Yalin Wang

This paper presents the experimental and numerical study of the laminar burning velocity and pollutant emissions of the mixture gas of methane and carbon dioxide. Compared to previous research, a wider range of experimental conditions was realized in this paper: CO₂ dilution level up to 60% (volume fraction) and equivalence ratio of 0.7–1.3. The burning velocities were measured using the heat flux method. The CO and NO emissions after premixed combustion were measured by a gas analyzer placed 20 cm downstream of the flame. The one-dimensional free flames were simulated using the in-house laminar flame code CHEM1D. Four chemical kinetic mechanisms, GRI-Mech 3.0, San Diego, Konnov, and USC Mech II were used in Chem1D. The results showed that, for laminar burning velocity, the simulation results are all lower than the experimental results. GRI Mech 3.0 showed the best agreement when the CO₂ content was below 20%. USC Mech II showed the best consistency when the CO₂ content was between 40 and 60%. For CO emission, these four mechanisms all showed a small error compared with the experiments. When CO₂ content is higher than 40%, the deviation between simulation and experiment becomes bigger. When the CO₂ ratio is more than 20%, the proportion of CO₂ does not affect CO emission so much. For NO emission, when the CO₂ content is 40%, the results from simulation and experiment showed a good agreement. As the proportion of CO₂ increases, the difference in NO emissions decreases.

This paper presents comparative research on the combustion of coal, wheat, corn straw (CS), beet residues after extracting sugar (BR), and their blends, coal–corn straw blends (CCSBs), coal–wheat blends (CWBs), and coal–beet residue blends (CBRBs), using thermogravimetric (TG) analysis under 10, 20, 30, 40 and 50 °C/min. The test results indicate that CS and wheat show better combustion properties than BR, which are recommended to be used in biomass combustion. Under the heating rate of 20 °C/min, the coal has the longest thermal reaction time when compared with 10 and 30 °C/min. Adding coal to the biomass can improve the burnout level of biomass materials (BM), reduce the burning speed, and make the reaction more thorough. The authors employed the Flynn–Wall–Ozawa (FWO) method and the Kissinger–Akahira–Sunose (KAS) method to calculate kinetics parameters. It was proven that overall, the FWO method is better than the KAS method for coal, BM, and coal–biomass blends (CBBs), as it provides higher correlations in this study. It is shown that adding coal to wheat and BR decreases the activation energy and makes conversion more stable under particular α. The authors selected a wider range of biomass raw materials, made more kinds of CBB, and conducted more studies on different heating rates. This research can provide useful insights into how to choose agricultural residuals and how to use them.

A variety of clean-energy heating systems were applied in China with multiple energy systems complementing each other according to local conditions. The purposes are pushing forward a supply-side structural reformation; coordinating the utilization of waste heat in high energy-consuming enterprises; realizing the energy cascade use; improving the ecological environment. This paper introduces a coupling energy station of 10 new clean-energy heating systems located in the central city district in Jinan. It could make full use of renewable energy and ensure high-quality heating in winter, increase energy utilization efficiency, replace fossil fuels, and reduce primary energy consumption. Furthermore, it can make up for the deficiency of a single system and reduce the emissions from fossil fuels. After comparing the heating parameters, the authors got the conclusions that the heating area of this new energy system is equal to the traditional coal system burning 9,508.032 tons of standard coal, which means in each heating season, about 7,233.33 × 10⁷ m³ of waste gases, 45.64 tons of SO₂ emissions, 69.586 tons of NO_x emissions, and 139.52 tons of soot emissions will be avoided. So, this new energy heating system is safe, stable, energy-saving, environmentally friendly, and effective, which can completely replace the heating system of traditional coal-fired boilers.