Effect of additives on ash sintering behaviors and gasification performance in catalytic coal gasification process

doi:10.11949/j.issn.0438-1157.20181359

Abstract

Abstract:

The introduction of alkali metal catalyst in the coal catalytic gasification process exacerbates the slagging of the gasification furnace and directly affects the normal operation of the fluidized bed gasifier. The sintering characteristic of coal ash is one of the main factors affecting slag formation in fluidized bed gasifier. In this paper a self-made pressurized pressure-drop measuring device combining analysis of X-ray diffractometer (XRD) analyzer and simulation calculation of Factsage thermodynamic software were used to study the effects of different additives addition on sintering temperature of Wangjiata bituminous coal from Inner Mongolia and gasification performance in catalytic coal gasification process. Silicon aluminum additives improved the sintering temperature of coal ash. Compared with silicon additives, the addition of high aluminum additives had more obvious effect on improving the sintering temperature of coal ash. High aluminum additives can be used as an efficient refractory flux, but it reduced coal gasification activity and catalyst recovery rate, it was because of the reaction of additives with catalyst in gasification, and thus the catalytic performance of catalyst decreased. Addition of calcium oxide, the ash fusion temperature and sintering temperature of coal ash increased, and the coal gasification activity and catalyst recovery rate also improved. The ash melting point and sintering temperature increased with the increase of CaO content. Calcium oxide can be used as an additive to improve the slagging properties of coal in catalytic gasification process. And the additive content should be determined according to the nature of coal and the characteristics of the coal gasification process.

Key words: catalytic coal gasification, sintering temperature, silicon aluminum additive, calcium oxide, gasification performance

摘要：

煤催化气化工艺中碱金属催化剂的引入加剧了气化炉的结渣，直接影响了流化床气化炉的正常操作。煤灰的烧结特性是流化床气化炉结渣的主要影响因素之一。通过自制的压差法烧结温度测定实验装置，并结合XRD 等分析表征及Factsage热力学软件模拟计算，考察了不同添加剂对煤灰烧结特性及气化性能的影响，并从矿物学角度探讨了添加剂对煤灰结渣特性及气化工艺的影响。结果表明，添加硅铝系添加剂可提高煤灰的烧结温度；相比硅系添加剂，添加高铝系添加剂对改善煤灰的烧结温度效果更明显；高铝系添加剂可作为一种高效的阻熔剂，但因在气化过程中容易同催化剂反应，导致催化剂催化性能降低，对煤的气化活性及催化剂回收率产生不利影响；添加氧化钙添加剂，煤的灰熔温度及烧结温度均增加，随氧化钙含量增加，灰熔点及烧结温度均升高，且对气化活性及催化剂回收率有良性作用；氧化钙可作为改善煤种结渣性的添加剂用于催化气化工艺中，需根据煤种性质及工艺特点确定适宜的添加量。

关键词: 催化气化, 烧结温度, 硅铝系添加剂, 氧化钙, 气化性能

CLC Number:

TQ 53
TQ 54

Yandong MAO, Kezhong LI, Lei LIU, Feng XIN. Effect of additives on ash sintering behaviors and gasification performance in catalytic coal gasification process[J]. CIESC Journal, 2019, 70(5): 1951-1963.

毛燕东, 李克忠, 刘雷, 辛峰. 添加剂对催化气化工艺中煤灰结渣性及气化性能影响研究[J]. 化工学报, 2019, 70(5): 1951-1963.

Figures/Tables 16

Table 1 Analysis of samples

Sample	Proximate analysis/%(mass)			Ultimate analysis/%(mass)				Ash fusion temperature^①/℃
Sample	M_ad	A_d	V_d	C_d	H_d	N_d	S_d	DT	ST	HT	FT
WJT	10.15	6.9	32.92	71.25	4.1	0.76	0.15	1144	1264	1318	1355

Table 2 Composition analysis of Al, Si-containing additives

Additive	Composition/%
Additive	Al₂O₃	SiO₂
alumina	> 99
kaoline	45.68	50.76
diatomite	3.19	83.80
silicon dioxide		> 99

Fig.1 Diagram of pyrolysis device

Fig.2 Diagram of pressurized fixed bed test device

Table 3 Ash fusion temperatures of samples

Sample	Ash fusion temperature^①/℃(Reducing atmosphere^②)
Sample	DT	ST	HT	FT
WJT-K	1008	1034	1076	1131
WJT-K-Al	1350	1381	1392	1420
WJT-K-Ka	1309	1342	1360	1389
WJT-K-Si	1084	1126	1183	1204
WJT-K-Di	1116	1153	1209	1231

Fig.3 Initial formation temperature of slag from Factsage of ash samples

Fig.4 Effect of Al, Si-containing additives on sintering temperature

Fig.5 Phase diagram for K2O-Al2O3-SiO2 compositions

Fig.6 XRD results of samples after sintering temperature test

Fig.7 XRD patterns of char samples and gasified ash samples before and after adding alumina to WJT-K

