Research On Carbonaceous Solid Waste For Briquette Additive And Analysis Of Briquette Characteristics

In recent years, the global ecological environment remains severe and the concept of environmental protection is gradually enhanced. The pollution is mainly originated from the use of fossil fuels. Coal is the primary fossil energy in China. Coal clean combustion is the focus area of the energy sustainable development in China. The briquette technology is a kind of developed clean coal technology with a long history owing to its high efficiency utilization development mode.This study use the combustible solid waste and pulverized coal to prepare molded solid fuel based on clean coal briquette technology and fuel properties of combustible solid waste (crop straw, sewage sludge). In this study, the following three aspects were carried out. On the one hand, develop new type of briquette additives of composite boiler briquette using the combustible solid waste. On the other hand, develop the functional additives of composite briquette to solve the problems of low briquette mechanical strength, worse waterproof performance and poor desulphurization efficiency. For the third, study the combustion and pollution characteristics of the composite briquette and explore the combustion mechanism of combustible solid waste and pulverized coal. The results show that:(1) Considering adding a certain amount of sludge as coal briquette additive. The results show that the sludge in the composite briquette played a role of the binder. The mechanical strength reached the highest point with the addition of the sludge being20%. The indexes of coal briquette comprising of the compressive strength, thermal strength, thermal stability, drop strength and waterproof strength could reach the standard of local industrial coal briquette of Shanxi with the addition of6%betonies and1.8%silicone waterproof.(2) The emission characteristics of S and N were analyzed by flue gas analyzer and the sulfur retention of composite briquette aimed at SO2 pollution was studied. The results showed that the sludge inhibited the emissions of SO2and NOx. The sulfur retention rate of Ca(OH)2was only about42%. The addition of alkali melt salts increased the sulfur retention efficiency obviously. The sulfur retention rate reached83.43%with the addition of K2CO3.(3) The addition of fermentation modified biomass in coal briquette increases the compressive strength of the briquette owing to the biomass with dense texture, good compression performance and worse expansion. When the addition of the fermentation modified biomass was15%and the sludge was20%, the mechanical strength of the composite coal briquette was the optimal value of1.3MPa which was still lower than the standard of local industrial coal briquette of Shanxi.(4) The combustion characteristics were studied using integrated thermal analyzer and ash melting point test technology. The results showed that the addition of sludge and biomass decreased the burning point, improved the combustion capability, increased the burn-out rate of slag and decreased the melting point of the slag.