Two-stage jet system

For a surface condenser to work properly, noncondensable vapors must be sucked out of llie shell side. This is done with a two-stage jet system, as shown in Fig. 18.3. When I was first commissioned the jets, they were unable to pull a good vacuum. Moreover, water periodically blew out of the atmospheric vent. I found, after considerable investigation, that the condensate drain line from the final condenser was plugged. 

In Chap. 23 we reviewed several problems pertaining to steam jet precondenser and intercondenser problems. The surface condensers, which serve condensing steam turbines, are subject to all the same problems and a lot more. A standard surface condenser package with an associated two-stage jet system is shown in Fig. 25.3. By way of summarizing many of the problems that occur with this sort of equipment, I will relate my trials and tribulations with K-805, an auxiliary combustion air blower at the Good Hope Refinery in Norco, Louisiana (now Valero). 

The particle beam system is a simple transport device, very similar to a two-stage jet separator. The solvent vapour is pumped away, while the analyte particles are concentrated in a beam and allowed to enter the mass spectrometric source. Here they are vapourized and ionized by electron impact. 

A two-stage steam jet is to be used on a large vacuum system. It is estimated that 9 kg of air must be removed from the system per hour. The leaving vapors will contain water vapor at a pressure equivalent to the equilibrium vapor pressure of water at 15°C. If a suction pressure of 2.0 in. Hg absolute is to be maintained by the jet, estimate the pounds of steam required per hour to operate the jet. 

The Jet Propulsion Laboratory (JPL) Process (20) has also been the subject of study. This process is a two-stage countercurrent adsorption system using PAC. Fresh activated carbon is mixed with wastewater in the secondary mixing basin and settled, and then the entire mixture of settled sewage solids and activated carbon is transferred to the primary mixing basin. Settled solids and carbon are removed from the primary settling basin, dewatered, and transferred to a pyrolysis reactor. The reactor produces activated carbon, which is then recycled to the secondary mixing basin. 

Noncondensable gas-removal system, to remove and compress the noncondensable gases. A typical system uses two stages of compression. The first stage is a steam jet ejector. The second stage is another steam jet ejector, a liquid ring vacuum pump, or a centrifugal compressor. 

Heuristic 46 For pressures down to 10 torr and gas flow rates up to 10,000ft /min at the inlet to the vacuum system, use a liquid-ring vacuum pump. For pressures down to 2 torr and gas flow rates up to 1,000,000 ft /min at the inlet to the vacuum system, use a steam-jet ejector system (one-stage for 100 to 760 torr, two-stage for 15 to 100 torr, and three-stage for 2 to 15 torr). Include a direct-contact condenser between stages. 

The VKR-MT nuclear steam supply system uses a direct cycle vessel-type boiling water reactor, which includes (see Fig. X-10 and X-11) (a) The reactor vessel (b) The reactor vessel cover (c) An internal metallic shaft (d) The core (e) Two stages of the centrifugal separators (f) The block of protective tubes (g) Radiation and thermal shielding of the reactor vessel (h) The supporting structure (i) Jet pumps (j) Control rod drives (k) The reloading system for micro fuel elements. 

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