Effects Of Inlet Air Temperature Research Articles

An experimental investigation into combustion and performance characteristics of an HCCI gasoline engine fueled with n-heptane, isopropanol and n-butanol fuel blends at different inlet air temperatures

An experimental study was conducted in a single cylinder, four stroke port injection Ricardo Hydra test engine in order to determine the effects of pure n-heptane, the blends of n-heptane and n-butanol fuels B20, B30, B40 (including 20%, 30%, 40% n-butanol and 80%, 70%, 60% n-heptane by vol. respectively) and the blends of n-heptane and isopropanol fuels P20, P30, P40 (including 20%, 30%, 40% isopropanol and 80%, 70%, 60% n-heptane by vol. respectively) on HCCI combustion. Combustion and performance characteristics of n-heptane, n-butanol and isopropanol were investigated at constant engine speed of 1500rpm and λ=2 in a HCCI engine. The effects of inlet air temperature were also examined on HCCI combustion. The test results showed that the start of combustion was advanced with the increasing of inlet air temperature for all test fuels. Start of combustion delayed with increasing percentage of n-butanol and isopropanol in the test fuels. Knocking combustion was seen with B20 and n-heptane test fuels. Minimum combustion duration was observed in case of using B40. Almost zero NO emissions were measured with test fuels apart from n-heptane and B20. The test results also showed that CO and HC emissions decreased with the increase of inlet air temperature for all test fuels. Isopropanol showed stronger resistance for knocking compared to n-butanol in HCCI combustion due to its higher octane number. It was determined that n-butanol was more advantageous according to isopropanol as thermal efficiency. As a result it was found that the HCCI operation range can be extended using high octane number alcohols away from knocking combustion and autoignition can be controlled.

Thermodynamic evaluation of gas compression station from the point of energy and exergy view with an approach to reduce energy consumptions and emissions: A case study

The objective of the present study is to evaluate the gas compression station installed in Marand city from the point of energy and exergy view with an approach to reduce energy consumptions and emissions. The use of exhaust gases thermal energy is investigated to produce steam and electrical power. This free extra electrical power can be used in electrical facilities of the gas turbine unit and the gas compression station can be independent from foreign electrical energy sources. Meanwhile replacement of existing gas turbine starting system and the effects of inlet air temperature, steam injection to the combustion chamber and the steam generator pinch point are studied on fuel consumption, net power production, nitrogen oxides emissions and irreversibilities in various loads. The results revealed that in the proposed gas compression station the produced electrical power from the generated steam in the minimum load and inlet air temperature of 288 K is more than the overall electrical energy consumptions. Steam injection with amount of 0.5 kg.s-1 to the combustion chamber increased the cycle efficiency from 34% to 37.5% and decreased the emission from 3.1 ppm to 0.45 ppm in full load condition.

Energy and exergoeconomic analysis of the gas compression station: A case study

The aim of this study is to improve the gas turbine operating conditions, used in the gas compression station of Marand, from the energy, exergy and economic points. The most important problems of these turbines are the low thermal efficiency due to the high heat losses, consuming large amounts of natural gas at the gas turbine start-up time in the starter system, turbine dependence on external electrical energy sources, as well as the high costs of fuel supply for the turbine and power consumption in auxiliary equipments. In this study the application of heat recovery steam generator to reduce the heat losses and increase the efficiency of combined cycle besides the replacement of the inefficient existing starting system are suggested. Furthermore, the effects of inlet air temperature, load, pinch point and steam injection to the turbine combustor are investigated in the energy and exergy balance equations and the unit exergy cost rates. Moreover, the costs related to the start up of a gas turbine, the fuel consumption and electrical energy are estimated. Results reveal that suggestive system not only can make the gas compression station independent from the external energy sources, but it also can reinforce the efficiency of the system and reduce the carrying costs. As with the 0.5 kg.s-1 steam injection to the combustion chamber of the gas turbine, at the inlet air temperature of 288 K and the pinch point of 10 K, the efficiency of the combined cycle increases 5 percent. Also the economic saving of this suggested system is about 79.68 dollars per each functional hour of the gas turbine and for the station running in its full load and design condition the amount of economic savings will exceed to 247 000 dollars in month.

