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"ABSTRAKAdanya ketidaklinearan pada reaktor alir tangki berpengaduk mampu menyebabkan gangguan ketika proses sedang berjalan. Gangguan tersebut menyebabkan turunnya kualitas produk, sehingga diperlukan penanganan terhadap gangguan. Skripsi ini membahas penggunaan Representative Model Predictive Control (RMPC) dalam memilih beberapa model predictive control (MPC) lokal yang kemudian dikombinasikan untuk membuat Multi Model Predictive Control (MMPC), dan digunakan untuk menangani gangguan pada proses. Penelitian ini menggunakan model reaktor Bequette dan disimulasikan menggunakan perangkat lunak MATLAB. Variabel bebasnya adalah konsentrasi feed sedangkan variabel kontrolnya adalah konsentrasi produk dan suhu reaktor. Hasil dari penelitian menunjukkan IAE MMPC lebih kecil dari IAE PI.

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ABSTRACTExisting nonlinearity in continuous stirred tank reactor can cause disturbances when the process is running. Those disturbances cause a decline in product quality, so that disturbances rejection control is needed. The use of Representative Model Predictive Control (RMPC) in selecting some of the local Model Predictive Control (MPC) and then combined to make Multi Model Predictive Control (MMPC) are discussed and explained. MMPC, a Bequette reactor model, and MATLAB software were used and applied to handle disturbances and simulate. Manipulated variable is feed concentration while the controlled variables are product concentration and reactor temperature. The results of this study show that IAE value of MMPC is smaller than IAE value of PI."

"Air limbah sebelum dibuang ke lingkungan harus memenuhi baku mutu lingkungan, di antaranya memenuhi pH netral. Karena itu, pengendalian pH sangat penting dilakukan. Unit mini plant WA921 bekerja untuk mengolah air buangan asam atau basa seperti yang digunakan di industri. Semula setelan parameter pengendali PID dan PID Non-linear didasarkan pada kondisi air di tempat peralatan itu dibuat sehingga perlu diuji kinerjanya dengan menggunakan kondisi air lokal. Penelitian sebelumnya sudah mendapatkan setelan parameter pengendali PID yang optimum, sedangkan setelan parameter pengendali PID Non-linear yang optimum belum dievaluasi. Pengujian kinerja dilakukan pada kondisi air lokal dengan pH larutan asam dan basa 0,1 N, dan perubahan pH dari 3,8 ke 7,0 dalam rangka mendapatkan kondisi non-linear. Hasilnya, untuk skema proses Short didapat setelan terbaik parameter pengendali PID non-linear adalah PB 10, Ti 120, Td 10, Gw 10, dan Gg 0.3 dengan IAE (integral of absolute error) sebesar 154, lebih kecil dibanding dengan IAE pengendali PID linear sebesar 223. Sedangkan untuk skema Long, setelan terbaiknya pada PB 5, Ti 425, Td 40, Gw 30, dan Gg 0.25 dengan IAE sebesar 656 lebih kecil dibanding dengan IAE PID linear sebesar 888.

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Waste water before discharge into the environment must meet environmental quality standards, of which meets a neutral pH. Therefore, pH control is very important. WA921 unit mini plant work for processing waste water of acid or base as used in the industry. Original PID controller parameter settings and Non-linear PID based on water conditions at the place it was made, so that the equipment needs to be tested its performance by using local water conditions. Previous research had a PID controller parameter setting reach the optimum, while the non-linear PID controller parameter setting the optimum has not been evaluated. Performance testing conducted on local water conditions with a pH of 0.1 N acid and base, and changes in pH from 3.8 to 7.0 in order to obtain non-linear conditions. The result, for the scheme Short the best suits obtained for non-linear PID control parameters are PB 10, 120 Ti, Td 10, Gw 10, and 0.3 Gg by IAE (integral of absolute error) of 154, is smaller than the IAE for PID linear controller 223. As for the scheme Long, his best suit on the PB 5, 425 Ti, Td 40, Gw 30, and 0:25 with IAE Gg of 656 smaller than the IAE for PID linear 888."

