Nurkholis Hamidi

Biogas Laminar Burning Velocity and Flammability Characteristics in Spark Ignited Premix Combustion

Spherically expanding flames propagating at constant pressure were employed to determine the laminar burning velocity and flammability characteristics of biogas-air mixtures in premixed combustion to uncover the fundamental flame propagation characteristics of a new alternative and renewable fuel. The results are compared with those from a methane-air flame. Biogas is a sustainable and renewable fuel that is produced in digestion facilities. The composition of biogas discussed in this paper consists of 66.4% methane, 30.6% carbon dioxide and 3% nitrogen. Burning velocity was measured at various equivalence ratios (ϕ) using a photographic technique in a high pressure fan-stirred bomb, the initial condition being at room temperature and atmospheric pressure. The flame for methane-air mixtures propagates from ϕ=0.6 till ϕ=1.3. The flame at ϕ≥1.4 does not propagate because the combustion reaction is quenched by the larger mass of fuel. At ϕ≤0.5, it does not propagate as well since the heat of reaction is insufficient to burn the mixtures. The flame for biogas-air mixtures propagates in a narrower range, that is from ϕ=0.6 to ϕ=1.2. Different from the methane flame, the biogas flame does not propagate at ϕ≥1.3 because the heat absorbed by inhibitors strengthens the quenching effect by the larger mass of fuel. As in the methane flame, the biogas flame at ϕ≤0.5 does not propagate. This shows that the effect of inhibitors in extremely lean mixtures is small. Compared to a methane-air mixture, the flammability characteristic (flammable region) of biogas becomes narrower in the presence of inhibitors (carbon dioxide and nitrogen) and the presence of inhibitors causes a reduction in the laminar burning velocity. The inhibitor gases work more effectively at rich mixtures because the rich biogas-air mixtures have a higher fraction of carbon dioxide and nitrogen components compared to the lean biogas-air mixtures.

Laminar Burning Velocity and Flammability Characteristics of Biogas in Spark Ignited Premix Combustion at Reduced Pressure

Biogas as a “Powergas” is an alternative fuel produced in digestion facilities, that is sustainable and renewable. Based on chemical analysis, the composition of the biogas produced in East Java is 66.4% methane, 30.6% carbon dioxide and 3% nitrogen. Methane is a flammable gas, whereas, nitrogen and carbon dioxide are inhibitors. Given it has a different composition to traditional fuels, a fundamental study of biogas flame propagation characteristics is desirable to quantify this important fuel property. Spherically expanding flames propagating at constant pressure are employed to measure the laminar burning velocity and flammability characteristics as mixture function of the mixture composition. These important parameters were measured using a photographic technique in a high pressure fan-stirred bomb. The characteristics of biogas-air flames were initially studied at reduced pressure and at various equivalence ratios from the lower flammable limit to the upper flammable limit. The results were compared with those from biogas-air flames at atmospheric pressure. Based on this experimental investigation, the laminar burning velocities of biogas-air mixtures at reduced pressure were 0.218 m/s for ϕ=0.75, 0.246 m/s for ϕ=0.80 and 0.269 m/s for ϕ=0.85 respectively and only for these biogas mixtures propagated at reduced pressure. At the same equivalence ratio (ϕ), the laminar burning velocities of the biogas-air mixtures at reduced pressure are higher than those at atmospheric pressure. The flammable region of biogas became narrower by reducing initial pressure. The dilution effect is stronger at reduced pressure. Therefore, the flammable composition mixture areas of biogas-air mixtures are more limited at reduced pressure than those at atmospheric pressure.

