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Pabrik etil asetat dirancang dengan kapasitas 17.000 ton/tahun dan akan didirikan di Kabupaten Mojokerto, Jawa Timur. Dasar pemilihan lokasi tersebut adalah dekat dnegan bajan baku, iklim sesuai, dekat dengan jalur transportasi darat, ketersediaan SDM yang memadai dan utilitas. Pabrik ini beroperasi selama 330 hari per tahun. Etil asetat diproduksi menggunakan bahan baku asam asetat dan etanol. Etil asetat dipasarkan didalam Negeri. Dari hasil perhitungan dan analisa ekonomi pabrik etil asetat layak untuk didirikan untuk didirikan dengan Total Capital Investment US$ 31.663.213,86, Laba bersih US$ 15.032.492, Laju Pengendalian Modal (Internal Rate Of Return / IRR) 47,48%, Waktu pengembalian modal (Pay Out Time / POT) 3 tahun, Titik impas (Break Event Point / BEP ) 47,45% dan mampu memperkerjakan 160 orang.

Pabrik Crude Glycerine dari Hasil Samping Biodiesel melalui metode asidifikasi dirancang dengan produksi 78.000 ton/tahun. Pendirian pabrik crude glycerine ini akan didirikan di Srengsem, Kec. Panjang, Kota Bandar Lampung, Lampung. Dasar Pemilihan lokasi ini adalah dari analisa Strength, Weakness, Opportunities, dan Threat (SWOT) dari berbagai aspek, yaitu ketersediaan bahan baku, pemasaran, transportasi, tenaga kerja, utilitas dan iklim. Pabrik ini beroperasi selama 330 hari per tahun. Proses yang digunakan adalah proses asidifikasi dengan menggunakan bahan baku hasil samping biodiesel crude glycerol. Proses ini berlangsung di reaktor Asidifikasi dengan temperatur 78°C serta tekanan 1 atm untuk menghasilkan produk utama yaitu crude glycerine dengan kemurnian 98,5% yang didapatkan setelah dilakukan pemisahan dan pemurnian. Pabrik ini merupakan perusahaan yang berbentuk Perusahaan Terbatas (PT) dengan struktur organisasi “line and staff”, dengan jumlah total tenaga kerja 184 orang. Hasil Analisa Ekonomi pada perancangan pabrik crude glycerine ini menunjukkan bahwa pabrik ini layak didirikan dengan nilai Total Capital Investment sebesar Rp. 1.657.033.034.582 yang diperoleh dari pinjaman bank 40% dan 60% modal sendiri dengan laju pengembalian modal (ROR) sebesar 160%, serta waktu pengembalian modal 7 bulan 23 hari dan nilai Break Event Point (BEP) sebesar 39,37%.

Pabrik Diklorida dirancang dengan kapasitas produksi 37.000 ton/tahun dan akan didirikan di Cilengon, Banten Dasar pemilihan lokasi tersebut adalah dekat dengan penyedia bahan baku, iklim yang sesuai, dekat dengan jalur transportasi darat dan laut, ketersediaan SDM yang memadai dan Utilitas. Pabrik ini beroperasi selama 300 hari per tahun. Etilen Diklorida diproduksi menggunakan bahan baku Etilen, HCl, dan Oksigen. Etilen Diklorida dipasarkan didalam Negeri dan selebihnya akan di ekspor ke luar Negeri. Dari hasil perhitungan dan analisa ekonomi pabrik Propilen glikol Layak untuk didirikan dengan Total Capital Investment Rp. 469.992.878.846, Laba Bersih Rp 390.276.986.663, Laju Pengembalian Modal (Rate of Return / ROR) 83,04 %, Waktu Pengembalian Modal (Pay Out Time / POT) 1 Tahun 11 Bulan, Titik Impas (Break Event Point / BEP) 39,86% dan mampu memperkerjakan 103 orang.

Pabrik Monobasic Kalium Phosphate ini dirancang dengan kapasitas 14.000 ton/tahun dengan menggunakan bahan baku asam fosfat dan kalium hidroksida. Pabrik ini direncanakan berlokasi di Maspion Industrial Estate Gresik Unit 5 dan akan mulai beroperasi pada tahun 2028. Proses yang digunakan dalam pembentukan produk MKP merupakan reaksi eksotermis dengan umpan berupa asam fosfat dan kalium hidroksida. Reaksi ini berlangsung pada suhu 80 ºC dan tekanan 1 atm dengan konversi reaksi sebesar 99%. Reaktor yang digunakan berupa Continuous Stirred Tank Reactor (CSTR) dengan perbandingan mol umpan H3PO4 : KOH adalah 1:1. Kebutuhan listrik untuk keperluan operasional pabrik direncanakan berasal dari PLN dan dari generator sebagai cadangan. Kebutuhan air direncanakan berasal dari Sungai Bengawan Solo. Total kebutuhan air pada kondisi kontinyu adalah 21.237,65 kg/jam. Bentuk badan usaha pabrik MKP ini adalah Perseroan Terbatas (PT) dengan struktur organisasi berupa line and staff dengan total keryawan sebanyak 170 orang. Jadwal kerja beberapa posisi karyawan dibagi menjadi 4 regu shift. Secara keseluruhan, pabrik beroperasi selama 24 jam/hari dan 330 hari/tahun. Berdasarkan perhitungan ekonomi diperoleh nilai rate of return (ROR) sebesar 25%. Waktu pengembalian modal (Pay Out Time) sebesar 4 tahun 6 bulan. Titik Break Even Point (BEP) sebesar 34,52%.

