100% Test Burn of Torrefied Wood Pellets at a Full-Scale Pulverized Coal Fired Utility Steam Generator

2018 ◽  
Author(s):  
Rod Hatt ◽  
David A. T. Rodgers ◽  
Randy Curtis
Keyword(s):  
Electrostatic Precipitator ◽  
Combustion Efficiency ◽  
Pulverized Coal ◽  
Powder River Basin ◽  
Wood Production ◽  
Wood Pellets ◽  
Front End ◽  
Combustion Emissions ◽  
And Storage ◽  
Test Fuel

Portland General Electric’s (PGE) Boardman plant is a nominal 600 megawatt (MW) coal fired unit that burns sub-bituminous Powder River Basin (PRB) coal from Wyoming. This paper will cover the experience and results of PGE’s Boardman plant operating on 100% torrefied wood (TW) pellets at 255 MW consuming almost 5000 tons of pellets. Results were positive and include suitable handing after inclement weathering for months. Pulverizers were able to handle the TW pellets with adjustments, resulting in near 100% combustion efficiency. Particulates were controlled with an electrostatic precipitator (ESP). Topics investigated include torrefied wood production, fuel handling and storage on the front end of the test. Fuel handling, pulverization, combustion, emissions, and ESP performance were monitored during the test and are reported here. Several one mill tests were conducted prior to the 100% test to evaluate and improve mill performance. This test showed that a pulverized coal (PC) boiler can operate on 100% TW fuel with minimal operational changes.

Woody Biomass Co-Firing in Pulverized Coal Fired Boilers

2011 ◽  
Author(s):  
Luther M. Raatikka
Keyword(s):  
Heat Input ◽  
Heat Rate ◽  
Woody Biomass ◽  
Electrical Energy ◽  
Pulverized Coal ◽  
Wood Pellets ◽  
Capital Costs ◽  
Auxiliary Power ◽  
Boiler Efficiency ◽  
Fuel Costs

With legislation requiring utilities to produce a significant fraction of their electrical energy with renewable fuel supplies, it is anticipated that cofiring biomass in large utility boilers will become increasingly popular. Boilers that are designed to burn pulverized coal (PC) can typically burn woody biomass at up to 5% of the rated heat input. An 800 MW PC-fired unit could, therefore, produce up to 40 MW of renewable energy with biomass co-firing. The generating plant may experience a net capacity de-rating whenever biomass is co-fired. This potential reduction in net plant output may be attributed to reduced boiler efficiency and additional auxiliary power requirements. Biomass fuel handling related auxiliary power requirements are dependent upon the form in which biomass is delivered to the plant. Preparation of woody biomass for co-firing in large PC-fired boilers is typically performed onsite with hammer mills or by off-site processing. For an 800 MW unit, onsite fuel size reduction will usually result in an incremental increase in auxiliary power of 3–4 MW, whereas the use of pre-processed biomass such as wood pellets will require a minimal increase in parasitic load. However, delivered fuel costs for raw wood requiring onsite processing are at least 60% lower than that of densified biomass on a heat input basis. This paper includes an economic comparison of co-firing woody biomass that is processed onsite by direct injection vs. co-firing densified woody biomass by co-milling in a large PC-fired boiler. This comparison will consider delivered fuel costs, capital costs, CO2 emissions and impacts upon boiler efficiency and net heat rate.

Retrofitting 25T/h Pulverized Coal-Fired Boiler Into 35T/h Circulating Fluidized Bed Boiler for Burning Mixture of Coal and Bagasse

2005 ◽  
Author(s):  
Han-Ping Chen ◽  
Xian-Hua Wang ◽  
Shi-Hong Zhang ◽  
De-Chang Liu ◽  
Yu-Hua Lai ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Combustion Efficiency ◽  
Economic Benefits ◽  
Pulverized Coal ◽  
Industrial Wastes ◽  
Pollutant Emission ◽  
Fluidized Bed Combustion ◽  
Circulating Fluidized Bed Boiler ◽  
Combustion Technology

