Steam Usage Principles
An Introduction to Industrial Steam Usage.
Steam is an extremely versatile and useful source of energy used in various industries, and has many pro's versus other energy sources.
Why use steam?
Heat produced by steam can be accurately moderated by controlling the pressure, and is capable of transferring much energy with little effort. In addition, steam contains no toxins and is not flammable, making it ideal for industrial purposes. Incorrect utilization can result in poor performance and wasted energy, however, understanding of basic principles of steam can readily provide significant efficiency.
The boiler is the core of a steam cycle, heating water to create steam. Boilers are usually installed centrally, and supply the needs of the plant at the optimal pressure required, within the design specification. Boiler corrosion is not uncommon, but easily overcome with a properly managed blowdown procedure. This is required to prevent salt deposits and sludge from becoming too dense. One or more separators are generally installed in the distribution line to remove water droplets and ensure that the steam is dry.
The piping that transports the steam from the core to the relevant equipment is known as the Distribution System. Energy loss prevention in the distribution system is essential, and hence the piping must be properly insulated. Steam traps are an important part of this system in order to promote good drainage.
Pressure Reducing Stations
The steam pressure is distributed at the highest possible by the available boilers to minimize pipe sizes. This pressure may occasionally need to be reduced, as most steam equipment operate at varying temperatures, and consequently different pressures. A pressure reducing station is used in these cases, and ensure the correct pressure is supplied to the equipment. Pressure reducing station may include pressure relief valves and water separators to prevent damage and assure dry steam is supplied.
Control valves are used to regulate the heat transfer, which occurs within the equipment. Energy supplied and heat transfer rate are prone to numerous elements, including: steam pressure, transfer material, and particles in the air.
Science teaches us that when steam cools, it condenses into water. This holds true in a steam system, and must be swiftly and efficiently removed in order to retain latent energy and prevent heat transfer rate reduction. Gravity, aided by equipment steam pressure, is the simplest manner in which to drain the condensate. Steam traps and utilized to drain the condensate.
Condensate retains valuable heat energy and chemical purification, and it is advisable to not waste this high quality product. Usually this resource is recovered by pumping the drained condensate back to the boiler to that it my be reused. Doing so lowers overall loss, as the recovered condensate is already treated and distilled, which in turn prevents corrosion in the system.
High temperature condensate my spontaneously convert into steam if the pressure imposed on it is suddenly reduced. This is known as 'flash steam', or 'flashing', and occurs most often after steam traps. Flash steam can be separated from the condensate, and if reused can help save energy.