scholarly journals Dynamic Study of Feed-Effluent Heat Exchanger Addition on Double Bed Configuration Ammonia Reactor System within Varied Quenching Ratio

2018 ◽  
Vol 156 ◽  
pp. 03047 ◽  
Author(s):  
Tri Partono Adhi ◽  
Ferdyan Ihza Akbar
Keyword(s):  
Heat Exchanger ◽  
Ammonia Synthesis ◽  
Volume Ratio ◽  
Operating Parameters ◽  
Hysteresis Phenomenon ◽  
Simulation Tool ◽  
Synthesis Reaction ◽  
Aspen Hysys ◽  
Feed Temperature ◽  
Varied Parameter

Ammonia is one of the most important industrial commodity due to its wide function. Ammonia synthesis reaction is an exotermic reaction. Therefore, Feed-Effluent Heat Exchanger (FEHE) is added to increase thermal efficiency. However, FEHE could lead the process to experience hysteresis phenomenon due to interaction between equipments as one steady state T feed could result several T outlet. Hysteresis phenomenon may result asset losses like explosion, leakage, and loosing material integrity. Double bed reactor configuration allows us to use several operating parameters as variation to overcome hysteresis. In this review, quenching ratio was chosen to be that varied parameter. This study aims to determine how quenching ratio affects hysteresis zone by utilizing Aspen Hysys® V8.8 as simulation tool. Simulation showed that quenching ratio would narrow hysteresis zone yet increased extinction temperature that lower the conversion. Conversion profile showed that 0.2 quenching ratio got the highest conversion for system with bed volume ratio 2:1 while total volume was 30 m3. However, the feed temperature was fallen at hysteresis zone. Dynamic simulation showed that highest conversion feed temperature (10%ΔTf above extinct temperature) was still able to preserve stability with descending temperature approach. Hysteresis itself started to occur at 1.7%ΔTf above extinct temperature

scholarly journals Process Stability Identification Through Dynamic Study of Single-bed Ammonia Reactor with Feed-Effluent Heat Exchanger (FEHE)

2018 ◽  
Vol 156 ◽  
pp. 03003
Author(s):  
Tri Partono Adhi ◽  
Muhammad Iqbal Prasetyo
Keyword(s):  
Heat Exchanger ◽  
Exothermic Reaction ◽  
Reactor System ◽  
Hysteresis Phenomenon ◽  
Feed Stream ◽  
Process Stability ◽  
Aspen Hysys ◽  
System A ◽  
Feed Temperature ◽  
Hysteresis Phenomena

In ammonia reactor system, a feed-effluent heat exchanger (FEHE) is typically installed to utilize reaction-generated heat to heat the reactor’s feed. Utilizing energy from exothermic reaction to the incoming feed stream is often called “autothermic operation”. Despite the advantage of FEHE, there is a risk of utilizing FEHE in a reactor system such as instability of process temperature or known as hysteresis. Hysteresis phenomena in chemical process could cause operational problems, for example it could damage the integrity of the equipment’s material. This paper aims to evaluate the dynamic behavior of a single-bed ammonia reactor with FEHE, particularly to propose a way to prevent instability within the system. The dynamic simulation of the single-bed ammonia reactor with FEHE was performed with Aspen HYSYS v8.8. The result of the simulation result shows that hysteresis phenomenon in the ammonia reactor system occurs when the feed’s temperature is below a certain value. If the feed temperature reaches that value, the temperature of the reactor’s outlet oscillates. One of the solution to keep the feed temperature above that critical value is by installing a trim heater within the system. Based on the simulation, trim heater installation within the system is able to prevent hysteresis in the system evaluated.

Characteristics of Particulate Matter Emissions on Diesel Passenger Vehicles Fueled with GTL Based on Real-Road Operating Parameters

2012 ◽  
Vol 534 ◽  
pp. 253-260
Author(s):  
Di Ming Lou ◽  
Yi Zhou Zhao ◽  
Yuan Hu Zhi ◽  
Pi Qiang Tan ◽  
Yan Juan Zhu
Keyword(s):  
Particulate Matter ◽  
Particle Number ◽  
Emission Rate ◽  
Volume Ratio ◽  
Specific Power ◽  
Operating Parameters ◽  
Emission Characteristics ◽  
Mixture Ratio ◽  
Passenger Vehicles ◽  
Particulate Matter Emissions

