An approach to the use of fixed carbon-volatile matter graph

The use of the fixed carbon-volatile matter (FC-VM) graph for quick calculations of proximate analysis data, as well as for simple presentation of coal classification is illustrated. From the position of the VM and FC values of a coal on the graph (on an ‘as received’ basis) it is possible to determine the approximate rank and class of the coal

Waste heat potentials in the drying section of the paper machine in Umka Cardboard Mill

This paper deals with methods for calculation of potentials of waste heat generated in paper/board production process. For that purpose, the material and heat balance of the cardboard machine at Umka Cardboard Mill has been determined. Field measurements were conducted in order to define the unknown values of process parameters used for calculation in the balance equations and modelling. The focus was given to the cardboard drying section, which consumes most of the energy supplied to the machine. Additional aim of the work presented in the paper was to evaluate the specific energy consumption and the thermal efficiency of all individual energy units within the machine's drying section. The results indicate two main sources of waste heat: waste heat released to the atmosphere with the discharge air from the present waste heat recovery system (14,380 kW), and waste heat released in the hall from the machine and extracted by the hall ventilation system (4,430 kW). Waste heat from both sources is characterized by fairly low temperatures 58-75°C and fairly high moisture content (30-40 g/kg). The specific heat consumption and specific steam consumption (consumption per tonne of produced cardboard) of the machine was 1,490 kWh/t and 1.4 t/t, respectively. The thermal efficiency of drying section and coating drying section was 55.6% and 33.6%, respectively. All these figures imply necessity for further waste heat utilization with the aim of improving the efficiency of energy use

Biomass gasification with chp production a review of the state-of-the-art technology and near future perspectives

This paper is a review of the state-of-the-art of biomass gasification and the future of using biomass in Serbia and it presents researches within the project "The Development of a CHP Plant with Biomass Gasification". The concept of downdrafi demonstration unit coupled with gas engine is adopted. Downdrafi fixed-bed gasification is generally favored for CHP, owing to the simple and reliable gasifiers and low content of tar and dust in produced gas. The composition and quantity of gas and the amount of air are defined by modeling biomass residues gasification process. The gas (290-400 m(3)/h for 0.5-0.7 MW biomass input) obtained by gasification at 800 degrees C with air at atmospheric pressure contains 14% H-2, 27% CO, 9% CO2, 2% CH4, and 48% N-2, and its net heating value is 4.8-6 MJ/Nm(3). The expected gasifier efficiency is up to 80%. The review of the work on biomass gasification has shown that the development of technology has reached the mature stage. There are CHP plants with biomass gasification operating as demonstration plants and several gasification demonstration units are successfully oriented to biofuel production. No attempt has been made here to address the economic feasibility of the system. Economics will be the part of a later work as firmer data are acquired

APPLICATION OF HEAT PUMPS FOR UTILIZATION OF WASTE HEAT IN INDUSTRY

U energetski intenzivnim industrijama kao što su livnice, čeličane, fabrike hemijske industrije, rafinerije i dr. značajne količine otpadne toplote se generišu u obliku rashladne vode čija temperatura je uobičajeno u opsegu od 25 do 40°C. U slučajevima kada se otpadni fluidni tokovi niske temperature ne mogu primeniti direktno u procesu, postoji mogućnost i tehnička rešenja da se oni iskoriste primenom toplotnih pumpi. U ovom slučaju otpadna toplota sa niskim toplotnim potencijalom (niskom eksergijom) iz raznih industrijskih procesa koristi se, posredstvom toplotne pumpe, kao toplotni izvor za zagrevanje vode za potrebe grejanja objekata, pripremu sanitarne tople vode, zagrevanje različitih procesnih voda i sl. U ovom radu prikazani su rezultati tehno-ekonomske analize koja je sprovedena za primer toplotne pumpe koja koristi otpadnu toplotu iz industrijskih procesa. U radu je razmotreno nekoliko različitih izvora otpadne toplote sa različitim karakteristikama u pogledu raspoloživog protoka fluida, temperature i vremenske raspoloživosti izvora otpadne toplote. Rezultati analize pokazali su da je primena toplotnih pumpi sa nominalnom toplotnom snagom od 295 i 2x390 kW, koje rade u režimu temperature 80/30°C i 80/35°C pri stepenu korisnosti od 3,2 i 3,3, u konkretnom slučaju opravdana, pri čemu je prost period povrata investicije u opsegu od 2,3 do 6 godina

Pollution distribution from new wet stack on TPP 'Kostolac B'

Studija o proceni uticaja na životnu sredinu postrojenja za odsumporavanje dimnih gasova TE 'Kostolac B' predstavlja sastavni deo investiciono-tehničke dokumentacije za nivo idejnog projekta. Izrada Studije ima za cilj da prikaže stanje životne sredine na tom području, da sagleda i analizira pozitivne i negativne uticaje na životnu sredinu do kojih će doći izradom ovog postrojenja. Studija takođe daje prikaz tehničkih i organizacionih mera predviđenih u cilju sprečavanja i smanjenja značajnih efekata rada pogona na životnu sredinu, posebno u odnosu na rešenja prikupljanja i odlaganja čvrstog i tečnog otpada, zaštite zemljišta i podzemnih voda, upravljanje otpadnim vodama, i dr. S ciljem utvrđivanja uticaja budućeg postrojenja za odsumporavanje dimnih gasova na kvalitet vazduha u užoj i široj okolini lokacije urađen je model zagađenja vazduha. Sprovedena analiza zasnovana je na ispitivanju uticaja različitih scenarija emisija štetnih materija iz blokova B1 i B2 TE 'Kostolac B' na kvalitet vazduha u centralnoj Srbiji. .Environmental Impact Assessment of FGD plant operation at TPP 'Kostolac B' is an integral part of technical documentation on Development of Investments, prepared for the Basic Design of the future FGD plant. The Study is developed with a goal to show the current state of the environment in the area of interest, to consider and analyze positive and negative environmental effects resulting from the future construction of FGD plant. The Study also proposes technical and organizational measures aimed at prevention and mitigation of environmental impact of the future plant operation, especially with respect to collection and disposal of solid and liquid waste, soil and groundwater protection, wastewater management etc. In order to determine effects of the future FGD plant on the air quality over the closer and broader area of the TPP 'Kostolac B' appropriate air pollution model has been developed. Analysis has been based on investigation of the effects of different pollutant emissions scenarios from both units of TPP 'Kostolac B' on the air quality in central Serbia.

Numerical simulations in design and optimization of elements of experimental installation of regenerative burners for tundish preheating in steel plant US Steel-Sartid Smederevo

Eksperimentalno postrojenje regenerativnih gorionika sastoji se od dva regenerativna zagrejača zasnovana na pebble-bed tehnologiji (PH) fluido-dinamičkog ventila (FDV), dva gorionika, ventilatora za otsisavanje dimnih gasova i ventilatora za snabdevanje postrojenja vazduhom za sagorevanje. Eksperimentalna instalacija će biti postavljena na stendu za zagrevanje međulonaca za livenje čelika u čeličani US Steel Serbia d.o.o. Namena ovog postrojenja je da se korišćenjem visokopredgrejanog vazduha za sagorevanje (K>1000°C) smanji potrošnja gasovitog goriva na polovinu sadašnje, koja iznosi 200 - 250 nrVh (na uslovima/7=101325 Pa, 7=273,15 K). Primenom programa za numeričke simulacije StarCD izvršeno je definisanje i optimizacija geometrije fluido-dinamičkog ventila i optimizacija položaja otvora za gorionike i otvora za otsisavanje dimnih gasova na poklopcu novog međulonaca za livenje čelika.Novi međulonac je 1,9 puta veće zapremine i njegov kapacitet iznosi 26,5 t čelika. Polazni parametri za numeričku simulaciju i optimizaciju geometrije fluido-dinamičkog ventila bila je razlika pritisaka ulaznih struja visoko-predgrejanog vazduha i dimnih gasova i potrebna vrednosti pritiska izlazne struje iz FDV visoko-predgrejanog vazduha. Trodimenzionalni model je definisan na osnovu realne geometrije ventila i sadrži 177744 ćelija (kontrolnih zapremina). Definisanje karakterističnih dimenzija FDV uz najmanji pad pritiska pri prolasku fluidnih struja i zadat procenat (odnos) mešanja struje vazduha i dimnih gasova predstavlja rezultat optimizacije geometrije FDV. Trodimenzionalni model novog međulonca i poklopca sastoji se od 300195 kontrolnih zapremina. Optimizacijom položaja otvora za gorionike i otsis produkata sagorevanja na poklopcu međulonca kapaciteta 26,5 t čelika dobijeno je ravnomerno polje temperatura na unutrašnjem ozidu međulonca u definisanom vremenskom intervalu nestacionarnog zagrevanja uz prepolovljenu potrošnju goriva od 100 m3/h, pri čemu je vreme i režim zagrevanja međulonca ostao nepromenjen.An experimental installation of regenerative burners consists of two regenerative Pebble-bed heaters (PH), one fluid - dynamical valve (FDV), two burners, one fan for flue gas exhaust and one fan for combustion air supply. Experimental installation will be situated at stand for tundish preheating in US Steel Serbia d.o.o. Steel factory. The purpose of this facility is to reduce natural gas as fuel consumption at half of current (200-250 nr7h at £-=101325 Pa, 7=273,15 K) by using high-preheated air for combustion. Design optimization of fluid-dynamical valve and optimization of position of burner heads and off-gas exit at tundish top cover by application of StarCD software for numerical simulation was performed. New tundish is 1,9 times higher capacity (26,5 t) than old one. Input parameters for numerical simulation and design optimization of fluid-dynamical valve are pressure difference between two inlet streams - high-preheated air and off-gas, and pressure value at outlet of high-preheated air. 3D model was made on basis of real valve geometry and consists of 177744 cells (control volumes). The result of numerical calculation and optimization procedure of FDV is optimal geometry definition, lowest pressure drop through the FDV and least value of two streams (high-preheated air and off-gas) mixing coefficient. 3D model of tundish and its top cover consists of 300195 control volumes. Optimization of position for burner heads and off- gas exhaust at tundish top cover brought uniform temperature field at inside of tundish refractory layer during transient process of preheating with minimal fuel consumption

Numerical simulations in design and optimization of elements of experimental installation of regenerative burners for tundish preheating in steel plant US Steel-Sartid Smederevo

Eksperimentalno postrojenje regenerativnih gorionika sastoji se od dva regenerativna zagrejača zasnovana na pebble-bed tehnologiji (PH) fluido-dinamičkog ventila (FDV), dva gorionika, ventilatora za otsisavanje dimnih gasova i ventilatora za snabdevanje postrojenja vazduhom za sagorevanje. Eksperimentalna instalacija će biti postavljena na stendu za zagrevanje međulonaca za livenje čelika u čeličani US Steel Serbia d.o.o. Namena ovog postrojenja je da se korišćenjem visokopredgrejanog vazduha za sagorevanje (K>1000°C) smanji potrošnja gasovitog goriva na polovinu sadašnje, koja iznosi 200 - 250 nrVh (na uslovima/7=101325 Pa, 7=273,15 K). Primenom programa za numeričke simulacije StarCD izvršeno je definisanje i optimizacija geometrije fluido-dinamičkog ventila i optimizacija položaja otvora za gorionike i otvora za otsisavanje dimnih gasova na poklopcu novog međulonaca za livenje čelika.Novi međulonac je 1,9 puta veće zapremine i njegov kapacitet iznosi 26,5 t čelika. Polazni parametri za numeričku simulaciju i optimizaciju geometrije fluido-dinamičkog ventila bila je razlika pritisaka ulaznih struja visoko-predgrejanog vazduha i dimnih gasova i potrebna vrednosti pritiska izlazne struje iz FDV visoko-predgrejanog vazduha. Trodimenzionalni model je definisan na osnovu realne geometrije ventila i sadrži 177744 ćelija (kontrolnih zapremina). Definisanje karakterističnih dimenzija FDV uz najmanji pad pritiska pri prolasku fluidnih struja i zadat procenat (odnos) mešanja struje vazduha i dimnih gasova predstavlja rezultat optimizacije geometrije FDV. Trodimenzionalni model novog međulonca i poklopca sastoji se od 300195 kontrolnih zapremina. Optimizacijom položaja otvora za gorionike i otsis produkata sagorevanja na poklopcu međulonca kapaciteta 26,5 t čelika dobijeno je ravnomerno polje temperatura na unutrašnjem ozidu međulonca u definisanom vremenskom intervalu nestacionarnog zagrevanja uz prepolovljenu potrošnju goriva od 100 m3/h, pri čemu je vreme i režim zagrevanja međulonca ostao nepromenjen.An experimental installation of regenerative burners consists of two regenerative Pebble-bed heaters (PH), one fluid - dynamical valve (FDV), two burners, one fan for flue gas exhaust and one fan for combustion air supply. Experimental installation will be situated at stand for tundish preheating in US Steel Serbia d.o.o. Steel factory. The purpose of this facility is to reduce natural gas as fuel consumption at half of current (200-250 nr7h at £-=101325 Pa, 7=273,15 K) by using high-preheated air for combustion. Design optimization of fluid-dynamical valve and optimization of position of burner heads and off-gas exit at tundish top cover by application of StarCD software for numerical simulation was performed. New tundish is 1,9 times higher capacity (26,5 t) than old one. Input parameters for numerical simulation and design optimization of fluid-dynamical valve are pressure difference between two inlet streams - high-preheated air and off-gas, and pressure value at outlet of high-preheated air. 3D model was made on basis of real valve geometry and consists of 177744 cells (control volumes). The result of numerical calculation and optimization procedure of FDV is optimal geometry definition, lowest pressure drop through the FDV and least value of two streams (high-preheated air and off-gas) mixing coefficient. 3D model of tundish and its top cover consists of 300195 control volumes. Optimization of position for burner heads and off- gas exhaust at tundish top cover brought uniform temperature field at inside of tundish refractory layer during transient process of preheating with minimal fuel consumption

Review of present and new developed heating systems for industrial furnaces

Visoko temperaturski procesi koji se odvijaju u indistrijskim pećima su energetski intenzivni procesi i predstavljaju pogodnu oblast za uvođenje inovacija koje se odnose na poboljšanje energetske efikasnosti i smanjenje emisije zagađujućih komponenata u procesu sagorevanja. U okviru rada biće dat pregled postojećih tehničkih rešenja sistema zagrevanja industrijskih peći kao i pregled novih konstrukcija visokoefikasnih gorionika koji su uspeli da zadovolje postavljene kriterijume u pogledu energetske efikasnosti procesa i zaštite životne sredine. Biće prikazana uporedna analiza tehničkih karakteristika regenerativnih, rekuperativnih i visokobrzinskih gorionika kao i analiza besplamenog modela sagorevanja. Novi sistem regenerativnih gorionika sa visokoefikasnim regenerativnim razmenjivačima toplote Pebble-bed tehnologije sa fluido-dinamičkim ventilom biće detaljno analiziran i prikazan u okviru ovog rada, kao i njegova moguća primena kod pojedinih tipova industrijskih peći.High temperature processes in industrial furnaces are energy intensive processes and suitable for implementation of new design that rises energy efficiency and reduce pollutant emission during combustion. The survey of present technical solutions of heating systems within industrial furnaces will be presented in this paper, as well as the survey of new developed high efficiency combustion systems design that perform established criteria in the frame of energy efficiency and environmental protection. Technical analysis of regenerative, recuperative and high velocity burners will be presented as well as flameless oxidation as a new principle of combustion. New system of regenerative burners with highly efficient regenerative heat exchangers based on Pebble-bed technology with fluid-dynamical valve will be analyzed with possible application in specific type of industrial furnaces

Review of present and new developed heating systems for industrial furnaces

Visoko temperaturski procesi koji se odvijaju u indistrijskim pećima su energetski intenzivni procesi i predstavljaju pogodnu oblast za uvođenje inovacija koje se odnose na poboljšanje energetske efikasnosti i smanjenje emisije zagađujućih komponenata u procesu sagorevanja. U okviru rada biće dat pregled postojećih tehničkih rešenja sistema zagrevanja industrijskih peći kao i pregled novih konstrukcija visokoefikasnih gorionika koji su uspeli da zadovolje postavljene kriterijume u pogledu energetske efikasnosti procesa i zaštite životne sredine. Biće prikazana uporedna analiza tehničkih karakteristika regenerativnih, rekuperativnih i visokobrzinskih gorionika kao i analiza besplamenog modela sagorevanja. Novi sistem regenerativnih gorionika sa visokoefikasnim regenerativnim razmenjivačima toplote Pebble-bed tehnologije sa fluido-dinamičkim ventilom biće detaljno analiziran i prikazan u okviru ovog rada, kao i njegova moguća primena kod pojedinih tipova industrijskih peći.High temperature processes in industrial furnaces are energy intensive processes and suitable for implementation of new design that rises energy efficiency and reduce pollutant emission during combustion. The survey of present technical solutions of heating systems within industrial furnaces will be presented in this paper, as well as the survey of new developed high efficiency combustion systems design that perform established criteria in the frame of energy efficiency and environmental protection. Technical analysis of regenerative, recuperative and high velocity burners will be presented as well as flameless oxidation as a new principle of combustion. New system of regenerative burners with highly efficient regenerative heat exchangers based on Pebble-bed technology with fluid-dynamical valve will be analyzed with possible application in specific type of industrial furnaces

Biomass gasification technology: The state of the art overview

The reduction of imported forms of energy, and the conservation of the limited supply of fossil fuels, depends up on the utilization of all other available fuel energy sources. Biomass is a renewable energy source and represents a valid alternative to fossil fuels. The abundance of biomass ranks it as the third energy resource after oil and coal. Moreover, when compared to fossil fuels, biomass fuels possess negligible sulphur concentrations, produce less ash, and generate far less emissions in to the air. In other words, biomass can deliver significant greenhouse gas reductions in electricity, heat and transport fuel supply. The energy in biomass may be realized by different thermochemical technologies of which gasification is most promising alternative routes to convert biomass to power/heat generation and production of transportation fuels and chemical feedstock. This paper deals with the state of the art biomass gasification technologies, evaluating advantages and dis-advantages, the potential use of the syngas and the application of the biomass gasification. Also, this paper provides short overview of the current status of the biomass gasification in Serbia