LOW-TEMPERATURE VORTEX (NTV) COMBUSTION TECHNOLOGY: EXPERIENCE AND POSSIBILITIES OF APPLICATION

1. NTV-energo Company Ltd.Russia, 195021, Saint-Petersburg,Polytechnicheskaya st., 24Tel/fax (7-812) 339-45-81, 339-88-63E-mail: ntvenergo@mail.ru LOW-TEMPERATURE VORTEX (NTV) COMBUSTION TECHNOLOGY: EXPERIENCE AND POSSIBILITIES OF APPLICATION

2. The history of NTV-technology creation and development Low temperature vortex combustion(NTV) technology and NTV furnace had been created by VictorPOMERANTSEV,distinguished soviet scientist in heat&power field, with the specialists from faculty of «Reactors and steam boilers machinery» at Polytechnical Institute of Leningrad. The wide verification of technology had been placed at power industry from 1970 till 1990 years (more than 30 boilers had been reconstructed). 1987 – the USSR Minenergo order developmentof boilers based on NTV-furnace with capacity 220, 420, 640 t/h. 1992 –NTV-energo Company was founded by specialists (RiPGSStPGPU), continuing with development and industrial application of NTV-technology.

3. Low temperaturevortex (NTV) technology This technology is protected by Russian, Eurasian and Ukrainian patents

4. Low temperaturevortex (NTV) technology of solud fuels combustion Principles of NTV-furnace operation: • Fuel combustion at multiple circulation of particles in the furnace. • Two combustion zones by height : vortex (1) and direct-flow (2). • Interaction of pulverized fuel - air flow with furnace bottom air at vortex zone 1. • “Active combustion area“ occupies complete vortex furnace zone. 2 2 1 1 This technology stands between direct-flow flame and circulating fluidized bed (CFB), enables all advantages of CFB, but greatly easier and cheaper

5. NTV-process enables: • increase of milling system capacity for 1,3 to 3,4 times depending of fuel and other; • extension of milling parts operation time; • improvement of milling system explosion safety; • simplification of fuel preparation system; • reduction of electricity consumption on solid fuel milling 1.Combustion of coarse particles • improvement of particulate precipitators efficiency 2.Fast pre-heating of fuel-air mixture flow • stable ignition and combustion; • cancelling of need for “fire support" with gas, light or heavy oil; • stable combustion process, independent from the load fluctuation and / or technical characteristics of fuel. • Intensifying of heat exchange (increase of evaporator walls heat exchange efficiency coefficient) 4.Unification of temperature field and decrease of maximal temperature in the core of fire up to 1000 to 1350 ˚С depending on fuel and furnace • possibility of boiler steam generating capacity increase for 15 to 20 % • absence of slagging and fouling of furnace and convective heat exchange surfaces; • decrease NOx emission for 20 to 70 % decrease of sulphur oxides- SOx emission up to level of70 %

6. Reference implementation of boilers with NTV technology(The company "NTV-Energo")

7. Referenceof boiler units on shoddyfuels Kumertau CHPP Nazarovskaya TPP CHPP-4, town Kirov NovomoskovskayaTPP 50…100% Dnom – operation without illumination

8. Characteristics of fuels used at NTV- combustion • lignite and hard coals • peat • oil shells • wood processing residues (bark, chip etc.) and micro biological production waste. Range of fuel characteristics used at NTV

9. NovomoskovskayaTPP Characteristics of plant • Boiler BKZ-220-100-4: • Steam generating capacity: 220 t/h; • Steam parameters: pressure — 9,8 МPа, temperature — 510оС

10. NovomoskovskayaTPP Problems prior boiler reconstruction: • Impossible boiler operation without flame support. • Very intensive slagging of boiler heating surfaces. • Limited steam generating capacity up to 160 t/hD=0,73Dnom. • High emission of SOx. • Bridging of coal in the Raw Coal Silo/ blocking of coal flow to feeder, puttying of raw coal scraper feeders