An on-board experimental research was made on diesel passenger vehicles fueled with national IV diesel, gas-to-liquid (GTL) fuel and three other different volume ratio of mixed fuel (G10D90, G20D80, G50D50) about the regularity of Particulate Matter (PM) emission characteristics changing with velocity, acceleration and vehicle specific power (VSP). The experimental results show that: PM emission rate increases gradually with higher velocity; acceleration leads to the deterioration of emissions; curves concave at the point when VSP value equals zero. Moreover, the emission rate of particle number decreases 50% to 60% while that of particle mass decreases 30% to 45% when the volumetric mixture ratio of GTL fuel improves. It is obvious that GTL fuel improves the characteristics of PM emission significantly, making it one of the promising clean alternative fuel.

scholarly journals Ammonia converter Simulation and Optimization Based on an Innovative Correlation for (KP) Prediction

2021 ◽  
Vol 23 (12) ◽  
pp. 323-338
Author(s):  
Muhammad El-Gharbawy ◽  
◽  
Walaa Shehata ◽  
Fatima Gad ◽  
◽  
...  
Keyword(s):  
Flow Reactor ◽  
Ammonia Synthesis ◽  
Plug Flow ◽  
Simulation And Optimization ◽  
Aspen Hysys ◽  
Simulation Techniques ◽  
Suitable Form ◽  
Reactor Temperature ◽  
Reaction Rate Equation

In this paper, the simulation and optimization of an industrial ammonia synthesis reactor is illustrated. The converter under study is of a vertical design, equipped with three radial-flow catalyst beds with inter-stage cooling and two quenching points. For building the model, a modified kinetic equation of ammonia synthesis reaction, based on Temkin- Pyzhev equation and an innovative correlation for (KP) prediction, was developed in suitable form for the implementation in Aspen HYSYS plug flow reactor using the spreadsheet embedded in the software with the introduction of some invented simulation techniques. A new parameter, which is a function of (T, P and α), was introduced into the reaction rate equation to account for the variation of KP with pressure. The simulation model is able to describe the converter behavior with acceptable accuracy. A case study was done, using Aspen HYSYS Optimizer, illustrated the optimum reactor temperature profile, after 12 years of operation, to achieve maximum production. The result predicts an increase of 8 tons ammonia per day accompanied with an increase of steam production of 12 tons per day.

scholarly journals Solution Combustion Synthesis of Fe2O3-Based Catalyst for Ammonia Synthesis

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1027
Author(s):  
Binxiang Cai ◽  
Huazhang Liu ◽  
Wenfeng Han
Keyword(s):  
Combustion Synthesis ◽  
Reaction Rate ◽  
Ammonia Synthesis ◽  
Fixed Bed ◽  
Solution Combustion Synthesis ◽  
Fixed Bed Reactor ◽  
High Dispersion ◽  
Synthesis Reaction ◽  
Solution Combustion ◽  
Metal Nitrates

Fe2O3-based catalysts were prepared by solution combustion synthesis (SCS) with metal nitrates (Fe, K, Al, Ca) as the precursors and glycine as the fuel. The activities of catalysts were evaluated in terms of ammonia synthesis reaction rate in a fixed bed reactor similar to the industrial reactors. The results indicate that the precursor of catalyst prepared by SCS is Fe2O3 which facilitates the high dispersion of promoters to provide high activity. The catalysts exhibit higher activity for ammonia synthesis than that of traditional catalysts, and the reaction rate reaches 138.5 mmol g−1 h−1. Fe2O3 prepared by SCS could be favorable precursor for ammonia synthesis catalyst. The present study provides a pathway to prepare catalyst for ammonia synthesis.

scholarly journals Comparative Study on Fuel Gas Supply Systems for LNG Bunkering Using Carbon Dioxide and Glycol Water

2019 ◽  
Vol 7 (6) ◽  
pp. 184 ◽  
Author(s):  
Jungho Choi ◽  
Eun-Young Park
Keyword(s):  
Heat Exchanger ◽  
Water System ◽  
Specific Power ◽  
Fuel Gas ◽  
Aspen Hysys ◽  
Lng Fuel ◽  
Main Component ◽  
Supply Systems ◽  
Significant Attention ◽  
Gas Supply

Liquified natural gas (LNG) fuel has received significant attention as an affordable and highly efficient fuel option due to strengthened regulations on the sulfur content of bunker oil put in place by the International Maritime Organization. The main component of the LNG fuel gas supply system (FGSS) is the heat exchanger that provides adequate gas temperatures and pressures required by the engine, which also has a large machinery volume compared with other equipment. Due to the volume limitation, most FGSS have been applied to new shipbuilding only. To reduce the volume of the FGSS, CO2 was considered to serve as the replacement heat medium for conventionally used glycol water during LNG gasification. The specific power consumption (SPC) in the CO2 and glycol water system was optimized using the Aspen HYSYS thermodynamic modeler toward adjusting the temperature and pressure, and the resulting sizes were compared. This study demonstrated that the CO2 heat medium resulted in a 14% improvement in efficiency and a 7% reduction in heat exchanger size concluding that it was the most advantageous heat medium for the LNG regasification.

