Exhaust Gas System Research Articles

IDENTIFICATION OF INDUCED DRAFT FAN (IDF) DAMAGE IN BOILER WASTE GAS SYSTEM

Induced Draft Fan (IDF) is a fan that sucks air from inside the boiler out to the chimney, producing negative pressure on the boiler, keeping the circulation of combustion air in the boiler normal. IDF is one of the main components in the exhaust gas system which serves to maintain the temperature and vacuum of the furnace in the boiler. This report will identify IDF damage using vibration indication control instruments by looking at vibration indication trending data through the Distributed Control System (DCS) in the Central Control Room (CCR). The results of the trending data will then be identified whether the vibration in Induced Draft Fan has increased, if the vibration ≥ 5.6 mm/s is declared an alarm and if the vibration ≥ 7.1 mm/s then the unit trip or must be stopped. Based on the results of research during industrial practice in Banten 2 PLTU Labuan there were 2 conditions in the IDF, namely when there was a disturbance with a height of X and Y side vibrations of 22.5 mm/s, and conditions after improvement with the height of X vibration side that is, an average of 4.2 mm/s and Y side averaging 4.1 mm/s. The high vibration is affected by the damage of several IDF components, caused by the amount of ash remaining combustion that enters the IDF which causes abrasion of the impeller blade.

Difference in the Tailpipe Particle Number by Consideration of Sub-23-nm Particles for Different Injection Settings of a GDI Engine

The purpose of this study was to investigate the characteristic of nanoparticles under consideration of sub-23-nm particles from a 1.8-l direct injection (DI) gasoline engine under stoichiometric air/fuel conditions in the exhaust gas system. For future CO2 challenges, the usage of DI—instead of port fuel injection (PFI)—gasoline engines is unavoidable. Therefore, a state of the art particle management program-particle number (PN) system, the Horiba SPCS (2100) with an integrated CPC (condensation particle counter), was recalibrated from a 50% cutoff (D50%) at 23 nm down to a cutoff at 10 nm and the PCRF (particle concentration reduction factor) for sizes smaller than 23 nm was checked. Two different modal points, out of a representative Real Driving Emission (RDE) cycle, were investigated with both calibrations, D50% = 10 nm and D50% = 23 nm. For these different load points, the fuel pressure (FUP) and the start of injection (SOI) were varied, to represent the difference in the structure and the ratio conc(10 nm)/conc(23 nm) of the nanoparticle emissions. The particle characterization includes the particle number (PN), the particle size distribution (PSD), and the particle mass (PM). The particle number was measured with Horiba SPCS (2100). The particle size distribution was analyzed with a Grimm differential mobility analyzer (DMA) in combination with a Faraday cup electrometer (FCE). Micro Soot and Pegasor were used to determine the PM, and an optical characterization was done with a 120-kV Phillips CM12 transmission electron microscope (TEM). The position of all particle measurement systems was downstream the three-way catalyst (TWC). The results of this investigation showed that a higher injection pressure decreases the PN (without consideration of sub-23-nm particles) in general. The ratio conc(10 nm)/conc(23 nm) was therefore higher, because smaller particles, especially ash particles, were less reduced from the FUP. This means higher FUP tends to a higher ratio. For the SOI, the main reasons of the ratio differences were explained by an encroachment between the injection jet and the piston, the valve and the wall.

Improving the Gas-Exhaust System at Foundry Electrofurnaces

Abstract—Inspection of the gas-exhaust system at arc furnaces of capacity 3–10 t in the casting shops of manufacturing enterprises reveals problems responsible for copious gas and dust emissions in the production buildings, with degradation of the air quality. This is mainly associated with structural shortcomings of the systems for gas and dust evacuation from the furnace chamber through the exhaust channel, working window, and gaps between the housing and roof and also between the edges of the holes in the upper section and the electrodes within the holes. In particular, the moving joints between the rotary hoods and the gas-exhaust lines in such systems do not ensure reliable sealing. Accordingly, an improved design of the hood-rotation mechanisms has been proposed, with two sand barriers preventing the atmospheric emission of harmful emissions between the moving components. In the design of an industrial prototype, a method is developed for calculating the energy parameters of the drive in the improved system. A 1 : 10 scale model of the system is built to check the design and the theoretical equations. By means of a measuring system consisting of a tensoresistive converter, an ac amplifier, an analog–digital converter, and a computer, the load on the model’s drive on switching from the working position to the rest position and back is determined, for two cases: with and without sand barriers to seal the mobile components. The drag in the two sand barriers on rotation of the moving element amounts to 20–26% of the total load on the drive, depending on the angular velocity of the cantilever with the hood. According to the theoretical formulas, this figure is 17–23% for hood-rotation mechanisms in arc furnaces of capacity 3–10 t. Video recordings of the smoke fluxes from the model through the gaps between its housing and the roof during simulations of steel production confirm the reliability of the sand barriers, which ensure complete sealing of joints in the hood-rotation mechanism. Practical use of the proposed design improves gas–dust evacuation from the working zone of smelting furnaces used in the foundry.

