Investigation Techniques of Arson Fire in Low-Temperature Warehouses Using ED-XRF

Investigation techniques for fire prevention in low-temperature warehouses were studied using energy dispersive X-ray fluorescence (ED-XRF). In the first experiment, a sample (galvanized steel sheet plus urethane foam plus sandwich panel) was burned with 500 mL of a flammable liquid (gasoline, thinner, kerosene, and light oil)/ Then, the component change of the sample was measured. In the combustion experiment, there was a difference in the heat of combustion depending on the type of flammable liquid; however, as a result of measuring the component change of the sample with ED-XRF after combustion, the largest component change was measured in the combustion experiment with gasoline. The change was in the order of thinner, kerosene, and diesel. Using ED-XRF, it was possible to distinguish the flammable liquid used in the experiment by measuring the component change of the sample resulting from the difference in the combustion heat of the flammable liquid. A second experiment was conducted under the same conditions as the first experiment, assuming a fire brigade fire suppression condition, and the combustion time of the flammable liquid was limited to 600 s. A combustion characteristic of flammable liquids is that the temperature and heat flux reach the maximum value within 300 s after the start of combustion regardless of the type of liquid. Because the change of composition was confirmed in the order of light oil, it was possible to distinguish the flammable liquid used at the fire site using the ED-XRF measurement result.

Influence of Mixture Composition and Compaction Pressure of Briquette Made from Ironwood (Eusideroxylon Zwageri) Charcoal and Gelam (Melaleuca Cajuputi ) on Combustion Characteristic

<p class="02abstracttext">In recent few years, many works have been dedicated to search for new source of renewable energy. In this study, new source of renewable energy is based in the briquette made from mixture of ironwood (Eusideroxylon zwageri) powder and gelam (Melaleuca leucadendron) wood powder. The mixture was carbonized at temperature of 500 ^oC ± 10 ^oC for 120 minutes. The size of the particles used was 50 mesh while the ratio between wood powder adhesives, i.e. starch powder, used in the study was 1:1. The composition variations between ironwood charcoal and gelam were 100% ironwood charcoal powder and 0% gelam, 70%: 30%, 50%: 50%, 30%: 70%, 0% ironwood: 100% gelam. The compaction pressure during briquette production was varied at 100 kg/cm², 125 kg/cm² and 150 kg/cm². The highest combustion temperature at 205 ^oC occurred in the specimen with composition of 30% ironwood powder and 70% gelam wood powder with compaction pressure of 100 kg/cm². The longest burning duration 140 minutes (2 hours 20 minutes) occurred at composition of 50% ironwood powder and 50% gelam wood powder at compaction pressure of 150 kg/cm². The fastest initial ignition time was 7 minutes and occurred for mixture with composition of 70% ironwood powder and 30% gelam wood powder at compaction pressure of 125 kg/cm².</p>

Combustion Characteristics and Kinetic Analysis of Biomass Pellet Fuel Using Thermogravimetric Analysis

Biomass pellet fuel is one of the development directions of renewable energy. The purpose of the article is to study the combustion characteristics of five kinds of biomass pellet fuel that can be used as biomass fuel and analyze their combustion kinetics. The thermogravimetric method (TG method) was used to analyze the combustion characteristics of five kinds of biomass pellet fuel and to calculate the index S of comprehensive combustion characteristic. The Arrhenius equation and the Coats–Redfern method were used to analyze the combustion kinetics of five kinds of biomass pellet fuel. The activation energy and pre-exponential factor were obtained according to different temperature ranges. Conclusions are as follows: The pyrolysis of five kinds of biomass pellet fuel mainly includes three stages: (1) water evaporation stage, (2) volatile component combustion stage, (3) fixed carbon oxidation stage. The TG curves of five kinds of biomass pellet fuel are roughly the same at the same heating rate. The peaks of thermal weight loss rate and maximum degradation rate are both in the high temperature range. The differential thermal gravity(DTG) curves of five kinds of biomass pellet fuel have an obvious peak. The peak temperature of the largest peak in the DTG curves is 280–310 °C. The first-order reaction equation is used to obtain the kinetic parameters in stages. The correlation coefficients are bigger than the value of 0.92. The fitting results are in good agreement with the experimental results. The activation energy of each sample is basically the same in each stage. The value in the volatile matter combustion stage is 56–542kJ/mol, and the activation energy of the carbon layer slowly increases rapidly. The five kinds of biomass pellet fuels have good combustion characteristics and kinetic characteristics, and they can be promoted and applied as biomass pellet fuels in the future.

The Effect of Biomass Shapes on Combustion Characteristic in Updraft Chamber

Combustion of agricultural residues and wastes for energy applications is still popular. However, combustion of biomass with different shapes leads to many side effects such as agglomeration, emission and incomplete combustion. The aim of this study was therefore to investigate the effects of biomass shapes on combustion characteristics in an updraft combustion chamber. The rubber wood chip, coconut shell, oil palm empty fruit bunch, corn straw, rubber wood sawdust, and mixed palm cake were used as fuel and they were categorized as 3 shapes namely, chip shape, fiber shape, and powder shape. The biomass sample was combusted in simple cylindrical shape combustion chamber. The diameter of combustion chamber was 20 cm and its height was 160 cm. The biomass sample (moisture content below 20%) with amount of 1 kg was used to perform the experiment. The ambient air that had velocity of 0.50, 0.75 and 1.00 m/s (corresponding to an equivalence ratio of 1-3.5) was supplied to combustion chamber. The temperature at different positions along combustion chamber height and the properties of flue gases (carbon monoxide) were then measured. The results showed that the biomass shape had effect on combustion characteristics. Combustion of fiber shape biomass led to low combustion temperature, while the carbon monoxide in flue gases was high. This indicates the improper combustion process. The chip shape biomass was well combusted at a higher air velocity and the flue gases had lowest carbon monoxide. The highest combustion temperature was obtained from combustion of powder shape biomass. However, it led to the problem of unburned biomass such in case of sawdust. This is because the sawdust powder was carried from combustion chamber before burning completely.