Articles & News
Articles & News
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Editorโs note: This is an excerpt from a feature that ran in World Coalโs March 2017 issue. To meet the electricity […]
Editorโs note: This is an excerpt from a feature that ran in World Coalโs March 2017 issue.
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 wasnโt 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 Coalโs 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 floorโs design allows each dome to be emptied every three days, meeting the companyโs handling needs.
โChina Coal was looking for high throughput without any mechanical cleanup, and that hopper floor system allowed them to do that,โ 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 productโs shelf life is long enough to be safely stored in this environment. โItโs pretty newโthe industry hasnโt done a lot of this because of the scale,โ 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. โThere 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 doesnโt break down; gravity doesnโt cost money to run,โ 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 Chinaโs 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 more information about safety solutions and environmental protection, see the full article by visiting this site and clicking on March 2017’s โPreview PDF.โ
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On March 7 northeast Mississippiโs Daily Journal published an article highlighting two Dome Technology domes being built as safe shelters […]
On March 7 northeast Mississippiโs Daily Journal published an article highlighting two Dome Technology domes being built as safe shelters near high schools in Pontotoc, Mississippi.
Both domes will stand 116 feet in diameter with a 23-foot-high dome atop a 14-foot stem wall. One safe shelter will service North Pontotoc High School, and the second will be located on South Pontotocโs campus; the structures can shelter approximately 1,100 people apiece. Completion is expected in December 2017, and the shelters will be used as multi-purpose classrooms when not needed during storms.
Pontotoc County School District will pay 10 percent of the cost for each structure, and FEMA funds will cover the remaining 90 percent. According to the Daily Journal article, the school district will tack on an additional 10 percent in optional features.
Dome Technology builds freestanding safe shelters like these for communities all over the U.S., especially in areas prone to tornadoes and hurricanes. Often a portion of the construction cost is funded by FEMA grant dollars; through the Hazard Mitigation Grant Program, projects in accordance with ICC-500 codes can qualify for government funding covering a portion of the projectโs exterior or shell.
For a safe shelter to qualify for federal funds, certain qualities must be present. The structure must be able to withstand windborne debris, providing a protective layer that prevents penetration from outside objects. The shelter must tolerate specified sustained wind speeds; hurricane shelters must withstand up to 200 mph winds, and tornado shelters must withstand up to 250 mph winds. Sufficient open space must also be available inside for sheltering as many people as possible.
Dome Technology concrete domes can meet these criteria, and since 2012, the company has completed 20 safe-shelter projects.
Domes are especially suited for weather resistance thanks to geometry. Their robust nature โcomes from the fact that the dome has a monolithic construction and also the shape of the domeโit helps distribute applied forces across the entire surface of the structure,โ engineer for Dome Technology Mike Gibbs said.
For more information, visit our article on storm shelters.
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Editor’s note: This article ran in its entirety in the Feb. 2017 issue of World Cement. By Rebecca Long Pyper […]
Editor’s note: This article ran in its entirety in the Feb. 2017 issue of World Cement.
By Rebecca Long Pyper for Dome Technology
The go-to option for moving cement is a pneumatic systemโand for good reasons. Fluidized floors boast complete reclaim of stored material, low system maintenance and elimination of restrictions that would inhibit flow.
โPneumatic systems are pretty much bulletproof,โ said engineer for Dome Technology Adam Aagard. โVendors will do a lot of the basic conveyance design to ensure that the right pump, compressor and blowers are selected,โ and will also help cement companies identify the appropriate size of equipment depending on reclaim needs.
But according to David Bergenstock, FLSmidth sales manager of pneumatic transport systems and products, another important considerations is the type of cement being handled. Cement producers often blend Type I and Type II Portland Cement with supplemental cementitious materials (SCMs) like fly ash, ground blast furnace slag and pozzolans to increase long-term strength or to improve other mechanical or chemical properties. These materials may also improve conveyability and lubricity, while presenting an environmental benefit by consuming โwasteโ materials from other processes.
