Performance of Fuel Oil Additive Tests

Certain Tests are performed to ensure the continuous working of fuel oil treatment in Fuel Oil

Power Plants and the reason is not only to monitor the affects arising by using these FO additives but also to regulate the necessary dosing according to the changing load capacity of the power plant

There are different Tests which are performed on periodic bases. Some are performed on Daily basis while some are performed on weekly and monthly bases. While there are certain equipment’s used to continuously monitor online readings of some particular changes arising such as O2 sensors, SO3 Monitor etc.

There are different types of tests which are performed to ensure the better performance of a fuel oil additive and continuous monitoring allow the perfect dosage of the additive used. Some of the Tests performed are:

Determination of pH and Free acidity of Fly ash and combustion residues.
Flue gas analysis using TESTO 340
Acid Dew Point Test using LAND’S Lancom 200
Unburned Carbon Reduction Test
Continuous SO3 monitoring using SO3 monitor

PH ANALYSIS AND FREE ACIDITY OF FLY ASH:

pH analysis is performed on daily basis after a 12 hour or 24-hour interval to check and assess the effect of Fuel oil additive in controlling both the slag builds up in the High temperature section and acid deposition in the cold end of boilers, process furnaces and other combustion units.

WORKING PRINCIPLE:

pH analysis is done of the ash sample collected using 1 gram of ash sample and dissolving it in distilled water using magnetic stirrer for 5 minutes and checking the pH reading. After the reading is taken it is mixed and stirred for 55 mints so that the MgO present can be dissolved efficiently and then the pH reading is recorded again after 55 mints which is usually greater than 0.2 to 0.5 from the pH reading recorded after 5 mints of stirring.

Once the pH is obtained it is than titrated with 0.1 N solution of NaOH to obtain the Percentage Free Acidity present by multiplying the NaOH ml used with 0.49 factor used for sulphuric acid H2SO4 which assess the production of SO3 in the process and hence can be used to control the production of SO3 by regulating the FO Additive dosing.

The standard pH for an optimized process is ranged from 3.5 to 4.5 while a pH lower than 3.5 exhibits acidic nature and hence indicates production of SO3 over the limits which can cause corrosion in Lower temperature sections by condensing into H2SO4.

EQUIPMENT USED:

It is a basic lab pH analysis test which utilizes the following equipment’s and chemicals:

pH meter
1-gram ash sample
Beaker
0.1N of NaOH
Magnetic stirrer
Analytical balance accurate to 0.01 gm
Distilled water

FLUE GAS ANALYSIS:

Flue gas analysis is performed on weekly basis and the purpose is to check the amount of flue gases leaving the stack. The experiment is performed at 100 meters of the stack through a duct by using equipment TESTO 340.

It’s an automatic test in which the percentage of Oxygen O2, Carbon dioxide CO2, Carbon monoxide CO, Nitrogen dioxide NO2 and Sulpherdioxide SO2 is checked before it leaves the stack as flue gas. The purpose of analyzing flue gasses is to keep the concentration of these gases in a permissible amount before leaving them in the environment therefore the stack used is of a greater height to disperse at a maximum height the hot gases, emissions and particulates that leave the boiler. At these heights the pollutants disperse in a very large area so that ground level concentrations are within permissible levels.

Higher stack flue gas flow means lower plant efficiency.

WORKING PRINCIPLE:

The probe is inserted into the duct through the flange extracting flue gases to measure their concentration. Testo 340 uses different sensors to measure the concentration of the gases in the flue gas. i.e. O2, CO, CO2, SO2 and NOX. Probe placement is important, and several factors must be considered when choosing a sampling location.

To get the most accurate measurement, the gas-sampling probe must be placed prior to any draft damper or diverter, so that the gases are not diluted, and as close to the equipment breach as possible so the gases have not cooled in the flue.

EUQIPMENT USED:

Testo 340 which includes a measuring module and a Flue gas probe attached through a filter.

ACID DEW POINT TEST:

Acid Dew Point Test is performed to check the acid dew point temperature of the flue gas containing SO3. Acid Dew point is that temperature at which the gaseous SO3 condenses in the liquid form of H2SO4 and hence causes corrosion in the low temperature sections. ADT is monitored on weekly basis and is minimized so that the exit flue gas temperature can be reduced to optimized value of around 140ºC thus increasing boiler efficiency.

WORKING PRINCIPLE:

The probe is inserted into the duct through the flange, and allowed to warm up until it reaches the temperature of the flue gases.

The air valve is then slowly opened to cool the probe tip. Acid condensation is indicated by a rise in electrical current through the sensor. Once the current reaches the 50uA the detector temperature is measured which is the measured Acid dew point temperature.

EQUIPMENT:

LAND’s Lancom 200 is used for measuring Acid dew point.

The equipment includes a Monitoring Unit normally operated inside its carry bag. It has a probe which is inserted in the flange where the ADT is measured. An air compressor is used to provide necessary local air supply to the equipment.

UNBURNED CARBON REDUCTION TEST:

This test is performed to check the reduction in the unburned carbon substances present in the fuel. This test is performed to assess the reduction in unburned substances and to monitor the effect on the boiler operation.

WORKING PRINCIPLE:

Ash sample is collected from the duct and 1 gm of ash sample is heated in the crucible using muffle furnace to up to 600ºC. The weights of empty crucible, with the ash sample and after heating the crucible in the furnace are recorded than using a certain formula unburned carbon reduction is calculated.

EQUIPMENT:

It’s a chemistry lab test and take around 2 to 3 hours. It uses the following equipment’s

Muffle furnace (to heat up to 900ºC)
Analytical balance accurate to 0.01 gm
Ash sample of 1 gm
Crucibles
Desiccator

SO3 ANALYZER:

In power generation SO3 measurements provide data to allow the operator to burn fuel in the most efficient way to minimize corrosion of the plant and limit acid discharges to the environment. Monitoring of SO3 is also important where it is formed as a by-product, e.g. in De-NOx systems.

In processes where H2SO4 is used or ore with large amounts of Sulphur is processed, the SO3 monitor can measure SO4 2- ions and show emission as mg/Nm3 or ppm.

The Pentol SO3 monitor has been designed to meet a wide range of measuring requirements.

1 – 200 ppm SO3
Flue gas temperature up to 400°C (up to 550°C with special probes)<
The instrument is portable and suitable for long and short-term measurements
The unit is auto-calibrating in a user defined cycle
An optional RS232 connector allows to log measurements on a laptop

Working principle:

The Pentol SO3 monitor is based on a wet-chemical process.

The gas sample is measured by means of a heated probe. In the probe head, the sample is cooled down and diluted in a mixture of isopropanol and water. The SO3 condenses and reacts to sulfuric acid in liquid phase, eliminating all problems related due to insufficient heating known from manual measurements.

The sample is then transported to the instrument by the peristaltic pump and reacts with barium chloranilate, colouring the sample according to the SO3 concentration. The concentration is then measured with a photometer that can be calibrated automatically.

This procedure allows to measure repeatedly and very accurate directly in the plant or in laboratories.

Performance of Fuel Oil Additive Tests

Performance of Fuel Oil Additive Tests

PH ANALYSIS AND FREE ACIDITY OF FLY ASH:

FLUE GAS ANALYSIS:

ACID DEW POINT TEST:

UNBURNED CARBON REDUCTION TEST:

SO3 ANALYZER:

Working principle:

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