Boiler Installations Research Articles

Эффективность комбинированных теплоутилизационных системкотельных установок (часть 1)

Эффективность комбинированных теплоутилизационных системкотельных установок (часть 1)

Distinctive features of high-ash bituminuos coals combution with low milling fineness in furnace chambers with bottom blowing

Nowadays the problem of improvement of pulverized coal combustion schemes is an actual one for national power engineering, especially for combustion of coals with low milling fineness with significant portion of moisture or mineral impurities. In this case a big portion of inert material in the fuel may cause impairment of its ignition and combustion. In addition there are a lot of boiler installations on which nitrogen oxides emission exceeds standard values significantly. Decreasing of milling fineness is not without interest as a way of lowering an electric energy consumption for pulverization, which can reach 30% of power plant’s auxiliary consumption of electricity. Development of a combustion scheme meeting the requirements both for effective coal burning and environmental measures (related to NOx emission) is a complex task and demands compromising between these two factors, because implementation of NOx control by combustion very often leads to rising of carbon-in-ash loss. However widespread occurrence of such modern research technique as computer modeling allows to conduct big amount of variants calculations of combustion schemes with low cost and find an optimum. This paper presents results of numerical research of combined schemes of coal combustion with high portion of inert material based on straight-flow burners and nozzles. Several distinctive features of furnace aerodynamics, heat transfer and combustion has been found. The combined scheme of high-ash bituminouos coals combustion with low milling fineness, which allows effective combustion of pointed type of fuels with nitrogen oxides emission reduction has been proposed.

Characteristics of the ignition of organic coal–water fuels for boiler installations

The ignition processes of organic coal–water fuels (OCWFs) in the flow of a heated oxidant (temperature, 700–1000 K; velocity, 0.5–5 m/s) were studied. The experiments were carried out with the small single drops of OCWFs (radii, 0.2–0.5 mm), which correspond to the injection devices of typical boiler installations. The component base of the test composition fuels included B2 brown coal, typical waste coals (the filter cakes of G and D coals), spent motor and transformer oils, and petroleum residue. The influence of the component composition (the properties and concentrations of solid and liquid combustible components) on the characteristics of the initiation of the combustion of single OCWF drops was found. The dependences of the delay times of ignition and complete combustion on the temperature of an oxidant and on the drop sizes of OCWFs were determined. It was established that, at maximum oxidant temperatures (above 900 K) and minimum drop sizes (smaller than 300 μm), difference between the integral characteristics of ignition was sufficiently small (smaller than 10%) for the fuels prepared from components with substantially different properties.

Методика расчета рН и концентраций ионных примесей питательной воды на ТЭС по измерениям удельной электропроводности

Background: Tightening standards for the quality of thermal power plants water coolants and development of automatic chemical monitoring systems for water-chemical regime make it necessary to extend the diagnostic capacity of thermal power plant monitoring systems. Use of the most accurate measurement of coolant quality parameters, such as specific electrical conductivity and pH, increases boiler systems reliability and enables water regime diagnostics. This direction is adopted in power engineering in Western countries. In particular, the Swan firm (Switzerland) has developed and introduced to the Russian energy market its automatic analyzers «FAM Deltacon pH» and «AMI Deltacon Power». The purpose of our research is to develop techniques of indirect measurements and devices of automatic chemical control which are technologically not inferior to the best world samples. Materials and methods: The developed techniques are the result of in-depth studies conducted in the field of the electrolyte solutions theory, the theory and practice of ionic balance in water solutions by using the innovative stands of the Department of Chemistry and Chemical Technologies in Power Engineering. Similar techniques and stands were for the first time designed at ISPEU and have no analogs in other higher education institutions of Russia. Results: The study deals with three variants of calculating indirect determination of pH and ammonia concentration based on specific conductivity measurements of refrigerated samples. The calculation techniques are based on specific solutions to the generalized mathematical model of ionic equilibria in conditions of good-quality feed water in boiler installations. The paper represents the results of laboratory research into and industrial testing of the new techniques of indirect determination of water quality standard values at heat power stations. An algorithm has been selected to calculate parameters of industrial systems of automatic chemical control.  «Вестник ИГЭУ» Вып. 5 2016 г. ФГБОУВО «Ивановский государственный энергетический университет имени В.И. Ленина» 11 Conclusions: The suggested techniques and algorithms have been tested in industrial environments at heat power plants and partly implemented in developing new devices and automatic chemical control systems. The scientific value of the results obtained consists in receiving and justification of the calculation techniques suitable for practical use at heat power plants.