"The mathematical model was selected and the empirical equations were formulated from laboratory measurement by disturbed soil that was applied in undisturbed soil or field so required a correction factor. The correction factor could be expressed as a value of channeling fraction. The channeling process will affect to the average velocity of soil solution flow in soil. The average velocity of soil solution flows in soil controlled the fate of pesticide in undisturbed soil. The soil solution flows at undisturbed soil were expressed as two difference velocity values. The first part has equal velocity as its superficial velocity. The second part, because of chanelling, it was arbitrarily determined to be 10 times of the superficial velocity, and therefore, the superficial velocity of soil solution in the undisturbed soil must be corrected by the channeling fraction. The objective of the verification experiment was to identify a correction factor that could be expressed as channeling fraction in the equation as follows:V undisturbed soil = (1-channeling fraction) V Superficial + chanelling fraction (10 x v superficial)The verification was carried out at undisturbed soil obtained from three locations. The undisturbed soil in PVC pipe was saturated with water. After a saturated condition is reached, the flow direction of water was turned from top to bottom. The water continuously flows. After the steady state condition, water flow were substituted with the flow of fenitrothion solution, at the time was regarded as an initial condition (t=0). At the certain time the soil solutions at the outlet were taken to be determined the concentration of fenitrothion by HPLC. Based on the selected mathematical model and theempiricial equitations, the concentration of pesticide in soil solution as a position and time function can be calculated. The correction factor or the channeling fraction could be evaluated by comparing the fenitrothion concentration as a time function, from laboratory experiment data and from mathematical simulation result. The obtained channeling fraction values are 0.03, 0.05, and 0.1 for the clay loam-clay, the sandy loam-sand, and the loam-sandy loam textures, respectively."

"Konsumsi energi proses produksi klor alkali yang tinggi mendorong perlu dilakukannya peningkatan efisiensi proses. Elektrolisis plasma merupakan modifikasi proses elektrolisis yang dapat meningkatkan nilai produksi dan efisiensi energi hingga berkali-kali lipat. Penelitian ini menggunakan larutan kalium klorida sebagai bahan baku elektrolisis untuk memproduksi gas klor sebagai produk utama. Pada penelitian ini, berbagai fenomena terkait pembentukan plasma dijelaskan, seperti intensitas warna, penurunan nilai arus, dan pengaruh ketinggian elektroda. Hasil penelitian menunjukkan efisiensi tertinggi didapat pada konsentrasi tertinggi dan tegangan 400 V dengan peningkatan efisiensi terhadap proses elektrolisis mencapai 13 kali lebih besar.

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High energy consumption of chlor-alkali process encourage the importance of the efficiency improvement. Plasma electrolysis is a modification of electrolysis method that can increase productiviy and efficiency level up to several times. This study uses a solution of potassium chloride as a raw material to produce chlorine gas as the main product.

In this study, various phenomena related to plasma formation are described, such as color intensity, decreasing of the current value, and the influence of the electrode height. The results showed the highest efficiency obtained at the highest concentration and 400 volt with an increase in the efficiency of the electrolysis process at 13 times greater."

"Reaktor plasma dengan konfigurasi umpan 3-lewatan untuk konversi gas CO2 dan CH4 perlu dimodelkan agar dapat merepresentasikan fenomena fisika dan kimia yang terjadi dalam reaktor. Pemodelan ini juga bertujuan mendapatkan kinerja reaktor yang diinginkan agar bisa digunakan sebagai dasar scale-up. Model reaktor disimulasikan dalam tiga dimensi menggunakan COMSOL Multiphysics dengan melihat pengaruh variasi laju alir umpan, temperatur di dalam reaktor, serta rasio mol umpan terhadap konversi dan produk syngas yang dihasilkan. Konversi tertinggi dicapai pada laju alir 4,6 mL/ menit dengan konversi CO2 sebesar 22% dan konversi CH4 sebesar 88,4% dengan rasio syngas yang dihasilkan CO2: CH4 = 1:1,14. Konversi yang dihasilkan tidak mengalami perubahan yang signifikan dengan naik atau turunnya temperatur di dalam reaktor. Dari variasi rasio mol umpan, konsentrasi CO yang dihasilkan meningkat sebanding dengan naiknya konsentrasi umpan CO2. Konsentrasi H2 yang dihasilkan meningkat sebanding dengan naiknya konsentrasi umpan CH4.

