Category: Steam Generators

In all modern power plants, boilers raising steam at pressures greater than 100 bar are universally used. These are called high pressure boilers. They offer the following advantages: 1 Boiler Circulation There are four types of boiler circulation as follows. 2 Advantages of Forced Circulation Boilers The advantages of forced circulation boilers are as follows:…

Figure 3.6 shows the Stirling boiler, which comes in a water tube type in which three steam drums are connected together by the banks of bent water tubes. These tubes stand nearly in a vertical position near the rear end while they slope steeply over the fire at the front end. The baffles deflect the products…

A set of superheater tubes is provided to superheat steam which enters these tubes from the steam space in the boiler shell. The superheated steam can be taken out to the steam stop valve, through the steam pipe. The lower part of the downtake header has a mud box attached to it to collect the…

Figure 3.5 shows a stationary type Babcock and Wilcox boiler. It consists of a large number of parallel tubes inclined at an angle which varies from 5° to 15° to the horizontal which connect the uptake header with the downtake header. These are connected to the shell having a substantial quantity of water in it. The…

For pressures above 10 bar and capacities in excess of 7000 kg of steam per hour, the water tube boiler is used almost exclusively.

The Cochran boiler, shown in Fig. 3.4, is a multi-tubular, internal furnace vertical fire tube boiler having several horizontal fire tubes. Its normal size is about 2.75 m shell diameter and 6 m height of the shell. The steaming capacity is about 3500 kg/h. The flame and hot gases produced as a result of burning fuel…

The locomotive boiler shown in Fig. 3.3 is an internally fired horizontal multi-tubular portable fire tube boiler. It is specially designed to cope up with sudden variations in demand of steam even at the cost of efficiency. The pressure range is up to about 21 bar and can raise up to 55−70 kg per square metre of…

In construction and appearance, it is similar to the Lancashire boiler except that here, instead of two flue tubes, only one is used. Its capacity and working pressure range is low. Its shell is usually 4−8 m in length and 1.25−1.75 m in diameter. Its working pressure is about 11.5 bar and can raise steam…

The superheater used with Lancashire boiler is shown in Fig. 3.2. The arrows show the path of the gases, when the superheater is in commission.  When superheated steam is to be produced, the dampers are closed and opened so that the flue gases pass on to the superheater flue at the back and travel towards the…

1 Fire Tube Boilers Lancashire Boiler It is a stationary, fire tube, horizontal straight tube, internally fired, natural circulation boiler. Its normal working pressure range is up to 15 atmospheres and evaporative capacity up to approximately 8000 kg/h. The size varies from 7−9 m in length and 2−3 m in diameter. The three sectional views…