Hot syngas cleanup for pilot two-stage fluidized bed steam-oxygen biomass gasification plant.

Biomass gasification as a renewable energy technology has been a widely explored research and development area. The efficient and economic removal of harmful components, particularly tars, in raw syngas from the biomass gasifier is still a major challenge. In this study, a novel two-stage fluidized bed pilot-scale gasifier has been developed to enhance the steam-oxygen biomass gasification to generate low-tar syngas; while, a prototype hot syngas cleanup system has been designed, built and tested to further reduce the tar content and purify the syngas from the biomass gasifier for downstream applications.

Simulation of heavy metals behaviour during Co-processing of fly ash from municipal solid waste incineration with cement raw meal in a rotary kiln.

Fly ash produced from incineration of municipal solid wastes (MSW) contains heavy metals, such as Cd and Pb, that make this material difficult to manage and dispose of safely. Because the composition of fly ash is similar to cement raw meal, partial replacement of raw meal with fly ash may be a feasible way to reduce the health and environmental hazards of the ash, provided that the heavy metals can be effectively stabilized in the solid phase. This research employs proprietary thermochemical software to simulate the thermodynamic behavior and single-step fixation of Cd and Pb in industrial cement kilns.

Effects of temperature and particle size on biomass torrefaction in a slot-rectangular spouted bed reactor.

Sawdust particles of different sizes (0.25-0.5, 0.

Simulation of biomass-steam gasification in fluidized bed reactors: Model setup, comparisons and preliminary predictions.

A user-defined solver integrating the solid-gas surface reactions and the multi-phase particle-in-cell (MP-PIC) approach is built based on the OpenFOAM software. The solver is tested against experiments. Then, biomass-steam gasification in a dual fluidized bed (DFB) gasifier is preliminarily predicted.

Co-gasification of biosolids with biomass: Thermogravimetric analysis and pilot scale study in a bubbling fluidized bed reactor.

This work studied the feasibility of co-gasification of biosolids with biomass as a means of disposal with energy recovery. The kinetics study at 800°C showed that biomass, such as switchgrass, could catalyze the reactions because switchgrass ash contained a high proportion of potassium, an excellent catalyst for gasification. However, biosolids could also inhibit gasification due to interaction between biomass alkali/alkaline earth metals and biosolids clay minerals.

Comparison between elderly inpatient fallers with and without dementia.

Introduction: This study aimed to examine the various factors associated with inpatient falls among patients with and without dementia in a hospital setting.

Methods: This was a retrospective one-year study using data collected from Singapore General Hospital's electronic reporting system for inpatient falls.

Results: In the study period, 298 patients aged ≥ 65 years fell during their hospital stay.

SO2-catalyzed steam pretreatment enhances the strength and stability of softwood pellets.

Densification can partially resolve the logistical challenges encountered when large volumes of biomass are required for bioconversion processes to benefit from economies-of-scale. Despite the higher bulk density of pellets, their lower mechanical strength and sensitivity to moisture are still recurring issues hindering long term transportation and storage. In this study, we have evaluated the potential benefits of SO(2)-catalyzed steam treatment to achieve both the needed size reduction prior to pelletization while improving the stability of the produced pellets.

Drying characteristics and equilibrium moisture content of steam-treated Douglas fir (Pseudotsuga menziesii L.).

Douglas fir (Pseudotsuga menziesii L.) particles were exposed to high pressure saturated steam (200 and 220 °C for 5 and 10 min) to improve the durability and hydrophobicity of pellets produced from them. Depending on treatment severity, the moisture content of the particles increased from 10% to 36% (wet basis).

Effects of headspace and oxygen level on off-gas emissions from wood pellets in storage.

Few papers have been published in the open literature on the emissions from biomass fuels, including wood pellets, during the storage and transportation and their potential health impacts. The purpose of this study is to provide data on the concentrations, emission factors, and emission rate factors of CO(2), CO, and CH(4) from wood pellets stored with different headspace to container volume ratios with different initial oxygen levels, in order to develop methods to reduce the toxic off-gas emissions and accumulation in storage spaces. Metal containers (45 l, 305 mm diameter by 610 mm long) were used to study the effect of headspace and oxygen levels on the off-gas emissions from wood pellets.

Rate and peak concentrations of off-gas emissions in stored wood pellets--sensitivities to temperature, relative humidity, and headspace volume.

Wood pellets emit CO, CO(2), CH(4), and other volatiles during storage. Increased concentration of these gases in a sealed storage causes depletion of concentration of oxygen. The storage environment becomes toxic to those who operate in and around these storages.

Predictors of length of stay between the young and aged in hospitalized community-acquired pneumonia patients.

Aim: To determine the factors that may prolong the length of stay (LOS) for older patients hospitalized for community-acquired pneumonia (CAP) and also to see if they are applicable to the younger patients.

Methods: A retrospective case record review was conducted of all adult patients who were discharged from the general medical service or the geriatric medicine service of an acute care hospital over 6 months.

Results: During the study period, 393 patients were discharged with the diagnosis of pneumonia.

Characterization and kinetics study of off-gas emissions from stored wood pellets.

The full potential health impact from the emissions of biomass fuels, including wood pellets, during storage and transportation has not been documented in the open literature. The purpose of this study is to provide data on the concentration of CO(2), CO and CH(4) from wood pellets stored in sealed vessels and to develop a kinetic model for predicting the transient emission rate factors at different storage temperatures. Five 45-l metal containers (305 mm diameter by 610 mm long) equipped with heating and temperature control devices were used to study the temperature effect on the off-gas emissions from wood pellets.

Sequential capture of CO2 and SO2 in a pressurized TGA simulating FBC conditions.

Four FBC-based processes were investigated as possible means of sequentially capturing SO2 and CO2. Sorbent performance is the key to their technical feasibility. Two sorbents (a limestone and a dolomite) were tested in a pressurized thermogravimetric analyzer (PTGA).

Characterization of the enhancement effect of Na2CO3 on the sulfur capture capacity of limestones.

It has been known for a long time that certain additives (e.g., NaCl, CaCl2, Na2CO3, Fe2O3) can increase the sulfur dioxide capture-capacity of limestones.