新疆气化用煤煤质特点及结渣性研究

Coal characteristics and slagging property of Xinjiang coal for gasification

  • 摘要: 新疆煤炭储量丰富,煤质反应活性高,适用于煤电、煤化工生产。煤催化气化技术,作为先进的第3代气化技术,是煤制天然气最有效的工艺途径之一。本研究在新疆伊犁及准东煤化工基地选取6种典型煤种,研究其煤质属性,考察其作为催化气化用煤的适用性。在催化气化工况气氛下利用压差法烧结温度测定装置对各煤灰进行初始烧结温度测试,并结合XRD及Factsage热力学软件计算结果,推测灰中矿物质间的反应及矿物的转变特性,研究矿物质变迁规律,探索结渣性及结渣机理。结果表明,所选地区煤种的煤灰中因难熔化合物氧化铝较低、碱性化合物高,总体灰熔点不高,对于采用固态排渣形式的煤气化工艺具有相对较高的结渣风险。所选煤种总体灰熔点较低,具有高钾钠、低铝特点的准东煤(西黑山、大井矿)更易结渣,用于催化气化工艺结渣风险高。哈密广汇煤具有相对高的熔融温度,作为催化气化工艺用煤结渣较小。负载碳酸钾催化剂后,煤灰烧结温度发生了大幅降低;而钙催化剂添加对烧结温度的影响,受煤种灰成分影响较大。煤灰中硅含量高,添加K催化剂会进一步加剧结渣风险;对于铁含量高的煤,在还原性气氛下,添加K、Ca催化剂均存在较大结渣风险。对于灰分低的煤种,碳酸钾催化剂添加对煤灰熔点及烧结温度影响较大;催化气化工况气氛下,煤灰中硅、铁、钙矿物质的存在使结渣加剧。

     

    Abstract: Xinjiang has abundant coal reserves. Xinjiang coal has high reactivity and is suitable for coal power and coal chemical production. As the third generation of advanced gasification technology,catalytic coal gasification technology is one of the most effective processes for coal to natural gas. Coal characteristics and slagging property of six kinds of Xinjiang coals from lli and Zhundong coal chemical industry base were systematically investigated,and the applicabili- ty of coal for catalytic coal gasification process was inspected,which can provide guidance for the coal selection and utilization of coal to gas project in Xinjiang. A homemade pressurized pressure-drop measuring device was used to de- termine the ash sintering temperature of different coal ash. An X-ray diffractometer (XRD) in combination with Fact- Sage were used to predict the reactions occurring between minerals as well as the mineral transformation and slag for- mation,and reveal the mechanism of slag. The results show that the coal in the selected area has relatively high slag- ging risk for the coal gasification process because of the low refractory compound alumina,high alkaline compound and low ash melting point. The ash melting point of the selected Xinjiang coal is low. XHS and DJ coal with high potassi- um,sodium and low aluminum characteristics are easier to slag,and have a higher slagging risk for catalytic coal gasifi- cation process. The HM coal with relatively high melting temperature is not easy to slag when used for catalytic coal gasification. The sintering temperature of coal loading with potassium carbonate catalyst decreases significantly. The in- fluence of calcium catalyst addition on sintering temperature is greatly influenced by the ash composition of coal. Adding K catalyst will further aggravate slagging when coal ash has higher silicon content. There is a greater slagging risk for coal with higher iron content,and the addition of K and Ca catalysts will aggravate the slagging problem in the reducing atmosphere. For the coal with low ash content,the addition of potassium carbonate catalyst has great influence on the ash melting point and sintering temperature;under the catalytic gasification condition,the presence of silicon,i- ron and calcium minerals in the ash aggravates the slagging.

     

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