Dalai: Investigation and Demonstration of Close Coupled Gasification and Combustion of Raw Glycerin and Canola Hull Fiber Fuel Pellets/Briquettes
Date: March 2014
Term: n/a
Status: Completed
Researcher(s): Ajay K. Dalai, University of Saskatchewan, Saskatoon SK and Janusz A. Kozinski, York University, Toronto ON
SaskCanola Investment: n/a
Total Project Cost: n/a
Funding Partners: ADF, NSERC
Project Summary
The demand for diversified, easily transported, carbon-neutral energy from biomass, including 'waste' biomasses, such as sawdust, crop residues and other industrial wastes, is increasing. Researchers conducted a three-phase study in 2014 to investigate the use of canola meal as a potential energy source. Canola meals can be used in the form of either direct canola meal waste or as pellets made from canola meal, canola meal with crude glycerol using various techniques. The results of the study conclude that canola meal pellets can provide an alternative for biofuel production from waste biomass feedstocks in the form of moisture-resistant quality fuel pellets.
The demand for diversified, easily transported, carbon-neutral energy from biomass, including 'waste' biomasses, such as sawdust, crop residues and other industrial wastes, is increasing. In this study, biomass material for renewable energy, such as canola meal, was widely explored as an energy source, which has a sustainable supply in Canada and safe to use. Canola meal can be used for energy production in the form of either direct canola meal waste or as pellets made from canola meal, canola meal with crude glycerol using various techniques. Researchers from the University of Saskatchewan and the York University conducted on a three-phase study in 2014 to investigate the use of canola meal as a potential energy source.
Phase 1: Pelletization of canola meal using crude glycerol as binding agents and steam gasification of canola meal after protein extraction for synthesis gas production in a fixed-bed reactor.
In Phase 1, original canola meal (mixture of canola meal and canola hull fibers) and crude glycerol were characterized for their physical and chemical properties. The ultimate analysis (CHNS), ash content, moisture content and ash elemental composition were performed for both the precursors. Pelletization operating conditions (temperature, applied pressure, and relaxation time) were examined for their effects on the thermal and mechanical properties of fuel pellets made from canola meal using crude glycerol binder, as a by-product of biodiesel industry. In the further study, protein extracted canola meal (deproteinated canola meal) was used to study the production of syngas from the gasification process in a fixed bed reactor system. This work showed that protein can be effectively removed from canola meal and this feed can be used as a feedstock for syngas production using gasification process.
The study found the heating value of canola meal to be ~20 MJ/kg, whereas for pellets prepared with 5 and 10 %(w/w) of crude glycerol ranged from 21.5-22.0 MJ/kg. The results showed that crude glycerol was an effective binding agent in the concentration range of 5-10 % (weight/weight or w/w). Pellets made with 5 % (w/w) crude glycerol demonstrated the best handling characteristics with a survival rate of ~ 92%. The heating value of pellets made using 5 and 10 % (w/w) of glycerol increased slightly from the original canola meal pellet. Canola meal after protein extraction can be effectively used as a feedstock for steam gasification to produce synthesis gas (syngas). The effects of gasification temperature and equivalence ratio (ER) on the products were investigated in a 2-stage reactor set-up in this research. The gas produced under all operating conditions had a lower heating value (LHV) of between 9-12 MJ/Nm3, making it suitable for methanol production. The study also showed that the use of dolomite as a catalyst for tar cracking reduced tar formation by 50% and the total syngas production was observed as high as 1.14 Nm3/kg.
Phase 2: Gasification of canola meal and factors affecting gasification process.
Phase 2 involved the non-catalytic gasification of canola meal for the production of syngas in lab scale fixed bed gasifier and pilot scale fluidized bed gasifier. Various experiments were conducted to study the effects of gasification operating conditions on product gas composition, H2/CO ratio, gas and syngas yield, heating value and carbon efficiency. Experiments were performed at gasification temperature in the range of 650-850C and equivalence ratio in the range of 0.2- 0.4, using steam, oxygen (O2) and carbon dioxide (CO2) as gasifying agents.
The results from the pilot scale gasification system indicated that steam gasification produced the higher syngas yield and total percentage of H2 and CO in the synthesis gas. CO2 gasification promoted maximum gas yield (82.8 mol/kg biomass) and O2 gasification gave maximum carbon efficiency (65.5%), compared to steam (44.6%) and CO2 (41.3%).
Phase 3: Canola meal moisture-resistant fuel pellets: Study on variables, effects of additives on the pellet quality and compression characteristics.
Phase 3 focused on pelletization of canola meal biomass to increase bulk density, reduce transportation and storage costs, and therefore provide better material feeding with less dust formation. The study investigated the effects of additives (including binder, lubricant and moisture) along with effects of applied pressure and temperature on the quality of pellets. The relationship between applied pressure for pelletization and pellet density was studied using Kawakita and Ludde model. The effects of coating agent on pellet durability, hardness and moisture uptake were studied to produce moisture-resistant pellets.
The study results showed that pelletization temperature and applied pressure significantly affected pellet quality. Optimized pellets with 99 % durability and 189 N hardness were produced at an applied load of 3500 N and a temperature of 90C with the 5% (w/w) binder, 2% (w/w) lubricant and 12 % (w/w) moisture content. The study show that canola meal particles undergo extensive rearrangement followed by fragmentation and deformation during the compression process at temperatures >70oC. Coated pellets exposed to the ambient temperature could sustain durability (~98%) and hardness (~168 N) up to eight weeks without any moisture uptake, compared to uncoated control pellets that lose its durability (~48%) and hardness (~117 N) due to moisture uptake.
The pellets were gasified in a fixed bed reactor and an assessment of the effects of different gasifying agents (including steam, O2 and CO2) on the quantity and quality of gas product, bio-oil, and bio-char was performed. This assessment showed that canola meal pellets can be used as a substitute for other biomass solid fuels. The gas product produced using steam, O2 and CO2 gasifying agent was found to have LHV in the range of 40-50 MJ/m3.
Overall, the results of this three-phase study showed that by producing moisture-resistant canola meal pellets with reasonable fuel characteristics, pelletization of canola meal provides a promising alternative for the utilization of canola meal waste as an alternative source of renewable energy in Canada.
Scientific Publications
A. Tilay, R. Azargohar, R. Gerspacher, A. K. Dalai, J. A. Kozinski, “Gasification of canola meal and factors affecting gasification process”, Bioenergy Research Journal 7 (2014) 1131-1143.
A. Tilay, R. Azargohar, M. Drisdelle, A. K. Dalai, J. A. Kozinski, “Canola meal moisture-resistant fuel pellets: Study on the effects of process variables and additives on the pellet quality and compression characteristics”, Journal of Industrial Crops and Products 63 (2015) 337-348.