Biomass gasification syngas

Mermelstein J, MiUan M, Brandon NP (2011) The interaction of biomass gasification syngas components with tar in a solid oxide fuel cell and operational conditions to mitigate carbon deposition on nickel-gadolinium doped ceria anodes. J Power Sources 196 5027-5034... 

Whilst the basic process for generation and conversion of syngas is well established, production from biomass poses several challenges. These centre on the co-production of tars and hydrocarbons during the biomass gasification process, which is typically carried out at 800 °C. Recent advances in the production of more robust catalysts and catalytic membrane reactors should overcome many of these challenges. 

The heatpipe reformer process concept for hydrogen-rich syngas production. (Reproduced from Karellas, S., Metz, T., Kuhn, S., and Karl, J., Online analysis of the tar content of the product gas from biomass gasification. Application on the BIOHPR. 14th European Biomass Conference Exhibition, Biomass for Energy, Industry and Climate Protection, ETA-Renewable Energies, Paris, 2005. With permission.)... 

The increased efficiency in IGCC systems translates into environmental benefits because emissions per unit energy produced are lower. This includes CO, NOx, SOx, C02, and particulates. NOx and SOx emissions are inherently lower in biomass IGCC systems because biomass fuels tend to have low N and S contents to start with, and gas cleanup and conditioning in biomass gasification systems removes these impurities before the syngas is combusted in the gas turbine. The same is true for particulates. C02 emissions are effectively zero, because biomass is a renewable fuel. 

Syngas composition, most importantly the H2/CO ratio, varies as a function of production technology and feedstock. Steam methane reforming yields H2/CO ratios of three to one whereas coal and biomass gasification yields ratios closer to unity or lower. Conversely, the required properties of the syngas are a function of the synthesis process. Fewer moles of product almost always occur when H2 and CO are converted to fuels and chemicals. Consequently, syngas conversion processes are more thermodynamically favorable at higher H2 and CO partial pressures. The optimum pressures depend on the specific synthesis process. 

Another approach to biomass-derived chemical production is the two-plat-form concept where the production of syngas (synthesis gas) from biomass gasification, or other technologies, is used to produced methanol or hydrocarbons through Fischer-Tropsch technology. ... 

With FI MH purification, hydrogen recovery does not strongly depend on reformate quality, and hence is the preferred option with ATRs and purification of syngas streams from renewable sources (e.g. biomass gasification or pyrolysis). 

Gas-phase, steam cracking reactions dominate the chemistry of biomass gasification. At temperatures above 650°C, these reactions proceed very rapidly and generate a hydrocarbon rich syngas containing commercially interesting amounts of ethylene, propylene, and methane. Increased pressure appears to inhibit the gasification process. 

Fig. 13.1 Hydrogen in the energy system of the futine [1]. Pie-c

In this chapter, a brief description of the main bio-SNG facilities and projects in Europe is presented as well as the main process units (gasification, gas cleaning and methana-tion) integrated for bio-SNG production. Therefore, a case study for bio-SNG production is modeled by using the CHEMCAD 6.3.1.4168 software. Two process technologies, a fixed (adiabatic case) or fluidized (isothermal) bed methanation reactors are considered, while three different product gas compositions from real biomass gasification data are fed as input syngas for the modeled system. Einally, CH4 yield and chemical efficiency of the different cases are compared and discussed. 

This chapter focuses on steam gasification processes carried out in fluidized bed reactors for the production of H2-rich syngas. Fixed bed down-draft and up-draft gasifiers have also been used, but these are restricted to small-scale applications of biomass gasification with air and are not amenable to scale-up or to in-situ gas purification they are also difficult to operate under steady-state and intrinsically safe conditions. 

As discussed earlier, syngas produced by biomass gasification suffers from the presence of a range of contaminants particulates, tar as well as various trace components. These can harm the catalytic media that in the advanced conditioning treatments, to be discussed later in this chapter, are necessary for the efficient conversion of tars and the adjustment... 

Experimental tests on the filtration of syngas from biomass gasification at temperatures close to 800 °C have shown promising results [63]. However, additional long-term trials are still required to confirm stable filtration under industrial conditions of operation. 

Gasification Conversion of coal, petroleum, or biomass into syngas. 

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