INTRODUCTION Boiler Operation
On tank vessels to support smooth service and shipping, auxiliary planes are needed, including auxiliary boilers, which function as hot steam generators which will be used to heat the load, pump out the cargo, heat the fuel, control the air temperature if we sail in cold areas and are used for other purposes.
Boilers are required to always be able to produce sufficient steam for the needs on board. The availability of hot steam is
the absolute thing for the smooth operation of machinery that requires steam. Shipping and service can be disrupted if hot steam income is a problem because we do not know the safe and correct operation method so that the boiler is disrupted or damaged.
In the background of the importance of safe and correct operation of the boiler to support its performance so that it is always in a state that is always ready to operate and prime, in this paper we will try to describe: “OPERATION OF BOILER AND HOW IT CARE”
A . UNDERSTANDING BOILER
It is a fact that until now there are still many ships that use steam power installations, both the main installation and the use of auxiliary aircraft. In the steam tankers the results of the boilers are usually used as heaters, either fuel heaters, room heaters, water heaters, cargo heaters or for other purposes so that the ship’s operations can run smoothly.
Boiler or we can also call it a boiler is a closed vessel that can form steam with a pressure greater than the atmosphere of the atmosphere by heating boiler water inside it with hot gases from the combustion of fuel. A boiler or steam boiler must be equipped with equipment to help its performance so that the boiler operation runs safely. Boilers or boilers must have the following requirements:
- Can produce steam with a certain weight at a certain time too, and the pressure is greater than one atmosphere.
- The level of water produced in hot steam must be slightly higher.
- When using a steam heater, then the steam temperature at the last steam consumption does not change too much.
- Steam must be formed with as much fuel as possible.
- If the use of steam changes, the vapor pressure may not change much.
B. TYPES OF BOILERS AND APPEDANS / EQUIPMENTS
In motorized boats steam use is of course only used on auxiliary aircraft. Whereas for steamers, the main use of steam is to drive the main engine, while other uses are for auxiliary aircraft. Therefore the boiler or boiler can be distinguished according to the substances flowing into the pipes, namely:
a. Fire Pipe Kettle
Is a kettle where combustion gases flow in pipes while the kettle is flowing outside.
b. Water Pipe Kettle
Is a kettle where boiler water flows in pipes while outside there are combustion gases.
We already know that boilers must be equipped with apparatus and some equipment so that the boiler can run smoothly and to ensure the safety of the boiler. According to the law of steam, what is included in the appendance are:
a. Related to the steam room.
- This valve safety
valve has a function to prevent the pressure in the boiler not to exceed the work pressure determined according to the regulations.
- The main and auxiliary
valves are valves that are used to regulate the supply of steam for heating the cargo, while the auxiliary valves are used to regulate the flow to auxiliary planes. The valve must be installed as close as possible to the boiler and the valve must be open and closed properly and smoothly.
This tool is to show and know the vapor pressure of a connection that is in a kettle clearly and precisely, with this manometer the operation of the boiler will be safer.
b. Related to water space.
- Boiler filling
valve The function of this valve is to regulate the amount of filling water entering the boiler and prevent the boiler water from returning to the filling line.
- Spui Faucet or Blow down.
Is to remove part or all of the boiler water to remove dirt that settles at the bottom of the boiler.
- Glass Estimator
is a water controller inside the boiler.
Besides that there are additional tools, but not including appendices, namely:
- Brain Brain
- Salt Faucet
- Fire Line
- Stamp plate
In modern boilers, in addition to these devices are still equipped with other tools to enhance the usability of the boiler, namely:
- Advanced steam heater or OVO
- Air heater or LUVO
- Initial heating of boiler or ECO filler water
C. OPERATION OF BOILERS
a. Operation Preparation .
Make sure that the tools below have been checked before the boiler operation is carried out.
- Can produce steam with a certain weight at a certain time too, and the pressure is greater than one atmosphere.
- The Water Level Gauge or Water Level Guide
Drain the cock must be fully closed as well as the gauge cock at the top and bottom of the water level instructions, making sure that the desired water level from the drum drum can be indicated by the water level instructions. However the water level instructions indicate that the water level should not be below the safe water level in the event of a periodic change in water level ups and downs on the water temperature rise in the boiler.
