The conditions of the hydrothermal carbonization process to produce biochar from coffee husk will be optimized for maximum yield. Besides, response surface methodology (RSM) and central composite face-centered (CCF) method will be used in designing experiments. Also, the optimal value of factors such as temperature, time and biomass: water ratio which can provide a maximum yield of biochar will be worked out using Modde . | Journal of Science and Technology 54 (4B) (2016) 138-145 OPTIMIZING THE PROCESS OF TRANSFORMING COFFEE HUSKS INTO BIOCHAR BY MEANS OF HYDROTHERMAL CARBONIZATION Tran Thi Hien1, *, Nguyen The Vu2, Phan Thi Que Phuong3, 4, Pham Huu Thien3, 4, Nguyen Dinh Thanh4, Phan Dinh Tuan5 1 Industrial University of Ho Chi Minh City, Go Vap District, Ho Chi Minh City. 2 Ho Chi Minh Vocational College of Technology, District 9, Ho Chi Minh City. 3 4 5 Dong Nai University of Technology, Bien Hoa City, Dong Nai province. Institute of Applied Materials Science, Vietnamese Academy of Science and Technology, District 1, Ho Chi Minh City. University of Natural Resources and Environment, Tan Binh District, Ho Chi Minh City. * Email: tranhien86@ Received: 15 August 2016; Accepted for publication: 10 November 2016 ABSTRACT The conditions of the hydrothermal carbonization process to produce biochar from coffee husk will be optimized for maximum yield. Besides, response surface methodology (RSM) and central composite face-centered (CCF) method will be used in designing experiments. Also, the optimal value of factors such as temperature, time and biomass: water ratio which can provide a maximum yield of biochar will be worked out using Modde . As a result, the optimal conditions for maximum yield of biochar was obtained as temperature of 180 oC, h and biomass: water ratio of 15 %. It can also be concluded that temperature has greater impact on the transformation of biochar than time and biomass: water ratio. Keyword: optimization, coffee husks, agricultural waste, hydrothermal carbonization, biochar. 1. INTRODUCTION Hydrothermal carbonization method (HTC) is a promising method for transforming agricultural waste products with high yield [1]. It has the capability of decomposing biomass feedstock sources with high humidity (up to 80 %) at low temperature of about 160 – 270 °C, solid component (biochar) and the liquid (mixture containing organic compounds). HTC .