Pabrik Monobasic Kalium Phosphate ini dirancang dengan kapasitas 14.000 ton/tahun dengan menggunakan bahan baku asam fosfat dan kalium hidroksida. Pabrik ini direncanakan berlokasi di Maspion Industrial Estate Gresik Unit 5 dan akan mulai beroperasi pada tahun 2028. Proses yang digunakan dalam pembentukan produk MKP merupakan reaksi eksotermis dengan umpan berupa asam fosfat dan kalium hidroksida. Reaksi ini berlangsung pada suhu 80 ºC dan tekanan 1 atm dengan konversi reaksi sebesar 99%. Reaktor yang digunakan berupa Continuous Stirred Tank Reactor (CSTR) dengan perbandingan mol umpan H3PO4 : KOH adalah 1:1. Kebutuhan listrik untuk keperluan operasional pabrik direncanakan berasal dari PLN dan dari generator sebagai cadangan. Kebutuhan air direncanakan berasal dari Sungai Bengawan Solo. Total kebutuhan air pada kondisi kontinyu adalah 21.237,65 kg/jam. Bentuk badan usaha pabrik MKP ini adalah Perseroan Terbatas (PT) dengan struktur organisasi berupa line and staff dengan total keryawan sebanyak 170 orang. Jadwal kerja beberapa posisi karyawan dibagi menjadi 4 regu shift. Secara keseluruhan, pabrik beroperasi selama 24 jam/hari dan 330 hari/tahun. Berdasarkan perhitungan ekonomi diperoleh nilai rate of return (ROR) sebesar 25%. Waktu pengembalian modal (Pay Out Time) sebesar 4 tahun 6 bulan. Titik Break Even Point (BEP) sebesar 34,52%.

Swirl turbulent flow is intensively used by the industrial equipments such as combustion, separation and heat transfer equipments. The fluid dynamic characteristics of this flow are influenced by the chamber’s geometries and the operating conditions. One of the important operating condition variables which greatly affects the fluid dynamic characteristics is initial tangential intensity (I TI ) or often known as swirl number. This study is aimed to quantify the effect of the initial tangential intensity on the fluid dynamic characteristics in a tangential burner. The method of the study is based on the computational fluid dynamic simulation under the Ansys Fluent CFD engine. The fluid dynamic characteristics were modeled using the standard k- ephsilon turbulent model. The simulation results exhibited that the three dimensional flow structure in a tangential burner is dominated by the tangential flow. The fluid dynamic simulations also showed that the effect of the I TI on the mean turbulence intensity and the mean residence time begin to be significant at the I TI values ≥ 1.1 and ≥ 4.5 respectively, while at low ITI values, its effects on both variables are insignificant. The lowest pressure drop obtained in this study was found on the burner with I TI value of 3.2.

The main process of making biobriquettes is carbonization, namely the formation of biomass into charcoal. Carbonization as charcoal producing tool are being developed today. This is conducted to produce maximum and qualified charcoal. In this research, we have made a prototype of multipurpose tool for carbonization. Besides producing charcoal, we can also utilize its smoke as liquid smoke.This tool is called the Pyrolysis Rotary Carbonisator. This carbonization tool is very effective and easy to use in terms of removing charcoal from the carbonization tool. This design can provide optimal results, that give maximum quantity of charcoal and more evenly heat transfer so carbonization process can be perfect and produce high quality of charcoal as material for bio-briquette. Performance evaluations on the tool proof that it has average efficiency of 90%. Another way of evaluating the work is viewed from the temperature of durian shell, palm shell and coconut shell processing with temperature variation of 200, 250, 300 and 400 oC, we also obtained various maximum heat. From this research, maximum calorie of durian shell charcoal at 400 oC is 5628 kcal/kg, while the palm shell at 300 oC is 7578 kcal / kg and the coconut shell at 400 is 7354 kcal / kg

Pengambilan minyak melati (Jasminum sambac) dengan metode enfleurasi telah dilakukan dengan memvariasikan waktu enfleurasi dan jenis adsorben. Metode enfleurasi dapat mencegah kerusakan minyak atsiri yang diperoleh karena dilakukan pada suhu rendah. Tujuan penelitian untuk melihat jenis adsorben dan berat bunga yang tepat untuk mendapatkan minyak melati optimum. Penelitian dilakukan dengan memvariasikan jenis adsorben (mentega putih dan mentega kuning) dan waktu enfleurasi (6, 10, 12, 16, dan 20 hari). Parameter yang diamati adalah rendemen, komponen minyak, densitas, aroma dan warna minyak yang diperoleh. Hasil penelitian menunjukkan adsorben mentega putih lebih efektif dibandingkan mentega kuning dengan perolehan minyak atsiri tertinggi pada waktu enfleurasi 20 hari dan jumlah bunga 230 gram dengan rendemen 8,69%. Perolehan minyak terendah dengan rendemen 5,21% menggunakan adsorben mentega kuning pada waktu enfleurasi 10 hari dengan berat bunga 115 gram. Komponen-komponen dominan yang terdeteksi dalam minyak diantaranya adalah linalool (8,82%), benzyl acetat (4,58%), hexyl salicylate (4,90%), 1-Phenanthrenecarboxylic acid (5,99%), versalide (3,14%), dan 3-phenyl-propenal (3,29%). Minyak melati yang dihasilkan berwarna kuning muda jernih dengan densitas berkisar antara 0,8821-0,8845 g/mL pada penggunaan adsorben mentega putih dan 0,8175-0,8675 g/mL dengan adsorben mentega kuning. Hasil uji organoleptik menunjukkan rata-rata panelis menyukai aroma dan warna pada minyak melati pada perlakuan waktu enfleurasi 6, 10, dan 12 hari dengan tingkat kesukaan panelis 100% suka.

Limbah cair tahu mengandung gas-gas yang terdekomposisi bahan-bahan organik yang terdapat di dalam air buangan seperti gas nitrogen (N2), oksigen (O2), hidrogen sulfida (H2S), ammonia (NH3), karbondioksida (CO2) dan metana (CH4). Penelitian sebelumnya menemukan bahwa kandungan ammonia pada limbah cair tahu berkisar antara 21,4 mg/L hingga 33,5 mg/L. Angka ini sangatlah tinggi jika dibandingkan dengan standar yang sudah ditetapkan oleh pemerintah yaitu sebesar 8 mg/L. Tujuan dari penelitian ini adalah untuk mengurangi pencemaran lingkungan yang disebabkan oleh ammonia yang berasal dari limbah cair tahu dan mengoptimalkan pemanfaatan limbah cangkang kelapa sawit. Pengurangan kadar ammonia ini dilakukan dengan metode adsorbsi, sedangkan metode analisis kadar ammonia menggunakan spektrofotometri. Arang aktif cangkang kelapa sawit diaktivasi menggunakan larutan H2SO4. Variasi waktu kontak yang digunakan adalah 30, 60, 90 dan 120 menit, sedangkan variasi massa adsorben adalah 2, 4, 6 dan 8gram. Hasil penelitian menunjukkan kondisi optimal untuk proses adsorpsi ammonia adalah 30 menit waktu kontak dengan 4gram jumlah arang aktif. Hasil karakterisasi menunjukkan bahwa arang aktif memenuhi standar kualitas dan cocok untuk mengurangi kadar ammonia dalam limbah cair tahu. Hasil penelitian ini dapat diaplikasikan untuk pemanfaatan limbah cangkang kelapa sawit untuk penurunan konsentrasi ammonia pada limbah cair tahu.

