Thermal Oil Boiler on Shipyards
Steam boiler systems are divided into feed water systems, steam systems and fuel systems. The feed water system supplies water to the boiler automatically and according to the steam boiler needs. Various faucets are provided for maintenance and repair needs with (example: blowdown). The steam system combines and checks steam production in the boiler. Steam moves across the system pipeline when used. In the whole system, the steam pressure is controlled using a tap and monitored by a pressure monitor. The water provided to the boiler to convert to steam is called feed water. Feed water comes from two sources, namely condensate or steam which condenses back from the process and raw water
already processed which must be fed from outside the boiler room of the plant system. To produce higher boiler efficiency, use an economizer to heat feed water initially using waste heat in the exhaust gas. The fuel system is all the equipment needed to supply fuel to get the desired heat. The equipment needed in the fuel system depends on the type of fuel used by the system.
The working principle of the steam boiler
After passing through the process carried out before working on the core process (pretreatment) in condensate water, feed water is pumped into the economizer. In the economizer the preheating takes place using the waste heat in the chimney. Initial heating is done to increase the efficiency of the boiler.
Then the feed water enters the boiler, before feed water is given chemichal according to the prescribed dose. And the feed water that gets warmed in the boiler changes the stage to steam (steam) and is ready to be distributed
Image related Once the steam has changed the stage again to condensate water, it can return to the pump into the boiler again. Condensate water is only used to replace water loss due to the blowdown process
a. fuel analysis.
For design and comparable purposes, the reference standard for fuel oil is = 6 fuel oil (6 fuel oil (bunker C) which has characteristics as below
The heating value which is higher than the fuel reference standard is determined by a bomb calorimeter and corrects for heat type at a fixed pressure of 18,500 Btu / Lb. the base temperature for heat content is estabilished like 100F. For the design and calculation of heat balanced the heat value of the oil correction for additional heat added (in Btu’Lb) in heating the oil to temperature (assumed 200F) (which) is important for fogging according to the following expression:
Heat added = 0.46 (break down to atomic temperature – 100F)
the total heating value of the reference oil is, therefore, 18,546 Btu / Lb and is used for all types of fogging which includes fogging water vapor.
b. Combustion Air
oxygen is needed for combustion provided by combustion air. other elements of air act as diluents. air is a mixture – as distinguished from a chemical mixture – of oxygen, lime, and the amount of small carbondioxide, water vapor, argon, and other noble gases. the basic composition of dry air for combustion purposes is considered as:
gas which is rarely included as part of elemental glue.
air is assumed to be provided to the forced draft plan for a temperature of 100F, a humadas family of 40%, and a barometic pressure of 29.92 in Hg. under the air conditions like that have the following physical properties.
based on the fuel ahead and their standards, the analysis will show a staticometric or theoretical dry air quantity to burn a pound of fuel is 13. 75 lb. from this, the amount of air follows for various excess percentages specified:
The final analysis of the fuel that is really found is varied from the standard reference fuel. illustrates 17 shows the effects of this variation on the theoretical air needed for combustion. for example, a fuel consisting of 87.25C, 12.0 H2, 0.2S, 0.4o2, and 0.15N2 will require 3.0 percent more air for stoichiometric combustion (+ 3.8% for / because of H2, – 0.4 forC, – 0.4% for S) 
To reduce dry gas loss over the stack, the gas funnel weight / load must be held for a minimum consistent with the provision of enough air to completely burn the fuel. recognize the one in front, an operator needs to observe the result with a certain fuel oil bunkered and adjust the excess air to achieve complete combustion. however, in the case of a case, the design of a boiler is based on an air-fuel ratio that is sufficient to provide 715% excess air.
while there are many oil burners and combusition control systems that can operate successfully with excess air, use 15% for / because the design goal ensures sufficient surface heat transfer and forces the draft to blow with sufficient capacity. for / due to additional margins, where / if there is no air heater installed, 20% excess air is often used.
