Experimental and Simulation Studies of Corn Kernel Gasification in a Double Air Stage Downdraft Reactor

2018 ◽  
Author(s):  
Yunye Shi ◽  
Diego M. Yepes Maya ◽  
Regis Nascimento ◽  
Tejasvi Sharma ◽  
Albert Ratner ◽  
...  
Keyword(s):  
Experimental Tests ◽  
Producer Gas ◽  
Simulation Studies ◽  
Corn Kernel ◽  
Two Stage ◽  
Combustible Gas ◽  
Air Supply ◽  
Simulation Based ◽  
Gasification Efficiency ◽  
Combustible Gas Mixture

Biomass gasification is the devolatilization and incomplete combustion of biomass resulting in the production of a combustible gas mixture including carbon monoxide (CO), hydrogen (H2) methane (CH4), and traces of other hydrocarbons (CnHm), and referred to as producer gas. Producer gas can be cleaned and then used in various engines or can be converted to various biofuels. This paper presents an experimental and simulation-based evaluation of producer gas quality resulting from corn kernel gasification in a two-stage downdraft gasifier. Test conditions were selected, based on the results of previous studies, to yield high conversion efficiency and low tar production. Experimental tests were performed with an air flow of 25 Nm3/h and with 80% of the air supplied to the first gasification stage. Simulations based on a chemical and thermal equilibrium model were carried out to examine the effect of equivalence ratio (ER) changes. Both the experimental and modelling results show that using a two-stage air supply leads to a significant reduction in the tar content of the producer gas, while maintaining a high gasification efficiency.

scholarly journals Gasification of Pelletized Corn Residues with Oxygen Enriched Air and Steam

2019 ◽  
Vol 8 (3) ◽  
pp. 215-224 ◽  
Author(s):  
Poramate Sittisun ◽  
Nakorn Tippayawong ◽  
Sirivatch Shimpalee
Keyword(s):  
Oxygen Concentration ◽  
Equivalence Ratio ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Producer Gas ◽  
Combustible Gas ◽  
Product Gas ◽  
Biomass Ratio ◽  
Gasification Efficiency ◽  
Corn Residues

This work studied generation of producer gas using oxygen-enriched air and steam mixture as gasifying medium. Corn residues consisting of cobs and stover were used as biomass feedstock. Both corn residues were pelletized and gasified separately with normal air, oxygen enriched air and steam mixture in a fixed bed reactor. Effects of oxygen concentration in enriched air (21-50%), equivalence ratio (0.15-0.35), and steam to biomass ratio (0-0.8) on the yield of product gas, the combustible gas composition such as H2, CO, and CH4, the lower heating value (LHV), and the gasification efficiency were investigated. It was found that the decrease in nitrogen dilution in oxygen enriched air increased proportion of combustible gas components, improved the LHV of producer gas, but gasification efficiency was not affected. The increase in equivalence ratio favoured high product gas yield but decreased combustible gas components and LHV. It was also observed that introduction of steam enhanced H2 production but excessive steam degraded fuel gas quality and decreased gasification efficiency. The highest gasification efficiency of each oxygen concentration was at equivalence ratio of 0.3 and steam to biomass ratio of 0.58 for cob, and 0.22 and 0.68 for stover, respectively. ©2019. CBIORE-IJRED. All rights reserved

Autotrophic biosynthesis of polyhydroxyalkanoate by Ralstonia eutropha from non-combustible gas mixture with low hydrogen content

2020 ◽  
Vol 42 (9) ◽  
pp. 1655-1662 ◽  
Author(s):  
Yuki Miyahara ◽  
Masahiro Yamamoto ◽  
Romeo Thorbecke ◽  
Shoji Mizuno ◽  
Takeharu Tsuge
Keyword(s):  
Hydrogen Content ◽  
Ralstonia Eutropha ◽  
Gas Mixture ◽  
Combustible Gas ◽  
Combustible Gas Mixture

