more susceptible to degradation, so gentle handling is a must—but “the more gently you handle it, the more it costs,” Aagard said. Unformed or unprilled product doesn’t require gentle handling, so a low-tech, less expensive option is one way to cut costs. Both prilled and unprilled fertilizers are corrosive, so stainless or non-corrosive finishes are the standard.
3. Control humidity.
Water wreaks havoc on fertilizer; since most fertilizers are hygroscopic, they attract moisture that dissolves the product and corrodes it too, producing weak acids that break down steel and damage concrete. Dome customers are advised to allot a portion of the budget to corrosive-resistant rebar and/or additional concrete over rebar.
To protect product from humidity, a dehumidifier is highly recommended. Humidity monitors can also be installed, allowing site managers to survey and adjust interior conditions.
4. Deal with fines.
Smaller particles ought to be evenly dispersed in the storage; if not, fines will concentrate in the middle of the pile and glue together more firmly than solid, larger particles—and that can cause serious reclaim problems. Selecting the right distribution spout can ensure that solid, larger particles are more evenly mixed with fines. A common solution is an umbrella spout that dumps fertilizer onto an umbrella-like structure and fans out the product. Not only is this option effective, but it’s fairly inexpensive, Aagard said.
5. Identify maximum stacking depth.
When stacked too tall, some fertilizers will crystal-bridge together, making reclaim difficult. A point-level monitor tracks the stack so site managers know how much they’re storing and can adjust throughput as needed.
This is an excerpt from a feature published in the September 2016 issue of World Fertilizer.
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Today’s bulk-storage solutions are relying more and more on fully automated systems. Here are some common automated systems now engineered into […]
Today’s bulk-storage solutions are relying more and more on fully automated systems. Here are some common automated systems now engineered into domes:
• Systems monitoring conveyors are especially important as poor belt-idler maintenance is one of the greatest causes of fire within storage facilities. If idlers fail to spin properly and the belt continues moving anyway, the system can take fire and the conveyor can carry the flames right into the storage vessel. Sensors are also installed to analyze bearing alignment. In both instances, the systems shut down when a problem is detected, and site operators are notified.
• Plug-chute sensors detect when a chute gets plugged, preventing large spills. Damage belt detectors detect damage that could contribute to the conveyor failing while the belt is loaded with product.
• Temperature and humidity control loops are essential; a cable array hung from the roof of the dome monitors both. Using this information, a controller or processor starts and stops fans or dehumidifying units to keep levels within specified amounts.
• Multiple-gas detection systems monitor off-gasses. In the case of wood pellets, for example, this system tells customers how aged pellets are by identifying where they are in the process of decomposing, and watching those levels provides clues that fire could soon be possible. For instance, a Firefly gas-detection system detects off-gases as well as those produced by smoldering.
• Point-level monitors identify the height of the product in the dome, and more specialized 3D monitors chart the surface of the pile and its shape—information crucial for inventory management and knowing how much product is being stored (and is aging, if applicable).
• Moisture meters can be installed on the inbound feed to detect if the product is off spec, failing to meet requirements for heat or moisture. Customers are alerted if bringing in something too hot, too dry, or too wet and can reject the product.
• Conveyor components can be mechanized, allowing a facility manager to easily control product-direction flow. For instance, if product ought to be stored in a specific dome, all diverters move so product goes where intended with the push of a button. Similarly, systems can control whether product moves from dome to dome or out to ship, train, or truck. Operators do not have to check if the diverter gate is in the correct position because the PLC receives feedback from the gate showing its position.
• Convenient safety devices make it easier to halt operation as needed. Most mechanical systems are engineered with emergency stop buttons in key places throughout the facility.
Along the conveyors, a pull-cord system allows workers monitoring the material handling to stop operations even when a stop button is out of reach.
The two most important features of operational safety—housekeeping and maintenance—can’t be engineered into the system and must become part of routine operations. But when automated systems and routine maintenance work in tandem, a site runs more efficiently and safely day in and day out.
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For years the bulk-storage industry was dominated by options requiring manpower and near-constant attention, but today’s trend leans more and […]
For years the bulk-storage industry was dominated by options requiring manpower and near-constant attention, but today’s trend leans more and more towards fully automated systems. To get the best systems, a turnkey solution has become more common, where companies select one provider for all the storage and handling systems necessary—not to mention operation made possible by pushing a few buttons.
“Lately there’s really been a shift to a complete automated system,” said Casey Bame, engineer and automation designer for Dome Technology projects. “In the long run (companies) can save a whole lot of manpower from not having someone out there turning things on and off.”
One of the greatest benefits of automation is that potential problems can be detected early enough that the site manager can be alerted before the system has to shut down. That way, material handling can continue without interruption as issues are resolved.
In pursuit of a well-automated facility, companies ought to consider selecting one provider for construction, where the mechanical, structural, electrical, and automation engineering are all done by a single company; this ensures better coordination since coworkers manage their portions of the project together, crafting systems that run smoothly with one another, Bame said.
Dome Technology engineers can design a variety of control systems with the most common being systems that run on a programmable logic controller, a complex computer-and-sensor system collecting data, analyzing it, and dictating that operations function properly and run in the correct sequence—Conveyor A before Conveyor B, for instance. Utilizing sensors on the conveying system, the PLC can inform the operator if the belt is getting out of alignment, not running properly, or if the bearings are getting too hot; advance notice can prevent costly repairs and unnecessary downtime.
With the importance placed on safety, the PLC along with pull cords and push buttons can be valuable tools to keep people safe and machinery undamaged. The use of variable frequency drives to dictate the speed of the conveyors can help a plant run more efficiently and prevent expenses such as the high in-rush current of large motors.
