Upgrading Hydrothermal Carbonization (HTC) Hydrochar from Sewage Sludge

Eunhye Song, Seyong Park and Ho Kim
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Eunhye Song: Bio resource center, Institute for Advanced Engineering, Gyeonggi-do 17180, Korea
Seyong Park: Bio resource center, Institute for Advanced Engineering, Gyeonggi-do 17180, Korea
Ho Kim: Bio resource center, Institute for Advanced Engineering, Gyeonggi-do 17180, Korea

Energies, 2019, vol. 12, issue 12, 1-9

Abstract: As a treatment method of sewage sludge, the hydrothermal carbonization (HTC) process was adopted in this work. HTC has a great advantage considering the economic efficiency of its process operation due to its reduced energy consumption and production of solid fuel upgraded through the increased fixed carbon and heating value. The ash of sewage sludge, however, contains up to 52.55% phosphate, which degrades the efficiency of the thermochemical conversion process such as pyrolysis, combustion, and gasification by causing slagging. In this study, three kinds of organic acids, i.e., oxalic, tartaric, and citric acid, were selected to eliminate phosphorus from hydrochars produced through the HTC of sewage sludge. The efficiency of the phosphorus removal and the properties of the corresponding HTC hydrochars were analyzed by adding 20 mmoles of organic acids per 1 g of phosphorus in the HTC sample. In addition, the phosphorus reduction effect and the applicability to an upgrading process were verified. Oxalic acid was selected as the most appropriate organic acid considering the economic efficiency of its process operation. Furthermore, the optimal conditions were selected by analyzing the efficiency of the phosphorus elimination and the characteristic property of the HTC hydrochars with the weight fraction of oxalic acid.

Keywords: sewage sludge; hydrothermal carbonization; hydrochar; phosphate elimination; upgrading of hydrochar (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (7)

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