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Analytical methods for electron
beam flue gas treatment
technology
Janusz Licki1, Andrzej G. Chmielewski2,, 1 National Centre for Nuclear Research, Sołtana 7, 05-400 Otwock-Świerk, Poland
2 Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland
New trends in application of modern electron beam generation
in air pollution, Warsaw 15 January 2014
The results of parametric tests of the EBFGT process indicate that SO2 and NOx removal efficiency
depends mainly on the following process parameters: absorbed dose, gas temperature and
humidity at process vessel, ammonia stoichiometry and inlet NOx and SO2 concentration. Proper
selection of process parameters ensures high SO2 and NOx removal efficiency. The control and
monitoring system of industrial plant is extremely important for achieving a successful plant
operation. The computerized process control and monitoring system (CPCMS) is designed to
perform continuous monitoring of the process parameters and automatic (computer-based) control
of the whole installation operation. The experience gained upon execution of the CPCMS project of
Polish industrial plant at EPS Pomorzany and during its long-term operation was used during
preparation of this project.
Parameters Unit Chengdu TPP
China
Hangzhou TPP
China
Pomorzany EPS
Poland
Nominal flue gas flow rate Nm3/h 300 000 305 400 270 000
Inlet flue gas temperature C 150 145 140
Inlet SO2 concentration ppmv 1800 970 700
Inlet NOx concentration ppmv 400 200 300
SO2 removal efficiency % 80 85 95
NOx removal efficiency % 18 55 70
Electron beam parameters 800 keV
2x400mA
800 keV
2x400mA
700 keV
4x375mA
Table 1. Main parameters of industrial e-beam plants.
In each of the above steps the monitoring system and control system realize specific tasks. The
actual values of process parameters, determined by monitoring system, are employed for
technological modification realized by control system. The information from monitoring system can
be used for feedback and feedforward control of the plant operation to enhance the efficiency of e-
beam process. Digital control system is used to store and evaluation of measured data and to
assist plant operator in his analysis and optimization of plant operation. The main function of
CPCMS is ensuring plant run with optimal SO2 and NOx removal efficiencies.
Fig. 1. Schematic diagram of an EBFGT process.
System Description
For achieving successful plant operation the following systems were designed:
monitoring system,
control system,
ecological monitoring system.
Monitoring System
The general tasks of the monitoring system are:
– continuous, reliable and precise measurements parameters of flue gases, electron beams and reagents adding to the flue gas having direct influence on the efficiency of SO2 and NOx removal as well as on the operation of the whole industrial plant,
– acquisition and visualization of process parameters. Visualization of flow charts on high-resolution monitor including visualization of regular updated measurement data,
– storage and evaluation of process parameters, media consumption and pollutants emission from plant. Data acquisition and processing should be performed automatically and the obligatory report from plant emission should be sent directly to the regulatory authority for checking and acceptance. Preparation of reports on request.
The presentation of all data should take place in the control room of the plant onhigh-resolution monitors and on videoscreen. Further presentation takes place inthe operator station for boilers and in the ecological department of TPS.
The reliable and accurate measurements of flue gases composition at the essential points of e-beam installation are indispensable for monitoring and controlling of the EBFGT process. In the selection of measuring equipment it is necessary to consider the specifics of the e-beam process.
Flue gases
parameter
Measuring
method
Measuring
device
Special
requirements
Volumetric flow
rate
in-situ annubar (multiple-point Pitot tube) or
ultrasonic flow meter
correction for flue gases
temperature, pressure and humidity;
regular blowback of the probe
dust
concentration
in-situ double-pass transmissometer for high
dust concentration (at plant inlet) and
back scatter device for low-level
concentration (at plant outlet)
SO2
concentration
extractive pulsed U.V. fluorescence analyzer or
NDUV analyzer or NDIR analyzer
application of multi-layer detector
or gas filters correlation technique
NO/NOx
concentration
extractive chemiluminescence NO-NO2-NOx
analyzer or NDIR analyzer with
NO2→NO converter
H2O
concentration
in-situ diode laser spectrometer in the IR
spectrum
application of heated device to avoid
water vapor condensation on lenses
NH3
concentration
in-situ diode laser spectrometer in the IR
spectrum
application of heated device to avoid
water vapor condensation on lenses
Table 2. Analytical method recommended for application in the industrial e-beam plant.
