Guojun Lv

Bioferment residue: TG-FTIR study and cocombustion in a MSW incineration plant.

With fast development of industry large quantities of hazardous waste are produced in China. Today, incineration plays an important role in the disposal of hazardous waste. Co-incineration of some types of hazardous wastes with municipal solid waste (MSW) has been suggested in the Proposed Standards for Pollutants for MSW combustors in China, published in 2010. According to this proposal, coincinerated hazardous waste should have similar combustion characteristics with MSW, such as bioferment residue (HW02-276-001-02 in China Hazardous Waste List). In this study, residue from the production of hydrochloride salt spectinomycin, a bioferment process, was studied by thermogravimetric analysis (TGA) coupled with Fourier transform infrared (TG-FTIR) analysis. In TGA, the sample attains its final weight before 800 °C. No gaseous pollutants evolve in large amount during FTIR analysis. During test runs at a MSW incineration plant in Jinhua, Zhejiang Province, bioferment residue was added to MSW at a rate of 24 ton/day and fed to the circulated fluidized bed (CFB) incineration system with capacity of 500 ton/day MSW. The operating parameters and emissions were monitored. The system performance was obviously not affected by addition of bioferment residue to MSW/coal and the pollutant emissions met the Chinese standard, with or without addition of bioferment into feedstock.

Co-combustion of tannery sludge in a commercial circulating fluidized bed boiler.

Co-combusting hazardous wastes in existing fluidized bed combustors is an alternative to hazardous waste treatment facilities, in shortage in China. Tannery sludge is a kind of hazardous waste, considered fit for co-combusting with coal in fluidized bedboilers. In this work, co-combustion tests of tannery sludge and bituminous coal were conducted in a power plant in Jiaxing, Zhejiang province. Before that, the combustion behavior of tannery sludge and bituminous were studied by thermogravimetric analysis. Tannery sludge presented higher reactivity than bituminous coal. During the co-combustion tests, the emissions of harmful gases were monitored. The results showed that the pollutant emissions met the Chinese standard except for NOx. The Concentrations of seven trace elements (As, Cr, Cd, Ni, Cu, Pb, Mn) in three exit ash flows (bottom ash in bed, fly ash in filter, and submicrometer aerosol in flue gas) were analyzed. The results of mono-combustion of bituminous coal were compared with those of co-combustion with tannery sludge. It was found that chromium enriched in fly ash. At last, the leachability of fly ash and bottom ash was analyzed. The results showed that most species were almost equal to or below the limits except for As in bottom ashes and Cr in the fly ash of co-combustion test. The concentrations of Cr in leachates of co-combustion ashes are markedly higher than that of coal mono-combustion ashes.

Pyrolysis characteristics and Cr speciation of chrome-tanned leather shavings: influence of pyrolysis temperature

ABSTRACT Chrome-tanned leather shavings (CTLS) are a type of solid waste generated from the leather industry. In this study, the pyrolysis experiment of CTLS was conducted in a high-temperature tubular furnace reactor at different temperatures. The results showed that the pyrolysis temperature highly affected the product yields. The tar generated from the CTLS pyrolysis presented a wide distribution of pyrolytic compounds, and nitrogenated derivatives were the major group. The scanning electronic microscopy (SEM) investigation showed that a continuous structure of irregular but rather uniformly distributed interconnected pores of the chars. Cr was found to exist in the char as its reduced state (Cr3+). This study provided basic data for the determination of pyrolysis temperatures of CTLS targeting different products.