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Papers by ika monika

AIP conference proceedings, 2024

Rudarsko-geološko-naftni zbornik, 2024

Palm kernel shells (PKS) were washed with water and glacial acetic acid (CH 3 COOH) gradually to ... more Palm kernel shells (PKS) were washed with water and glacial acetic acid (CH 3 COOH) gradually to prepare them for cofiring with coal. They were then torrefied at 450ºC for one hour. Washing was done to reduce the concentration of ash and alkaline oxides, which would reduce the chance of slagging and fouling. The research was conducted considering that information about washing the PKS with acetic acid and then having them torrefied is very limited and unclear. The results showed that washed and torrefied PKS had better characteristics than those of raw PKS or PKS washed with water. PKS that is washed with acid, torrefied and then blended with coal has low slagging and medium fouling tendencies. However, based on ash fusion temperature, the inclination towards slagging and fouling is high under reducing conditions and medium under oxidation conditions.

IOP conference series, May 1, 2021

Co-combustion of biomass and coal in coal fired power plant could reduce CO2 emissions and utiliz... more Co-combustion of biomass and coal in coal fired power plant could reduce CO2 emissions and utilize renewable energy resources. To understand the co-combustion characteristics of biomass and coal blends, thermogravimetry-differential scanning calorimetry (TG-DSC) analysis, as well as proximate, ultimate and heating value have been conducted. TG-DSC measures both weight changes (TG) and heat flow (DSC) in a material as a function of temperature or time in a controlled atmosphere. The combustion profiles can be used to study some combustion properties of fuels and fuel blends. The biomass that used in this study was sawdust in its origin and torrefied sawdust which blend with a low rank coal. The composition of the biomass and coal were 1:3; 1:1 and 3:1 in weight ratio. Results indicated that the blend of coal and torrefied sawdust in weight ratio of 1:3 was the best combustion performance compared to the other composition, indicated by the highest of ignition temperature (Tig), maximum combustion rate (Rmax) and heating value.

Research Square (Research Square), May 20, 2024

Functional groups on the surface chemical and pore structure are the main properties in the perfo... more Functional groups on the surface chemical and pore structure are the main properties in the performance of activated carbon adsorption. Coal-based activated carbon product is used as a precursor to clarify that the oxygen-blowing into precursor structure can form new site oxygencontaining on the surface. Oxygen functional groups are veri ed through calcination under a nitrogen atmosphere. The process of oxygen-blowing is conducted at different temperatures of 100, 200, 300, 400, and 500°C and calcination at 900°C under a nitrogen atmosphere. The oxygen-containing tended to increase at a temperature of 500°C and encountered the decomposition of functional groups from the hydroxyl to carboxyl groups. The high temperature of 900°C in the calcination process formed new sites of nitrogen-carboxyl groups bonded, which improved micropore volume and CO 2 adsorptionbreakthrough time exhibited the more extended time duration for the calcination samples. This study proved that oxygen-blowing and calcination on coal-based activated carbon products can generate the enhancement of functional groups and pore structure. The increase in adsorption capacity is relatively minor as the volatile matter of activated carbon is very low.

Plastic waste and organic waste in the form of biomass are possible to produce alternative energy... more Plastic waste and organic waste in the form of biomass are possible to produce alternative energy to drive turbines in power plants by turning them on with coal in the co-firing process. This study has purpose analyzing the behavior of coal combustion with a mixture of EFB and plastic compared to the pure coal using the TGA-DSC method. Test were carried out under atmospheric conditions. Addition of biomass in mixture lower the ignition temperature (Tig) of coal. The sample with lowest Tig is C1 (Coal + EFB) with value of 257.8°C. Mixture with biomass decreasing the reactivity of coal with value Tmax is increase, C2 (Coal + EFB + PET bottle) has highest Tmax with value of 423.1°C. C2 also has highest Tbo with value of 622.5°C. From Tmax and Tbo, it showed that addition of biomass decreases the self-burning tendency and prolong the combustion.

