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Jurnal Rekayasa Proses
Published by Universitas Gadjah Mada
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Search results for , issue "Vol 7, No 1 (2013)" : 5 Documents clear
Coating in Primary Reformer’s Radiant Section Baskara Aji Nugraha
Jurnal Rekayasa Proses Vol 7, No 1 (2013)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (393.581 KB) | DOI: 10.22146/jrekpros.4939

Abstract

Kaltim Parna Industri (KPI) mengalami masalah pada coil heat exchanger pada bagian konveksi primary reformer yang memanfaatkan panas flue gas yaitu berupa fouling pada bagian luar tube coil exchanger (finned tube). Pada awalnya belum diketahui sumber penyebab fouling, namun dari hasil analisis laboratorium diketahui bahwa komponen penyusun fouling sama dengan komponen firebrick (batu tahan api). Oleh karena itu diambil kesimpulan bahwa penyebab fouling adalah firebrick yang tererosi lalu terbawa aliran flue gas. Salah satu cara untuk menghilangkan sumber fouling adalah dengan melakukan coating pada ruang bakar yang terdapat firebrick di dalamnya. Coating dilakukan dengan menggunakan cat khusus yang tahan suhu tinggi yang mampu menahan permukaan fire brick dari erosi. Kata kunci: seksi konveksi, fouling, pelapisan, firebrick, reformer Kaltim Parna Industri, (KPI), experienced severe fouling on the flue gas side of the coil heat exchangers. This happened on the outer tube side, which some were finned tubes. Although the cause had not clearly been identified, laboratory analysis indicated that the fouling had similar composition with the firebrick. Therefore, preliminary assumption of what causes the problem was firebrick erosion that was carried away by flue gas flow. In order to completely eliminate fouling source and hopefully to reduce cleaning frequency, we planned to coat combustion chamber with special high temperature resistance coating.The result was promising that the material was stable against high temperature and even further helped the operation. Keywords: convection section, fouling, coating, firebrick, reformer
Aplikasi Analisis Pinch untuk Menurunkan Konsumsi Steam di Bagian Process House Pabrik Gula Daniyanto
Jurnal Rekayasa Proses Vol 7, No 1 (2013)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (576.175 KB) | DOI: 10.22146/jrekpros.4940

Abstract

Salah satu indikator efisiensi energi pabrik gula adalah Steam on Cane (SOC). SOC menunjukkan pemakaian steam tiap berat tebu. Semakin kecil SOC, efisiensi energi pabrik gula semakin baik. Sumber bahan bakar utama pabrik gula adalah bagasse. Bagasse merupakan ampas hasil ekstraksi tebu. Pabrik gula yang efisien akan memiliki SOC kurang dari 50%. Nilai SOC lebih dari 50% menyebabkan pabrik gula harus menggunakan tambahan bahan bakar selain bagasse. Jika SOC kurang dari 40 % berat tebu maka pabrik gula bisa melakukan kogenerasi dan menghasilkan listrik untuk dijual. Penelitian ini bertujuan untuk menurunkan SOC dengan cara menurunkan konsumsi steam di process house melalui inovasi konfigurasi proses dengan analisis pinch. Hasil penelitian menunjukkan bahwa analisis pinch bisa digunakan untuk menurunkan konsumsi uap di pabrik gula. Penggunaan uap evaporator dari unit multiple effect evaporator akan mampu menurunkan konsumsi uap bagian process house. Perubahan konfigurasi proses memberikan penurunan SOC sebesar 8,8% dari kondisi semula. Uap evaporator 2 bisa digunakan untuk sumber panas pemanas 1 dan pemanas 2, uap evaporator 1 untuk sumber pemanas vacuum pan dan exhaust steam hanya digunakan untuk pemanas 1 dan vacuum pan. Kata kunci: efisiensi energi, steam on cane, kogenerasi, konfigurasi proses, analisis pinch. The energy efficiency of sugar factory can be indicated by variable steam on cane (SOC). SOC is defined as weight of steam consumption per weight of crushed cane. The smaller the SOC, the energy efficiency of sugar mills is better. The main source of fuel in sugar mill is bagasse. The sugar factory will be efficient if SOC is less than 50%. If SOC value is more than 50%, it will cause additional fuel other than bagasse. If SOC is less than 40%, the cane sugar mill can do cogeneration and produce electricity for sale. This study aims to reduce SOC by reducing steam consumption in the process house through configuration process innovation with pinch analysis. The results showed that pinch analysis could be used to reduce steam consumption in sugar mill. Utilization of steam from evaporator could reduce steam consumption in the process house. The change in process configuration could provide SOC decrease by 8.8% from its former state. Steam produced by evaporator 2 could be used as heat source for heater 1 and heater 2, meanwhile steam produced by evaporator 1 as a heat source for vacuum pan. Exhaust steam could be used only for heater 3 and vacuum pan. Keywords: energy efficiency, steam on cane, cogeneration, process configuration, pinch analysis.
Modifikasi Mekanisme Koufopanos pada Kinetika Reaksi Pirolisis Ampas Tebu (Bagasse) Emi Erawati; Wahyudi Budi Sediawan; Panut Mulyono
Jurnal Rekayasa Proses Vol 7, No 1 (2013)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (454.757 KB) | DOI: 10.22146/jrekpros.4941

