Experiment and Investigation in Reducing Emission from an IC Engine by using Inlet Helical Roller

This research paper reports that in-cylinder flow formation in a combustion engine has a major influence on the combustion, emission and performance characteristics. Air and fuel enters the combustion chamber of an engine throughout the intake manifold with high velocity. So, it introduces a helical roller in the path of inlet stream of mixture. It achieved the swirl by using a component that could be easily integrated into any existing engines at low engine speed. The performance of the engine increases and completes the combustion, leads to reduced emissions and small change in volumetric efficiency. It is also proved that increased swirl movement introduces helical roller that helps the flame spread which used into constant heat transfer rate. This suggests to a new combustion technique that should be developed to yield improved primary combustion processes in-side the engine with significantly reduced exhaust gas emissions.

Penggunaan Makrozoobentos Dalam Penilaian Kualitas Perairan Sungai Inlet Danau Maninjau, Sumatera Barat

Danau Maninjau yang terletak di Provinsi Sumatera Barat telah ditetapkan sebagai salah satu danau prioritas nasional diantara 15 danau lainnya. Kondisi kualitas air Danau Maninjau salah satunya dipengaruhi oleh kondisi kualitas air dari sungai-sungai yang bermuara di danau tersebut. Penelitian ini bertujuan untuk mengetahui kondisi kualitas air sungai inlet Danau Maninjau dengan menggunakan bioindikator makrozoobentos. Penelitian dilakukan pada bulan Juni dan Agustus 2019 di empat sungai inlet Danau Maninjau yang meliputi Sungai Koto Kaciak, Kurambik, Kularian, dan Ranggeh Bayur. Pengambilan sampel makrozoobentos dilakukan di segmen hulu, tengah, dan hilir dengan menggunakan kick net pada substrat berbatu dan berpasir, serta pengeruk Ekman pada substrat berlumpur. Berdasarkan hasil penelitian, ditemukan makrozoobentos di keempat sungai inlet dengan kisaran 5-25 famili dan 4-10 ordo yang tergolong ke dalam delapan kelas meliputi Insekta, Clitellata, Malacostraca, Bivalvia, Gastropoda, Polychaeta, Hirudinea, dan Turbellaria. Hasil analisis korelasi Spearman antara metrik biologi dengan Water Quality Index (WQI) menunjukkan bahwa metrik SIGNAL, EPT, dan LQI memiliki korelasi yang sangat kuat dengan nilai r > 0,7 (p<0,01). Metrik SIGNAL dengan korelasi tertinggi (r = 0,752) menunjukkan kondisi perairan sungai inlet Danau Maninjau yang tercemar ringan hingga berat. Metrik SIGNAL, EPT, dan LQI dapat diaplikasikan untuk melengkapi penilaian parameter fisik kimiawi perairan sungai inlet Danau Maninjau. ABSTRACTLake Maninjau which is located in West Sumatra Province has been designated as one of the national priority lakes among 15 other lakes. Water quality conditions of Lake Maninjau is influenced by the condition of the water quality of the streams that flow into the lake. The present study aimed to determine the condition of the water quality of the inlet stream of Lake Maninjau by using macrozoobenthos as bioindicators. This study was conducted in June and August 2019 in four inlet streams of Lake Maninjau including the Koto Kaciak, Kurambik, Kularian, and Ranggeh Bayur streams. A sampling of macrozoobenthos was carried out in the upstream, middle, and downstream using Surber nets on rocky and sandy substrates, and Ekman Grab on muddy substrates. Based on the results of this study, macrozoobenthos were found in the four inlet streams with a range of 5-25 families and 4-10 orders and classified into eight classes including Insects, Clitellata, Malacostraca, Bivalvia, Gastropods, Polychaeta, Hirudinea, and Turbellaria. The results of the Spearman correlation analysis between biological metrics and the Water Quality Index (WQI) show that the SIGNAL, EPT, and LQI metrics have a very strong correlation with r values > 0.7 (p < 0.01). The SIGNAL metric has the highest correlation (r = 0.752) indicates the inlet streams of Lake Maninjau which are lightly to heavily polluted. Metrics of macrozoobenthos communities such as SIGNAL, EPT, and LQI can be applied to complete the assessment of the physicochemical parameters of inlet streams of Lake Maninjau

Modelling and Simulation of Acid Gas Absorption from Natural Gas by Amine Solution Using Aspen HYSYS

This work has been carried out to model and simulate a typical acid gas absorption process using Aspen HYSYS process simulator. The chemical components involved in the process development were water, methane, ethane, propane, higher alkanes, carbon dioxide, hydrogen sulphide, nitrogen and amines: monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA) and methyldiethanolamine (MDEA). The fluid package selected for the simulation before entering the simulation environment was Acid Gas – Chemical Solvents. In the simulation environment, the model was developed by picking an absorber from the Model Palette, placing it and assigning the input and the output streams involved before inputting the parameters required for model convergence. The carbon dioxide-rich feed gas was made to enter the absorber at the bottom inlet stream while the lean amine stream entered at the top inlet and showered down on the uprising gas thereby trapping the carbon dioxide molecules within the gas. The top product from the absorber was the treated gas while the amine solution and the trapped carbon dioxide left the absorber as the bottom product. Different simulations were run to investigate the performance of the amines under the same operating conditions. It was discovered that, of all the four amine solvents considered in this work for the removal of carbon dioxide by chemical absorption, MEA had the highest efficiency but would require more dehydration because it had the highest water content. DEA was also found to scrub the carbon dioxide down to acceptable levels. However, TEA and MDEA barely scrubbed any carbon dioxide under these conditions, as their carbon dioxide compositions were found to be unacceptable. The analyses of the results obtained from the simulations indicated that Aspen HYSYS can be used to study the process of acid gas absorption successfully.

Multiple Steady States in the Photocatalytic Reactor for Colored Compounds Degradation

The paper reports the occurrence of multiple steady-state zones in most of the constructions of fixed-bed photocatalytic reactors. Such a phenomenon has not been ever observed in a field of photocatalytic reactors. The simulation has been provided for a common case in a photocatalysis—the degradation of colored compounds. The mathematical model of the photocatalytic reactor with immobilized bed has been stated by a simple ideal mixing model (analogous to the CSTR model). The solution has been continued by the two parameters—the Damköhler number and the absorption coefficient related to the inlet stream concentration. Some branches of steady states include the limit point. The performed two-parametric continuation of the limit point showed the cusp bifurcation point. Besides the numerical simulation, the physical explanation of the observed phenomenon has been provided; the multiple steady-states occurrence is controlled by light absorption–reaction rate junction. When the reaction rate is limited by the light absorption, we can say that a light barrier occurs. The dynamical simulations show that when the process is operated in a field of multiple steady states, the overall reactor efficiency is related to the reactor set-up mode.

Optimization of Energy Consumption in the Process of Dehumidification of Natural Gas

In recent years, there has been a great tendency to optimize energy consumption in the oil and gas industry’s upstream and downstream equipment. One of the most energy-intensive processes in natural gas refineries is the condensate stabilization unit (gas condensate). The main bottlenecks of energy consumption in the old units are condensated stabilization (dehumidification with ethylene glycol), heater reboiler, and air coolers (air coolers). Therefore, much attention should be paid to these applications and electricity and steam consumption in this unit. In this study, a simulated model based on the Gachsaran gas refinery’s new layout has been developed. Optimization of this part of the existing process is preheating the inlet flow to the reboiler by adding a two-stage shell-tube heat exchanger. This reduces the amount of steam needed to evaporate the inlet stream to the end of the tower. On the other hand, by pre-cooling the inlet currents to the air conditioners, the amount of electricity consumed to reach the outlet flows’ the desired temperature would be reduced. The results show an attractive return on investment for the remediation plan, a reduction in energy demand, and an increase in the unit’s productivity.

