scholarly journals An Assessment of the Efficiency and Emissions of a Pellet Boiler Combusting Multiple Pellet Types

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4465
Author(s):  
Marta Jach-Nocoń ◽  
Grzegorz Pełka ◽  
Wojciech Luboń ◽  
Tomasz Mirowski ◽  
Adam Nocoń ◽  
...  
Keyword(s):  
Corn Stover ◽  
Flue Gas ◽  
Heat Exchangers ◽  
Point Of View ◽  
Vertical Flow ◽  
Wood Pellets ◽  
Heating Capacity ◽  
Particulate Matter Emissions ◽  
Nominal Capacity ◽  
Climate Neutrality

With sustainable energy being the key to reaching climate neutrality, the utilization of non-wooden biomass is a necessity. This article compares the emissions and efficiency of combusting a number of types of agrobiomass and wood pellets. A comparison was made on a moving grate pellet burner mounted in a boiler, where flue gas had a vertical flow via two pass heat exchangers with turbulization elements. Tests were conducted on wood pellets (ENPlus), miscanthus straw pellets, sunflower husk pellets, and corn stover pellets. During combustion, both wood and miscanthus pellets met the PN-EN 303-5:2012 emission and efficiency requirements. Corn stover pellets met the requirement on the nominal capacity. Sunflower husk pellets are characterized by excessive CO and particulate matter emissions. Sunflower husk pellets were the most problematic fuel from the point of view of the results of this research. During combustion of the miscanthus straw pellets there was a need to decrease the nominal heating capacity due to ash sintering.

ADVANCED TYPES OF CHECKERWORK OF REGENERATIVE HEAT EXCHANGERS FOR GLASS FURNACES

2021 ◽  
pp. 3-10
Author(s):  
O. Koshelnik ◽  
S. Hoisan
Keyword(s):  
Phase Transition ◽  
Heat Exchangers ◽  
Heat Storage ◽  
Point Of View ◽  
Operating Conditions ◽  
Flue Gases ◽  
Regenerative Heat ◽  
Exchange Processes ◽  
Glass Furnaces ◽  
Refractory Bricks

One of the ways to increase glass furnaces energy efficiency is to apply heat exchangers for flue gases thermal potential utilization. Flue gases losses is up to 25-40 % of the total amount of heat supplied in the furnace. These losses are influences by such factors as fuel type, furnace and burners design and manufactured product type. Regenerative heat exchangers with various types of heat storage packing is more efficient for high-power furnaces. Such types of regenerator checkerwork as Cowper checkerwork, two types of Siemens checkerwork, Lichte checkerwork and combined checkerwork have already been sufficiently researched, successfully applied and widely used for glass furnaces of various designs. All of its are made of standard refractory bricks. Basket checkerwork and cruciform checkerwork that are made of fused-cast molded refractory materials have been widely used recently as well. Further improvement of regenerative heat exchangers thermal efficiency only by replacing the checkerwork does not seem possible unless their size being increased. But this enlarging is not always realizable during the modernization of existing furnaces. From this point of view heat storage elements with a phase transition, where metal salts and their mixtures are used as a fusible agent look promising for glass furnaces. These elements can accumulate additional amount of heat due to phase transition, which allows to increase significantly heat exchanger thermal rating without its size and operating conditions changing. However, it is necessary to carry out additional studies of this type of checkerwork dealing with analysis of complex unsteady heat exchange processes in regenerators and selection of appropriate materials that satisfy the operating conditions of regenerative heat exchangers so that the checkerwork can be widely used for glass furnaces.

scholarly journals Modified High Back-Pressure Heating System Integrated with Raw Coal Pre-Drying in Combined Heat and Power Unit

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2487 ◽  
Author(s):  
Heng Chen ◽  
Zhen Qi ◽  
Qiao Chen ◽  
Yunyun Wu ◽  
Gang Xu ◽  
...  
Keyword(s):  
Power Generation ◽  
Flue Gas ◽  
Waste Heat ◽  
Heating System ◽  
Combined Heat And Power ◽  
Back Pressure ◽  
Coal Consumption ◽  
Heating Capacity ◽  
Boiler Efficiency ◽  
Saving Effect

A conceptual high-back pressure (HBP) heating system cooperating raw coal pre-drying for combined heat and power (CHP) was proposed to improve the performance of the HBP-CHP unit. In the new design, besides of heating the supply-water of the heating network, a portion of the exhaust steam from the turbine is employed to desiccate the raw coal prior to the coal pulverizer, which further recovers the waste heat of the exhaust steam and contributes to raising the overall efficiency of the unit. Thermodynamic and economic analyzes were conducted based on a typical 300 MW coal-fired HBP-CHP unit with the application of the modified configuration. The results showed that the power generation thermal efficiency promotion of the unit reaches 1.7% (absolute value) owing to suggested retrofitting, and meanwhile, the power generation standard coal consumption rate is diminished by 5.8 g/kWh. Due to the raw coal pre-drying, the energy loss of the exhaust flue gas of the boiler is reduced by 19.1% and the boiler efficiency increases from 92.7% to 95.4%. The impacts of the water content of the dried coal and the unit heating capacity on the energy-saving effect of the new concept were also examined.