Effect of Mass Flow Rate of Inlet Gas on Holdup Mass of Solidcyclone Heat Exchanger

2014 ◽  
Vol 592-594 ◽  
pp. 1498-1502 ◽  
Author(s):  
T. Mothilal ◽  
K. Pitchandi
Keyword(s):  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Efficiency ◽  
Solid Particles ◽  
Operating Parameters ◽  
Water Removal ◽  
Solvent Recovery ◽  
Solid Feed Rate

Effect of mass flow rate of inlet gas on holdup mass in a high efficiency cyclone has been performed. Cyclone as heat transfer equipment may be used for drying, solidification, water removal, solvent recovery, sublimation, chemical reaction and oxidation. In all such cases, performance of cyclone depends on the surface area of the solid particles inside the cyclone. The holdup varies with the variation in operating parameters. This proposed work will present an effect of mass flow rate of inlet gas on cyclone heat exchanger and calculation of holdup mass by varying the mass flow rate of inlet gas, solid feed rate and diameter of the particle.

An Experimental Study on the Thermal Performance Evaluation of SCW Ground Heat Exchanger

2017 ◽  
Vol 25 (01) ◽  
pp. 1750006 ◽  
Author(s):  
Keun Sun Chang ◽  
Min Jun Kim ◽  
Young Jae Kim
Keyword(s):  
Thermal Conductivity ◽  
Performance Evaluation ◽  
Heat Exchanger ◽  
Effective Thermal Conductivity ◽  
Thermal Performance ◽  
Thermal Response ◽  
High Heat ◽  
Injection Rate ◽  
Operating Parameters ◽  
Ground Heat Exchanger

In recent years, application of the standing column well (SCW) ground heat exchanger (GHX) has been noticeably increased as a heat transfer mechanism of ground source heat pump (GSHP) systems with its high heat capacity and efficiency. Determination of the ground thermal properties is an important task for sizing and estimating cost of the GHX. In this study, an in situ thermal response test (TRT) is applied to the thermal performance evaluation of SCW. Two SCWs with different design configurations are installed in sequence to evaluate their effects on the thermal performance of SCW using a single borehole. A line source method is used to derive the effective thermal conductivity and borehole thermal resistance. Effects of operating parameters are also investigated including bleed, heat injection rate, flow rate and filler height. Results show that the effective thermal conductivity of top drawn SCW (Type A) is 11.7% higher than that of bottom drawn SCW (Type B) and of operating parameters tested bleed is the most significant one for the improvement of the thermal performance (40.4% enhanced in thermal conductivity with 10.9% bleed).

Membrane Distillation Desalination System With Gap Circulation and Cooling Using a Built-in Heat Exchanger

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Atia E. Khalifa
Keyword(s):  
Energy Consumption ◽  
Heat Exchanger ◽  
Specific Energy Consumption ◽  
Membrane Distillation ◽  
Operating Conditions ◽  
Water Desalination ◽  
Module Design ◽  
Membrane Surfaces ◽  
Best Value ◽  
Feed Temperature

Abstract A comprehensive experimental investigation is conducted to evaluate the performance of a new flux-enhanced compact water gap membrane distillation (WGMD) module design with gap circulation and cooling for water desalination. The new design uses a separate circulation loop to circulate the gap water, and a built-in heat exchanger coil implanted inside the coolant stream channel for cooling the circulated gap water. The WGMD modules with circulation and with circulation and cooling are compared with conventional WGMD without circulation. Variations of distillate flux, temperatures, and energy consumption are presented at different design operating conditions. Circulation and cooling of the gap water greatly enhance the output flux due to gap water motion and increase the temperature difference between membrane surfaces. However, the enhancement in flux was achieved at the expense of energy consumption. Circulation and cooling of gap water are more effective with bigger gap widths. Feed flowrate showed significant effects with gap water circulation and cooling. The electrical specific energy consumption (SEC) showed the best value of 7.9 and 8.8 kWh/m3 at a feed temperature of 70 °C for both conventional WGMD and WGMD with circulation modules, while the best value of SEC for the WGMD module with gap circulation and cooling was 9.4 kWh/m3 at a feed temperature of 80 °C.

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