Exhaust Boiler Research Articles

The preliminary full-scale experiment on the vessel's compact exhaust boiler’s prototype

The article is devoted to a preliminary full-scale experiment on a heat recovery stand, which is the initial stage of a full-scale study of the vessel's compact exhaust boiler of a new design. The experiment is carried out in order to test the mounted thermometry system and obtain the first data about the temperature distribution in the channels of an experimental exhaust boiler. The analysis of the results confirms the adequacy of the readings of the thermometry system, allows to talk about its correct operation, but, at the same time, it points to a number of illogical indications that require explanation.

Analysis of Efficiency of Thermopressor Application for Internal Combustion Engine

Contact cooling using thermopressor technologies is a promising direction for the development of energy-efficient technologies. This technology is based on the implementation of the thermo-gas-dynamic compression effect in special contact heat exchangers that consists of increasing the pressure while decreasing the temperature during the evaporation of a finely dispersed liquid injected into a gas flow moving at a speed close to sound. Upon application of the thermopressor for charge air cooling of the engine, the following result was obtained: an increase in the air pressure after the turbocharger by 340 to 480 kPa. The thermopressor can be used as a boost stage after the turbocharger, resulting in the reduction of a basic turbocharger compression work and the increase of engine power output accordingly. Reducing the work allows for the same air flow rate on the internal combustion engine to reduce the compressor power by 10 to 12%. This increases the temperature of the exhaust gases at the inlet of the exhaust boiler by 10 to 15 °C and boiler steam capacity, resulting in an increase in the power output of the utilization turbine generator with a corresponding reduction in the fuel consumption of the diesel generator of the ship power plant by 2 to 3%.

Investigation of the adverse effects of slow steaming operations for ships

The typical negative effects of prolonged slow steaming operations are investigated in this study. The scope of the research is to examine the effects of the carbon deposit formation on piston rings (lack of sealing function), exhaust boiler (reduction in the heat recovery capacity), turbocharger (lack of scavenging capacity), and injector, due to the prolonged slow steaming operation. It is necessary to identify the holistic adverse effects of the low-load operation on the main engine performance and subsequent components. The study shows that the negative consequences of a long-term slow steaming operation cause noteworthy efficiency degradation in marine diesel engines. The paper aims to clarify the barriers to the efficient operation of marine diesel engines via raising awareness of proper and planned maintenance for sustainable slow steaming. The degradation rates affect the total operational efficiency, CO2emissions, and fuel consumption. The study results show that the fuel consumption increases by 1.9%, 2.1%, and 1.9% of daily consumption and the corresponding CO2emission increments are 4.36, 4.29, and 3.48 kg CO2per nautical mile sailing of the container ship at specified speeds at 65%, 55%, and 45% engine loads, respectively. The efficiency variation leads significant amount of emission increment, while up to 50% decrement will enter into force by April 2022 for container ships. The study gives valuable insight into the increase in CO2emissions and fuel after long-term slow steaming for the near future with the stricter emission limits. The results provide considerable information about the deterioration effect on the whole energy system and help to estimate potential efficiency levels for marine diesel engines.

Design and Analysis of Ship Exhaust Boiler Flue Cleaning System Based on Computer

In recent years, the country for ship emissions of exhaust gas control is relatively loose, but also relatively lack of specific and effective supervision and scientific exhaust emissions and treatment technology, so China’s air pollution is increasingly serious. With the implementation of regulations on the emission of air pollutants from land-based sources such as motor vehicles and power stations, researchers have found that exhaust pollution from ships accounts for an increasing proportion of the overall air pollution, especially in port cities and coastal areas, causing great damage. In order to effectively reduce ship exhaust pollution in China, the Ministry of Transport through the establishment of ship emission control area program, stage by stage and regional limits on the sulfur content of fuel used by ships sailing in China’s ports and coastal inland river waters. Through the implementation of the regulations of the ship discharge control area, all kinds of pollutants discharged by ships have been significantly reduced, and the environment of the port area has been improved to a certain extent. At the same time, it is also necessary to use the computer and other high-tech constantly develop new ship exhaust cleaning mode to deal with the increasingly serious environmental pollution problem.

