석탄-물 혼합연료의 제조와 유변학적 특성화

김동호; 김도현

Korean Journal of Rheology, Vol.10, No.3, 131-136, September, 1998

Export Citation

석탄-물 혼합연료의 제조와 유변학적 특성화

Preparation and Rheological Characterization of Coal-Water Mixture

김동호, 김도현

초록

아역청탄을 이용하여 제조된 CWM(Coal-Water Mixture)연료의 유변학적 특성을 측정함으로써 음이온 계면활성제 Temol-N, 안정제 Xanthan 및 전해질 등의 첨가제에 대한 성능을 평가하고 최적첨가조성을 결정하였다. 계면활성제의 흡착으로 인해 석탄입자는 음전하를 띠게 되었고 표면에 전기 이중층이 생성되었다. 전기 이중층의 전기적 반발력이 입자의 응집을 막았고, CWM 슬러리의 점도를 감소시켰다. 또한 Xanthan과 NaOH의 첨가로 인해 분산안정성 및 침강안정성이 향상되는 것을 관찰하였다. CWM에서 석탄입자가 차지하는 부피비를 무게비로 전환하여 표현하고, 분산계에서 입자의 부피비에 따른 점도변화를 예측하는 실험식인 Krieger-Dougherty식과 Frankel-Acrivos식에 적용하였다. 점도 실험값을 가지고 식의 변수들을 결정해 본 결과, CWM이 나타내는 점도의 석탄함량에 따른 변화를 위 식들이 비교적 정확히 나타내 주는 것을 확인하였다.

The effects of additives such as Temol-N surfactant, Xanthan and electrolyte on the rheological properties of CWM made of subbituminous coal were investigated to determine the optimum composition for the phase stability. The surface of coal particles became negatively charged by the adsorption of surfactant and electric double layer was formed on the surface. Repulsive force by the electric double layer prevented the aggregation of particles and reduced the slurry viscosity. The addition of Xanthan and sodium hydroxide was shown to improve the suspension and sedimentation stability of CWM. Weight fraction of coal particles in CWM was converted to the volume fraction by defining the appropriate parameters and the results were applied to the semi-empirical expressions proposed by krieger-Dougherty and Frankel-Acrivos. By fitting experimental data, parameters of these equations could be determined and these equations were found to be appropriate for representing the solid weight fraction-viscosity relationship for concentrated CWM slurry.

Keywords:Coal-Water Mixture;Suspension;Rheological Properties;Krieger-Dougherty Equation;Frankel-Acrivos Equation

[References]

Lee S, "Alternative Fuels," Taylor & Francis, ch. 6 (1996)
Roh NS, Ph.D. Thesis, Dept. of Chemical Engineering, KAIST (1996)
Papachristodoulou G, Trass O, Powder Technol., 40, 353 (1984)
Roh NS, Shin DH, Kim DC, Kim JD, Fuel, 74, 1220 (1995)
Carniani E, Donati E, Ercolani D, Ferroni E, Gabreilli G, Proc. of the 14th Int. Conf. on Coal & Slurry Technology, Clearwater, Fla., April 24-27, 553 (1989)
Cho YI, Choi US, Trans. ASME J. Energy Resources Technol., 112, 36 (1990)
Kaji R, Muranaka Y, Miyadera H, Hishinuma Y, AIChE J., 33, 11 (1987)
Nishino J, Kiyama K, Seki M, J. Chem. Eng. Jpn., 22, 162 (1989)
Saeki T, Usui H, Ogawa M, J. Chem. Eng. Jpn., 27(6), 773 (1994)
Yamauchi J, Terada K, Sato T, Okaya T, J. Appl. Polym. Sci., 55(11), 1553 (1995)
Probstein RF, "Physicochemical Hydrodynamics," 2ed., John Wiley & Sons, p. 277 (1994)
Dabak T, Yucel O, Rheol. Acta, 25, 527 (1986)
Krieger IM, Adv. Colloid Interface Sci., 3, 111 (1972)
Frankel NA, Acrivos A, Chem. Eng. Sci., 22, 847 (1967)

[1] Lee S, "Alternative Fuels," Taylor & Francis, ch. 6 (1996)

[2] Roh NS, Ph.D. Thesis, Dept. of Chemical Engineering, KAIST (1996)

[3] Papachristodoulou G, Trass O, Powder Technol., 40, 353 (1984)

[4] Roh NS, Shin DH, Kim DC, Kim JD, Fuel, 74, 1220 (1995)

[5] Carniani E, Donati E, Ercolani D, Ferroni E, Gabreilli G, Proc. of the 14th Int. Conf. on Coal & Slurry Technology, Clearwater, Fla., April 24-27, 553 (1989)

[6] Cho YI, Choi US, Trans. ASME J. Energy Resources Technol., 112, 36 (1990)

[7] Kaji R, Muranaka Y, Miyadera H, Hishinuma Y, AIChE J., 33, 11 (1987)

[8] Nishino J, Kiyama K, Seki M, J. Chem. Eng. Jpn., 22, 162 (1989)

[9] Saeki T, Usui H, Ogawa M, J. Chem. Eng. Jpn., 27(6), 773 (1994)

[10] Yamauchi J, Terada K, Sato T, Okaya T, J. Appl. Polym. Sci., 55(11), 1553 (1995)

[11] Probstein RF, "Physicochemical Hydrodynamics," 2ed., John Wiley & Sons, p. 277 (1994)

[12] Dabak T, Yucel O, Rheol. Acta, 25, 527 (1986)

[13] Krieger IM, Adv. Colloid Interface Sci., 3, 111 (1972)

[14] Frankel NA, Acrivos A, Chem. Eng. Sci., 22, 847 (1967)