Condensing boilers can achieve up to 98% thermal efficiency, compared to 70%-80% with conventional designs (based on the higher heating value of fuels). Typical models offer efficiencies over 90% when the return water temperature is at 110 ºF or less; the lower the return water temperature, the higher the efficiency gain.
In order to improve the combustion efficiency of the boiler, in a large boiler, the combustion air is not supplied all at once, but is supplied in two times, one is supplied with the fuel that controls the rate of combustion as well as the amount of fuel that can be burned,and the other is directly supplied to the combustion process that that improves combustion efficiency. The primary air rate of the boiler refers to the proportion of the primary air. If the total air volume is 100% and the primary air rate is 70%, the secondary air rate is 30%.
Package boiler is a boiler that had been fabricated and available as a complete package. The entire pressure parts have been assembled in the workshop and ready to be sent to the field or site where power plant is located. On the field/site requires only connection and integration of course work in electrical connections, water pipes, steam pipes and fuel piping system to operate. Package boiler is one of classification of boiler based on erection. Design package boilers in general are the type of Fire Tube Boiler and have made up shell and tubes. This type has high heat transfer both radiation and convection.
The combustion air preheater is definitely one of heat exchanger applications. Based on Figure 1 below, flue gas simply leaves steam boiler and passes via air preheater. The combustion air is passed through this equipment too to increase its temperature before being combined with boiler fuel.
Because the temperature of combustion air is lower than the temperature of flue gas, combustion air receive heat transfer from flue gas through combustion air preheater in the process of convection heat transfer. The heat transfer make temperature of flue gas lower and consequently minimizes its heat loss and also decreases the air temperature to stack.
Economizer is one of steam boiler’s equipment which is used to heat feedwater before it is supplied into steam drum. Economizer is the heat exchanger equipment to increase boiler efficiency by absorbing heat recovery of flue gases. The lower temperature of flue gas out from stack, the heat loss will be less and the fuel which is needed to convert water into steam will be also less in certain circumstances. So it can be said that economizer can save the fuel efficiently. Economizer will make temperature of feedwater higher, so steam boiler can produce steam easily.
Reliability is absolutely essential to optimal boiler performance. In order to achieve the highest degree of dependability in a boiler it is important to identify and address the primary causes of boiler problems. One of the most common issues that can compromise a boiler is poor water quality.
The effect of water quality on boiler performance is a huge concern for plant owners and operators. Premature boiler failure often occurs as a result of poor or inconsistent feed water quality. Hard water elements in feed water are responsible for a number of issues:
Boilers are often distinguished by fuels that power them. The kind of fuel makes an essential difference in operating costs and environmental impact, so it’s important to learn about the various types of boiler fuel.
Coal, is a common boiler fuel. It dominates the global energy arena due to its abundance, affordability and wide distribution across the world. The most commonly used coal fuels include anthracite, bituminous coal, sub-bituminous coal, lignite and peat.
Any unusual noises should always be treated seriously.
One of the first things to check if a boiler is unusually noisy is the boiler's thermostat. If the thermostat is malfunctioning, water can become too hot and begin to boil, which could cause loud noises. If the thermostat is broken it may need to be replaced to prevent the water from heating up so much.
Another reason for a noisy boiler could be mineral deposits. As the water heats up inside the boiler, minerals may sink to the bottom of the tank and affect the heat exchange. This may create hot spots within the boiler in which water is overheated, leading to loud noises.
Low water pressure is also a concern that can result in loud noises. If water pressure is low, the boiler is tend to be overheat.