Analisa Prestasi Pembangkit Listrik Tenaga Uap (PLTU) Berbahan Bakar BatuBara Hasil Upgrading

Coal is a cheap fuel, so it is widely used by steam power plants (PLTU). With many PLTUs using coal, the demand for coal increases and the quality of the coal is decreasing and the price continues to rise. With this problem, it is necessary to improve coal quality, one of which is by upgrading using a gas exhaust boiler. With using rotary dryer, the coal will be upgraded from low calorie to high calorie by reducing the moisture content, which will then be applied to the tempo cycle software 5.1. After application at cycle tempo 5.1, the best efficiency increase for PLTU can be increased efficiency and decrease coal rate, which is best obtained in the third experiment which achieved 37,041% efficiency with a coal rate of 17,567 kg / s.

EXHAUST GAS RECOVERY FROM MARINE DIESEL ENGINE IN ORDER TO REDUCE THE TOXIC EMISSION AND SAVE ENERGY: A MINI REVIEW

Nowadays, the use of exhaust gas energy seems to be a very promising key to increase the energy efficiency in maritime field by converting the thermal losses of ship into useful energy sources such as exhaust boiler, exhaust turbo charging or mini electrical generator, which ensure the best utilization of the fuel, reduce emission met IMO requirements and reduce the operating costs. Diesel engine exhaust gas energy, certainly the most interesting among the waste heat sources of a ship because of the heat flow and temperature, is always considered to utilize due to the exhaust gas energy is approximately 25-30% of total energy of burned fuels in internal combustion engines. By installing the main propulsion plant with a waste heat recovery system (WHRS), the fuel can be utilized more economically, because energy lost in the exhaust gas flow is less. Moreover, the amount of CO2 emissions related to the mechanical power output of engines may be dropped off. The paper presents the review of utilization of exhaust gas heat in ship and suggests a heating up method for biodiesel or bio-oils which fuel in diesel engine in order to get dual benefit.

Natural gas intracyclic attachment for energy generating unit based on gas turbine plant

In this article, problems of effectiveness increasing in complex power supply are considered. Disadvantages of centralized power engineering and advantages of power engineering capabilities organization in immediate consumer proximity are presented. Consumer needs satisfaction in electricity, heat supply and cold supply are offered to be realized by conversion of district and quarter boiler houses to trigeneration stations, which are based on gas turbine plants units. In this research, solutions of problem related to lack of fuel gas pressure for gas turbine engine power, which is included in gas turbine plant of trigeneration stations, are suggested. As a result, after considering possible variants of fuel gas pressure increasing, it was decided that there is a perspective of using fuel gas intracyclic compression attachment. Its operating principle involves organization of main steam extraction in heat cycle for booster compressor drive, which compresses fuel gas before its transfer to combustor of gas turbine plant. Results of gas compressor and drive steam turbine design are presented. These parts are included in fuel gas intracyclic compression attachment in specific unit of gas turbine plant. Also, general recommendations about new compressor and turbine stages design for any other units of gas turbine plant are pointed. Further, in the article, two variants of thermal circuit, based on gas turbine plant, are suggested. The first one is a circuit with hot water boiler, where exhaust gas recuperation after turbine is carried out for producing steam, related to fuel gas intracyclic compression attachment demands, and heat system water heating for consumer heat supply system. The second variant involves development of typical gas turbine plant unit in power station with exhaust boiler. There fuel gas intracyclic compression attachment is activated by steam work after exhaust boiler. Then, variants of diagram are compared between each other. Also advantages and disadvantages each of them are considered.

КОНСТРУКЦИЯ И РАСЧЕТ ТЕРМОЭЛЕКТРИЧЕСКОГО ГЕНЕРАТОРА ДЛЯ СУДОВЫХ ЭНЕРГЕТИЧЕСКИХ УСТАНОВОК

The article presents the design of a thermoelectric generator (TEG) for utilizing heat energy of exhaust gases of ship diesel engines. There have been chosen a TEG basic design and a technique for its efficiency raising. Geometric, heat and electric parameters of TEG have been calculated using RSD 49 ship project. Calculation of heat and electric parameters of TEG with intensive heat exchange on the surface of a hot node was made using sloping plates. The relation between TEG position (before and after exhaust boiler) and a Wartsila 6L20 main engine exhaust system has been determined. According to the analysis result, in case of TEG position after exhaust boiler and 100% load of main engine, estimates increased compared to a basic design: performance - 4%, capacity - 5%; output gas temperature decreased to 1%. At combined operation of TEGs positioned in the exhaust system of one main engine with exhaust boiler shut down and TEG positioned after exhaust boiler, estimates grew: capacity - 35%, performance - 14%; output gas temperature decreased to 19%. Total maximum capacity of TEGs positioned in the main engine exhaust systems makes 42.78 kW which is 1.78% of a ship power plant capacity.