Prosiding Teknik Pertambangan; Teknik Pertambangan (Gel 2 Th Akad 2014-2015); 152-158, Aug 13, 2015

Limbah cair merupakan hasil dari suaru proses industri yang sifatnya dapat merusak lingkungan kar... more Limbah cair merupakan hasil dari suaru proses industri yang sifatnya dapat merusak lingkungan karena limbah tersebut mengandung berbagai kontaminan yang tidak dijinkan keberadaannya apabila ada pada konsentrasi tinggi. Limbah cair di PT INDO-RAMA Syhnthetic tbk Purwakarta merupakan limbah hasil buangan poliyaster yang mengandung unsur etilen glikol dan asiteldehid (senyawa organik yang berbahaya dan beracun) sehingga kandungan COD ( Chemical Oxygen Demand) nya tinggi yaitu sekitar 2000-3500 ppm.. Karbon aktif yang digunakan adalah karbon aktif batubara dengan bilangan iodin 304mg/gr, karbon aktif tempurung kelapa bilangan iodin 791 mg/gr dan karbon aktif tempurung kelapa dengan bilangan iodin 104 mg/gr. Proses adsorpsi dilakukan dengan waktu kontak yang berbeda-beda yaitu pada waktu kontak 30 menit, 60 menit, 120 menit, 240 menit dan 24 jam dengan komposisi karbon aktif yaitu, 5gram, 10gram dan 20 gram . Analisis COD sesuai dengan SNI 06-6989.15.2004. Selain analisis COD juga dilakukan analisis terhadap pH sebelum penambahan karbon aktif dan setelah penambahan karbon aktif sesuai SNI 06-6989.11-2004. Hasil penelitian menunjukkan bahwa persentase penyerapan optimal terjadi pada waktu kontak 120 menit dengan komposisi karbon aktif 5 gram, jenis karbon aktif batubara dengan persentase penyerapan 69.3%. Sedangkan untuk karbon aktif tempurung kelapa komersil penyerapannya relatif stabil dan tidak menunjukkan penyerapan yang tinggi. Sedangkan untuk karbon aktif tempurung kelapa dengan bilangan Iodin 791 relatif menunjukkan penurunan COD yang signifikan dengan waktu kontak dan penambahan karbon aktif tertentu. Karbon aktif relatif tidak memiliki pengaruh terhadap kenaikan atau penurunan pH.

Prosiding Teknik Pertambangan, Aug 7, 2017

Coal desulfurization is a process for of decreasing of the sulfur content in coal. The process is... more Coal desulfurization is a process for of decreasing of the sulfur content in coal. The process is carried out on gas of coal gasification, because the sulfur gas in coal gas can be cause corrosive and harmful health. One method of gas desulfurization is adsorption system by using activated carbon. The activated carbon for gas desulfurization should have Iodine number of ≥ 350 mg / gr with a functional group-COC-. The absorption mechanism is the sulfur gas enters the pores of the activated carbon surface and binds to the-COC-bond. Preparation of activated carbon in this research was was derived from low rank coal by using chemical activation method with the HNO3 45% as activating agent, coal sample ratio : activating agent of 1:1, contact time 120 minutes and carboniation temperature at 700 o C. The research was conducted by variation of coal sample ratio : activating agent of 1: 1, 1: 2 and 1: 3, by variation of residence time of 30, 60 and 120 minutes, and carbonization temperature by variation of 600, 700 and 800 o C. Characterization of activated carbon is iodine number analysis, that is analysis to know the absorption of activated carbon and FTIR to know activated carbon functional group. The results showed that the optimal activated carbon for gas desulfurization of coal gas gasification is an activated carbon with the sample ratio : activating agent of 1: 3, contact time 60 minutes and carbonization temperature at 800 o C and functional group with OH, C = C And C = O.

Prosiding Teknik Pertambangan, Aug 11, 2016

ANG technology generally uses materials or carbon materials known as active carbon. Adsorbed Natu... more ANG technology generally uses materials or carbon materials known as active carbon. Adsorbed Natural Gas (ANG) is one technique of natural gas storage in porous solid media. The solids that are used in the form of carbon materials with certain specifications so that it can absorb and store methane gas at room temperature and pressure state relative (low 93.5 to 4.0 MPa). ANG technology is the best storage technology for methane gas because the gas can be stored at room temperature and atmospheric pressure. Therefore, to improve the adsorption capability of the methane gas, in addition to the choice of raw materials also need to learn the activation method. In order to improve the quality of activated carbon to the sub-bituminous coal C type with chemical activation by mixing semikokas and the activation ingredients with ratio of 1: 3, that is 10 gr semikokas 30 gr activativation ingredients and testing of iodine numbers which gained the highest yield at a temperature of 800 o C for 60 minutes at 1197.6 mg/gr. Coal can be used not only as fuel but can also absorb gases at ANG so as to provide added value to minerals, especially coal. Coal activated carbon with iodine 656 mg/gr has a surface area of 491 m 2 / g. With This, if the activated carbon has 1197 mg/gr, the surface area of activated carbon can be assumed to 1242,4 m 2 /gr. The ability to absorb and store the methane gas is 99,9 mg/gr.

