Best practice no 21

Number 21

Octuber 2023

BEST

Manufacturing Engineering PRACTICE

COMBUSTION TESTING PROCESS AND DOCUMENTATION

COMBUSTION TESTING PROCESS AND DOCUMENTATION

With today ’ s high energy costs and the need to reduce emissions, it is necessary to obtain data from the steam boiler at different firing rates during the combustion testing process. The combustion process in the steam boiler transfers the chemical energy to thermal energy, which in turn is absorbed by the water in the boiler. To measure combustion process and efficiency, the plant must have equipment or have an outside firm analyze the flue gases from the combustion process. Combustion refers to the rapid chemical union of oxygen with fuel.

COMBUSTION OVERVIEW

OUTSIDE COMBUSTION TESTING CONTRACTOR

COMBUSTION TESTING DATA SHEET

COMBUSTION OVERVIEW

The perfect combustion of fuel would result in:

CORRECT COMBUSTION TESTING DATA SHEETS

• Carbon dioxide • Nitrogen • Water vapor • Sulfur dioxide

The oxygen needed to burn fuel is obtained from the air. Air is a mechanical mixture that contains by weight 21% oxygen, 78% nitrogen and 1% other gases. Only oxygen is used in combustion. Nitrogen is an inert gas that has no chemical effect during combustion. The chemical combination obtained during combustion results in the release of thermal energy. In reality, what happens is a rearrangement of the atoms of chemical elements into new combinations of molecules. In other words, when the temperature of the fuel (in the presence of oxygen) increases to the ignition point, a chemical reaction occurs. The fuel begins to separate and join with specific amounts of oxygen to form a completely new substance. Thermal energy is released in the process. Perfect combustion is the goal. However, this has until now been impossible to achieve either in a boiler or in the cylinders of an internal combustion engine. In theory, it's simple. It consists of putting each particle of fuel (heated to its ignition temperature) in contact with the correct amount of oxygen.

FIRE TRIANGLE

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REVISION DEL FORMATO: C

FECHA DE EFECTIVIDAD DEL FORMATO:10/03/2022

The combustion process begins with the application of a heat source to a sufficiently rich mixture of fuel and oxidizer, producing a rapid oxidation reaction of the fuel, which manifests itself in the form of a flame.

TABLE WITH BASIC OXIDATION REACTIONS OF FUEL COMPONENTS

COMBUSTION PROCESS

What is combustion theory? It is the set of physicochemical processes by which part of the internal energy of the fuel is released in a controlled manner. A part of that energy is going to manifest itself in the form of heat and that is what interests us. We know the reaction of a chemical element with oxygen is called oxidation. Combustion is nothing more than an oxidation reaction, in which a large amount of heat will normally be released.

FOR-IM-024

REVISION DEL FORMATO: C

FECHA DE EFECTIVIDAD DEL FORMATO:10/03/2022

OUTSIDE COMBUSTION TESTING CONTRACTOR

If an outside firm is used for the combustion testing procedure, the plant needs to ensure the company and individual are qualified to conduct the combustion test. A number of items should be provided by the outside firm:

1. Insurance documentation to meet the plant requirements.

2. Standard operating procedures (SOPs) on the combustion testing process

a. The SOP should be a step by step documented procedure. A typical SOP is five to eight pages in length

3. Validation and calibration of the combustion analyzer and any other test instruments used for the combustion testing

4. A sample of the report that will be delivered after the testing is completed

5. A sample of the combustion testing data sheet that will be used during the combustion testing procedure

COMBUSTION TESTING DATA SHEET

It is extremely important to take all data during combustion tests to establish boiler benchmarks and compare them to the original boiler manufacturer's benchmarks. Do not allow combustion testers to provide the plant with only the printouts from a combustion analyzer. This is only a very small percentage of the information needed to properly manage boiler operation and energy .

CORRECT COMBUSTION TESTING DATA SHEETS

The combustion test sheet must show elements such as the fuel pressure to the burner, the air pressure in the air chamber or duct, the temperatures of the combustion gases, etc. are an example of the required elements. All data must be taken at ten different percentages of the boiler combustion load.

