The term “boiler efficiency” is often substituted for thermal efficiency or fuel-to-steam efficiency. When the term “boiler efficiency” is used, it is important to know which type of efficiency is being represented. Why? Because thermal efficiency, which does not account for radiation and convection losses, is not an indication of the true boiler efficiency. Fuelto-steam efficiency, which does account for radiation and convection losses, is a true indication of overall boiler efficiency. The term “boiler efficiency” should be defined by the boiler manufacturer before it is used in any economic evaluation.
Excess air provides safe operation above stoichiometric conditions. A burner is typically set up with 15% to 20% excess air in higher firing ranges. Higher excess air levels result in fuel being used to heat the air instead of transferring it to usable energy, increasing stack losses and significantly decreasing efficiency. Boilers with lower excess air throughout the operating range have higher efficiencies.
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.
This is because, under normal circumstances, the exhaust temperature of the boiler cannot completely condense the water in the flue gas, and the difference between the low calorific value and the high calorific value is mainly in the part of the latent heat of vaporization, so the low heat is used. The value is calculated to reflect the true efficiency of the boiler. However, there will be some special circumstances. For example, if the boiler is a condensing boiler, the calculation of the condensed water portion should be calculated using the high calorific value.
1. Your existing system is inefficient
Efficiency is key when it comes to plant heating. Utilizing efficient equipment can save your company a significant amount of money in the long run and it is better for the environment. If you know that your existing system is not as efficient as it could be and it is in need of repair, it may be worth looking into thermal oil system replacement.
2. Your existing system features helical coil technology
Helical coils are common in thermal oil heaters from most manufacturers. But there are many reasons why serpentine coils are the better way to go when it comes to thermal fluid heating. Repairs to helical coils can be so expensive and time consuming that in many cases you are better off investing in new equipment – and it is well worth it to consider a new thermal oil system that features serpentine coil technology instead.
In the case of a thermal oil heater in a high-temperature operation state, if it encounters an emergency situation of power failure, its correct treatment is:
When the circulating oil pump cannot operate normally due to power failure, the heat transfer oil in the furnace tube will exceed the allowable value in a short time due to the residual heat of the furnace. At this time, the cold oil switching valve should be opened to release the cold oil in the expansion tank. And sent to the oil storage tank. At the same time, wet coal pressure or emergency shutdown is required and needs to be completed within 5 minutes.
In addition, we need to pay attention to not to put the oil in the expansion tank clean, otherwise the system will inhale air and cause problems. An oil level mark can be made on the oil level of the oil storage tank. When the cold oil is replaced, the valve can be closed in time to avoid the expansion of the expansion tank and the oil storage tank.
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.