But once SCMs are added, โthe product becomes a new product; it becomes a blended cement,โ Bergenstock said. โNo one should assume that just because a material is cementitious, it will act exactly as a cement in a pneumatic conveyance system.โ
Some companies with an existing conveying system designed for Portland cement may presume that if supplemental material is added, the product will convey similarly. But instead, conveying may occur at a different capacityโeven with adding only a small percentage of SCMs. โIt doesnโt take very much for this to change the conveyability of the product,โ Bergenstock said.
To ensure the expected results, cement companies should seek out labs that can test the blended productโs particle-size distribution and chemical composition to ensure the reclaim and conveying system will perform as required. For instance, a product with 10 percent of supplemental material will likely convey differently than a product with 30 percent.
โThe message is that (blended cement) can always be conveyed, but the system has to be designed specific to the product being handled,โ Bergenstock said. FLSmidth operates a lab that offers blended-cement analysis, in addition to general fluidizing and conveying testing.
Fluidized floor
Regardless of the material being handled, certain qualities are consistent in the design of pneumatic systems. The centerpiece of such a system is the fluidized floor in all its varieties, and โif you donโt want to deal with moving parts, the fluidized floor is your system,โ Aagard said.
There is no most-popular type of fluidized floor, but different types operate differently. The simplest, an inverted cone or pyramid that feeds product to the center where it drops to a reclaim tunnel under the floor, is also the least expensive. But with an inverted cone, a reclaim tunnel is necessary. The tunnel will require waterproofing or added dome height and fill to get the tunnel above gradeโcosts that should be factored in when considering budget.
A dihedral floor will mobilize product to one side of the floor, and a double-dihedral floor feeds cement to two sides. An obvious advantage with these models is the need for a reclaim tunnel is eliminated as product is fed to the side, not the center, โItโs nice to discharge to the side with all the equipment outside,โ Aagard said, freeing up more room inside for storing product and reducing safety concerns inherent with reclaim-tunnel maintenance.
One perk to the double-dihedral floor is the ability to run an access tunnel under the peak in the floor. Aeration pipe can be run through this tunnel, drastically reducing penetrations to the exterior of the dome wall where pipe would otherwise run around the perimeter.
Companies with existing but dated fluidized floors might opt to renovate their existing floor, which is possible and usually costs less than constructing a new storage facility, Aagard said.
To read the full text, which includes information about pneumatic conveyance and its energy consumption, visit the World Cement website.
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Editor’s note: The following article was published by US Builders Review in its “Best of the United States 2017.” Author […]
Editor’s note: The following article was published by US Builders Review in its “Best of the United States 2017.” Author is Mike Schoch.
The brute strength and space efficiency of Dome Technologyโs domes make them ideal for storing bulk products like grain and wood pellets. In fact, the domes are so strong they can weather hurricane-force winds and tornadoes, which is why the company now builds shelters for school kids and their communities.
The key to doing this, according to Dome Technologyโs vice president of Marketing, Jason Miller, is cutting literal corners.
With their rounded walls, dome-shaped structures have no corners to catch the wind, and flying debris from a storm is more likely to be deflected by a dome than by a flat wall.
โIn the bulk storage world we build on ports next to oceans, lakes and rivers,โ Miller says. โThat means you have a high potential for storm-related disasters.โ Similarly, Dome-shaped structures are useful in the landlocked middle states, which are prone to tornadoes.
When founded in 1975, the Idaho-based company focused on storing potatoes. After word spread about its strong, versatile facilities, Dome Technology became popular for storing commodities like wood pellets, coal, sugar and cement as well.
Miller says the company doesnโt just bank on the shape of the dome. It incorporates safety into the interior design as well. Thatโs because bulk storage facilities can be susceptible to explosion. โDust is your enemy in bulk storage. Once you get dust in the air from wood pellets, grain or coal, a tiny spark can ignite and explode,โ he says.