When there is an excess of air, it indicates the amount of air present in the reaction.

 = 1 for the exact amount of air,  = 1.5 for 50% of the amount needed

When,

 < 1 The amount of air is insufficient to consume all the fuel.

When,

 > 1 The amount of air is greater than that necessary to consume all the fuel. We will have plenty O 2 and we will continue to have CO Excess air coefficient Most combustions do not take place under these ideal conditions (complete and stoichiometric), the main aspect to consider will be the possibility that the combustion takes place with excess or lack of air. To characterize the proportion of oxygen, the par ameter “coefficient” is defined . of excess air” :

n = volume air per air fuel unit / Comburent Power

n = 1: Stoichiometric Combustion

n < 1: Air defect, called rich mixture

n > 1: excess air, the mixture is said to be lean

FOR-IM-024

REVISION DEL FORMATO: C

FECHA DE EFECTIVIDAD DEL FORMATO:10/03/2022

Combustion Diagram

They are a very valuable tool for controlling combustion, since from the composition of the gas and fumes you can determine the type of combustion that is taking place and have a technical criterion to adjust the process and make it more efficient.

What this diagram seeks is to obtain a  = 1 through the air-fuel mixture .

The orange stripe will indicate the boiler's operating range.

Smoke Temperature (St) / Ambient Temperature (At)

The room temperature is measured with the room thermocouple, otherwise it is taken from the smoke probe in phase 0.

The flue gas temperature depends on the boiler technology.

What is a Combustion Gas Analyzer?

Just as doctors use equipment to monitor people's health, combustion technicians use flue gas analyzers to monitor equipment such as furnaces and boilers.

A combustion gas analyzer is a robust piece of equipment that monitors the gases generated in the combustion processes. This will help you know how efficient your process is and how many emissions it is generating.

Combustion gas analyzers are equipment capable of measuring the exact amount of each of these gases that can be toxic to humans and can become explosive in their work environment.

They serve us for environmental control, combustion gas analyzers determine how much fuel is being burned properly and tells us what the efficiency of combustion is, what combustion components are not being burned and also monitor compliance with national and regional standards.

It helps us as indicators in saving fuel, depending on each combustion process, between 20% and 50% of fuel can be lost in the chimney. Combustion gas analyzers help determine the efficiency of the fuel that is having in the process.

Carbon Dioxide CO 2

Gas analyzers calculate from the measured O 2 and the stoichiometric (or maximum) CO 2 specific to each fuel, which is why they manage a maximum CO 2 when turning on the analyzer.

FOR-IM-024

REVISION DEL FORMATO: C

FECHA DE EFECTIVIDAD DEL FORMATO:10/03/2022

Carbon Dioxide: CO 2

Carbon monoxide is the product of incomplete combustion (an indicator of combustion quality) and is inversely proportional to the amount of oxygen. The excess air will depend on the type of combustion and fuel.

When equipment is poorly carbureted with high parts per million of carbon, it can cause death, depending on the hours of exposure.

death after 1 hour

unconscious after 1 hour

lethal after 2 hours

maximum exposure level

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REVISION DEL FORMATO: C

FECHA DE EFECTIVIDAD DEL FORMATO:10/03/2022

Combustion Values

The values shown in this image vary for each gas analyzer.

