Development and evaluation of a densification system for rice straw | |
| Author | Rahaman, Sheikh Aminur |
| Call Number | AIT Thesis no.ET-15-03 |
| Subject(s) | Biomass energy Straw as fuel |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Energy |
| Publisher | Asian Institute of Technology |
| Abstract | Densification is the primary solution for low bulk density biomass resources which reduces transportation and storage cost and energy consumption. Similarly co-densification of low and high grade biomass improves the characteristics of densified products and increases the utilization of low grade biomass fuel. Hence, this study focused on the development of laboratory scale cold densification system which is able to densify any type of biomass materials with and without pre-treatment, and allows to vary operational parameters in briquette preparation step are briquette outer diameter, inner hole to outer diameter ratio, moisture content, applied pressure (maximum 79.06MPa), binder ratio and briquette height. Rice straw, highly abundant agricultural field residue biomass resource in Asia as 90.51% rice is cultivated here which has high residue-to-production ratio, was used as raw material to prepare briquettes in absence and presence of binding material (sawdust). The selected operational parameters were four different particle sizes, chopped by hammer mill (2.5, 6.5, and 9.5mm) and knife cutting mill (knife milled, 10-150 mm), two mold inner diameter (70 and 51 mm), six different pressures (13.8-48.3MPa) and three binder ratios (3:1, 1:1 and 1:3, rice straw : sawdust, weight basis). It was observed that briquettes of 2.5 mm and knife milled particles showed the best performance in terms of initial density, relaxed density, density ratio, compaction ratio and shatter index. Most interestingly although knife milled particles are larger compared to hammer milled particles, shatter index is way too high compared to briquettes of hammer milled particles even at lower pressure. Reduction of mold inner diameter significantly improved physical characteristics of briquettes and reduces pressure demand. Briquettes stable density (prepared in SM) of 619.3 kg/m3 and 497.83 kg/m3 was found at 48.3MPa for 2.5 mm and knife milled particles respectively which is comparable to density of briquettes prepared through hot densification process. Percentage of energy consumption, which is stored in 1 kg or rice straw, in briquette preparation was 1.28%, 2.04%, 2.32%, and 3.18% for knife milled, 9.5, 6.5, and 2.5mm rice straw particles, respectively. In co-densification of rice straw with sawdust significantly improved briquettes initial and relaxed density, shatter index and calorific value, decreased axial and volumetric expansion, and most importantly reduced briquettes ash content from 13.61% to 10.3% 6.93% and 3.86% at 3:1, 1:1 and 1:3 binder ratios respectively. Moreover, using sawdust as binding material pressure requirement also can be reduced for cold densification of rice straw biomass. |
| Year | 2015 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Energy Technology (ET) |
| Chairperson(s) | Salam, Abdul P.; |
| Examination Committee(s) | Kumar, Sivanappan;N. T. Kim Oanh; |
| Scholarship Donor(s) | Thailand (HM Queen); |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2015 |