Innovative Combustion System for Economic and Ecological Thermal Utilization of Solid Fuel in Heating Boilers

AbstractAn innovative combustion system, the so‐called low‐emission combustion system (LEVS), with integrated exhaust gas treatment measurement for thermal utilization of biomass‐fueled boilers is presented. It comprises an intelligently controlled three‐fan combustion air supply and exhaust gas system, a cyclone combustion chamber, and packed‐technology, ensuring high combustion efficiency and stable low‐emission combustion. The technology was tested by preliminary experiments for various application scenarios of biomass, and the current environmental and health‐related aspects were also evaluated. The relevant emission reduction through the system results from improved combustion in critical operating phases, in which the total emissions produced in conventional gasification boilers are drastically reduced. A minimum increase of the boiler efficiency of 15 % in practice with corresponding fuel and CO2 savings can be guaranteed.

Impact of Ni Content on the Thermoelectric Properties of Half-Heusler Thermoelectrics

Motivated by high peak zT values reported 13 years ago for the (Ti,Zr,Hf)NiSn Half-Heusler system, Half-Heusler materials are identified as a promising materials class for thermoelectric applications. We investigate the TiNiSn sub-system, which does not rely on expensive Hf. From phase boundary mapping, we find that the thermoelectric TiNiSn Half-Heusler phase shows a narrow solubility range on the Ti-Ni-Sn phase diagram primarily in the range of excess Ni that can be approximated as TiNi1+xSn, where x is temperature dependent with 0 ≤ x ≤ 0.06 at 1223 K. Four phase boundary compositions with different Ni contents associated with four three-phase regions are identified. We characterize the thermoelectric properties of these stable compositions and find significant difference between Ni-rich and Ni-poor phase boundary compositions of TiNiSn, which amounts up to 41%, 58%, and 25% difference in Seebeck coefficient, lattice thermal conductivity, and thermoelectric figure of merit respectively. This explains the large discrepancy of literature data on the thermoelectric properties of TiNiSn within a unified phase diagram framework. We demonstrate that Ni-rich TiNiSn results in a narrower band gap using the Goldsmid formula, which we interpret to be due to the formation of an impurity band from interstitial Ni in the forbidden gap as previously suggested. Interstitial Ni atoms scatter both electrons and phonons, with the latter effect being much stronger, thus a lower lattice thermal conductivity compensates the decrease in electron mobility leading to a high zT value of 0.6 at 850 K for intrinsic Ni-rich TiNiSn. With Sb doping, the carrier concentration in these stable boundary compositions can be tuned but the distinct features in their transport properties remain unchanged. A maximum zT value of 0.6 was also achieved at 850 K for intrinsic Ni-poor TiNiSn upon Sb doping. We further present results on the integration of n-type TiNiSn Half-Heusler material into 36-legs modules in conjunction with p-type FeTiNb Half-Heusler material including their multi-physics modelling-assisted matching and integration into a heat exchanger mounted and tested in the exhaust gas system of a compact van. Y. Tang, X. Li, L.H.J. Martin, E. Cuervo Reyes, T. Ivas, C. Leinenbach, S. Anand, M. Peters, G.J. Snyder, C. Battaglia, Energy & Environmental Science, 2018, 11, 311 D. Landmann, Y. Tang, D. Widner, R. Huber, P. Rickhaus, R. Widmer, C. Battaglia, in preparation