Rice husk valorization to produce silica is believed to involve an eco-friendly process rather than silica production from conventional and fume routes. Nevertheless, the quantitative point of view regarding this is still not widely disclosed. In this study, a simple material and energy input–output analysis (M&E I/O) is employed to compare the environmental impact of the production of 1 tonne of silica from conventional, fume, and biomass thermochemical conversion routes. The scope consideration includes raw material, transportation, utility systems, main production process, and output streams as environmental impact. Results show that conventional and fume routes need 3.86 tonnes of sandstone and biomass thermochemical conversion route needs 6.56 tonnes of rice husk. For conventional and fume routes, energy is supplied from 1194.08 and 1954.99 kg of coal combustion, whereas the biomass thermochemical conversion route uses rice husk as fuel and additional coal of only 238.38 kg. Further, the lowest CO2-equivalent emission of 0.85 tonnes is nominated to the biomass thermochemical conversion route, while conventional and fume routes are 10.09 and 18.62 tonnes, respectively. The produced wastewater from conventional, fume, and biomass thermochemical conversion routes is 27.27, 27.13, and 24.76 tonnes, successively. This study concludes and proves that silica production from rice husk is more eco-friendly and has low environmental impact, but wastewater treatment to meet the effluent standard should be applied.

Finding the cheaper alternative fuels and shortening the rendang cooking time are the potential efforts to reduce the production cost of rendang. This study aims to use low-rank cheap coal to cook beef rendang and to develop a more efficient rendang cooking method. First, the raw coals were carbonized, then the charcoals obtained were crushed and mixed with the filler and binder. After that, the charcoal mixture was molded into briquettes. Furthermore, the carbonized coal briquettes resulted were characterized and used as fuel to cook beef rendang in a semi-closed moveable-grate stove. To get a more efficient cooking time, a modified cooking method was developed. From the research has been obtained that there was almost no significant odor and smoke emissions during the cooking process except at the initial ignition period, which takes between 10-15 minutes. The modified cooking method took time 3 hours to get the dry beef rendang, 1 hour shorter than that of the normal cooking ones. Briquettes consumption for 1 kg of beef rendang cooking,using the modified cooking method, was about 0.75 kg, equivalent to USD 0.18 if 1 kg of briquette is priced USD 0.24. Finally, it can be summarized that carbonized coal briquette is a solid smokeless fuel that is safe and cheap to cook beef rendang.

The acid leaching process is believed to increase the silica extracted from rice husk ash (RHA). This study intended to investigate the influence of acid leaching sequences in RHA extraction on green silica purity and surface area. The sequences were RHA leaching (T1), aged gel leaching (T2), dried product leaching (T3), and without leaching as a control. The T1 sequence has been proven to improve the green silica purity and sur- face area reaching 96.44% and 400.69 m2/g, respectively. For T2 and T3 sequences, the green silica has a much lower surface area and purity compared to T1. The values were 87.69% and 55.49 m2/g for T2 as well as 62.46% and 11.40 m2/g for T3. Without acid leaching, the purity and surface area of green silica significantly reduced to 56.94% and 5.72 m2/g. This study concludes that green silica from T1 sequence has successfully obtained high purity, high surface area, and indicates an amorphous and mesoporous particle. It is suitable to be utilized as an industrial silica gel for moisture adsorber which more sustainable and greener process.

The acid leaching process is believed to increase the silica extracted from rice husk ash (RHA). This study intended to investigate the influence of acid leaching sequences in RHA extraction on green silica purity and surface area. The sequences were RHA leaching (T1), aged gel leaching (T2), dried product leaching (T3), and without leaching as a control. The T1 sequence has been proven to improve the green silica purity and sur- face area reaching 96.44% and 400.69 m2/g, respectively. For T2 and T3 sequences, the green silica has a much lower surface area and purity compared to T1. The values were 87.69% and 55.49 m2/g for T2 as well as 62.46% and 11.40 m2/g for T3. Without acid leaching, the purity and surface area of green silica significantly reduced to 56.94% and 5.72 m2/g. This study concludes that green silica from T1 sequence has successfully obtained high purity, high surface area, and indicates an amorphous and mesoporous particle. It is suitable to be utilized as an industrial silica gel for moisture adsorber which more sustainable and greener process.

Pengambilan minyak melati (Jasminum sambac) dengan metode enfleurasi telah dilakukan dengan memvariasikan waktu enfleurasi dan jenis adsorben. Metode enfleurasi dapat mencegah kerusakan minyak atsiri yang diperoleh karena dilakukan pada suhu rendah. Tujuan penelitian untuk melihat jenis adsorben dan berat bunga yang tepat untuk mendapatkan minyak melati optimum. Penelitian dilakukan dengan memvariasikan jenis adsorben (mentega putih dan mentega kuning) dan waktu enfleurasi (6, 10, 12, 16, dan 20 hari). Parameter yang diamati adalah rendemen, komponen minyak, densitas, aroma dan warna minyak yang diperoleh. Hasil penelitian menunjukkan adsorben mentega putih lebih efektif dibandingkan mentega kuning dengan perolehan minyak atsiri tertinggi pada waktu enfleurasi 20 hari dan jumlah bunga 230 gram dengan rendemen 8,69%. Perolehan minyak terendah dengan rendemen 5,21% menggunakan adsorben mentega kuning pada waktu enfleurasi 10 hari dengan berat bunga 115 gram. Komponen-komponen dominan yang terdeteksi dalam minyak diantaranya adalah linalool (8,82%), benzyl acetat (4,58%), hexyl salicylate (4,90%), 1-Phenanthrenecarboxylic acid (5,99%), versalide (3,14%), dan 3-phenyl-propenal (3,29%). Minyak melati yang dihasilkan berwarna kuning muda jernih dengan densitas berkisar antara 0,8821-0,8845 g/mL pada penggunaan adsorben mentega putih dan 0,8175-0,8675 g/mL dengan adsorben mentega kuning. Hasil uji organoleptik menunjukkan rata-rata panelis menyukai aroma dan warna pada minyak melati pada perlakuan waktu enfleurasi 6, 10, dan 12 hari dengan tingkat kesukaan panelis 100% suka

