兰炭具有热值高、灰分低、硫分低等优点，但挥发分含量低、着火温度高；秸秆热值低、挥发分含量高，着火温度低；二者着火特性具有互补性。为考察兰炭与生物质混合燃料燃烧的硫氧化物、氮氧化物排放和灰熔融性能，利用固定床试验系统研究了3种兰炭、麦秆和玉米秆单独及混合燃料污染物排放特性及掺混比例和燃烧温度对污染物析出的影响，并通过灰熔融测定仪分析灰样熔融性能。结果表明：混合燃料的硫氧化物、氮氧化物析出与掺混条件相关，原料组成和燃烧过程影响污染物析出特性。在燃料中掺混20%～30%玉米秆时，混合燃料固硫效果较好，氮析出率在0.04%左右。提高燃烧温度明显促进硫析出，而低于1 000 ℃时，府谷兰炭和玉米秆的掺混样具备良好的自固硫特性，氮析出率低于0.02%。另外，混合燃料的灰熔融温度介于两原样间，与混合比例存在一定相关性，兰炭的抗结渣特性明显优于玉米秆，掺混有助于改善秸秆的结渣特性。本研究为兰炭和生物质的清洁利用提供理论参考。

Semi-coke has the advantages of high calorific value, low ash content, and low sulfur content, but low volatile content and high ignition temperature. Straw has low calorific value, high volatile content and low ignition temperature. The ignition characteristics between the semi-coke and straw are complementary. In order to investigate  the emissionsof sulfur oxides, nitrogen oxides and ash melting performance of semi-coke mixed with biomass fuel combustion, the fixed bed experimental system was used to study three kinds of semi-coke from different regions, wheat straw, corn straw and the mixed fuel pollutant emission characteristics respectively, and the influence of mixing proportion and combustion temperature on pollutant discharge, and the ash melting performance was analyzed by the ash fusion analyzer. The results show that the release of sulfur oxide and nitrogen oxide from the mixed fuel is related to the mixing conditions, and the composition of raw materials and combustion process affect the pollutant release characteristics. When 20%-30% corn stalk is mixed into the fuel, the mixed fuel shows a good sulfur fixation effect, and the nitrogen release rate is about 0.04%. Sulfur precipitation is significantly promoted by raising the combustion temperature. When the combustion temperature is lower than 1 000 ℃, the mixed fuel of Fugu semi-coke and corn stalk have good self-sulfur fixation characteristics, and the nitrogen release rate is lower than 0.02%. In addition, the ash melting characteristic temperature of the mixed fuel is between the temperature of original semi-coke and corn stalk, which has a certain relationship with the mixing ratio. The anti-slagging property of semi-coke is significantly better than that of corn stalk, which is helpful to improve the slagging property of straw by mixing. The results of this study provide theoretical reference for clean utilization of semi-coke and biomass.

0 引言

1 试验

   1.1 试验样品

   1.2 试验方法及仪器 

   1.3 试验计算方法和评价指标

2 结果与讨论

   2.1 兰炭和秸秆单独燃烧时硫氮污染物排放特性

   2.2 不同秸秆对硫氮污染物排放特性的影响

   2.3 不同兰炭对硫氮污染物排放特性的影响

   2.4 燃烧温度对污染物排放特性的影响

   2.5 混合燃料灰熔融特性

3 结论