Effect of Nitrogen/Oxygen Substances on the Pyrolysis of Alkane-Rich Gases to Acetylene by Thermal Plasma

Abstract

Abstract:It is important to convert alkane-rich gases, such as coke oven gas, to value-added chemicals rather than direct emission or combustion. Abundant nitrogen/oxygen substances are present in the actual alkane-rich gases. However, the research about how they influence the conversion in the pyrolysis process is missing. In this work, a systematic investigation on the effect of various nitrogen/oxygen-containing substances, including N 2 , CO, and CO 2 ,on the pyrolysis of CH 4 to C 2 H 2 was performed by a self-made 50 kW rotating arc thermal plasma reactor, and the pyrolysis of a simulated coke oven gas as a model of alkane-rich mixing gas was conducted as well. It was found that the presence of N 2 and CO 2 was not conducive to the main reaction of alkane pyrolysis for C 2 H 2 , while CO, as a stable equilibrium product, had little effect on the cracking reaction. Consequently, it is suggested that a pretreatment process of removing N 2 and CO 2 should be present before pyrolysis. Both input power and feed rate had considerable effect on the pyrolysis of the simulated coke oven gas, and a C 2 H 2 selectivity of 91.2% and a yield of 68.3% could be obtained at an input power of 17.9 kW.

Non-Thermal Plasma Pyrolysis of Fuel Oil in the Liquid Phase

“…A distinction is made between thermal plasma (TP) and non-thermal plasma (NTP) according to particle energy and plasma temperature [24]. TP requires tens of kilowatts of power at a plasma temperature of ~10,000 • C, which helps increase the yield of gas phase products such as hydrogen, acetylene, and other gaseous hydrocarbons [25,26]. However, a significant portion of the input power for TP generation is lost through heating the system.…”

The Effect of Humidity on the Atomization Process and Structure of Nanopowder Designed for Extinguishment

“…An important role in this mechanism is performed by the presence of nitrogen, especially at temperatures >500 °C, both in the air (Zeldovich mechanism) and in the fuel (oxidation and reduction mechanisms) or as so-called fuel radicals according to the scheme in Figure 2. The contribution of nitrogen involves the activation of the oxygen radical O* [4][5][6]. On the other hand, for solid and liquid fuels, in the presence of oxygen and hydrogen, some intermediate gaseous compounds can be formed which undergo further oxidation and reduction reactions.…”

“…The presence of combustion reaction radicals is associated with the unusual properties of water, which is the only one in nature that exists in three states of aggregation An important role in this mechanism is performed by the presence of nitrogen, especially at temperatures >500 • C, both in the air (Zeldovich mechanism) and in the fuel (oxidation and reduction mechanisms) or as so-called fuel radicals according to the scheme in Figure 2. The contribution of nitrogen involves the activation of the oxygen radical O* [4][5][6]. Heat is required to initiate radicals and to sustain pyrolysis or fuel evaporation.…”