Urea Hardness Optimization in a Fluidized Bed Coating Equipment Using Taguchi Design Method

This paper describes the use of Taguchi Method in optimizing coating hardness in a tangential fluidized bed coater using modified biopolymer. During the coating process, granular ureas collide among themselves and the wall surface at high velocity. This led to excessive attrition and likely to break the granular ureas into smaller sizes. Hence, hardness is the critical properties during operations such as packaging and stacking. A series of coating experiments were carried out by using the L9 orthogonal array with 3 levels to determine the effect of inlet air temperature (40, 60 and 80OC), disc rotation speed (40, 60 and 80 rpm) and spraying rate (0.5, 1.0 and 2.0 rpm) on hardness of coated granular urea. The optimized operating parameters in this work were 60OC for inlet air temperature, 60 rpm for disc rotation speed and 2 rpm for spraying rate. The results show that the spraying rate was the most significant factor affecting the hardness of the coated granular urea since the contribution was 69.2 %. No confirmations run for this work were necessary since the optimized operating parameters that were discovered was one of the experiments operating parameters.

Effect of inlet-air temperature on physico-chemical and sensory properties of spray-dried soy milk

Samples of spray-dried soy milk powder were produced at various spray-dryer inlet air temperatures and characterized. Soybean seed (Glycine max TAX 1448 – 2E Var.) was sorted, boiled for 40 min, manually dehulled, wet milled using plate mill and sieved with muslin cloth to obtain water soluble extract (soy milk). The soy milk was divided into two portions (samples A and B) and spray-dried using co-current spray dryer at a constant feed rate (20.5 ml/sec) but at air-inlet temperatures of 204oC and 260oC, respectively. Preliminary investigation carried out on this study showed that samples produced at air inlet temperatures below 200oC exhibited wet and agglomerated particles. The recovered powdered samples were analyzed for proximate composition, pH, available lysine, total solids, pack bulk density, viscosity, solubility and wettability at different reconstituting water temperatures, and sensory properties. Results showed that 38.60% and 45.55% yield (soy milk powder) were achieved at the end of the process for samples A and B respectively. The samples showed no significant differences (P ≥ 0.05) in some of these evaluated parameters such as fat, ash and pH. Soy milk powder showed high protein content (62.05±0.23%), fat (19.92±0.08%), ash (1.41±0.02 %) and available lysine (5.02±0.29%), but low carbohydrate content (12.85±0.01 %) and moisture (3.66±0.23%). The physical properties showed that the mean total solid of the samples was 10.33±0.33%, pack bulk density (0.57±0.00 g/ml), while the mean viscosity was 47 mpas. The sample spray-dried at 204oC had solubilities of 48% and 78% at reconstituting water temperatures of 40oC and 80oC, respectively while the sample produced at 260°C showed lower solubility of 38.46% and 45.01% when temperature of reconstitution were 40oC and 60oC, respectively. However, the sample produced at 260oC exhibited decreased solubility when the reconstituting water temperature was raised above 60oC. Its solubility was 40.39% at reconstituting water temperature of 70oC which further decreased to 38% at 80o C. The wettability of the samples steadily decreased as the reconstituting water temperature increased from 40 to 80oC. The wettability of the sample spray-dried at 204oC decreased from 36 to 22 sec, while that of sample spray-dried at 260oC decreased from 29 to 18 sec. Sensory scores showed that the sample spray-dried at 204oC was preferred to the sample spray-dried at 260oC.

Dynamic Behavior of Air Condition System and Temperature Control Analysis

A procedure for deriving a dynamic model of an air condition system was described in this paper. The system consisted of a zone, cooling coils and fan. Room thermal balance model and dynamic model of AC control system components including sensor, cooling coils and ducts, were established. This model accurately predicts the effect of inlet air temperature during closed loop control of output air temperature using chilled water flow rate as a control input. Fuzzy adaptive control (FAC) combined with proportional integral derivative (PID) control algorithms (FAC-PID) were used to control the chilled water flow rate. Computational simulations were carried out in toolbox Simulink of Matlab. The fuzzy parameters were carefully tuned to produce less oscillatory responses. The results show that the system based on FAC-PID control is capable of controlling the disturbance efficiently with less time lag and small error than PID control.

Optimization of Coating Thickness in a Tangential Fluidized Bed

The focal intention of this research was to investigate the factors influencing the coating thickness of urea granule by using modified biopolymer which performed in a tangential fluidized bed. The effects of inlet air temperature, disc rotation speed and spraying rate on coating thickness of urea granule were investigated. In this study, the results showed that the significant process parameters which effect the coating thickness was spraying rate (58.585%), followed by disc rotation speed (21.579%) and inlet air temperature (18.883%). The optimized process parameters in this work were 400C for inlet air temperature, 40 rpm for disc rotation speed and 2 rpm for spraying rate. The confirmation run for this work had verified the conclusion from the variance analysis.

