|Flora, Joseph R.v. - University Of South Carolina|
|Bae, Sunyoung - Seoul Women'S University|
|Libra, Judy - Leibniz Institute|
|Berge, Nicole - University Of South Carolina|
|Alvarez-murillo, Andres - University Of Extremadura|
Submitted to: ACS Sustainable Chemistry & Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2017
Publication Date: 6/30/2017
Citation: Ro, K.S., Flora, J., Bae, S., Libra, J.A., Berge, N., Alvarez-Murillo, A. 2017. Properties of animal-manure based hydrochars and predictions using published models. ACS Sustainable Chemistry & Engineering. 5:7317-7324.
Interpretive Summary: Hydrochar produced from hydrothermal carbonization (HTC) of animal manure is a carbonaceous solid. It can be used as a cooking fuel, as well as a soil amendment to improve soil quality and reduce nutrient leaching. It can also be used to remove environmental pollutants such as heavy metals, pharmaceuticals and personal care products (PPCPs) from water. Feedstock characteristics and HTC process determine the hydrochar properties. In this research, we investigated the effectiveness of predictive statistical models published in the literature in predicting animal-manure based hydrochar properties based on raw animal manure characteristics and HTC process conditions. All three models reasonably predicted the hydrochar yields and carbon contents. However, prediction of energy contents was not satisfactory. It is important to develop better predictive models for energy contents of hydrochar for energy application.
Technical Abstract: In order to fully utilize hydrothermal carbonization (HTC) to produce value-added hydrochars from animal manures, it is important to understand how process conditions (e.g., temperature, reaction time, solids concentration) influence product characteristics. The effect of process conditions on the extent of carbonization, solid yield, energy density and combustion characteristics of the hydrochars, as well as the fate of carbon (C) and nitrogen (N) in the three phase process was investigated for swine solids and poultry litter. While hydrothermal treatment increased the percentage of fixed carbon in the solids compared to the original feedstock, increasing reaction time fivefold did not increase the percentage of fixed carbon in the hydrochars. Increasing temperature had an inverse effect on solid yield and to a lesser extent on energy content. Three different published statistical models in the literature were evaluated for their ability to predict hydrochar properties based on feedstock properties and process parameters. All three models reasonably predicted the yields and C contents; however, prediction of energy contents of animal manure hydrochars was not satisfactory. It is important to develop better predictive models for energy contents of hydrochar for energy application.