In China, there are a large number of pulverized coal-fired industrial boilers, whose steam capacities are usually relatively small. These boilers can burn only high-grade coal and have low combustion efficiency. Furthermore, the combustion emissions, such as SO2 and NOx, pollute the environment severely. Therefore it is very important and urgent to adopt economically efficient and environmentally friendly technologies to retrofit these boilers. At the same time, there are many industrial wastes, such as bagasse, wood waste, rubbish, petroleum coke and so on, need burning disposal in China. Fluidized bed combustion technology is a kind of clear combustion technology, which has many advantages, such as excellence fuel flexibility, high combustion efficiency, low pollutant emission and good turndown capability etc. So, adopting fluidized bed combustion technology, retrofitting pulverized coal-fired boiler into fluidized bed boiler can realize pure burning various wastes or co-firing with coal, which should have great economic benefits and social benefits. And the application prospect of the method is also extensive. The State Key Laboratory of Coal Combustion has successfully retrofitted a 25t/h pulverized coal-fired boiler into circulating fluidized bed boiler with in-bed tubes and downward exhaust cyclone. The retrofitted boiler can burn mixture of coal and bagasse and the steam capacity reaches 35t/h. This paper presents the retrofitting measures and the operation status of the boiler after retrofitting.

scholarly journals Second-Generation Lignocellulosic Supportive Material Improves Atomic Ratios of C:O and H:O and Thermomechanical Behavior of Hybrid Non-Woody Pellets

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4219
Author(s):  
Bruno Rafael de Almeida Moreira ◽  
Ronaldo da Silva Viana ◽  
Victor Hugo Cruz ◽  
Anderson Chagas Magalhães ◽  
Celso Tadao Miasaki ◽  
...  
Keyword(s):  
Second Generation ◽  
Mechanical Stability ◽  
Pilot Scale ◽  
Preliminary Evidence ◽  
Thermomechanical Behavior ◽  
Wood Pellets ◽  
Residual Biomass ◽  
Second Generation Bioethanol ◽  
Solid Biofuels ◽  
And Storage

Pellets refer to solid biofuels for heating and power. The pellet’s integrity is of great relevant to ensure safe and effective transportation and storage, and comfort to stakeholders. Several materials that are supportive, whether organic and inorganic, to pellets exist. However, no work in the literature is linking making hybrid non-wood pellets with addition of residual biomass from distillation of cellulosic bioethanol, and this requires further investigations. Figuring out how effective this challenging agro-industrial residue could be for reinforcing non-wood pellets is accordingly the scientific point of this study focusing on management of waste and valorization of biomass. The pilot-scale manufacturing of hybrid pellets consisted of systematically pressing sugarcane bagasse with the lignocellulosic reinforcement at the mass ratios of 3:1, 1:1, and 1:3 on an automatic pelletizer machine at 200 MPa and 125 °C. Elemental contents of C and H, durability, and energy density all increased significantly from 50.05 to 53.50%, 5.95 to 7.80%, 95.90 to 99.55%, and 28.20 to 31.20 MJ kg−1, respectively, with blending the starting material with the reinforcement at 1:3. Preliminary evidence of residual biomass from distillation of second-generation bioethanol capable of highly improving molecular flammable/combustible properties, mechanical stability, and fuel power of composite non-wood pellets exist.

scholarly journals Convergent-Divergent Injection Lance for the Enhancement of Combustion Efficiency of Pulverized Coal at Blast Furnace

2016 ◽  
Vol 56 (5) ◽  
pp. 770-776 ◽  
Author(s):  
Ryota Murai ◽  
Yusuke Kashihara ◽  
Akinori Murao ◽  
Michitaka Sato
Keyword(s):  
Blast Furnace ◽  
Combustion Efficiency ◽  
Pulverized Coal

Experimental study of the combustion efficiency and formation of NOx in an industrial pulverized coal combustor

2004 ◽  
Vol 28 (6) ◽  
pp. 511-520 ◽  
Author(s):  
Li ZhengQi ◽  
Yang LongBin ◽  
Qiu PengHua ◽  
Sun Rui ◽  
Chen LiZhe ◽  
...  
Keyword(s):  
Experimental Study ◽  
Combustion Efficiency ◽  
Pulverized Coal
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