- Pressure Gauge or Pressure Gauge.
Make sure Drain Cock is fully open and the needle shows zero. Pressure instructions are placed below so that it is easy to see.
- Blow Off Valve or Blow Down Faucet.
Make sure the center faucet and faucet blow down on the fully covered vessel. Take immediate action to do if there is a leak in this system.
- Water Feed Valve or Water Charging Faucet.
Keep the faucet stops charging water is always open to add water every time the water level can be controlled. Close the faucet to check the filling water so that there is no addition in the use of excessive filling water capacity.
- Steam Stop Valve or Stop Steam Faucet.
By opening or closing the controller of this faucet, make sure that the faucet is fully closed.
- Safety Valve or Security Faucet.
Make sure there are no errors that occur in opening the divider faucet manually (The Manual Valve Opening Device) and also the drain pipe in the body is opened.
- Air vent. Air Vent Valve or Faucet.
Open the air vent valve completely when the steam is first flowed, and the lid returns after that the air entering the boiler is discharged.
- Other Unit or Other Unit.
Avoid mistakes during operation, check the other units carefully and carefully.
b. Fuel Heating
One of the perfect requirements for fuel combustion is the presence of good heating and mixing between the fuel and air and the appropriate heat. The purpose of holding heating on fuel is:
- So that the oil becomes runny so that it is easily separated or cleaned from dirt and achieves perfect fogging viscosity.
- With temperatures as high as possible, the oil can be easily pumped to the point of combustion because the viscosity is already low, so the oil removal will run smoothly and immediately can be burned.
Heating is carried out until it reaches a temperature of around 10 ° C below the flash point and its viscosity is approximately 2 ° Engler. If heating exceeds the flash point, there will be difficulty during the trip to the combustion due to the high temperature resulting in the deposition of the pipe which will be attached to the pipe so that it will reduce the pipeline.
3 . Fuel combustion .
Basically fuel oil contains chemical elements carbon (C), hydrogen (H) and a little sulfur (S). Each of these elements in the combustion process with oxygen (O2) from the air will cause heat. In simple terms the chemical reactions in the combustion process can be written as follows:
C + O2 ® CO 2 + heat
2H2 + O2 ® 2H2O + heat
S + O2 ® SO2 + heat
From the above reaction it turns out that in the combustion process H2O is produced, namely water. This is where there is a difference of opinion about the amount of heat produced. To be able to achieve a perfect combustion, the ratio between the amount of oil and air must be good. In order to get the perfect combustion needed:
- The opaque oil kettle must be clean of all impurities that are solid or liquid.
- Oil must be heated to a certain temperature first.
- When leaving the combustion mouth the oil has sufficient speed and is atomized and can burn and will not hit the combustion wall.
- The incoming air has sufficient speed and has a good mixing method with the fuel so that each part of the oil burns out. For that the way to enter air into the combustion kitchen follows the direction of a rotation, and the air entering must be heated so that it can help carry out combustion.
d. Boiler Operation
1. Feed Water to the boiler or filling water to the boiler
- Open all faucet water from the cascade tank to the boiler as well as the air vents from the feed pump and the system.
- Turn on the security source from the boiler.
- Move the filling pump from manual to automatic. Also select the No.1 or No.2 filling pump.
- Press the button for the operation of the charging pump and make sure the pilot lamp is on, the pilot lamp lights up for the low water level as well as the low water level alarm buzzer.
- Make sure the filling pump motor runs smoothly and the heat is not excessive.
- Make sure the compound gauge and pressure gauge are working normally
- Check the pipe system for leaks.
- Turn on the stop switch for low water level buzzer alarms.
2. Ventilation of air from circulating fuel
- Open all fuel system faucets.
- The faucet cover cock from the fuel return faucet, also ventilation air from the fuel system and the filling pump.
- Increase the setting of the low temperature thermostat alarm according to the circulation of the fuel.
- Move burning to automatic operation and move the burning switch to the ON position.
- Open the cock air vent on the fuel return pipe for all air exhaust from the system.
- Check the fuel system for leaks.
- Make sure the fuel poma motor and fan force drop run soft and the heat is controlled.
