Storage Silo for Calcined Petroleum Coke
- Solid structure & strong resistance to corrosion
- The most cost-effective investment
- Short construction period
Steel silo is well suited for storing all grades of the Calcined Petroleum Coke (CPC). Our enclosed storage system solves many important environmental issues. Environmental requirements will be fully met by it. In addition, economics and operational benefits are usually the main reasons to choose for it.
How does a steel silo for the storage of calcined petroleum cokework?
Loading position is in the center of silo roof through a conveyor. The coke is conveyed through the inlet hopper down to the equalizing augers by a centrally telescopic chute and a dust lock at the outlet of the chute. The silo loading is accomplished by the equalizing augers on the auger frame which is suspended by steel wires from the slewing bridge. The auger frame can be lifted or lowered by a winch system. The equalizing augers can convey the coke outwards to the silo wall, while a simultaneous stepwise slewing of the auger frame takes care of loading the silo in evenly spread layers.
Unloading of the silo is initiated by the weigh feeders arranged centrically at the silo bottom, which feeds the coke onto a belt conveyor that can convey the coke of several silos simultaneously. The unloading coke causes a central core flow zone in the silo. The augers are now rotating in the reverse direction and convey the coke to the central flow zone.
Dust and fire protection
Reducing danger potential has been achieved by a dust extraction and an air tight enclosure of the silo which the former is reached by keeping an under-pressure inside the entire inlet chute of the silo and the latter makes it vacuumed by dust extraction.
The entry of the air at the bottom of the silo is restricted by the weigh feeders filled with material. Air penetration into the coke is limited to the upper surface. The oxygen concentration in the coke at the surface is clearly under 21 %. Due to natural ventilation, no hazardous CO or CH4 gases or oxygen deficiency above the coke surface can evolve.
At the auger frame near the coke surface and the roof area CO and CH4 detection sensors are installed for gas detection to assure that gas concentrations will be below explosion limits. A ventilation device is controlled by gas monitoring system. When the coke temperature exceeds the temperature limit, the system will turn off automatically.
In addition, fire hazards must be controlled in case of an emergency. Fire extinguishing devices must be installed in cooperation with local fire brigades authorities.
The unloading is accomplished by an ongoing conveyor underneath the silos. The conveyor is fed in each by the weigh feeders arranged at the bottom. The system creates a continuously adjustable blending ratio of the silos from 1:1 to 1:4. Coke is reclaimed in layers by the "last in first out" principle. During coke unloading only the central core flow zone is in motion, whereas 90% of the silo content remains in a calm and compacted condition, avoiding loosening and separating. Additional homogenization of the unloaders, the coke is achieved by means of this loading/unloading procedure.
Already two silos will meet to a large demands related to blending possibilities. The grades are divided in two parcels with the similar quality standards. The possibilities for creating blending ratios will improve more than proportionally if three or more silos are gotten. As power plant (or as anode plant) availability requirements become more demanding, so does the demand for controlling the quality blend of the coke.
The ability to change the coke blending ratio is a condition, in order to getting the performance requirements. Usually the coke actual quality characteristics are only recognized during the process, because coke researches are not available or are incomplete and/or do not apply. In these conditions the damage can only be limited.
Economics of silo storage of the CPC
The costs and savings of silo storage of the CPC are greatly important. All costs including the total service life of the unit have to be considered into it. The operating cost includes obvious factors like energy consumption, maintenance, etc. and the hidden costs just like product loss and quality loss by dust emission, self heating and savings by purposeful blending. These are indeed substantial cost savings. Because the storage silos and its related building allow for the segregation of the CPC by grade and provide the capability to blend the CPC as customer requirements Storage capacity such as an anode plant usually reaches an average of 10%-15% of its annual throughput, resulting in about 50,000-100,000tons to be distributed over three or four silos. Using the silos is the best cost-saving choice.
About Calcined Petroleum Coke
Calcined petroleum coke, CPC for short, is a high purity carbon material that is produced by heating green petroleum coke to expel moisture, volatile matter and others impurities and increase its electrical conductivity. The CPC is the product of the coker in a crude oil refinery, which has a sponge-like structure which plays an important role in the making of anodes. The CPC is used for electrolytic aluminum anode and anode paste, carbon industry production of carbon, graphite electrode, smelting industry, such as silicon and fuel. The primary aluminum industry is the major consumer of the CPC, representing approximately 80% of the demand for this carbon material. Besides, the CPC is used extensively in other industries, for example, cement plant, ceramic industries, briquette industries, glass industries, etc.
For silo storage of the CPC, the conditions for the environmental protection are fulfilled; the operational requirements of coal blending are fulfilled; the maintenance expenditure compared with the other storage methods is evaluated positively.
With strong engineering expertise and project management skills, Flyer Company can provide the best solutions for our clients. Our recognized expertise is a strategic asset that drives our competitiveness. Technical experts have developed knowledge and skills that are industry benchmarks. If you need our service, please feel free to contact with us.