Emrah Özahi

Gaziantep University · Department of Mechanical Engineering

In this paper, municipal solid waste (MSW) based electricity production and district heating (DH) potential of Turkey are considered. Three MSW based waste-to-energy (WtE) scenarios is developed: (i) Scenario-I, a DH system integrated into a gas turbine power plant (GTPP), (ii) Scenario-II, a DH system integrated into an organic Rankine cycle (ORC)...

A thermodynamic comparison of five developed power cycles which are gas turbine (GT), Kalina (KAL), organic Rankine (ORC), gas turbine-Kalina (GT-KAL) and gas turbine-organic Rankine (GT-ORC) fed by the waste heat of an actual power plant system in Gaziantep is presented in this paper. The waste heat has a temperature and a pressure of 566 °C and 1...

In this paper, thermodynamic and thermoeconomic analysis as well as genetic algorithm optimization of two combined cycles, a gas turbine-organic Rankine cycle (GT-ORC) and a gas turbine-Kalina cycle (GT-KAL) are carried out. The novelty of this study is that the cycles are adapted to an actual solid waste power plant to generate additional power fr...

A municipal solid waste power plant located in Malatya, Turkey has been analyzed thermodynamically and thermoeconomically in this study. The sanitary landfill plant was constructed with an installed power capacity of 2.4 MW for both disposals of municipal solid waste and energy production from produced landfill gas (LFG) of 9425 m 3 , corresponding...

In this paper thermodynamic and thermoeconomic analyses and even optimization of a Kalina cycle (KC) which is adapted to an actual solid waste power plant with a 5.66 MW installed capacity are presented as an alternative solution which is utilized to produce additional power from the exhaust gas of the plant. Up to now there is almost no study rela...

The amount of methane emission is rapidly increasing while increasing of municipal solid waste production in landfills due to enormous growth in human population. This emission is supposed to be the third-largest human-generated source in global warming concept. Therefore, disposal of methane inside landfill gas is also an important phenomenon as w...

Biodegradable wastes are becoming a serious problem in terms of health and ecological balance in parallel with the increasing of local and global populations in recent years. These wastes should be disposed in both efficient and eco-friendly ways. Considering biodegradable wastes as an energy source, it is necessary to be sure that those disposal m...

Bu çalışmada, Organik Rankine Çevrimi (ORÇ) entegre edilmiş süperkritik CO2'nin (S-CO2) aracı akışkan olarak kullanıldığı bir gaz türbin çevrimi modeli gerçekleştirilmiştir. Sistemin termodinamik analizleri ASPEN Plus ve EES programları kullanılarak yapılmıştır. Termodinamik analizler sonucunda, önerilen sistemin elektrik üretim kapasitesi, enerji...

The amount of methane emission is rapidly increasing while increasing of municipal solid waste production in landfills due to enormous growth in human population. This emission is supposed to be the third-largest human-generated source in global warming concept. Therefore, disposal of methane inside landfill gas is also an important phenomenon as w...

Anaerobic digestion can be announced as a biological decomposition of organic materials by means of many kinds of microorganisms in the absence of oxygen in order to produce biogas. The main products of anaerobic digestion process are methane and carbon dioxide with the byproducts of water vapor, ammonia and hydrogen sulfide. Although production is...

In this paper, two different combined systems of GT-ORC and GT-KAL cycle were compared in terms of thermoeconomic aspects in order to produce additional electrical power to the actual power plant. GT-ORC and GT-Kalina cycle were designed by adding ORC and KAL to the GT system, respectively. The net power output of GT-ORC and GT-KAL cycle were evalu...

A thermodynamic comparison of three developed scenarios which are re-compression gas turbine cycle (GT), Kalina cycle (KAL) and organic Rankine cycle (ORC) which adapted to a municipal solid waste power plant system in Gaziantep is presented in this paper. Operation of the municipal solid waste power plant was described in detail and developed scen...

