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Lilik Sutiarso
Departemen Teknik Pertanian dan Biosistem, Fakultas Teknologi Pertanian, Universitas Gadjah Mada, Jl. Flora No. 1, Bulaksumur, Yogyakarta 55281

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Model Matematis Hubungan antara Kadar Air Akhir Bahan dengan Variabel Proses Pengeringan pada Pneumatic Conveying Recirculated Dryer Abadi Jading; Nursigit Bintoro; Lilik Sutiarso; Joko Nugroho Wahyu Karyadi
agriTECH Vol 38, No 2 (2018)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (82.944 KB) | DOI: 10.22146/agritech.15311

Abstract

Flour drying could be conducted by using pneumatic conveying dryer (PCD) or flash dryer, but generally it is required a high vertical pipe. The high of vertical pipe may be replaced with a recirculation process to produce a required final moisture content of the material. This study had designed pneumatic conveying recirculated dryer (PCRD) to dryi of wet sago starch. Later, the design was used to determine a mathematical model of the relationship between the variables of drying process with final moisture content of the material. The purpose of this study was to develop a mathematical model of the relationship between the final moisture content of wet sago starch  with variables drying process and recirculation continuously in the pneumatic conveying recirculated dryer (PCRD) using dimensional analysis. Buckingham Phi Theorem methods of dimensional analysis was used to find the relationship variables that affect the final moisture content of wet sago starch on the PCRD machine. The mathematical model generated in this study is      The coefficient of determination (R2) of the mathematical model was 0.948, or 94.8 %, indicated that the model was valid to predict the final moisture content of wet sago starch in designing PCRD machines. While the sensitivity of the test results showed that the dimensionless product of the most influential are , , and . The model was applicable for drying wet sago starch or other starch material which is similat to the physical properties of wet sago starch. ABSTRAKPengeringan bahan-bahan tepung dapat dilakukan dengan pneumatic conveying dryer (PCD) atau flash dryer, namun umumnya memerlukan pipa vertikal yang cukup tinggi. Pipa vertikal yang tinggi dapat diganti dengan proses resirkulasi untuk menghasilkan kadar air akhir bahan yang disyaratkan. Pada penelitian ini telah dirancang pneumatic conveying recirculated dryer (PCRD) untuk mengeringkan pati sagu basah, serta dicari model hubungan matematis antara variabel-variabel proses pengeringan dengan kadar air akhir. Tujuan penelitian ini adalah mengembangkan model matematis hubungan antara kadar air akhir pati sagu basah dengan variabel-variabel proses pengeringan resirkulasi secara kontinyu pada pneumatic conveying recirculated dryer (PCRD) menggunakan analisis dimensi. Metode Buckingham Phi Theorem dalam analisis dimensi digunakan untuk mencari hubungan variabel-variabel yang berpengaruh terhadap kadar air akhir pati sagu basah pada mesin PCRD. Model matematis yang dihasilkan pada penelitian ini adalah      Nilai koefisien determinasi (R2) dari model matematis tersebut adalah 0,948 atau 94,8 %, menunjukkan bahwa model tersebut valid digunakan untuk memprediksi kadar air akhir pati sagu basah dalam merancang mesin PCRD. Sedangkan hasil uji sensitivitas menunjukkan bahwa dimensionless product yang paling berpengaruh adalah , , dan . Model tersebut berlaku untuk pengeringan pati sagu basah atau bahan-bahan tepung lainnya yang sifat fisiknya identik dengan pati sagu basah.
Optimasi Kualitas Tandan Buah Segar Kelapa Sawit dalam Proses Panen-Angkut Menggunakan Model Dinamis Andreas Wahyu Krisdiarto; Lilik Sutiarso; Kuncoro Harto Widodo
agriTECH Vol 37, No 1 (2017)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (780.788 KB) | DOI: 10.22146/agritech.17015

