Boiler has emerged as an important tool of industry with a high degree of versatility, a source of hot water and or steam. It has found applications in textile, pulp and paper, sugar, organic and inorganic chemicals, dyes etc. The requirement of process temperature may vary from 40c to 200c or even more in some cases. The terms of ratings and steam pressure, the corresponding requirements are up to 15 tons/hour and 55 bar respectively. This range and diversity of demand placed on its performance has given a fill up to the evolution of its design over the years. While a modern industrial boiler in the shape of a shell type multi-tubular package boiler is an example of optimized design and efficiency, no single design can obviously satisfy the need of such a wide range of requirements.
The textile dyeing and finishing sector uses large volumes of water and substantial quantities of complex chemicals. Companies operating in this sector face lot of challenges, many associated with the acquisition and disposal of these essential raw materials. In particular, the charges incurred for mains water supply and effluent disposal are increasing, and companies need to address these issues to save money and remain competitive in business. Steam is vaporized water, being partly gas, partly liquid. Steam itself is usually interspersed with minute, droplets of water in its liquid state, which gives it a white, cloudy appearance. In industrial and process situations, steam is often generated using water boilers that are heated to create steam under controlled conditions. The energy generated is then transferred and used in many different ways. In nature, steam is produced by the heating of underground water by volcanic processes and is emitted from hot springs, geysers, fumaroles, and certain types of volcanos. Steam is used as a heat transfer medium in several industries like textile, pulp and paper chemical manufacturing to name a few. In the industry, steam is produced by water boilers which come in all shapes, sizes, types and pressures and the water within them likewise. Steam under pressure is at elevated temperatures, greater than 100C and therefore can be used to transfer energy to different parts of a system. This energy can then be used to cook, create energy for chemical reactions, heat water and a myriad of other uses. Steam being "pure" water dissolves other materials into it very easily and it is these other materials that cause problems requiring treatments. The primary function of a boiler is to transfer heat from hot gases generated by the combustion of fuel into water until it becomes hot or turns to steam. The steam or hot water can then be used in building or facility processes.
Except for a small number of specialty models, boilers generally fit into one of the two common categories: fire-tube boilers and water-tube boilers. Fire-tube boilers pass hot combustion gases through tubes submerged in water. Water-tube boilers, on the other hand, circulate water inside the tubes in a closed vessel filled with hot combustion gases. In either category the boiler feed water and fuel often contain impurities, which impairs boiler operation and efficiency. Chemical additives can be used to correct the problems caused by these impurities. To improve feed water quality, fuel oil condition, and steam purity, these chemicals can be injected directly into the feed water, steam or fuel oil.
There are several problems within a boiler system some of
which require chemical treatment or other mechanical means to overcome them.
The major problems are:
- Boiler water carryover
- Sludge Deposition
Preventing scale problems
These can cause problems in all parts of the system starting with the feed tank leading through the boiler and into the condensate system. The problems arise from the quality of the water used within the steam raising system and the manner in which the system is operated and hence it is not only chemical issues that need to be addressed. In extreme cases it has been known for steam boilers to explode causing much damage and even death. So it is for this reason that strict standards have arisen on how to treat and maintain boilers and associated systems. Then there are efficiency problems with excess fuel being used to raise the steam or leaks causing loss of water, chemicals and energy from the system. All of these issues are avoidable with simple chemicals and good maintenance regimes.