The design and engineering of the automation is completed during the same time as the mechanical system, and they work together to provide a proper system that meets the customer’s needs. Upon installation, an on-site operator—someone from the customer’s company—is trained on how the systems work.
This kind of engineering eliminates much of the potential for human error and relieves the burden on site operators.
Check back next week for a list of automated systems now engineered into domes.
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Safe and efficient coal handling translates into cost savings and a boosted bottom line for coal companies. Selecting the ideal […]
Safe and efficient coal handling translates into cost savings and a boosted bottom line for coal companies. Selecting the ideal material-handling system is essential, and Dome Technology is an industry leader not only in storage facilities but also in the optimal handling systems inside and outside the dome.
Handling and reclaim
Selecting the right reclaim and handling systems — not just those moving product within the structure, but loading and reclaim systems too — is key for future financial success. Working with a single team that engineers the storage structure and its material-handling systems results in a seamless, efficient facility.
Coal throughput rate is of utmost importance as it determines the material-handling systems. With both low- and high-volatility coal, “the goal is first-in, first-out. That helps to minimize residence time” and the likelihood of fire and explosion, engineer for Dome Technology Adam Aagard said.
The stacker reclaimer is common for more highly combustible varieties of coal handled by a mechanized system, and the greatest benefit is increased control over where the pile is built and what portion is reclaimed. For instance, if a hot spot is detected, site managers can remove product from a specific area in a hurry.
Another option for some types of coal is a full hopper system. Similar to funnels situated side by side as the “floor” of the facility, this model allows coal to flow through the structure under its own weight rather than by loader. Dome Technology has installed this type of 100 percent live reclaim in projects of various sizes, with the largest being in domes that hold 60,000 metric tons.
Indonesian, PRB or similar types of coal require particular attention to detail when designing and operating to ensure safe storage and handling.
Conveying systems
Conveyors require their own monitoring to ensure proper function, and Dome Technology commonly installs and recommends these systems for coal handling:
>> Infrared cameras check coal temperatures while on the belt to prevent off-spec product from entering the dome.
>> Linear heat cables monitor for fire on the belt and examine bearings for sparks, often detecting a fire traveling along the belt before it reaches the thermal scanner. The system then stops conveyance and alerts facility management of the fire. Workers can either extinguish the fire, or an existing fire-suppression system puts out the flames.
>> Specialized admixtures can be added to the water to aid in quicker cooling and suppression. One option is Hazard Control Technologies’ F-500 Encapsulator Agent that, when proportioned into the water system, extinguishes flames and cools the system faster than water alone could, absorbing as much as 10 times more heat energy than plain water, according to the company.
Dust collecting
Dust collection too requires its own set of precautionary measures, and Dome Technology recommends a wet scrubber that pulls dust through a water system, “and that’s what pulls out the dust rather than a bag, so now the dust is wet and not nearly as combustible,” Aagard said. The system pulls the dust through a duct until it can be removed from the facility or destroyed.
Regardless of the type of dust collection, an automatic system can convey dust away, whether pneumatically or on a belt, to a combustor. Another option is for dust to be collected in a bin or super sack to be hauled away.
In addition to these design measures, proper housekeeping is critical for safe operations at a coal facility. For an in-depth discussion about fire prevention, click here.
This is an excerpt from a Dome Technology article that ran in the June 2016 issue of Dry Cargo International.
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Providing customers with engineering and construction service together brings value to the project by delivering solution-oriented problem solving. But four […]
Providing customers with engineering and construction service together brings value to the project by delivering solution-oriented problem solving. But four additional means of analysis and engineering that work together now and into the future are listed below:
Geotechnical analysis
Making the selected site work best for a customer is one of the first considerations for a project’s success. Since every location around the world is unique, every dome needs to be supported in a unique way. And since each dome holds different materials in different quantities, the product and soil profile determine the necessary support beneath it. Geotechnical analysis considers the soil stratification and site history, and the findings identify risk tolerance and settlement tolerance. The most complementary foundation is then selected for the project.
Engineering for material-handling systems
The way a dome system works depends on the product. Whether companies need bucket elevators, traditional conveyors, drag-chain conveyors or pipes that transport product pneumatically, Dome Technology engineers use their material-handling know-how to customize a system. The design-build team creates systems working within the dome and those working outside to move stored products into and out of the structure and all the way to the train, boat or truck.
How companies receive product from origin, how they transport it from place to place and how equipment ought to be monitored determine the dome mechanics. Attention to the details of stored products — wood pellets requiring a certain moisture content or coal kept cool enough to safely store, for example — informs the process of selecting equipment for material handling.
Structural engineering
The dome’s double curvature and structural engineering render it stronger than traditional structures, even when spanning as much as 330 feet. The dome consists of an outer PVC membrane, polyurethane insulation and layers of steel-reinforced concrete. The construction process produces a super-strong structure, one that can support a head-house transfer tower that a comparative structure just couldn’t tolerate without tremendous extra support and cost. The self-supporting dome needs no interior beams or columns.
Electrical engineering
Dome Technology’s electrical engineers can design any type of electrical system — monitoring equipment, reclaim equipment, lighting for the site, lighting for the walkways, conveyors, dust-handing systems and more. Then the team identifies the size of electrical service and creates the logic to start and operate the facility.
More and more often, engineers design systems that run on a programmable logic control, a complex computer-and-sensor system that ensures operations run in the correct sequence — Conveyor A before Conveyor B, for instance — and detects when things go awry. If there’s an error, the system shuts down automatically until the operator resolves the problem and restarts the system.
This level of engineering eliminates much of the potential for human error and relieves the burden on site operators and customers alike.
The above is an excerpt of a Dome Technology article that ran in the June 2016 issue of Dry Cargo International.