scholarly journals Coal-Biomass Gasification in a Pressurized Fluidized Bed Gasifier

1998 ◽  
Author(s):  
W. de Jong ◽  
J. Andries ◽  
K. R. G. Hein
Keyword(s):  
Gas Turbine ◽  
Fluidized Bed ◽  
Process Development ◽  
Thermal Capacity ◽  
Process Conditions ◽  
Fuel Gas ◽  
Development Unit ◽  
State Behaviour ◽  
Fluidized Bed Gasifier ◽  
The Impact

In the framework of a multi-national European Joule project, experimental research and modeling concerning co-gasification of biomass and coal in a bubbling pressurized fluidized bed reactor is performed. The impact of fuel characteristics (biomass type, mixing ratio) and process conditions (pressure, temperature, gas residence time, air-fuel ratio and air-steam ratio) on the performance of the gasifier (carbon conversion, fuel gas composition, non-steady state behaviour) was studied experimentally and theoretically. Pelletized straw and miscanthus were used as biomass fuels. The process development unit has a maximum thermal capacity of 1.5 MW and was operated at pressures up to 10 bar and bed temperatures in the range of 650 °C–900 °C. The bed zone of the reactor is 2 m high with a diameter of 0.4 m and is followed by an adiabatic freeboard, approximately 4 m high with a diameter of 0.5 m. Time-averaged as well as time-dependent characteristics of the fuel gas were determined experimentally. The results will be compared with the gas turbine requirements provided by a gas turbine manufacturer, one of the partners in the project. The evaluation of the results will ultimately be used to implement and test an adequate control strategy for the pressurized fluidized bed gasifier integrated with a gas turbine combustion chamber.

Biomass-Based, Small-Scale, Distributed Generation of Electricity and Heat Using Integrated Gas Turbine-Fuel Cell Systems

2000 ◽  
Author(s):  
B. J. P. Buhre ◽  
J. Andries
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
High Efficiency ◽  
Process Development ◽  
Small Scale ◽  
Fuel Gas ◽  
Gas Cleaning ◽  
Development Unit ◽  
System Designs ◽  
Process Development Unit

The use of a biomass gasifier that drives a gas turbine integrated with a fuel cell, is a potentially very attractive way to generate electricity and heat with a high efficiency and very low emissions. The application of catalytic combustion systems can decrease the emissions even further. A number of technical and non-technical developments during the last 5 years have significantly enhanced the opportunities for small-scale, distributed power generation, especially for systems based on biomass fuels. These developments are: the liberalisation of the energy market, the growing needs for electricity and heat in developing countries, the increasing demand for ‘green’ or ‘sustainable’ electricity, the near-commercial availability of maintenance-low microturbine generator packages and developments in the field of high temperature fuel cells. Preliminary system studies have shown that the integration of the different subsystems needs careful evaluation in order to realise the expected high efficiencies. To enable the assessment of the technical feasibility of potentially attractive system designs, adequate, experimentally validated knowledge with regard to biomass gasification, pressurised combustion of the fuel gas and the gas cleaning steps is required. Possible system designs based on a combination of electrochemical and thermochemical fuel conversion steps are examined and analysed with regard to efficiency, emission and costs. A system design for application on commercial scale based on present day technology will be considered. At Delft University of Technology, a biomass gasifier has been set up and a conceptual design for a pilot system, to be tested in the slipstream of the Delft 1.5 MWth process development unit, will be presented. The process development unit is described in more detail in [Hoppesteyn, et. al., 1998] and [de Jong et. al., 1998]. In this study, it has been attempted to integrate an SOFC with an existing micro gas turbine that has not especially been adjusted for the integration with the SOFC.

Gas Turbine Combined Cycle With CO2-Capture Using Auto-Thermal Reforming of Natural Gas

2000 ◽  
Author(s):  
Thormod Andersen ◽  
Hanne M. Kvamsdal ◽  
Olav Bolland
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Process Integration ◽  
Combined Cycle ◽  
Co2 Removal ◽  
Gas Turbine Combustor ◽  
Chemical Absorption ◽  
Fuel Gas ◽  
The Impact ◽  
Water Gas

