Steam condensate removal

Steam condensate removal is most commonly achieved by traps—devices that, in efFea, are very simple level controllers. Many plants have experienced the need for high maintenance with these. Sometimes enough steam leaks through to impair the accuracy of steam-consumption estimates based on steam flow metering. In addition, as pointed out by Mathur, a rapid closure of the steam valve may cause a vacuum in the shell and pull back condensate through the trap with possible hammering and vibration in the shell. As a result, some reboilers, particularly large ones, are now equipped with condensate seal pots. These pots then have conventional level controllers. 

During this process some water will have condensed in the steam-trap D and also in the distillation bulb F. If at the end of the steaming-out process, the Bunsen burner is removed from the generator A, the pressure in A will be reduced owing to steam condensation, and the liquid in F will be sucked back into D provided that the benL-over tube is carefully adjusted, the bulb F may be almost completely emptied of liquid as desired. Finally the condensed water in the steam-trap D may be run out by op ing the tap Tj. 

Condensate Polishing. Ion exchange can be used to purify or poHsh returned condensate, removing corrosion products that could cause harmful deposits in boilers. Typically, the contaminants in the condensate system are particulate iron and copper. Low levels of other contaminants may enter the system through condenser and pump seal leaks or carryover of boiler water into the steam. Condensate poHshers filter out the particulates and remove soluble contaminants by ion exchange. 

Condensation is the process of reduction of matter into a denser form, as in the liquefaction of vapor or steam. Condensation is the result of the reduction of temperature by the removal of the latent heat of evaporation. The removal of heat shrinks the volume of the vapor and decreases the velocity of, and the distance between, molecules. The process can also be thought of as a reaction involving the union of atoms in molecules. The process often leads to the elimination of a simple molecule to form a new and more complex compound. 

Petrochemical Recycling of steam condensate for boiler feed water Removal of oil and hydrocarbon contamination... 

Figure 3-44. Surface condenser condensate removal. Closed system steam surface condenser NPSH requirements. (By permission, Cameron Hydraulic Data, 16th ed. ingersoil-Rand Co., 1979, p. 1-12.)...

An evaporator operating on the thermo-recompression principle employs a steam ejector to maintain atmospheric pressure over the boiling liquid. The ejector uses 0.14 kg/s of steam at 650 kN/m2, and is superheated by 100 K and the pressure in the steam chest is 205 kN/m2. A condenser removes surplus vapour from the atmospheric pressure line. What is the capacity and economy of the system and how could the economy be improved ... 

The rinse water, steam/condensate, and residual agent bypass the AQS and go to the agent collection system. After the agent is removed from the warhead and the warhead has been steamed out, the rocket is rotated 90 degrees to minimize agent leakage from the punch holes. 

The process produces some organic waste derived from the thermal breakdown products of the wood, which is dealt with in a biological treatment facility. Volatile by-products are removed in a scrubber associated with a steam-condensing unit. Energy consumption is 2.8MJ to produce 1 kg of modified wood and the cost of production is about 150 Euros per m, with operational costs of 20 Euros per m. A plant capable of an annual production capacity of 75 000 m would require an initial investment of some 10-15 million Euros. 

The CleanSoil process is an ex situ treatment technology that uses steam to remove hydrocarbons and chlorinated solvents from contaminated soils. The steam vaporizes the contaminants from the soil and carries them to a condenser for recovery. The water is converted back into steam and reused in the system. The remaining vapors pass through an activated carbon filter and are released into the atmosphere. The technology has been applied full-scale at multiple sites and is commercially available. 

HPO uses dynamic underground stripping (DUS) technology to inject steam and oxygen into the subsurface. When injection stops, the steam condenses, and contaminated groundwater returns to the heated zone. Chlorinated contaminants in the groundwater mix with the oxygen and condensate and, with the presence of heat, rapidly oxidize into carbon dioxide and chloride. HPO is able to destroy the residual DNAPL components not readily removed by the DUS process. 

In a short period, usually less than a minute, the balloon will be pushed into the bottle similar to the egg being pushed into the bottle. In this case, the baby bottle fills with water vapor when it is boiling. When the bottle is removed from the oven, it is filled with steam and it immediately begins to cool. Quickly placing the lid on the bottle traps the steam. As the bottle continues to cool, the steam condenses. This decreases the pressure inside the bottle, and the balloon is forced into it. The same principle is used to seal jars when making jelly or canning. 

In most properly operated process plants, most of the boiler feedwater should be recovered condensate, that is, when steam condenses to water, the condensate produced should be recovered and returned to the boiler house. Often, the recovered condensate will first pass through a deoiling clay bed, to remove any hydrocarbon contaminants. To calculate the percent of condensate recovered, we need to know two numbers ... 

Finally, the steam turbine s buckets can foul with hardness deposits from the steam. This reduces the turbine efficiency, and may prevent a pump from running at its rated speed. Injecting steam condensate into the steam supply can remove such deposits. 

Figure 3.9. Steam heaters, (a) Flow of steam is controlled off the PF outlet temperature, and condensate is removed with a steam trap or under liquid level control. Subject to difficulties when condensation pressure is below atmospheric, (b) Temperature control on the condensate removal has the effect of varying the amount of flooding of the heat transfer surface and hence the rate of condensation. Because the flow of condensate through the valve is relatively slow, this mode of control is sluggish compared with (a). However, the liquid valve is cheaper than the vapor one. (c) Bypass of process fluid around the exchanger. The condensing pressure is maintained above atmospheric so that the trap can discharge freely, (d) Cascade control. The steam pressure responds quickly to upsets in steam supply conditions. The more sluggish PF temperature is used to adjust the pressure so as to maintain the proper rate of heat transfer.

In most cases, condensate does not require treatment prior to reuse. Makeup water is added directly to the condensate to form boiler feedwater. In some cases, however, especially where steam is used in industrial processes, the steam condensate is contaminated by corrosion products or by the inleakage of cooling water or substances used in the process. Hence steps must be taken to reduce corrosion or to remove the undesirable substances before the condensate is recycled to the boiler as feedwater. 

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