BIOS - Bioenergy
  YOUR PARTNER FOR ENERGY FROM BIOMASS AND ENERGY EFFICIENCY  
 

Measurements

Brochure

Overview

BIOS BIOENERGIESYSTEME GmbH has an extensive range of equipment for the performance of field tests at combustion units, gasification units and biogas units at its disposal. On the one hand conventional gas analysers and particle measurement techniques and on the other hand specially designed innovative methods and devices for fly ash, aerosol and deposit sampling as well as for hot gas measurements (measurement and sampling in the furnace at temperatures up to 1,200°C) are available.

Due to the modular design of the data loggers it is possible to collect measurement data at several distant locations in a plant as well as visualise and store them on a central computer. Therefore, a high flexibility concerning the solution of different measurement problems can be gained. For data evaluation in-house developed software is available.

Measurement: Processes:
Conventional flue gas measurements at combustion units: O2, CO, CO2, NOx, NO2, TOC, dust, HCl, SOx, NH3, gaseous heavy metals conventional
continuous methods

conventional
discontinuous methods
Conventional flue gas measurements at biogas plants:
CH4, CO, CO2, H2S, NH3, O2
conventional
continuous methods
Product gas measurements at biomass gasification units:
CO, CO2, H2, CH4, CxHy, tars (including tar analyses)
conventional
continuous methods

conventional
discontinuous methods
Measurement of the flue gas temperatures in furnaces and boilers of biomass combustion units using suction pyrometers conventional
continuous methods
Measurements to determine mass and energy balances of combustion processes conventional
continuous methods
conventional
discontinuous methods
conventional
particle measurement technique
Determination of the particle size distribution and concentration of aerosols and fly ashes in the flue gas conventional
particle measurement technique
innovative methods
electric low-pressure impactor
Ash, fly ash, and aerosol sampling in biomass combustion processes for subsequent wet chemical analyses and analyses by electron microscopy particle sampling and analyses
Hot gas sampling of particles in the furnace high temperature particle sampling
Deposit sampling and analyses in biomass furnaces and boilers deposit sampling

Conventional analysers, sensors and methods

Continuous methods

Parameter Method Device
O2 Paramagnetic Rosemount NGA 2000
CO/CO2 NDIR Rosemount NGA 2000
TOC Flame Ionisation Detection Rosemount NGA 2000
TOC Flame Ionisation Detection Bernath Atomic 3005
NOx/NO2 Chemiluminescence ECO Physics CLD 700 EL ht
O2, CO, NO Electrochemical Testo 350
H2 Heat conductivity Rosemount NGA 2000
CH4, CO2 Infra-red technique GA2000+ Landfill gas analyser
CO, H2S, NH3, O2 Electrochemical GA2000+ Landfill gas analyser
CO, NO, NO2, N2O, HCN, HCl, SO2, NH3, CH4, several hydrocarbons FT-IR Ansyco GASMET DX-4000
Pressure Two wire technique pressure gauge Contrans P AMD 230
Differential pressure Two wire technique pressure gauge Contrans P ASK 800
Temperature Resistance, thermal stress  
Gas humidity Thermo-Hygrometer Jumo B90.7023
Gas velocity Prandtl-tubes, calorimetric  

Discontinuous methods

Parameter Method
SOx- and HCl- concentration in the flue gas Method according to VDI 3480; gas sampling with heated probe, dust removal and collection of acid compounds in distilled water with H2O2, NaOH. Detection by HPLC
NH3-concentration in the flue gas Gas sampling with heated probe, dust removal and collection in H2SO4. Detection according to Kjeldahl.
Hg-concentration in the
flue gas
Gas sampling with heated probe, dust removal and collection of Hg in cooled H2SO4 and diluted nitric acid. Detection by HGAAS or ICP-MS.
Heavy metal vapours in
the flue gas
Gas sampling with heated probe, dust removal and collection of heavy metals in cooled diluted nitric acid. Detection by absorption spectrometry (FAAS, ICP-OES or GFAAS) or mass spectrometry (ICP-MS).
Tar sampling and tar analyses Gravimetric method according to the „Tar Protocol“. Adsorption of tars in propanol at -20°C; evaporation of the solvent in a vacuum dryer and subsequent gravimetric determination of the tar content as well as tar analyses regarding C, H and N.
Gas sampling tube Discontinuous product gas sampling in a sampling tube and subsequent analyses by means of gas chromatography and mass spectrometry (GC-MS) regarding CO, CO2, H2, CH4, O2 and N2.

