Hanjing Wu

University of Nebraska at Lincoln, Lincoln, NE, United States

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Publications (3)3.41 Total impact

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    ABSTRACT: Thermogravimetric analysis was used to examine the thermal behavior of dairy manure as a pyrolysis and combustion feedstock. Nitrogen and air were used as purging gases to analyze the pyrolysis and combustion reactions, respectively, and heating rates of 20°C min(-1), 40°C min(-1) and 60°C min(-1) were applied. An Arrhenius model was used to estimate the kinetic parameters (activation energy, reaction order and pre-exponential factor). Results showed four steps for both the pyrolysis and the combustion reactions, with the second step being the most critical one and during which most thermal decomposition of cellulose, hemicelluloses, starch and protein occurred. Thermochemical reactions were determined mainly by temperature. Heating rate influenced the start and the end of the thermal conversions. The activation energies for the two major reaction zones were 93.63 kJ mol(-1) and 84.53 kJ mol(-1) for pyrolysis, and 83.03 kJ mol(-1) and 55.65 kJ mol(-1) for combustion. Knowledge of the thermal behavior of dairy manure provides guidelines for future energy utilization.
    Waste management & research : the journal of the International Solid Wastes and Public Cleansing Association, ISWA. 07/2012; 30(10):1066-71.
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    ABSTRACT: Application of excessive animal manure to the land may cause some environmental problems such as eutrophication of surface waters, degradation of ground water quality, and threats to human health. This paper reports an experimental study on the technology of biomass gasification to treat animal waste by analysing the effects of key operating parameters on gasification. In this research, dairy manure from the University of Nebraska dairy farm was first collected and dried, and then gasified in a fluidized-bed, laboratory-scale gasifier to generate syngas. The effects of three parameters, namely temperature, steam to biomass ratio (SBR) and the equivalence ratio (ER), on the gasification were described by a Box-Behnken design (BBD). Results showed that increasing the temperature favoured the formation of all three combustible gases, but the composition of each gas behaved differently according to the changing parameters. The lower heating value of the syngas varied from 2.0 to 4.7 MJ m(-3), indicating gasification could be used as a waste management option to produce bioenergy, and potentially reduce problems associated with the disposal of animal waste.
    Waste management & research : the journal of the International Solid Wastes and Public Cleansing Association, ISWA. 11/2011; 30(5):506-11.
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    ABSTRACT: Animal waste is an important source of anthropogenic GHG emissions, and in most cases, manure is managed by land application. Nevertheless, due to the huge amounts of manure produced annually, alternative manure management practices have been proposed, one of which is gasification, aimed to convert manure into clean energy-syngas. Syngas can be utilized to provide energy or power. At the same time, the byproduct of gasification, biochar, can be transported back to fields as a soil amendment. Environmental impacts are crucial in selecting the appropriate manure strategy. Therefore, GHG emissions during manure management systems (land application and gasification) were evaluated and compared by life cycle assessment (LCA) in our study. LCA is a universally accepted tool to determine GHG emissions associated with every stage of a system. Results showed that the net GHG emissions in land application scenario and gasification scenario were 119 and -643 kg CO2-eq for one tonne of dry feedlot manure, respectively. Moreover, sensitive factors in the gasification scenario were efficiency of the biomass integrated gasification combined cycle (BIGCC) system and energy source of avoided electricity generation. Overall, due to the environmental effects of syngas and biochar, gasification of feedlot manure is a much more promising technique as a way to reduce GHG emissions than is land application.
    Biomass and Bioenergy 54:260–266. · 3.41 Impact Factor

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3.41 Total Impact Points

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Institutions

  • 2011–2012
    • University of Nebraska at Lincoln
      • Industrial Agricultural Products Center
      Lincoln, NE, United States