Delta Research Corporation

Delta, Canada

Delta Research Corporation

Delta, Canada

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He X.,University of British Columbia | Lau A.K.,University of British Columbia | Sokhansanj S.,University of British Columbia | Sokhansanj S.,Oak Ridge National Laboratory | And 5 more authors.
Biomass and Bioenergy | Year: 2013

The objectives of this study were to investigate the effects of temperature and relative humidity on the sorption characteristics and the drying rate of woody biomass, and to develop a sorption isotherm model. Experiments using Trembling Aspen (. Populus tremuloides) as materials were conducted in a controlled environment chamber. Results showed that low temperature and high relative humidity of ambient air led to higher equilibrium moisture content (EMC) for both desorption and adsorption processes. At higher temperature, the EMC was reached over a shorter drying time indicating a higher sorption rate; relative humidity was also positively correlated with the adsorption rate. The Modified Oswin model that relates equilibrium relative humidity to temperature and EMC was found to provide the best fit to the experimental data. The trend of drying rate constant versus temperature followed the Arrhenius equation, and Page's model was appropriate for predicting the drying characteristics of Aspen. © 2013 Elsevier Ltd.


Yazdanpanah F.,University of British Columbia | Sokhansanj S.,University of British Columbia | Sokhansanj S.,Oak Ridge National Laboratory | Lim C.J.,University of British Columbia | And 4 more authors.
Biomass and Bioenergy | Year: 2014

Wood pellets emit gases such as CO, CO2 and CH4 during storage especially under high temperature conditions. This study investigates the stratification of the evolved gases in a sealed storage container of 1.2m diameter and 4.6m height. The data recorded include the concentration of off-gasses (CO2, CO and CH4), temperature and relative humidity profiles in vertical and horizontal directions. The results obtained clearly show high concentration of gases as well as fast depletion of oxygen. The emitted gases showed to have higher emission factor compared to work done with white wood pellets in small scale. Some stratification was observed for CO2 and CH4 over the first days of storage. However for CO the stratification was much clear and related to high uptake of CO by wood pellets over time. © 2014 Elsevier Ltd.


Yazdanpanah F.,University of British Columbia | Sokhansanj S.,University of British Columbia | Sokhansanj S.,Oak Ridge National Laboratory | Lau A.K.,University of British Columbia | And 4 more authors.
Biomass and Bioenergy | Year: 2011

Data on the resistance of wood pellets to airflow are required for the design and control of ventilation, cooling, and drying of bulk pellets. In this study, pressure drops versus airflows were measured for several sizes of cylindrical wood pellets. The pellet diameter was 6.4 mm; the length varied from 4 to 34 mm. Experimental airflow rates ranged from 0.014 to 0.8 m3s-1 m-2. The corresponding measured static pressures ranged from 2 to 2550 Pa m-1. Three predictive models of Shedd, Hukill-Ives, and Ergun that relate pressure drop to airflow in bulk granular materials were fitted to the data. The Ergun equation provided the best fit. The results obtained from this study are comparable to those reported by other researchers for biomass such as 28 mm long cut willow chips and 6.4 mm diameter alfalfa pellets. © 2011 Elsevier Ltd.


He X.,University of British Columbia | Lau A.K.,University of British Columbia | Sokhansanj S.,University of British Columbia | Sokhansanj S.,Oak Ridge National Laboratory | And 4 more authors.
Fuel | Year: 2012

Past published research on the storage of fresh woody biomass has rarely presented observations of gaseous emissions in combination with the related dry matter losses. The objectives of this study are to determine dry matter losses and gaseous emissions from stored logging residues. Lab-scale vessels were set up to study the concentration of off gases at 15°C and 35°C. Results showed that the maximum concentrations of CO 2, CO and CH 4 were 13.8%, 0.16%, and 0.15%, respectively over a period of 35 days. The oxygen level decreased to 0% at the end of storage. Volatile organic compounds (VOCs) were qualitatively detected by GC/MS technique. The major chemical compounds identified were alcohols, terpenes, aldehydes, acids, acetone, benzene, ethers and esters. The total VOC concentration reached 85 ppm at 35°C storage temperature at the end of the storage period. Dry matter loss ranged from 0.78% to 2.0% increasing with storage temperature. © 2012 Elsevier Ltd. All rights reserved.


Peng J.H.,University of British Columbia | Bi H.T.,University of British Columbia | Sokhansanj S.,University of British Columbia | Sokhansanj S.,Oak Ridge National Laboratory | And 2 more authors.
International Journal of Green Energy | Year: 2010

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.


Ghafghazi S.,University of British Columbia | Sowlati T.,University of British Columbia | Sokhansanj S.,University of British Columbia | Sokhansanj S.,Oak Ridge National Laboratory | And 2 more authors.
Applied Energy | Year: 2010

District energy systems, in which renewable energy sources may be utilized, are centralized systems to provide energy to residential and commercial buildings. The aim of this paper is to evaluate and rank energy sources available for a case of district heating system in Vancouver, Canada, based on multiple criteria and the view points of different stakeholders, and to show how communication would affect the ranking of alternatives. The available energy sources are natural gas, biomass (wood pellets), sewer heat, and geothermal heat. The evaluation criteria include GHG emissions, particulate matter emissions, maturity of technology, traffic load, and local source. In order to rank the energy options the PROMETHEE method is used. In this paper, two different scenarios were developed to indicate how the communication between the stakeholders would affect their preferences about criteria weights and would change the ranking of alternatives. The result of this study shows that without communication the best energy source for the considered district energy system is different for different stakeholders. While, addressing concerns through efficient communication would result in a general consensus. In this case, wood pellet is the best energy alternative for all the stakeholders. © 2009 Elsevier Ltd. All rights reserved.