Prosiding Teknik Pertambangan, Jan 26, 2018

Characteristics of activated carbon that can be used in gold purification is activated carbon hav... more Characteristics of activated carbon that can be used in gold purification is activated carbon having an iodine number of 900mg / g-1200mg / g where the higher the iodine number the more it will be and the stronger the adsorption capacity of the activated carbon to gold, aromatic function of the aromatic enough to determine the ability of the activated carbon absorption itself. Preparation of activated carbon for gold ore purification with low rank coal raw material, done by chemical activation method and also physics, where activation of chemical with activating agent of H3PO4 with variation of concentration 1, 1.5, 2, 2.5M with soaking time for 8 hours, which is then reactivated physically by heating and inert gas N2 with temperature variations 600, 700, 8000C, for heating time also varied at 1, 2, 3 hours. Characteristic of activated carbon is iodine number analysis to know the absorption of activated carbon and FTIR to know functional group of activated carbon. The results showed that the optimal activated carbon used for gold ore purification was activated carbon made with concentration of 2 M sample with temperature 800oC for 3 hours having functional group with O-H, C = C and C = O bonds.

Hidrotermal (HT) merupakan proses untuk meningkatkan kualitas batubara peringkat rendah melalui p... more Hidrotermal (HT) merupakan proses untuk meningkatkan kualitas batubara peringkat rendah melalui penurunan kadar air pada suhu dan tekanan relatif tinggi (suhu 330°C dan tekanan ±120 atm). Untuk mengetahui pengaruh proses HT terhadap komposisi dan titik leleh abu serta kecenderungan terhadap terjadinya slagging dan fouling pada boiler di pembangkit listrik tenaga uap (PLTU), maka dilakukan penelitian dengan menggunakan percontoh batubara yang berasal dari Samarinda, Tanjung dan Lahat. Hasil penelitian menunjukkan bahwa kadar oksida-oksida alkali seperti CaO, MgO, Na 2 O dan K 2 O mengalami penurunan. Kadar CaO batubara Samarinda sebelum proses HT 3,74% turun menjadi 2,24% setelah proses HT, sedangkan batubara Tanjung dari 1,59 menjadi 0,30% dan batubara Lahat dari 7,43 menjadi 6,68%. Kadar MgO dari 2,38 menjadi 0,57% untuk batubara Samarinda dan batubara Tanjung dari 7,13 menjadi 3,49% sedangkan batubara Lahat dari 4,06 menjadi 2,50%. Kadar Na 2 O batubara Samarinda dari 0,79% sediki...

Technology to make activated carbon from coal has been developed from laboratory to pilot plant s... more 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 pro...

The research of lubricant waste recycling by means of low rank coal as absorbent is one of the wa... more The research of lubricant waste recycling by means of low rank coal as absorbent is one of the ways to render efficient the oil consumption also to maximize the value of low rank coal. This research is a continuation research with a fixed variable, in which the amount of coal is increased to 20% from the amount of the lubricating oil and the heating time which took 2 hours was variated with the heating temperature variable from 150°C to 350°C, the size of coal granule –8+10, -12+14 and –20+24 mesh. The research output shows that the optimum temperature of the lubricating oil recycling by means of coal as absorbent is reached in the temperature of 300°C for the coal with the size –12+14 mesh. In this condition Ca content reduce from 1447 to 150 ppm, Zn reduce from 887 to 17,4 ppm, Fe reduce from 47,1 to 43,5 ppm, Ni reduce from 15,4 to 6,2 ppm and Cr and Cu are all absorbed. The coal resulted from the recycling process can be used as a direct fuel with the calorific value between 500...

World Academy of Science, Engineering and Technology, International Journal of Energy and Power Engineering, 2017

Jurnal Teknologi Mineral dan Batubara, 2021

Karbon aktif dan TiO2 mereduksi SO2 melalui proses adsorpsi dan fotokatalitik. Kedua senyawa ini ... more 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 daripad...

Abstract. Research conducted on the coal which is supplied from the company mines coal that is lo... more Abstract. Research conducted on the coal which is supplied from the company mines coal that is located in the area of the District Palaran , Kota Samarinda , Province Kalimantan East . Testing is done with the purpose that the coal which is supplied can be used be carbonriser with views of the influence of time of residence . Carbonriser itself is a carbon enhancer material used in the smelting process for the manufacture of iron or steel . In doing activities carbonization of coal to be used as carbonriser then coal must be in fuel up first using the tool rotary kiln which a capacity of 1 ton / day , with dimensions of length 8 m and a diameter in the 0 , 8 m . The aim of burning it in order to get the value of the carbon tied (FC) of coal must be in the top 80% and substance fly less than 5%. Coal is used in the process of carbonization is coal that has been processed from coal mill which is in the form of downsizing the size of the coal that is using the tool jaw crusher and vi...

