This paper addresses the syngas production and evaluation losses in high temperature gasification process using coffee husks. A fast and inexpensive way to evaluate the losses in gasification processes is by the appli...This paper addresses the syngas production and evaluation losses in high temperature gasification process using coffee husks. A fast and inexpensive way to evaluate the losses in gasification processes is by the application mathematical models which allow to predict the values needed in full scale. Hence, the quantification of gasifier’s losses at temperatures ranges of 800 K - 1400 K at an equivalence ratios of 0.3, 0.35 and 0.4 at 1 bar are revealed by using exergy model incorporating a chemical equilibrium model. The model evaluated the product syngas compositions, syngas heating values and degree of irreversibility values (losses). The results from the model showed that the production of H2 increased from 9.9% to 18.9% and the formation of CO2 ranges from 7.2% to 12.3%. CO production is from 21.8% to 17.2%. The irreversibility values obtained were less than 27%. Hence, reduction of losses protracts biomass resources to be used in energy generation.展开更多
We have investigated the magnetic transition and magnetocaloric effects of Mn1＋xCo1-xGe alloys by tuning the ratio of Mn/Co. With increasing Mn content, a series of first-order magnetostructural transitions from ferr...We have investigated the magnetic transition and magnetocaloric effects of Mn1＋xCo1-xGe alloys by tuning the ratio of Mn/Co. With increasing Mn content, a series of first-order magnetostructural transitions from ferromagnetic to paramagnetic states with large changes of magnetization are observed at room temperature. Further increasing the content of Mn （x = 0.11） gives rise to a single second-order magnetic transition. Interestingly, large low-field magnetic entropy changes with almost zero magnetic hysteresis are observed in these alloys. The effects of Mn/Co ratio on magnetic transition and magnetocaloric effects are discussed in this paper.展开更多
Losses in turbine cascade are categorized as profile loss, secondary loss, tip clearance loss and annulus loss. Profile loss occurs due to development of boundary layer on surface of blade [1]. Increase in thickness o...Losses in turbine cascade are categorized as profile loss, secondary loss, tip clearance loss and annulus loss. Profile loss occurs due to development of boundary layer on surface of blade [1]. Increase in thickness of boundary layer and adverse pressure gradient increases profile loss. Secondary loss occurs due to turning of flow through flow passage which results in blowing of energy from pressure side to suction side. In turbine rotor blade suction surface leads and tip clearance loss occurs due to leakage of air from pressure side to suction side of the blade through tip clearance. Annulus loss occurs due to development of boundary layer on stationary row of blade. It also occurs in moving row of blade but in moving row of blades boundary layer is scraped by flow over the blades. This paper presents effects of variation of pitch-chord ratio on secondary loss.展开更多
文摘This paper addresses the syngas production and evaluation losses in high temperature gasification process using coffee husks. A fast and inexpensive way to evaluate the losses in gasification processes is by the application mathematical models which allow to predict the values needed in full scale. Hence, the quantification of gasifier’s losses at temperatures ranges of 800 K - 1400 K at an equivalence ratios of 0.3, 0.35 and 0.4 at 1 bar are revealed by using exergy model incorporating a chemical equilibrium model. The model evaluated the product syngas compositions, syngas heating values and degree of irreversibility values (losses). The results from the model showed that the production of H2 increased from 9.9% to 18.9% and the formation of CO2 ranges from 7.2% to 12.3%. CO production is from 21.8% to 17.2%. The irreversibility values obtained were less than 27%. Hence, reduction of losses protracts biomass resources to be used in energy generation.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 50701022,51001019,and 50831006)the Program for New Century Excellent Talents of China (Grant No. NCET-08-0278)
文摘We have investigated the magnetic transition and magnetocaloric effects of Mn1＋xCo1-xGe alloys by tuning the ratio of Mn/Co. With increasing Mn content, a series of first-order magnetostructural transitions from ferromagnetic to paramagnetic states with large changes of magnetization are observed at room temperature. Further increasing the content of Mn （x = 0.11） gives rise to a single second-order magnetic transition. Interestingly, large low-field magnetic entropy changes with almost zero magnetic hysteresis are observed in these alloys. The effects of Mn/Co ratio on magnetic transition and magnetocaloric effects are discussed in this paper.
文摘Losses in turbine cascade are categorized as profile loss, secondary loss, tip clearance loss and annulus loss. Profile loss occurs due to development of boundary layer on surface of blade [1]. Increase in thickness of boundary layer and adverse pressure gradient increases profile loss. Secondary loss occurs due to turning of flow through flow passage which results in blowing of energy from pressure side to suction side. In turbine rotor blade suction surface leads and tip clearance loss occurs due to leakage of air from pressure side to suction side of the blade through tip clearance. Annulus loss occurs due to development of boundary layer on stationary row of blade. It also occurs in moving row of blade but in moving row of blades boundary layer is scraped by flow over the blades. This paper presents effects of variation of pitch-chord ratio on secondary loss.
