Experimental study of bottom feed updraft gasifier

The updraft biomass gasifiers currently available produce a gas with high tar content. For almost all downstream applications a substantial reduction of the tar concentration is required. The gravimetric tar concentration behavior in producer gas, obtained at a modified updraft fixed bed gasifier, was studied. The feedstock feeding system was modified respect to the traditional updraft gasification design in order to decrease the tar concentration in the producer gas; the material is feeding continuously through a conduit in the base of the reactor over the grate. The caloric power of the syngas obtained was slightly lower than the typical value for this type of reactor and the highest efficiency obtained for the woodchip gasification was 77%. The highest tar concentration obtained during the experiments was 1652.7 mg N m-3 during the first our of experiments, comparable with the smaller value reported for the updraft reactors, this value is reduced significantly after the stabilization of the gasification process in the reactor. The smaller value obtained was 21 mg N m-3. © 2013 Elsevier Ltd.

Análise de dificuldades técnicas e econômicas na inserção da cogeração pelas usinas sucroalcooleiras

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Kinetic study of the co-firing of bagasse-sludge blends

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Electricity, hot water and cold water production from biomass. Energetic and economical analysis of the compact system of cogeneration run with woodgas from a small downdraft gasifier

Wood gasification technologies to convert the biomass into fuel gas stand out. on the other hand, producing electrical energy from stationary engine is widely spread, and its application in rural communities where the electrical network doesn't exist is very required. The recovery of exhaust gases (engine) is a possibility that makes the system attractive when compared with the same components used to obtain individual heat such as electric power. This paper presents an energetic alternative to adapt a fixed bed gasifier with a compact cogeneration system in order to cover electrical and thermal demands in a rural area and showing an energy solution for small social communities using renewable fuels. Therefore, an energetic and economical analysis from a cogeneration system producing electric energy, hot and cold water, using wooden gas as fuel from a small-sized gasifier was calculated. The energy balance that includes the energy efficiency (electric generation as well as hot and cold water system; performance coefficient and the heat exchanger, among other items), was calculated. Considering the annual interest rates and the amortization periods, the costs of production of electrical energy, hot and cold water were calculated, taking into account the investment, the operation and the maintenance cost of the equipments. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.

Thermodynamic analysis and comparison of downdraft gasifiers integrated with gas turbine, spark and compression ignition engines for distributed power generation

The objective of the present article is to assess and compare the performance of electricity generation systems integrated with downdraft biomass gasifiers for distributed power generation. A model for estimating the electric power generation of internal combustion engines and gas turbines powered by syngas was developed. First, the model determines the syngas composition and the lower heating value; and second, these data are used to evaluate power generation in Otto, Diesel, and Brayton cycles. Four synthesis gas compositions were tested for gasification with: air; pure oxygen; 60% oxygen with 40% steam; and 60% air with 40% steam. The results show a maximum power ratio of 0.567 kWh/Nm(3) for the gas turbine system, 0.647 kWh/Nm(3) for the compression ignition engine, and 0.775 kWh/Nm(3) for the spark-ignition engine while running on synthesis gas which was produced using pure oxygen as gasification agent. When these three systems run on synthesis gas produced using atmospheric air as gasification agent, the maximum power ratios were 0.274 kWh/Nm(3) for the gas turbine system, 0.302 kWh/Nm(3) for CIE, and 0.282 kWh/Nm(3) for SIE. The relationship between power output and synthesis gas flow variations is presented as is the dependence of efficiency on compression ratios. Since the maximum attainable power ratio of CIE is higher than that of SIE for gasification with air, more research should be performed on utilization of synthesis gas in CIE. (C) 2014 Elsevier Ltd. All rights reserved.

The effect of power-ultrasound on the pretreatment of acidified aqueous solutions of banana flower-stalk: Structural, chemical and statistical analysis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)