Experimental and numerical analyses of flameless combustion using biogas from palm oil mill effluent

Flameless combustion as a clean combustion technology has been recently developed due to simultaneous low emission formation as well as efficient combustion process. Biogas has also recently been identified as a potential alternative fuel for flameless combustion. Biogas has attracted attentions because its generation is not limited to the specific geography. Since Malaysia is currently one of the world's largest producer of palm oil, biogas released from palm oil mill effluent (POME) has great capability to be applied as a source of energy in the country. Since the calorific value of POME biogas is relatively low (around 22 MJ/m3), producing a stable flame o f POME biogas premixed combustion is quite difficult. Indeed, high temperature of flame front and high rates of thermal NOx formation, complicated setting and low efficiency of the conventional biogas combustion are crucial problems in applying biogas in premixed combustion system. Since upgrading o f POME biogas is a complicated and expensive process, direct injection o f POME biogas in flameless combustion system is a candidate for efficient POME biogas energy extraction. The objectives of this study are to investigate performance o f a laboratory-scale flameless combustion furnace fuelled by POME biogas in terms of flameless stability, temperature distribution and pollutant formation. The effects of burner configuration on the performance of POME biogas flameless combustion are evaluated. Moreover, various aspects of biogas flameless mode in terms of burned gas recirculation inside the chamber and relationship between mixing and chemical reactions, effects of various preheated diluted oxidizer on the flameless combustion system are investigated numerically. The results confirm that flameless combustion of POME biogas is feasible in the lean, stoichiometry and rich fuel circumstances and the axial temperature of the chamber is higher in stoichiometric condition. Extremely low O2 and CH4 concentration are recorded in highly diluted oxidizer in ultra-lean flameless combustion. Due to the low calorific value of POME biogas and the distance between fiiel/oxidizer jets, Damkohler number is found higher than unity and consequently eddy dissipation method (EDM) is proposed for turbulence chemistry interaction of POME biogas flameless combustion. The numerical results are in good agreement with experimental results. The stability of POME biogas flameless combustion is discussed based on the internally burned gas recirculation. It is found that POME biogas flameless combustion is sustained when recirculation ratio (Kv) is greater than 2.6. Flameless combustion of POME biogas is found to be limited to Kv o f less than 4.6 in coaxial burner configuration. In tangential burner configuration, POME biogas flameless combustion is sustained in higher recirculation ratios (Kv =6.3). The efficiency o f POME biogas flameless combustion is 62% and 66% in coaxial and tangential burner configurations respectively. Temperature uniformity is calculated 0.92 and 0.96 in coaxial and tangential burner configurations respectively. When equivalence ratio increases from 0.6 to 1.2, NOx emission decreases from 2.4 ppm to less than 1 ppm in coaxial burner and from 3.1 ppm to 1.1 ppm in tangential burner

Editor in Chief’s Note on the Green Hydrogen Fuel from Solar / Wind Power

Renewable and sustainable energy has an evolving story as the ongoing trade war in the word is influencing crude oil prices. Moreover, the global warming is an inevitable consequence of the worldwide increasing rate of fossil fuel utilization which has persuaded the governments to invest on the clean and sustainable energy resources. In recent years, the cost of green energy has tumbled, making the price of renewables competitive to the fossil fuels. Although, the hydrogen fuel is still extremely expensive compared to the crude oil price, investigations about clean hydrogen fuel production and utilization has been developed significantly which demonstrate the importance of the hydrogen fuel in the future. This article aims to scrutinize the importance of green hydrogen fuel production from solar/wind energy

The Need to Label Genetically Modified Products from the Perspective of Community Health and Consumer Rights: A Review

Introduction: The production and supply of genetically modified organisms is one of the issues that have led to many legal, health and environmental issues. This research attempts to study the requirement for labeling of genetically modified products in terms of consumer rights and community health. Methods: This Review Article survey results researches during years from 2002 to 2016 with key word society health, genetic modified products, consumer rights, labeling at databases of Google scholar, SID, Iranmedex, Medline, PubMed, Springer, Science Direct, ProQuest, Magiran, MSRT journals system, Iran medical journals information system and ISC. Results: According to reported studies, genetically modified products may affect in human health, environment and society. Labeling of genetically modified products Cause to creating more awareness of consumer and provides informed choice of consumer. The responsibility of genetically modified products is Non-harmfulness is duty of producers and suppliers of genetically modified products.Conclusion: in line with protecting human and society health, According to consumer rights and environmental law and especially the precautionary principle, the labeling of genetically modified products is necessary

A Comparative Study of MCDM Methods Integrated with Rapid Visual Seismic Vulnerability Assessment of Existing RC Structures

Recently, the demand for residence and usage of urban infrastructure has been increased, thereby resulting in the elevation of risk levels of human lives over natural calamities. The occupancy demand has rapidly increased the construction rate, whereas the inadequate design of structures prone to more vulnerability. Buildings constructed before the development of seismic codes have an additional susceptibility to earthquake vibrations. The structural collapse causes an economic loss as well as setbacks for human lives. An application of different theoretical methods to analyze the structural behavior is expensive and time-consuming. Therefore, introducing a rapid vulnerability assessment method to check structural performances is necessary for future developments. The process, as mentioned earlier, is known as Rapid Visual Screening (RVS). This technique has been generated to identify, inventory, and screen structures that are potentially hazardous. Sometimes, poor construction quality does not provide some of the required parameters; in this case, the RVS process turns into a tedious scenario. Hence, to tackle such a situation, multiple-criteria decision-making (MCDM) methods for the seismic vulnerability assessment opens a new gateway. The different parameters required by RVS can be taken in MCDM. MCDM evaluates multiple conflicting criteria in decision making in several fields. This paper has aimed to bridge the gap between RVS and MCDM. Furthermore, to define the correlation between these techniques, implementation of the methodologies from Indian, Turkish, and Federal Emergency Management Agency (FEMA) codes has been done. The effects of seismic vulnerability of structures have been observed and compared