Fig.8 27Al NMR of different samples

Table 4 Ash fusion temperatures of samples

Sample	Ash fusion temperature^①/℃(Reducing atmosphere^②)
Sample	DT	ST	HT	FT
WJT-K	1008	1034	1076	1131
WJT-K-Ca 30	1056	1083	1106	1124
WJT-K- Ca 40	1068	1119	1179	1194
WJT-K- Ca 50	1121	1238	1301	1336

Fig.9 Initial formation temperature of slag from Factsage of ash samples

Fig.10 Effect of CaO additive on sintering temperature

Fig.11 Phase diagram for CaO-Al2O3-SiO2 compositions

Fig.12 XRD patterns of samples after sintering temperature test

References 35

1	焦嶕, 赵国浩, 张宝建 . 中国煤炭产业可持续发展策略: 基于系统基模的研究[J]. 经济问题, 2018, (3): 79-84.
	Jiao J , Zhao G H , Zhang B J . Study on sustainable development strategy of China s coal industry — based on systems archetypes [J]. Economic Problem, 2018, (3): 79-84.
2	周利红, 于永玲 . 煤催化气化制天然气专利技术进展[J]. 当代石油石化, 2015, 23(4): 21-26.
	Zhou L H , Yu Y L . The progress of patented technology in coal-based synthetic natural gas by catalytic gasification [J]. Petroleum & Petrochemical Today, 2015, 23(4): 21-26.
3	毛燕东, 毕继诚, 李金来, 等 . 一种由煤催化气化制甲烷的方法: 201010532452.6 [P]. 2010-11-02.
	Mao Y D , Bi J C , Li J L , et al . A method for producing methane by catalytic gasification of coal: 201010532452.6 [P]. 2010-11-02.
4	毛燕东, 李克忠, 孙志强, 等 . 小型流化床燃煤自供热煤催化气化特性研究[J]. 高校化学工程学报, 2013, 27(5): 798-804.
	Mao Y D , Li K Z , Sun Z Q , et al . Characteristics of catalytic coal gasification in lab scale auto thermal fluidized bed [J]. J. Chem. Eng. Chin. Univ., 2013, 27(5): 798-804.
5	Hippo E J , Sheth A C . Mild catalytic steam gasification process: US2007/0000177 A1 [P]. 2007-01-04.
6	毛燕东, 金亚丹, 王会芳, 等 . 煤催化气化工艺中碱金属腐蚀刚玉质耐火材料的实验研究[J]. 燃料化学学报, 2014, 42(11): 1332-1339．
	Mao Y D , Jin Y D , Wang H F , et al . Experimental research on corrosions of corundum refractory by alkali metals in catalytic coal gasification process [J]. J. Fuel Chem. Technol., 2014, 42(11): 1332-1339.
7	周明灿 . 煤制天然气产业发展及技术分析[J]. 化工设计, 2017, 27(6): 7-10.
	Zhou M C . Development of coal-based natural gas industry and technical analysis [J]. Chemical Engineering Design, 2017, 27(6): 7-10.
8	井云环 . 煤催化气化技术进展[J]. 当代化工, 2016, 45(6): 1273-1275.
	Jing Y H . Research progress of catalytic coal gasification technology [J]. Contemporary Chemical Industry, 2016, 45(6): 1273-1275.
9	王鹏飞, 王航, 崔龙鹏, 等 . 新一代煤气化技术展望[J]. 炼油技术与工程, 2014, 44(8): 1-5.
	Wang P F , Wang H , Cui L P , et al . Outlook of new generation coal gasification technologies [J]. Petroleum Refinery Engineering, 2014, 44(8): 1-5.
10	Mao Y D , Jin Y D , Li K Z , et al . Sintering characteristic in catalytic gasification of China Inner Mongolia bituminous coal ash [J]. Energy Fuels, 2016, (30): 3975-3985.
11	Schmitt V , Kaltschmitt M . Effect of straw proportion and Ca and Al-containing additives on ash composition and sintering of woodstraw pellets[J]. Fuel, 2013, 109(7): 551-558.
12	Lin W , Johansen K D , Frandsen F . Agglomeration in bio-fuel fired fluidized bed combustors [J]. Chem. Eng. J., 2003, 96(2): 171-185.
13	毛燕东, 金亚丹, 李克忠, 等 . 煤催化气化工艺中内蒙王家塔烟煤灰烧结温度的影响因素分析[J]. 化工学报, 2015, 66(3): 1080-1087.
	Mao Y D , Jin Y D , Li K Z , et al . Analysis of influencing factors on sintering temperature of Inner Mongolia Wangjiata bituminous coal ash during catalytic coal gasification [J]. CIESC Journal, 2015, 66(3): 1080-1087.
14	Khan A , De J W , Jansens P , et al . Biomass combustion in fluidized bed boilers: potential problems and remedies [J]. Fuel Process Technol., 2009, 90(1): 21-50.
15	Demirbas A . Potential applications of renewable energy sources, biomass combustion problems in boiler power systems and combustion related environmental issues [J]. Prog. Energy Combust Sci., 2005, 31(2): 171-192.
16	Easterly J L , Burnham M ．Overview of biomass and waste fuel resources for power production [J].Biomass Bioenergy, 1996, 10(2): 79-92.