Seed Oil of Morinda citrifolia L. as a Surfactant for Deinking Flotation

Surfactants are essential in the pulp recovery process for the removal of ink on paper to be recycled. In order to create a “green” surfactant, seed oil was extracted from Morinda citrifolia L. by Soxhlet extraction for 4–8 h and its composition evaluated by gas chromatography-mass spectrometry (GC-MS). The total ion chromatogram (TIC) of fatty acids of Morinda citrifolia L. (FAMC) indicated that extraction yields the largest amount of unsaturated fatty acids (UFA), specifically C19H34O2 and C21H38O2, at 6 h. All FAMC fractions were evaluated for their suitability as a surfactant for deinking flotation. FAMC isolated after 6 h of extraction yields fatty acids that are the most suitable surfactants, as the fraction consists of mostly unsaturated fatty acids that show good interactions with the structure of common ink molecules. Our results show that the performance of the FAMC taken after 6 h of extraction approaches that of a synthetic surfactant (SS). The appropriate viscous force for deinking flotation was found to be 1.5–2.0 × 10−4 mg/mm s2 when the synthetic surfactant is used compared to 1.0–1.5 × 10−4 mg/mm s2 for FAMC. The higher intermolecular bonding strength in the synthetic surfactant-ink particle system requires higher viscous force.

Studi Numerik Pembakaran Butana (C4H10) dalam Meso Scale Combustor dengan Perforated Plate

This research was conducted to determine the combustion stability and flame temperature inside meso-scale combustor with variations of perforated plate flame holder and combustion gas temperature at combustor exit side using numerical method or Computational Fluid Dynamics (CFD). Meso-scale combustor is made of two pieces of quartz glass tube with a length of 20 mm and 10 mm. Each quartz glass tube having an internal diameter of 3.5 mm and a wall thickness of 0.7 mm. Two kinds of perforated plate flame holder made of copper i.e. perforated plate type I and perforated plate type II, inserted between two quartz glass tubes. Butane (C 4 H 10 ) and air were used in this study as fuel and oxidizer, respectively. Numerical simulations were performed using ANSYS Fluent 17.0. The result of numerical simulation showed that the most stable combustion is obtained in meso-scale combustor by using flame holder in the form of perforated plate type II at higher reactant velocity. In addition, the combustor with perforated plate flame holder type II also produces a higher flame temperature at the same reactant speed. These phenomena occured due to the temperature distribution into the reactans is more uniform and the recirculation heats into the reactans is better than the combustor with perforated plate flame holder type I. Flame and combustor walls temperatures increased with increasing recirculation heats.

The Role of Fatty Acids Functional Group in Morinda citrifolia L. on Surface Tension and Diffusion Performance into Ink Particles

Abstract The interaction of fatty acid of Morinda citrifolia L. (FAMC) with ink was studied using Hele Shaw Cells. The interaction is compared to that of fatty acid derivates of synthetic surfactant. These interactions are modeled and explained through micro diffusion and its viscous fingering character. The results show that the molecule structure and the number of double bonds have a special effect on the surface tension and the micro diffusion character. FAMC at six-hour extraction has the highest speed of interaction and highest perimeter of diffusion among synthetic surfactants and other fatty acids in Morinda citrifolia L.

A simulation for predicting potential cooling effect on LPG-fuelled vehicles

Liquefied Petroleum Gas vehicles (LPG Vehicles) provide a potential cooling effect about 430 kJ/kg LPG consumption. This cooling effect is obtained from the LPG phase change from liquid to vapor in the vaporizer. In the existing system, energy to evaporate LPG is obtained from the coolant which is circulated around the vaporizer. One advantage is that the LPG (70/30 propane / butane) when expanded from 8 bar to at 1.2 bar, the temperature is less than −25 °C. These conditions provide opportunities to evaporate LPG with ambient air flow, then produce a cooling effect for cooling car’s cabin. In this study, some LPG mix was investigated to determine the optimum condition. A simulation was carried out to estimate potential cooling effects of 2000 cc engine from 1000 rpm to 6000 rpm. In this case, the mass flow rate of LPG is a function of fuel consumption. The simulation result shows that the LPG (70/30 propane/butane) provide the greatest cooling effect compared with other mixtures. In conclusion, the 2000 cc engine fueled LPG at 3000 rpm provides potential cooling effect more than 1.3 kW, despite in the low engine speed (1000 rpm) only provides about 0.5 kW.Liquefied Petroleum Gas vehicles (LPG Vehicles) provide a potential cooling effect about 430 kJ/kg LPG consumption. This cooling effect is obtained from the LPG phase change from liquid to vapor in the vaporizer. In the existing system, energy to evaporate LPG is obtained from the coolant which is circulated around the vaporizer. One advantage is that the LPG (70/30 propane / butane) when expanded from 8 bar to at 1.2 bar, the temperature is less than −25 °C. These conditions provide opportunities to evaporate LPG with ambient air flow, then produce a cooling effect for cooling car’s cabin. In this study, some LPG mix was investigated to determine the optimum condition. A simulation was carried out to estimate potential cooling effects of 2000 cc engine from 1000 rpm to 6000 rpm. In this case, the mass flow rate of LPG is a function of fuel consumption. The simulation result shows that the LPG (70/30 propane/butane) provide the greatest cooling effect compared with other mixtures. In conclusion, the 2000 ...

