The tremendous increase in energy demand due to increased population and rapid economics results in an increased level of atmospheric pollutants and global warming. The global shift to the use of renewable clean energies still has some restrictions in terms of the availability of the advanced reliable technologies and the cost of application compared to conventional fossil fuels. Until we can have this full conversion to renewables, the development of novel techniques for clean combustion of fossil fuels is appreciated. Forced by the simultaneous increased pressure of strict emissions regulations and the target of limiting the global warming to 2 °C, gas turbine manufacturers developed novel combustion techniques for clean power production in gas turbines as per the present review study. These novel techniques depend either on modification in the existing combustion system or developing novel burners for clean power production. In this review, different clean combustion techniques are presented including ...

Review of Novel Combustion Techniques for Clean Power Production in Gas Turbines

Energy recovery from cross-linked polyethylene wastes using pyrolysis and CO2 assisted gasification

Ignition and burnout characteristics of semi-coke and bituminous coal blends were investigated by thermogravimetric analyzer and drop tube furnace. The results showed that the ignitability index and the comprehensive combustion characteristic index of the blends decrease as the blending proportion of semi-coke increases, but the average activation energy of the blends increases gradually. Ignition mode of bituminous coal is changed from homogeneous to hetero-homogeneous ignition with the increasing of semi-coke content in the blends. When the mixing proportion of semi-coke is lower than 45%, the burnout rate is lower than the weighted value in the early stage of combustion and gradually higher than the weighted value with the development of combustion process. However, the burnout is always lower than the weighted value to mix with 67% semi-coke. Increasing furnace temperature from 850 °C to 1050 °C can improve the mid-term reaction process, alleviate the negative effects of semi-coke on the co-combustion process and increase the burnout rate. So less than 45% semi-coke blending ratio and increasing furnace temperature are recommended for semi-coke and bituminous coal co-combustion.

Experimental investigation on ignition and burnout characteristics of semi-coke and bituminous coal blends

Experimental investigation and demonstration of pilot-scale combustion of oil-water emulsions and coal-water slurry with pronounced water contents at elevated temperatures with the use of pure oxygen

The emission of anthropogenic carbon dioxide (CO2) as a result of fossil fuel burning is regarded as a leading cause of global warming and environmental problems. An efficient method to capture CO2 from flue gases is oxy-fuel combustion. CO2 compression and purification unit (CO2CPU) is a promising process to capture CO2 from oxy-fuel combustion flue gases. However, the widespread implementation of this method is encountered with different techno-economical and legal challenges. The present study aims to review the principles and latest advances of CO2CPU process as well as the challenges this process may encounter in the future. The CO2CPU system is introduced and the latest research on the optimization and dynamic investigation of this process are reviewed. In addition, relevant standards and specifications of CO2 product as well as the effect of impurity are collected. Finally, a summary of the future challenges and research directions is presented.

Review on principles, recent progress, and future challenges for oxy-fuel combustion CO2 capture using compression and purification unit

In this paper, the combustion reaction kinetics of pyrolysis char of low-rank coal is studied by thermal analysis technology. For the combustion process of the char at different heating rates, the reaction kinetic parameters were calculated by three common mode-free methods (FWO method, KAS method and Starink method); the reaction model was determined by Malek method and Popescu method. Research shows that activation energy Eα of char combustion calculated by the three methods was 110.66–70.31 kJ mol−1, 104.35–59.60 kJ mol−1 and 104.34–59.99 kJ mol−1, respectively, and the activation energy decreased with increasing conversion rates. There is a compensation effect between the activation energy and pre-exponential factor of char combustion. Results of the kinetic analysis by Malek method and Popescu method both indicated that the Avrami–Erofeev equation (n = 3/2) (f(α) = 3/2(1 − α)[−ln(1 − α)]1/3) controlled by nucleation and nuclei growth models is the most probable reaction model of char combustion.

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Non-isothermal TGA study on the combustion reaction kinetics and mechanism of low-rank coal char

Experimental study on oxy-fuel combustion of heavy oil

A three-component particle-dynamics anemometer was used to measure the characteristics of two-phase gas-particle flows in a primary air nozzle using a gas/particle two-phase test facility. The jet trajectory of primary air velocities, Reynolds stress and particle concentration profiles were obtained. Based on this, the advantages and disadvantages of increasing the offset angle were analyzed to optimize performance. The results show that gas-particle slippage is not noticeable in the furnace, even though the mid-secondary air offset angle changes. Within the jet's free developing zone, the location of the peak concentration does not change with the mid-secondary air offset angles. Properly enlarging the offset angle of mid-secondary air nozzles will delay the mixing of the secondary air into the primary-air-and-coal mixture and realize horizontal-staged combustion in a furnace. It also can enhance the stability of airflow and form a better blended jet tail, meanwhile reducing the vortex at the back-fire side and avoiding a short circuiting of the airflow. It is favorable for increasing combustion efficiency and preventing slagging and high-temperature corrosion.

/pdf/influence-of-offset-angle-of-mid-secondary-air-nozzles-on-5slll5armj.pdf

Yingjie Hu

Papers

Non-isothermal TGA study on the combustion reaction kinetics and mechanism of low-rank coal char

Experimental investigation on ignition and burnout characteristics of semi-coke and bituminous coal blends

Experimental study on oxy-fuel combustion of heavy oil

Influence of offset angle of mid-secondary air nozzles on gas-particle flow characteristics in a furnace

Study of adsorption characteristics of calcium-based sorbents with SO3