17	Heinzel T , Siegle V , Spliethoff H , et al . Investigation of slagging in pulverized fuel co-combustion of biomass and coal at a pilot-scale test facility [J]. Fuel Process Technol., 1998, 54(1): 109-125.
18	Bartels M , Lin W G , Nijenhuis J , et al . Agglomeration in fluidized beds at high temperatures: mechanisms, detection and prevention [J]. Prog. Energy Combust. Sci., 2008, 34(5): 633-666.
19	Gupta S K , Gupta R P , Bryantg W , et al . The effect of potassium on the fusibility of coal ashes with high silica and alumina levels [J]. Fuel, 1998, 77(11): 1195-1201.
20	Al-Otoom A Y , Elliott L K , Moghtaderi B , et al . The sintering temperature of ash, agglomeration, and defluidisation in a bench scale PFBC [J]. Fuel, 2005, 84(1): 109-114.
21	Habibi R , Kopyscinski J , Masnadi M S , et al . Co-gasification of biomass and non-biomass feed stocks: synergistic and inhibition effects of switch grass mixed with sub-bituminous coal and fluid coke during CO₂ gasification [J]. Energy Fuels, 2012, (27): 494-500.
22	Wang J , Sakanishi K , Saito I , et al . High-yield hydrogen production by steam gasification of hyper coal (ash-free coal extract) with potassium carbonate: comparison with raw coal [J]. Energy Fuels, 2005, (19): 2114-2120.
23	Jing N J , Wang Q H , Cheng L M , et al . The sintering behavior of coal ash under pressurized conditions [J]. Fuel, 2013, (103): 87-93.
24	毛燕东, 金亚丹, 李克忠, 等 . 煤催化气化条件下不同煤种煤灰烧结行为研究[J]. 燃料化学学报, 2015, 43(4): 402-409.
	Mao Y D , Jin Y D , Li K Z , et al . Sintering behavior of different coal ashes in catalytic coal gasification process [J]. Journal of Fuel Chemistry and Technology, 2015, 43(4): 402-409.
25	Zhang J G , Li J B , Mao Y D , et al . Effect of CaCO₃ addition on ash sintering behaviour during K₂CO₃ catalysed steam gasification of a Chinese lignite [J]. Applied Thermal Engineering, 2017, (111): 503-509.
26	Jiang M Q , Zhou R , Hu J , et al . Calcium-promoted catalytic activity of potassium carbonate for steam gasification of coal char: influences of calcium species [J]. Fuel, 2012, (99): 64-71.
27	Jiang M , Hu J , Wang J . Calcium-promoted catalytic activity of potassium carbonate for steam gasification of coal char: effect of hydrothermal pretreatment [J]. Fuel, 2013, (109): 14-20.
28	Song W J , Tang L H , Zhu X D , et al . Effect of coal ash composition on ash fusion temperatures [J]. Energy Fuels, 2010, (24): 182-189.
29	Li F H , Huang J J , Fang Y T . Fusibility characteristics of residual ash from lignite fluidized-bed gasification to understand its formation [J]. Energy Fuels, 2012, (26): 5020-5027.
30	Jing N J , Wang Q H , Yang Y K , et al . Influence of ash composition on the sintering behavior during pressurized combustion and gasification process [J]. Appl. Phys. Eng., 2012, 13(3): 230-238.
31	Matjie R H , French D , Ward C R , et al . Behaviour of coal mineral matter in sintering and slagging of ash during the gasification process [J]. Fuel Process. Technol., 2011, (92): 1426-1433.
32	Zhang J G , Zhang L , Yang Z Q , et al . Effect of bauxite additives on ash sintering characteristics during the K₂CO₃-catalyzed steam gasification of lignite [J]. RSC Adv., 2015, (5): 6720-6727.
33	姚奕竑 . 经钙基添加剂预处理煤碳酸钾催化气化研究[D]. 上海: 华东理工大学, 2008.
	Yao Y H . A study on potassium-carbonate-catalyzed coal gasification by pretreatment with calcium-based additions [D]. Shanghai: East China University of Science and Technology, 2008.
34	姜明泉 . 煤焦碱金属催化水蒸气气化-产氢行为和催化剂性能的研究[D]. 上海: 华东理工大学, 2012.
	Jiang M Q . The study on alkali-catalyzed gasification of coal char: behaviors of hydrogen production and performances of the catalysts [D]. Shanghai: East China University of Science and Technology, 2012.
35	王兴军, 陈凡敏, 刘海峰, 等 . 煤水蒸气气化过程中钾催化剂与矿物质的相互作用[J]. 燃料化学学报, 2013, 41(1): 9-13.
	Wang X J , Chen F M , Liu H F , et al . Interaction of potassium with mineral matter in coal during steam gasification [J]. Journal of Fuel Chemistry and Technology, 2013, 41(1): 9-13.

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