Slagging and fluidity behavior of coal ash under gasifier environment

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:324745

Kim, H T; Bae, H J ^[1]; Lee, S H; Park, J S ^[2]; Yun, Y S; Chung, S W ^[3]

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1. Ajou Univ., Suwon (Korea, Republic of). Energy Dept.
2. Korea Inst. of Energy Research, Daejon (Korea, Republic of)
3. Inst. of Advanced Engineering, Suwon (Korea, Republic of). Electric Power Systems Lab.

The objective of this study is to predict the slagging and fluidity behavior of coal ashes from the physical/chemical properties of parent coals to determine the optimum operating parameter of a slagging-type coal gasifier. Three types of coal samples, such as Alaska Usibelli, China Datong and Posco (blended coal), are analyzed for their ash composition and ash fusion temperature. To investigate the effect of flux addition on ash slagging behavior, optimum quantity of CaO addition is evaluated with considering negative effect of CaO addition on gasification reaction. The effect of blending of Posco coal with Alaska and Datong coal on ash slagging is also investigated to expand the variety and performance of coal types in slagging-type entrained-bed gasifier. The results of the experiment shows that the optimum CaO fluxing quantity is 10%, 20% on Alaska and Dating coal, respectively. However, optimum blending ratio for ash slagging is not found when mixing Posco coal with Alaska or Datong coals. Melting and slagging characteristics of coal ash samples with changing temperature are examined in detail by DTA. ASTM ash melting temperatures as well as critical viscosity temperature are compared with TGA and DTA profiles. DTA experiments illustrate that coal ash starts to melt before the IDT (initial deformation temperature) and that theoretical T{sub CV} is well correlated with DTA profile. Experiment of ash fluidity are also carried on with the Alaska and Datong coal ashes using a high temperature viscometer. The experimental viscosity data is compared with the calculated viscosity and results show good correlation. As a result, viscosity of coal ash could be calculated with the Watt and Fereday equation in the high temperature range. The experimental results from this investigation will be used as reference data for determining optimum operating condition of 3t/d bench scale unit gasifier which is located in Ajou University, Suwon, Korea.

• OSTI ID: 324745
• Report Number(s): CONF-970931--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ASH CONTENT
ASHES
BROWN COAL
CALCIUM OXIDES
CHEMICAL PROPERTIES
COAL GASIFICATION
GAS GENERATORS
PHYSICAL PROPERTIES
RHEOLOGY
SLAGS
SUBBITUMINOUS COAL
VISCOSITY