ASH DEPOSIT CHARACTERISTICS OF BLENDED COAL IN COAL COMBUSTION PROCESS

Coal combustion process often occurs the problems in the reactor which is caused by fouling and slagging. One of the procedures to reduce the risk of fouling and slagging by blending the coal of Pendopo, Palangkaraya, Muara Enim and Samarinda, with the ratio of 25:75, 50:50, and 75:25. The ash deposit tendency is known by analyzing the composition and ash fusion temperature of coal, determining the ash type and calculating of the fouling and slagging. The results showed that the Pendopo and Palangkaraya coal with a ratio of 25:75 and 50:50 were classified as lignite with fouling and the slagging index was classified as a high and medium tendency. While the other blended coal was classified as a low and low-medium tendency

STUDY OF ADDITIVE, SIZE FRACTION AND COAL CONCENTRATION FOR COAL WATER FUEL

Coal Water Fuel (CWF) is one of energy diversifications. It enables the coal to substitute fuel oil by existing installations because CWF could flow similar to the flow of liquid. Selections of additive, coal size fraction, ratio coal and water of CWF were studied in laboratory scale. Arutmin coal, processed with Upgraded Brown Coal (UBC) technology, was grouped to -60 and -200 meshes and then are mixed with water and small quantities of additive. Size fraction, coal concentration and additive type were varied to investigate their effects on CWF behavior. Results from concentration and penetration tests show that the best additive for CWF with size fraction - 200 mesh is DBS (Doacely Benzene Sulfanat) with optimum coal concentration is 51% using size - 60 mesh indicate, that the most stable CWF was resulted from CWF using DBS with optimum coal concentration 55 %. Results of using different size fraction that show the decrease of concentration and penetration rate from CWF with size fraction - 200 mesh is relatively constant compared to the CWF with size fraction – 60 mesh

UTILIZATION OF COAL ACTIVATED CARBON AS ADSORBENT AMMONIUM WITH THE HIGH CONCENTRATION

Ammonium adsorption process carried out by batch system, with making 208-233 mg/L concentration of am- monium solution. In the adsorption batch systems, particle size of activated carbon -8 + 12 mesh and -16 + 20 mesh was added into 200 ml ammonium solution with the weight of 20, 40, 60 and 80 g, and a contact time respectively 30, 60, 120, 180 and 1440 minutes (24 hours). During the adsorption, stirring to optimize adsorp- tion is conducted regularly. The activated carbon used in this research consist of two types are coal based activated carbon and coconut shell activated carbon. Coal activated carbon has a surface area 196.7 m2/g and 643.0 m2/g. While coconut shell activated carbon has a surface area of 59.6 m2/g and 985.9 m2/g. Results of the adsorption process showed that coal activated carbon with a surface area of 643, 0 m2/g have the same capability ammonium adsorption with coconut shell activated carbon with a surface area of 985.9 m2/g. These results showed that a both types of activated carbon can be used optimally for the removal ammonium with percentage of adsorption reaches more than 90%

ECONOMIC FEASIBILITY ANALYSES OF COAL- BASED ACTIVATED CARBON PLANT IN INDONESIA

Technology to make activated carbon from coal has been developed from laboratory to pilot plant scales with capacity of 1 ton/day. The results of previous experiments showed that the quality of coal activated carbon has complied with the standard of quality activated carbon from coconut shell (SNI). In addition, the result of coal utilization process showed that activated carbon can be used for water purification on hatchery, and waste water treatment in textiles and rubber industries. Although the technology and the quality have been reached, but for the production it still needs economic feasibility analysis. Economic feasibility analysis is necessary for coal- based activated carbon plant at commercial scale by giving an indication about economic value of the project. The indicators used in the analysis are Net Present Value (NPV), Return on Investment (ROI), Internal Rate of Return (IRR) and Payback Period. Calculation of financial indicators for the activated carbon project produced Rp 49.17 billion NPV, 50% ROI, 68,25% IRR and 1 year 4 months Payback Period. Based on that calculation, it can be concluded that the coal-based activated carbon plant would be economically feasible under certain operational scenarios. This study is expected to become an economic reference material and can attract inves- tors to construct the commercial plant