Abstract

Oil palm fresh fruit bunch (FFB) handling processes, i.e harvesting, loading, and transporting to the Palm Oil Mill are interrelated activities because each of them contributed to the degradation of oil palm fruit quality. This paper presented studied among factors that together in series interfere FFB quality. FFB quality parameter observed was Free Fatty Acid (FFA) content. Experiment was conducted by measuring FFA content of FFB at each step of handling processes, i.e harvesting, transportation in plantation block, loading into truck, and transportation to the palm oil mill. Interrelationship among factors was built using dynamic modelling. Output of dynamic model simulation showed that there was differences of FFA content among different handling conditions. A slight difference on FFA content was observed between harvesting in mineral land and peatland and among different plant heights. Loading into truck was a handling step that had biggest contribution to quality degradation due to FFB bruise. FFBs laid on the base of truck bin suffered more bruise that resulted in higher FFA content. Manual loading of FFB harvested from mineral soil by throwing to the bottom of truck bin resulted in FFA content of bruised fruit by 5.5%, higher compared to those of the top layer which was 4.5%. Model also showed that FFA content increased due to series handling steps, compared with natural degradation. Proportion of good FFB can be used to control the whole FFA content. Without mixing, bruised FFB produced FFA content of 9.95 %, while mixing bruished and good fruit at a ratio 20 % : 80 % resulted in FFA content of 2.82 %. Increasing bruise fruit proportion from 10 % to 20 % resulted in higher FFA content of fruit harvested on mineral land than those harvested on peat land (0.88 % compare to 0.80 %), and resulted in 0.92 % increment for 3rd maturity level fruit harvested compared to 0.72 % for 1st maturity level harvested fruit. Recommendations related to harvesting were: 1) If the road and truck bin was in bad condition, FFB should be harvested at 1st or 2nd level of maturity; 2) The optimum harvesting-transportation condition for FFB quality was at 1st maturity level in peat land and transported by wood bin truck. While recommendations related to transportation were: 1) The manual loading by throwing to truck bin should be avoided; and 2) In order to maintain FFB quality, loading and transportation delay was better than waiting or queing in oil palm mill. ABSTRAKProses penanganan Tandan Buah Segar (TBS) kelapa sawit, yaitu pemanenan, pemuatan, dan pengangkutan ke pabrik minyak kelapa sawit merupakan kegiatan saling terkait, karena masing-masing berkontribusi terhadap penurunan kualitas. Penelitian ini bertujuan mempelajari keterkaitan antar faktor-faktor yang bersama-sama secara berurutan mempengaruhi kualitas TBS. Parameter kualitas TBS yang diamati adalah kadar Asam Lemak Bebas (ALB). Metode yang digunakan adalah mengukur kadar ALB TBS pada setiap tahap proses penanganan bahan, yaitu pemanenan, pengangkutan di dalam blok kebun, pemuatan ke bak truk, dan pengangkutan ke pabrik minyak kelapa sawit. Keterkaitan antar faktor dibangun dengan model dinamis. Keluaran dari simulasi model dinamis menunjukkan bahwa terdapat perbedaan kadar ALB antar kondisi penanganan TBS yang berbeda. Terdapat sedikit perbedaan kadar ALB antara TBS yang dipanen pada lahan mineral dan lahan gambut dan antara ketinggian pohon yang berbeda. Tahap penanganan TBS yang berkontribusi paling besar kepada penurunan kualitas akibat memar adalah pemuatan ke bak truk. TBS yang dimuat di dasar bak truk mengalami memar lebih banyak sehingga kadar ALB-nya lebih tinggi. Kadar ALB TBS yang dipanen di lahan mineral dan dimuat pada dasar bak truk 5,5 %, sedangkan yang di lapisan atas 4,5 %. Model menunjukkan bahwa kadar ALB meningkat pada penanganan bahan berurutan, berbeda dengan penurunan kualitas secara alami. Proporsi buah utuh dapat digunakan untuk mengendalikan kadar ALB secara keseluruhan. Bila seluruh buah memar, kadar ALB dapat mencapai 9,95 %, sedangkan campuran 20 % buah memar dan 80 % buah utuh, kadar ALB-nya 2,82 %. Peningkatan proporsi buah memar dari 10 % menjadi 20 % untuk buah yang dipanen dari lahan mineral menyebabkan penambahan kadar ALB lebih besar daripada buah yang dipanen dari lahan gambut, yaitu 0,88 % dibanding 0,80 %. Hal yang sama menyebabkan perbedaan kadar ALB 0,92 % untuk buah yang dipanen pada fraksi 3 dan 0,72 % untuk buah dipanen pada fraksi 1. Rekomendasi dari hasil penelitian ini adalah: 1) Pemuatan dengan pelemparan TBS secara manual sebaiknya dihindari; 2) Bila kondisi bak truk dan jalan buruk, sebaiknya TBS dipanen pada fraksi 1 atau 2; 3) Titik optimum kualitas TBS saat panen dan angkut adalah pada fraksi 1 di lahan gambut dan diangkut dengan truk bak kayu, dan 4) Dari sisi kualitas TBS, penundaan pengangkutan lebih menguntungkan daripada menunggu proses (mengantri) di pabrik minyak kelapa sawit (PMKS).
Temperature and Air Velocity Simulation on Sago Starch Pneumatic Conveying Recirculated Dryer Using Ansys Fluent Abadi Jading; Nursigit Bintoro; Lilik Sutiarso; Joko Nugroho Wahyu Karyadi
agriTECH Vol 38, No 1 (2018)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (83.968 KB) | DOI: 10.22146/agritech.18251

