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!