Aging Effects of Catalytic Converters in Diesel Exhaust Gas Systems and Their Influence on Real Driving NOx Emissions for Urban Buses

Aging Effects of Catalytic Converters in Diesel Exhaust Gas Systems and Their Influence on Real Driving NO_x Emissions for Urban Buses

A reduced model for the evaporation and decomposition of urea–water solution droplets

Selective catalytic reduction with urea–water-solution is commonly used in the automotive sector to reduce nitric oxide emissions. Detailed modelling of the exhaust gas system in front of the catalyst can help in optimizing this process. Such simulations include many different physical effects and chemistry on strongly differing spatial and time scales, thus require a high amount of computational reserves. Therefore, simplified or reduced models are needed to describe some of the processes which can then be added in the overall simulation. To develop reduced models the evaporation and decomposition of a droplet of urea–water-solution and the corresponding gas phase chemistry in hot exhaust gas are analysed using detailed simulations. It is shown that the process can be separated into three main phases, namely water evaporation, urea decomposition and reactions in the gas phase, which, for the conditions considered, do not significantly couple with each other. For the first two phases a simple model is developed, which calculates the mass and energy source term for a droplet evaporation process depending only on temperature and water content of the surrounding exhaust gas and the initial diameter of the droplet. The time scales and entropy production of the gas phase chemistry are determined for typical gas mixture compositions and initial conditions and based on these results a skeletal mechanism for chemical kinetics is generated. It can describe the gas phase chemistry for temperatures up to 800 K. In addition, it is found that gas phase chemistry at temperatures up to 1000 K can be modelled without the need to resolve the boundary layer of the small droplets.

Characteristics of Gas Mixture Supply/Pressure Control Using Non-Evaporable Getters in a Discharge-Type Fusion Neutron Source

The first tritium burning experiments of the discharge type fusion neutron source were conducted in January 2015, using a 93% deuterium and 7% tritium gas mixture. In order to conduct the experiment in a closed environment, a gas feed and exhaust system using non-evaporable getter material was prepared. This system was designed to minimize tritium usage and produce measurable changes in the neutron production rate on the basis of the dependence of the equilibrium pressure on getter temperature as included in the manufacturer’s data sheet. However, the present experiments revealed that the gas supply was insufficient and that the discharge duration was limited to about 2 minutes by the pressure drop during discharge.To determine the cause, verification experiments using hydrogen and deuterium gas were performed. It was found that the pressure variation with getter temperature could be mimicked by exploiting isotope effects and adjusting the hydrogen/deuterium concentration in the getter material according to the gas released into the vacuum chamber. Moreover, prolonged maintenance of a discharge was demonstrated by roughly tripling the amount of gas.The tritium concentration in the gas mixture, estimated on the basis of the present results, varied between 1.5% and 6.7% according to the assumptions used.