Method and algorithm of ranking boiler plants at block electric power stations by the criterion of operation reliability and profitability

A method and an algorithm of ranking of boiler installations based on their technical and economic indicators are proposed. One of the basic conditions for ranking is the independence of technical and economic indicators. The assessment of their interrelation was carried out with respect to the correlation rate. The analysis of calculation data has shown that the interrelation stability with respect to the value and sign persists only for those indicators that have an evident relationship between each other. One of the calculation steps is the normalization of quantitative estimates of technical and economic indicators, which makes it possible to eliminate differences in dimensions and indicator units. The analysis of the known methods of normalization has allowed one to recommend the relative deviation from the average value as a normalized value and to use the arithmetic mean of the normalized values of independent indicators of each boiler installation as an integrated index of performance reliability and profitability. The fundamental differences from the existing approach to assess the “weak components” of a boiler installation and the quality of monitoring of its operating regimes are that the given approach takes into account the reliability and profitability of the operation of all other analogous boiler installations of an electric power station; it also implements competing elements with respect to the quality of control among the operating personnel of separate boiler installations and is aimed at encouraging an increased quality of maintenance and repairs.

Possible ways of reducing the effect of thermal power facilities on the environment

The main trends in the integrated solution of thermal power engineering environmental problems are pointed out taking the Mosenergo power company as an example, and the data are given with respect to the structure of the power engineering equipment of the city of Moscow and its change, energy consumption, and generation of heat and electric energy. The dynamics of atmospheric air pollution of Moscow from 1990 to 2010, as well as the main measures on reducing the adverse effect of the power engineering equipment operation, is given. The results of original designs by the Department of Boiler Installations and Power Engineering Ecology (KU&EE) are given concerning the reduction of nitrogen oxides emissions and the decrease of the noise impact produced by the power engineering equipment.

Analysis of Problems Occured During Welding of New Genreation Bainitic Steel 7CrMoVTiB10-10 (T24)

Abstract A dynamic development of steels for components for usc boilers used in fossil fired power plants creates new welding problems. Introduction of new combinations of alloying agents, which are used to improve mechanical properties, especially creep resistance, does not remain indifferent as to the weldability of the newest steels. Every new steel grade which will be used for pressure components in power plants boilers has to be precisely tested. The most important processes that require profound research are bending and welding. It is crucial to examine all new steel grades and use the knowledge to elaborate technologies which could be used during prefabrication and assembly of boiler installations. As an example 7CrMoVTiB10-10 also known as T/P24 is given.