Enhancement of exergy efficiency in combustion systems using flameless mode

An exergitic-based analysis of methane (CH4) conventional and flameless combustion in a lab-scale furnace is performed to determine the rate of pollutant formation and the effective potential of a given amount of fuel in the various combustion modes. The effects of inlet air temperature on exergy efficiency and pollutant formation of conventional combustion in various equivalence ratios are analyzed. The rate of exergy destruction in different conditions of flameless combustion (various equivalence ratios, oxygen concentration in the oxidizer and the effects of diluent) are computed using three-dimensional (3D) computational fluid dynamic (CFD). Fuel consumption reduction and exergy efficiency augmentation are the main positive consequences of using preheated air temperature in conventional combustion, however pollutants especially NOx formation increases dramatically. Low and moderate temperature inside the chamber conducts the flameless combustion system to low level pollutant formation. Fuel consumption and exergy destruction reduce drastically in flameless mode in comparison with conventional combustion. Exergy efficiency of conventional and flameless mode is 75% and 88% respectively in stoichiometric combustion. When CO2 is used for dilution of oxidizer, chemical exergy increases due to high CO2 concentration in the combustion products and exergy efficiency reduces around 2% compared to dilution with nitrogen (N2). Since the rate of irreversibilities in combustion systems is very high in combined heat and power (CHP) generation and other industries, application of flameless combustion could be effective in terms of pollutant formation mitigation and exergy efficiency augmentation.

Effect of Inlet Air Temperature on Liquid Fuel Combustion in Taper Can Gas Turbine Combustion Chamber

The influence of inlet air temperature on penetration, vaporization and combustion of atomized liquid fuel droplets which is sprayed in a stream of turbulent swirling air flow stream located inside taper can gas turbine combustion chamber has been simulated using the commercial Computational fluid dynamics code star CD. It was observed that the variation of inlet air temperature plays a significant role on penetration, vaporization and combustion. The results were presented with help of plot of average temperature and contour plots of turbulent kinetic energy.

CFD Simulation of Deep-Bed Paddy Drying Process and Performance

Computational Fluid Dynamics (CFD) was applied three-dimensionally to simulate the drying behavior of paddy in a deep-bed dryer. The commercial CFD software Fluent 6.3.26 was used. The deep-bed paddy drying process and performance were studied by incorporating user-defined function (UDF) in Fluent written in C language. The predicted drying parameters were compared with experimental data of deep-bed drying of paddy. The values of mean relative deviation (MRD), standard error of prediction (SEP), and maximum error of prediction (MEP) for prediction of grain moisture content, air temperature, and absolute humidity were less than 6, 10, and 9%; 0.33% (d.b), 1.24°C, and 0.06% (kg/kg of dry air); and 2.25% (d.b), 6.8°C, and 0.37% (kg/kg of dry air), respectively, which reflect reasonable accuracy. Moreover, the energetic and exergetic performance of deep-bed paddy drying were simulated and analyzed. The effects of inlet air temperature and mass flow rate on the performance parameters were investigated. It was shown that the application of higher levels of inlet air temperature and lower mass flow rates yielded higher exergy efficiencies of deep-bed paddy drying.

Microencapsulation of Anchovy (E ngraulis encrasicolus L.) Oil: Emulsion Characterization and Optimization by Response Surface Methodology

The aim of the present study was to evaluate the anchovy (Engraulis encrasicolus L.) oil emulsion characterization and to optimize the anchovy oil microencapsulation process by spray drying. Response surface methodology was employed to study the effects of inlet air temperature (160–190C), peristaltic pump rate (20–40%) and ratio of coating to oil (2/1–4/1) on the oil particle size, microencapsulation efficiency (MEE), peroxide value (PV), bulk density, Carr index (CI) and dry matter. The inlet air temperature showed a significant (P < 0.05) influence on the MEE, PV and CI of samples. The peristaltic pump rate and ratio of coating to oil affected significantly (P < 0.05) only the MEE and PV. The optimal drying condition for microencapsulation of anchovy oil was found as 164C the inlet air temperature, 25% the peristaltic pump rate and 4/1 the ratio of coating to oil. Practical Applications Anchovy fish (Engraulis encrasicolus L.) was succesfully encapsulated with gum arabic and maltodextrin. The response surface methodology (RSM) was employed to optimize the microencapsulation condition of anchovy oil. Inlet air temperature and ratio of coating to oil were found as the main independent variables.