A concept for capturing and sequestering CO2 from a natural gas fired combined cycle power plant is presented. The present approach is to decarbonise the fuel prior to combustion by reforming natural gas, producing a hydrogen-rich fuel. The reforming process consists of an air-blown pressurised auto-thermal reformer that produces a gas containing H2, CO and a small fraction of CH4 as combustible components. The gas is then led through a water gas shift reactor, where the equilibrium of CO and H2O is shifted towards CO2 and H2. The CO2 is then captured from the resulting gas by chemical absorption. The gas turbine of this system is then fed with a fuel gas containing approximately 50% H2. In order to achieve acceptable level of fuel-to-electricity conversion efficiency, this kind of process is attractive because of the possibility of process integration between the combined cycle and the reforming process. A comparison is made between a “standard” combined cycle and the current process with CO2-removal. This study also comprise an investigation of using a lower pressure level in the reforming section than in the gas turbine combustor and the impact of reduced steam/carbon ratio in the main reformer. The impact on gas turbine operation because of massive air bleed and the use of a hydrogen rich fuel is discussed.

scholarly journals Effect of Pressure on Second-Generation Pressurized Fluidized Bed Combustion Plants

1994 ◽  
Vol 116 (2) ◽  
pp. 345-351 ◽  
Author(s):  
A. Robertson ◽  
D. Bonk
Keyword(s):  
Gas Turbine ◽  
Fluidized Bed ◽  
Coal Gasification ◽  
Second Generation ◽  
Electrical Power ◽  
Fluidized Bed Combustion ◽  
Fuel Gas ◽  
Combustion Gas ◽  
New Type ◽  
Pressurized Fluidized Bed Combustion

In the search for a more efficient, less costly, and more environmentally responsible method for generating electrical power from coal, research and development has turned to advanced pressurized fluidized bed combustion (PFBC) and coal gasification technologies. A logical extension of this work is the second-generation PFBC plant, which incorporates key components of each of these technologies. In this new type of plant, coal is devolatilized/carbonized before it is injected into the PFB combustor bed, and the low-Btu fuel gas produced by this process is burned in a gas turbine topping combustor. By integrating coal carbonization with PFB coal/char combustion, gas turbine inlet temperatures higher than 1149°C (2100°F) can be achieved. The carbonizer, PFB combustor, and particulate-capturing hot gas cleanup systems operate at 871°C (1600°F), permitting sulfur capture by time-based sorbents and minimizing the release of coal contaminants to the gases. This paper presents the performance and economics of this new type of plant and provides a brief overview of the pilot plant test programs being conducted to support its development.

scholarly journals A preliminary environmental analysis for a sustainable pyrolysis process of Acacia tortilis encroacher bush.

2021 ◽  
Author(s):  
Gratitude Charis ◽  
Edison Muzenda ◽  
Gwiranai Danha
Keyword(s):  
Mass Balance ◽  
Process Development ◽  
Assessment Method ◽  
Raw Material ◽  
General Effect ◽  
Fuel Gas ◽  
Bio Oil ◽  
Critical Materials ◽  
The Impact ◽  
Shortcut Method

Abstract A shortcut method of environmental assessment was applied procedurally to an Acacia Tortillis pyrolysis project which is in early stages of process development. The method uses mass balance data from the process simulation, which is done in ChemCAD. The ChemCAD model was developed using characterization data for raw biomass and the product bio-oil and data from literature. The shortcut assessment method started off by scoring the impact of inputs and outputs as high (A=1), medium (B= 0.3) and very low (C= 0) under impact categories such as raw material availability, use of critical materials, chronic toxicity, global warming potential, odour and eutrophication potential. An aggregated metric called the general effect index (GEI) was then calculated using this data and mass indices derived from mass balance. The GEI was calculated for inputs, outputs and the overall process. It fell within the scale of 0-1, with values below 0.5 indicating a low environmental impact, while those above that threshold indicated high impact. A GEI of 0 for the inputs reflected on the renewability of biomass and neutral impact of nitrogen and air. A GEI of 0.370 for the outputs showed they do have a significant effect on the environment and organisms, though overall, the process is relatively benign. The impact could be further reduced by utilizing the fuel gas waste stream which has a high methane content. The results obtained generally tally with other literary findings on biomass pyrolysis.

Catalytic decomposition of ammonia in fuel gas produced in pilot-scale pressurized fluidized-bed gasifier

1995 ◽  
Vol 45 (3) ◽  
pp. 221-236 ◽  
Author(s):  
Wahab Mojtahedi ◽  
Matti Ylitalo ◽  
Teuvo Maunula ◽  
Javad Abbasian
Keyword(s):  
Fluidized Bed ◽  
Catalytic Decomposition ◽  
Pilot Scale ◽  
Fuel Gas ◽  
Fluidized Bed Gasifier
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