Production and Characterization of Biocoal for Coal-Fired Boilers

Author(s):  
Jaisen Mody ◽  
Roman Saveliev ◽  
Ezra Bar-Ziv ◽  
Miron Perelman

As part of PGE-EBC-MTU collaboration of the testing program to fire up to 100% of biocoal in the 600 MW Boardman boiler we produced samples from the seven biomass feedstock: Arundo Donax (AD), wheat waste, corn waste, woody hybrid poplar, and bark from hybrid poplar, woody pine, and bark from pine. The idea was to produce a few thousand tons of biocoal from woody and bark poplar for a 100% firing tests and from the other types to produce a 1000 tons of biocoal from each material that will be co-fired up to 10% with Powder River Basin coal. Biocoal is produced by a torrefaction which is a thermal process carried out in absence of oxygen. We have produced biocoal samples from the above biomass feedstock in two pilot facilities, one in Israel and another in Michigan. The torrefaction process comprises the following steps: (1) shredding and soil separation, (2) drying, (3) torrefaction, and (4) compaction to produce biocoal briquettes. Biocoal briquettes are essential for logistics, safety, operational, and economic considerations. The briquettes must be durable, water resistant and can be pulverized in common coal mills. The briquettes that we produced did indeed conform to these properties. A real operational challenge was working with absence of oxygen which essential for the torrefaction process as well as for safety considerations because the entire process occurs at elevated temperatures which biocoal can burn. A 30,000 t/year torrefaction facility has been constructed at the Boardman Plant site to produce biocoal required for the firing tests.

2014 ◽  
Vol 475 ◽  
pp. 116-126 ◽  
Author(s):  
Rodolfo Monterroso ◽  
Maohong Fan ◽  
Morris D. Argyle ◽  
Krisztina Varga ◽  
Darby Dyar ◽  
...  

Author(s):  
Jaisen Mody ◽  
Roman Saveliev ◽  
Ezra Bar-Ziv ◽  
Miron Perelman

As part of PGE-EBC-MTU collaboration of the testing program to fire up to 100% of biocoal in the 600 MW Boardman boiler we produced samples from the seven biomass feedstock: Arundo Donax (AD), wheat waste, corn waste, woody hybrid poplar, and bark from hybrid poplar, woody pine, and bark from pine. The various samples of biocoal were tested in a combustion chamber with the following results: (1) Biocoal was fired and burned providing temperature and gas concentration profiles similar to coal. (2) NOx emission from all biocoal originating from any type of biomass feedstock was found to be significantly lower than that from coal burning. (3) SOx emissions was found to correlate directly to sulfur content in the plant minerals, which is very small for all types of biomass tested. (4) Fouling was quite low for all biocoal tested, such that it can be handled with an optimized water cannons procedure. (5) Minerals in the biocoal were found to segregate from the carbon particles which means that slagging propensity can be predicted by the common slagging indices. (6) Carbon cycle analysis revealed significant reduction of CO2 when using these biomass feedstock types, particularly the bark types.


1993 ◽  
Vol 318 ◽  
Author(s):  
Q. Jiang ◽  
A. Chan ◽  
Y.-L. He ◽  
G.-C. Wang

ABSTRACTThe growth and chemical intermixing of submonolayer and a few monolayer thick Fe films on a Au(001) surface was studied by High Resolution Low Energy Electron Diffraction (HRLEED) technique. Through the analysis of the energy dependent angular profiles as a function of time, we obtained the distribution of islands and distribution of spacings during submonolayer growth. The interference of electron waves from different chemical elements in terraces at different heights in the surface contributes to the background intensity and broadening in the angular profiles of diffraction beams. A subsurface Fe capped by Au islands as a result of atomic place exchange was observed at the initial stage of monolayer growth. From the energy dependent angular profiles as a function of temperature, we determine the quantitative change of inhomogeneity length (∼20 Å) at the interface of ultrathin films at elevated temperatures due to intermixing.


1990 ◽  
Vol 213 ◽  
Author(s):  
G. E. Vignoul ◽  
J.M. Sanchez ◽  
J. K. Tien

ABSTRACTA basic characterization of the deformation behavior of Cr2Nb by microindention at ambient and elevated temperatures (up to 1400 °C) was undertaken. The microhardness of this system was seen to decrease with increasing temperature, from 1040 MPa at 25°C to 322 MPa at 1400 °C. Further, the microindention creep behavior of this system was studied by varying time on load at T = 1000 and 1200°C. Analysis of the data showed that m = 24 and Qapp = 477.61 kJ/mole. These unusually high values are indicative of the existence of an effective resisting stress against creep. When the data was fit against a microindention creep deformation law which was modified to incorporate an effective resisting stress term, it was determined that m = 4.5, Qcreep = 357 kJ/mole and the resisting stress term σr = 300 MPa.


2015 ◽  
Vol 46 (6) ◽  
pp. 2637-2645 ◽  
Author(s):  
Thi-Thuy Luu ◽  
Nils Hoivik ◽  
Kaiying Wang ◽  
Knut E. Aasmundtveit ◽  
Astrid-Sofie B. Vardøy

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