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"Torrefaction has been increasing in popularity as a viable pretreatment process to produce a coal like biomass characteristic. One such biomass that could be used is Palm Kernel Shell (PKS) waste from the production of Crude Palm Oil (CPO) as Indonesia is one of the highest CPO producing country in the world. The potential use of this alternative fuel can be implemented in several industries to reduce CO2 emissions. One such industry that produce a high number of CO2 emission is the cement industry. The result of the research will be the efficiency of torrefaction process, the potential CO2eq avoided by using co-firing and the cost of avoidance of co-firing in cement kiln. It was found that the torrefaction process using PKS waste have an energy efficiency of 67,5% and an energy yield of 79,8%. The potential CO2eq avoided by using co-firing in Indarung V plant is 187.433-933.634-ton CO2eq /year depending on co-firing ratio, The torrefied biomass commercial price is in the range of 231 US$/ton -263 US$/ton and 50% Co-firing ratio gives the best performances, lowest cost avoidance value of 43,20 US$/ton CO2eq and reduction of 33% of the total CO2eq emission from Clinker Production.

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Torefaksi telah semakin populer sebagai proses pretreatment yang layak untuk menghasilkan biomassa seperti karakteristik batubara. Salah satu biomassa yang dapat dimanfaatkan adalah limbah Cangkang Sawit (PKS) dari produksi Minyak Sawit Mentah (CPO) karena Indonesia merupakan salah satu negara penghasil CPO tertinggi di dunia. Potensi penggunaan bahan bakar alternatif ini dapat diterapkan di beberapa industri untuk mengurangi emisi CO2. Salah satu industri yang menghasilkan emisi CO2 yang tinggi adalah industri semen. Hasil dari penelitian ini adalah efisiensi proses torefaksi, potensi CO2eq yang dapat dihindari dengan penggunaan co-firing dan biaya penghindaran co-firing pada cement kiln. Didapatkan bahwa proses torrefaksi menggunakan limbah PKS memiliki efisiensi energi sebesar 67,5% dan yield energi sebesar 79,8%. Potensi CO2eq yang dapat dihindari dengan menggunakan co-firing di pabrik Indarung V adalah 187.433-933.634-ton CO2eq/tahun tergantung pada rasio co-firing, Harga komersial PKS torefaksi berada pada kisaran 231 US$/ton - 263 US$/ton dan 50% Co-firing rasio memberikan kinerja terbaik, nilai penghindaran biaya terendah sebesar 43,20 US$/ton CO2eq dan pengurangan sebesar 33% dari total emisi CO2eq dari Produksi Klinker."

"ABSTRAKPada penelitian ini dilakukan analisis teknis, lingkungan, dan ekonomi pada sistem pembangkit listrik batu bara dengan teknologi chemical looping dan metanol. Tujuan dari penelitian ini adalah mendapatkan efisiensi carbon capture, efisiensi sistem, faktor emisi, dan biaya produksi hidrogen dan metanol dari teknologi hidrogen yang berbeda. Simulasi dilakukan dengan perangkat Aspen Plus®. Divariasikan steam-to-carbon (S/C) dan Fe2O3-to-coal (OC/fuel) pada Coal Direct Chemical Looping (CDCL) untuk mendapatkan efisiensi carbon capture. CO2 dimanfaatkan menjadi metanol dengan ko-reaktan hidrogen dari Steam Methane Reforming (SMR) atau Solid Oxide Electrolysis Cell (SOEC). SOEC mendapat suplai listrik dari PV yang dilengkapi baterai. Hasil analisis memperlihatkan bahwa efisiensi carbon capture sebesar 93-99% didapat dengan peningkatan S/C. Faktor emisi pembangkit menurun dengan kenaikan S/C. Nilai optimum didapatkan pada S/C=0,93. Efisiensi energi sistem keseluruhan lebih tinggi dengan SOEC dibandingkan SMR, dengan nilai efisiensi 66,95% berbanding 50,30%. Emisi gas rumah kaca (GRK) sistem Coal to Power & Methanol dengan SOEC didapatkan lebih rendah dari SMR dengan nilai 0,45 terhadap 2,53 kgCO2eq/kgMeOH. Investasi PV dan elektroliser pada tahun 2019 masih sangat tinggi sehingga biaya produksi hidrogen SOEC lebih tinggi dibanding SMR. Biaya produksi hidrogen SOEC 5,7 $/kg dibanding SMR 1,7 $/kg menyebabkan biaya produksi metanol SMR 393 $/ton dan SOEC 1226 $/ton.

