Water Seal

Specific Teasile Elongation, Heat-seal Water-vapor Gas... 

Control of an evaporator requires more than proper instrumentation. Operator logs snould reflect changes in basic characteristics, as by use of pseuao heat-transfer coefficients, which can detect obstructions to heat flow, hence to capacity. These are merely the ratio of any convenient measure of heat flow to the temperature drop across each effect. Dilution by wash and seal water should be monitored since it absorbs evaporative capacity. Detailed tests, routine measurements, and operating problems are covered more fuUy in Testing Procedure for Evaporators (loc. cit.) and by Standiford [Chem. Eng. Prog., 58(11), 80 (1962)]. 

Repair. Repairs for damaged bonded structure can be either mechanical or adhesively bonded. Mechanical repairs are metallic doublers on one or both sides of a damaged component, held on by fasteners. The fasteners transfer the load through the doubler around the damaged site and restore part functionality. Although common for metal-to-metal bonded structure, mechanical repair of sandwich structure is rare because of the risk of further delamination. Unless the doubler and fasteners are perfectly sealed, water can travel into the honeycomb core eventually causing freeze-thaw damage and delamination. 

Safe disposal of the effluent seal water, considering possible contamination by process fluids. 

Flare system designs must also include means of preventing freezing of seal water in the flare seal drum, if entering vapors may be below 0°C. 

It is important to note that even if the blowdown is effective in disengaging liquid and vapor, further condensation could occur downstream especially if the vented vapor exits the drum at a temperature above ambient conditions. A proportion of such condensible materials in the blowdown drum vapor release may condense as a result of cooling in the flare header and contact with seal water, and then disengage in the flare seal drum while condensible vapors which are not condensed out at this stage may condense in the flare stack or its inlet line, thus creating the potential for hazardous fallout of burning liquid from the flare. Condensed hydrocarbon in the seal drum can be entrained out with the... 

Provide settling facilities to separate hydrocarbon liquid from the flare seal water effluent, and appropriate means of disposal, e.g., to slop storage. 

Valves in the inlet, seal water and pilot gas lines should be located according to permissible radiant heat densities for personnel (refer to the last section of this chapter for specific guidelines). Piping to the burning pit should be suitably protected against flame impingement (e.g., by installation below grade). 

The drum is usually equipped with steam injection if required for winterizing or cold releases. Refer to Figure 7 for some of the details. If winterizing is necessary, then the steam should be temperature-controlled in order to maintain the seal water temperature at 4 to 10 C. It is important to note that the drum should be located at a minimum safe distance from the flare. 

A secondary seal loop is provided for water withdrawal during major blows when turbulence at the downstream overflow connection to the primary seal loop interferes with normal drainage. Extending the base of the flare stack 3 diameters below the sloped inlet line provides vapor disengaging for the secondary seal leg. The bottom of the stack and inlet line up to 1.5 m above the seal water level are gunite lined for corrosion protection. 

Disposal of Seal Water - Effluent water from water seals must be routed to safe means of disposal, considering possible hazards arising from liquid or vapor hydrocarbons or toxic materials that may be entrained or dissolved in the water. Seal water should be discharged as follows ... 

If HjS is never present in the flare gas, seal water effluent should be routed through an open fuimel (to permit checking of seal water flow) to a manhole in a vented section of the oily water sewer. The water inlet to the manhole must be sealed. 

However, pollution considerations may make the routing of seal water to the sewer unacceptable, in which case disposal must follow method (3) below. 

If HjS is continuously present in the flare gas or if the flare seal drum also functions as a sour water disengaging drum, then the effluent seal water must be routed to a sour water stripper, desalter, or other safe means of disposal. Withdrawal from the drum is by pump in place of the normal loop seal arrangement. Two pumps are provided one motor driven for normal use, and the other having a steam turbine drive with low pressure cut-in. The seal drum level is controlled by LIC with high and low alarm lights plus an independent high level alarm. 

In categories (1) and (2), the manhole receiving effluent seal water should be located at least 15 m from the windbreaker. 

Flashback protection is required for H2S flaring systems, either by water seal or continuous gas purge. If a water seal is used, special requirements apply to the disposal of the effluent seal water. In the case of an HjS flaring system handling a flow of HjS which in uninterrupted throughout the period that a plant is in operation, and which stops only when the producing plant is shutdown, then flashback protection is not required. However, steam or inert gas connections are required to permit purging the flare line startup and shutdown. 

Flare systems must be protected against any possibility of partial or complete blockage by ice, hydrates, solidification, etc. Seal Drums and Y-seals requiring winterizing should be provided with temperature-controlled steam injection to maintain the seal water temperature at 4 to 10 C. This limits the quantity of water vapor entering the flare stack. 

The common theme of many of these items is that blowdown lines and flare and vent stacks should be kept simple because they are part of the pressure relief system. Avoid flame arrestors, molecular seals, water seals, and U-bends. Avoid steam, which brings with it laist and scale and may freeze. 

Sperr-klmke, /. catch, pawl, ratchet, detent, -kreis, m. block circuit, wave trap circuit, -metail, n. ply metal, -rad, n. ratchet wheel, cog wheel, -schichtenzelle, /. solid photovoltaic cell, -ung, /. shutting, etc. (see sperren). -ventil, n. stop valve, check valve, shut-off valve, -waffe, /. defensive weapon, -wasser, n. sealing water. 

Figure 6-37. Typical capacity performance curve for a process liquid ring vacuum pump. Note that the vacuum is expressed here as gauge, referenced to a 30" Hg barometer, when 60°F seal water is used. For higher temperature water, the vacuum will not be as great. By permission, Nash Engineenng Co.

SEALING WATER SUPPLY press. temp. flow 11... 

Sample Preparation. Liquid crystalline phases, i.e. cubic and lamellar phases, were prepared by weighing the components in stoppered test tubes or into glass ampoules (which were flame-sealed). Water soluble substances were added to the system as water solutions. The hydrophobic substances were dissolved in ethanol together with MO, and the ethanol was then removed under reduced pressure. The mixing of water and MO solutions were made at about 40 C, by adding the MO solution dropwise. The samples for the in vivo study were made under aseptic conditions. The tubes and ampoules were allowed to equilibrate for typically five days in the dark at room temperature. The phases formed were examined by visual inspection using crossed polarizers. The compositions for all the samples used in this work are given in Tables II and III. 

Used industrially for the manufacture of pure silicon, silane, and fluosilicic acid used to seal water out of oil wells during drillings. 

Heavy (11 weeks) Black liquor Firing weak liquor liquor diluted from pump sealing water... 

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