Biomass boiler conversion potential in the eastern United States

The U.S. is the world's leading consumer of primary energy. A large fraction of this energy is used in boiler installations to generate steam and hot water for heating applications. It is estimated there are total 163,000 industrial and commercial boilers in use in the United States of all sizes.This paper characterizes the commercial and industrial boilers in the 37 states of the Midwest, Northeast, and Southern regions of the U.S. in term of number of units, unit capacity, aggregate capacity, and fuel type. A methodology is developed for evaluating and ranking the potential for converting from existing fossil-fuel boilers to biomass boilers in these states.In total, 3495 oil and coal boiler units in industrial and commercial buildings, and 1067 major wood energy facilities in the 37 eastern states were identified. These represent a subset of existing and potential conversions from fossil fuels to woody biomass. Based on this sample and energy consumption data from the Energy Information Administration (EIA), we estimate that there are currently 31,776 oil, coal, and propane boiler units over 0.5 MMBtus/hour capacity in these 37 states, representing a total energy consumption of 1.7 quadrillion Btus, or roughly the equivalent of 287 million barrels of oil. Were these units all converted to woody biomass fuel, they would consume a total of 121 million dry tons of wood per year, about three times the most recent US DOE estimates of woody biomass availability in those regions. Since only the most economical conversions typically occur, the reality of woody biomass market availability combined with thermal fossil-fuel consumption patterns suggests that roughly one-third of all potential projects could be achieved under sustainable utilization of existing biomass feedstocks in the three regions.Analysis of the results indicates that a targeted response to wood-conversion initiatives will yield the most successful program of fossil-fuel replacement in thermal applications. A ranking index developed in this study through analysis of existing boiler installations and availability of wood feedstocks suggests that the top ten states in the eastern United States on which to focus future messaging, feasibility studies, and policy development for potential woody biomass conversions are:1. Maine, 2. Texas, 3. New York, 4. Florida, 5. Georgia, 6. Alabama, 7. South Carolina, 8. North Carolina, 9. Arkansas, 10. Pennsylvania.

Experimental investigation on gaseous emissions from the combustion of date palm residues in laboratory scale furnace

Emissions characteristics from the combustion of five date palm residues, DPR, (Date Palm Leaflets, Date Palm Rachis, Date Palm Trunk, Date Stones and fruitstalk prunings) in a laboratory scale furnace were investigated. Release of gaseous products such as CO2, CO, VOC, NOx and SO2 were measured at 600–800°C. The main goal was to analyze thermal behaviors and gaseous emissions in order to select the most convenient biofuel for an application in domestic boiler installations. Regards to biofuel characteristics, date stone have the highest energy density (11.4GJ/m3) and the lowest ash content (close to 1.2%). Combustion tests show that among the tested date palm residues, date stone may be the promising biofuel for the design of combustion processing system. However, a special attention to the design of the secondary air supply should be given to prevent high emissions of CO and volatile matters.

A Tale of Two Biomass Boilers

ABSTRACT What could be better than using energy grown locally to heat your facility? This article discusses two biomass boiler installations at two typical public school facilities in Pennsylvania. These systems were installed at the Benton Area School District in 2009 and at the East Lycoming School District in 2010. This article provides an overview of biomass energy and biomass boiler technology. Important aspects of the design, costs, and savings of these two projects are analyzed. Discussion of design includes heating multiple buildings versus a single building. Typical biomass boiler system design elements such as fuel storage requirements, fuel handling, boiler sizing, and backup heating equipment are investigated. Costs of both projects are evaluated, and clarification of key cost areas are highlighted. An explanation of the biomass boiler system savings is presented, along with information regarding project funding and air quality permitting. Unique to these two schools is that one school is usin...

To Protect and Serve

To Protect and Serve

Schematic and parametric optimization of solar+fuel boiler installations

A double-loop solar+fuel boiler installation scheme is considered. The scheme increases the hot water load replacement factor thanks to the heat produced by the solar technical part with increase of the thermal efficiency of the solar attachment.

The development of a dynamic model to simulate boiler controls

There has long been the need to improve the guidance for the control of multiple boiler installations. The literature shows that there is no generic guidance on how boiler plant — as opposed to the heating system — should be best controlled, despite their widespread use and many years of experience with these systems. This paper presents a simulation model that enables detailed investigation of multiple boiler operation under different control regimes. Five different conditions are presented in this paper. The first three show that individual boiler firing patterns behave as would be expected under ideal conditions. The loads for these simulations were chosen specifically to test this, and to provide some verification of the model. Two further tests were conducted to show firing patterns that may occur under typical control regimes. The resulting firing patterns showed unnecessary cycling of both boilers, a cause of premature failure and reduced efficiency. Practical applications: This paper presents the first stages of an investigation into the setting up and operation of multiple boiler control systems. A review of academic and industrial literature shows there to be very little guidance on how such control systems should be configured, and how different configurations will affect the system performance. This work is developing validated boiler models that can be used to investigate how sensor positioning and switching differentials can affect firing rates and interactions between boiler modules. In this way control settings can be more appropriately specified and commissioned. Excessive boiler cycling can lead to early failure of boilers and increased energy use. The results presented in this paper show that interaction between boilers due to poor sequence control settings will lead to additional and unnecessary cycling of boilers under part load conditions. The guidance arising from this work will help to extend boiler life and reduce fuel waste.

Drainage and economic utilization of methane from coal seams in the Jastrzebie mining-field

The paper presents the resources and present status of coal-seam methane from the mining field of JSW S.A., as well as trends in its application both in JSW S.A. plants and elsewhere. For the period 1999–2001, the dynamics of growth of methane utilization are shown. Perspectives of methane drainage are considered, with regard to both work and the realization of restructuring programs in the mining industry. Demand and supply of methane are discussed, taking into account real and potential opportunities. An assessment was made of the emissions to the atmosphere both of methane and of other pollutants. An evaluation of the influence exerted by these measures on the performance of cogeneration of heat and electricity has been prepared. Several projects in progress are described, namely the increase of gas-firing in existing boiler installations, investment projects referring to the installation of gas engines for cogeneration of heat and electricity, utilization of the distribution network for the maximum utilization of gas and the designs of power-generation systems (using methane) for air conditioning in the mines.

Wood cofiring evaluation at TVA power plants

Foster Wheeler Environmental and Reaction Engineering International (REI) conducted site-specific case studies of cofiring wood-derived fuel and coal at existing fossil-fired boilers within the Tennessee Valley Authority (TVA) power generation system. The case studies were part of a one-year strategic biomass assessment of the TVA region, jointly funded by TVA Research and Development, the National Renewable Energy Laboratory (NREL/DOE), and the Electric Power Research Institute (EPRI). This paper addresses TVA's interest in utilizing biomass as a power generation option and the progress of the cofiring case studies through 1993. The analyses demonstrate that wood cofiring is economically feasible at cyclone boiler installations and may be a low-cost CO 2 mitigation strategy for many pulverized coal boilers.

96/01031 Safe buildings for the year 2000

Foster Wheeler Environmental and Reaction Engineering International (REI) conducted site-specific case studies of cofiring wood-derived fuel and coal at existing fossil-fired boilers within the Tennessee Valley Authority (TVA) power generation system. The case studies were part of a one-year strategic biomass assessment of the TVA region, jointly funded by TVA Research and Development, the National Renewable Energy Laboratory (NREL/DOE), and the Electric Power Research Institute (EPRI). This paper addresses TVA's interest in utilizing biomass as a power generation option and the progress of the cofiring case studies through 1993. The analyses demonstrate that wood cofiring is economically feasible at cyclone boiler installations and may be a low-cost CO2 mitigation strategy for many pulverized coal boilers.

Toxics control by activated charcoal within the “System Düsseldorf” full scale experience

Stadtwerke Düsseldorf AG is the utility company responsible for the energy supply of the City of Düsseldorf. To ensure the supply of power and district heat, it operates power plants with a total capacity of around 1100 MW, 600 MW of which are generated by coal-fired power plants with 13 boiler installations located at three different sites. In addition, it operates the refuse incineration plant of the city of Düsseldorf with a capacity of 450,000 tons per year of municipal refuse and industrial waste. Within the last few years, all of the above plants had to be retrofitted with flue gas cleaning systems for the removal of SO 2, HCl, HF, NO x , chlorinated hydrocarbons, vaporous heavy metals, etc. The three-stage semi-dry flue cleaning process “System Düsseldorf” meets these requirements, in addition to the following: simple and space-saving technology; flexible capacity; no waste water, no sewage problems; attractive investment and operating cost; utilization of residual products; adaptability to other flue gas cleaning technologies. As anticipated the dust, SO 2, HCl, HF, etc., emissions after the lignite-activated coke filter as the second stage, reach zero or near-zero. However, using the same material as a low temperature catalyst in the downstream third stage, the denitrogenisation resulted in emissions of not lower than 200 mg NO x per m 3. Consequently, to achieve lower NO x emissions, without reheating the flue gases, other materials were found, such as endowed synthetic carbon, zeolite, or a type of titanium dioxide, all of which are currently in long-term tests. To date, plants for more than 3 million m 3 flue gas per hour have been successfully built, and been proven in operation now for more than three years. The only residue from this type of cleaning system, a kind of gypsum, is reused for fabricating lime sand bricks and filling coal and ironpits.

Practical modelling of micro combined heat and power applications for local authority district heating schemes

The primary purposes of this paper are to describe a practical model which can be used to assist economic evaluation of district heating proposals, with particular reference to potential micro combined heat and power (CHP) applications, and to discuss the results of applying this model to a proposal for a particular scheme. The problems of realistic simulation of demand patterns, and the sensitivity of micro-CHP project values to scale, fuel prices, differential purchase/selling tariffs for electricity, duty cycle and plant utilization factors are discussed. Of several options, two were shown to be economically viable, relative to existing methods of supply (gas-fired boilers); however, the margin of benefit is small relative to wisely chosen modern boiler installations. A brief discussion of alternative methods of finance is provided; ceteris paribus, the proposed scheme would not be likely to attract venture capital from would-be lease-hire agencies. There is scope however for pilot schemes, whose results could be used to define more closely the limits of uncertainty of, for example, annual availability and duty cycle influences on the cost economics of operations.

The economical use of energy resources

The increasing cost of producing organic fuels, especially oil and gas, requires that great attention to be paid to increasing the efficiency of using energy resources and thus to reducing their consumption. The U.S.S.R. Long-Term Energy Management Program addresses the main ways to save energy. These include replacing more expensive fuels by cheaper ones, developing nuclear power and other measures aimed at improving the structure of the heat and energy balance, and increasing the efficiency of fuel and energy use. An especially large potential for savings is to be found in the production and utilization of low-temperature heat. In particular, new approaches are suggested to optimize the parameters of cogeneration plants and heat supply systems, as well as the parameters describing end uses by consumers. Emphasis is given to the promise of district heating with hot-water heaters run on natural gas, combined with gas-fired turbines, with recovery of exhaust heat. Heat pump installations provide space heat and hot water to dispersed consumer and boiler installations with fluidized-bed furnaces are of great importance, as are new schemes of heat supply for agricultural production and for biological conversion of organic waste. On the demand side, ways of lowering the requirements for low-temperature heat include enhancing the thermal resistance and tightness of buildings, updating building heat loss standards, incorporating new construction materials, and improving the methods for regulating the heat supply in district heating systems. The size of the potential savings of energy resources associated with each technology is estimated.

Major parametric effects on isothermality in horizontal steam-generating tubes at low- and moderate-steam qualities

In some special boiler installations (for example, once-through boilers and fluidized-bed type boilers), horizontal or slightly inclined steam-generating tubes are used for technological or other reasons. One of the problems of these installations, leading to frequent failures, appears to be the circumferential anisothermality that occurs at certain operating and geometric conditions in the horizontal boiler tubes. This is a serious constraint for successful boiler design and maintenance. Although we have studied the subject both experimentally and theoretically in previous works, major parametric effects on the tube top-to-bottom isothermality resulting from distinct two-phase flow phenomena are identified in this paper. The anisothermality creates high temporal and spatial variations in thermal stresses, which is of utmost importance to engineers involved in the design of industrial applications containing horizontal tubes. Approximate relationships, design recommendations, and a practical example of the proposed approach are presented.