Extractive system
Schematic representation of the extractive continuous emission monitoring system.
Particular features and user benefits of
Ultramat 23 include:
•high selectivity and measuring accuracy
because of the single beam design with triple
layer detector,
•highest long-term stability without the need of
expensive calibration gases by means of
autocalibration using ambient air. A check with
costly test gases is required only once every
year,
•approval certificate for the required lowest
measuring ranges. Further more the analyzer
does comply with the requirements of QAL1,
•cost efficient determination of all 4 gas
components using only one analyzer.
The sample probe is installed in the duct. Gas
sample is filtered by ceramic filter with 2 m pore
size. Sample probe and ceramic filter can be
heated up to 180ºC (SP2000H).
It is possible to connect a blowback system for
periodical cleaning of ceramic filter with a reverse
flow of compressed air as well as introduce the
calibration gas at the probe.
Flow diagram of extractive system
for determination of SO2, O2 and
NOx=NO+NO2 concentrations in
the flue gas at plant inlet
Flow diagram of extractive
system for determination of SO2,
O2 and NOx=NO+NO2
concentrations in the flue gas at
plant outlet.
In-situ systems
Volumetric flow rate measuring system
The D-FL 100 measuring system, offered by Durag (Germany), works according to the principle of mechanical
effect. The probe has two separate chambers with 4-8 openings, between which a pressure difference, caused by
the gas flow in the duct, builds up. The differential pressure resulting at the probe is proportional to the square of
the gas speed. Due to the probes special shape, a highest possible differential pressure is produces whereby the
linearity of the measuring signal is guaranteed.
Dust concentration measuring systems
Measuring device for low dust concentrations D-R 300-40 from Durag
For measurement of very low-level dust concentrations are used meters operated according to
the scattered light method. The modulated light from a halogen lamp illuminates the dust particles
in the exhaust duct. The scattered light reflected from these particles is measured and assessed.
Such device should be installed at plant outlet (after ESP).
An overall view of LDS 6 in-situ diode laser gas analyzer from Siemens
For measurement of humidity and NH3 concentration in the flue gas can be used in-situ gas
analyzer LDS 6. It is the diode laser spectrometer in the IR spectrum which can measure up to
three measuring points simultaneously. The light source is a diode laser whose wavelength is
matched to an absorption line of the gas to be measured. LDS 6 consists of a central unit and up to
three pairs of cross duct sensors in a transmitter/receiver configuration. The central unit is
separated from the sensors by using fibre optics.
Control System
The general tasks of the control system are:
on-line adjustment of process parameters to achieve the optimal SO2 and NOx removal efficiency,
supervision and control of process parameters under normal, transient, alarm and breakdown condition,
signalling and registering of the alarm states. All cases of installation malfunctioning must be immediately reported to the operator with possible suggestion concerning recommended course of action.
Digital control system is used primarily for real time processing of large amount of measured data and to assist plant operator in his analysis and optimization of plant operation. Effective control of the plant can improve the removal efficiencies of SO2 and NOx from flue gas. The final control objects are outlet concentration of SO2, NOx and NH3 slip. The control objects of the system are: amount of sprayed water at spray cooler to control flue gas temperature and humidity, amount of NH3 addition to control ammonia stoichiometry and electron beams current to control irradiation dose. The control system of the plant also interfaces directly with the boiler control system so that boiler information can be displayed directly in the plant control room and used to help make operational decisions.
Effect of moisture on NOx and SO2
removal efficiencies
Effect of gas temperature on NOx and SO2
removal efficiencies
The schematic diagram of the spray cooler
with measuring and control devices
Scheme of the monitoring and control system of the industrial plant
Flow diagram of the Ecological Monitoring System
Ecological Monitoring System
The industrial EBFGT plant is designed for purification of flue gas emitted from coal-fired boiler. The gas leaving
the plant should met the environmental standards given by legislation, e.g. EU Directive 2001/80/EC. Its
compatibility with the requirements should be documented in the form of the obligatory reports from industrial plant
operation. Such report contains information about emission of certain pollutants into the air during normal plant
operation as well as the information about malfunction plant operation.
Computer Control System configuration
Control room of EPS Pomorzany
New trends in application of modern electron beam generation
in air pollution, Warsaw 15 January 2014
Thank you for your
attention!
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