H. Seifert

Simultaneous Removal of Mercury, PCDD/F, and Fine Particles from Flue Gas

A multifunctional scrubber (MFS) has been developed to reduce the complexity of flue gas cleaning plants. The MFS integrates an oxidizing scrubber equipped with a dioxin-absorbing tower packing material and a space charge electrostatic precipitator. All these processes have been previously developed at Forschungszentrum Karlsruhe. In the described multifunctional scrubber, mercury, sulfur dioxide, hydrogen chloride, polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), and submicrometer particles are removed simultaneously. A MFS pilot plant with a flue gas volume flow of 250 m(3)/h has been installed in a slipstream of a waste incineration pilot plant. Pilot scale testing was performed to measure mercury, particles, and PCDD/F in the raw and clean gas. After optimization of the process these three flue gas components were separated from the flue gas in the range 87-97%.

Collection of Fine Particles by Novel Wet Electrostatic Precipitator

A novel wet electrostatic precipitator is designed for control of fine aerosol from humid effluent gases. It operates on the principle of unipolar particle charging in a DC corona discharge in a high velocity (> 20 m/s) ionizing stage and aerosol precipitation in the low velocity (< 3 m/s) collection stage under the field of particle own space charge. The high gas velocity in the ionizing section diminishes the corona suppression at high particle number concentrations of H2SO4 and HCl aerosol.

Characterisation of combustion behaviour of refuse derived fuel

AbstractThe combustion process of heterogeneous solid fuels like refuse derived fuel is investigated in a fixed bed reactor. Characteristic parameters are derived for the quantitative description of solid fuel combustion. The experimental setup of the fixed bed reactor KLEAA at Forschungszentrum Karlsruhe with a volume of ∼10 L, allows for using technical solid fuel fractions with a maximum particle size of ∼80 mm. It is equipped with gas species sampling train, local temperature measurement and mass control. Characteristic parameters, such as reaction front velocity (RFV), fuel ignition rate (FIR), fuel consumption rate (FCR) are derived from experimental data to quantify the combustion behaviour of different fuels as a function of fuel specification and operational conditions. The influence of fuel moisture content and primary air flowrate on the combustion rate of wood based fuels is investigated in detail. The RFV of different waste and biomass based solid fuels is compared. Based on the characteristi...

The potential of a sustainable municipal waste management system for Santiago de Chile, including energy production from waste

BackgroundDue to a rapid urbanization process in the Metropolitan Region of Santiago de Chile (MRS), the amount of municipal solid waste (MSW) generated has increased considerably within the last years. MSW should be managed properly in order to achieve sustainable development. The purpose of this study is to analyze MSW management in MRS on the basis of three different explorative scenarios for the year 2030.MethodsThe Integrative Sustainability Concept of the Helmholtz Association provided a conceptual framework for the study and was used to evaluate the scenarios. One important topic within the field of management of MSW in the year 2030 will be the contribution of waste treatment technologies to energy production, e.g., by the use of landfill gas and by separated collection of biowaste followed by anaerobic treatment.ResultsThe largest sustainability deficits in the scenarios are the small proportion of MSW being pre-treated before final disposal and the greenhouse gas (GHG) emissions associated with MSW disposal. MSW management technologies taken into consideration were mechanical biological treatment, energy recovery from MSW in anaerobic digestion plants with biogas production, the production of refuse-derived fuel and its use as a secondary fuel, as well as electricity generation from landfill gas. Energy generation from MSW in 2030 will be about 6% of electricity consumption in 2010.ConclusionsThe three scenarios show some sustainability deficits. Even so, there are some improvements such as the reduction of GHG emissions and - even though marginal - energy supply for MRS from renewable energy sources.

Fine particle generation, evolution and control by small biomass combustion

Purpose – The aim of the paper is to present the results of investigations of fine particle generation by small biomass combustion and the possibility of reducing the emissions by electrostatic precipitation.Design/methodology/approach – The grains, wood‐logs, wood‐, mixed‐ and straw‐pellets were combusted in two stoves and two boilers. The set‐ups were operated according to DIN‐4702. Particle number concentration in the gas flow was measured by Scanning Mobility Particle Sizer and particle mass concentration was measured according to the Guidelines VDI‐2066 upstream and downstream a novel space charge electrostatic precipitator (ESP). The ESP consists of an ioniser and a grounded brush inside of a tube form grounded collector electrode.Findings – The ESP ensures stable operation at gas temperatures up to 350°C. The use of sharp‐points high voltage electrode ensures effective particle charging at high particle number concentrations. The combustion of wood‐pellets is characterized by lower particle mass co...