Comparison of reduction efficiency of woven straw for entrained emissions of particulate matter with diameters less than 10 µm (PM10) and less than 2.5 µm (PM2.5) from exposed areas at construction sitesA paper submitted to the Journal of Environmental Engineering and Science.

2010 ◽  
Vol 37 (5) ◽  
pp. 787-795 ◽  
Author(s):  
Kuo-Tung Su ◽  
Yu-Min Chang ◽  
Wei-Hsing Hu ◽  
Shiao-Shing Chen ◽  
Chao-Hsiung Wu ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Engineering Application ◽  
Point Of View ◽  
Construction Sites ◽  
Coverage Ratio ◽  
Average Value ◽  
Wind Speeds ◽  
Particulate Matter Emissions ◽  
Approach Zero ◽  
Tunnel System

From an engineering application point of view in reducing fugitive particulate matter emissions, this paper presents experimental data comparing the efficiency of woven straw at reducing entrained emissions of particulate matter with diameters less than 10 µm (PM10) with that for particulate matter with diameters less than 2.5 µm (PM2.5) at construction sites. A series of field-analogous experiments were carried out to continuously measure PM10 and PM2.5 using laser particle monitors in an artificial wind tunnel system. It was found that the efficiency of woven straw at reducing either PM10 or PM2.5 is significantly dependent on the woven straw coverage ratio. The maximum reduction efficiencies for PM10 and PM2.5 are about 40% and 12%, respectively. Note that the reduction efficiencies approach zero as the coverage ratio is less than about 40%. Total elimination of PM2.5 and PM10 emissions is not possible, even using full-coverage woven straw. Reduction of PM2.5 emissions is less efficient than that of PM10 emissions using woven straw, and this trend is likely more obvious with an increase in the woven straw coverage ratio. The ratio of reduction efficiencies (R) between PM2.5 and PM10 for woven straw decreased slightly with an increase in the woven straw coverage ratio. Overall, for wind speeds of 0.5–3.0 m/s, silt contents of 4.8%–21.0%, and soil moisture contents of 10%–30% as used in this work, the average value of R is 0.31. The effects of wind velocity, silt content, and moisture content on the reduction efficiencies are also discussed.

scholarly journals Investigation of Pellet Properties Produced from a Mix of Straw and Paper Sludge

2020 ◽  
Vol 10 (16) ◽  
pp. 5450 ◽  
Author(s):  
Radovan Nosek ◽  
Sebastian Werle ◽  
Aleksandra Borsukiewicz ◽  
Agnieszka Żelazna ◽  
Grzegorz Łagód
Keyword(s):  
Melting Temperature ◽  
Heat Exchangers ◽  
Fossil Fuels ◽  
Plant Biomass ◽  
Biomass Combustion ◽  
Paper Sludge ◽  
Wood Pellets ◽  
Positive Effects ◽  
Negative Impacts ◽  
Global Energy Consumption

Global energy consumption is increasing every year, and, despite their many negative impacts, fossil fuels are a major source of energy, but their reserves are gradually depleting. One of the promising but underutilized resources is plant biomass (phytomass). The main problem of plant biomass combustion is the low melting temperature of ash, but there are also problems with corrosion of heat exchangers and clogging of heat-exchanging surfaces. This work is concerned with the production of straw pellets in order to increase the melting temperature of ash by adding an additive. The paper sludge contains substances that can increase the melting point of ash and was therefore added to the pellet samples. This additive was mixed with straw in ratios from 90:10, 80:20 and 70:30 (straw/paper sludge). The use of paper sludge showed positive effects on increasing the melting temperature of the ash samples. The deformation temperature of the ash has already risen from 1020 to 1260 °C after the addition of 10% sludge, which is comparable to wood pellets.

scholarly journals The Utilization of Plum Stones for Pellet Production and Investigation of Post-Combustion Flue Gas Emissions

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5107 ◽  
Author(s):  
Magdalena Dołżyńska ◽  
Sławomir Obidziński ◽  
Jolanta Piekut ◽  
Güray Yildiz
Keyword(s):  
Food Waste ◽  
Flue Gas ◽  
Energy Systems ◽  
Power Demand ◽  
Wood Pellets ◽  
Heating Value ◽  
Waste Sample ◽  
Lower Heating Value ◽  
Lower Heating ◽  
Ecodesign Directive

