Mohammad Nazri Mohd. Jaafar

Removal of NOx and CO from a burner system

This paper presents the development of an emissions-controlling technique for oil burners aimed especially to reduce oxides of nitrogen (NOx). Another emission of interest is carbon monoxide (CO). In this research, a liquid fuel burner is used. In the first part, five different radial air swirler blade angles, 30 degrees , 40 degrees , 45 degrees , 50 degrees , and 60 degrees , respectively, have been investigated using a combustor with 163 mm inside diameter and 280 mm length. Tests were conducted using kerosene as fuel. Fuel was injected at the back plate of the swirler outlet. The swirler blade angles and equivalence ratios were varied. A NOx reduction of more than 28% and CO emissions reduction of more than 40% were achieved for blade angle of 60 degrees compared to the 30 degrees blade angle. The second part of this paper presents the insertion of an orifice plate at the exit plane of the air swirler outlet. Three different orifice plate diameters of 35, 40, and 45 mm were used with a 45 degrees radial air swirler vane angle. The fuel flow rates and orifice plates sizes were varied. NOx reduction of more than 30% and CO emissions reduction of more than 25% were obtained using the 25 mm diameter orifice plate compared to the test configuration without the orifice plate. The last part of this paper presents tests conducted using the air-staging method. An industrial oil burner system was investigated using the air staging method in order to reduce emission, especially NOx. Emissions reduction of 30% and 16.7% were obtained for NOx and CO emissions, respectively, when using air staging compared to the non-air-staging tests.

CFD ANALYSIS OF INCOMPRESSIBLE TURBULENT SWIRLING FLOW THROUGH ZANKER PLATE

Abstract Zanker plate is a widely used flow straightener to eliminate turbulence originating from pipe fittings in experimental fluid flow applications. In this paper, steady state, incompressible, swirling turbulent flow through Zanker plate has been studied. The solution and the analysis were carried out using finite volume CFD solver FLUENT 6.2. Five turbulence models were used in the numerical investigation and their results were compared with the pressure drop correlation of BS EN ISO 5167–2:2003. The turbulence models investigated here are the standard k-ε, realizable k-ε, the Reynolds Stress Model (RSM), the large Eddy Simulation (LES), and the Detached Eddy Simulation (DES). The results showed that the DES model gave the best agreement with the ISO pressure drop correlation, therefore, the model was used further to predict streamline patterns, vortex formations and separated flow regions. The effects of Zanker plate thickness and Reynolds number on the flow characteristics have been investigated as well.

Thermodynamic modeling and exergy optimization of a gas Turbine power plant

Due to the importance of increasing power plants performance in Iran Exergy analysis is a common way for these cycles, Thus For this analysis first each part of gas Turbine Plant were modeled by thermodynamic approach then The effect of changing in the inlet turbine temperature on the exergy efficiency and exergy destruction in this plant was evaluated. The results show that the exergy efficiency of the combustion chamber is much lower than that of other plant components due to chemical reaction and the large temperature difference between the burners and working fluid. In addition, these calculations are performed for 50 and 75% G.T base load and results show that the exergy destruction when G.T work in base load is more than full load. More ever the optimizations process has been follow in this paper, therefore in this regard the economic objective function has been defined and minimized.

Combustion Performance Evaluation of Air Staging of Palm Oil Blends

The problems of global warming and the unstable price of petroleum oils have led to a race to develop environmentally friendly biofuels, such as palm oil or ethanol derived from corn and sugar cane. Biofuels are a potential replacement for fossil fuel, since they are renewable and environmentally friendly. This paper evaluates the combustion performance and emission characteristics of Refined, Bleached, and Deodorized Palm Oil (RBDPO)/diesel blends B5, B10, B15, B20, and B25 by volume, using an industrial oil burner with and without secondary air. Wall temperature profiles along the combustion chamber axis were measured using a series of thermocouples fitted axially on the combustion chamber wall, and emissions released were measured using a gas analyzer. The results show that RBDPO blend B25 produced the maximum emission reduction of 56.9% of CO, 74.7% of NOx, 68.5% of SO(2), and 77.5% of UHC compared to petroleum diesel, while air staging (secondary air) in most cases reduces the emissions further. However, increasing concentrations of RBDPO in the blends also reduced the energy released from the combustion. The maximum wall temperature reduction was 62.7% for B25 at the exit of the combustion chamber.

Optimization of the esterification process of crude jatropha oil (CJO) containing high levels of free fatty acids: a Malaysian case study

ABSTRACT Biodiesel as an alternative fuel is one of the best choices among other sources due to its immense potential to reduce pollutant emissions when used in compression ignition engines. Malaysia is considered one of the top biodiesel-producing countries. The main crop for biodiesel production is currently palm oil. However, Jatropha curcas has recently drawn the attention of the Malaysian government as an alternate species for producing high yields of oil. While an evaluation of biodiesel production, blending, engine performance and emissions characteristics of Malaysian-produced jatropha methyl ester has been made recently, few studies have optimized the esterification of the crude oil. This paper is the study of an optimization process for Malaysian CJO using an acid-catalyst pretreatment process to reduce the relatively high free fatty acid (FFA) percentages of crude jatropha oil to below 1% using design of experiments and response surface methodology, with the help of Minitab software. The main findings of the current investigation are that using the acid catalyst H2SO4 at 0.225% (v/v), an MeOH-to-oil ratio of 12.29% (w/w) and a reaction time of 149.76 min are the optimum process parameters for the esterification reaction.

