Comparative Analysis of Pelletized and Unpelletized Sunflower Husks Combustion Process in a Batch-Type Reactor.

This paper describes characteristics of the combustion of sunflower husk (SH), sunflower husk pellets (SHP), and, for comparison, hardwood pellets (HP). The experiments were carried out using a laboratory-scale combustion reactor. A proximate analysis showed that the material may constitute an alternative fuel, with a relatively high heating value (HHV) of 18 MJ/kg. For SHP, both the maximum combustion temperatures (TMAX = 1110 °C) and the kinetic parameters (temperature front velocity vt = 7.9 mm/min, combustion front velocity vc = 8 mm/min, mass loss rate vm = 14.7 g/min) of the process were very similar to those obtained for good-quality hardwood pellets (TMAX = 1090 °C, vt = 5.4 mm/min, vc = 5.2 mm/min, vm = 13.2 g/min) and generally very different form SH (TMAX = 840 °C, vt = 20.7 mm/min, vc = 19 mm/min, vm = 13.1 g/min). The analysis of ash from SH and SHP combustion showed that it has good physicochemical properties (ash melting point temperatures >1500 °C) and is safe for the environment. Furthermore, the research showed that the pelletization of SH transformed a difficult fuel into a high-quality substitute for hardwood pellets, giving a similar fuel consumption density (Fout = 0.083 kg/s·m2 for SHP and 0.077 kg/s·m2 for HP) and power output density (Pρ = MW/m2 for SHP and 1.5 MW/m2 for HP).

Carbonization of corncobs for the preparation of barbecue charcoal and combustion characteristics of corncob char.

The paper examines the process of carbonization of waste from corncobs at carbonization temperatures within a range of 300-700 °C in a laboratory-scale reactor. These studies are important because of reductions in wood resources for the preparation of barbecue charcoal due to environmental protection laws and legislative processes in many countries aimed at the protection of forest resources. The results presented here include the physical and chemical properties of char as a function of carbonization temperatures as well as the characteristics of the heating rate of a fixed bed of corncobs and within a single corncob particle. The combustion characteristics of the char were determined using thermogravimetric analysis. The results show that the volatile matter yield of the char decreased, whereas the fixed carbon yield and higher heating value (HHV) increased, along with higher carbonization temperatures. TGA analysis shows that the ignition and burnout temperature of the char increased, with a simultaneous decrease in the value of the S index, along with increased carbonization temperatures. The results show that carbonization temperatures of 500 °C and above meet the standards for the production of barbecue charcoal.

The influence of temperature on the physicochemical properties of products of pyrolysis of leather-tannery waste.

The present paper examines the pyrolysis of waste from leather tanneries at 300-500 °C. These studies are important because of difficulties in the utilisation of this type of waste as well as its energy potential as fuel. The pyrolysis of tannery waste and data from the relevant literature showed that thermal degradation can be explained using tanned collagen as a reference. Moreover, the experimental results indicated that this process is highly non-linear, due to various mechanisms of heat transport which cause temperature differences in a laboratory pyrolysis reactor. Thermogravimetric analysis has shown that the greater part of mass loss is observed between 80 and 500 °C and that the most significant mass release occurs at 325 °C. Moreover, the proportions of CO2 and CO decrease along with increasing temperatures. The paper presents characteristics of the composition of solid, liquid, and gaseous products of leather-waste pyrolysis at various temperatures. The maximum heating value of gaseous products at 500 °C was 9.54 MJ/Nm3. An increase from 300 to 500 °C results in the dominant position of condensation polymerisation; the maximum value of the liquid phase yield is reached at 400 °C (42%). HHV analysis of the resulting char showed a maximum value of 21.18 MJ/kg at 450 °C. The results of oxidised component analysis showed that the major oxidised component of char was chromium oxide (Cr2O3), with a content of approximately 8.5% at all pyrolysis temperatures.