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Plasma reactor with 3-pass flow configuration for conversion CO2 and CH4 gas needs to be modeled in order to represent the physical and chemical phenomena that occur in the reactor. This modeling also aims to obtain the desired performance of the reactor to be used as the basis for scale-up. Reactor modeled in three dimensions using COMSOL Multiphysics to see the effect of the feed flow rate variations, the temperature inside the reactor, as well as the mole ratio of the feed to the conversion and syngas produced. The highest conversion achieved at a flow rate 4.6 mL/min, respectively the conversion of CO2 and CH4 is 22% and 88.4% with a ratio syngas produced CO2: CH4 = 1: 1.14. The conversion in the reactor did not change significantly with the increase or decrease the temperature in the reactor. The concentration of CO produced increase with increasing inflow concentration of CO2. The concentration of H2 produced increase with increasing inflow concentration of CH4."

"Penelitian ini membandingkan karakteristik pengabutan dan pembakaran dari campuran minyak nabati dan bahan bakar minyak pada setiap rasio pencampuran nya. Semburan nyala api pada pembakaran yang beroperasi pada tekanan 0,2 hingga 1,2 bar diamati secara optis. Bahan bakar nabati (BBN) memiliki kekentalan (viskositas) yang besar sehingga menjadi kendala dalam proses pembakaran. Karena itu untuk menurunkan viskositas nya perlu dicampur dengan bahan bakar minyak (BBM). Pembakaran yang baik memerlukan proses pengabutan yang baik. Pada penelitian ini proses pengabutan nya menggunakan nosel jet. Pengukuran kualitas pengabutan dan pembakaran dilakukan dengan metode fotografi dan perangkat lunak pemrosesan citra. Hasilnya menunjukkan bahwa rasio campuran BBN dan BBM yang terbaik adalah 40% : 60% untuk semua jenis campuran (minyak jelantah dan solar, minyak curah dan solar, minyak nyamplung dan solar serta minyak curah dan minyak tanah) dan tekanan operasi terbaik adalah 1,2 bar. Pada kondisi tersebut, campuran minyak curah dan minyak solar memiliki rerata suhu nyala yang paling tinggi (391,6oF) dan distribusi partikel aerosol terkecil yang paling tinggi (73%) meskipun masih di bawah BBM murni (100%).

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The spray atomization and combustion characteristic of vegetable oil and fosil fuel are compared to those ratio of mixtures on this paper. The spray flame was contained in an optically accessible combustor which operated at 0,2 - 1,2 bar of air pressure. Vegetable Fuel (VF) contains high viscosity that has been a, constraint in the combustion process; it needs to be mixed with Fosil Fuel (FF) in order to decrease the VF viscosity. A fine atomization process is necessary to fix the combustion. Research of atomization process was tested by using nozzle jet. The atomization and combustion quality were investigate by photographic method and image processing software was used to measure the spray droplet size. As a testing result, ratio mixture of 40% : 60% of VF and FF was good ratio mixtures ( used cooking oil diesel oil, cooking oil and diesel oil, nyamplung oil and diesel fuel, cooking oil and kerosene) compared to others ratio which operated at 1,2 bar of air pressure implying flame temperature. The flame temperatur of cooking oil and diesel oil mixture reached (391,6oF) as the highest mean temperature and distribution of aerosol particle reached (73%) although produced lower than fosil fuel (100%)."