Product characteristics and quality of bovine blood‐enriched dried vegetable paste

The aim of this study was to evaluate a preparation of vegetable paste with bovine blood in order to maximize the protein content using linear programming, and to analyze the product characteristics and quality of bovine blood-enriched vegetable paste dried in a spouted bed. The drying experiments were performed by evaluating the effects of inlet air temperature, paste flow rate and paste solids concentration on the dried product characteristics and quality (functional and nutritional properties). The vegetable paste enriched with bovine blood was a good source of protein (∼0.20 g g(-1) , dry basis), and the linear programming was adequate to select the constituents (carrot, onion, potato, kale, tomato, soybean oil and bovine blood) and optimize their quantities. The drying conditions of bovine blood-enriched vegetable paste in the spouted bed that gave the best product characteristics were an air temperature of 110 °C and a paste flow rate of 600 mL h(-1) with 0.07 g g(-1) solids concentration. The addition of bovine blood to vegetable paste by linear programming increased the protein content of the paste and improved its functional properties and digestibility. The powder obtained from the spouted bed drier showed suitable functional and nutritional properties and was also a good source of antioxidant compounds.

Energy and exergy evaluation of a multiple-PCM thermal storage unit for free cooling applications

Latent heat thermal storage (LHTS) is a technology that can help to reduce energy consumption for cooling applications, where the cold is stored in phase change materials (PCMs). Free cooling is a concept developed for air conditioning applications, in which coolness is collected from ambient air during night and released into the room during the hottest hours of the day. In this work, energy and exergy analyses are performed for a free cooling system using a LHTS unit employing multiple PCMs. The effects of inlet air temperature and air flow rate on the performance of the system are investigated. It is observed that the increase in exergy efficiency due to reducing inlet air temperature is more significant than effect from increasing the air flow rate during the charging process.

Optimization of spray drying conditions for lulo (Solanum quitoense L.) pulp

The spray drying of lulo was optimized by using the central composite design of the response surface methodology, to study the effect of inlet air temperature (120–180°C), arabic gum concentration (0–10% w/w), and maltodextrin DE16.5-19.5 concentration (0–10% w/w) on some product and process aspects. Arabic gum and maltodextrin, more than inlet air temperature, improved the product yield, reduced the hygroscopicity and the water content of the obtained powder, and contributed to the retention of its nutritive and functional properties through an increase in ascorbic acid, vitamin C, total phenol and total flavonoid content and antioxidant capacity. Significant (p<0.05) response surface models were obtained in every case, with the linear terms of solute concentration being the factors that affected the response variables most significantly. The overall optimum spray drying conditions for obtaining lulo powder were 125°C inlet air temperature, 3% (w/w) arabic gum, and 13.4% (w/w) maltodextrin DE16.5-19.5.

CFD Modeling and Experimental Study of a Spray Dryer Performance

Abstract The performance of a pilot-scale spray dryer is investigated experimentally and theoretically. The governing equations for flow field, heat and mass transfer, and particle trajectory are solved by applying computational fluid dynamics (CFD). The effects of inlet air temperature and initial particle diameter on the outlet humidity and particle residence time are examined. These parameters should be considered carefully in proper designing of spray dryers especially for the heat-sensitive products. The model is validated with an error of 5.5%.

Simulation of energetic- and exergetic performance of microwave-assisted fluidized bed drying of soybeans

The performance of microwave-assisted fluidized bed drying of soybeans was simulated (using a previously validated mathematical model) and analyzed based on the first- and second law of thermodynamics. The energy and exergy analysis were carried out for several drying conditions. The effects of inlet air temperature, microwave power density, bed thickness and inlet air velocity on the efficiencies and inefficiencies of drying process have been simulated and discussed. Generally, application of microwave energy during fluidized bed drying enhanced the exergy efficiency of drying process. However, the results showed that it was more efficient not to apply microwave energy at the first stage of fluidized bed drying process. The application of higher levels of drying air temperature led in higher exergy efficiencies. The values of mean relative deviations for the predictions of efficiencies and inefficiencies of drying process were less than 14%, compared with those calculated using experimental data.

