The Research On Papermaking Sludge Co-firing In Grate Furnace

Since the reform and opening up. with China's rapid economic development, the needs of various industries on the paper gradually increase each year, the economic development of the paper demand for products to promote paper industry boomingly. In the year of 2009. nation emissions of paper industry wastewater was 3.67 billion tons, only 92% of which has been discharged within standards. A large number of paper mill sludge has been produced during the wastewater treatment process. This paper took paper sludge from the Hua County Light Paper Co. Ltd for the study objective and studied the paper sludge's buring conditions.In the paper sludge drying experiment, we found the sludge drying process can be divided into three parts:the early section of the crack, the crack development and slow dry section. During the interval, the sludge water content decreased rapidly in a short time. Through the calorific value of paper mill sludge laboratory analysis done in the laboratory and industry analysis, it showed the water content of paper mill sludge and calorific value is a negative correlation.Paper sludge co-fire with coal in the grate furnace in different water content experiment. We can learn that the paper sludge with 48.9% water content got exhaust temperature changes.the highest temperature is 187.1℃,the lowest temperature is 161.2℃.they had 25.9℃variation:and the water content 9.8% papermaking sludge exhaust temperature variation amplitude.the highest temperature of minimum 183.2℃the lowest temperature relatively 165.2℃variation amplitude for for 18℃. Slime mix in different than paper-making sludge with coal-fired&coal mixing trials, select 4:1,3:1,2:1 three different mixing ratio, we found that 4:1 mixing ratio, highest temperature and minimum temperature differ 13.4℃comparing the mix ratio 2:1 which with 21.8℃, it is small.Finally, the experimental researched paper sludge co-firing with coal in grate furnace in different working conditions. Through the changes of the wind chamber with wind speed to observe stoker, we found that increased the ratio of the front of the wind room and reduce back-end (the proportion of each change aroun 10%) under the condition of the stocker speed increase, steam temperature, exhaust temperature and temperature of grate furnace are not adjusted than enhancing; While the adjustment with wind speed conditions(increase the speed of grate from 4.2m/h to 5m/h), we found furnace temperature and steam temperature drop first small at first, then it increased rapidly until it reached in the point 1009℃and 177.7℃, which was similar to the initial conditions without any changes.Through the above several groups of testing, we got the conclusion. With grate furnace grate speed settled at 5m/h, with the four wind room ratio adjusted at 25%, 35%,30%,10%, with water content of paper sludge aroud 30%. with coal and paper sludge mixing ratio adjusted 3:1 ratio, the condition of the grate furnace can reach the best state.