Abstract

Ampas tebu merupakan produk samping dari ekstraksi gula. Ampas tebu yang dihasilkan di pabrik gula sekitar 13% dari tebu yang digiling. Tujuan penelitian ini adalah menentukan energi aktivasi dan pre-exponential factor pada persamaan kinetika reaksi pirolisis ampas tebu. Pirolisis dilakukan dalam reaktor yang terbuat dari pipa besi jenis 5737 dengan diameter 7,62 cm dan panjang 37 cm. Reaktor ini dimasukkan ke dalam furnace yang berdiameter 15,24 cm dan panjang 40 cm. Seratus lima puluh gram ampas tebu dimasukkan ke dalam reaktor tanpa kehadiran oksigen pada tekanan atmosferis. Pirolisis dilakukan pada berbagai ukuran bahan, yakni: (-20+25), (-25+30), (-30+35), (-35+40), -40 mesh dengan kecepatan pemanasan bervariasi 100, 105, 115, dan 120 volt. Modifikasi mekanisme Koufopanos terdiri dari 4 tahap reaksi, yaitu: bahan baku bereaksi menjadi intermediate dan intermediate bereaksi menjadi gas, cair, dan padatan. Berdasarkan data eksperimen, diperoleh data parameter kinetika reaksi overall rata-rata E1, E2, E3, dan E4 masing-masing sebesar 8.750,48; 2.350,7;11.080,97; dan 6.625,49 J/mol, dengan pre-exponential factor yang bersesuaian A1, A2, A3, dan A4 sebesar 9,20x10-3; 2,13x10-2; 1,67; dan 2,31 detik pada variasi diameter partikel dan kecepatan pemanasan. Kata kunci: energi aktivasi, ampas tebu, mekanisme Koufopanos, pirolisis, kinetik. Bagasse is a side product of sugar cane extraction. A sugar factory produces bagasse of about 13% from the total cane milled. According to the data from BPPS (1999-2007) the total bagasse produced is about two million tons. The aim of this study is to determine the value of activation energy and pre-exponential factor of pyrolysis kinetics of sugar cane bagasse. Pyrolysis had been carried out in a reactor made of steel pipe type 5737 with a dimension of 7.62 cm dia and of 37 cm long.The reactor was inserted into a furnace with a diameter of 15.24 cm and a length of 40 cm. One hundred and fifty grams of bagasse had been added into the reactor without the presence of oxygen at atmospheric pressure. Pyrolysis had been carried out at the particle size of (-20+25) mesh, (-25+30) mesh, (-30+35) mesh, (-35+40) mesh, and -40 mesh and heating rate of 100, 105, 115, and 120 volt. Modification of Koufopanos mechanism described four reaction steps, namely the reaction to produce intermediate product and further reaction in which intermediate product converted into gas, bio-oil, and char product was the most appropriate reaction model. From the modified model the activation energy E1, E2, E3, and E4 was 8,750.48; 2,350.7 ; 11,080.97 ; and 6,625.49 J/mol, respectively, while the pre-exponential factor A1, A2, A3, and A4 was 9.20x10-3 ; 2.13x10-2 ; 1.67 ; and 2.31 second, respectively for various size particles and heating rates. Keywords: activation energy, bagasse, Koufopanos mechanism, pyrolysis, kinetic.
Studi Pemanfaatan Condensate Outlet Steam Trap Sebagai Air Umpan Boiler di Pabrik Amoniak Pusri-IB Alfa Widyawan; Ferlyn Fachlevie
Jurnal Rekayasa Proses Vol 7, No 1 (2013)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (629.498 KB) | DOI: 10.22146/jrekpros.4942

