| With the rapid development of China's economy and the construction of new countryside,rural living garbage harmless treatment and recycling has become China's major livelihood projects and environmental energy engineering research.The research and development of pyrolysis can promote the gasification technology,waste recycling and inhibition of dioxins,which will be of great importance in conservation of land resources and the environment protection energy saving and emission reduction.In this paper,the optimization design and development conditions of pyrolysis and gasification of waste pyrolysis and gasification furnace as the goal,to refuse a region of Fujian as the object of study on pyrolysis of waste process the apparent kinetic parameters of pyrolysis and gasification furnace,parameter optimization,optimal operation conditions and water vapor on the modified gas.To provide the basis for the design and operation of gasification furnace.The main research contents and results include:Taking typical one-component waste as research objec,using thermogravimetric analyzer under constant heating rate,we analysis pyrolysis characteristics of typical one-component living garbage(leaves,PE,PVC,rubber,fabric,paper and wood chips)and actual mixture fraction of living garbage,as well as the mixture garbages composed by typical one-component according to the actual waste under the condition of constant temperature.It was found that the highest activation energy difference is PE(323 kJ/mol),PVC is the second one(206.6 kJ/mol),leaves in the first pyrolysis is lowest(14 kJ/mol);Mixed waste is similar with fitting mixed waste on pyrolysis TG curve in 400 ?,but the fitting mixed waste pyrolysis residue content is 18.9%,while the actual mixed waste pyrolysis weight loss rate of 36%.Pyrolysis temperature range is basical same,and pyrolysis activation energy gradually decreased with the temperature increasing,the temperature is conducive to the pyrolysis of solid waste.Making the actual living garbage in a given area of Fujian as an object,and a rotary kiln waste pyrolysis furnace and updraft fixed-bed gasifier were designed according to the requirement of the capacity(10 t/d).Results show that in rotary kiln,removing the incombustible material of garbage,and keeping moisture content under 21.8%,living garbage can happen pyrolysis reaction byself,and without external heat source heating.The furnace cold filling rate is 13%,slope 2.5% residence time 40 min,furnace volume 5.36 m3,long 6.8 m,diameter 1.16 m,height is 3.9 m;The size of the gasifier design is relatively complex,the high diameter rate is about 3:1generally,design gasifier gasification intensity is 270 kg/(h.m~2),cross section area is 1.3 m~2,the thick of clay refractory layer is 20~30 mm gasifier.The gasification gas production is 756 m3/h,the heat exchange rate is 285.576 MJ/h,the heat exchange area is 1.07 m~2,the diameter of the pipe is mm DN15 mm,the length of the pipe is 11.3 m,and the condensed water flow rate is 2 m/s.Keeping the updraft fixed-bed gasifier in Fujian as object,choosing gasification temperature,gasification medium access amount,the bed height on the single factor to analysis,then using the method of orthogonal test to select the best conditions of gasification.It was found that elevated temperature can improve the efficiency of gasification,but has some limitations;ER > 0.36,gasification efficiency drops rapidly when the airflow over gasifier self balancing ability;The best effect achieved when H/D is 3:1.For the gasifier(?3×16 m)with 50 t/d capacity,the highest gasification efficiency(79.3%)could be achieved when the gasification temperature,air volume and height of material layer were 750?,2600 m3/h and 9 m,respectively.The equivalence ratio was the main factors influencing the gasification efficiency,gasification temperature was the second,and the height of material layer was the minimum one.The tar and carbon conversion rate were 9.2~22.5 g/m3 and 74.5~85.9%,respectively.Dioxin levels was far lower than the national standard,the blackness was 1,pollutants were good meet the national discharge standard in addition to sulfur dioxide which was slightly higher than the national discharge standard.Making the fuel gas out of updraft fixed-bed gasifier as an object,controlling the water vapor and carbon ratio(S/C)in order to modified fuel gas by using Fluent software.The simulation results show that the quantity of primary fuel gas heat production(13198 MJ/h)promoted to 229971 MJ/h(S/C=2),continuing to increase the water vapor,the quantity of fuel gas heat production up to 31345 MJ(S/C=2.5)and 31116.4 MJ/h(S/C=3).It was worth noting that the quantity of tar export was about 9.2~22.5 g/m3,It was still have 16363~17737 MJ/h heat production increased in spite of the 13608 MJ/h heat production of tar which was transform into fuel gas at upgrading process.This suggested that the effect of fuel gas modification was remarkable. |
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