Particle measurement techniques

Total dust concentration in flue gases

Method: Gravimetric method according to VDI 2066.

Device: Ströhlein ST E 4

Principle:
For a certain period a slipstream of the flue gas is sucked through a quartz wool filter, where the dust particles are precipitated. The dust concentration in the flue gas is calculated by the mass change of the filter divided by the flue gas volume sucked through the filter. To achieve representative sampling, the slip stream must be taken with the same velocity as the flue gas has at the sampling point (isokinetic sampling).

Particle size distribution and concentration of aerosols in the flue gas

(discontinuous method)

Method: Low-pressure cascade impactor

Devices: Hauke LPI30, cut diameters: 8/4/2/1/0.5/0.25/ 0.125/0.0625 µm
Dekati DGI, cut diameters: 2.5/1/0.5/0.2 µm

Principle:
A slip stream is isokinetically sampled from the flue gas channel and sucked through the impactor. The impactor consists of several stages. In each stage the flue gas changes its flow direction and particles which are too big to follow the streamlines of the flue gas, are precipitated.

particle separation in the impactor
scheme of one impactor stage
assembled cascade impactor
Particle size distribution and concentration of aerosols in the flue gas

(continuous method)

Method: Electrical low-pressure cascade impactor

Device: Dekati, 10lpm

Principle:
At the ELPI inlet particles are charged and then pass several impactor stages. As soon as a particle is separated from the flue gas, it looses its electrical charge. The resulting current is measured for each impactor stage and from these data, the particle size distribution is determined (as a number size distribution).
Therefore, the ELPI provides the possibility of quasi-continuously detecting the particle size distribution and concentration of aerosols and fly ashes in the flue gas within a size range between 0.03 and 8.97 mm in intervals down to 1 second. The ELPI is especially applicable for basic research concerning influencing parameters on aerosol (fine particle) formation in combustion plants as well as for the determination of separation efficiencies of fine particle precipitation devices.

Scheme of the ELPI
Deposit sampling and analyses

Method: Sampling with an air cooled deposit probe and subsequent analyses by SEM/EDX

Device: in-house development

Principle:

  • A deposit probe consists of an air cooled tube at which a sampling ring is mounted.
  • The deposit probe is inserted in the flue gas flow inside the furnace for a certain period.
  • The surface temperature of the sampling ring is controlled by the cooling air. Thereby it is possible to simulate the surface of a boiler tube.
  • The sampling ring is weighed before and after exposure to the flue gas and the ash deposit build-up on the ring is determined in g/m2/h.
  • Fly ash and aerosol deposits, which have been formed on the sampling ring, are afterwards analysed concerning their structure and chemical composition by using electron microscopy (SEM/EDX). These results represent a basis for the definition of guidelines concerning the melting behaviour of deposits and corrosion risks.
  • By these measures an evaluation of the risk for deposit build up during the combustion of a certain fuel at certain boiler tube surface temperatures is possible.
Scheme of the deposit probe (click images to zoom)
Deposit probe in operation
Sampling ring with deposit

Innovative methods

High-temperature particle sampling

To facilitate particle sampling for subsequent analyses by wet chemical measures and electron microscopy even from a high-temperature environment (e.g.: from the furnace), a special high-temperature low-pressure impactor has been developed in cooperation with the Institute for Process and Particle Engineering, Graz University of Technology. This device can be applied for in-situ particle sampling at temperatures up to 1,100°C

High temperature impactor in operation
High-temperature impactor immediately after sampling
Scheme of the High-temperature impactor

Particle sampling for subsequent analyses by wet chemical measures and electron microscopy

As an additional option the fly ash sampled with the total dust sampling equipment according to VDI 2066 as well as aerosol samples taken with the conventional low-pressure impactor can also be analysed concerning their chemical composition by wet chemical methods.

Furthermore, in co-operation with the Institute for Process and Particle Engineering, Graz University of Technology, and the Research Institute for Electron Microscopy, Graz University of Technology, BIOS BIOENERGIESYSTEME GmbH has developed special particle sampling methods, which facilitate analyses of single particles concerning their shape, structure and chemical composition by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDX).

SEM-image of a coarse fly ash particle sampled during beech combustion
SEM-image of aerosols sampled during bark combustion
SEM-image and element mapping of aerosols sampled with the High-temperature impactor in the hot flue gas at superheater inlet of a waste fired combustion plant (higher colour intensities indicate higher element concentration levels)