- Make sure that the thermometer records according to the temperature of the fuel and there is no leak when passing through the nozzle pipe.
- If the fuel heating temperature is correct and there are no problems in each unit, turn on the alarm thermostat at normal temperature.
- Disposal of water every 35 minutes.
- The burning starts a few seconds after the burning pilot light is on.
- Examination during combustion
- Color, level of ignition and ignition stability
- Smoke color, gas leakage from the top and protectors.
- Vibration is not normal.
- If there is a problem, immediately stop burning and check the oil pressure, oil temperature and tip of the nozzle.
- Open the main steam faucet slowly to prevent tap water in the system.
- Check the system for leaks
4. Shut down or disposal
- Increase the vapor pressure near the maximum normal working pressure
- Close the main steam faucet, blow off the water surface.
- Burning is restarted, approaching the maximum normal working pressure.
- Turn off the combustion switch, press the lock stop operation and disconnect the power source.
- Close the filling system faucet, check the water level in the cascade tank of the oil in the tank daily before closing the main tap.
5. Cold starting or run in cold conditions
When vapor pressure falls to zero or especially in this case is a trial operation or a new boiler, consider the following:
- Since the inside of the boiler is cold, avoid igniting sudden burning. Do not ask for sudden vapor pressure but take good time until the pressure rises to 1 Kg / cm².
- Check all systems and take action to prevent things from being desired.
D. CORROSION ON BOILERS
a. Form of Corrosion in Boilers.
In this chapter various forms of corrosion will be described in the boiler. Corrosion can occur in the water side and on the side of the smoke gas material. What is meant by corrosion is the unwelcome touch on the material by the chemical influence on the surface. Corrosion on the water side can be prevented by handling water well, while corrosion on the gas side is more complicated. Prevention is mainly located in the field of construction, in the sense of the word in the form of boilers, piping patterns, the location of advanced heaters, regulation of the temperature of the smoke gas coolant, and so on. Current boiler designs are mainly shown in the prevention of corrosion on the gas side of the smoke.
Except for precious metals gold, silver and platinum metals are present in nature as oxides, in the sense of the word compound with acids. The processing of pure metals for practical application occurs through a reduction process as follows:
MeO + R ® Me + RO
MeO is a metal oxide, R means reduction, metal Me and RO oxide means a reduction. For example the reduction of Fe 2 O 3 with CO, such as taking place in a high kitchen is as follows:
Fe 2 O 3 + 3CO ® 2Fe + 3CO 2
Although most metals are not in their pure form but are applied as alloys, the metal will try to return to its original form of oxide. Therefore oxides are considered natural symptoms. Eradication every year requires huge costs for repairs and means of eradication on the one hand and material losses on the other. Corrosion can be divided into the meaning of its manifestations, namely:
- Touch on all surfaces.
- Local touch (formation of puddles, indentations).
- The inter-crystal line, which is touching on the crystal boundaries at or near the surface.
Other parts are according to the corrosion mechanism:
- Pure chemical corrosion.
- Koroso electro chemistry
b. Causes of Corrosion in Boilers
1. Corrosion is caused by boiler water
Corrosion will occur in the part where water is applied continuously if the smoke funnel is above the combustion chamber and shows the water pipe to the combustion chamber, when some corrosion occurs immediately overcome with chemical reactions, when the reaction is rapid then corrosion does not take root. If, however, washing with a chemical reaction will slow down the corrosion. Some of the causes of corrosion are negligence in the blow off, not cleaning the cleaning in the boiler, insufficient circulation of boiler water and excessive use.
2. Corrosion caused by other substances
a. Gas reaction in boiler water
Iron rusts or corrodes due to submerged in water or high temperatures and the use of corrosive materials. In this case the oxygen contained in the water supply is very good for burial or perforation, this happens in the steam room where there is a lack of change of water, the running of the water from the boiler drum and pipes, water pipes and economiser. Carbon acid results from carbon dioxides when dissolving in water and reacting with iron to produce carbon iron. Carbon iron reacts with oxygen to produce a second iron oxide. Since this reaction process takes place where carbon dioxide is liberated, thereby accelerating other corrosion cycles.
b. Corrosion by nature
One part of perforation or perforation, expansion of the coring area is caused by the separation of acids in boiler water and the separation of large / fat acids from animals or woven plants in boiler water.
c. Corrosion by salt
Corrosion of magnesium chloride in the boiler occurs until rooted. This is due to the separation of the results of hydrochloric acid in boiler water and this does not stop in perforation but stops in the form of fish scale scales do expansion, which often occurs in parts showing for strong heat where air bubbles are difficult to release.
d. Corrosion by excessive heat vapor.