Characteristic of flotation deinking using bio and synthetic surfactant at different air flow rate

Flotation deinking has industrially applied but several problems keep unsolved because limitations have to compete with several variables present. Flotation deinking is multi variables process, so studying flotation deinking is still interesting. In this research, the amount of variables was reduced and focused to the performance comparison between flotation deinking of old newspaper (ONP) using biodegradable fatty acid of morinda citrifolia as the raw bio surfactant (RBS) and biodegradable fatty acid of palm oil that had been converted to be commercial surfactant (CS). The flotation was done at laboratory flotation cell equipped with orifice at different diameter (orifice number 20, 40 and 60) with adjustable airflow rate. Brightness and Effective Residual Ink Concentration (ERIC) of the deinked pulp were measured. The best results were achieved on orifice number 40 with the highest brightness of 41.96 °ISO and 40.96 °ISO when using CS and RBS respectively, and lowest ERIC of 896.82 ppm and 1001.72 ppm w...

Study on propane-butane gas storage by hydrate technology

Different technology has been applied to store and transport gas fuel. In this work the storage of gas mixture of propane-butane by hydrate technology was studied. The investigation was done on the effect of crystallizer rotation speed on the formation of propane-butane hydrate. The hydrates were formed using crystallizer with rotation speed of 100, 200, and 300 rpm. The formation of gas hydrates was done at initial pressure of 3 bar and temperature of 274K. The results indicated that the higher rotation speed was found to increase the formation rate of propane-butane hydrate and improve the hydrates stability.

Study on Characteristics of Ricinoleic Acid as a Phase Change Material

Today the use of fatty acids as heat storage substance is growing. The use of several types of fatty acids such as oleic acid, palmitic acid, and stearic acid as heat storage materials has been studied. But, ricinoleic acid from castor oil has not been studied yet. This study was conducted to ascertain the characteristics of ricinoleic acid as a heat storage material.Methyl ricinoleic was obtained through transesterification of castor oil by methanol with sodium methoxide catalyst. Methyl ricinoleic was then hydrolyzed using sodium hydroxide in ethanol to produce ricinoleic acid. Ricinoleic acid was identified by FTIR (Fourier Transform Infrared Spectrophotometer) test standard ASTM E 1252-07 and its chemical composition was determined by Gas Chromatography-Mass Spectrometry (GC-MS). The identification of the type, amount, and environment of hydrogen in the compound was determined by Nuclear Magnetic Resonance (NMR). The analysis on characteristics, that is, transition and melting temperatures of material was performed by DSC (Differential Scanning Calorimetry) test standard ASTM D 3419-08.Based on the results of FTIR, GC-MS, 1H-NMR, dan 13C-NMR tests, the spectra that were obtained indicated that the test substances were methyl and ricinoleic acid 70.349%. And, the results of DSC tests indicated that the characteristics of ricinoleic acid absorbed and released latent heat at the temperature from 8.58°C and absorbed sensible heat at the temperature from-7.17°C to 8.58°C.

Rheology Margarine on Non-Newtonian Fluid Proving through Small Gap

Theory and principles of rheology can be used for, process control, product design and as a tool for prediction process if the process could not actually be measured. The purpose of this research is to find rheological properties of margarine in dough/non-newtonian fluid developed on two parallel flat acrylic separated by an infinitesimally small gap. The driving force of the development fluid is CO2 fermented yeast. Fluid driven and expands passed a small gap in various sizes. Development time and time to pass through the small gap measured. The samples are used are two, dough without addition of margarine and other. Experiments showed that fluid added by margarine would be easier to pass through small gap than other, characterized by shorter time to pass through the small gap.