碱性氢氧化物消除NH4Cl积灰特性实验研究

通过模拟燃煤电厂中NH₄Cl氛围，研究NH₄Cl如何影响飞灰沉积引起受热面热流密度变化. 实验采用竖式炉系统模拟锅炉尾部烟道，油循环系统控制温度，探针收集积灰，实时监测探针内外表面温度，获得探针受热面热流密度，将NaOH，Mg(OH)₂，Ca(OH)₂作为脱除剂，研究3种碱性氢氧化物对烟气中NH₄Cl的脱除效果. 研究发现，NH₄Cl对灰分的黏附能力较弱，受热面热流密度降低主要由NH₄Cl析出形成的沉积层引起. 在3种脱除剂中，Ca(OH)₂能够改善探针顶部热流密度降低，将热流密度降低率缩小到3.61%；NaOH能够改善探针底部热流密度降低，将降低率缩小到6.46%；Mg(OH)₂虽然能够减少探针顶部热流密度降低，但会引起探针底部热流密度降低加剧.

Experimental study on characteristics of alkaline hydroxide to eliminate NH4Cl ash deposition

By simulating the atmosphere of NH₄Cl in coal-fired power plants, the rules that how NH₄Cl caused ash deposition to affect the heat flux density of the heat-transfer surfaces were studied. A drop tube furnace system was used to simulate the boiler tail flue, an oil circulation system for temperature control, a probe system for ash deposition, the temperature inside and outside of the probe was monitored in real time to obtain the heat flux density on the probe surface. NaOH, Mg(OH)₂, and Ca(OH)₂ were used as additives to study the removing effect of three alkaline hydroxides on NH₄Cl in the flue gas. Results showed that NH₄Cl had a weak adhesion ability to ash, and the decrease in heat flux density on the heat-transfer surface was mainly caused by the deposition of NH₄Cl. Among the three additives, Ca(OH)₂ could narrow the decrease of heat flux density on the top of the probe, reducing the ratio of the decrease to 3.61%, while NaOH could narrow the decrease of the heat flux density at the bottom of the probe, reducing the ratio of the decrease to 6.46%. Although Mg(OH)₂ could reduce the decrease of the heat flux density at the top of the probe, it would enlarge the decrease of the heat flux density at the bottom of the probe.