This paper presents thermodynamic and thermoeconomic analyses as well as optimization of a re-compression supercritical CO2 cycle. A gas turbine cycle (GT) is adapted as a model to an existing plant to generate additional power in Gaziantep Municipal Solid Waste Power Plant (GMSWPP). The total capital cost rate and total cost rate of the GT cycle a...

This paper presents a thermoeconomic analysis and assessment of a municipal solid waste power plant system in Gaziantep. The operation of an existing municipal solid waste power plant is described in detail and a thermoeconomical methodology based on exergoeconomic relations and specific exergy costing (SPECO) method is provided to allocate cost fl...

This paper presents the energy and exergy analyses of some different organic fluids which can be used in an organic Rankine cycle adapted to a municipal solid waste power plant in the frame of energy recovery. The novelty of the study is to adapt a well-known organic Rankine cycle system theoretically to the existing municipal solid waste power pla...

The main function of a sewage treatment is to minimize the harmful effects that the sewage water will give to the natural water environment in which it is discharged. The most energy-consuming process in a sewage treatment is the stabilization of the wastewater sludge. Despite high energy consumption, sewage sludge has the potential to become a ren...

Closed cycle gas turbine power generation systems have a significant potential to produce power. They have lost their first-time popularitywhen compared with more efficient open cycle gas turbines, which is related to higher firing temperature. Nevertheless in the recent past, closed cycle gas turbines become popular again as an alternative energy...

In this study, two interconnected systems using biogas and stabilized sewage sludge, which are important by-products of an actual municipal wastewater treatment system, are compared in terms of environmental impacts. In the first system, biogas produced from sewage sludge by anaerobic digestion is burned in an internal combustion gas engine driven...

In this study, pressure drop variations through six different pipe fittings for steady pipe flow in Reynolds number range of 1225<Re<9570 were investigated. A pipe fitting is generally used in pipeline systems to connect pipes together, to provide fluid flowing through different sizes and for other purposes, such as regulating or measuring fluid fl...

It is possible to increase the efficiency of a system by decreasing the exergetic losses. In this study, energy and exergy analyses are carried out for a coal-fired thermal power plant in İzmir for screening the system efficiency and proposing how the efficiency of the plant can be increased. Thermal Power plant has 250 MW installed power which is...

This paper presents energy and exergy analyses of a closed-cycle gas turbine using transcritical CO2 (T-CO2). The gas turbine (GT) system is developed in order to decrease the temperature of the exhaust gas at 347.8 oC in Gaziantep Municipal Solid Waste (MSW) Power Plant and also produce additional power from the plant. In this designed model, the...

In this study, five models are considered for the use of biogas-based electricity and sewage sludge obtained from a municipal wastewater treatment plant for green hydrogen production. These models include alkaline, PEM, high temperature water electrolysis, alkaline hydrogen sulfide electrolysis and dark fermentation biohydrogen production processes...

HVAC systems in buildings are composed of many subcomponents which consume energy in huge amounts. In recent years, energy consumption becomes very important aspect due to the lack of energy resources and environmental reasons. In terms of energy consumption, the components of HVAC systems account for large portion of total energy used in buildings...

The interactive influences of oscillation frequency and velocity amplitude ratio on onset of transition in pulsatile pipe flow are investigated experimentally in the ranges of time-averaged and oscillating Reynolds numbers of 1019±35⩽ ⩽4817±164 and 107±4⩽ ⩽4261±145 with velocity amplitude ratio of 0.05±0.0017⩽ ⩽0.96±0.03 for 227 runs. Oscillation f...

This paper presents a comparative life cycle assessment (LCA) of an existing digested sewage sludge incineration for heat and power production. Operations of an existing sewage sludge incineration plant based on a fluidized bed combustor (FBC) and a hypothetical cement kiln (CK) facility using sludge as a secondary fuel are described in detail as t...

This paper presents the thermoeconomic analysis and assessment of a municipal solid waste power plant system in Gaziantep. Operation of an existing municipal solid waste power plant is described in detail and a thermoeconomical methodology based on exergoeconomic relations and the specific exergy costing (SPECO) method is provided to allocate cost...