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ABSTRACT

In this study, a technical, environmental, and economic analysis were carried on coal power generation system with chemical looping and methanol. The purpose of this study is to obtain carbon capture efficiency, system efficiency, emission factors, and cost of producing hydrogen and methanol from different hydrogen technologies. Simulations were carried with Aspen Plus®. Varying steam-to-carbon (S/C) and Fe2O3-to-coal (OC/fuel) in Coal Direct Chemical Looping (CDCL) to obtain carbon capture efficiency. CO2 is fed to methanol synthesis with hydrogen as co-reactants from Steam Methane Reforming (SMR) or Solid Oxide Electrolysis Cell (SOEC). SOEC electricity supplied from PV that is equipped with batteries. The result shows that carbon capture efficiency of 93-99% is obtained by increasing S/C. Power Plant emission factors decrease with increase in S/C. The optimum value is obtained at S/C = 0,93. The overall system energy efficiency is higher with SOEC than SMR, with a value of 66,95% compared to 50,30%. Greenhouse gas (GHG) emissions from Coal to Power & Methanol system with SOEC are lower than with SMR with a value of 0,45 to 2,53 kgCO2eq/kg MeOH. PV and electrolyzer investment in 2019 is still very high resulting cost of producing hydrogen with SOEC is higher than SMR. The value for hydrogen with SOEC is 5,7 $/kg compared to SMR 1,7 $/kg causing the cost of producing methanol with SMR 393 $/tonne and SOEC 1226 $/tonne."

"ABSTRAK

Penelitian mengenai bahan bakar nabati terus berkembang sampai saat ini.

Perkembangan ini secara spesifik sudah ditandai dengan pengembangan generasi

kedua biofuel yakni renewable diesel. Renewable diesel merupakan hidrokarbon

turunan dari minyak nabati yang mengalami proses deoksigenasi. Pada penelitian

ini, langkah awal yang dilakukan adalah melakukan preparasi katalis nanopartikel

NiMo/Al2O3 menggunakan metode simple heating. Hasil karakterisasi dari katalis

ini adalah ukuran partikel sebesar 93,43 nm dan 59,07 nm. Katalis nanopartikel

NiMo/Al2O3 kemudian digunakan untuk reaksi deoksigenasi dengan senyawa

model asam oleat yang dikondisikan pada tekanan 9 bar dan 15 bar, suhu operasi

400°C, dan kecepatan pengadukan 800 rpm. Konversi tertinggi dari minyak

deoksigenasi ini mampu mencapai 68,51 % sedangkan selektivitasnya sebesar

57,56 %.

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ABSTRACT

Research on bio-fuels continues to grow today. This development has been

specifically characterized by the development of second generation biofuels which

is named renewable diesel. Renewable diesel is hydrocarbons derived from

vegetable oils undergo a process of deoxygenation. In this study, the first step is to

make the catalyst nanoparticle of NiMo/Al2O3 with simple heating?s method. The

results of this characterization of the catalyst particle size are capable of reaching

the 93,43 nm and 59,07 nm. Nanoparticles catalyst of NiMo/Al2O3 then used for

the deoxygenation reaction with oleic acid which is conditioned at a pressure of 9

bar and 15 bar, operating temperature of 400 °C, and stirring speed of 800 rpm.

The highest conversion of oil deoxygenation is able to achieve 68,51% while the

selectivity of 57,56%."

"Semen merupakan bahan utama untuk pembuatan beton sangat penting perannya dalam kegiatan industri konstruksi sehingga diantara beton dan semen merupakan dua hal yang tidak dapat dipisahkan, dengan kata lain dimana ada pekerjaan beton disitu harus ada semen demikian pula sebaliknya"