Abundant availability and large silica content in rice husk black ash (RHBA) make the use of it very interesting to study. Many works only deal with lab-scale rice husk ash extraction while the studies on bench-scale RHBA extraction are still limited. This study, hence, presents the influence of pretreatment, extraction variables, and posttreatment on bench-scale RHBA processing to bio-silica. The pretreatment through acid leaching was carried out using HCl. The extraction was implemented under varying process variables such as alkaline-to-feed ratio (RA/F), extraction duration, and acid precipitation agent. According to this study, the highest extraction yield up to 98% was gained under RA/F 6 g/g and 1-h extraction. The amorphous bio-silica had an asymmetric siloxane bond and white appearance with a purity exceeding 95% and surface area up to 406.98 m2/g. Meanwhile, precipitation under HCl and H2SO4 had little impact on product purity and surface area. This study exhibits that acid leaching is executed to release mineral impurities but is still not sufficient to remove the remaining carbon content in bio-silica. However, the contribution of refining process is able to do so. Moreover, the produced bio-silica is suitable for adsorbent purposes which could adsorb up to 83.5% of 3-monochloropropanediol compound.

Abundant availability and large silica content in rice husk black ash (RHBA) make the use of it very interesting to study. Many works only deal with lab-scale rice husk ash extraction while the studies on bench-scale RHBA extraction are still limited. This study, hence, presents the influence of pretreatment, extraction variables, and posttreatment on bench-scale RHBA processing to bio-silica. The pretreatment through acid leaching was carried out using HCl. The extraction was implemented under varying process variables such as alkaline-to-feed ratio (RA/F), extraction duration, and acid precipitation agent. According to this study, the highest extraction yield up to 98% was gained under RA/F 6 g/g and 1-h extraction. The amorphous bio-silica had an asymmetric siloxane bond and white appearance with a purity exceeding 95% and surface area up to 406.98 m2/g. Meanwhile, precipitation under HCl and H2SO4 had little impact on product purity and surface area. This study exhibits that acid leaching is executed to release mineral impurities but is still not sufficient to remove the remaining carbon content in bio-silica. However, the contribution of refining process is able to do so. Moreover, the produced bio-silica is suitable for adsorbent purposes which could adsorb up to 83.5% of 3-monochloropropanediol compound.

Rice husk combustion in the suspension furnace is not an easy matter. Until now, there are still many obstacles faced in its process as characterized by low combustion conversion. The main cause is the poor air-particle contact as well as the probability of particle elutriation out of the furnace chamber before combustion completely occurs. Thus, in-depth and detailed understanding of air and rice husk cold flow structures in the furnace chamber, as proposed in this study, becomes necessary. The simulation study was conducted using Reynold stress model (RSM) for fluid flow quantification whereas discrete phase model was utilized for particle flow quantification. The simulation results reveal that cylindrical chamber gives a more significant particle residence time rather than rectangular chamber for every similar excess air amount. Besides, providing burner with a tangential air inlet of 90o results in high turbulence, intense swirl phenomenon, and long particle residence time. Moreover, the furnace chamber equipped with a smaller burner diameter and longer burner length together will augment the air-particle contact in the furnace chamber. Despite providing the best condition for the furnace, the design must not forget to consider the economical aspect.

The usage of biomass can reduce vast amounts of fossil resource dependence. Rice husk is attractive due to its calorific value and high silica content in ash. In order to produce amorphous silica in ash, rice husk was combusted with temperatures below 700°C and this can be realized in a suitable furnace type, i.e. suspension furnace. This study began with rice husk ignition test in a fixed bed furnace. The ignition temperature was observed above (428 ± 8)oC. Combustion was then performed in a suspension furnace. Rice husk was semi-continuously fed when it attained the ignition temperature with total air to biomass ratio of 8.5. The mass flowrates of rice husk were set at 9.27, 20.23, 25.20, 31.36, and 42.51 kg/h. The feeding was stopped until it reached 2500 g for the first 4 variations and 500 g for the last variation. From this study, the flaming combustion lasted for 15–30 min and then continued with glowing combustion which plays an important role in the successful conversion to ash. The highest temperatures of combustion were 552–560°C. Besides, the yield of produced ash was 18.94–23.68%-wt with silica content therein of 88.29–89.15%-wt. Ash was acquired in the amorphous silica phase with unburnt carbon content of 5.11–23.27%-wt.

Rice husk combustion in the suspension furnace is not an easy matter. Until now, there are still many obstacles faced in its process as characterized by low combustion conversion. The main cause is the poor air-particle contact as well as the probability of particle elutriation out of the furnace chamber before combustion completely occurs. Thus, in-depth and detailed understanding of air and rice husk cold flow structures in the furnace chamber, as proposed in this study, becomes necessary. The simulation study was conducted using Reynold stress model (RSM) for fluid flow quantification whereas discrete phase model was utilized for particle flow quantification. The simulation results reveal that cylindrical chamber gives a more significant particle residence time rather than rectangular chamber for every similar excess air amount. Besides, providing burner with a tangential air inlet of 90o results in high turbulence, intense swirl phenomenon, and long particle residence time. Moreover, the furnace chamber equipped with a smaller burner diameter and longer burner length together will augment the air-particle contact in the furnace chamber. Despite providing the best condition for the furnace, the design must not forget to consider the economical aspect.

The degree of mixing is one of the main indicators of the combustion performance in a combustion chamber. The higher the degree of mixing, the more intensive the contact/reaction between the air and the fuel, so that the combustion performance is getting better. The degree of mixing in a combustion chamber is indicated quantitatively by several variables such as the velocity profiles, the flow structure and the turbulence intensity. The degree of mixing in a combustion chamber is influenced by the factors of geometries and operating conditions. This study is aimed to determine the effect of the inlet aspect ratio (RIA) to the mixing characteristics in a tangential burner. The investigation methodology used in this study is based on the numerical simulation with the Ansys-Fluent simulation code as a Computational Fluid Dynamics (CFD) engine. The fluid flow modelings are performed with the standard k-Ephsilon turbulent model. From the simulations that at mesh interval size smaller than 7 % of the chamber diameter, the standard k-Ephsilon model is able to match satisfactorily the tendency of the experimental velocity profiles available in the literature. The simulation results also show that the inlet aspect ratio has a significant influence to the mixing characteristics in the tangential burner. Within the RIA value that is tested, the best mixing characteristic is found on the burner with the RIA value of 10. The formation of the tornado tail flow structure is determined by the inlet aspect ratio, the total mass flow rate and the swirl number.