This paper presents the energy and exergy analyses of the different organic fluids which can be used in an organic Rankine cycle (ORC) adapted to a municipal solid waste power plant in the frame of energy recovery. It is known that, in a typical municipal solid waste power plant, a considerable amount of energy is sent up from a plant chimney to th...

Electrolysis Biohydrogen Wastewater treatment plant Biogas a b s t r a c t Five models were developed for the use of biogas-based electricity and sewage sludge obtained from a municipal wastewater treatment plant for hydrogen production. These models included alkaline, PEM, high temperature water electrolysis, alkaline hydrogen sulfide electrolysis...

Municipal solid waste landfill has been benefited as an alternative fuel and a renewable power source in recent years. Landfill gas (LFG) contains mostly methane and carbon dioxide, both of which are greenhouse gases that contribute to global warming. Generally, LFG to electricity technology is established in worldwide. Internal combustion engines...

The definition of the sub-classes in sinusoidal pulsatile pipe flow at the onset of transition to turbulence is given through the analyses of the velocity and the frictional field measurements conducted. For this reason, a systematic experimental study was carried out and the validation of the results was compared with those available in the litera...

A batch type fluidized bed dryer is designed and constructed in order to investigate drying performance of a batch type fluidized bed drying process of corn and unshelled pistachio nut regarding to energetic and exergetic efficiencies. A series of experiments is carried out for the purpose in the covered range of 100 g⩽ mp ⩽300 g, 50 °C⩽ T ⩽75 °C,...

This paper presents an automated generation, control, data acquisition and processing of sinusoidal pulsatile pipe flow using a devised program in LabView 2009SP1 (R) in the experimental ranges of the time-averaged Reynolds number, Re-ta, of 1019+/-35 <= Re-ta <= 4817+/-164, the oscillating Reynolds number, Re-os of 107+/-4 <= Re-oc <= 4261+/-145,...

Fluidized bed drying process is one of the most frequently used and successful methods in food,pharmaceutical and chemical industries due to its higher efficiency. For this reason, many studies in lab- and industry-scales are carried out on fluidized bed drying concept for improvements of their performance characteristics. A batch type fluidized be...

This paper presents the general overview of municipal solid waste (MSW) management in Turkey and especially in Gaziantep. The types and the used methods of MSW management are introduced and the comparisons of these management types are carried out worldwide. The updated portrait of energy demand in Gaziantep is also outlined. The portion of waste-t...

This paper gives the hardware and software of a test rig with its experimental procedure, methodology and uncertainty analyses of measurements for batch type fluidized bed drying of corn and unshelled pistachio nut. The test rig is designed, constructed and operated for the analyses of drying performance of corn and unshelled pistachio nut in a bat...

An original model for thermodynamic analysis of a batch type fluidized bed dryer is proposed herein considering two separate systems comprised of drying air medium as a control volume and particles to be dried as a control mass. By means of the proposed model, energetic and exergetic analyses of a drying column of a batch type fluidized bed dryer a...

This paper reports the results of an experimental study which has been carried out in order to perform the frictional and flow field analyses of the sinusoidal pulsatile pipe flow in laminar regime and at onset of transition. Herein the frictional field analysis is presented. The flow resistance in terms of time-averaged pressure drop and time-aver...

An experimental setup which is going to be used in order to investigate the drying performance of a batch type fluidized bed dryer for some harvested foods under varying drying temperatures and velocities is introduced in this paper. This study also presents a correlation study in which the drying performances of batch type fluidized bed drying pro...

Batch type fluidized bed drying is one of the most used and successful methods in food, pharmaceutical and chemical industries due to its higher efficiency. For this reason, many studies in lab- and industry-scales are continued on fluidized bed drying concept for improvements of their performance characteristics. This paper reports the recent sign...

This paper presents a program devised in LabView 2009SP1 (R) for the detection of the transition onset in laminar pulsatile pipe flows. As a conclusion of a comprehensive literature survey, it is deduced that there is no well-defined detection program even a methodology for determination of transition onset besides of conventional methods of visual...

