Co-firing zero-carbon fuels as an effective emission reduction strategy in coal combustion processes has garnered widespread attention. This paper proposes utilizing the combustion performance of oxy-hydrogen gas derived from zero-carbon fuels to address issues related to low-concentration coal powder combustion and nitrogen oxide emissions. A test apparatus for coal powder combustion initiated by oxy-hydrogen gas flames was constructed, and experimental and simulation methods were employed to study the impact of oxy-hydrogen gas flame initiation on the temperature inside the combustion chamber, coal powder gasification combustion reactions, and nitrogen oxide emissions. The results indicate that with an excess air coefficient of 0.8, as the oxy-hydrogen gas flow rate increased from 0.022 kg/h to 0.789 kg/h, the average temperature inside the combustion chamber increased from 801 K to 1459 K. The volatile matter release rate and its combustion reaction rate increased, leading to a decrease in volatile matter content. The peak concentration of volatiles was shifted from a position of 68 mm to 7 mm, and the proportion of C_char–H₂O reaction increased from 5% to 34%. NO emissions decreased from 132 ppm to 68 ppm, and the rate of reduction in NO emissions decreased from 15.38% to 5.49%.

This paper investigated the influence of surface internal energy instability caused by the gravitational tilt angle on solutocapillary convection. The results showed that the spatio-temporal evolution of solutocapillary convection in a non-axisymmetric liquid bridge was divided into three stages under different gravitational tilt angles, “the initiating stage near the upper corner”, “development to the intermediate height”, and “shrinking toward the bottom corner”. The non-equilibrium of the left or right interface curvature caused by internal energy instability promotes the distortion of the cell flow structure. The concentration gradient on the far-earth side increases first, due to the gravitational tilt angle. With the increasing gravitational tilt angle, the lateral extension of the cell flow is inhibited. The transverse/longitudinal velocity components are suppressed; however, the velocity gradient near the boundary is increased, and the uniformity of the velocity distribution in the center of the liquid bridge is improved. The axial component of the Bond number decreases in a small range (Bo′ = 1→0.98) with the internal energy instability, however, which has a significant effect on surface flow. Therefore, in the initiation and development stages of solutocapillary convection, the decay rate of the Marangoni number respectively decreases and increases with the increasing Bond number. The axial component of the Bond number decreases in a small range with the internal energy instability, which has a significant effect on the solute Marangoni number (Ma_c). In the initiation stage of solutocapillary convection, the decay rate of the Ma_c decreases with the increasing Bond number. Its change law is the opposite in the development stage of solutocapillary convection.

Hydrogen energy is an important carrier for energy terminals to achieve green and low-carbon transformation. Hydrogen, as a carbon-free fuel, has great research and development value in the field of thermal power generation. This article proposes a solution for the stable combustion of coal powder using Oxy-hydrogen Gas ignition technology. An Oxy-hydrogen Gas flame injection coal powder combustion testing device was constructed to experimentally study the temperature distribution in the combustion chamber under Oxy-hydrogen Gas ignition technology, with primary air coal powder concentrations of 0.27, 0.32, and 0.36 (kg coal powder/kg air), as well as the concentration changes of volatile CO emissions during the ignition of coal powder using both Oxy-hydrogen Gas and CH₄ flames. The sensitivity of the NO generation during coal gasification combustion under the Oxy-hydrogen Gas ignition was simulated and analyzed. The results show that at a coal powder concentration of 0.32 (kg coal/kg air) and an Oxy-hydrogen Gas flow rate of 2.1 L/min, the combustion effect of coal powder is the best, and the highest combustion chamber temperature can reach 1156 K; when the concentration of coal powder varies within a range from 0.32 to 0.27, the combustion chamber temperature can be maintained at around 850K, achieving stable combustion conditions for coal powder. The only product generated by the Oxy-hydrogen Gas combustion is high-temperature water vapor, which helps the rapid gasification of coal powder and releases a large amount of volatile CO, which is beneficial for the ignition and stable combustion of coal powder.

The effect of Brown’s gas on the gas-phase tar cracking behavior, carbonic oxide (CO) production rate, and gaseous product temperature during the pine wood pyrolysis was preliminarily explored. By the application of cold trapping and gravimetric methods, it was found that Brown’s gas reduces the energy barrier of thermochemical conversion for gas-phase tar, widens the temperature range of gas-phase tar accelerated cracking, and increases the cracking rate. When the pyrolysis temperature increases by 1 °C, the average cracking rate of gas-phase tar increases from C = 4.58 g⋅Nm⁻³ (flow volume ratio of Brown’s gas to nitrogen, X_{(Brown’s gas)}:N₂ = 0%) to C = 4.8 g⋅Nm⁻³ (X:N₂ = 1%) and C = 5.02 g⋅Nm⁻³ (X:N₂ = 5%). While participating in the deep cracking of gas-phase tar, Brown’s gas reduces the conversion energy barrier of the gas-phase tar to CO. The CO production rate rises from the initial 1.87% (X:N₂ = 0%) to 4.22% (X:N₂ = 1%) and 5.52% (X:N₂ = 5%) per 1 °C of increased pyrolysis temperature. The consumption of Brown’s gas is 0.32 m³ per 1 g⋅Nm⁻³ of gas-phase tar cracking within the pyrolysis residence time of 30 min.