Rice husk valorization to produce silica is believed to involve an eco-friendly process rather than silica production from conventional and fume routes. Nevertheless, the quantitative point of view regarding this is still not widely disclosed. In this study, a simple material and energy input–output analysis (M&E I/O) is employed to compare the environmental impact of the production of 1 tonne of silica from conventional, fume, and biomass thermochemical conversion routes. The scope consideration includes raw material, transportation, utility systems, main production process, and output streams as environmental impact. Results show that conventional and fume routes need 3.86 tonnes of sandstone and biomass thermochemical conversion route needs 6.56 tonnes of rice husk. For conventional and fume routes, energy is supplied from 1194.08 and 1954.99 kg of coal combustion, whereas the biomass thermochemical conversion route uses rice husk as fuel and additional coal of only 238.38 kg. Further, the lowest CO2-equivalent emission of 0.85 tonnes is nominated to the biomass thermochemical conversion route, while conventional and fume routes are 10.09 and 18.62 tonnes, respectively. The produced wastewater from conventional, fume, and biomass thermochemical conversion routes is 27.27, 27.13, and 24.76 tonnes, successively. This study concludes and proves that silica production from rice husk is more eco-friendly and has low environmental impact, but wastewater treatment to meet the effluent standard should be applied.

The usage of biomass can reduce vast amounts of fossil resource dependence. Rice husk is attractive due to its calorific value and high silica content in ash. In order to produce amorphous silica in ash, rice husk was combusted with temperatures below 700°C and this can be realized in a suitable furnace type, i.e. suspension furnace. This study began with rice husk ignition test in a fixed bed furnace. The ignition temperature was observed above (428 ± 8)oC. Combustion was then performed in a suspension furnace. Rice husk was semi-continuously fed when it attained the ignition temperature with total air to biomass ratio of 8.5. The mass flowrates of rice husk were set at 9.27, 20.23, 25.20, 31.36, and 42.51 kg/h. The feeding was stopped until it reached 2500 g for the first 4 variations and 500 g for the last variation. From this study, the flaming combustion lasted for 15–30 min and then continued with glowing combustion which plays an important role in the successful conversion to ash. The highest temperatures of combustion were 552–560°C. Besides, the yield of produced ash was 18.94–23.68%-wt with silica content therein of 88.29–89.15%-wt. Ash was acquired in the amorphous silica phase with unburnt carbon content of 5.11–23.27%-wt.

The perennial crops are potentially used as renewable fuels in the boiler furnace. Due to its specific characteristics, the burner design for this biomass needs to be properly developed. The burner design proposed here is a cylindrical burner having an axial inlet and a pair of tangential injection. This study is aimed to investigate the effect of tangential inlet geometry on the burner performance, through numerical evaluation of fluid dynamics characteristics. The numerical evaluations are conducted using k-Ephsilon turbulence model under Ansys-Fluent software. The simulation results showed that, at certain orientation angles of tangential inlet, there are back flows from furnace to the internal burner. This phenomenon is responsible to the flame stability in the burner. The turbulence intensity and convective heat transfer coefficient are also influenced by the tangential inlet orientation angle. For same cross sectional area, the rectangular tangential inlet shape generated deeper backflow penetration and higher turbulence intensity than that was done by the circular ones. One of the rectangular shape shortcomings to the circular ones is to produce the higher static pressure, which correlate to the higher burner operating cost. This investigation study concluded that the burner with rectangular tangential inlet shape and orientation angle of 200 potentially produces the best burner performance.

The perennial crops are potentially used as renewable fuels in the boiler furnace. Due to its specific characteristics, the burner design for this biomass needs to be properly developed. The burner design proposed here is a cylindrical burner having an axial inlet and a pair of tangential injection. This study is aimed to investigate the effect of tangential inlet geometry on the burner performance, through numerical evaluation of fluid dynamics characteristics. The numerical evaluations are conducted using k-Ephsilon turbulence model under Ansys-Fluent software. The simulation results showed that, at certain orientation angles of tangential inlet, there are back flows from furnace to the internal burner. This phenomenon is responsible to the flame stability in the burner. The turbulence intensity and convective heat transfer coefficient are also influenced by the tangential inlet orientation angle. For same cross sectional area, the rectangular tangential inlet shape generated deeper backflow penetration and higher turbulence intensity than that was done by the circular ones. One of the rectangular shape shortcomings to the circular ones is to produce the higher static pressure, which correlate to the higher burner operating cost. This investigation study concluded that the burner with rectangular tangential inlet shape and orientation angle of 200 potentially produces the best burner performance.

A combination of the experimental and numerical methods was used to investigate the fluid flow behaviors in a proposed cyclone burner. Recirculation flow and pressure drop, two of the important fluid flow behaviors that affect the burner's performance, have been studied here. Experimentally, the recirculation flow phenomenon in the burner was observed through paper slices dynamic in a transparent burner, and pressure drop was measured using a tube manometer. Meanwhile numerically, the fluid flow behaviors were simulated using the standard k-Ephsilon turbulence model, under Ansys-Fluent software. The simulation results showed that, at a certain value of inlet aspect ratio (RIA) and initial tangential intensity (IIT), especially for high IIT, the recirculation flow phenomenon was clearly observed in the center of the burner cylinder which closely resembles a tornado-tail. The indication of existence recirculation flow was also found from the experiment results. The study also exhibited that the results of simulated static pressure drop were closely approaching the experiment results, particularly for IIT values  4.3. The mean deviation of static pressure between the simulation and the experiment results, for a varied range of RIA and IIT, was about 15%. From the results above, it was obvious that fluid flow behaviors (recirculation flow and static pressure) in the proposed cyclone burner are greatly influenced by the RIA and IIT values, where the IIT effect was more significant compared to the RIA. This study also suggests that, the standard k-Ephsilon turbulence model could be relied upon to well predict the behaviors of fluid flow in the proposed cyclone burner, at low to moderate swirl intensities

Solid fuel combustion is always preceded by chemical decomposition. This process is largely determined by the flow structure and affected by the geometry and operating conditions of the combustion chamber. This study aimed to investigate the effect of relative axial inlet diameter (Dai//Dbc) on the flow structure in the proposed cyclone burner. The flow structure was determined with the standard k-Ephsilon turbulent model using the Ansys-Fluent software. From the simulation results it was concluded that with all the axial inlet diameters used an integrated vortex formed in the center of the burner cylinder. The integrated vortex consisted of two vortices, namely a primary vortex and a secondary vortex. The primary vortex penetrated from the furnace box to the burner cylinder, while the secondary vortex was formed in the burner cylinder itself. There were two integration patterns from the primary vortex and the secondary vortex, namely a summation pattern and a multilayer pattern. The presence of a vortex in the center of the burner cylinder is allegedly responsible for an increase in the degree of mixing and pressure drop in that zone. The flow structure induced from the proposed burner had high symmetricity and was largely determined by the burner’s axial inlet diameter.