COAL DE-ASHING BY SOLVENT EXTRACTION

Coal contains mineral matter that will be left as ash after coal is burned. Coal will be referred to as dirty coal if the ash content of the coal is high. High ash content is not preferred by consumers of coal users especially coal fired power plants, because ash content will produce fly ash and bottom ash that cause environmental problem. The process of ash content reduction by solvent extraction would produce coal with very low ash content (near zero) known as ash free coal (AFC). The study of ash content reduction was conducted by using Peranap coals that were taken from stockpile and mine site. The coals were then washed and separated into coals with low and high ash contents. The high ash content of coals from stockpile (46.02%) and mine site (25.02%) were then extracted using solvent. Three kinds of solvent have been tested, namely 1-methyl naphthalene, 1-1-1-methoxy ethoxy acetic acid and N-methyl 2 pyrolidynon. The results indicate that the ash content of coal derived from the stockpile decreased to 0.06% and coal from the mine site decreased to 0.11% by using 1-methyl naphthalene solution with a ratio of coal and solvent of 1: 6 (weight/weight)

STUDY ON COMBUSTION CHARACTERISTICS OF COAL-BIOMASS FOR CO-FIRING SYSTEM AS A FEEDSTOCK OF COAL GASIFICATION PROCESS

Biomass co-firing is recognised as a crucial technology to aid in the use of fossil fuels, particularly due to its relative ease of implementation. Many studies of the combustion processes associated with co-firing have been conducted elsewhere. This paper discusses the combustion characteristics of coal and torrefied biomasses. Combustion profiles can be used to study certain combustion properties of fuels and fuel blends. The biomass fuels utilized in this study include twig, trunk and weed as the wastes from tea plantation. The results of this work provide data concerning the combustion processes of co-firing determined by simultaneous thermal analysis (STA) methods. Simultaneous thermogravimetric & differential scanning calorimetry/differential thermal analysis (STA, TGA-DSC/DTA) measures both the heat flow (DSC) and the weight changes (TG) in a material as a function of temperature or time in a controlled atmosphere. The results indicate that the mixture of coal and torrefied trunk in the weight ratio of coal-trunk of 25:75 shows the best combustion performance compared to other compositions of coal – torrefied biomass

PENGARUH PENAMBAHAN KATALIS TiO2 TERHADAP SIFAT KIMIA PERMUKAAN KOMPOSIT KARBON AKTIF UNTUK PENYERAPAN GAS SO2

Karbon aktif dan TiO2 mereduksi SO2 melalui proses adsorpsi dan fotokatalitik. Kedua senyawa ini memiliki efektivitas adsorpsi rendah. Untuk meningkatkan aktivitas adsorpsi dilakukan kombinasi teknik adsorben dan fotokatalitik sehingga adsorpsi dapat optimal. Kombinasi dilakukan dengan membuat komposit karbon aktif/TiO2. Batubara dan semi-kokas dicampur dengan perbandingan 7:3 kemudian TiO2 ditambahkan dengan konsentrasi 1, 3, 6, 9 dan 15%. Karbon aktif/ TiO2 dikarbonisasi pada suhu 600 °C selama 1 jam dan diaktivasi pada suhu 900 °C selama 1 dan 2 jam di bawah aliran gas nitrogen. Hasil analisis fourier-transform infrared (FTIR) spectroscopy menunjukkan intensitas serapan gugus fungsi C=O naik sebesar 49,5% pada karbon aktif/TiO2 6% selama 1 jam dan 33,2% pada karbon aktif/TiO2 3% selama 2 jam. Gugus fungsi basa C=O mereduksi gas SO2 yang bersifat asam. Hasil X-ray diffraction (XRD) ditemukan kristal TiO2 anatas dan rutil. Koeksistensi kristal anatas dan rutil lebih efektif daripada anatas dan rutil fase tunggal. Hasil penelitian ini menunjukkan bahwa karbon aktif/TiO2 meningkatkan aktivitas gugus fungsi permukaan karbon aktif dan membentuk kristal TiO2 anatas dan rutil secara bersama