Steam Distribution System

With a latent evaporative heat up to 1,000 BTU per pound, very little steam is required to transport a large amount of energy. Other benefits include the safe, non-toxic and non-flammable properties of the steam plus the ability to supply heat at a constant and controlled temperature. Steam can also be supplied to users with conventional pipe and valve equipment that is inexpensive, readily available, requires little maintenance and has a long service life.

If the return pipe is above the boiler water pipe, this is called a dry return. All system highlights require automatic vents to remove non-condensable gases. During operation, steam and condensate flow in the same direction into the electrical network and in the opposite direction into branches and lifts. Steam-based heating systems are common in New York City, especially in pre-war apartments and other old buildings.

Steam systems consist of a steam source, a distribution system and end-use or end-use equipment. Heaters use one or a combination of fuels, including refinery gas, natural gas, fuel and pulverized coal. Refinery gas is collected from process units and combined with natural gas and LPG in a fuel and gas balance drum. The fuel is typically a mixture of direct flow crude refinery oil and cracked waste and other products. The fuel and oil system supplies fuel to process power heaters and steam generators at the required temperatures and pressures. The fuel oil is heated to the pump temperature, is sucked through a thick suction filter, pumped into a temperature control heater and then pumped through a fine mesh filter for combustion.

If the washed water comes into contact with the temperature sensor, it will misread the saturation temperature of the water instead of the actual temperature of the steam, interrupting the control of the system. Because of this interaction, it is recommended to maintain at least 10 ° F overheating as a temperature adjustment point for these applications. A wide variety of clamps are used in steam heating systems and can be widely classified as natural convection units or forced convection units. Natural convection units include well-known “cast iron radiators”, convectors and cabinets.

The installation of a non-return valve is generally not effective in this situation. Retention valves are required if there is a risk of condensate return current. For example, when a trap is drained into a common condensate collection line, there is a potential risk of condensate reflux being drained from other traps, so a non-return valve generally needs to be installed. Preventing this return current is important because it can not only reduce the heating efficiency of the process, but also damage steam traps.

Older versions of the ASHRAE guide showed the use of a diffuser pipe to break through the condensate at high temperature and reduce the size of the vapor bubbles that occur. The guide showed the tangential welding of a tube on the return pipe and drill holes at a distance of at least 1/8 inch 1 inch. Other methods include using a heat exchanger to mix the two temperatures or using fin tube radiation to cool the discharge of the trap. The most commonly used method is to install a flash tank when the leakage trap is discharged, allowing the condensate to flash at 100 ° C (212 ° F) and then pump the cooled condensate to the common return line.

The type of open float or hub, steam trap, where the discharge is controlled by a type of float or bucket, is used to drain condensate from pipes, heaters and other equipment. Steam systems, on the other hand, provide condensation heat with liquid vapor in a heat exchanger at the point of use. Steam condensation releases 2,257 kJ per liter of water , much more than the 83.72 kJ supplied for a liter of chilled water at 20 ° C. This means that almost 30 liters of water must be supplied to provide the same amount of heat as for each liter of condensed steam in a heat exchanger. A steam conditioning system includes lowering the temperature of a desuperheater and reducing pressure.

This spray water control valve must respond quickly to the required travel changes and must be able to close the V-Class when it is closed. In addition, high pressure drop in the water system often requires the valve to contain anti-vitational castings to protect it from damage during operation. Two important applications of steam in the energy and process industry are the performance of mechanical work and as a means of heat transfer.