Pilot-scale combustion studies with kraft lignin in a powder burner and a CFB boiler

Abstract

Processes have been developed to produce a solid biofuel with high energy density and low ash content from kraft lignin precipitated from black liquor. Pilot-scale tests of the lignin biofuel were carried out with a 150 kW powder burner and a 12 MW circulating fluidized bed (CFB) boiler. Lignin powder could be fired in a powder burner with good combustion performance after some trimming of the air flows to reduce swirl. Lignin dried to 10% moisture content was easy to feed smoothly and had less bridging tendencies in the feeding system than did wood/bark powder. In the CFB boiler, lignin was easily handled and cofired together with bark. Although the filter cake was broken into smaller pieces and fines, the combustion was not disturbed. When cofiring lignin with bark, the sulfur emission increased compared with bark firing only, but most of the sulfur was captured by calcium in the bark ash. Conventional sulfur capture also occurred with addition of limestone to the bed. The sulfur content in the lignin had a significantly positive effect on reducing the alkali chloride content in the deposits, thus reducing the high temperature corrosion risk.

Energy efficiency challenges in pulp and paper manufacturing: A tutorial review

“…Once the lignin has been separated, there are several potential uses for it, though many of the higher-value potential uses face large obstacles that inhibit their industrial implementation. As a low-value use, the lignin can be co-fired with bark and other biomass in a power boiler (Berglin et al 2010). Since such a boiler does not have to be engineered for combustion of black liquor, it can be cheaper to construct and more efficient to run (Demirbas 2005;Khan et al 2009;Saidur et al 2011).…”

Study of the processes of joint grinding and ignition of coal with wood raw materials

“…To date, a situation has arisen where progress in the engineering field of designing burner devices is somewhat ahead of the technology for obtaining fuel for the developed power plants. Thus, efficient equipment for combustion of finely dispersed fuels has been created, capable of utilizing even lignin in an environmentally friendly mode -the most large-tonnage and "problematic" waste of pulp and paper production [1], but fuel preparation technologies can only offer energy-efficient ultra-fine grinding or an increase in fuel calorific value. adding fuel oil, waste oil or, at best, micronized coal.…”

The Effect of Thermomechanical Pretreatment on the Structure and Properties of Lignin-Rich Plant Biomass

“…Lignocellulosic materials, a common agricultural and wood industry waste, have great potential as renewable feedstock that can be converted into platform chemicals, second-generation biofuels, and a number of other high-demand chemical products [1]. Integrated biorefinery, which comprises the conversion of polysaccharides to low-molecular-weight carbohydrates [2][3][4] and the use of lignin as a component of high-energy fuel [5][6][7] or core-shell-structured sorbents with humic acids [8], is the most promising green approach in the refinery of plant biomass. Because of its complex supramolecular structure, the lignocellulosic biomass requires mechanical [9][10][11], thermal [12][13][14] or chemical pretreatment [15][16][17].…”