Hostname: page-component-8448b6f56d-c47g7 Total loading time: 0 Render date: 2024-04-20T01:38:54.759Z Has data issue: false hasContentIssue false
  • English
  • Français

Application of vermiculite and limestone to desulphurization and to the removal of dust during briquette combustion

Published online by Cambridge University Press:  05 July 2018

A. Lu ,
D. Zhao ,
J. Li ,
C. Wang  and
S. Qin
A. Lu*
Affiliation:
Department of Geology, Peking University, Beijing 100871, P. R. China
D. Zhao
Affiliation:
Electron Microscopy Center and Department of Geological Sciences, University of South Carolina, 701 Sumter St., Columbia, SC 29208, USA
J. Li
Affiliation:
School of Materials Science and Technology, China University of Geosciences, Beijing 100083, P R China
C. Wang
Affiliation:
Department of Geology, Peking University, Beijing 100871, P. R. China
S. Qin
Affiliation:
Department of Geology, Peking University, Beijing 100871, P. R. China
*
* E-mail: ahlu@pku.edu.cn
Get access Rights & Permissions [Opens in a new window]

Abstract

Small domestic cooking furnaces are widely used in China. These cooking furnaces release SO2 gas and dust into the atmosphere and cause serious air pollution. Experiments were conducted to investigate the effects of vermiculite, limestone or CaCO3, and combustion temperature and time on desulphurization and dust removal during briquette combustion in small domestic cooking furnaces. Additives used in the coal are vermiculite, CaCO3 and bentonite. Vermiculite is used for its expansion property to improve the contact between CaCO3 and SO2 and to convey O2 into the interior of briquette; CaCO3 is used as a chemical reactant to react with SO2 to form CaSO4; and bentonite is used to develop briquette strength. Expansion of vermiculite develops loose interior structures, such as pores or cracks, inside the briquette, and thus brings enough oxygen for combustion and sulphation reaction. Effective combustion of the original carbon reduces amounts of dust in the fly ash. X-ray diffraction, optical microscopy, and scanning electron microscopy with energy dispersive X-ray analysis show that S exists in the ash only as anhydrite CaSO4, a product of SO2 reacting with CaCO3 and O2. The formation of CaSO4 effectively reduces or eliminates SO2 emission from coal combustion. The major factors controlling S retention are vermiculite, CaCO3 and combustion temperature. The S retention ratio increases with increasing vermiculite amount at 950°C. The S retention ratio also increases with increasing Ca/S molar ratio, and the best Ca/S ratio is 2-3 for most combustion. With 12 g of the original coal, 1 to 2 g of vermiculite, a molar Ca/S ratio of 2.55 by adding CaCO3, and some bentonite, a S retention ratio >65% can be readily achieved. The highest S retention ratio of 97.9% is achieved at 950°C with addition of 2 g of vermiculite, a Ca/S ratio of 2.55 and bentonite.

Keywords

coaldesulphurizationdust removalair pollutionvermiculiteCaCO3briquetteashChina
Type
Research Article
Information
Mineralogical Magazine , Volume 67 , Issue 6 , December 2003 , pp. 1243 - 1251
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2003