"A cement plant that produces 8,300 tons per day releases 265,000 Nm3/h of flue gas at 360°C from its Suspension Preheater (SP) and 400,000 Nm3/h of hot air at 310°C from its air quenching cooler (AQC). It is imperative to recover the waste heat emitted by the plant for power generation, i.e., Waste Heat Recovery Power Generation (WHRPG). This paper aims to optimize waste heat recovery from the cement plant using Response Surface Methodology (RSM), for which an Organic Rankine Cycle (ORC) is applied for electric power generation. The working fluid of an ORC power generation system was selected among candidates of organic working fluids (i.e., isobutane, isopentane, benzene, and toluene) by using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), a Multi-Criteria Decision Analysis (MCDA) method. The ORC power generation system configuration and the corresponding operating conditions employing the selected working fluid (i.e., pressures and temperatures) are optimized by applying RSM. Based on TOPSIS evaluation and considering factors of health, safety, environment impacts, cost, and power generated, isopentane was selected as the working fluid for the ORC WHRPG, which was configured to consist of a boiler, two expansion turbines, a reheater, and a recuperator. Implementation of RSM attained optimum operating conditions of high pressure turbine, low pressure turbine, and condenser at 11.3 bar-a saturated vapor, 4.3 bar-a and 184°C, and 1.8 bar-a, respectively. Finally, the gross electric power generated of 5.7 MW at 12.5 percent of energy conversion efficiency is generated by the pertinent ORC WHRPG."

"Diantara jenis pembangkit listrik yang ada di Indonesia, Pembangkit Listrik Tenaga Uap (PLTU) merupakan sumber energi listrik terpenting dengan porsi 65,6% dari total produksi listrik nasional. Namun, emisi yang dihasilkan PLTU berperan sebagai penyumbang terbesar dalam menghasilkan gas rumah kaca. Teknologi co-firing merupakan metode yang dianggap efektif untuk mengurangi emisi karbon dan berbagai polutan lainnya dengan menggunakan campuran sekam padi dan batu bara sebagai bahan bakar PLTU. Namun demikian, metode tersebut berdampak pada penurunan kapasitas daya maksimum dan efisiensi pembangkit, terutama pada efisiensi boiler. Pada penggunaan sekam padi sebanyak 25% terhadap batubara, diperoleh penurunan daya mampu pembangkit hingga 2,59% dengan nilai efisiensi boiler sebesar 83,79% atau 1,32% lebih rendah jika menggunakan murni batubara; yang menghasilkan biaya rugi-rugi energi boiler sebesar 42,21 miliar rupiah. Lebih lanjut, penggunaan sekam padi dengan persentase yang lebih besar menghasilkan biaya rugi-rugi energi boiler semakin meningkat dibandingkan hanya dengan menggunakan batubara.

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Among the existing types of power plants in Indonesia, coal fired power plants (CFPP) are the most important source of electrical energy with a portion of 65.6% of the total national electricity production. However, the emissions produced by CFPP play a role as the largest contributor in producing greenhouse gases. The co-firing technology is an effective method for reducing carbon emissions and other pollutants by using a mixture of rice husks and coal as CFPP fuel. Nevertheless, this method has an impact on reducing maximum power capacity and efficiency of the power plant, especially the efficiency of the boiler. When using 25% rice husk for coal, there is a decrease in the maximum capable power up to 2.59% with a boiler efficiency value of 83.79%, or 1.32% lower if using pure coal; as well as the cost of boiler energy losses of 42.21 billion rupiah. When using 25% rice husk for coal, there is a decrease in the maximum capable power up to 2.59% with a boiler efficiency value of 83.79%, or 1.32% lower if using pure coal; as well as the cost of boiler energy losses of 42.21 billion rupiah. Furthermore, the increasing use of rice husks in co-firing makes the cost of boiler energy losses greater than using only coal."

