46 research outputs found
Carbon Capture and Storage System Using Pinch Design Method
No full textCarbon capture and storage (CCS) have been investigated for a long time. It was intended to reduce carbon dioxide (CO2) in the atmosphere due to fossil fuel combustion in power generation and industrial processes. CO2 is captured and stored in various geological formations. The problem here is to match between source and sink such that alternative storage and unutilized storage capacities are minimum. Pinch Design Method as has been proposed by was used in this work. The concept is overwhelming that it can be used other than in the heat exchanger networks, such as in the water system design, mass exchanger networks and many other processes. Initially this concept was applied to carbon capture and storage but with no exact pairing between sources and sinks as proposed in this work using grid diagram as commonly shown in other processes. This work can point out the exact pairing between sources and sinks, and within the given time frame. A four different cases are investigated where the time difference between the starting time of CO2 generated in the source and the beginning of sink availability. A value of 0, 5, 10 and 15 years are chosen to evaluate the amount of CO2 that has to be stored and the amount of unutilized storage capacity. The case study has been prepared with 5 sources and 3 sinks. The result shows that the larger time difference the larger alternative storage and unutilized storage capacities. Therefore, having a shorter time difference will be more acceptable in the design CCS system
Technical and economical evaluation of carbon dioxide capture and conversion to methanol process
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Analysis of several control structures on autorefrigerated reactor.
Full text linkAutorefrigerated reactor is a chemical reactor that uses latent heat to remove accumulation of heat formed from exothermal chemical reaction. It has been previously investigated that using temperature controller, the response of temperature towards disturbance of feed flow rate was found to be good and the process was controllable.
Several control structures in this paper were applied to this reactor and explored their behaviors towards disturbance from feed flow rate. These include product composition control, reaction rate control, and cascade control which are believed to give a better result than the conventional control structure. A change of 10 % of feed flow rate was assumed. A comparison on the settling time, overshoot and deviation magnitude of the desired output was studied. Controller parameter were tuned according to Relay Feedback Test â Auto Tuning Variation. The results show that temperature control yield better performance in terms of less overshoot and settling time, while product composition surprisingly gives inferior performance compared to the other one. The settling time for product composition control is 90.77 hour compared to 0.52 hour for temperature control. Minimum IAE for temperature control support the advantage of using this control structure. Deviation magnitude of the desired output appeared to be insignificant for all controller structures
A Modified Shrinking Core Model for Leaching of Aluminum from Sludge Solid Waste of Drinking Water Treatment
Full text linkThe kinetics of aluminum leaching from sludge solid waste (SSW) using hydrochloric acid at different leaching temperatures (30-90°C) was studied. A mathematical model was developed based on a shrinking core model by assuming first-order kinetics mechanisms for leaching and an equilibrium linear at the solid-liquid interface. The proposed model is suited to fit experimental data with three fitting parameters and to simulate the leaching of aluminum from SSW, which was validated with the mass transfer coefficient (kc , cm/s), diffusion coefficient (De, cm2/s), and reaction rate constants (k, cm/s). The evaluated kc , De , and k are expected to follow an increasing trend with increasing temperature. The correlation coefficient ? 0.9795, the root mean square error ? 0.399, the mean relative deviation modulus ? 6.415%, and the value of activation energy is 13.27 kJmol-1. The proposed model could describe the kinetics of aluminum leaching from the SSW DWT in accordance with test parameters and relevant statistical criteria. Valuable information on the results of this work can be given for the purposes of the simulation, optimization, scaling-up, and design of the leaching process
PEMILIHAN TEKNOLOGI PROSES GEOTHERMAL SECARA TEKNIS PADA PEMBANGKIT LISTRIK TENAGA PANAS BUMI DI INDONESIA
Full text linkSaat ini, geothermal power plant memproduksi beban dasar listrik yang lebih murah, handal dan ramah lingkungan. Namun efisiensi konversi yang terdapat pada pembangkit listrik tenaga panas bumi sangatlah kecil daripada pembangkit listrik tenaga fosil lainnya. PT. Geo Dipa Energi unit Dieng, Jawa Tengah merupakan salah satu perusahan pembangkit listrik di Indonesia yang memanfaatkan energi panas bumi berupa steam sebagai penggerak utama dengan teknologi flash steam. Pemilihan teknologi proses flash steam telah dikembangkan dengan model pendekatan matematis berdasarkan hukum termodinamika menggunakan software Engineering Equation Solver (EES). Pada penelitian ini dapat disimpulkan bahwa kualitas fisik steam yang dihasilkan dari sumur produksi dalam suhu 306 â°C dan mempunyai nilai entalpi sebesar 1379,7 kJ/kg, Kondisi operasi separator yang digunakan perangkat lunak EES berada di suhu 179,9 â°C dan tekanan 1000 kPa dengan menghasilkan daya listrik sebesar 13.929,63 kWe dengan besarnya efisiensi 23,41 %. Telah dikembangkan simulasi pemodelan dengan kombinasi antara single flash steam dengan binary cycle. Kombinasi teknologi single flash steam dan binary cycle ini menghasilkan daya sebesar 18.456,24 kW dengan efisiensi overall plant sebesar 31,02 %. Hal tersebut memiliki efisiensi terbesar sehingga dirujuk sebagai pilihan teknologi proses geothermal yang tepat untuk PLTP PT. Geo Dipa Energi unit Dieng, Jawa Tengah. Sedangkan teknologi kombinasi single flash dengan dual binary cycle ini menghasilkan daya sebesar 18.329,768 kW dengan efisiensi overall plant sebesar 30,81 %
Cleaning Schedule Operations in Heat Exchanger Networks
No full textHeat exchanger networks have been known to be the essential parts in the chemical industries. Unfortunately, since the performance of heat exchanger can be decreasing in transferring the heat from hot stream into cold stream due to fouling, then cleaning the heat exchanger is needed to restore its initial performance periodically. A process of heating crude oil in a refinery plant was used as a case study. As many as eleven heat exchangers were used to heat crude oil before it was heated by a furnace to the temperature required to the crude unit distillation column. The purpose of this study is to determine the cleaning schedule of heat exchanger on the heat exchanger networks due to the decrease of the overall heat transfer coefficient by various percentage of the design value. A close study on the process of heat exchanger cleaning schedule in heat exchanger networks using the method of decreasing overall heat transfer coefficient as target. The result showed that the higher the fouling value the more often the heat exchanger is cleaned because the overall heat transfer coefficient decreases quickly
KINETIC MODEL FOR IDENTIFYING THE RATE CONTROLLING STEP OF THE ALUMINUM LEACHING FROM PEAT CLAY
No full textThe aluminum (Al) leaching kinetics from peat clay was investigated using various acid concentrations 1 M to 6 M, particle sizes +70-120 mesh to +200-325 mesh and temperatures 30 °C to 90 °C. They all have significant effects on aluminum leaching process. The Al leaching recovery was best found to be 91.3 % at 4 M hydrochloric acid (HCl), using a particle size of +200-325 mesh with solid/liquid of 0.02 g·ml-1. Leaching kinetic study was applied to the two rate equations proposed that is acid diffusion via product layer and surface chemical reaction using the shrinking core (SC) model to analyze the leaching data. The product layer diffusion is controlling Al leaching process for one-stage model, while for two-stage model, it was controlled by surface chemical reaction. The activation energy in the two rate controlling step was 82.79 kJ mol-1 and 27.08 kJ mol-1, respectively. </jats:p