Silica production from sandstone requires tremendous fossil resources that threaten our environment. Hence, greener resources from biomass should be utilized. One of them is from bamboo leaves which contain rich silica in ash. Even so, acid wash should be applied to achieve higher silica purity. This work aims to investigate the acid wash influences on the physicochemical characteristics of bamboo leaves ash (BLA). The treatment used 1 mol/L HCl under 1-h, 2-h, and no acid wash as a control. The BLA crystallography indicates a fully amorphous phase of silica. Interestingly, 1-h acid wash precisely reduces the silica purity from 95.35% to 94.74%, but it then increases to 96.06% under 2-h acid wash. It is also notified that the longer acid wash duration could alleviate leaves’ mechanical strength. After calcination, consequently, a smaller average particle size of BLA was nominated under 2-h acid wash (6.32 m). It was then followed by 1-h acid wash (21.32 m) and no acid wash (149.44 m). The 2-h acid wash is concluded able to intensify silica purity as well as reduce the particle size of BLA. Finally, acid wash treatment becomes important to facilitate further BLA extraction in order to achieve high purity of silica.

Finding the cheaper alternative fuels and shortening the rendang cooking time are the potential efforts to reduce the production cost of rendang. This study aims to use low-rank cheap coal to cook beef rendang and to develop a more efficient rendang cooking method. First, the raw coals were carbonized, then the charcoals obtained were crushed and mixed with the filler and binder. After that, the charcoal mixture was molded into briquettes. Furthermore, the carbonized coal briquettes resulted were characterized and used as fuel to cook beef rendang in a semi-closed moveable-grate stove. To get a more efficient cooking time, a modified cooking method was developed. From the research has been obtained that there was almost no significant odor and smoke emissions during the cooking process except at the initial ignition period, which takes between 10-15 minutes. The modified cooking method took time 3 hours to get the dry beef rendang, 1 hour shorter than that of the normal cooking ones. Briquettes consumption for 1 kg of beef rendang cooking,using the modified cooking method, was about 0.75 kg, equivalent to USD 0.18 if 1 kg of briquette is priced USD 0.24. Finally, it can be summarized that carbonized coal briquette is a solid smokeless fuel that is safe and cheap to cook beef rendang.

A combination of the experimental and numerical methods was used to investigate the fluid flow behaviors in a proposed cyclone burner. Recirculation flow and pressure drop, two of the important fluid flow behaviors that affect the burner's performance, have been studied here. Experimentally, the recirculation flow phenomenon in the burner was observed through paper slices dynamic in a transparent burner, and pressure drop was measured using a tube manometer. Meanwhile numerically, the fluid flow behaviors were simulated using the standard k-Ephsilon turbulence model, under Ansys-Fluent software. The simulation results showed that, at a certain value of inlet aspect ratio (RIA) and initial tangential intensity (IIT), especially for high IIT, the recirculation flow phenomenon was clearly observed in the center of the burner cylinder which closely resembles a tornado-tail. The indication of existence recirculation flow was also found from the experiment results. The study also exhibited that the results of simulated static pressure drop were closely approaching the experiment results, particularly for IIT values  4.3. The mean deviation of static pressure between the simulation and the experiment results, for a varied range of RIA and IIT, was about 15%. From the results above, it was obvious that fluid flow behaviors (recirculation flow and static pressure) in the proposed cyclone burner are greatly influenced by the RIA and IIT values, where the IIT effect was more significant compared to the RIA. This study also suggests that, the standard k-Ephsilon turbulence model could be relied upon to well predict the behaviors of fluid flow in the proposed cyclone burner, at low to moderate swirl intensities.

Solid fuel combustion is always preceded by chemical decomposition. This process is largely determined by the flow structure and affected by the geometry and operating conditions of the combustion chamber. This study aimed to investigate the effect of relative axial inlet diameter (Dai//Dbc) on the flow structure in the proposed cyclone burner. The flow structure was determined with the standard k-Ephsilon turbulent model using the Ansys-Fluent software. From the simulation results it was concluded that with all the axial inlet diameters used an integrated vortex formed in the center of the burner cylinder. The integrated vortex consisted of two vortices, namely a primary vortex and a secondary vortex. The primary vortex penetrated from the furnace box to the burner cylinder, while the secondary vortex was formed in the burner cylinder itself. There were two integration patterns from the primary vortex and the secondary vortex, namely a summation pattern and a multilayer pattern. The presence of a vortex in the center of the burner cylinder is allegedly responsible for an increase in the degree of mixing and pressure drop in that zone. The flow structure induced from the proposed burner had high symmetricity and was largely determined by the burner’s axial inlet diameter.

The degree of mixing is one of the main indicators of the combustion performance in a combustion chamber. The higher the degree of mixing, the more intensive the contact/reaction between the air and the fuel, so that the combustion performance is getting better. The degree of mixing in a combustion chamber is indicated quantitatively by several variables such as the velocity profiles, the flow structure and the turbulence intensity. The degree of mixing in a combustion chamber is influenced by the factors of geometries and operating conditions. This study is aimed to determine the effect of the inlet aspect ratio (RIA) to the mixing characteristics in a tangential burner. The investigation methodology used in this study is based on the numerical simulation with the Ansys-Fluent simulation code as a Computational Fluid Dynamics (CFD) engine. The fluid flow modelings are performed with the standard k-Ephsilon turbulent model. From the simulations that at mesh interval size smaller than 7 % of the chamber diameter, the standard k-Ephsilon model is able to match satisfactorily the tendency of the experimental velocity profiles available in the literature. The simulation results also show that the inlet aspect ratio has a significant influence to the mixing characteristics in the tangential burner. Within the RIA value that is tested, the best mixing characteristic is found on the burner with the RIA value of 10. The formation of the tornado tail flow structure is determined by the inlet aspect ratio, the total mass flow rate and the swirl number.

