Meeting world demand for clean coal and biomass storage
Worldwide demand for clean coal and sustainable biomass storage alternatives has surged in recent years. Dome Technology LLC continues to provide timely collaborative state-of-the-art engineering and construction services for dome storage solutions.
If Charles Dickens’ epic work, A Tale of Two Cities, were written today about meeting worldwide demand for clean coal and sustainable biomass storage alternatives, he might have called his book, A Tale of Two Dome Projects. And he likely would have altered the lead-in paragraph to read,“It was the best of times, and it was the best of times,” as illustrated by the successful stories of two energy-related storage projects recently engineered and constructed or to be constructed by Dome Technology LLC, Idaho Falls, Idaho.
One of the projects is a clean coal storage terminal facility for KUMHO Terminal Operation Co. Ltd.’s NAK-PO Coal Terminal Project now under way in Yeosu, Korea. The other is a recently completed project for Savannah Bulk Terminal LLC – Georgia Biomass LLC’s wood pellet storage and handling facility in the Port of Savannah, Georgia. The following stories tell how each project’s unique challenges, needs, and concerns have been proactively resolved through comprehensive design-build collaborative undertakings with Dome Technology to help ensure the best of times for both owners.
 
KUMHO TERMINAL OPERATION CO. LTD. NAK-PO COAL TERMINAL,YEOSU, KOREA KUMHO
Terminal Operation Co. Ltd. (KTO) has begun construction of its NAK-PO Coal Terminal in Yeosu, a port city along the southern coast of Korea. The project is a terminal import distribution facility with a total future storage capacity of 570,000 metric tonnes. The current project consists of three 80,000-tonne 184’ diameter x 195’ high reinforced concrete Dome Technology DomeSilosTM with five pass-through tunnels fed by mechanical rotary plough reclaimers for a total storage and handling capacity of 240,000 tonnes of coal.
Meeting challenges and concerns
KTO has very tight footprint requirements for the proposed storage. KTO originally considered a concrete silo with a steel conical roof, but after meeting with Dome Technology in early 2010, selected a DomeSiloTM structure with a rotary plough reclaim system at the bottom of the coal pile. A major concern for KTO was its unfamiliarity with the new technology of a DomeSiloTM. Its concerns were quickly resolved after it visited other constructed DomeSiloTM projects in other parts of the world. KTO’s decision to use a Dome Technology DomeSiloTM over a conventional concrete silo was also based on the following advantages:
  • elimination of moisture and dust concerns;
  • safe construction methods;
  • lower overall height;
  • air tight construction;
  • economical support of very large apex loads for conveyors and head houses;
  • significantly reduced construction schedule;
  • fully waterproof construction; and
  • ‘green and clean’ appearance.
 
Selecting the right reclaim system
While various reclaim systems were available, KTO selected a mechanical rotary plough system that travels the entire length of each of five below- grade tunnels that feed onto tunnel belt conveyors. With chevron hoppers positioned above-grade between the tunnels, this reclaim configuration provides 100% live reclaim. Other available reclaim system options for clean coal may include a gravity feed reclaimer and a mechanical horizontal screw reclaimer, or a mechanical stacker reclaimer
(illustrated below), as well as other options.
The overall concept of KTO’s operation includes a ship unloading system, belt conveyors filling and reclaiming from the DomeSiloTM, systems to monitor and
suppress explosion and fire, and train and truck loading systems. Dome Technology provided schematic and design development for the storage layout and designed the DomeSiloTM, tunnels, internal chevron system, interior rotary plough covers and supporting piers and curbs on the apex for the head house. Dome Technology will provide the technical expertise and construction supervision to construct the dome-related structures. The apex of the DomeSilosTM are designed to support an excess of 1.2 million pounds from the conveyors and head house system. The design-build contractor, eTEC E&C Ltd. (Korea), provided the design of all the material handling and control systems.
 
SAVANNAH BULK TERMINAL LLC AND GEORGIA BIOMASS LLC,WOOD PELLET STORAGE,SAVANNAH,GEORGIA
Savannah Bulk Terminal LLC-Georgia Biomass LLC has completed two 190’ diameter x 105’ high Dome Technology reinforced concrete DomeSilosTM at its bulk pellet terminal storage/handling facility in the Port of Savannah, GA. The two domes combine for a total storage capacity of 50,000 metric tonnes using front-end loaders to assist a gravity-feed to a single-tunnel reclaim conveyor system.
 
Meeting challenges and concerns
In late 2008, Savannah Bulk Terminal – Georgia Biomass (SBT–GB) began considering storage solutions for stockpiling 50,000 tonnes of wood pellets at its port facility in Savannah, GA. SBT–GB originally considered an enormous A-frame structure supported by pile foundations, similar to a pellet storage facility in Panama City, FL. After meeting with Dome Technology in early 2009, SBT-GB’s Frank Peeples, Jr., very quickly became interested in the Dome Technology DomeSilo storage concept. There were many apparent advantages to the dome over flat storage, which ultimately led SBT–GB to choose domes over the A-frame structure. Some of these advantages include:
  • decreased real-estate (footprint) requirements;
  • elimination of need for expensive pile foundations;
  • higher volumetric storage capacity;
  • competitive cost compared with A-frames;
  • high live reclaim percentage;
  • fully waterproof construction;
  • lack of dust-accumulating internal structural elements;
  • high insulation factor to reduce thermal fluctuations; and
  • ‘green and clean’ look of dome structures.
Selecting the right reclaim system
While various reclaim systems were available, SBT–GB selected a gravity feed system through five in-floor hoppers in each DomeSiloTM which feed into a below-grade tunnel system onto belt conveyors. This reclaim configuration allows for 50% live reclaim. Supplemental reclaim is assisted by front-end loaders pushing pellets into the in-floor hoppers. Other available reclaim system options for wood pellet storage and handling would be a mechanical horizontal screw reclaimer and a vibratory floor reclaimer as illustrated in the following figures.
The overall concept of SBT-GB’s operation includes a rail receiving station, domes and tunnel with filling and reclaim belt conveyor systems, and conveyor delivery systems to port ship loading facility. Dome Technology’s structural and mechanical design scope included:
  • material handling from rail pit through dome product reclaim;
  • mechanical,structural,electrical;
  • DomeSilosTM and head house;
  • life safety (accesses and egresses);
  • conveyors;
  • tunnel;
  • rail pit;
  • dust control;
  • dome interior temperature and humidity monitoring; and
  • fire suppression.
SUMMARY
Although the KUMHO NAK-PO Coal Terminal in Korea and the Savannah Bulk Terminal – Georgia Biomass wood pellet storage projects are on opposite sides of the world and have widely divergent challenges, needs and concerns, the tale of their two projects promises the best of times for both owners who have been able to find synergistic solutions and customized engineering and construction outcomes by collaborating with Dome Technology LLC and its engineering partner Engineering System Solutions (ES2) of Idaho Falls, Idaho.