Suhaimi Hassan

Torrefaction of empty fruit bunches under biomass combustion gas atmosphere

Torrefaction of oil palm empty fruit bunches (EFB) under combustion gas atmosphere was conducted in a batch reactor at 473, 523 and 573K in order to investigate the effect of real combustion gas on torrefaction behavior. The solid mass yield of torrefaction in combustion gas was smaller than that of torrefaction in nitrogen. This may be attributed to the decomposition enhancement effect by oxygen and carbon dioxide in combustion gas. Under combustion gas atmosphere, the solid yield for torrefaction of EFB became smaller as the temperature increased. The representative products of combustion gas torrefaction were carbon dioxide and carbon monoxide (gas phase) and water, phenol and acetic acid (liquid phase). By comparing torrefaction in combustion gas with torrefaction in nitrogen gas, it was found that combustion gas can be utilized as torrefaction gas to save energy and inert gas.

Effect of Combination Factors of Operating Pressure, Nozzle Diameter and Riser Height on Sprinkler Irrigation Uniformity

The irrigation uniformity of sprinkler irrigation system depends on many design factors such as nozzle type, nozzle diameter, operating pressure and riser height. An experimental study was performed to investigate the effect of combination factors of operating pressure, nozzle diameter and riser height on sprinkler irrigation uniformity. Different operating pressures, nozzle diameters and riser heights have been used. The irrigation uniformity coefficients such as coefficient of uniformity (CU) and distribution uniformity of low quarter (DUlq) have been studied. This study concluded that, the irrigation uniformity of sprinkler irrigation system was more affected by the combination of operating pressure, nozzle diameter and riser height.

Syngas Dual-Fuelling

Biomass can be converted into a useful source of energy through gasification. The gasification product, which is a mixture of different gases, is known as synthesis gas or syngas. The composition of syngas may fluctuate due to many factors such as operational errors of the gasifier as well as the type of feedstock used or may be due to the feeding rate fluctuation. Therefore it would be difficult to assess the effect of syngas composition and diesel replacement ratio to the performance and emission when combusted in a compression ignition engine. In order to overcome this problem, controllable compositions and conditions of imitated syngas were used in this study by selecting three compositions of syngas close to the real conditions. The objective of this study was to ascertain the possibility of using syngas as an alternative to diesel fuel for an internal combustion engine while providing acceptable engine performance and emission levels. The test results on syngas performance and emission are compared with the results for diesel at an engine speed of 1200, 2000, and 3000 rpm. The results of the performance test of both fuels are examined interms of the engine’s power output, exhaust temperature, brake specific fuel consumption, brake thermal efficiency, volumetric efficiency, and exhaust emission. A clear reduction in exhaust gas temperature is reported with syngas dual fuel operation reached up to 180°C with composition B at 1200 rpm and 51.1% diesel replacement ratio. A significant increase in the volumetric efficiency is reported with the addition of syngas. It reached up to 38% for composition C at 3000 rpm and 23.5% diesel replacement ratio. Composition A emitted the lowest value of carbon dioxide and nitrogen oxides at 1200 rpm which reached up to 1% and 108 ppm respectively.

Heat Absorption Properties Of Ground Material For Solar Chimney Power Plants

One of the major challenges to the widespread application of the solar chimney power plant is its low-power conversion efficiency because of the three technological processes involved. The chimney efficiency is difficult to improve, and thus enhancing the collector or turbine performance can considerably improve the total plant efficiency. This work focused on enhancing the energy conversion efficiency of the collector and also extending the operation time using a heat storage medium. The solar to thermal conversion and thermal storage capabilities of six ground materials that are potentially available in Malaysia were studied experimentally and numerically. The experimental model was designed such that the six materials were exposed to the same operation boundary conditions. The numerical studies were conducted using ANSYS software, where the geometrical models were developed and simulated using FLUENT for the fluid flow and energy/thermal field studies. The selected ground materials were ceramic, black stones, sawdust, dark-green painted wood, sand, and pebbles. The simulation and experimental results are in good agreement in terms of air stream velocity and energy conversion efficiency. The results showed that the different materials have different heat storage capacities, and that ceramics extend the operation with improved efficiency until nighttime. The results also showed that ceramic and black stones have better performance than the other materials. However, black stones are recommended as the absorbing material for solar chimney power plants in Malaysia and regional countries because they are readily available.

Numerical Analysis of Experimental Turbulent Forced Convection Heat Transfer for Nanofluid Flow in a Tube

A numerical model for determining the characteristics of flow and heat has been presented by modifying the eddy diffusivity equation of Sarma et al. The experimental data of thermo-physical properties determined using spherical particles in a wide range of concentration, particle size, materials and operating temperatures are available in the literature. The numerical analysis employed equations, which were developed using the experimental data of thermo-physical properties, friction factor and Nusselt number. Based on the agreement of the numerical results with the experimental data, the influence of concentration and temperature on the turbulent characteristics is presented. It is observed that SiO2 nanofluid attained higher velocity and lower eddy diffusivity compared to Cu nanofluid at a concentration. The temperature gradient increases with concentration and decreases with temperature.

Effect of Low Pressure on Irrigation Uniformity of Solid Set Sprinkler Irrigation System

The irrigation requires an efficient and effective method of water application to realize maximum return and conserve water resources. The low pressure sprinkler irrigation system is the most commonly used due to: its low energy cost, but the irrigation uniformity of this system is not constantly good because it is affecting by the design factors such as: nozzle type, nozzle diameter, operating pressure and spacing layout. But the most important factors are the operating pressure and nozzle diameter. In this study the effect of low pressure on the irrigation uniformity of the solid set sprinkler irrigation system was studied. Different low operating pressures (62, 82, 102 and122 kPa) were selected and different nozzle diameters (4, 5 and 7 mm) were used. The solid set layout was square (12 m between the sprinklers along the line and 12 m among the line). The catch-cans test was used to determine the uniformity coefficients such as: Christiansen’s coefficient of uniformity (CU), coefficient of variation (CV), distribution uniformity of low quarter (DUlq) and distribution uniformity of low half (DUlh). The distribution characteristics such as: throw radius and rotation speed were monitored. A comparison was made between the results obtained from different combination of operating pressures and nozzle diameters. The results of this study showed that, CU, DUlq and DUlh were increased when the pressure increased for all the nozzles. The greater values of CU, DUlq and DUlh were found with the combination of 7 mm nozzle diameter and 122 kPa. The coefficient of variation was increased when the pressure decreased for all the nozzles. The throw radius and rotation speed were increased gradually when the pressure increased. The throw radius was not significantly affected by the nozzle diameter while the rotation speed was more affected by the nozzle diameter.

Thermogravimetric Kinetic Behavior of Malaysian Poultry Processing Dewatered Sludge (PPDS) during Combustion

The combustion characteristic and kinetic analysis of Malaysian poultry processing dewatered sludge (PPDS) from two different origins, namely as PPDS 1 and PPDS 2 using Thermogravimetric analysis (TGA) were examined. The non-isothermal step was practiced under oxidative atmosphere during the investigation. The temperature was ramped from 30oC to 1000oC at four different heating rates to allow the calculation of kinetic analysis parameter i.e. activation energy. Derivative thermogravimetric (DTG) curves for both samples resulted from TGA shows 3 different peaks. Calculation of apparent activation energy was adopted using iso-conventional model free method. The different of activation energy value embedded in each samples was due to the non-similarity of its fuel characteristic and combustion behavior.

Small Scale Pilot Plant Thermal Dryer for Sewage Sludge Dewatering System – A Preliminary Study

Malaysia expected to face serious problem in sewage sludge disposal in the next few years if this problem is not properly manage and well treated. The common way of sludge disposal in Malaysia is to dispose it on the land, by landfill disposal. However, most of the landfill has been closed since reaching it capacity. This product required innovation and advance solution for treatment and disposal since the production of sewage sludge rapidly increasing and the available solution for their disposal is out dated .One of the ideal solution to dispose the sludge is by converting it into useful energy in the form of solid fuel such as pallet and briquette and burn it as a solid fuel to generate power. However, the main problem faced is it contains high moisture content which is more than 90% of moisture content. In order to convert it into useful energy, the moisture content of the sludge need to be reduced into acceptable level which is below 20% . One of the effective methods to remove the moisture content is by using a thermal dryer. The preliminary results from this study found that the thermal dryer produced 63.32kg/h of dried sewage sludge with moisture content less than 20% . The production rate of this dryer shows positive result and with continuous production, this dryer cable to dry tons of wet sewage sludge.

Experimental and Simulation Study on the Effects of Twisted Coil Plates on the Performance of Fire Tube Boiler

Influences of twisted coil plate insert on the performance of fire tube boiler using were experimentally investigated. In this study, the twisted coil plate was placed inside the tube to illustrate boiler performance. The performances of boiler were studied in terms of operating time taken, exhaust flue gas temperature, steam temperature and boiler efficiency. The boiler was operated with 50%, 100% and without tube coil plate inserts at low and high fire burner setting. Based on the results obtained, effect of twisted plate insert and without insert were observed. There is an enhancement in boiler performance in terms of boiler efficiency. The ANSYS Fluent simulation showed the effect of width ratio and twist ratio. Therefore, the experimental results indicate that using twisted coil plate in the boiler is one of the best ways to improve boiler performance.

Development of Thermal Insulation from Oil Palm Fiber for Chimney of Fire Tube Steam Packaged Boiler

In this study, an investigation was conducted to develop oil palm fiber from palm oil mill waste as a thermal insulator. The experimental study focused on comparisons of thermal conductivity and temperature gradient or difference between the existing commercial rockwool and the produced oil palm fiber as a thermal insulator for a chimney of steam packaged boiler. The experiments were conducted at different temperature ranges and packing density. The values of the measured thermal conductivity were found to be 0.02 W/m·K to 0.112 W/m·K for a packing density of 78, 96 and 112 kg/m3, and at a temperatures between 40 oC to 90 oC. The value of the thermal conductivity of the oil palm fiber showed an increase at higher temperatures and greater temperature gradient as compared to the rockwool insulator. Although not being able to match the values at higher temperatures and temperature difference, other factors such as the cost and the environmental benefits of using oil palm waste material should be taken into consideration and hence encouraging its use as at least a supplement to existing insulation materials.