Swirl turbulent flow is intensively used by the industrial equipments such as combustion, separation and heat transfer equipments. The fluid dynamic characteristics of this flow are influenced by the chamber’s geometries and the operating conditions. One of the important operating condition variables which greatly affects the fluid dynamic characteristics is initial tangential intensity (ITI) or often known as swirl number. This study is aimed to quantify the effect of the initial tangential intensity on the fluid dynamic characteristics in a tangential burner. The method of the study is based on the computational fluid dynamic simulation under the Ansys Fluent CFD engine. The fluid dynamic characteristics were modeled using the standard k-Ephsilon turbulent model. The simulation results exhibited that the three dimensional flow structure in a tangential burner is dominated by the tangential flow. The fluid dynamic simulations also showed that the effect of the ITI on the mean turbulence intensity and the mean residence time begin to be significant at the ITI values ≥ 1.1 and ≥ 4.5 respectively, while at low ITI values, its effects on both variables are insignificant. The lowest pressure drop obtained in this study was found on the burner with ITI value of 3.2.

The main process of making biobriquettes is carbonization, namely the formation of biomass into charcoal. Carbonization as charcoal producing tool are being developed today. This is conducted to produce maximum and qualified charcoal. In this research, we have made a prototype of multipurpose tool for carbonization. Besides producing charcoal, we can also utilize its smoke as liquid smoke.This tool is called the Pyrolysis Rotary Carbonisator. This carbonization tool is very effective and easy to use in terms of removing charcoal from the carbonization tool. This design can provide optimal results, that give maximum quantity of charcoal and more evenly heat transfer so carbonization process can be perfect and produce high quality of charcoal as material for bio-briquette. Performance evaluations on the tool proof that it has average efficiency of 90%. Another way of evaluating the work is viewed from the temperature of durian shell, palm shell and coconut shell processing with temperature variation of 200, 250, 300 and 400 oC, we also obtained various maximum heat. From this research, maximum calorie of durian shell charcoal at 400 oC is 5628 kcal/kg, while the palm shell at 300 oC is 7578 kcal / kg and the coconut shell at 400 is 7354 kcal / kg

The designed process performances should be fulfilled by the selected proven technology. It has a set of allowable gaps which become the criteria for mechanical and process guarantees. They are quantified by temperature, pressure, yield or conversion, product purity, selectivity, mass flow, and flow behaviors. On the other hand, the designed performances are commonly obtained from long-time experiences in the process of technological development. In addition, gaps between designed and operational unit process performances should meet the acceptability criteria. Geometry is one factor that affects them. Nevertheless, the designed performances may not yet consider the detailed geometries for the operational performances. Another factor is the simplification in the designed stage which does not fit the actual process conditions. Therefore, this study intends to disclose the improvement of unit process performance using the computational fluid dynamics (CFD) method by including detailed geometries and actual conditions. The examined performances of unit processes were focused on three actual industrial cases: furnace, sand settling vessel, and boiler burner. Based on the results, improving the operational unit process performance using the CFD method is more attractive, accurate, and comprehensive.

The behavior of turbulent flow inside cyclones is a complicated matter to study. Fortunately, computational fluid dynamics (CFD) has become a powerful tool for comprehensively digitalizing and visualizing those phenomena. This study, hence, intends to capture and examine the behavior of turbulent flow inside cyclones. They were quantified using the standard k- model. The observed variables comprised static pressure, velocity magnitude, flow pathline, turbulent kinetic energy, and turbulent kinetic dissipation rate. The influence of vortex finder depth and inlet width on flow behavior was also scrutinized. According to the results, the greater turbulence of cyclones was generated at a higher inlet air flow rate and shallower vortex finder depth of below 9 cm or above the inlet air location. Although cyclones with a deeper vortex finder depth of more than 19 cm had a better separation performance, the cyclone manufacturing cost should be considered. Apart from that, the inlet width geometry should not be  15 cm and/or should not be  3 cm because it resulted in poor gas-solid separation performance. Finally, the standard k- model was concluded and proved can reveal the behavior of turbulent flow inside cyclones with logical results and patterns.

The main process of making biobriquettes is carbonization, namely the formation of biomass into charcoal. Carbonization as charcoal producing tool are being developed today. This is conducted to produce maximum and qualified charcoal. In this research, we have made a prototype of multipurpose tool for carbonization. Besides producing charcoal, we can also utilize its smoke as liquid smoke.This tool is called the Pyrolysis Rotary Carbonisator. This carbonization tool is very effective and easy to use in terms of removing charcoal from the carbonization tool. This design can provide optimal results, that give maximum quantity of charcoal and more evenly heat transfer so carbonization process can be perfect and produce high quality of charcoal as material for bio-briquette. Performance evaluations on the tool proof that it has average efficiency of 90%. Another way of evaluating the work is viewed from the temperature of durian shell, palm shell and coconut shell processing with temperature variation of 200, 250, 300 and 400 oC, we also obtained various maximum heat. From this research, maximum calorie of durian shell charcoal at 400 o C is 5628 kcal/kg, while the palm shell at 300 oC is 7578 kcal / kg and the coconut shell at 400 is 7354 kcal / kg