In massive storage facilities like those found at Drax power station in the United KingdomโDome Technologyโs largest project to dateโa single spark has the potential to ignite 80,000 tons of wood pellets, which would cause a massive explosion.
Thatโs why the facility is equipped with a 90 foot-wide vent at the domeโs peak that allows pressure to be released up and out.
Recently, Miller says the company has pioneered a proprietary circular vent that more evenly absorbs explosive force, further protecting workers and products.
Beyond its safety measures, Dome Technologyโs structures hold more of a product compared to an equivalent-sized rectangular structure or silo. Thatโs a crucial feature for Dome Technologyโs customers who must often build where real estate costs are sky-high.
Though Dome Technologyโs bread and butter is storage, it has built more than 20 FEMA-approved schools and community shelters, primarily in the so-called tornado belt of Iowa, Missouri, Oklahoma and Texas.
โWhen these tornadoes roll through and there are projectiles driving everywhere and 200 mile per hour winds and all the devastation that comes with them, domes withstand the storms extremely well,โ Miller says.
The same qualities that make domes ideal storage facilities also make them great for keeping people safe. In 2015, Dome Technology built a storm shelter that doubles as a gymnasium with locker rooms and offices adjacent to a high school in Webb City, Missouri. The structure can withstand 250 mph winds and will shelter up to 3,000 people.
Miller says that students and parents know โwhen the wolf comes knocking at the door, this is the place to come to.โ
As with its storage facilities, Dome Technologyโs shelters are safe because of their construction as much as their design. To build the domes, workers first inflate a massive PVC membrane, then they spray polyurethane foam on the inside of it, insulating the dome against heat and cold.
The final step involves installing a rebar skeleton against the interior foam and reinforcing it with concrete. The inflated membrane skin is left up even after construction is complete to act as a water barrier. Not only does the construction process keep workers safe during building, it makes the final product sturdy and very easy to modify because it doesnโt have interior walls for support.
โWhat if the school decided it needed a gymnasium instead of classrooms? The school could simply knock out all the interior walls because the dome is self-supporting,โ Miller says.
Because Dome Technologyโs products are so versatile, the company works closely with clients on design. โWe pride ourselves on talking to the customer and combining their ideas with our ideas to get the best solution,โ Miller says.
Miller recalls an instance when Dome Technology were able to design a system that would cost $3 million dollars less than the model a customer thought it wanted.
Despite the unconventional construction process, Miller says most facilities, whether storage or shelter, take as little as three to five months to build. He says traditional facilities just canโt competeโprice- or time-wiseโand believes dome-shaped structures will become more and more common.
Being blunt, he says, โwe feel we can beat the socks off outdated building methods.โ
(Download the PDF of this article)
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According to an article by Progressive Railroading, the new American Crystal Sugar Company dome in Montgomery, Illinois, will boost BNSF […]
According to an article by Progressive Railroading, the new American Crystal Sugar Company dome in Montgomery, Illinois, will boost BNSF Railway Co. efficiency, thanks in part to its location and the ease in receiving shipments from other states.
The article also notes that BNSF anticipates a 10 percent reduction in cycle time for shipping sugar and expects to move almost twice as much sugar to customers each year.
The dome will provide ample sugar storage not available in the area before. Previously, railcars full of sugar would deliver product to various receivers in Chicago that didnโt always have sufficient room to store it, resulting in railcars having to wait to unload.
Dome Technology constructed the dome, which stands 134 feet tall and 183.7 feet in diameter and can store 60,000 metric tons of sugar. Although ACSC owns the facility, United Sugars Corporation oversees operations.
To read the full Progressive Railroading article, click here.