Experimental and numerical studies of swirl combustion characteristics of syngas

Synthesis gas (syngas) is a potential clean fuel for gas turbine. Experiments and numerical simulations were conducted to study the combustion characteristics of syngases in premixed swirl mode using a model gas turbine swirl burner. Four different types of syngases, covering low to high H2-content were tested. Experimental work was conducted to study the emission performance of lean swirl flame. Obtained results were used as validation targets for numerical simulation using flamelet generated manifold (FGM) and chemical equilibrium (CE) approaches. The former method shows better agreement with experimental result, hence FGM method was adopted to model flame structure and predict emission species in the reaction zones for different syngas types. Result shows that syngas with high concentration of H2 produces lower peak flame temperature and height. Furthermore, high H2-rich syngas also produces low level of NO species in the reaction zone.

Effects of air compressor pressure ratio on exergy efficiency, cost and environment of a Combined Cycle Power Plant

This work covers energy and exergy, and exergoeconomic and environmental of a Combined Cycle Power Plant (CCPP). To assess the effects of air compressor pressure ratio on efficiency, economic and environment of the system a parametric study is performed. To have reasonable results, the air compressor pressure ratio is varied while all other design parameters are kept constant. Results show by increasing the air compressor pressure ratio the exergy efficiency of gas cycle is increased while the total efficiency is reduced. Consequence, the total cost and CO2 emission are increased.

Energy Analysis and Multi-Objective Optimization of an Internal Combustion Engine-Based CHP System for Heat Recovery

A comprehensive thermodynamic study is conducted of a diesel based Combined Heat and Power (CHP) system, based on a diesel engine and an Organic Rankine Cycle (ORC). Present research covers both energy and exergy analyses along with a multi-objective optimization. In order to determine the irreversibilities in each component of the CHP system and assess the system performance, a complete parametric study is performed to investigate the effects of major design parameters and operating conditions on the system’s performance. The main contribution of the current research study is to conduct both exergy and multi-objective optimization of a system using different working fluid for low-grade heat recovery. In order to conduct the evolutionary based optimization, two objective functions are considered in the optimization; namely the system exergy efficiency, and the total cost rate of the system, which is a combination of the cost associated with environmental impact and the purchase cost of each component. Therefore, in the optimization approach, the overall cycle exergy efficiency is maximized satisfying several constraints while the total cost rate of the system is minimized. To provide a better understanding of the system under study, the Pareto frontier is shown for multi-objective optimization and also an equation is derived to fit the optimized point. In addition, a closed form relationship between exergy efficiency and total cost rate is derived.

The Influence of Orifice Insertion for Low Noxious Emissions from Combustion System

This paper presents the effect of inserting swirler outlet orifice plate of different sizes at the exit plane of the radial air swirler in liquid fuel burner system. Tests were carried out with three different orifice plates with area ratios (orifice area to swirler exit area ratio) between 0.7 and 1.0 using 280 mm inside diameter combustor of 1000 mm length. Several tests were conducted using the commercial diesel as fuel. The fuel was injected at the back plate of the 45o vane angle swirler outlet using a central fuel injector with a single fuel nozzle pointing axially outwards. The aim of the insertion of orifice plates is to create the swirler pressure loss at the swirler outlet phase in order to maximise the swirler outlet shear layer turbulence to assist the fuel/air mixing. In the present work, the orifice plate with smaller area ratios exhibited very low NOX emissions for the whole operating equivalence ratios. The NOX reduction of more than 20 percent is achieved for orifice with 0.7 area ratio compared to 1.0 area ratio. Other emission such as carbon monoxide is increased with the decrease in the orifice area ratios. The results from this experiment show that good combustion is achieved by using smallest area ratios of orifice plate.

Numerical Investigation of Combustion Performance Utilizing Envo-Diesel Blends

Alternative fuel and renewable energy is needed to fulfill the energy demand of the world. The use of envo-diesel fuels for power generation seems a viable solution for the problems of decreasing fossil-fuel reserves and environmental concerns. The use of envo-diesel in gas turbines would extend this application to power generation field. Envo-diesel is considered as better option because of its environmental friendly characteristics while giving almost the same functional properties like a fossil fuels. The gas turbine combustion performance that utilizes palm envo-diesel fuel is investigated. This study is to perform a detailed simulation of combustion and thermal flow behaviors inside the combustor. The simulations are conducted using the commercial Computational Fluid Dynamics (CFD) package software to determine the spray flames and combustion characteristics of commercial diesel fuel, envo-E5 and envo-E10. The diameter and temperature of the fuel droplets; and temperature contour, mass fraction of diesel and mass fraction of carbon dioxide (CO2) of the combustor were obtained for commercial diesel fuel, envo-E5 and envo-E10. Diesel fuel displayed higher rates of droplet evaporation compared to E5 and E10 with SMD differential about 30 to 40 μm while mass fraction for E5 and E10 slightly lower than conventional diesel.