Pra Rancangan Pabrik Metanol dari Gas Alam dengan Kapasitas 460.000 ton/tahun Menggunakan Metode Autothermal Reforming (ATR) direncanakan untuk memenuhi kebutuhan konsumsi metanol dalam dan luar negeri. Dari Analisa teknis dan ekonomi yang dilakukan, maka Pabrik Metanol dari Gas Alam dengan Kapasitas Produksi 460.000 ton/tahun Menggunakan Metode Autothermal Reforming (ATR), layak didirikan pada tahun 2030 di Pandan Jaya, Kecamatan Geragai, Kabupaten Tanjung Jabung Timur, Jambi. Pra Rancangan Pabrik Metanol dari Gas Alam dengan Kapasitas Produksi 460.000 ton/tahun Menggunakan Metode Autothermal Reforming (ATR) merupakan perusahaan berbentuk Perseroan Terbatas (PT) dengan struktur organisasi line and staff dengan jumlah tenaga kerja 135 orang yang terdiri dari 72 karyawan shift dan 63 orang karyawan non shift. Dari perhitungan analisa ekonomi, maka Pabrik Metanol dari Gas Alam dengan Kapasitas Produksi 460.000 ton/tahun Menggunakan Metode Autothermal Reforming (ATR) ini layak didirikan dengan: - Fixced Capital Investment (FCI) = US$ 136.637.087,82 = Rp. 2.082.718.138.581,54 - Working Capital Investment (WCI) = US$ 24.114.427 = Rp. 367.538.495.033 - Total Capital Investment (TCI) = US$ 160.749.515,08 = Rp. 2.450.256.633.551,22 - Total Production Cost (TPC) = US$ 135.626.902,47 = Rp. 2.067.320.186.279,5 - Total Sales (TS) = US$ 152.725.152 = Rp. 2.327.943.674.390 - Internal Rate of Returrn (IRR) = 43% - Pay of Time = 2 Tahun 6 Bulan - Break Event Point (BEP) = 36%

Pabrik Yogurt dari Susu Sapi dengan kapasitas produksi 10.000 Ton/Tahun dengan lokasi pabrik di rencanakan di Kota Padang Panjang, Provinsi Sumatera Barat. Pabrik ini beroperasi selama 300 hari per tahun. Proses produksi yogurt dan Streptococus Thermopilus pada temperatur 43oC. Pabrik ini merupakan perusahaan yang berbentuk perusahaan terbatas (PT) dengan struktur organisasi “line and staff”, dan mampu menyerap tenaga kerja sebanyak 124 orang masa konstruksi pabrik direncanakan selama 2 tahun. Hasil analisa ekonomi pada rancangan pabrik yogurt ini menunjukan bahwwa pabrik ini layak didirikan dengan jumlah total investasi yang dibutuhkan sebesar US$8.195.295,61 atau Rp 124.918.430.069, yang diperolah pinjam bank 50% dan 50% modal sendiri. lalu laju pengembalian modal (IRR) sebesar 32%, waktu pengembalian modal 3 tahun 1 bulan 2 hari dan Break Event Point (BEP) sebesar 31%.

Pabrik Fatty Acid dirancang dengan kapasitas produksi 162.750 ton/tahun dan akan didirikan di Lubuk Gaung, Kota Dumai, Riau-Indonesia. Dasar pemilihan lokasi tersebut adalah dekat dengan penyediaan bahan baku, iklim yang sesuai, dekat dengan jalur transportasi darat dan laut, ketersediaan SDM yang memadai dan utilitas. Pabrik ini beroperasi selama 300 hari per tahun. Fatty Acid yang digunakan sebagai bahan baku diproduksi hingga menjadi beberapa hasil produk lainnya, seperti Caproic Acid, Caprilic Acid, Capric Acid, Lauric Acid, Myristic Acid, Palmitic Acid dan Stearic Acid dan dipasarkan didalam Negeri. Dari hasil perhitungan dan analisis ekonomi pabrik Fatty Acid layak untuk didirikan dengan Total Capital Investment US$ 140.917.354, Laba Bersih US$ 72.561.426, Laju Pengembalian Modal (Rate of Return / ROR) 51,49 %, Waktu Pengembalian Modal (Pay Out Time / POT) 2 Tahun 5 Bulan, Titik Impas (Break Event Point / BEP) 58,64% dan mampu memperkerjakan 100 orang

Pra Rancangan Pabrik Metanol dari Gas Alam dengan Kapasitas 460.000 ton/tahun Menggunakan Metode Autothermal Reforming (ATR) direncanakan untuk memenuhi kebutuhan konsumsi metanol dalam dan luar negeri. Dari Analisa teknis dan ekonomi yang dilakukan, maka Pabrik Metanol dari Gas Alam dengan Kapasitas Produksi 460.000 ton/tahun Menggunakan Metode Autothermal Reforming (ATR), layak didirikan pada tahun 2030 di Pandan Jaya, Kecamatan Geragai, Kabupaten Tanjung Jabung Timur, Jambi. Pra Rancangan Pabrik Metanol dari Gas Alam dengan Kapasitas Produksi 460.000 ton/tahun Menggunakan Metode Autothermal Reforming (ATR) merupakan perusahaan berbentuk Perseroan Terbatas (PT) dengan struktur organisasi line and staff dengan jumlah tenaga kerja 135 orang yang terdiri dari 72 karyawan shift dan 63 orang karyawan non shift. Dari perhitungan analisa ekonomi, maka Pabrik Metanol dari Gas Alam dengan Kapasitas Produksi 460.000 ton/tahun Menggunakan Metode Autothermal Reforming (ATR) ini layak didirikan dengan: - Fixced Capital Investment (FCI) = US$ 136.637.087,82 = Rp. 2.082.718.138.581,54 - Working Capital Investment (WCI) = US$ 24.114.427 = Rp. 367.538.495.033 - Total Capital Investment (TCI) = US$ 160.749.515,08 = Rp. 2.450.256.633.551,22 - Total Production Cost (TPC) = US$ 135.626.902,47 = Rp. 2.067.320.186.279,5 - Total Sales (TS) = US$ 152.725.152 = Rp. 2.327.943.674.390 - Internal Rate of Returrn (IRR) = 43% - Pay of Time = 2 Tahun 6 Bulan - Break Event Point (BEP) = 36%

Pabrik etil asetat dirancang dengan kapasitas 17.000 ton/tahun dan akan didirikan di Kabupaten Mojokerto, Jawa Timur. Dasar pemilihan lokasi tersebut adalah dekat dnegan bajan baku, iklim sesuai, dekat dengan jalur transportasi darat, ketersediaan SDM yang memadai dan utilitas. Pabrik ini beroperasi selama 330 hari per tahun. Etil asetat diproduksi menggunakan bahan baku asam asetat dan etanol. Etil asetat dipasarkan didalam Negeri. Dari hasil perhitungan dan analisa ekonomi pabrik etil asetat layak untuk didirikan untuk didirikan dengan Total Capital Investment US$ 31.663.213,86, Laba bersih US$ 15.032.492, Laju Pengendalian Modal (Internal Rate Of Return / IRR) 47,48%, Waktu pengembalian modal (Pay Out Time / POT) 3 tahun, Titik impas (Break Event Point / BEP ) 47,45% dan mampu memperkerjakan 160 orang.