The pyrolysis and combustion of polyoxymethylene in a fluidised bed with the possibility of incorporating CO2

The recycling of polyoxymethylene (POM) was performed in a fluidised bed which was formed from cenospheres (hollow, spherical particles). Air, N-2 and CO2 were used as the fluidising agents. The composition of the process products in the flue gases as a function of fluidised bed temperature is shown and discussed for each fluidising gas. A flue gases FTIR analysis together with the spectra deconvolution of multicomponent gaseous samples were used to conduct instant quantitative monitoring of the products of POM thermal degradation. At 400 degrees C, in atmospheres of either air or CO2, the process of POM thermal recycling was performed for the purpose of monomer recovery and obtained a near 90% efficiency of formaldehyde formation. At temperatures above 600 degrees C, it was found that the use of air or N-2 leads to the recovery of energy or gas rich in CO, respectively. The CO-rich gas was obtained during the pyrolysis of POM when CO2 constituted the fluidising agent. The amount of CO in the flue gas was almost twice as large as the amount of carbon introduced into the process in the polymer material. This means that carbon was converted to CO from the fluidising medium, thus recycling of POM to the CO-rich feedstock was obtained with a negative CO2 emission. The main advantage of the POM pyrolysis in the nitrogen atmosphere was monomer recovery.