Process Boilers
Overview
A Process boiler is a type of boiler with a capacity (rated maximum input) of 90KW or more, derves a process. A process is an activity or treatment that is not related to the space conditioning, service water heating, or ventilation of a building as it relates to human occupancy.
Process Boilers used in various Industries
Process boilers are used in various industries such as dairy, sugarcane, pulp & paper, chemical, beverages and textile industries also in thermal power station etc. Process boilers are having application in following areas:
● Agriculture
● Animal food
● Industry Automotive
● Industry Bakeries
●Ceramic industry
● Cheese and dairies
● Distilleries
● Electrical industry
● Food packaging industry
● Fruit processing
● Glass fiber production
● Metal-working industry
● Pharmaceutical industry
● Dyeing factories
● Refineries
● Spinning mills
● Tobacco industry
● Tyre manufacturing
● Weaving mills
● Wood processing
● Plastics
● Manufacturing
Working of Process Boiler
Basic features of process boiler. A process boiler system is a hot water steam boiler operated with a certain kind of fuel. The boiler heats up or evaporates the water inside it, which is then transported to the consumers via pipe systems. In case of hot water the transport energy is generated by pumps, in case of steam the transport is based on inherent pressure. The cooled water or the condensed steam returns to the boiler where it can be heated again Loss of water is compensated by makeup water pump. Flue gases created by combustion are discharged into the atmosphere through a chimney. In process boilers steam generation capacity ranges from 175 kg/h to 55 000 kg/h are available for industrial applications. High-quality equipment with intelligent control systems, modern burner technology and efficient heat recovery devices ensure environmentally friendly, economic and fully automatic boiler operation. These boilers are welded from thick steel plates that are up to 35 mm thick, making pressures of 30 bar and more possible. A thermal output of up to 38 MW is possible from a single boiler.
The use of process boiler systems in practice.
Food industry
Food must often be heated or boiled during processing. Thus this industrial sector obviously needs plenty of thermal energy. However, some steam applications are still stunning a good example is potato processing.
Cold potatoes are filled in a big pressure vessel and hot steam is abruptly injected. The abrupt heat supply causes the potato peels to fall off so they do not have to be peeled by hand any more
Breweries
In complex production process of breweries, malt has to be ground coarsely and mixed with water. The brewer calls this mashing. The mash must be heated to various temperatures in two to four hours for which the steam previously generated with the steam boiler is used.Subsequently, hops are added and the mixture has to cool down. Then yeast is added and triggers the fermentation so that the breweries get the desired effect. Depending on the type the breweries still has to mature for up to three months until it can be filled in bottles or barrels.
Dairy
Process Boilers are mostly used in dairy industry for milk pasteurization and UHT. Milk Boiler ensures good shelf life and destroys disease-causing microorganisms. This emphasizes the requirement for flexible and reliable heat sources, which may keep the dairy milk systems running without any hurdle. Dairy Industry use steam for various purposes. Such as Heat Treatment of dairy products & Dairy Processing
Industrial milk boiler used to generate steam for following processes in dairy Industry
(1) Milk powder
(2) Cheese
(3) Liquid milk pasteurization
(4) Ultra-heat treatment (UHT) Milk
Sagar Industry
Electricity and steam are almost required in every step of raw sugar process, especially in juice extraction, clarification, evaporation and sugar drying, good quality steam takes a crucial role. Thus selection of steam boilers becomes very important for sugar plant.
Bagasse, nearly 30% fiber contained in sugar cane, is produced during the processing of sugarcane, is burned as fuel for the generation of steam and power required for the operation of sugar mill. In fact, most cane sugar factories have been designed to be energy self sufficient, with sugar as the primary product and bagasse as the primary fuel.
A bagasse-fired cogeneration system, made of steam boilers and steam driven turbo alternators, provides all the steam and electricity needed to run the cane mills and factory, leaving little surplus bagasse. The bagasse is fired in the boiler for producing steam at high pressure, which is extracted through various single high capacity turbines and used in the process.
The installation of high pressure boilers and high pressure turbo-generators has provision for the operation of co-generation plant during the off-season also that enhances the power generation from 9 MW to 23 MW.
Paper & Pulp Industry
Boilers in the paper industry are used to generate steam for power and process systems. High pressure steam is generated for steam turbine generator sets to produce electric power Medium and low pressure steam is used for various process heating applications such as heating and softening pulp wood chips for further reduction by chemicals to make wood pulp. Steam is also used to heat chemicals and other processes. In the paper making process, steam is used to evaporate moisture from pulp and to heat rotating dryer drums to dry the paper stock. Depending on the location and type of pulp wood used, bark chips can be burned as fuel for boilers.
Steam condensate
Condensate is the liquid formed when steam passes from the vapor to the liquid state. In a heating process, condensate is the result of steam transferring a portion of its heat energy, known as latent heat, to the product, line, or equipment being heated.
Difference between steam and condensate?
Flash steam is released from hot condensate when its pressure is reduced Because both types of steam are produced in the boiler, it is impossible to differentiate between them. Only when flashing takes place at relatively low pressure, such as at the discharge side of steam traps, is the term flash steam widely used.
Steam Loop
An arrangement of pipes by which water of condensation can be returned to the boiler without a pump or injector as a result of condensation of boiler steam in a loop of two vertical pipes connected by a horizontal one
Steam Trap
A steam trap is a valve designed to sense the difference between steam and condensate, and drain the condensate from the line. Steam traps allow only condensate and gases to drain and "traps" the steam in to provide heat and power
Working of Steam Trap
In industrial and commercial facilities and plants, as well as the marine industry, steam is still used commonly as a source of energy--for heating processing, and power. Steam traps are used anywhere there is a steam-powered system to discharge condensate, that is, the liquid that builds up in the pipelines, along with other non-condensable gases, to relieve the pressure in the lines and regulate the flow of steam within in it. To do this effectively, steam traps are placed at intervals along the pipelines.
A steam trap is a valve designed to sense the difference between steam and condensate, and drain the condensate from the line Steam traps allow only condensate and gases to drain and traps" the steam in to provide heat and power Too much condensate will lead to a buildup in pressure, causing hammering inside the pipeline, blown seals, work stoppages, etc. A proper functioning steam trap removes condensate and non-condensable gases without losing any live steam. Figure shows cross sectional view of steam trap.
Types of STEAM TRAPS
Depending on the methods the steam trap uses to differentiate between steam and the condensate, steam traps can be divided into 4 different types
1. Mechanical
2. Temperature
3. Thermodynamic
4. Venturi nozzle
