Preparation Of Derived Granular Fuel (RDF-5) And It’s Incineration Technology By Co-mixing Sludge And Domestic Waste

In recent years,with the rapid development of economy and people’s living standards,the production of municipal solid waste（MSW）has increased rapidly.Municipal solid waste has those disadvantages like large volume,loose,small density,hardly for transportation and storage.Sludge is unavoidable by-product in waste water treatment processes which has those disadvantages like high viscosity,low calorific value,high moisture content.At the same time,reduce derived fuel（RDF）technology as a new waste treatment technology has been gradually paid attention to and applied in many countries,but there are few researches for making RDF from sludge and municipal solid waste.This investigation takes MSW and combined with sludge to produce refuse derived fuel-5（RDF-5）.This is not only a new attempt to use sludge treating on MSW,but also provides a new idea for the reasonable disposal and effective utilization of MSW.The results of this study will provide scientific support for the recycling of uran solid waste.Firstly,according to the characteristics of municipal solid waste and sludge,we investigate the effects of molding pressure,sludge moisture content and sludge content on the preparation of RDF.On this basis,a pilot system is constructed to produce RDF with uniform shape and good performance.Then we use synthetical thermal analyzer to investigate the TG of RDF-5 under various conditions.In addition,the effects of temperature and sludge content on the combustion performance of RDF were investigated in a tubular furnace by simulated combustion environment.Finally,we applied flue gas analyzer to detect gas pollutants in flue gas of RDF-5incineration.Some conclusions were drawed as following:1.By adding sludge as a binder,when the paper,wood,bamboo,plastic,textile and sludge in the RDF-5’s proportion are 30%,15%,15%,10%and 30%,with 20%sludge moisture content,10MPa forming pressure,RDF-5 has excellent physical and chemical properties:the moisture content is 12%,and the elongation can be controlled within 3%.The particle density reaches 1.23g/cm³,the AR is 0.8%,and 7 day resistance index is 150,which can meet the needs of long-term stacking and long-distance transportation.2.The combustion of RDF-5 particles is mainly divided into three stages:the first is the precipitation of water inside the particles;the second is the precipitation of volatile components in the combustible components,it will combusted faster in this stage;The third stage is the slow weight loss of inorganic oxidation,it will combusted relatively and slow.3.Mixing sludge with municipal solid waste to produce RDF-5 particles can improve the combustion characteristics.When the sludge content is less than 10%,it has little effect on the combustion characteristics.The promotion effect was most intense when the sludge content was10%.When the sludge content is 20%,the burnout rate of RDF-5 decreases to 79%.When the sludge content exceeds 30%,the burnout rate of RDF-5 particles decreases to 69.9%.4.The amount of fly ash produced by the incineration of RDF-5 particles firstly increases and then decreases when the temperature has increased.Fly ash decreased gradually with the increase of sludge content.When the sludge content was 50%,fly ash was less than 8g/kg.5.Under different combustion temperatures,the temperature corresponding to the minimum production of NO_x,SO₂and CO in the combustion of RDF-5 particles is 400℃,400℃and 600℃respectively.However,the yields of NO_xand SO₂at 600℃are higher.The production of NO_xand SO₂of RDF 5 particles increases rapidly,while that of carbon monoxide decreases with the sludge content’s increasing.Therefore,considering the practical application,combustion should be controlled at 600℃,and the sludge content should be kept at about 10%.