Simulation-based verification of homogenization approach in predicting effective thermal conductivities of wavy orthotropic fiber composite

2019 ◽  
Vol 08 (04) ◽  
pp. 1950015
Author(s):  
C. Mahesh ◽  
K. Govindarajulu ◽  
V. Balakrishna Murthy
Keyword(s):  
Volume Fraction ◽  
Fiber Composite ◽  
Micromechanical Model ◽  
Two Stage ◽  
Micromechanics Models ◽  
Simulation Based ◽  
Homogenization Approach ◽  
Homogenized Model ◽  
Good Agreement ◽  
Thermal Conductivities

In this work, applicability of homogenization approach is verified with the micromechanics approach by considering wavy orthotropic fiber composite. Thermal conductivities of [Formula: see text]-300 orthotropic wavy fiber composite are determined for micromechanical model and compared with the results obtained by two stage homogenized model over volume fraction ranging from 0.1 to 0.6. Also, a methodology is suggested for reducing percentage deviation between homogenization and micromechanical approaches. Effect of debond on the thermal conductivities of wavy orthotrophic fiber composite is studied and compared with perfectly aligned fiber composite for different volume fraction. It is observed that results obtained by the homogenization approach are in good agreement with the results obtained through micromechanics approach. Maximum percentage deviation between homogenized and micromechanics models is 2.13%.

scholarly journals A Technology of Multiple Smelting Furnaces per Termite Mound: Iron Production in Chongwe, Lusaka, Zambia

2020 ◽  
Vol 18 (1) ◽  
pp. 67-85
Author(s):  
Edwinus C. Lyaya ◽  
Shadreck Chirikure ◽  
Philip E. Janney ◽  
Thilo Rehren
Keyword(s):  
Liquid Slag ◽  
Spatial Organization ◽  
Sub Saharan Africa ◽  
Iron Production ◽  
Smelting Product ◽  
Termite Mound ◽  
Two Stage ◽  
Field Evidence ◽  
Air Supply ◽  
Stage Process

Abstract With exception of Maluma (1979) and Musambachime (2016, 2017), there have been no archaeometallurgical publications on the technology and culture of iron production in Zambia. This paper presents archaeological and archaeometallurgical evidence of a technology of iron production in Chongwe in terms of spatial organization, the process of metal production (either a three-stage process involving smelting in relatively tall furnaces, refining in miniature (vintengwe) furnaces, and smithing on a hearth or a two-stage process involving smelting and smithing), furnace air supply mechanisms, liquid slag handling techniques, variation in the geochemistry of ore and clay, and the nature of the final smelting products. Archaeological field data collection techniques included ethnoarchaeological interviews, (furnace) excavation, surface collections, and surface walkover surveys, while laboratory analytical techniques included optical microscopy (OM), scanning electron microscopy (SEM), and x-ray fluorescence (XRF). New field evidence indicates that iron production in Chongwe in the previous two centuries was secluded from respective pre-modern settlements for socio-cultural and technical reasons. There are no settlement remains in and around Chongwe smelting sites. Also, most of the archaeological data in Chongwe are supportive of the two-stage process that did not involve iron refining in vintengwe furnaces. There were no iron refining sites in Chongwe. Archaeological evidence also strongly points to the use of natural air supply mechanism for the smelting furnaces because proximal ends of tuyères inter alia were not trumpeted. All smelting sites were systematically located on termite mounds. There were three to four smelting furnaces located on the western side of a termite mound. The presence of tuyère mould slags and thin and elongated slag microstructures strongly indicates that liquid slag was tapped outside the furnace apparently through tuyères and was left to cool quickly. Presence of primary wüstite and iron particles in the slags strongly suggests the production of iron as the final smelting product in Chongwe. The results are compared with the archaeology, chemistry, and mineralogy of iron production from other parts of sub-Saharan Africa, particularly in the Lake Tanganyika-Nyasa Corridor. The presence of three to four smelting furnaces per termite mound makes iron production in Chongwe a unique technology in the Corridor.

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