"Langkah konservasi energi penelitian ini mengupayakan peningkatan efisiensi pada teknik co-firing yang sudah umum dilakukan di Indonesia melalui sistem pengering biomassa. Percobaan dilakukan melalui pengujian salah satu pembangkit PLTU di area Jawa Barat dengan daya terpasang 3 x 350 MW yang sudah menerapkan co-firing sejak tahun 2021. Sistem pengering dipilih menggunakan jenis Rotary Drum Dryer dengan media pemanas berupa limbah panas gas buang exit boiler yang diambil setelah IDF #1 dengan tekanan ± 20 pa dan temperature 150 oC. Tekanan keluaran IDF #1 sangat rendah membutuhkan energi tambahan besar centrifugal fan dalam menyalurkan flue gas melalui pipa sepanjang ± 500 m sampai menuju lokasi dryer di area coal yard, dekat penyimpanan biomassa dan conveyor batu bara penyuplai bahan bakar ke sistem pembangkit. Biomassa disupplai dari pengusaha lokal sekitar lokasi pembangkit antara lain terdiri dari 90% sawdust dan 10% sekam padi. Memiliki kandungan rata-rata moisture campuran ( 44,57% dan rata-rata calorific value campuran ( 2.673,72 Kcal/Kg. Kapasitas pengering disesuaikan dengan kemampuan supplai biomassa sebesar 200 t/day. Pengujian dilakukan menggunakan simulasi pengering rotary dryer pada Aspen Plus dengan memvariasikan flow inlet biomass 8, 9 dan 10 t/h, flue gas flow 70, 80 dan 90 t/h serta residence time 15, 20 dan 25 menit. Moisture produk dry biomass terendah diperoleh 6,54% pada pengujian flow inlet biomass 8 t/h, flue gas flow 90 t/h dan residence time 25 menit. Hasil simulasi Aspen kemudian dibandingkan pada 5 kriteria penilaian kelayakan investasi yaitu NPV, IRR, Payback Period (PBP), Benefit and Cost (B/C) Ratio dan ROI. Hasilnya walaupun moisture produk dry biomass diperoleh lebih besar 10,9%, namun nilai NPV, IRR dan PBP, masing-masing sebesar Rp. 116.445.284.041,63, 150,32% dan 0,67 tahun, diperoleh sebagai yang terbaik pada pengujian flow inlet biomass 10 t/h, flue gas flow 90 t/h dan residence time 25 menit. Hal ini karena flow rate produk dry biomass lebih besar sehingga mampu membangkitkan selisih energy output yang lebih besar pula pada generator pembangkit. Sedangkan hasil terbaik B/C Ratio dan ROI, masing-masing sebesar 4,14 dan 314,12%, didapatkan saat pengujian flow inlet biomass 10 t/h, flue gas flow 80 t/h dan residence time 25 menit, hal ini karena energi tambahan untuk mendorong flue gas lebih kecil sehingga mempengaruhi B/C Ratio dan ROI. Penurunan energy output dan operational duration harus sedapat mungkin dihindari karena dampaknya sangat significant dalam menurunkan nilai 5 kriteria penilaian investasi. Validasi desain sistem pengering pada Aspen juga dilakukan untuk mengetahui akurasi.

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This energy-conservation research aims to improve the efficiency of the cofiring process, which is widely utilized in Indonesia, using a biomass drying system. The experiment was conducted on a steam-coal power station in the West Java area with an installed power of 3 x 350 MW, which has been using cofiring since 2021. The drying method was selected utilizing a Rotary Drum Dryer type with a heating medium from waste heat of exhaust boiler flue gas obtained after IDF # 1, with pressure ± 20 pa and temperature 150 oC. The output pressure of IDF #1 is very low, requiring large additional energy from the centrifugal fan to flow the flue gas through a pipe measuring ± 500 m long to the dryer location in the coal yard area, near the biomass storage and coal conveyor that supplies fuel to the boiler system. Biomass is supplied from local suppliers around power plant location, consisting of 90% sawdust and 10% rice husks. It has an average mixed moisture content  44.57% and an average mixed calorific value  2,673.72 Kcal/Kg. The dryer capacity is adjusted to the biomass supply capability of 200 t/day. Experiments were carried out using a rotary dryer simulation on Aspen Plus by varying biomass inlet flow of 8, 9 and 10 t/h, flue gas flow of 70, 80 and 90 t/h and residence time of 15, 20 and 25 minutes. The lowest dry   biomass product moisture was obtained at 6.54% in the biomass inlet flow test of 8 t/h, flue gas flow of 90 t/h and residence time of 25 minutes. The results from Aspen simulation then compared with 5 investment assessment criteria: NPV, IRR, Payback Period (PBP), Benefit and Cost (B/C) Ratio and ROI. Even though the moisture content of the dry   biomass product was 10.9%, which was higher than the smallest value, the biomass inlet flow test yielded the best NPV, IRR, and PBP values, including Rp. 116,445,284,041.63 for NPV, 150.32% for IRR, and 0.67 years for PBP, with a biomass inlet flow test of 10 t/h, a flue gas flow of 90 t/h, and a residence time of 25 minutes. This is because the flow rate of the dry   biomass product is greater, so it can generate a larger energy output in the power plant generator. Meanwhile, the best B/C Ratio and ROI findings, including 4.14 and 314.12%, were obtained by testing the biomass inlet flow of 10 t/h, flue gas flow of 80 t/h, and residence period of 25 minutes, this is because the additional energy to push the flue gas is smaller, thus affecting the B/C Ratio and ROI. Decreasing energy output and operational duration must be avoided wherever possible because the impact is very significant in reducing the value of the 5 investment assessment criteria. Validation of the drying system design for Aspen was also carried out to determine accuracy."