Abstract

Pneumatic Conveying Recirculated Dryer (PCRD) is one of many driers used for drying wet sago starch. The most important components of this PCRD machine are the vertical pipe and the u-bend. The vertical pipe and the u-bend are the primary drying spaces. They must have a good temperature distribution and air velocity dryer. To observe the process of temperature distribution and the air velocity dryer in the vertical pipe and u-bend, Computational Fluid Dynamics (CFD) analysis is required. The research was aimed to analyze the temperature distribution and the air velocity dryer flow in the recirculated pipe of PCRD machine by using CFD analysis. The analysis was based on the variance of the temperature, the air velocity, and the height of the vertical pipe in PCRD machine. The analysis was conducted using Ansys Workbench Fluid Flow ver. 15. This software was used to simulate the temperature and the air flow velocity in the vertical pipe and the u-bend. However, the flow characteristics and patterns of the wet sago starch were not included in the discussion. The turbulence model used in the simulation was the Reynold Stress Models (RSM). The result of the simulation showed that the temperature along the vertical pipe and the u-bend was distributed evenly. The error value between the result of the simulation and the observation was low (0.10–2.04%). The average test value with paired t-test showed that the simulation and observation result was not significantly different. This results indicated that the simulation fit well with the observation value or the real condition in the PCRD machine. The distribution of the temperature and the air velocity dryer in the vertical pipe and the u-bend were able to reduce the moisture content on sago starch from 31% (wb) to 9% (wb). Therefore, the vertical pipe and the u-bend design was appropriate to use in PCRD machine for drying wet sago starch.
Uji Kinerja dan Implementasi Aplikator Pupuk Cair Berbasis Variable Rate Application untuk Tanaman Kedelai (Glycine max) Miraj Fuadi; Lilik Sutiarso; Radi Radi
agriTECH Vol 41, No 2 (2021)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (582.833 KB) | DOI: 10.22146/agritech.54828

Abstract

Provision of fertilizer is crucial for improving the quality and quantity of the yield. However, using chemical fertilizer continuously with increasing doses can disrupt the balance of land nutrients. Therefore, it is necessary to use a variable-rate liquid fertilizer device to control fertilizer dose required by the plant. The research aimed to evaluate the variable-rate liquid fertilizer performance. The fertilizier applicator characterized by effective field capacity (EFC), theoretically field capacity (TFC) and field efficiency (FE). The materials used were fertilizier (Urea, Sp-36, KCL), Glycine max seeds Grobogan variety. While the equipments were a set of variable-rate liquid fertilizer applicator, scale, rollmeter, analytic balance, multitester, and calipers. To observe the plant responses by fertilizer applicator, a demplot of 36 x 8 m2 was divided in 6 plots of 12 x 4 m2 (A1, A2, ... A6). The evaluation showed respectively the EFC, TFC and FE were 624 m2/h, 864 m2/h and 72.27%. The soybean growth showed that statistically the application of fertilizers using an applicator did not significantly affect plant height parameters but significantly affected the stem diameter, number of leaves and coverage area. Nevertheless, it was still found that soybean crop had different productivity, shown by a significance value of 0.028. Regression analysis with the fertilizer SP-36 (X2) variable on productivity obtained the function Y = -1.405.10-4 + 0.12X2 – 0.001X22 with an R2 of 0.581. Regression analysis with the fertilizer KCl (X3) variable on productivity obtained the function Y = -2.546.10-16 + 0.053X3 – 2.063.10-4 X32 with an R2 value of 0.701.