Transition to turbulence in axially symmetrical laminar pipe flows with periodic time dependence classified as pure oscillating and pulsatile (pulsating) ones is the concern of the paper. The current state of art on the transitional characteristics of pulsatile and oscillating pipe flows is introduced with a particular attention to the utilized ter...

In this paper based upon the review of the related literature; the utilized terminology regarding the available types of absorption refrigeration systems; ARS, is outlined. The specified parameters used through experimental and theoretical studies are presented. In conformity with the related literature a single stage ideal ARS cycle with a solutio...

An experimental study conducted on pulsatile pressure and velocity measurements inside a sinusoidal air flow medium is presented. Controlled oscillation frequency, f and velocity amplitude ratio, A 1 are satisfied via so called mass flow control (MFC) unit. Velocity and pressure data through the signals of hotwire anemometer and pressure transmitte...

Pulsatile air flow in the form of a sinusoidal wave generated inside a rigid pipe of diameter D=26.6 mm is the medium considered. The frequency and the velocity amplitude ratio, f and 1 A , are the major controlling parameters having the respective ranges of 0.1 Hz≤ f ≤14 Hz and 0.05±0.0017≤ 1 A ≤ 0.96±0.03. The generation and control of flow is de...

Pneumatic conveying systems are used widely to convey different types of materials in a variety of industrial settings. The knowledge on flow modes is particularly important in the design stage of pneumatic conveying lines in terms of energy requirements. There are some classifications of flow modes valid for both powders and bulk solid particles b...

In the case of pneumatic particle transport lines; modelling of gas-solid two phase flow which has an unsteady and complicated non-linear dynamical nature is commonly used. In this paper; the concept of time-periodic; pulsatile pipe flow which is a special unsteady field is discussed as a possible control and modelling tool. The state of art is int...

The available studies conducted on the prediction of pressure drop in low velocity dense phase pneumatic conveying are generally based on steady state analyses. However, some experimental and numerical studies show that the flow mechanics in dense phase pneumatic conveying have time-dominate effects. An attempt for investigation of several mechanis...

Flow field measurements behind pipe entrance inserts called as flow conditioners in a mean flow Reynolds number range 547 <= Re <= 9000 are presented herein. A tube bundle, a Laws' perforated plate and an etoile were located at the entrance of a smooth circular pipe of inner diameter, D = 26.6 mm. The covered ranges of open area ratio, beta and non...

This paper presents two calibration methods for a CTA probe valid at low speeds covering a range of 0.029m/s≤U≤1.79m/s. The well-known in situ calibration method using a simple laminar pipe-flow set-up was used for a mean Re number range of 25≤Re≤1590. The rotating disc method is the proposed calibration method in the speed range of 0.05m/s≤U≤1.05m...

Despite the presence of a variety of studies dealing with the magnitude of particle Reynolds number, Rep defining transition from laminar to turbulent regime for flow through packed beds, the manner is still one of the unknowns. An approach based on the experimental data concerning upward airflow through fixed cylindrical packed beds is presented i...

Transition from laminar to turbulent flow in a pipe is one of the oldest and most fundamental problems in fluid mechanics. This phenomenon for time-dependent flows has been investigated by many researchers experimentally, analytically and numerically since the last century. However it is still an open research area for researchers. In most of the e...

An experimental study was conducted on the pressure drop characteristics of a variety of vertical packed beds in turbulent flow of air. The materials of different particle diameter, Dp, with a range of sphericity Φ, 0.55≤Φ≤1.00 were used in random loose packing to produce beds of different lengths, L, with a range of porosity, ε, 0.36≤ε≤0.56. In th...

An experimental study was conducted to determine the pressure drop characteristics of cylindrical packed beds through which turbulent pipe flow was passing. This study was planned to clarify the applicability of the well-known Ergun correlation proposed for beds composed with spherical particles on beds with non-spherical particles. The experimenta...