Effects of high temperature and combustion on fluidized material attrition in a fluidized bed

Effect of Heat-Treatment Remediation on the Mechanical Behavior of Oil-Contaminated Soil

The heat treatment of oil-contaminated sites is widely carried out for the purposes of remediation. However, heat treatment changes the physical and chemical properties of soil. Before the soil can be reused as a construction material in civil engineering, such as in backfill or road base materials, the changes to its physical properties must be understood. Therefore, this study investigates the changes in the physical and chemical properties of oil-contaminated soil after heat treatment. In this investigation, experimental samples of soil with added oil from a refinery plant are used to investigate the removal rate of total petroleum hydrocarbons (TPHs) by thermal desorption and incineration. The physical properties of the soil, including water permeability and mechanical properties, are compared before and after heat treatment. The results of this study are as follows. (1) Particle size analysis reveals that heat treatment makes soil particles finer. (2) In the burning reduction test, heat treatment at 900 °C removes more than 90% of THP. (3) In the direct shear test, the friction angle (ϕ) increases with the removal rate. (4) In the hydraulic test, as the removal rate increases, the permeability coefficient increases after heat treatment.

Comparison of the characteristics of bottom and fly ashes generated from various incineration processes

This study analyzed and compared the characteristics of bottom and fly ashes from three municipal solid waste incinerators (MSWIs) in Taiwan. Different incineration furnaces were investigated, including: (1) fluidized bed, (2) mass-burning, and (3) mass-burning linked rotary kiln. The particle size distribution, morphology, mineralogical and chemical composition, and leaching behavior of heavy metals of ash samples were evaluated. The results revealed that three types of incineration processes have different characteristic for ashes due to transportation and mixing system inside furnace. Particle size distribution indicated that 28.5% of MSWI-B bottom ash has lower than 180 microm and 61.2% of MSWI-A fly ash has larger than the 250 microm. The leaching concentration of Pb exceeded the regulatory level set by the Taiwan EPA in fly ashes from MSWI-B and MSWI-C, and thus must be considered hazardous wastes. Specifically, the leaching concentration of heavy metals of fly ashes from MSWI-A (fluidized bed incinerator) was lower than that of the others, and was corresponded to the regulatory levels. Therefore, a fluidized bed incineration process appears a potential of handling heavy metals for ashes. The result was also provided the valuable information for incinerator design and operation.