11. Scheme of NTV boilerBKZ 220-100 NovomoskovskayaTPP Scope of modernizing: • replacement of furnace from individual tubes type to membrane wall gas tight • replacement of down comers • replacement of thick refractory furnace walls with light thermal insulation blankets • replacement of burners

12. NovomoskovskayaTPP Scope of modernization: • replacement of pulverized coal and air ducts • reconstruction of mills’ classifiers • replacement of chain type coal feeders with two- screw type • modernizing of C&I system • overhaul of all other equipment at the level of general boiler overhaul

13. NovomoskovskayaTPP Results of boiler BKZ-220-9,9 modernizing When operates on coal: • Enabled stable boiler operation usingPodmoskovniy lignite without any flame support with auxiliary fuel. • Enabled operation without furnace walls slagging. • Coefficient of boiler thermal efficiency (gross) achieved: η = 88,4 % with Podmoskovniy (lignite), 90…92% with Intinskiy (coal). • Degree of sulphur oxides bounding, only with oxides in the coal ash, obtained at the level of about 47%. • Nitrogen oxides emission (recalculated on normal conditions and  = 1,4) obtained NOx=200 to 250 mg/m3 with Podmoskovniy (lignite), 450 mg/m3with Intinskiy (coal), norma - 470 mg/m3 . • Securing of explosion proof operation of pulverized coal system. • Pulverizing system capacity increase for 35%.

14. NovomoskovskayaTPP Results of boiler BKZ-220-9,9 modernizing When operates on gas: • Boiler capacity range – 96…230 t/h. • Coefficient of boiler thermal efficiency(gross) achievedη=94,5 % (with neighbour boiler BKZ-220 η=91,5 %). • Nitrogen oxides emission(recalculated on normal conditions and  = 1,4) obtained NOx=110…125  mg/m3 (with neighbour boiler BKZ-220 NOx=500…510  mg/m3).

15. CHPP-4,town Kirov Characteristics of plant • Boiler BKZ-210-140F: • Steam generating capacity: 210 t/h; • Steam parameters: pressure — 13,8 МPа, temperature — 545оС

16. Problems of boiler No. 9 when burning solid fuels CHPP-4,town Kirov low Coefficient of Boiler Thermal efficiency when burning hard coal (heat losses with mechanically unburned 12-17%); unstable combustion of solid fuel without flame support with natural gas or heavy oil; intensive slagging of heat exchange surfaces; fresh steam temperature lower for 20-30°C from designed when burning hard coal; bridging of coal in the Raw Coal Silo, puttying of raw coal scraper feeders; Emission of NOx, when burning hard coal, could come up to 1600 mg/m3.

17. Scope of modernizing of boiler station No. 9 CHPP-4, town Kirov Boiler drum Superheater I step ceiling part SuperheaterI step radiation part SuperheaterI step cold package Superheater II step System of downcomers Boiler steel structure Evaporator walls Pulverized coal burners Gas-heavy oil burners System of lower air System of tercialy air Prior reconstruction After reconstruction 17

18. CHP-4,town Kirov Two-screw type coal feeders in two-stage version applied to feed Raw Coal from Silos to mills. Each stage (batcher and conveyer) has individual frequency handling driving gear.

19. Low-Temperature Vortex Combustion: Implementation Main results of reconstruction of BKZ-210 Boiler of Kirov CHPP-4 Comparative factors before and after modernization * At joint burning of peat with black oil

20. MUP «SOUTHERNHEAT PLANT» townRubtsovsk Characteristics of plant • BoilersBKZ 85-13-250 No1 andNo2. • Steam generating capacity: 85 t/h. • Steam parameters: pressure — 9,8 МPа, temperature – 250…280ºС. • Kuznetskiy coal, grade SS.