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abbasian, J., Rehmat, A., Leppin, D. and Barnejee, D.D. (1990) Desulfurization of fuels with calcium-based sorbents. Fuel Process Technology 25, 1—5.CrossRefGoogle Scholar
Berman, Y., Tanklevsky, A., Oren, Y. and Tamir, A. (2000a Modeling and experimental studies of SO2absorption in coaxial cylinders with impinging streams: part I. Chemical Engineering Science, 55, 1009—1021.CrossRefGoogle Scholar
Berman, Y., Tanklevsky, A., Oren, Y. and Tamir, A. (2000b Modeling and experimental studies of SO2absorption in coaxial cylinders with impinging streams: part II. Chemical Engineering Science, 55, 1023—1028.CrossRefGoogle Scholar
Cao, Z. and Zhong, H. (1999) New progress in study on additive for briquetted coal. Fuel & Chemical Processes, 30, 269—271.Google Scholar
Chang, L.P., Zhu, S.Y. and Ye, J.L. (1996) The effects of silica and ferric oxide on limestone capturing sulfur during coal combustion. Environmental Chemistry, 17, 89—90.Google Scholar
Davini, P. (2001) Investigation into the desulfuration properties of by-products of the manufacture of white marbles of northern Tuscany. Fuel, 79, 1363—1369.CrossRefGoogle Scholar
Elena, A. and Juan, F.G. (1999) High pressure thermogravimetric analysis of the direct sulfation of Spanish calcium-based sorbent. Fuel, 78, 341—348.Google Scholar
Jose, V.I., Jose, M.P. and de Andres, A.M. (1989) Analysis of coal and char ashes and their ability for sulphur retention. Fuel, 68, 861—867.Google Scholar
Kamphuis, B., Potma, A.W., Prins, W. and Van Swaaij, W.P.M. (1993) The reductive decomposition of calcium sulphate - I. Kinetics of the apparent solid-solid reaction. Chemical Engineering Science, 48, 105—116.CrossRefGoogle Scholar
Laursen, K., Duo, W., Grace, J.R. and Lim, J. (2000) Sulfation and reactivation characteristics of nine limestones. Fuel, 79, 153—163.CrossRefGoogle Scholar
Li, J.H., Lu, A.H. and Gao, Y.H. (2001a) The characteristics of local coal dusts and environmental mineralogical materials used for desulfuration. Earth Science Frontiers, 8, 316—320.CrossRefGoogle Scholar
Li, J.H., Lu, A.H., Chen, C.X. and Zhen, X.S. (2001b) The application of vermiculite to desulphurization and dust clearing during coal combustion. Ada Petrologica et Mineralogica, 20, 515—519.Google Scholar
Liu, H., Katagiri, S., Kaneko, U. and Okazaki, K. (2000) Sulfation behavior of limestone under high CO2concentration in O2/CO2 coal combustion. Fuel, 79, 945—953.CrossRefGoogle Scholar
Lu, A.H. (1999) The application of environmental mineral materials to the treatment of contaminated soil, water and air. Ada Petrologica et Mineralogica, 18, 293—299.Google Scholar
Lu, A.H. (2000) Development of properties of mineralogy from resource to environment. Geological Journal of China Universities, 6, 245—251.Google Scholar
Ma, X.X., Takao, K., Tsutomu, T., Tadashi, Y. and Kunio, K. (2000) Use of limestone for SO2 removal from flue gas in the semidry FGD process with a powder-particle spouted bed. Chemical Engineering Science, 55, 4643—4652.CrossRefGoogle Scholar
Marta, G.C., Gregorio, M. and Antonio, B.F. (2000) Decomposition of CaS particles at ambient condi-tions. Chemical Engineering Science, 55, 1661—1674.Google Scholar
Naijar, M.S. and Jung, D.Y. (1995) High temperature desulfurization of synthesis gas with iron com-pounds. Fuel Processing Technology, 44, 173—180.CrossRefGoogle Scholar
Pineda, M., Palacios, J.M., Alonso, L., Garcia, E. and Moliner, R. (2000) Performance of zinc oxide based sorbents for hot coal gas desulfuration in multicycle tests in a fixed-bed reactor. Fuel, 79, 885—895.CrossRefGoogle Scholar
Qiu, K.R., Oliver, L. and Tobias, M. (1999) Oxidation behaviour of desulphurization residues from gasifca-tion and fuel-rich combustion. Fuel, 78, 225—231.CrossRefGoogle Scholar
TSBCEP (Technological Standard Bureau of China Environmental Protection) (1997) The Introduction of Applied Technology of Removing Dust and Desulfuration on both Middle and Small Type Industrial Coal Combusting Boiler. China Environmental Science Publishing Company, Beijing, China.Google Scholar
Xiao, P.L. and Li, S.N. (1996) Fe-Si series additives affection on sulphur transform during briquetted coal combustion. Ada Scientiae Cirumstantiae, 16, 97—101.Google Scholar
Xu, R.Q. and Cao, J.C. (1993) A mineralogical study of vermiculite from Tseganbrark Xinjiang. Ada Mineralogica Sinica, 13, 37—45.Google Scholar
Yrjas, P., Iisa, K. and Hupa, M. (1995) Limestone and dolomite as sulfur adsorbents under pressurized gasification conditions. Fuel, 75, 89—95.CrossRefGoogle Scholar
Zhang, L.Q., Cheng, S.W. and Yan, R.X. (1997) Discussion on the desulfuration mechanism of briquetted coal by Fe2O3 . Environmental Science, 18, 65—67.Google Scholar
Zhou, S.Y. (1985) Applying Coal Petrography. Metallurgy Industrial Publishing Company, Beijing, China.Google Scholar