Search

Biorefinery as a concept for polygeneration of various bio-based materials, fuels and chemicals has been more and more attractive. This concept is applied to the thermomechanical pulp (TMP) and paper industry in the present study to evaluate the possibility of co-production of substitute natural gas (SNG), electricity and district heating (DH) in addition to mechanical pulp and paper. In TMP mills, wood and biomass residues are commonly utilized for electricity and steam production through an associated combined heat and power (CHP) plant. This CHP plant is designed to be replaced by a biomass-to-SNG (BtSNG) plant including an associated heat and power centre. Implementing BtSNG in a mechanical pulp production line might improve the profitability of a TMP mill and also help to commercialize the BtSNG technology by taking into account of some key issues such as, biomass availability, heat utilization etc.. A TMP+BtSNG mathematical model is developed with ASPEN Plus. [ABSTRACT FROM AUTHOR]

The most prohibitive aspect with the commercialisation of biomass gasification technology is tar fouling of the product gas. The presence of tar impacts the efficiency of gasification systems and compromises gas quality, rendering it less useful for some downstream applications sensitive to gas quality. Various tar detection methods are reported in the literature which can be differentiated into offline and online techniques. However, offline techniques are found to be time consuming, expansive and require sufficient instrumentation and knowledge to achieve reliable results. Recent advances in online tar detection based on spectral information of individual tar component have attracted much research attention. Among these, fluorescence spectroscopy is a highly promising technique for the provision of distinctive, non-invasive and real time data collection for tar levels which can be easily installed on gasification product gas streams. This paper presents the initial work on developing a low cost tar detection system based on LED induced fluorescence. The detection system mainly consists of a photomultiplier tube (PMT), LED (emission wavelength of 280 nm) and 300 nm longpass colour glass filter. Initial experiments have been carried out with different concentrations (0 to 100 wt%) of phenol (used as a model tar compound) and bio-oil samples from an in-house, downdraft (throated) fixed bed gasification system. The results show a linear increase of fluorescence with phenol and the gasifier bio-oil at different concentrations. [ABSTRACT FROM AUTHOR]

This paper presents a non-stoichiometric equilibrium model for the simulation of biomass downdraft gasifiers. The chemical equilibrium is determined by minimizing the Gibbs free energy. Five elements characterize the biomass and 15 chemical species are considered in the syngas. The model calculates the lower heating value of the syngas and the relative abundances of gasification products. An advantage of this model is that it can easily calculate not only the concentrations of the main gasification products, but also the concentrations of minor product, especially the pollutant chemical species containing Nitrogen and Sulfur. To analyse the model behaviour, a sensitivity analysis on process parameters is presented. The model is validated by comparing its results with the results of simulation carried out with a stoichiometric model and with experimental data found in literature. Finally, the model is applied to the study of the gasification of forest waste. [ABSTRACT FROM AUTHOR]

The use of biomass waste in high efficient low pollutants emissions micro-cogeneration plants overpasses the main biomass barriers: competition with the food and material uses, dispersion of a low energy density fuel and high emissions. Evaluations of present technical aspects, economic benefits and their future projections are very important to bring into focus the needs of the technological development of this energy application. This paper is focused on a small (250 kWth) steam gasification fluidized bed and hot gas conditioning system, contextualized in the case study of a farm situated near Rome. Since most of usable biomass waste comes from agriculture, appraisal of applicability to real rural contexts deserves closer examination, considering the necessity of a small size solution as well. A feasibility study of an actual employment of this energy system has included: biomass availability and energy consumption analysis, biomass and gasification tests, power plant sizing, using experimental data and chemicad simulation. Finally an economic analysis has been carried out by varying the main economic parameters. Olive pruning are confirmed as very suitable, and in this case, able to satisfy the farm energy consumption. Global electrical efficiency of 25% can be achieved without any auxiliary fuel consumption. Consumption of 60% of the heat generated are required, meanwhile investment and biomass costs up to 8000 €/kW and 100 €/t can be sustained, especially if the farm electricity cost are higher than 0.15 €/kWh. [ABSTRACT FROM AUTHOR]

A gasification plant was designed and built to test syngas production from biomass for electricity generation on microscale. The plant is mainly composed by a downdraft reactor, a gas cleaning section with a cyclone and a wet scrubber, a blower for syngas extraction and an ICE (Internal Combustion Engine, Lombardini LGA 340), equipped with an alternator. A small quantity of producer was also eventually sent to a button cell SOFC (Solid Oxide Fuel Cell) for preliminary characterization. The plant was tested in a preliminary experimental campaign to evaluate mass and energy balances and process efficiency. Woody biomass was used and the producer gas firstly passed through impingers bottles, to condense and measure tar concentration (according to CEN/TS 15439), and then the remaining uncondensed gas was analyzed with a micro-GC (Gas Chromatograph). The paper presents and discusses the results of the preliminary tests carried out. [ABSTRACT FROM AUTHOR]