СРАВНИТЕЛЬНЫЙ АНАЛИЗ ВЛИЯНИЯ СКОРОСТИ ГАЗА НА ТЕМПЕРАТУРНОЕ ПОЛЕ И ГИДРОДИНАМИЧЕСКИЕ ПОТЕРИ В ТЕПЛООБМЕННОЙ СЕКЦИИ КОМПАКТНОГО КОТЛА-УТИЛИЗАТОРА

The analysis of the numerical modeling results of gas dynamics in the ducts of the compact exhaust boiler is continued. Currently, there have been done three calculations for the same geometrical model; these calculations have different input speed values, as well as different methods of setting speed. It’s confirmed that in case of continuation of the original calculation with changed boundary condition (speed) in the inlet cross section the results coincide with results of calculation where originally set speed was the same. Thus, it becomes possible to perform several variants of calculations with the same geometry, but with different speed in one session (with minimum correction of initial data). So, the time of setting new temperature mode and the value of gas-dynamic resistance is reduced. Therefore, the time for preparing and carrying out the numerical experiment can be reduced. The influence of input speed on temperature field and hydrodynamic losses in exhaust boiler have been analyzed.

РАСЧЕТНОЕ ИССЛЕДОВАНИЕ ВОЗМОЖНОСТИ УЛУЧШЕНИЯ ТЕРМИЧЕСКОГО СОСТОЯНИЯ ЭЛЕМЕНТОВ ГАЗОТРУБНОГО КОТЛА-УТИЛИЗАТОРА

The numerical experiment is described, made in the student version of the finite element analysis ELCUT software based on a mathematical model of one of the most thermally loaded units (gas chamber - building) of the gas-tube exhaust boiler, the results of the experiment are set out. The objectives of the modeling are to determine the fields of temperature and temperature gradients of the shell of the gas chamber options with and without thermal insulation inserts, as well as quantitative and qualitative evaluation of the thermal state of the exhaust boiler’s neck for both cases. The preparation of numerical experiment is described: the creation of a geometric model of the test site in the form of a set of blocks with an individual set of properties for each of them; assignment of the 3-rd class boundary conditions in the media of contact surfaces; due to the structural complexity of the model and the limitations imposed by the student version of the software ELCUT, the step of finite element grid was set manually. The numerical modeling results proved advisability of reducing the temperature gradient in the metal of the gas chamber along its axis, reducing the overall temperature in the experimental element by installing heat-insulating insertion, as well as sufficiently confirmed exactly a high level of stresses in the shell of the gas chamber, which has no insulation. As a result, the most dangerous section of the exhaust boiler’s neck case was determined and the information on the state of the temperature of the neck case elements for options with and without thermal insulation insert was provided, indicating the possibility of double reduction of temperature gradients along the generator of the gas chamber and, accordingly, the possibility of double reduction of thermal stresses in the most loaded zone.

Lowering the effect of low‐frequency noise generated from boiler exhaust stacks.

Low‐frequency noise from exhaust boiler stacks at a semiconductor plant was measured and the low‐frequency noise spectrum was predicted using an analytical impedance model. Nearby residents complained that noise was rattling household items, such as windows and light fixtures. The semiconductor plant speculated that noise from two boiler exhaust stacks was the source of the problem. Sound pressure level measurements conducted at the plant revealed strong tones in the infrasound and low‐audible frequency range. The boiler exhaust stack noise source was theoretically characterized by deriving the mechanical impedance of the boiler exhaust stack and the radiation impedance of the top of the boiler exhaust stack as a simple unbaffled source. The analytical model predicted the resonant frequencies of the boiler exhaust stacks and these resonances closely matched the strong low‐frequency tones measured. Using this model, possible changes in controlling parameters of common exhaust boiler stack design are described that could decrease the overall noise radiating from the exhaust stacks. As one example, the plant appreciably decreased the sound power contribution from the upper exhaust stack resonances by lowering the overall output of the exhaust boilers. This change lowered the overall noise levels without the use of silencers.