Study On Combustion And Pore Structure Characteristic Of Sewage Sludge And Coal

Sewage sludge production has been increased rapidly with the fast developingeconomy in our country. It will cause serious pollution if the sludge can’t get effectivetreatment. In addition, the sludge also contained a certain amount of organic matter, itis a waste of the resources if we don’t put it to use. Burn it in the incinerator is aneffective method. According to the actual situation in our country, co-combustion ofsludge and coal is chosed.Basic analysis, ash melting characteristic, combustion characteristic and porestructure characteristic of sewage sludge and coal were studied in order to providerelevant reference for the design of sludge and coal mixed boiler.The main content of this article are as follows:1. Through the basic analysis of sludge and coal, we found that sludge with ahigher proportion of ash and volatile, lower carbon fixed and calorific value comparedwith coal.2. Fusion characteristic of mixing fuel ash under differert mixing proportionwere studied by pyramid method, and found as the sludge content rising in blends,fusion characteristic temperatures of ash reduce, but not a linear relationship.3. Thermogravimetric analysis of sewage sludge and coal was studied. The resultshows the combustion characteristic of mixed samples are influenced by both of them,even better than sludge or coal burning along in some characteristic parameters. Thebest mixing ratio of sludge and coal got in this experiment is 3:7.4. Pore structure characteristic of sewage sludge and coal was studied by N2adsorption-desorption method. The results shows that the specific surface area of fuelparticles presented in the tendency of first rising and then declining with the burn-outratio increases and it changes fastest at the sludge ratio of 30%. The ad-sorptionisothermal curves obtained from the samples are adsorption isothermal curves of typeⅡandⅣor typeⅠ,ⅡandⅣ. All of them contains the typeⅡ, which means allthe samples have a relatively continuous and integral pore system with pore diametersranging from the smallest molecular grade to the largest without an upperlimit(relatively). Sludge has larger pore diameter and less micropores, moremesopores and macropores compared with coal. The BJH adsorption average porewidth increases sharply after the mix of sewage sludge and coal. The best mixproportion of sludge and coal got in this experiment is 3:7. We find the best mixing ratio is the same in these two experiments.