Drying of High-Moisture Paddy Using a Combined Impinging Stream and Pneumatic Drying System

A system combining the principles of impinging stream drying and pneumatic drying (ISD-PD) for high-moisture paddy was developed to increase the energy efficiency of the drying process. The effects of inlet air temperature and paddy feed flow rate on the overall performance, in terms of the volumetric water evaporation rate and volumetric heat transfer coefficient, and energy consumption of the system were then investigated. The dried paddy quality in terms of the head rice yield and whiteness was also assessed. The results were compared with those obtained from a system consisting only of a pneumatic dryer. It was found that an increase in the inlet air temperature and paddy feed flow rate led to an increase in the volumetric water evaporation rate. The volumetric heat transfer coefficient varied insignificantly with the inlet air temperature but increased with the paddy feed flow rate. The moisture content of paddy was reduced from its original value by 6.6 to 9.7% (db) within a very short period of time. The mean residence time of the paddy was increased by 33 to 41% via the use of the ISD-PD system, leading to moisture reduction rates 55–166% higher than those for the pneumatic dryer. The head rice yield decreased with an increase in the inlet air temperature and paddy feed flow rate. On the other hand, the effects of inlet air temperature and paddy feed flow rate on whiteness was not significant.

Air-Suspension Fluidized-Bed Microencapsulation of Probiotics

In the present research, an air-suspension fluidized-bed technique for generation of core and shell microcapsules containing probiotic Lactobacillusparacasei cells was evaluated. The air-suspension process was performed in a Würster coater system with a bottom-spraying atomizer. In the first stage, a solution containing trehalose, maltodextrin, and probiotic cells was spray-coated onto and absorbed by the inert carrier microcrystalline cellulose to produce nonagglomerating dry coated particles with high probiotic cell viability (109 colony-forming units [cfu]/g particles). The effect of inlet air temperature, spray flow rate, solids concentration, cell concentration, and encapsulation formulation on survival was investigated. The inlet air temperature had the most pronounced effect; a 15°C increase in inlet air temperature led to a 250-fold decrease in survival percentage. There was no agglomeration of the coated adsorbed particles at spray flow rates of 1 to 3.5 mL/min. Spraycoating was performed with both laboratory- and pilot-scale Würster systems. Scaling up the equipment from the lab scale to the pilot scale did not affect cell survival percentage. Low solids concentration (<20%) and low probiotic cell concentration (6%) resulted in a fair survival percentage (35–40). Spraying a solution formulation of trehalose–maltodextrin with dextrose equivalent (DE) 3 at a 1:1 ratio provided the best protection in terms of cell viability during the spray-coating process as well during storage. Layering with ethylcellulose (ETHOCEL) provided some protection in a low acidic environment (12%); however, the nonuniform coating and cracks detected by scanning electron microscopy (SEM) imaging were the main reasons for the layering's relatively poor protection of the cells against humidity, oxygen, and acid environment.

A study of in situ fluid bed melt granulation using response surface methodology / Uporaba metodologije odgovornih površin za študij in situ granulacije s talinami v zvrtinčenih plasteh

The objective of this work was to investigate the influence of selected individual variables (binder content, inlet air temperature, and product endpoint temperature) of in situ fluid bed melt granulation on the granule particle size distribution and percentage of dissolved carvedilol using a three-factor, five-level circumscribed central composite design. Increased binder content had the effect of increasing the granule particle size and drug dissolution rate. The effect of inlet air temperature and product endpoint temperature was found to be more pronounced in case of granule particle size parameters. Within the studied intervals, the optimal quantity of binder as well as optimal process parameters were identified and validated using response surface methodology. Utilizing these optimal process and formulation parameters, successful scaling up of the fluid bed melt granulation process was carried out. Granule characteristics obtained at pilot scale are comparable to those obtained at laboratory scale.

Effects of inlet air temperature and spray rate of coating solution on quality attributes of turmeric extract coated rice using top-spray fluidized bed coating technique

The addition of natural antioxidants onto white rice kernel can improve its functionality. Curcuminoids that present in turmeric rhizomes possess high antioxidant activity and heat stability. The objective of this study was to investigate the effects of inlet air temperatures and spray rates of turmeric extract solution on quality attributes of the turmeric extract coated rice (TCR) using the top-spray fluidized bed coating technique. The experimental results have shown that inlet air temperature and spray rate of coating solution strongly affected the final moisture content and percentage of fissured kernel of TCR. Almost all of TCR kernels in the bed cracked when their final moisture content was lower than 11.8% wet basis. However, the head coated rice yield of fissured TCR slightly decreased from that of white rice. The color of TCR was uniform over the entire surface. Texture of cooked TCR insignificantly changed from that of uncoated sample. Increasing spray rate provided higher both total phenolic content (TPC) and total antioxidant capacity (TAC) whilst increasing inlet temperature yielded lower TPC but it did not affect TAC. Retentions of TPC and TAC of TCR after cooking remained higher than 90%.