The use of biomass waste in high efficient low pollutants emissions micro-cogeneration plants overpasses the main biomass barriers: competition with the food and material uses, dispersion of a low energy density fuel and high emissions. Evaluations of present technical aspects, economic benefits and their future projections are very important to bring into focus the needs of the technological development of this energy application. This paper is focused on a small (250 kWth) steam gasification fluidized bed and hot gas conditioning system, contextualized in the case study of a farm situated near Rome. Since most of usable biomass waste comes from agriculture, appraisal of applicability to real rural contexts deserves closer examination, considering the necessity of a small size solution as well. A feasibility study of an actual employment of this energy system has included: biomass availability and energy consumption analysis, biomass and gasification tests, power plant sizing, using experimental data and chemcad simulation. Finally an economic analysis has been carried out by varying the main economic parameters. Olive pruning are confirmed as very suitable, and in this case, able to satisfy the farm energy consumption. Global electrical efficiency of 25% can be achieved without any auxiliary fuel consumption. Consumption of 60% of the heat generated are required, meanwhile investment and biomass costs up to 8000 €/kW and 100 €/t can be sustained, especially if the farm electricity cost are higher than 0.15 €/kWh. [ABSTRACT FROM AUTHOR]

This paper provides a new approach for using the by-products of bio-oil and bio-char, which are derived from the biomass gas station in rural China. Bio-slurry was prepared by blending bio-oil with different concentrations of bio-char (0-20 wt.%), and the production of hydrogen from steam gasification of bio-slurry was investigated. It is found that the bio-slurry fuels prepared from the carbonization products have better fuel properties including calorific value and stability in comparison to those prepared using fast pyrolysis products. The results demonstrate that the apparent viscosities of bio-slurry vary with bio-char contents (in the range of 0 to 20 wt.%) and temperature (from 7 o C to 50 o C). In addition, the bio-slurry exhibits good stability. Steam gasification of bio-slurry can produce hydrogen-rich gas, and the high gas yields (especially for H 2 and CO) are obtained at around 900 o C. [ABSTRACT FROM AUTHOR]

This paper provides a new approach for using the by-products of bio-oil and bio-char, which are derived from the biomass gas station in rural China. Bio-slurry was prepared by blending bio-oil with different concentrations of biochar (0-20 wt.%), and the production of hydrogen from steam gasification of bio-slurry was investigated. It is found that the bio-slurry fuels prepared from the carbonization products have better fuel properties including calorific value and stability in comparison to those prepared using fast pyrolysis products. The results demonstrate that the apparent viscosities of bio-slurry vary with bio-char contents (in the range of 0 to 20 wt.%) and temperature (from 7 °C to 50 °C). In addition, the bio-slurry exhibits good stability. Steam gasification of bio-slurry can produce hydrogen-rich gas, and the high gas yields (especially for H2 and CO) are obtained at around 900 °C. [ABSTRACT FROM AUTHOR]

This paper provides a new approach for using the by-products of bio-oil and bio-char, which are derived from the biomass gas station in rural China. Bio-slurry was prepared by blending bio-oil with different concentrations of bio-char (0-20 wt.%), and the production of hydrogen from steam gasification of bio-slurry was investigated. It is found that the bio-slurry fuels prepared from the carbonization products have better fuel properties including calorific value and stability in comparison to those prepared using fast pyrolysis products. The results demonstrate that the apparent viscosities of bio-slurry vary with bio-char contents (in the range of 0 to 20 wt.%) and temperature (from 7 o C to 50 o C). In addition, the bio-slurry exhibits good stability. Steam gasification of bio-slurry can produce hydrogen-rich gas, and the high gas yields (especially for H 2 and CO) are obtained at around 900 o C. [ABSTRACT FROM AUTHOR]

Energy is one of the basic needs modern civilizations. Fossil fuels presently are the major primary energy source. However, it contributes maximum to the climate change problem also. With suitable technology greenhouse gas emission may be reduced. Employing CO 2 capture process for energy efficient system using CO 2 neutral fuels is one possible solution in this context. In this paper a biomass based combined power plant with CO 2 capture has been proposed. Thermodynamic modelling for the detail process of this plant has been simulated by using ASPEN Plus ® . Results show that post- combustion CO 2 capture process has potential in CO 2 negative energy system. Artificial thermal efficiency is also calculated and its variation with carbon capture efficiency is studied. The degree of CO 2 capture has to be decided on the basis of overall performance of the plant specifically beyond certain value as CO 2 capture efficiency is quit flexible for a net-CO 2 negative emission plant. [ABSTRACT FROM AUTHOR]

Abstract: Solar gasification has the benefits of maximizing the yield of synthesis gas from gasification of biomass and other carbonaceous feed stock and storing solar energy in chemical form. The University of Minnesota has developed a 3kWth prototype solar gasification reactor in which biomass is converted to synthesis gas within a molten carbonate salt. The salt serves as a catalyst for gasification, ensures effective transfer of heat to the reactants, and provides thermal storage to ensure steady operation. This paper describes the reactor concept and provides an overview of the design process. [Copyright &y& Elsevier]