Impedancemetric NOx Sensors Based on LSM and LSM-Au Sensing Electrodes

An ideal NOx sensing electrode for diesel exhaust gas systems should possess high sensitivity and selectivity to NOx (i.e., NO and NO2) and low cross-sensitivity to interfering exhaust gases. In addition, it should be possible to fabricate the electrode readily at low cost. Gold (Au) has been rigorously studied as a sensing electrode for Y2O3-doped ZrO2 – YSZ electrolyte based sensors and found to demonstrate high NOx sensitivity and low water cross-sensitivity. However, the low melting temperature of Au and thermal expansion mismatch with YSZ limits the feasibility of Au as a sensing electrode. The perovskite, strontium-doped lanthanum manganite, La0.8Sr0.2MnO3 – LSM is an attractive alternative to Au from a manufacturing perspective as tolerates the high firing processing steps for accompanying sensor components and its thermal expansion coefficient is more compatible with YSZ. In addition, LSM has demonstrated low cross-sensitivity to interfering gases, such as NH3. Yet managing water cross-sensitivity remains challenging for LSM based sensors. In this work a detailed study was carried out on LSM and LSM-Au composite sensing electrodes in order to explore the combined benefits of LSM and Au. The NOx response of LSM and LSM-Au supported sensors was evaluated with respect to sensitivity, selectivity, accuracy, and response rate using the impedancemetric method. In addition, the frequency dependence of the sensors was studied to better understand the role of the operating frequency on the electrochemical behavior of the sensors. LSM and LSM-Au composite sensing electrodes were fabricated using standard ceramic processing methods. Electrode supports containing LSM-Au were made using powder mixtures of 90 wt% LSM (Inframat Advanced Materials) and 10 wt% Au (Alfa Aesar) that was uniaxially pressed at 200 MPa and fired at 1400 °C for 5 hours to achieve a density of ~ 95%. The electrolyte was 8 mol% YSZ (Tosoh Corp.) that was made into a slurry. A portion of the LSM-Au pellet was dip coated with the YSZ slurry. Several LSM-Au pellets with YSZ coating were co-fired at 1000 °C for 1 hour. The counter electrode was coated onto the porous YSZ electrolyte using a slurry made from LSM-Au powder, and the pellets were fired again at 1000 °C for 1 hour resulting in LSM-Audense/YSZ/LSM-Auporous cells to serve as NOx sensors. The sensors with pure LSM SE were made following the same procedure as LSM-Au based sensors. Frequency dependent impedance measurements were collected using a Gamry Reference 600 for sensors exposed to various gases at a flow rate of 500 sccm and operated at 575 °C under dry and humidified conditions. The oxygen concentration in the test gas environment was varied from 5 - 18%. The microstructural properties were analyzed based on scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Mercury Intrusion Porosimetry (MIP) and Archimedes method. The electrochemical behavior of the sensors in terms of frequency dependence, response time (τ90), exhaust gas cross-sensitivity, and oxygen partial pressure dependence was determined from impedance spectroscopy data. The impedance studies indicated the LSM-Au based NOx sensors demonstrated about 25% greater sensitivity to NOx for concentrations between 0–50 ppm, in comparison to LSM based sensors. As the gas concentration increased, NOx sensitivity for the LSM based sensors became more similar to the response for LSM-Au based sensors. Sensor sensitivity was based on the angular phase component of the impedance that varies with frequency. It was found that NOx sensors with an LSM-Au sensing electrode were sensitive to NOx over a wider frequency range from 1 - 250 Hz, in comparison to LSM based sensors where the frequency range was 1 - 125 Hz for NOx sensitivity. Cross-sensitivity studies indicated that sensors composed of LSM and LSM-Au electrodes were mostly impacted by interference of H2O and O2. However, the addition of Au in LSM significantly reduced the impact of water cross-sensitivity. Data indicated water cross-sensitivity was approximately 58% lower for sensors with LSM-Au electrodes, in comparison to those with LSM electrodes. However, increasing O2 in the gas stream caused water sensitivity to become more similar for both electrodes. This indicated oxygen cross-sensitivity was slightly higher for sensors with LSM-Au electrodes versus LSM electrodes. Measurements for the response time (τ90) indicated LSM-Au based sensors were slower than those supported with LSM, possibly due to oxygen inference. Overall, sensors containing the LSM-Au composite electrode demonstrated improved NOx sensing capabilities, particularly at lower NOx concentrations, and lower water cross-sensitivity in comparison to those with an LSM electrode. Improving response time and reducing oxygen dependence may be possible by varying the amount of Au and LSM within the sensing electrode.

INSTALASI PERMESINAN PADA KAPAL PSP 01

Kapal PSP 01 merupakan kapal latih sekaligus kapal penangkap ikan yang dimiliki oleh Departemen Pemanfaatan Sumberdaya Perikanan (PSP), Fakultas Perikanan dan Ilmu Kelautan (FPIK), IPB. Kapal ini menggunakan tenaga penggerak inboard engine berjenis diesel empat langkah yang berasal dari truk Mitsubishi Canter dengan tipe 4D30-C. Penelitian ini bertujuan untuk mendeskripsikan modifikasi instalasi permesinan di Kapal PSP 01 dan mendeskripsikan kesesuaian instalasi permesinannya mengacu pada pedoman FAO tahun 2009 tentang Safety Guide for Small Fishing Boats. Pendekatan dilakukan dengan menggunakan metode studi kasus dimana dilakukan pengamatan dan pengumpulan data yang meliputi modifikasi pada instalasi permesinan Kapal PSP 01 serta kesesuaiannya terhadap pedoman FAO tentang safety guide for small fishing boats. Hasil penelitian didapat bahwa mesin kapal PSP 01 dimodifikasi pada bagian sistem penyalaan, sistem bahan bakar, sistem pelumasan, sistem transmisi, dan sistem pendingin mesin. Berdasarkan pedoman FAO tahun 2009 tentang Safety Guide for Small Fishing boats, instalasi permesinan Kapal PSP 01 dalam hal sistem pompa lambung terpenuhi 58,33%, sistem bahan bakar terpenuhi 52,63%, sistem pembuangan gas pembakaran terpenuhi 33.33%, ventilasi kamar mesin terpenuhi 0%, rangkaian instalasi kelistrikan terpenuhi 85,71%, instalasi baterai terpenuhi 100%, pemeriksaan harian sebelum menyalakan mesin terpenuhi 75%, pemeriksaan harian setelah menyalakan mesin terpenuhi 100%, pemeriksaan tiap empat belas hari terpenuhi sebesar 20%, dan pemeriksaan tiap 100-150 jam setelah mesin beroperasi terpenuhi sebesar 0%.

