Production of hydrogen from polyoxymethylene in a binary fluidized bed

Two types of binary fluidized beds were constructed using sand and cenospheres. The first type consisted of sand and raw cenospheres, while the second type used sand and modified cenospheres. The pyrolysis of polyoxymethylene was studied at temperatures of 370, 400, 430, 460, 490, 540, and 590 °C. The products of polyoxymethylene pyrolysis were monitored using high-resolution infrared spectroscopy (1 cm−1). The chemical composition of complex gas mixtures was determined using a proprietary method of IR spectrum deconvolution. The presence of H2 in the outlet gases was confirmed chromatographically using a Molsieve 5 A column and a helium discharge detector dedicated to H2 detection. The process conditions for the pyrolysis of polyoxymethylene leading to the production of gas containing high volumetric shares of H2 were determined (e.g. 38%vol H2, binary fluidized bed made out of sand and raw cenospheres, 590 °C, 29%vol H2, binary fluidized bed made out of sand and modified-cenospheres, 370 °C). Additionally, the possibility of decomposing POM to recover the monomer (fluidized bed made out of sand and cenospheres, 370 °C); was demonstrated; or to obtain gas with a high H2/CO molar ratio of 2.3–2.8 (fluidized bed made out of sand and modified-cenospheres, 370-590 °C). An energy balance of the processes occurring in the reactor was conducted. The possibility of the reactor's autothermal operation was demonstrated, thanks to the combustion of by-products.