Steam gasification of pelletized hydrothermally pre-treated empty fruit bunch

Abstract

Empty fruit bunch (EFB) is a potentially new and renewable feedstock for gasification process to produce synthesis gas. Unfortunately, it has a low bulk density, high moisture content, and high ash content. So a pretreatment is needed for its utilization as a solid fuel. By using hydrothermal treatment (HT), the characteristic of EFB can be improved such as decreased ash content, easily dried, size reduction and subsequent pelletization. The hydrothermal treatment was conducted at 200°C and 60min. The solid product of HT was then pressed with a pressure up to 500 bar to get pellets with a diameter of about 1.0cm and a thickness of about 0.5cm. Experiments on steam gasification of HT-EFB pellet were carried out in a tubular reactor at a temperature of around 700°C. Before gasification, the pellets were heated up to 400°C to let the EFB undergo pyrolysis. Steam with a flow rate of 30g/h was introduced when bed temperature achieved 700°C. Nitrogen was used as an internal standard and was introduced at a rate of 100mL/min. After normalization excluding N 2 , the composition of synthesis gas obtained from gasification was more or less as follows: 65%-mol H 2 , 25%-mol CO and 10%-mol CO 2 . The composition of synthesis gas was naturally depended on the gasification temperature and the ratio of steam to pellets. Surprisingly, the form and size of the residue after the gasification process was still similar to pellets, but very porous.