21. MUP «SOUTHERNHEAT PLANT» townRubtsovsk Problems prior boiler reconstruction • Steam generating capacityrange 56,5…61,0 t/h, (66…72 % of nominal value). • Unstable ignition,flame support with heavy fuel oil. • Coefficient of boiler thermal efficiency(gross) in range74,5…81,1 %. • Slagging. • Bridging of coal in the Raw Coal Silo, blocking of raw coal scraper feeders.

22. MODERNIZATION OF THE BOILERBKZ-85. The main technical solutions New gastight NTV-furnace The new systemof control and automation New trace of pulverazed coal ducts Reconstruction of superheater Additional air ducts Furnace light weight insulation Replacement scraper feeders with double-screwfeeders New slag extractor

23. BoilerBKZ-85-13 withNTV-furnace • Performance • Enabled boiler operation at capacity range 55…105 t/h • without any flame support, without slagging, • using Kuznetskiy coal, grades SS, G, D, T • (Wr= 9–19%, Ar= 15–30%, Vdaf= 14–43%) • Maximum continuous steam load of the boiler: • 105 t/h (1,2Dnom) – for coals Т andSS; • 85 t/h (Dnom) – for coalsGandD • Efficiency (gross) 91,2–92,3%; • Nitrogen oxides emissionNOxin exhaust gasas 250–420 mg/nm3 (standart – 470 mg/nm3)

24. Nazarovskaya TPPUnit No.7, boiler P-49 Nazarovskaya State District Power Station Block # 7, boiler P-49 Design parameters: Steam capacity – 2 x 800 t/h, Pressure – 255 bar, Temperature – 545 C, Electric capacity – 500 Mwe Liquid slag-disposal Fuel: Brown Coal (characteristicson working mass) Humidity 40 % Ash content 5,4 % Sulfur content 0,3 % Nitrogen content 0,5 % Lower Heating Value 3260 ccal/kg 2011 – 2013 Reconstruction for Low-Temperature Vortex Combustion

25. Nazarovskaya Power Station : Boiler P-49 Operating difficulties Maximal steam capacity because of slag formation: no more than 0.76 Dnom Minimal steam capacity because of liquid slag-disposal: no less than 0.68 Dnom Ash fouling of heating surfaces, high gas tract pressure drop Low efficiency factor (gross) of the boiler (less then 86%) Increased emissions of nitrogen oxides NOx (close to 1200 mg/nm3)

26. Boiler P-49 Modernization. Main technical decisions New furnace Superheater reconstruction Dust bunkers and feeders reconstruction Networked economizer Burners Guiding inserts Bottom air system Cold gas recirculation

27. Boiler P-49 Modernization. Results obtained Power unit with the boiler P-49 parameters before and after reconstruction, comparison Tested fuels: Nazarovskiy brown coal Ipsha-Borodinskiy brown coal Berezovskiy brown coal

28. A comparison of the dimensions of the boiler P-49 with boilers, working on the Balkan lignites TPPGazko Boiler P-65 design: 300 MW qv = 70 kW/m3 fact: 220-230 MW qv = 51-53 kW/m3 + 61 m TPP Bitola Boiler P-64 design: 200 MW qv = 80 kW/m3 fact: 175 MW qv = 66 kW/m3 + 60,6 m Nazarovskaya TPP Boiler P-49 250 MW (1 body) qv = 213 kW/m3 + 38 m Traditional flameburning (PCF-combustion) NTV-burning

29. Boiler Ds-2140-25,5-570/570 with NTV furnace for unit of 660 MW at Erkovetsky coals Comparison of boiler design layouts in height at the same temperature at the exit of the furnaceϑ″f ≈ 1060 °С Circular furnace NTV furnace Boiler Ds-2140-25,5-570/570 With NTV-furnace Traditional combustion technology