Photo via progressiverailroading.com
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As part of the 12th annual Outstanding Shotcrete Project Awards held Jan. 17 in Las Vegas, Nevada, the American Shotcrete […]
As part of the 12th annual Outstanding Shotcrete Project Awards held Jan. 17 in Las Vegas, Nevada, the American Shotcrete Association awarded Dome Technology with an honorable mention for the construction of its corporate office in Idaho Falls, Idaho.
โThe office is a stunning achievement in concrete thin-shell construction. We gave it a 100-plus-year roof, water tight and fully insulated, and we uniquely heat and cool the building utilizing geothermal energy,โ said Dome Technology Vice President of Engineering Jason South.
South and Vice President of Construction Bryan Butikofer made a presentation about the project and accepted the award at a banquet. According to the ASA website, the awards program showcases the versatility and benefits of the shotcrete method. ASA annually recognizes projects of note where shotcrete is significant to the overall scope of work.
Dome Technology sought an architectural style for its new office that would complement its cutting-edge engineering and construction. โItโs a modern office with an industrial flair,โ project manager Daren Wheeler said, adding that visitors canโt help but notice the open freespan area.
Two noteworthy features in the office are the heating and cooling systems, both of which are housed within the concrete. All heating is achieved through in-floor radiant heat with hot water routed through the floor in multiple zones for flexibility in climate control.
For more information on Dome Technology’s corporate office and its construction, click on our Articles section.
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Dome Technologyโs previous corporate office was a domeโan obvious choice since thatโs what the company has been building for 40 […]
Dome Technologyโs previous corporate office was a domeโan obvious choice since thatโs what the company has been building for 40 years.
But since the office was built in the mid-1980s, the technology was outdated, the building was aging, and natural light was lacking. Management knew a new facility could be an asset for business, both internal and external.
โWe wanted to be able to show people what we could do. We bring in people from all over the world to meet with us, and we needed an upgrade,โ said Daren Wheeler, who acted as project manager for the new office.
The company builds bulk-storage and architectural domes all over the world and specializes in customized solutions to meet customer needs. Since โtechnologyโ is part of its name, Dome Technology sought an architectural style that would complement its cutting-edge engineering and construction. โItโs a modern office with an industrial flair,โ Wheeler said, adding that visitors canโt help but notice the open freespan area.
That freespan is made possible in part based on shotcrete construction. Shotcrete was the primary structural component for construction, and the shotcrete work followed Dome Technologyโs standard application process: A round airform was inflated, and polyurethane foam insulation was applied inside, forming a layer two inches thick. To the foam, workers applied a network of two-inch-square metal plates called stickers with rods attached to their centers. A final layer of foam insulation was applied, with premat steel reinforcing placed on top and connected to these sticker rods.
With this foundation, the dome was ready for shotcrete. Multiple applications of shotcrete and steel rebar were applied until necessary thickness was achieved and the dome was superior in its strength.
The continuous concrete shell protects the interior from external precipitation and provides necessary strength that complements the domeโs double curvature, resulting in a self-supporting structure free of interior supports.
โThe biggest (advantage) with a concrete dome in an architectural application is thereโs no interior load-bearing walls. Down the road, thereโs virtually nothing stopping you from changing the entire interior,โ Wheeler said.
The shotcrete dome coupled with the waterproof membrane counters common breakdown issues in concrete resulting from lack of insulation, extreme temperature fluctuations, and exposure to water. With the way itโs built, โthereโs no limit to the life span to this building,โ Wheeler said.
Burns Concrete of Idaho Falls, Idaho, USA, provided the shotcrete for the project, an easy choice based on a long-term working relationship between the two companies. โTheyโre really on the cutting edge of mix designs, so they fit our style of construction very well, and they have good quality-control measures in place,โ Wheeler said.
Two noteworthy features in the office are the heating and cooling systems, both of which are housed within the concrete. All heating is achieved through in-floor radiant heat with hot water routed through the floor in multiple zones for flexibility in climate control.