The Analysis of Exhaust Gas Characterization in Reducing CO and HC Gas Pollution on the EFI Engine of Daihatsu Luxio 1500 CC

Air pollution from highways, particularly in an urban area which density and mobility are already on the verge of solid boundaries, resulting in environmental and human health problems. This is due to the lack of standardization of testing exhaust gas by the governmental body. Accurate results from the test and technology standardization on exhaust system which is one important component for gas pollutant elimination from the vehicle. In the present work, we examined the role of some modified exhausts on the level of pollutant exhaust, i.e. CO, HC, NOx gas. Experimental design for controlled variable is the speed, torque of the wheel, and gear position. Several modifications of exhaust gas were tested were tested, i.e. Standard, 3-way catalytic converter, racing and 2-ways catalytic converter. The data is gained through dynamometer and exhaust gas Analyzer as a speedometer gauges, torque wheels, and levels of exhaust gas that comes out of the tailpipe. Statistical analysis of the results uses one-way ANOVA. The result showed that the order in reducing exhaust gas CO and HC are: (1) two-way exhaust gas and 3 Way Catalytic Converter exhaust gas, (2) standard and (3) modified exhausts. 3 Way catalytic converter was the best to eliminate NOx than other three exhaust gas system

Laboratory station for research of the innovative dry method of exhaust gas desulfurization for an engine powered with residual fuel

Development of technology for exhaust gas desulfurization in marine engines using the dry method is, nowadays, a priority due to the calendar of introducing restrictions by the Directive of the European Parliament and of the Council 2012/33/EU of 21 November 2012. According to this directive, starting from 1 January 2015, inside the SECA (Sulphur Emission Control Area) the maximum sulfur content of marine fuels used on territorial seas is 0.1% per weight unit. But at the same time the directive allows for the use of exhaust gas desulfurization plant operating in a closed system. The ship equipped with the system will be able to use fuels with a high sulfur content, which will then be removed from the exhaust gas through an applied adsorber, and the reacted adsorbent is received by specialized services stationed in harbors. The International Maritime Organization has set a limit value of the emissions of sulfur oxides in exhaust gases of marine engines at 6 g/kWh (International Convention for the Prevention of Sea Pollution from Ships MARPOL 73/78 Annex VI, Regulation 14). Contemporary methods of exhaust gas desulfurization in marine engines are all expensive methods (4-5 million euro). This is, among other reasons, due to the limited market audience, but primarily due to the monop-olized position of manufacturers offering fabrication and assembly of this type of marine ship installations. Proposed as part of a research project financed by the Regional Fund for Environmental Protection and Maritime Economy in Gdansk, the dry method (adsorption) reducing SOx emissions in exhaust gases of marine engines, is an alternative, and a definitely cheaper and therefore competitive solution, compared to the wet methods (absorption), which are currently the most widely used in marine scrubber installations. Importantly, as confirmed by the results of the study, the proposed dry method, in addition to the effective reduction of sulfur oxides, also reduces emissions of nitrogen oxides and carbon monoxide. The paper presents the configuration and measurement capabilities of the test station built under the project, as well as the representative results of the investigations so far. During the exhaust gas desulfurization test a sodium adsorbent (sodium bicarbonate) and its modifications were used in the process of mechanical, chemical, and thermal activation. Two physicochemical processes were studied during the development of the method: • of adsorbent’s reaction on the chemical emission of the exhaust gas – the effectiveness of SOx and NOx compound removal, with various structural solutions in the process reactor, • the impact of the adsorber on the emission source of sulfur oxides, that is, on the compression-ignition engine. Therefore, one of the priorities of the project, with a utilitarian significance, was to determine the impact of the inclusion of the desulfurization installation in the exhaust gas system on the energy ratios of the engine.

