scholarly journals Partition of Cu and Pb in a Two-Stage Fluidized-Bed Waste Gasification System

2019 ◽  
Vol 9 (8) ◽  
pp. 1576 ◽  
Author(s):  
Chiou-Liang Lin ◽  
Jing-Dong Chou ◽  
Wang-Chang Weng
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Fluidized Bed ◽  
Operating Temperature ◽  
Two Stage ◽  
Factors Affecting ◽  
Bed Materials ◽  
Major Factors ◽  
Stage 1 ◽  
Bed Material

In this study, a two-stage fluidized-bed gasification system was used to determine the distribution of heavy metal contaminants in simulative waste and evaluate the effect of the bed operating temperature, Equivalence ratio (ER), and Steam/Biomass ratio (S/B) in stage 1. The heavy metal concentrations in bed materials and fly ash were measured in two stages. The results show that as the operating temperature of stage 1 increased, the quantity of heavy metals entrapped by stage 1 bed material decreased, while that captured by stage 2 bed material increased. The less volatile Cu was mostly entrapped in stage 1 bed material. The ER and S/B results show that increasing the ER and S/B caused a slight increase in the concentrations of heavy metals entrapped in stage 1 and stage 2 bed materials. However, the influences of ER and S/B were less than that of temperature. The major factors affecting the heavy metal distribution were the operating temperature and the heavy metal volatility. Stage 2 bed material was able to entrap gaseous heavy metals or particles containing heavy metals by particle filtration and chemical adsorption. Thus, the heavy metals (Cu and Pb) had a downward trend after passing through stage 2.

scholarly journals Heavy metal uptake and stress in food crops: A Review

2021 ◽  
Vol 13 (4) ◽  
pp. 323-332
Author(s):  
N. Abdullahi ◽  
E.C. Igwe ◽  
M.A. Dandago
Keyword(s):  
Heavy Metal ◽  
Defense Mechanisms ◽  
Food Contamination ◽  
Chemical Properties ◽  
Growth Yield ◽  
Control Measures ◽  
Food Crops ◽  
Factors Affecting ◽  
Root And Shoot Length ◽  
Major Factors

Abstract. Heavy metal (HM) food contamination is detrimental to food safety and human health. Water scarcity, food shortage, illiteracy, failure to enforce environmental protection laws, and food quality regulations account for human HM contamination. Understanding their uptake pattern in food crops and how the crops behave under excessive concentration of these hazardous chemicals will guide farmers, researchers, and policymakers in devising appropriate control measures that will ensure the production and consumption of safer food crops. Relevant texts published by Science Direct, Springer Nature, and Wiley between January 2018 and December 2020 were cited in this article. The article discussed major factors affecting HM accumulation and the effects of HM stress on yield, physiology, and chemical properties of food crops. Wastewater irrigation, production in contaminated soil, and atmospheric deposit contributed to the contamination. Factors that influence HM uptake are those related to soil and irrigation water qualities and plant properties. The presence of other HMs and chemicals, growing season, crop age, planting method, and food crop type also affect HM uptake in food crops. HM stress affects anatomy, physiology including antioxidant defense mechanisms, nutrient availability and uptake, germination, seedlings development, growth, yield, leaf geometry, root and shoot length, plant genetics, pollination, and chemical composition including moisture content, soluble protein, and pigment content and characteristics.

Thermal treatment of soil co-contaminated with lube oil and heavy metals in a low-temperature two-stage fluidized bed incinerator

2016 ◽  
Vol 93 ◽  
pp. 131-138 ◽  
Author(s):  
Ukrit Samaksaman ◽  
Tzu-Huan Peng ◽  
Jia-Hong Kuo ◽  
Chien-Hsing Lu ◽  
Ming-Yen Wey
Keyword(s):  
Heavy Metals ◽  
Thermal Treatment ◽  
Low Temperature ◽  
Fluidized Bed ◽  
Two Stage

Experimental Research on Impacts of Operation Parameters on Agglomeration Characteristics during CFB Biomass Gasification

2014 ◽  
Vol 556-562 ◽  
pp. 375-379
Author(s):  
Xiao Xu Fan ◽  
Li Guo Yang ◽  
Hui Liang Zhang ◽  
Hong Jian Chen
Keyword(s):  
Fluidized Bed ◽  
Biomass Gasification ◽  
High Alumina ◽  
Cotton Stalk ◽  
Air Velocity ◽  
Bed Materials ◽  
Operation Parameters ◽  
Bed Agglomeration ◽  
Bed Material ◽  
Return Valve

