Pre-treatment technologies, and their effect on international bioenergy supply chain logistics. Techno-economic evaluation of torrefaction, fast pyrolysis and pelletisation.

Pollutants from the combustion of solid biomass fuels

Gasification is one of the promising technologies to convert biomass to gaseous fuels for distributed power generation. However, the commercial exploitation of biomass energy suffers from a number of logistics and technological challenges. In this review, the barriers in each of the steps from the collection of biomass to electricity generation are highlighted. The effects of parameters in supply chain management, pretreatment and conversion of biomass to gas, and cleaning and utilization of gas for power generation are discussed. Based on the studies, until recently, the gasification of biomass and gas cleaning are the most challenging part. For electricity generation, either using engine or gas turbine requires a stringent specification of gas composition and tar concentration in the product gas. Different types of updraft and downdraft gasifiers have been developed for gasification and a number of physical and catalytic tar separation methods have been investigated. However, the most efficient and popular one is yet to be developed for commercial purpose. In fact, the efficient gasification and gas cleaning methods can produce highly burnable gas with less tar content, so as to reduce the total consumption of biomass for a desired quantity of electricity generation. According to the recent report, an advanced gasification method with efficient tar cleaning can significantly reduce the biomass consumption, and thus the logistics and biomass pretreatment problems can be ultimately reduced.

Barriers of commercial power generation using biomass gasification gas: A review

An engineering economic analysis of a biomass pelleting process was performed for conditions in North America.
The pelletization of biomass consists of a series of unit operations: drying, size reduction, densifying, cooling, screening, and
warehousing. Capital and operating cost of the pelleting plant was estimated at several plant capacities. Pellet production
cost for a base case plant capacity of 6 t/h was about $51/t of pellets. Raw material cost was the largest cost element of the
total pellet production cost followed by personnel cost, drying cost, and pelleting mill cost. An increase in raw material cost
substantially increased the pellet production cost. Pellet plants with a capacity of more than 10 t/h decreased the costs to
roughly $40/t of pellets. Five different burner fuels – wet sawdust, dry sawdust, biomass pellets, natural gas, and coal were
tested for their effect on the cost of pellet production. Wet sawdust and coal, the cheapest burner fuels, produced the lowest
pellet production cost. The environmental impacts due to the potential emissions of these fuels during the combustion process
require further investigation.

Economics of producing fuel pellets from biomass

A detailed thermo-economic model considering different technological alternatives for thermochemical production of Synthetic Natural Gas (SNG) from lignocellulosic biomass is presented. First, candidate technology for processes based on biomass gasification and subsequent methanation is discussed and assembled in a general superstructure. Both energetic and economic models for biomass drying with air or steam, thermal pretreatment by torrefaction or pyrolysis, indirectly and directly heated gasification, methane synthesis and carbon dioxide removal by physical absorption, pressure swing adsorption and polymeric membranes are then developed. Performance computations for the different process steps and some exemplary technology scenarios of integrated plants are carried out, and overall energy and exergy efficiencies in the range of 69-76% and 63-69%, respectively, are assessed. For these scenarios, the production cost of SNG including the investment depreciation is estimated to 76-107 EUR/MWh SNG for a plant capacity of 20 MWth biomass, whereas 59-97 EUR/MWh SNG might be reached at scales of 150 MWth biomass and above. Based on this work, a future thermo-economic optimisation will allow for determining the most promising options for the polygeneration of fuel, power and heat.

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Thermo-economic process model for thermochemical production of Synthetic Natural Gas (SNG) from lignocellulosic biomass

Industrial Processes for Biomass Drying and Theri Effects on the Quality Properties of Wood Pellets

Industrial processes for biomass drying and their effects on the quality properties of wood pellets

The effects of kraft lignin additives on wood fuel pellet quality, energy use and shelf life

Presently, most fuel pellets are made from sawdust or shavings. In Sweden, these materials are used to the maximum extent. As the demand for pellets increases, the supply of sawdust will be insufficient and other raw materials or mixes of raw materials will be used. This work investigates sawdust mixed with rapeseed cake. The latter is a residual product from the production of chemically unmodified oil refined from cold-pressed rape oil. At the Department of Energy, Environmental and Building Technology at Karlstad University, Sweden, a complete pilot-scale pellet production unit is located. The pellets are produced and tested for mechanical durability, length, bulk density and moisture content according to the Swedish Standard for pellets. During production, the load current, the die pressure and the die temperature were measured along with other parameters. The main purpose was to examine how the mixture of rapeseed cake and pine sawdust affected the energy consumption of the pelletising machine and mechanical durability of mixed fuel pellets. The results show that the energy consumption decreased and the amount of fines increased with increasing rapeseed cake in the wood fuel pellets. These results indicate that we must compromise between a decrease in the use of energy and a decrease in durability.

Energy Efficient Pilot-Scale Production of Wood Fuel Pellets made from a Raw Material Mix Including Sawdust and Rapeseed Cake

Food waste is a significant problem for environmental, economic and food security reasons. The retailer, food service and consumers have been recognised as the parts of the food supply chain where ...

Waste of fresh fruit and vegetables at retailers in Sweden : Measuring and calculation of mass, economic cost and climate impact

In this study, we pelletized four different pure polysaccharides represented cellulose - Avicel, hemicelluloses - locus bean gum mannan and beech xylan and other polysaccharides - apple pectin, and ...

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Jonas Berghel

Papers

Industrial processes for biomass drying and their effects on the quality properties of wood pellets

The effects of kraft lignin additives on wood fuel pellet quality, energy use and shelf life

Energy Efficient Pilot-Scale Production of Wood Fuel Pellets made from a Raw Material Mix Including Sawdust and Rapeseed Cake

Waste of fresh fruit and vegetables at retailers in Sweden : Measuring and calculation of mass, economic cost and climate impact

Effects of moisture content during densification of biomass pellets, focusing on polysaccharide substances