Burning rate augmentation in solid fuel ramjets by swirling inlet air stream

The influence of the inlet swirling flow on the regression rate of the fuel in the combustion chamber of the solid fuel ramjet is investigated in this study using numerical simulations. The finite-volume solver of the compressible turbulent reacting flow is developed to study the flow field where the burning rate is computed using the conjugate heat transfer method for the solid fuel. The correlation is found for the maximum regression rate versus an imposed inlet swirl when the linear distribution of the circumferential velocity is applied at the inlet stream. Although the regression rate augmentation is considerable due to the swirling flow field in the combustor, it is shown that the swirl is effective if is applied near the shear layer of the backstep flow in the combustor. The modified swirler with short blades is suggested to be used in solid fuel ramjets to increase the regression rate of the fuel and improve the performance, but with lower pressure loss.

Influence of evaporating rate on two-phase expansion in the piston expander with cyclone separator

The trilateral flash cycle shows a greater potentiality in moderate to low grade heat utilization systems due to its potentiality of obtaining high exergy efficiency, compared to the conventional thermodynamic cycles such as the organic Rankine cycles and the Kalina cycle. The main difference between the trilateral flash cycle and the conventional thermodynamic cycles is that the superheated vapor expansion process is replaced by the two-phase expansion process. The two-phase expansion process actually consists of a flashing of the inlet stream into a vapor and a liquid phase. Most simulations assume an equilibrium model with an instantaneous flashing. Yet, the experiments of pool flashing indicate that there is a flash evaporating rate. The mechanism of this process still remains unclear. In this paper, the flash evaporating rate is introduced into the model of the two-phase expansion process in the reciprocating expander with a cyclone separator. As such, the obtained results reveal the influence of evaporating rate on the efficiency of the two-phase expander.

Dimensioning of vortex storm overflows

Vortex storm overflow is an interesting and useful technical solution, especially important in storm and combined sewage systems. However, there are no methods of this device dimensioning, which would be mathematically simple and properly precise physically. Such a method has been proposed in this paper, on the basis of investigations performed for the vortex separators and vortex flow controls. The essence of this method relies on the kinematic model of the velocity field and energy balance of the inflowing stream and dissipation. The procedure enables specialists to calculate the rise of the liquid free surface caused by the inlet stream energy and the hydraulic resistance of the bottom outlet. These mathematical relations are completed by two formulae: for the bottom ‘morning glory’ sink and for the upper overflow. The model has been positively verified during the laboratory measurements, so can be used during the technical dimensioning of the vortex storm overflows.

CONSTRUCTAL DESIGN APPLIED TO A FINNED CHANNEL UNDER FORCED CONVECTION FLOWS WITH DIFFERENT IMPOSED PRESSURE DROPS

This paper aims to numerically study the heat transfer in a two dimensional finned channel under laminar, incompressible and forced convective flow with adiabatic walls. The main purpose is to maximize the convection heat transfer by changing the fin’s dimensions by means of Constructal Design. Numerical computations are performed for different Bejan numbers ranging from 0.182 up to 18.2. For all simulations the Prandlt number is kept constant, Pr = 0.71. The fluid motion throughout the channel is caused by imposition of pressure difference between inlet/outlet surfaces. Concerning heat transfer, it is caused by the difference of temperature between the inlet stream of fluid and the heated fins placed at the channel surfaces. The first fin is positioned in the lower surface of the channel while the second one is placed in the upper one. The problem is submitted to three constraints, the channel area (H × L), area of two fins and occupancy areas for the fins. It is considered here that both fins have the same fraction area (ratio between the fins and occupancy areas) f = 0.2. The problem is submitted to three degrees of freedom: H/L (ratio between height and length of channel), H3/L3 and H4/L4 which represent the ratio between the height and length of the first and second fin, respectively. Here, the second fin remains unchanged, being its dimensions H4/L4 = 2.0, whereas the first one is free to modify its dimensions, H3/L3. The channel dimensions are also constant. The solutions are sought using the conservation equations of mass, momentum and energy being these ones discretized through the Finite Volume Method (FVM). Results showed the importance of Constructal Design application for thermal improvement of the problem. Thermal efficiency differences of 5 times where achieved when comparing the best and worst cases. Other important observation is concerned with the effect of ratio H3/L3 over heat transfer ratio (q) which varied significantly from a case where a pressure drop is imposed in the channel to other case where the driven force is caused by imposition of velocity field at the channel inlet.