Jim Lim

Sulfation and reactivation characteristics of nine limestones

The sulfation and steam hydration reactivation characteristics of nine limestones were evaluated based on laboratory sulfation and hydration tests and scanning electron microscope analyses. The calcium utilization and the sulfation pattern of the limestones were found to depend on the morphology and microstructure of the calcined limestones. Three sulfation patterns were observed in the limestones: unreacted core, uniformly sulfated and network. The steam hydration behavior of the sulfated limestones was dependent on the sulfation pattern. Unreacted core particles appeared to be easier to reactivate, thereby giving higher overall calcium utilization, compared to network-sulfated particles. Uniformly sulfated particles did not react upon hydration and could not be reactivated with steam at 250 or 450°C.

Crystallization and fracture: formation of product layers in sulfation of calcined limestone

Abstract Sulfation experiments were carried out and product layers were characterized to investigate the reaction kinetics and to test a Crystallization and Fracture (CF) model describing the mechanism of formation of product layers. Sintered samples of calcined limestone were sulfated in a quartz reactor for short and extended times in order to obtain initial and fully developed product layers. The product layers were characterized by means of Scanning Electron Microscopy (SEM) visualization and measurements of BET surface area and pore size distribution. At lower temperatures, the sulfation reaction ceased after a relatively short time, whereas at higher temperatures, the reaction continued at an approximately constant rate for as long as 30 h. The reaction product was formed by crystallization. The product “layer” formed in the early stages of the reaction was not a true layer, but isolated nuclei and crystals. The “continuous” product layer formed in the later stages of the reaction was found to be a monolayer of individual crystals with pores of size 20–30 A along the boundaries. The product layer was more porous when developed from larger stable nuclei formed during the initial reaction at higher temperatures and lower SO 2 concentrations. These observations support the mechanism described by the CF model.

An economical and market analysis of Canadian wood pellets.

This study systematically examined the current and future wood pellet market, estimated the cost of Canadian torrefied pellets, and compared the torrefied pellets with the conventional pellets on the basis of literature and industrial data. The results showed that the wood pellet industry has been gaining significant momentum due to the European bioenergy incentives and the rising oil and natural gas prices. With the new bioenergy incentives in USA, the future pellets market may shift to North America, and Canada can potentially become the largest pellet production centre, supported by the abundant wood residues and mountain pine beetle (MPB)-infested trees.

Physical characterization of wet and dry wheat straw and switchgrass – bulk and specific density

Bulk density of biomass is a major factor in determining the cost and logistics requirements of handling and moving biomass from farm to biorefinery. Bulk density is a strong function of size and shape and individual particle density. In this research we study experimentally the effect of particle length, moisture content, and particle density on bulk density of wheat straw and switchgrass. Wheat straw and switchgrass stems were cut to exact nominal lengths of 6, 12, 25, and 50 mm. The moisture contents of biomass samples were adjusted upward from an original 8% to 20, 40, and 60%. Three particle densities were measured assuming two structural geometries for the stems; i.e a hollow cylinder and a solid cylinder. The particle densities were measured using a gas pycnometer at a gas

ECONOMICS OF PELLET PRODUCTION FOR EXPORT MARKET

Due to its renewable, clean-burning and cost-stable for home heating, wood pellet is gaining popularity day by day throughout North America. The use of pellets in co-firing with coal enhanced its utilization suddenly in Europe. As a result, some countries in Europe are planning to import wood pellets from Africa, America or neighboring European countries due to the shortage of wood in long term basis. This study focuses on the pellet production in Canada and its export to Sweden or the Netherlands. The transport and supply logistics were analyzed. The results showed that the total production cost of pellets was US

Review and analysis of performance and productivity of size reduction equipment for fibrous materials

46.8 per metric tonne and among which 4.5 US

Application of a model to simulate the wetting and drying processes of woody biomass in the field

/tonne was the capital investment. The transport and supply logistics cost estimated as US

A dual-scale lattice gas automata model for gas-solid two-phase flow in bubbling fluidized beds

96.1 or 89.1 per tonne for exporting to Sweden and the Netherlands, respectively. The internal rates of return for the two cases were estimated as 24 and 37%, respectively, with a plant life of 10 years and the payout periods of 4 and 3 years, respectively.

Low Air Flow Permeability Of Wood Pellets

Size reduction is an important pre--processing of biomass using as an energy source. The end technology and final use of ground biomass depends on the biomass specie, physical and chemical properties, organic and inorganic contaminants, and geometry of the ground particles. The purpose of this study is to review size reduction equipment on basis of selection criteria, operation, productivity, performance, energy requirement, input feedstock, particle size distribution of ground biomass, and their utilization. This review and analysis shows that there is a great potential of tub grinding as a means of preparing crop and forest residues for Bioenergy purposes. The review also reveals the correlation among the grinding rate, screen size, tub speed, particle size distribution and specific energy requirement. This study shows that an amount of US

Determination of Thermal Conductivity of Wood Pellets Using Line Heat Source Method

3.01/ton is necessary to process agricultural residues with a tub grinder of capacity 70 ton/hr.