Abstract

Sebagai produsen amoniak dan urea, PT. Pusri memerlukan steam dalam jumlah yang relatif besar. Steam di pabrik amoniak digunakan sebagai bahan baku pabrik amoniak, sebagai pemanas dan penggerak turbin. Tekanan steam yang digunakan di pabrik Amoniak P-IB bervariasi, dari 3,5 kg/cm2gauge sampai 123 kg/cm2gauge. Distribusi steam yang dialirkan melalui pipa menuju peralatan mengakibatkan kehilangan panas ke lingkungan. Hal ini menyebabkan terbentuknya steam condensate di sepanjang aliran pipa. Selama ini steam condensate yang keluar dari pipa melalui steam trap langsung dibuang ke sewer. Studi ini dimaksudkan untuk menghitung laju kondensasi steam dan kelayakan ekonomi untuk memanfaatkan steam condensate tersebut sebagai air umpan boiler di pabrik Amoniak P-IB. Perpindahan panas di pipa dihitung menggunakan prinsip perpindahan panas konduksi, konveksi dan radiasi. Perhitungan laju kondensasi steam dilakukan dengan variasi tekanan steam 123, 42 dan 3,5 kg/cm2gauge, variasi tebal pipa 4 hingga 20 inchi serta variasi tebal isolasi 1 sampai 4 inch. Laju kondensasi steam dinyatakan dalam suatu persamaan matematis yang merupakan fungsi dari tebal isolasi dan diameter pipa. Hasil perhitungan menunjukkan bahwa laju kondensasi steam membesar bila tekanan steam naik, tebal isolasi turun, dan diameter pipa membesar. Penghematan yang didapat apabila steam condensate dimanfaatkan sebagai air umpan boiler berasal dari penghematan produksi air demin dan penghematan bahan bakar akibat perbedaan suhu antara steam condensate dan air demin dengan simple payback period selama 0,9 tahun. Kata kunci: steam condensate, kehilangan panas, laju kondensasi steam, penghematan As ammonia and urea producer, PT. Pusri consumes a lot of steam, which is used as raw material in ammonia plant, as well as heating medium and turbine driving agent. Steam pressure used in the P-IB Ammonia plant varies from 3.5 to 123 kg/cm2gauge. Distribution system of steam piping to the equipments causes heat loss to the environment. This leads to the production of steam condensate flowing along the pipe. The steam condensate from the pipe (through the steam trap) is directly discharged into the sewer. The present study aimed to determine the rate of steam condensation and to elaborate an economic feasibility to utilize the condensate as boiler feed water in the Ammonia plant P-IB. Calculation of heat transfer in the pipes was based on the principles of conduction, convection and radiation. The rate of steam condensation was calculated with steam pressure variation from 3.5 to 123 kg/cm2gauge, pipe diameter from 4 to 20-inch and insulation thickness of 1 to 4 inches. The rate of condensation was expressed in a mathematical equation and was a function of insulation thickness and diameter of pipe. The results showed that the rate of steam condensation rised as steam pressure and pipe diameter increased and insulation thickness decreased. Operating cost reduced if the steam condensate was used as boiler feed water replacing demineralized water. This also caused reduction of fuel consumption and therefore resulted in simple payback period of 0.9 years. Keywords: steam condensate, heat loss, steam condensation rate,cost reduction
Pengolahan Gas CO2 Hasil Samping Industri Amoniak Melalui Gasifikasi Batubara yang Telah dipirolisis dengan Menambahkan Ca(OH)2 Saripah Sobah; Hary Sulistyo; Siti Syamsiah
Jurnal Rekayasa Proses Vol 7, No 1 (2013)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (232.76 KB) | DOI: 10.22146/jrekpros.4943

Abstract

Gas CO2 merupakan salah satu gas rumah kaca yang dianggap memiliki kontribusi terhadap pemanasan global. Industri amoniak menghasilkan emisi CO2 cukup besar dengan faktor emisi 3,273 ton CO2/ton amoniak. Salah satu upaya untuk mengurangi emisi gas CO2 yang dapat dilakukan adalah mengkonversi gas CO2 menjadi gas sintesis (CO) melalui proses gasifikasi batubara. Gas CO merupakan salah satu bahan baku pembuatan metanol. Penelitian ini bertujuan untuk mengetahui seberapa besar gas CO2 dapat dikurangi kadarnya melalui proses gasifikasi arang batubara. Reaksi karbon dari arang batubara dengan gas CO2 pada proses gasifikasi merupakan reaksi endotermis dan berlangsung sangat lambat pada suhu di bawah 1000oC sehingga digunakan Ca(OH)2 sebagai katalisator. Proses gasifikasi batubara dijalankan dalam reaktor fixed bed. Hasil penelitian menunjukkan bahwa gasifikasi arang batubara dengan penambahan Ca(OH)2 pada proses pirolisis dapat mengurangi gas CO2 sampai sebesar 63,17%, sementara untuk gasifikasi tanpa Ca(OH)2 , gas CO2 hanya berkurang sampai 35,2%. Kata kunci: karbondioksida, pemanasan global, gasifikasi, arang batubara, kalsium hidroksida CO2 is one of the greenhouse gases that is considered to cause global warming. Ammonia industry produces emission gas of CO2 in relatively great amount with an emission factor of 3.273 ton CO2/ton ammonia. One of the attempts to reduce CO2 gas emissions is by converting CO2 into syngas (CO) through gasification process. CO is one of the methanol feedstock. This research aimed to find out the amount of CO2 that can be reduced through charcoal gasification process. The reaction of carbon from coal can be reduced through the gasification process. Since the carbon reaction from coal with CO2 gas in the gasification process was an endothermic and occured very slowly at temperatures below 1000°C, Ca(OH)2 was used as a catalyst. The coal gasification process was conducted in a fixed bed reactor. The experimental results showed that coal gasification with the use of Ca(OH)2 in the pyrolysis process could reduce CO2 levels by 63.17%, meanwhile without Ca(OH)2, the CO2 could be reduced only up to 35.2%. Keywords: carbon dioxide, global warming, gasification, charcoal, calcium hydroxide.

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