Ghafghazi S.,University of British Columbia | Sowlati T.,University of British Columbia | Sokhansanj S.,University of British Columbia | Sokhansanj S.,Oak Ridge National Laboratory | Melin S.,Delta Research Corporation
International Journal of Energy Research | Year: 2010

With the increased interest in exploiting renewable energy sources for district heating applications, the economic comparison of viable options has been considered as an important step in making a sound decision. In this paper, the economic performance of several energy options for a district heating system in Vancouver, British Columbia, is studied. The considered district heating system includes a 10MW peaking/backup natural gas boiler to provide about 40% of the annual energy requirement and a 2.5MW base-load system. The energy options for the base-load system include: wood pellet, sewer heat, and geothermal heat. Present values of initial and operating costs of each system were calculated over 25-year service life of the systems, considering tax savings due to depreciation and operating costs, and salvage value of equipment and building and resale price of land in the cash flow analysis. It was shown that the natural gas boiler option provided less expensive energy followed by the wood pellet heat producing technologies, sewer heat recovery, and geothermal heat pump. Amongwood pellet technologies, the grate burner was a less expensive option than powder and gasifier technologies. It was found that using natural gas as a fuel source for the peaking/backup system accounted for 37% of the heat production cost for the considered district-heating center. The results show that the cost of produced heat from wood pellet grate burner is well comparable to that of the natural gas boiler. Emissions of the systems are also calculated in this study. It is shown that the natural gas boiler for the base-load heat productionwould producemore than 4300 tonnes of GHG emission per year, while wood pellet burning systems are GHG neutral. Sensitivity analysis on various inputs to the economic model has been carried out. It was shown that 20% increase in capital cost of the natural gas base-load system or 1%decrease in wood pellet price inflation would make the wood pellet grate burner economically preferable to the natural gas boiler. © 2009 John Wiley & Sons, Ltd.


Ghafghazi S.,University of British Columbia | Sowlati T.,University of British Columbia | Sokhansanj S.,University of British Columbia | Sokhansanj S.,Oak Ridge National Laboratory | And 2 more authors.
Renewable and Sustainable Energy Reviews | Year: 2011

The utilization of wood biomass to generate district heat and power in communities that have access to this energy source is increasing. In this paper the effect of wood fuel properties, combustion condition, and flue gas cleaning system on variation in the amount and formation of particles in the flue gas of typical district heating wood boilers are discussed based on the literature survey. Direct measurements of particulate matter (PM) emissions from wood boilers with district heating applications are reviewed and presented. Finally, recommendations are given regarding the selection of wood fuel, combustion system condition, and flue gas cleaning system in district heating systems in order to meet stringent air quality standards. It is concluded that utilization of high quality wood fuel, such as wood pellets produced from natural, uncontaminated stem wood, would generate the least PM emissions compared to other wood fuel types. Particulate matter emissions from grate burners equipped with electrostatic precipitators when using wood pellets can be well below stringent regulatory emission limit such as particulate emission limit of Metro Vancouver, Canada. © 2011 Elsevier Ltd. All rights reserved.


Ghafghazi S.,University of British Columbia | Sowlati T.,University of British Columbia | Sokhansanj S.,University of British Columbia | Bi X.,Oak Ridge National Laboratory | Melin S.,Delta Research Corporation
International Journal of Life Cycle Assessment | Year: 2011

Purpose There has been an increased interest in utilizing renewable energy sources in district heating systems. District heating systems are centralized systems that provide heat for residential and commercial buildings in a community. While various renewable and conventional energy sources can be used in such systems, many stakeholders are interested in choosing the feasible option with the least environmental impacts. This paper evaluates and compares environmental burdens of alternative energy source options for the base-load of a district heating center in Vancouver, British Columbia (BC) using the life cycle assessment method. The considered energy sources include natural gas, wood pellet, sewer heat, and ground heat. Methods The life cycle stages considered in the LCA model cover all stages from fuel production, fuel transmission/ transportation, construction, operation, and finally demolition of the district heating system. The impact categories were analyzed based on the IMPACT 2002+ method. Results and discussion On a life-cycle basis, the global warming effect of renewable energy options were at least 200 kgeqCO2 less than that of the natural gas option per MWh of heat produced by the base-load system. It was concluded that less than 25% of the upstream global warming impact associated with the wood pellet energy source option was due to transportation activities and about 50% of that was resulted from wood pellet production processes. In comparison with other energy options, the wood pellets option has higher impacts on respiratory of inorganics, terrestrial ecotoxicity, acidification, and nitrification categories. Among renewable options, the global warming impact of heat pump options in the studied case in Vancouver, BC, were lower than the wood pellet option due to BC's low carbon electricity generation profile. Ozone layer depletion and mineral extraction were the highest for the heat pump options due to extensive construction required for these options. Conclusions Natural gas utilization as the primary heat source for district heat production implies environmental complications beyond just the global warming impacts. Diffusing renewable energy sources for generating the base-load district heat would reduce human toxicity, ecosystem quality degradation, global warming, and resource depletion compared to the case of natural gas. Reducing fossil fuel dependency in various stages of wood pellet production can remarkably reduce the upstream global warming impact of using wood pellets for district heat generation. © Springer-Verlag 2011.


Patent
Delta Research LLC | Date: 2015-09-15

A fusion reactor includes an improved ability to modulate a plasma for specific purposes. The reactor operates on the ability to change at least four separate variables in each of a plurality of lenses that are independent of the other lenses. This allows for the generation of Alfvn waves and modulation of the internal plasma dynamics, actively leading to higher states of efficiency. By combining modulation of a plasma in the form of an ion beam with a solid state metal target, an efficient fast neutron source can be produced. This can lead to industrial applications such as energy generation, nuclear clean-up, the production of rare earth metals out of semi-rare ones, and helium production.

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