Wednesday, June 24, 2015

Turbulence, Residence Time and Temperature are inbuilt in the plant design

No.    Parameter    Standards, Guideline, Criteria and Procedure
1    Basic Plant Design    An approved plant must have four distinct sections that demonstrate three principles of
Turbulence, Residence Time and Temperature are inbuilt in the plant design .The
regulated sections may include but not limited to:

Overall plant layout. Feed chamber/ charging
Primary Combustion Chamber. Secondary Combustion Chamber. Particulate Scrubbers
Acid Gas Scrubbers The stack/ chimney.
2    Feeding And Charging    Controlled hygienic, mechanical or automatic feeding methods have to be used which
will not influence the air temperature in the primary and secondary chambers of the
incinerator negatively.

No waste is to be fed into the incinerator:

1.    Until the minimum temperatures have been reached.

2.    If the minimum combustion temperatures are not maintained.
3.    Whenever the previous charge has not been completely combusted in the case of batch feeding.

4.    Until such time as the addition of more waste will not cause the design parameters of the incinerator to be exceeded.
3    Primary  Combustion
Chamber    The primary combustion chamber must:

1.    Be accepted as the primary combustion zone.
2.    Be equipped with a burner/s burning gas/fuel or low sulphur liquid fuels.
Other combustion methods will be judged on merits.

3.    Ensure primary air supply is controlled efficiently

4.    Ensure minimum exit temperature is not less than 850oC
4    Secondary
Combustion Chamber
(Afterburner).    The secondary combustion chamber must:

1.    Be accepted as secondary combustion zone.
2.    Be fitted with secondary burner/s burning gas or low sulphur liquid fuel or any suitable fuel.

3.    Ensure secondary air supply is controlled efficiently.

4.    Ensure flame contact with all gases is achieved.

5.    Ensure residence time is not less than two (2) seconds.
6.    Ensure the gas temperature as measured against the inside wall in the secondary chamber & not in the flame zone, is not less than 1100oC.

7.    Ensure the oxygen content of the emitted gases is not less than 11%.
8.    Ensure both primary and the combustion temperatures are maintained until all waste has been completely combusted
5    Particulate Removers    A mechanical particulate collector must be incorporated after secondary combustion
chamber for removal of particulate pollutants entrained in the flue gas stream. The
particulate collectors may include any of the following or a combination thereof:




22


Cyclone separator Electrostatic precipitators Fabric filters
6    Chimney / Stack    1.    The chimney should have a minimum height of 10 meters above ground level
and clear the highest point of the building by not less than 3 meters for all
roofs. The topography and height of adjacent buildings within 50 meters radius should be taken into account.

2.    If possible the chimney should be visible to the operator from the feeding area.
3.    The addition of dilution air after combustion in order to achieve the
requirement of these guidelines is unacceptable.

4.    The minimum exit velocity should be 10 m/s and at least twice the surrounding wind speed (Efflux velocity = wind speed x 2) whichever is higher to ensure no down washing of exiting gases.

5.    Point for the measurement of emissions shall be provided.
7    Instrumentation    Instrument for determining the inside wall temperature and not burner flame
temperature must be provided for both primary and secondary chambers.

2.    An audible and visible alarm must be installed to warn the operator when the secondary temperature drops to below the required temperature.

3.    In addition to the above the following instruments may also be required.

A carbon monoxide and/or oxygen meter/recorder A smoke density meter/recorder
A gas flow meter/recorder

A solid particulate meter/recorder

Any other instrument or measurement that may be considered necessary
8    Emission Limits    1.    Combustion efficiency:


Combustion efficiency (CE) shall be at least 99.00% The Combustion efficiency is computed as follows;

C.E=    % CO 2    x 100
% CO2 + CO
2.    The temperature of the primary chamber shall be 800 ± 50o C
3.    The secondary chamber gas residence time shall be at least 1 (one) second at 1050 ± 50o C, with 3% Oxygen in the stack gas.


4    Opacity of the smoke must not exceed 20% Viewed from 50 meters with naked eyes
5.    All the emission to the air other than steam or water vapour must be odourless
and free from mist, fume and droplets.

6.    The Authority may require that the certificate holder have tests carried out by an accredited institution to determine stack and/or ground level concentrations of the following substances.

No

Cadmium and compounds as    Cd Mercury    Hg
Thallium    Tl

Chromium    Cr
Beryllium    Be
Arsenic    As
Antimony    Sb
Barium    Ba
Lead    Pb
Silver    Ag
Cobalt    Co
Copper    Cu
Manganese    Mn
Tin    Sn
Vanadium    V
Nickel    Ni
Hydrochloric    HCL
Hydrofluoric acid    HF
Sulphur dioxide    S02
A 99.99% destruction and removal efficiency (DRE) for each principal organic hazardous constituent (POHC) in the waste feed where:

DRE = [(Win - Wout)/Win]*100
Where: Win = mass feed rate of the POHC in the waste stream fed to incinerator, and
Wout = mass emission rate of POHC in the stack prior to the release to the
atmosphere.

The average dioxin and furan concentration in the emissions should not exceed 80ng/m3 total dioxins and furans if measured for a period of 6 to 16 hours.

te:
All pollutant concentrations must be expressed at Oo C and 1.013 x 10 5 N/m2,
dry gas and 11% oxygen correction.

Oxygen correction is computed as:

Es =    21 – Os   x EM 21 - OM
Where:  Es    = Calculated   emission concentration at the standard percentage oxygen concentration
EM    = Measured emission concentration
Os    = Standard oxygen concentration
OM    = measured oxygen concentration

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