Steam is a separator in hydrogen and oxygen when the temperature of the steel surface rises to centrigrade 400 degrees or higher. Oxygen is the corrosion section of a steel section.
E. AIR BOILER AND WATER BOILER FILLER
a. Definition of boiler water and boiler fill water
We need very pure water to fill the boiler and to add to the effects of leaks that occur in the circulation of the circle, namely heating – evaporating – condensing with the intention of energizing. For this purpose various aircraft are in circulation, namely steam boilers – turbines – condensers and other auxiliary aircraft such as pumps, load heaters, fuel heaters and so on.
During circulation, there is a 2% loss of water, this loss must be replaced. On ships, this is done by evaporation of sea water. The steam is condensed again and as distilled water is stored in the supply tank, from this tank it is reinserted in circulation but there are still many vessels taking supplies of boiler feed water from the ground.
So the definition of boiler fill water is water provided to add boiler water that has been lost in circulation. Whereas boiler water is water that has participated in or circulated in the cycle of steam, until it is condensed, and becomes steam again.
b. Condition of boiler water filler
In principle, filler water must fulfill several conditions, namely:
- As far as possible the O 2 and CO 2 gas is limited, which dissolves in the boiler water causing an oxidation reaction to the metal or iron pipe in the boiler.
- The levels of kitchen salt (NaCl and Na 2 SO 4 ) are as low as possible because these salts cause boiler water to boil.
- If the boiler fill water is deposited, it must be in a condition that can be removed from the boiler.
- Water filler must be non-aggressive in iron, tends to Ph to base.
c. Handling of boiler water and boiler fill water
1. Soften the thermic in the boiler fill water
This is done outside the boiler in what is called a deaerator, gas emitter or waster. A mixed face heater, where condensate is mixed with steam. The mixture temperature is approximately 110ºC. Bicarbonate is described as follows:
Ca (HCO 3 ) 2 + Q ® CaCO 3 ¯ + H 2 O + CO 2 Mg (HCO 3 ) 2 + Q ® Mg (OH) 2 ¯ + 2CO 2
CaCO3 and Mg (OH) 2 as fine mud by water are brought into the boiler. With other substances in boiler water it is coagulated into a floating fine mud which can easily be drained.
2. Softening chemicals in boiler water
After thermic softening, temporary hardness is lost, meaning that Ca ++ and Mg ++ ions which are bound to HCO 3 – arelost, now there are still Na ++ , SO 4 – – and Cl – now in water . Ca ++ and Mg ++ must be bound in such a way that substances that do not produce harmful deposits (stone boilers) and can easily be drained. For softening this chemical Na2Co3 (soda) can be used, Na2Co3 in certain circumstances decomposes as follows:
Na2CO3 ® 2Na + + Co3 – –
In the boiler arises unwanted CO2, while the Ph of water rises, because the H + ions are pulled from the water are also maintained there is an excess PO4 – as much as 15 to 25ppm PO 4 . On the advantages of PO 4 there is no more Ca ++ because it is changed to:
2PO 4 + 3Ca ++ ® Ca3 (PO4) 2 ¯
Calcium phosphate does not dissolve and is excluded from draining. Softening water is said to be under control if it maintains certain PO4 advantages for certain Ca ++ and Ph for Mg ++ , also for other reasons that boiler water has a certain Ph (corrosion). Softening of the water is necessary because the condenser is somewhat leaky Ca ++ and Mg ++enters the cooling water system. With this supply of Ca ++ and Mg ++ is entered into the system.
3. Supervision of boiler water and boiler fill water.
Basically the supervision carried out on boiler water and boiler fill water is the same which includes several things, namely: