Ignition by Thermal Radiation of Polyethylene and Human Feces Combustible Wastes: Time and Temperature to Ignition

Abstract

Due to the growing energy demands of the world and the rapid depletion of fossil fuels, it is necessary to study new energy sources. The waste have a great potential to be tapped, as besides being a raw material abundant, their use helps in reducing the level of environmental pollution and curbing the volume of waste in cities. However, one should know well the combustion process these waste before using them as fuel. Thus, Ignition behavior of combustible wastes was studied in a built fixed bed reactor. To provide a controlled thermal radiation for the ignition instant, a radiative heat flux is generated by a metal surface called a cone heater calibrated to establish the radiative heat flux density provided by a thermal resistance of 2 kW. The heat flux was 25 to 30 kWm2 over the top surface of the fuels. To validate the process, experiments with charcoal were performed varying the diameter of particles and air flow. After this, the polyethylene and human feces were analyzed. Their effects were investigated on the ignition time.

Processes defining smouldering combustion: Integrated review and synthesis

“…Given that the processes that define the upper limits of radiative heating are material dependent, it is not possible to define bounds that apply in a universal manner. Nevertheless, the upper bounds for the ignition source for smouldering have been explored by several authors [28, 60,241,[248][249][250][251][252][253] mostly for polyurethane foams [241,252,253].…”

“…In addition, smouldering has been proposed for managing sewage sludge (in some cases termed biosolids), the dominant waste from industrial waste water treatment plants [56], and for recovering energy from pine bark waste [57]. Recently smouldering has been applied as an energy efficient destruction technique for human faeces [58][59][60][61]. This has led to the development of a continuous smouldering reactor that recovers and reuses the excess energy as part of an innovative, off-grid toilet designed to address the sanitation challenges of impoverished countries [62].…”

Energy recovery from human faeces via gasification: A thermodynamic equilibrium modelling approach

“…A few studies [19] , [3] that have simulated the thermochemical conversion of human faeces have explored technologies such as plasma gasification, hydrothermal carbonization, with processes differing from the described study approach. More so, the experimental studies by Ward et al [39] , Muspratt et al [26] , Afolabi et al [1] and Monhol and Martins [24] , [23] have exploited technologies such as pyrolysis, hydrothermal carbonization and combustion to investigate product recovery from human faeces, and not gasification.…”

Design and commissioning of a multi-mode prototype for thermochemical conversion of human faeces

“…Monhol and Martins [33] also reported the ignition temperature of dried human faeces at about 220 °C. Ignition was achieved by exposing the sample to radiative heat flux density of 25–30 kW/m 2 .…”