Utilization of biogas released from palm oil mill effluent for power generation using self-preheated reactor

In palm oil mills, for one ton crude palm oil (CPO) production, 70 m3 biogas is released from palm oil mill effluent (POME) which can endanger the environment. Palm oil mills without appropriate strategies for biogas collection can participate in greenhouse gases (GHGs) generation actively. In this paper, a typical palm oil mill with annual capacity of 300,000 ton oil palm production and 3 MW electricity demand is considered as a pilot plant and feasibility of power generation by POME biogas is modeled by Aspen Plus considering flameless mode in combustion system. A new design of lab-scale flameless reactor called self-preheated flameless combustion (SPFC) system is presented and employed in power generation modeling. In SPFC system, the flameless chamber is employed as a heater to preheat an oxidizer over the self-ignition temperature of the fuel. A helical stainless steel pipe (called self-preheating pipe) is installed inside the chamber to conduct the oxidizer from exhaust zone to the combustion zone inside the chamber and preheat oxidizer. In the flameless mode, the diluted oxidizer is injected to the helical pipe from the exhaust zone and the preheated oxidizer at the burner is conducted to the flameless furnace through a distributor. In SPFC system external heater for preheating oxidizer is removed and the rate of power generation increases. The results show that 10.8 MW power could be generated in ultra-lean POME biogas SPFC. However, the rate of pollutant especially CO2 and NOx is high in this circumstances. In stoichiometric condition, 4 MW power could be available in stable conditions with lower pollutant formation. Since, hydrogen is one of the ingredients of POME biogas, calculations confirm that the rate of power generation increases around 0.7 MW when just 2% hydrogen is added to biogas

Numerical Investigation of Head Frontal Velocity of nonconservative Dense Flows in Small Inclined Beds

Non-conservative dense flow frontal velocity has been simulated two dimensionally by fluent numerical code. The outcomes have been compared with experimental results. Numerical simulation was conducted as two-phase through Euler-Lagrange method. Reynolds-Stress Turbulent Model (RSM) with non-uniform grid and shredding mesh on the channel floor. The results obtained from numerical model of head frontal velocity show a good compliance with experiment results and greatly help analyzing the pattern of fluid movement in different scales

Numerical Investigation of Head Frontal Velocity of nonconservative Dense Flows in Small Inclined Beds

Non-conservative dense flow frontal velocity has been simulated two dimensionally by fluent numerical code. The outcomes have been compared with experimental results. Numerical simulation was conducted as two-phase through Euler-Lagrange method. Reynolds-Stress Turbulent Model (RSM) with non-uniform grid and shredding mesh on the channel floor. The results obtained from numerical model of head frontal velocity show a good compliance with experiment results and greatly help analyzing the pattern of fluid movement in different scales

Performance evaluation of palm oil-based biodiesel combustion in an oil burner

This paper presents an experimental investigation of the combustion characteristics of palm methyl ester (PME), also known as palm oil-based biodiesel, in an oil burner system. The performance of conventional diesel fuel (CDF) and various percentages of diesel blended with palm oil-based biodiesel is also studied to evaluate their performance. The performance of the various fuels is evaluated based on the temperature profile of the combustor's wall and emissions, such as nitrogen oxides (NOx) and carbon monoxide (CO). The combustion experiments were conducted using three different oil burner nozzles (1.25, 1.50 and 1.75 USgal/h) under lean (equivalence ratio (φ) = 0.8), stoichiometric (φ = 1) and rich fuel (φ = 1.2) ratio conditions. The results show that the rate of emission formation decreases as the volume percent of palm biodiesel in a blend increases. PME combustion tests present a lower temperature inside the chamber compared to CDF combustion. High rates of NOx formation occur under lean mixture conditions with the presence of high nitrogen and sufficient temperature, whereas high CO occurs for rich mixtures with low oxygen presence

An Experimental Investigation of Magnetized Water Effect on Formation Damage

In oil industries, water injection into oil reservoirs for pressure maintenance, oil displacement, and oil recovery is a common technique. Formation damage during water injection is a major problem in this process. Formation damage from the incompatibility of formation water (FW) and injection water (IW) causes a reduction in the permeability around the injection wells. Therefore, it is necessary that the formation damage be minimized using specific techniques such as the injection of scale inhibitors and water compatible with formation water. It has been proven that moving water through relatively weak magnetic field changes water properties. These changes involve density, electrical conductivity, salts dissolving ability, sedimentation rate of solid particles etc. This study was conducted to investigate the effect of magnetized water injection on the decline in rock permeability. Therefore, a magnetic field device was designed and combined with a formation damage setup. The results indicate that, in the presence of magnetic field, water injection causes less damage to rock, and the permeability reduction in this case is lower than when non-magnetized water is injected. In addition, the results show that a higher magnetic field flux reduces the permeability damage