New gas exhaust system for use in the dry quenching of coke

A new design is proposed for the dry-quenching chamber in coke production. As shown by research on a cold physical model, the new gas distributor and gas-exhaust system ensure that the motion of the cooling gas resembles ideal displacement. The total volume of the dead zones and zones with reduced cooling rate is no more than 15% of the dry-quenching chamber.

Engineering Solutions for Cooling Aluminum Electrolyzer Exhaust Gases

During aluminum production by self-fi ring anode technology, complete combustion of anode gas components (carbon monoxide, resin substances) is accomplished in electrolyzer burner units. With the aim of reducing combustion product temperature entering the gas conduit network of the electrolyzer body, air is fed into a burner unit in excess (α = 6). This amount considerably exceeds that recommended for burning gaseous fuel. As a result of the excessive air intake, excess air the temperature in the combustion zone may be reduced to 300°C. Unburned resin substance is carried with this into the gas exhaust system that is cooled, condensed, and together with dust particles contained in transported anode gases, is deposited on the walls of gas conduits reducing their useful cross section. An improvement in anode gas fuel component complete combustion by optimizing excess air within the limits of α = 1.5–1.2 provides a temperature within the combustion zone within the limits of 1270–1330°C. However, in the process the temperature of combustion products entering from a burner into the gas circuit increases to 1000°C and above, and this is connected with the risk of irreversible deformation of steel gas conduits and melting of gas cleaning unit (GCU) bag filters whose permissible operating temperature is in the range 140–160°C. Engineering solutions are proposed in this article aimed at providing safe operation of gas conduit circuits and electrolysis housing GCU with increased efficiency for burning resin substances in electrolyzer burner units.

Exhaust gas condensate – formation, characterization and influence on platinum measuring electrodes in diesel vehicles

Particle emission from diesel vehicles are subject to strict emission limits due to their harmful effects on humans and the environment. For this, soot particles are trapped in a diesel particulate filtering system (DPF) as part of the exhaust gas treatment. To monitor the DPF filtering efficiency throughout its lifetime, one possibility is based on a particulate matter sensor (PM-sensor) mounted downstream the DPF, collecting soot on its interdigital platinum electrodes. Besides soot particles, the electrodes can also be exposed to exhaust gas condensate which may accumulate throughout repeated cold starts and low load conditions. During sensor operation the temperatures are above the boiling point of water, whereby the water is vaporized and inorganic residues can remain on the sensing element and consequently changes in signal and surface are conceivable. To investigate this a test procedure at an engine test bench was developed to observe condensate formation and its transport within the exhaust gas system. In additional laboratory tests the impact of two condensates from diesel vehicles onto platinum measuring electrodes was investigated. SEM‐EDX was used for the sensing element surface analysis. Exhaust gas condensates were analyzed via ICP‐OES as well as IC. In the most exhaust gas condensates particularly transition metals with concentrations <10mg/L were verified. At a surface temperature of 100°C and a voltage of 45.6V electrophoresis occurred and the results show metallic deposits of iron on the surface of the cathode. Conductive dendrites containing copper, sodium and sulfur occurred in the gaps, which lead to an increasing current. Furthermore, sodium deposits influence the electric field between cathode and anode due to the formation of new electric potentials in the gaps whereby more soot is needed for the same signal which results in a decrease of the sensitivity and an increase of the resistance.

A Parametric Study of Diesel Oxidation Catalyst Performance on CO Reduction in Diesel Dual Fuel Engine Exhaust

In this research study, a synthetic exhaust gas system is employed to simulate various exhaust conditions similar to those from conventional diesel and Dual Fuel-Premixed Charge Compression Ignition (DF-PCCI) combustion. OEM DOC is tested to compare the effectiveness of reducing CO from both exhaust characteristics. Variations of the temperature and the concentration of CO, THC, and O2 are done to investigate DOC performance on CO reductions according to Design of Experiment (DOE) concept. The results showed that in DF-PCCI exhaust conditions, DOC requires higher exhaust gas temperature as well as O2 concentration to reduce CO emissions.