Agri-food waste is generated at various food cycle stages and is considered to be a valuable feedstock in energy systems and chemical syntheses. This research identifies the potential and suitability of a representative agri-food waste sample (i.e., plum stones) as a solid fuel. Ground plum stones containing 10, 15, and 20 wt.% of rye bran were subjected to pelletization. The pelletizer was operated at 170, 220, and 270 rpm, and its power demand for the mixture containing 20 wt.% of rye bran was 1.81, 1.89, and 2.21 kW, respectively. Such pellets had the highest quality in terms of their density (814.6 kg·m−3), kinetic durability (87.8%), lower heating value (20.04 MJ·kg−1), and elemental composition (C: 54.1 wt.%; H: 6.4 wt.%; N: 0.73 wt.%; S: 0.103 wt.%; Cl: 0.002 wt.%; O: 38.2 wt.%). Whole plum stones and pellets were subjected to combustion in a 25 kW retort grate boiler in order to determine the changes in the concentrations of NO, SO2, CO, CO2, HCl, and O2 in the post-combustion flue gas. Collected results indicate that plum stone–rye bran pellets can serve as effective substitutes for wood pellets in prosumer installations, meeting the Ecodesign Directive requirements for CO and NO.

Numerical Study of Transport Membrane Condenser Heat Exchangers

2016 ◽  
Author(s):  
Esmaiil Ghasemisahebi ◽  
Soheil Soleimanikutanaei ◽  
Cheng-Xian Lin ◽  
Dexin Wang
Keyword(s):  
Flue Gas ◽  
Heat Exchangers ◽  
Ceramic Membrane ◽  
Waste Heat ◽  
Numerical Study ◽  
Tube Bundle ◽  
Pure Water ◽  
Separation Mechanism ◽  
Low Grade ◽  
Water Recovery

In this study tube bundle Transport Membrane Condenser (TMC) has been studied numerically. The tube walls of TMC based heat exchangers are made of a nano-porous material and has a high membrane selectivity which is able to extract condensate pure water from the flue gas in the presence of other non-condensable gases (i.e. CO2, O2 and N2). Low grade waste heat and water recovery using ceramic membrane, based on separation mechanism, is a promising technology which helps to increase the efficiency of boilers and gas or coal combustors. The effects of inclination angles of tube bundle, different flue gas velocities, and the mass flow rate of water and gas flue have been studied numerically on heat transfer, pressure drop and condensation rates. To assess the capability of single stage TMC heat exchangers in terms of waste heat and water recovery at various inlet conditions, a single phase multi-component model is used. ANSYS-FLUENT is used to simulate the heat and mass transfer inside TMC heat exchangers. The condensation model and related source/sink terms are implemented in the computational setups using appropriate User Defined Functions (UDFs).

The Flow Characteristics of Flue Gas Between the Fins of a Single Spiral Finned Tube

2005 ◽  
Author(s):  
Fengzhong Sun ◽  
Yuetao Shi ◽  
Zhihang Han ◽  
Yang Liu ◽  
Xinyuan Huang ◽  
...  
Keyword(s):  
Experimental Research ◽  
Flue Gas ◽  
Heat Exchangers ◽  
Flow Characteristics ◽  
Finned Tube ◽  
Finned Tubes ◽  
Cold State ◽  
State Test

The spiral finned tubes are used as the substitute of bare tubes in heat exchangers, which is an effective method to reduce abrasion and fouling in boilers. The cold state test with PDA system has been made to study the distribution of granule concentration between fins. This experimental research has laid the foundation of analysis for further study why the spiral finned tube can reduce abrasion and fouling.

scholarly journals Efficiency of Installation of an Additional Gas-Air Heat Exchanger When Operating a Steam Boiler on Gas and Liquid Fuel

2021 ◽  
Vol 2096 (1) ◽  
pp. 012011
Author(s):  
F Bakirov ◽  
E Ibragimov
Keyword(s):  
Flue Gas ◽  
Heat Exchangers ◽  
Liquid Fuel ◽  
Fuel Efficiency ◽  
Operating Mode ◽  
Payback Period ◽  
Fuel Oil ◽  
Technical Solution ◽  
Steam Boiler ◽  
Gas Temperature

Abstract The article presents the results of calculating the efficiency of reconstruction of the gas and air paths of a steam boiler when working on gas and liquid fuel due to the installation of additional gas-air heat exchangers. Due to the utilization of the thermal energy of the flue gases in the newly installed heat exchangers, the air is heated in front of the boiler air heaters and the fuel efficiency is increased by increasing the boiler efficiency. The increase in the efficiency of the "gross" boiler during the operation of the considered TGM-84 boiler on fuel oil with an average annual operating mode was 2.81 %. The flue gas temperature after the boiler air heaters was 178 °C, and the air temperature at the inlet to the air heaters was 99 °C at the average annual load of the boiler, which ensures an almost corrosion-free operation of the air heater packing. It is revealed that when the liquid fuel boilers, installation of new heat exchangers and their strapping on the side of the air and flue gas has a shorter payback period than the boiler gas fired. The simple payback period of the considered technical solution was 6,82 years when working on gas fuel and 1,35 years when working on liquid fuel.

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