Energy characteristics of the char obtained by two steps pyrolysis of chicken manure

Abstract

The thermal treatment of chicken manure is an ecological alternative of neutralizing this kind of waste with energy recovery. In this regard, a two-stage pyrolysis process was chosen, the first stage having the purpose of preheating and moisture elimination. The drying process up to the starting point of volatile matter release, about 200-250 C was taken into consideration. As a result of the moisture elimination in the first step of the pyrolysis process, a gas fuel riched in CO, CH4, H2 will be obtained. The experimental determinations consisted in the proximate and ultimate analysis of the initial residue and tests of the pyrolysis process in a pilot plant that allows the pyrolysis of a quantity of waste in range of 40-200g. A sample of a 140 g was subjected to the pyrolysis process at 500 C and the char (an organic, solid, consistent and odourless product) was obtained. The carbon (C), nitrogen (N), hydrogen (H) and sulphur (S) contents of the final product of pyrolysis were determined by a Costech 4120 Elemental Analyser that allows us to calculate the Lower Heating Value (LHV) of the char. For the evaluation of the energy potential, a theoretical balance of the energy consumption in the process of pyrolysis and the energy developed by combustion of the char, has been made. This theoretical balance was verified by determining the energy developed by combustion of char based on the composition determined in the laboratory. The laboratory results confirmed the existence of an energy potential of the pyrolysis product, which offers a technological alternative.