Comparison of air fuel or excess air is often discussed in terms of CO2, which is ready to be obtained from a steam boiler operation for the aid of an analysis tool. an article that reads 14% Co2 corresponds to approximately 15% excess air. illustrating 18 performances [is] the relationship between [a] Co2, O2 and excess air.
such as heat transfer and draft calculation based on the gas air funnel weight / load, the use of the term “percent CO2” which is a volumetric measure being an important meaning only in comparing oil burner performance. is most useful where oil is used from a wide variety of analyzes of the standard fuel reference. The excess AI, or air comparison fuel, can also be determined conviniently by using an oxygen analyzer, a reading of 3% oxygen corresponds to approximately 15% excess air.
The efficiency of the boiler is described as a ratio of heat in. heat output is equivalent to heat entering less that loss.
Heat output can also be defined as the enthalpy difference between feed water entering the boiler or economizer, if installed, and steam leaving the boiler (both superheated and desuperheated). When a steam air heater is installed, the heat input from the steam is charged to the boiler’s total heat input and efficiency becomes:
Efficiency = Hi + Ha-HLHi + Ha
Where Ha heat is added above 100 F to combustion air by heating Where Ha is added to the heat at the beginning of the design process, one of these expressions is solved for Hi heat input, from which the weight of the fired oil is easily determined by dividing by the heat value of the fuel design, usually 18,546 Btu / lb. All amounts are determined based on the hourly flow rate.
The required boiler efficiency is usually determined by specifications or heat balance. Along with the steam design pressure and temperature, it sets the number and arrangement of the heater surface installed in the boiler and economizer. The design of vapor pressure and saturation temperature is adjusted according to the “sink” of the effective temperature of the boiler generator bank, and feed water set that of the economizer.
In the case of an air heater installation, the sink is the inlet air temperature for it, usually 100 F. The typical curve of efficiency versus load for the steam generator is shown in Fig. 19. Note that efficiency decreases with steam output increasing. The quantity of hot exhaust gas that will increase is cooled as more fuel is consumed to increase steam output. As is the case, the fixed effectiveness of a number of warming arises depreciation and decreased efficiency. This is common to the surface size of the boilers for merchant vessels where desired efficiency is ranked in relation to “ABS power”. The efficiency at the maximum or minimum numbers then is a function of this design point and must be at the efficiency of the characteristic curve.
A practical ceiling on boiler efficiency is imposed by the need to maintain the temperature from the top of the gas up above the dew point of the chimney gas. It minimizes sulfur deposites and corrosion from the final cold from heat exchangers and ductwork. In economizers, corrosion results in leakage and forced sealing outages; therefore, it is common practice to maintain at least a feedwater temperature of about 280 f, which results in one chimney gas temperature from around 315 to 320 f and limits the risk of corrosion.
In a regenerative air heater, a corrosion failure is not due to non-catastrophic; therefore, a low stack temperature (280 f or less) is practical and the boiler efficiency is higher. Cycle efficiency can be further enhanced through the use of payment water heaters forcing altitudes to provide feedwater at temperatures which are impractically high on one recurrent economizer.
d. Selection of oil burning
The choice of the type and number of oil burns used is dependent on available draft loss, the dimensions of the furnace, and the fairing boiler rating. High capacity, wide range burners are usually selected for installation by reducing the number of burners requiring and simplifying maintenance and operation. Control costs and safety equipment, like this maintenance, because that must at least be maintained.
the size and arrangement of the engine room often affects the location of the burner. It is desirable to place adjacent burners into the control console for ease of visual monitoring and availability. In both boiler drums, burners can be installed on the front of the furnace for walls, roofs or sidewalls.
In front of the boiler, gas was shot parallel to the bank boiler.
They are compared to a temperature of 90 – deg directing the screen line, and as the depth of a fireplace is usually the shortest dimension tends to be gas to hoard based on the back of the wall. This heavy concentration of the gas behind the gas temperature dishevels, and forecasts of the water vapor temperature and superheater metal tubes the temperature is more difficult.
On the other hand, the roof shoots gas which is uniformly distributed over depth from the cage. Since heigth hearth furnaces are usually the longest dimensions, there is less tendency to concentrate the gas before they are directed into a filter superheater.
Side firing, with burners on the side walls, requires careful attention to be specific to the design details. Since the gas process has no rotation before entering the screen, making a limp tends to be very long. This can result in flashing of the screen and the superheater bank with one advers influencing the superheater temperature tube and the learning temperature.
We usually, at least two oil burns are used so that one burner can be shot when cleaning or changing the old sprater on the other.