30. With the help of NTV-technology for the first time in Russia solved the problems: 1. Combustion of high-moisture (Wr= 56...58%), low-calorie (Qri= 1700...2000 kcal/kg) brown coal and peat without gas or fuel oil illumination in the load range of 50...100% of nominal. 2. Combustion of high-ash (Ar= 35...45%), low-calorie (Qri= 1500...2000 kcal/kg), high-slag coals outside Moscow without gas or fuel oil illumination and without slag in the load range of 50...100% of nominal. 3. Ensure the preparation and combustion in one boiler plant of the whole range of Kuznetsky coal (grades T, SS, G, D) in the wide range of volatile (Vdaf= 15…43%). 4. Provision of preparation and combustion of heterogeneous fuels (coal, brown coal, peat and gas) in one boiler plant). 5. Burning of high-slag Kansko-Achinsk coals without slag in a small-sized combustion device (with a thermal stress of the furnace volume qv= 213 kW/m3). For comparison, the boiler P-67 Berezovskaya GRES, where the slag issues have not yet been resolved, has qv= 63 kW/m3. 6. Ensuring explosion safety of fuel preparation systems with air drying during their operation on high-reaction fuels.

31. NTV-combustion technology provides: • The possibility of transition to burning non-design fuel without reducing the load. • The preservation of the boiler capacity with the deterioration characteristics of the fuel. • The ability to work on multiple types of solid fuels in a wide range of changes in their thermal characteristics. • The boilers work throughout the operating load range at rated steam parameters without slagging. • The boilers work in load range 40...100% of nominal capacity without gas or fuel oil support. • Increase performances of coal pulverizing systems. • Improvement of explosion safety at coal pulverizing systems. • The increase in lifetime of mill working elements. • Reduction of NOx emissions in 2...3 times. • Reduction in emissions of SOx by 20...70%. • Increase the efficiency of ash precipitators.

32. NTV-combustion technology provides: • The possibility of reconstruction of existing boilers with an increase in their capacity • Possibility of delivery of new boilers with reduced dimensions. • The possibility of combustion of gas in the same boilers with an increase in efficiency by 1...3%. At gas combustion the guaranteed level of NOx emissions is not higher than 125 mg/Nm3. • At the same time, guaranteed solution of continuing supply of fuel to mills problems (elimination of bridging of fuel in bunkers, pressing coal in feeders) due to the installation of double screw feeders of raw coal. The cost of upgrades – 50...450 $/kWe

33. Possibility of application of NTV-technologies • modernization or replacement of old boilers in the existing cells with increased steam capacity and fulfillment of environmental standards • new construction with significant reduction of capital expenditure

34. Advantages of NTV-technology in comparison with a direct-flow flame for new boilers • Reducing the height of the boiler - significant savings in capital costs during construction. • Saving metal in manufacturing. • Ability to work without lighting in the entire load range (50...100%) on any fuel. • A significant simplification of system of preparation of fuel (the rejection of gas intake mines). • Ensuring regulatory emissions of NOx and SOx. • A significant reduction in capital costs (billions of rubles) with the installation of the national system of desulfurization, and operating costs. • Possibility of operation of the boiler on a wide range of fuels.

35. Comparison of NTV and CFB technologies Disadvantages of CFB technology: Impossibility of modernization of existing boilers Strict requirements for the particle size distribution of the fuel, which greatly complicates the preparation system High requirements for automation and culture of operation • Significant erosion of the lining of the furnace and cyclones • The presence of inert material and the need for constant recharge • The long duration of heating (layer heating) and, accordingly, greater consumption of gas/oil • Complicated ignition and the possibility of layer slagging • Maintaining modes difficulties in transients • Low reliability of the draining system of the fuel from the cyclone and external heat exchangers • NTV technology is devoid of these disadvantages

36. Comparison of NTV and CFB technologies Advantages of CFB technology: Deeper bindingSOx (until 90%). NTV technology – until70%. 2. The ability to work on low-reactive fuels the type of anthracite without backlight. NTV has no experience.

37. We propose joint work on the use of NTV technologies