Research on the production of activated carbon from coal has been carried out by Research and Dev... more Research on the production of activated carbon from coal has been carried out by Research and Develop- ment Center for Mineral and Coal Technology since 1980 in the laboratory as well as pilot plant scale. Production of activated carbon from coal using rotary kiln and oil burner at the pilot plant of 1 ton/day has been carried out successfully to produce good quality product. To reduce the dependence upon using oil fuel, the oil fuel burner was replaced by coal fueled cyclone burner. Product quality and economic evalua- tion of the production of activated carbon using the burners are described in this paper. The coal used was subbituminous coal from Air Laya, South Sumatera . The coal passing 3 cm screen was carbonized at 500- 600° C for 2 hours to produce good quality char. The variables of activation process observed were con- sisted of particle size of char (+6, -6+12 and -12 +20 mesh) and residence time (1.5, 3 and 6 hours). The results showed that the optimum condition for acti...

. Activated carbon is a material compound that has the ability to absorb (adsorption) of substanc... more . Activated carbon is a material compound that has the ability to absorb (adsorption) of substances that are around it. As a carbon material, activated carbon can be made from various substances with high carbon composition such as coal, seeds, bones, waste pulp, oil palm, wood, and coconut shell. Coconut shell is the main fuel in the activated carbon industry in Indonesia. The purpose of this study was to determine the stability of the cyclone burner temperature, determine the quality of temperature at T1 and temperature at T2, find out the best quality of activated carbon during activation activities, and determine the percentage of ash content of activated carbon. The process of making activated carbon consists of two methods, namely chemical activation and physical activation. The method used in this activity uses physical activation using water vapor. The tool used is a rotary kiln. So far, activated carbon factories operate rotary kilns for heating and activation processes usi...

Indonesian Mining Journal, 2020

Steam drying process of the Low Rank Coals (LRCs) has been conducted to produce coal which is com... more Steam drying process of the Low Rank Coals (LRCs) has been conducted to produce coal which is comparable with the High Rank Coal (HRC). Characterization of the raw and dried coals was carried out through proximate, ultimate, calorific value, Fourier Transform Infrared (FTIR) spectroscopy and Thermo Gravimetry-Differential Thermal Analysis (TG-DTA) to study the combustion behavior of the coals. This study used Indonesian low rank coals coming from Tabang (TKK coal) and Samurangau (SP coal), East Kalimantan. The results indicate that the calorific value of the dried coals increases significantly due to the decrease in moisture content of the coal. The FTIR spectrums show that the methylene-ethylene (RCH3/CH2) and aromaticity-aliphaticity ratios (Rar/al) of the dried coals increased while the ratio of RCO/ar decreased which reflect that the rank of the coals increased equivalent to the high rank coal (bituminous). Meanwhile, the TG-DTA indicates that the ignition temperature (Tig) and ...

Indonesian Mining Journal, 2017

Disease caused by gastrointestinal nematodes (GIN) is one of the main constraints for sheep produ... more Disease caused by gastrointestinal nematodes (GIN) is one of the main constraints for sheep production worldwide. Although adult categories are more resistant to GIN, a temporary loss of acquired immunity is presented around parturition, which results in the so-called "periparturient rise" (PPR) in fecal excretion of GIN eggs. The objective of the present work was to study the dynamic of the PPR and to model the faecal worm egg count (FEC) curve during the periparturient period in Uruguayan Merino sheep. Faecal samples were collected from lambing ewes during 2009 and 2010 parturitions. FEC and infective larvae cultures of each sampling were recorded. A total of 2,121 records from 748 ewes, the progeny of 107 sires, were used in the statistical analysis. FEC data were normalized using two logarithmic transformations: Log FEC = Log e (FEC + 100) and Log FEC_st (Log FEC with the variance standardized within contemporary group). Three functions were compared to shape the PPR curve. Haemonchus spp. was the most prevalent parasite. Log FEC_st was the selected response variable of the model, for its better adjustment to a normal distribution and a more homogeneous residual variance. The fixed regression model with Legendre polynomials was the selected one, based on the selection model criteria (Akaike & Schwarz Bayesian Information Criteria). The highest egg output was observed between two and four weeks post-lambing. In conclusion, the PPR observed in Uruguayan Merino lambing ewes had the maximum egg output matched with the milk production peak.