FOR-IM-024

REVISION DEL FORMATO: C

FECHA DE EFECTIVIDAD DEL FORMATO:10/03/2022

Results Interpretation

O 2 ............................... 0.8% CO.............................. 1917 ppm Performance............... 95.8%

O 2 ............................... 2.1% CO.............................. 594 ppm Performance............... 96.5%

FOR-IM-024

REVISION DEL FORMATO: C

FECHA DE EFECTIVIDAD DEL FORMATO:10/03/2022

O 2 ............................... 4.9% CO.............................. 105 ppm Performance............... 96.7%

O 2 ............................... 5.5% CO.............................. 31 ppm Performance............... 97.2%

FOR-IM-024

REVISION DEL FORMATO: C

FECHA DE EFECTIVIDAD DEL FORMATO:10/03/2022

O 2 ............................... 16% CO.............................. 38ppm Performance............... 84.1%

O 2 ............................... 15.3% CO.............................. 39ppm Performance............... 85.5%

FOR-IM-024

REVISION DEL FORMATO: C

FECHA DE EFECTIVIDAD DEL FORMATO:10/03/2022

O 2 ............................... 8.9% CO.............................. 31ppm Performance............... 91.7%

FOR-IM-024

REVISION DEL FORMATO: C

FECHA DE EFECTIVIDAD DEL FORMATO:10/03/2022

CLAYTON DE MÉXICO S. A. DE C. V.

FORMATO DE AJUSTES FINALES PARA EQUIPOS MODULANTES

Nombre del Cliente: (CUSTOMER)

Fecha: (DATE)

Dirección: (MAIL) Modelo: (MODEL)

No. de Serie: (SERIAL NUMBER)

PUNTO (POINT)

1

2

3

4

5

6

7

8

9

CARGA (%) (RATE)

20

30

40

50

60

70

80

90

100

COMBUSTIBLE (FUEL)

AIRE (AIR) COMBUSTIBLE GAS (GAS) COMBUSTIBLE DIESEL (OIL)

VÁLVULAS SERVOMOTORES (ángulo en °) (SERVOMOTOR VALVES) ANGLE IN °

O (%) (OXIGEN) EXCESO DE AIRE (%) (AIR EXCESS) CO 2 (%) (CARBON BIODIXO) CO (ppm) (CARBON MONOXIDE) NOX (ppm) (NITROGEN OXIDES) SO 2 (ppm) (SULFUR DIOXIDE) PRESIÓN DE AIRE VOLUTA SUPERIOR (‘’.c.a.) (UP VOLUTE PRESSURE AIRE) PRESIÓN DE AIRE VOLUTA INFERIOR (‘’.c.a.) (LOW VOLUTE PRESSURE AIR) PRESIÓN DE ALIMENTACIÓN (FEEDWATER PRESSURE) TEMP. TANQUE CONDENSADOS (°C) (CONDENSATE TANK TEMPERATURE) TEMPERATURA DEL DISPLAY (°F) (DISPLAY TEMPERATURE) TEMPERATURA DE LA CHIMENEA (°C) (STACK TEMPERATURE) FACTOR HUMO (SMOKE FACTOR) TIRO DE CHIMENEA (mm) (SHOOTING OF FIRE) VARIADOR DE VELOCIDAD (Hz) (SPEED VARIABLE DRIVE) PRESIÓN COMBUSTIBLE GAS (‘’. c.a) (GAS FUEL PRESSURE) PRESIÓN COMBUSTIBLE DIESEL (lb/pulg2) (OIL FUEL PRESSURE) SEÑAL DE FLAMA (SIGNAL FLAME) EFICIENCIA (%) (EFFICIENCY)

CLAYTON DE MÉXICO S. A. DE C. V.

FORMATO DE AJUSTES FINALES PARA EQUIPOS MODULANTES

PUNTO (POINT)

1

2

3

4

5

6

7

8

9

PÉRDIDAS EN LA CHIMENEA (%) (STACK LOSS) PRESIÓN DE GAS – ALTA (lb) (HIGH GAS PRESSURE) PRESIÓN DE COMBUSTIBLE – QUEMADOR (lb) (BURNER PRESSURE)

MTLC-1 (Watlow modelo SF)

MTLC-2 (Watlow modelo SF)

PRESIÓN DE VAPOR (STEAM PRESSURE)

Nombre del Técnico de Servicio: (NAME SERVICE TECHNICAL)

Nota: Anexar a este reporte las impresiones del analizador de gases (NOTE: ATTACH TO THIS REPORT PRINTS THE GAS ANALYZER)