Journal of Advanced Chemical Engineering

Hydrothermal carbonisation of poultry litter: Effects of initial pH on yields and chemical properties of hydrochars

2^nd International Conference on Advances in Chemical Engineering and Technology

November 16-17, 2017 | Paris, France

Bashir M. Ghanim, Witold Kwapinski and James J. Leahy

University of Limerick, Ireland

Posters & Accepted Abstracts: J Adv Chem Eng

Abstract:

Statement of the Problem: Poultry litter (PL) has been described as a complex mixture of alkyl moieties, sugars, aromatic systems, and acidic functionalities. Notwithstanding, the advantages of PL for increasing soil fertility, there are environmental concerns about its over application on agricultural sites which may result in human and animal health risks. Disposal technology for biowaste has clearly indicated that thermochemical conversion processes have the capability to covert animal by-products into combustible gases, bio-oils and solid products. Methodology & Theoretical Orientation: Unlike pyrolysis, gasification or combustion which require relatively dry feedstocks, hydrothermal carbonisation (HTC) typically is performed in water at moderate temperatures between 180 and 260 ºC and with residence times from 5 min to several hours under self-generated pressures above 1 MPa. In this study, HTC of PL was carried out at 250 °C for 2 h and at various initial pH using acetic acid or sulfuric acid to evaluate the impact of initial pH on the yields and properties of HC. Findings: The results indicated that undertaking HTC in the presence of acids (CH3COOH, H2SO4) significantly affects the yields and properties of HC. The C content and HHV of the HC increased with decreasing initial pH. In the presence of H2SO4, the hydrochar yield (HY) increased while the ash content was significantly reduced. The lowest ash content and the highest HY were measured in the HC produced from the suspension with an initial pH of 2 using H2SO4. Conclusion & Significance: The results also showed that the type of acids, organic or mineral, was important in terms of their effects on the yields and composition of HC. In the presence of acetic acid, the ash recovery decreased while carbon and energy recoveries relatively were constant. However, at high sulfuric acid concentration, energy, carbon and ash recoveries increased.