The impacts of operation parameters on agglomeration characteristics during biomass gasification in fluidized bed were studied experimentally in a 0.02MWt CFB gasifier using cotton stalk pellet as fuel. The experimental results indicated that among the temperature range (600 °C-800 °C), bed agglomeration would occur after a period running with sand, high alumina bauxite or periclase as the bed material, and potassium gathered on the surface of bed materials. In the process of the fluidized-bed gasification of biomass, air velocity affected the degree of bed agglomeration, and the agglomeration problem in return valve was more serious than that in main bed.

Mechanisms of Bed Material Agglomeration in a Petroleum Coke-Fired Circulating Fluidized Bed Boiler

1998 ◽  
Vol 120 (3) ◽  
pp. 215-218 ◽  
Author(s):  
B.-J. Skrifvars ◽  
M. Hupa ◽  
E. J. Anthony
Keyword(s):  
Fluidized Bed ◽  
Petroleum Coke ◽  
Circulating Fluidized Bed ◽  
Solid Particles ◽  
Circulating Fluidized Bed Boiler ◽  
Neck Growth ◽  
Heat Treated ◽  
Gas Atmosphere ◽  
Bed Materials ◽  
Bed Material

Petroleum coke firing in a circulating fluidized bed boiler has sometimes been reported to be associated with cyclone deposit problems and return leg plugging. In this paper, we present data which indicate that some of these problems may be due to the calcium-rich bed material used during the firing. We have earlier shown that calcium oxide may react with the flue gas components SO2 or CO2, causing neck growth between the solid particles. This neck growth between particles may lead to both deposits in the cyclone and plugging of the cyclone return leg. In this study we made use of a sintering testing method, based on compressive strength tests of heat-treated cylindrical pellets. Laboratory-prepared petroleum coke ash was mixed with two potential bed materials, limestone and dolomite, and sintering tests were performed in three different gas atmospheres. Significant differences were found between the mixtures as a function of both the gas atmosphere and temperature. We also performed thermogravimetric analyses on one of the bed materials, the limestone. Based on these results a mechanism for the formation of cyclone deposits and bed material agglomeration in the return leg was suggested.

scholarly journals Eutrophication and sediment–water exchange of total petroleum hydrocarbons and heavy metals of Hashilan wetland, a national heritage in NW Iran

2021 ◽  
Author(s):  
Sajjad Abbasi ◽  
Sara Sheikh Fakhradini ◽  
Neamatollah Jaafarzadeh ◽  
Pooria Ebrahimi ◽  
Shirin Yavar Ashayeri
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Ecological Risk ◽  
Petroleum Hydrocarbons ◽  
Principal Component ◽  
Potential Ecological Risk ◽  
Total Petroleum Hydrocarbons ◽  
Pollution Indices ◽  
Factors Affecting ◽  
Nw Iran

AbstractThe heavy metal(loid)s concentrations in water and sediments were analyzed in the Hashilan wetland to assess the spatial distribution, pollution status, fate, partitioning, and ecological risk and also to identify the heavy metal(loid)s sources in sediments using PMF (Positive Matrix Factorization) and APCs-MLR (absolute principal component score-multiple linear regression) receptor models. According to the pollution indices, (Ni, Cu, Cr, Mo), and (Zn, Cr, and Cu) are considered the most important pollutants in sediments and water, respectively. Ni, Cr, and Cu are the main contributors to ecological risks in sediments of some stations. The potential ecological risk assessment proposed low ecological risk in water of the study area. Higher distribution coefficient (Kp) values of Ni, Cr, Mn, Cu, Co, Pb, As, and Zn indicated the majority of these heavy metals present in the sediments; whereas, the majority of Cd concentration occurs in water. PMF and APCs-MLR results indicated the natural sources were the main factors affecting the concentrations of Ni, Cr, Zn, Al, Co, Fe, Pb, As, Cd and somewhat Cu. Mixed natural and agricultural activities are the main sources of Mo, and somewhat Cu. According to the results, there is low pollution of TPH (total petroleum hydrocarbons) in the sediment samples. Also, phosphate (PO42−) and nitrate (NO3−) concentrations were below the recommended permissible limits at all sampling sites except the S8 station for NO3−.

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