The innovative cooling system is radiant too. According to Justin Judy, a principal at Engineering Systems Solutions (ES2) who performed engineering on the project, cooling begins with the concrete shell absorbing heat. โAs lights are turned on, as people are in the building, and as computers are turned on, that heat rises, and the shell acts as a thermal battery. It essentially collects that heat, so you donโt necessarily have to air condition the building because the heat is going into the shell,โ Judy said.
Because the shell holds heat exceptionally well, coming up with a way to discharge the energy was necessary. The ES2 team designed a system that circulates 55-degree Fahrenheit (12.8 degrees Celsius) ground water from an exterior well through three miles of PVC tubing routed within the shell. As the water flows through the shell, it collects the heat, then returns to the aquifer through an injection well. โWe arenโt paying to air condition a large portion of the dome because weโre using ground water to do it,โ Judy said.
Besides long-term cost savings, the heating system provides an ideal work environment for employees. โParticularly with all the openings we have, itโs pretty remarkable we can stay as warm as we do with just the radiant heating,โ said Dome Technology Vice President of Sales Rod South. โBecause the dome shell and the floor are integrated into one concrete thermal mass and we have the radiant heating throughout, it stays nice and toasty through the winters,โ which can dip to 20 below zero Fahrenheit (-28.9 degrees Celsius).
The heating and cooling systems provide an effective way to show potential customers the efficiency of heating and cooling a dome. โJust having the concrete building reduces your cooling costs in the summer because it absorbs the heat,โ Wheeler said.
To further push aesthetics, the dome was finished with windows that provide views from every angle. โBecause there are no (structural) walls, the office feels very open and very big, and it feels like thereโs no sense of confinement, particularly with so much glazing and since you can see from end to end and whatโs in front of you and whatโs behind you,โ South said.
Dome Technology builds domes of varying geometries, and the corporate office showcases an elliptical dome thatโs better acoustically and aesthetically.
โWe feel really proud to be able to show people the office. Itโs a highlight of our shotcrete work, and it also stands to show what weโre capable of. Because this dome is nicely finished, (customers) have an inherent trust that what weโre going to deliver to them is going to be a quality product as well,โ South said.
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Dome Technology has finished constructing a dome standing 134 feet tall and 183.7 feet in diameter for American Crystal Sugar […]
Dome Technology has finished constructing a dome standing 134 feet tall and 183.7 feet in diameter for American Crystal Sugar Company. The dome can store 60,000 metric tons of sugar, and although ACSC owns the facility, United Sugars Corporation oversees operations. Click here for a video about the dome and its systems.
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.
Client requests + customization
The dome is a first for American Crystal Sugar Company, which previously relied upon concrete silos and steel Weibull bins. According to Aaron Bjerke, who oversees business development for ACSC, the cost of constructing a dome versus concrete silos was equivalent per unit stored, but savings could be found in the material-handling systems. Because the company will be able to achieve its storage needs with one dome, just one handling system will be installed, as opposed to a redundant cost of one material-handling system per silo.
Meeting customer expectations
In addition to building the dome, Dome Technology installed the reclaim screw, a clean-sweep model made of stainless steel to complement food-safe requirements. A food grade-quality coating was sprayed on the entire inner dome shell, and the applied VersaFlex product ensures cleanliness in storage. The dome also features temperature and humidity control, a dust-collection system, and explosion panels.
According to an ACSC press release, the dome will not be attached to a producing sugar factory, making it the United Statesโ largest freestanding sugar-storage facility.
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In December Port City Daily in Wilmington, North Carolina, featured Envivaโs latest portside project, highlighting the eco-friendly approach to energy production that […]
In December Port City Daily in Wilmington, North Carolina, featured Envivaโs latest portside project, highlighting the eco-friendly approach to energy production that wood pellets provide.
The article details Envivaโs 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 domeโs 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 Envivaโs 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 freeโthe fewer the horizontal surfaces, the fewer places for dust accumulation.
For more information on domes and wood-pellet storage, click here.
Image via WECT.