Making shipping greener: comparative study between organic fluids and water for Rankine cycle waste heat recovery

The largest source of energy loss in ships is found in the propulsion system. This study focuses on the concept of managing waste heat energy from the exhaust gases of the main engine. Using waste heat recovery systems (WHRSs) to make shipping more efficient represents a good area of opportunity for achieving the shipping industry's green objectives. Organic Rankine cycles have been applied in land-based systems before, showing improvements in performance when compared with the traditional Rankine cycle. As marine environmental rules requiring greener vessels and engine thermal efficiency continue to increase, thus reducing the available energy in the exhaust, organic Rankine cycle WHRSs become a more attractive option.The proposed WHRS was modelled using MATLAB for a typical ship installation with a slow speed diesel engine and a WHRS installed after the steam boiler in the exhaust gas system. The energy recovered from the exhaust gas flow is transformed via the thermodynamic cycle – coupled with a generator – into electricity, which helps to cover the ship's demand. The MATLAB code found the highest electric power output, hence the maximum fuel and CO2 emission savings possible, by v varying the WHRS HP. Water and four organic fluids were considered and their performance was compared over a range of different engine operating conditions. A representative ship operating profile and a typical marine generator were used to measure CO2 emission reductions. The implications of having flammable organic fluids on board are also briefly discussed. This work demonstrates that a simple organic Rankine cycle can be more effective than a steam cycle for the same engine operating conditions.

Cooling of the Anode Gases of Aluminum Reduction Cells in Alumina-Heating Heat Exchangers

An analysis is made of the amount of heat lost in heating alumina to the temperature of the melt after it is charged into the reduction cell. Also analyzed are the amount of electric power consumed to make up for this loss and the amount of heat that the anode gases carry off into the gas exhaust system. A technical solution is proposed to reduce the amount of energy consumed by reduction cells with a self-baking anode. The solution entails using the heat of the anode gases to heat the alumina, which makes it possible to reduce unit electric-power consumption by 135–170 kWh/ton Al.

Comparison between a Plate and a Tube Bundle Geometry of a Simulated Thermoelectric Generator in the Exhaust Gas System of a Vehicle

Numerous research projects in automotive engineering focus on the industrialization of the thermoelectric generator. The development and the implementation of thermoelectric systems into the vehicle environment are commonly supported by virtual designing activities. In this paper a customized simulation architecture [1] for thermoelectric generators, developed in research project TEG2020, is used to compare two very different TEG concepts: a plate and a tube bundle geometry. The installation space serves as a restriction and therefore is the same for both systems.There are slight advantages in maximum power output, nominal back pressure and overall weight of the tube bundle geometry compared to the lightweight and cost-effective planar thermoelectric generator presented in [1] and [2]. The efficiency of both systems is nearly the same. However there are some disadvantages of the tube bundle geometry in required mass of thermoelectric material, efficiency based on the mass of thermoelectric material, complexity and necessary cooling load.

Influence of an Optimized Thermoelectric Generator on the Back Pressure of the Subsequent Exhaust Gas System of a Vehicle

Numerous research projects in automotive engineering focus on the industrialization of the thermoelectric generator (TEG). The development and the implementation of thermoelectric systems into the vehicle environment are commonly supported by virtual design activities. In this paper a customized simulation architecture is presented that includes almost all vehicle parts which are influenced by the TEG (overall system simulation) but is nevertheless capable of real-time use. Moreover, an optimized planar TEG with minimum nominal power output of about 580 W and pressure loss at nominal conditions of 10 mbar, synthesized using the overall system simulation, and the overall system simulation itself are used to answer a generally neglected question: What influence does the position of a TEG have on the back pressure of the subsequent exhaust gas system of the vehicle? It is found that the influence of the TEG on the muffler is low, but the catalytic converter is strongly influenced. It is shown that the TEG can reduce the back pressure of an exhaust gas system so much that its overall back pressure is less than the back pressure of a standard exhaust gas system.