Research Article
The Impact of Pit Ventilation System on Protective Isolation Walls in Coal Mine
Safer Demirović*
,
Jelena Marković
Issue:
Volume 14, Issue 2, April 2026
Pages:
17-26
Received:
2 April 2026
Accepted:
14 April 2026
Published:
30 April 2026
Abstract: Underground coal mining is impossible without the use of protective pillars or protective isolation walls. Regardless of the method of coal mining (longwall method, room and pillar etc.), they all require the use of pillars or protective isolation walls. Their application is present in the exploitation of all types of coal. Today, the design of pillars and protective isolation walls is carried out in the same way. All of them, regardless of their physical and mechanical properties or the applied excavation method, undergo changes over time. Changes can occur due to mechanical damage (mining, rockfall, vibrations due to transport, gas outbursts, etc.) or due to the influence of the pit ventilation system. Although the influence of the ventilation system of the pit on the protective insulation walls is established and known, it has been very little addressed and treated in the literature or concrete research. After the formation of a pillar or isolation wall, under the influence of the pit ventilation system, moisture and gases begin to be released from it, and the cohesive and adhesive forces in it weaken, which also leads to rheological changes. It has been established that in isolation walls where moisture is periodically or constantly introduced and increased for some reason, most often in order to eliminate coal dust, the intensity of rheological changes is lower than in those where this is not done. The paper presents the results of research into the changes that occurred in protective insulating walls used in brown coal mining due to the influence of the pit ventilation system over a certain period of time. Changes in the design of protective columns and insulating walls, taking into account the influence of the pit ventilation system on them, are also proposed.
Abstract: Underground coal mining is impossible without the use of protective pillars or protective isolation walls. Regardless of the method of coal mining (longwall method, room and pillar etc.), they all require the use of pillars or protective isolation walls. Their application is present in the exploitation of all types of coal. Today, the design of pil...
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Research Article
Process Simulation of a 5,000 to 30,000 bbl/Day Modular Hydroskimming Refinery for Selected Nigerian Crude Oils Using Aspen HYSYS
Issue:
Volume 14, Issue 2, April 2026
Pages:
27-36
Received:
15 April 2026
Accepted:
29 April 2026
Published:
19 May 2026
DOI:
10.11648/j.ogce.20261402.12
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Views:
Abstract: Process simulation, design evaluation, and techno-economic analysis of a modular hydroskimming refinery with a processing capacity of 5,000–30,000 bbl/day for selected Nigerian crude oils (Yoho, Bonga, and Qua Iboe) using Aspen HYSYS was considered in this research. Crude oil assays were characterized into pseudo-components using the Peng–Robinson equation of state to accurately represent thermodynamic behaviour. The refinery configuration comprised a Crude Distillation Unit (CDU), naphtha stabilization and splitting units, a naphtha hydrotreating reactor, and a catalytic reforming unit. Simulation results demonstrated a linear increase in product yields with increasing throughput, confirming steady-state operability and scalability across the evaluated capacity range. Product distribution analysis revealed that Bonga crude (API 27.7°) yielded higher heavy fuel oil fractions exceeding 30–35 wt%, while Qua Iboe crude (API 37.3°) produced higher yields of light and middle distillates, with naphtha and kerosene fractions reaching approximately 25–35 wt%. Yoho crude (API 41°) exhibited intermediate behaviour, with balanced distribution across product streams. The CDU operated effectively within a temperature range of 104–644°F and pressure range of 20–49 psig, ensuring efficient fractionation. The hydrotreating unit achieved optimal performance at 340°C and 25 bar, while the catalytic reformer operating at 500°C and 15 bar produced high-octane reformate with stable hydrogen recycle. Economic analysis indicated that capital cost increased from approximately $26 million at 5,000 bbl/day to $78 million at 30,000 bbl/day, while the unit capital cost decreased from about $5,200/bbl/day to $2,600/bbl/day, demonstrating significant economies of scale. This research confirms that modular hydroskimming refineries are technically viable, operationally stable, and economically scalable for processing diverse Nigerian crude oils, providing a strategic solution for decentralized refining and energy security enhancement.
Abstract: Process simulation, design evaluation, and techno-economic analysis of a modular hydroskimming refinery with a processing capacity of 5,000–30,000 bbl/day for selected Nigerian crude oils (Yoho, Bonga, and Qua Iboe) using Aspen HYSYS was considered in this research. Crude oil assays were characterized into pseudo-components using the Peng–Robinson ...
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