The utilization of coal in modern power generation faces dual challenges: achieving high efficiency while minimizing environmental impact.
One promising approach is pressurized oxy-fuel combustion, in which coal is burned under elevated pressure in O₂/CO₂ environments, facilitating efficient CO₂ capture and reducing pollutant emissions such as SO₂ and NOₓ. To advance this technology, a deeper understanding is required of how coal char physicochemical properties and coal ash mineral transformations evolve under pressurized pyrolysis and combustion conditions.
The article “Investigation on the physicochemical properties of coal char during pressurized pyrolysis and the mineral transformations of coal ash during pressurized O₂/N₂ and O₂/CO₂ combustion” (Lei et al., 2020) addresses this challenge. It systematically explores how pressure, temperature, and combustion atmosphere affect both the structural evolution of coal char and the phase transformations of coal ash minerals. In particular, the study compares air combustion (O₂/N₂) and oxy-fuel combustion (O₂/CO₂) under pressurized conditions to evaluate implications for CO₂ mitigation strategies.
High-pressure tube furnace
The OTF-1200X-S-HP-30A high-pressure tube furnace is a specialized laboratory furnace designed to combine high temperature, elevated pressure, and controlled gas atmospheres. This furnace served as the core experimental platform, enabling researchers to replicate conditions relevant to advanced pressurized oxy-fuel combustion systems.
Unlike conventional tube furnaces, which operate primarily under atmospheric pressure, the OTF-1200X-S-HP-30A can maintain pressures up to 6 MPa and temperatures up to 1100 °C while precisely controlling the gas composition (O₂, N₂, CO₂, and their mixtures). This capability allows for the simulation of realistic combustion and pyrolysis conditions, which are critical for studying physicochemical changes in coal char and mineral transformations in coal ash.
Using this furnace, the study investigated how temperature, pressure, and gas atmosphere influence coal char decomposition and ash mineralogy. Key findings indicate that furnace temperature plays a more significant role than pressure in driving mineral transformations, and that while the main mineral compositions in ash remain similar between oxy-fuel (O₂/CO₂) and air combustion (O₂/N₂), their relative abundances vary due to differences in combustion mechanisms and temperatures.
The OTF-1200X-S-HP-30A enabled precise, reproducible control over experimental parameters, ensuring that coal chars and ashes could be prepared under well-defined, pressurized environments suitable for detailed FTIR and XRD analyses. Without this high-pressure, controlled-atmosphere furnace, replicating the conditions required for this investigation—and thereby deriving meaningful insights into pressurized combustion processes and CO₂ capture strategies—would not have been possible.
MTI’s OTF-1200X-S-HP-30A Model
Working Temperature : ≤ 1100 °C
Heating Rate : ≤ 10 °C/min
Temperature Control Accuracy : ± 1 °C
Working Pressure (in side the tube) :
- 20 MPa at heating temperature 800 °C
- 12 MPa at heating temperature 900 °C
- 6 MPa at heating temperature 1000 °C
- 4 MPa at heating temperature 1100 °C
Tube Material : Ni-based superalloy (Waspaloy or equivalent)
Tube Dimensions : 30 mm O.D. x 12 mm I.D. x 580 mm L (50 mm O.D. option available)
Atmosphere compatibility : O₂, N₂, Ar, He (safe gases; consult MTI for others)
Temperature control: PID programmable controller with type K thermocouple
Safety : Digital pressure monitoring, overpressure protection, over-temperature cut-off
Power Requirement : 2.2 kW, AC 208–240 V single-phase (120 V option available)
Control & Monitoring : Digital pressure monitor; optional PC control with Labview-based software
Certification : CE certified (NRTL/CSA optional)
In summary, the OTF-1200X-S-HP-30A furnace is central to this research, providing the controlled high-temperature, high-pressure, reactive gas environment required to explore coal char behavior and ash mineral transformations under pressurized pyrolysis and combustion, directly supporting the study’s relevance to modern oxy-fuel power generation and CO₂ mitigation technologies.
To learn more about the OTF-1200X-S-HP-30A furnace, reach out to us at contact@accessr-energy.eu
