Second-stage steam pressure

One Ninian stabilization train was commissioned to prove the plant and to provide gas for power and steam generation. Very early in the commissioning operation, however, severe foaming occurred in the second-stage (low-pressure LP ) gas/oil separator, which operated at 0 7 bar gauge [10 Ibf/sq in ], when the temperature of the initial dead-crude feed was raised to 9I4°F ]490°C. As a result, large quantities of crude were carried into ihe flare relief system. 

The second stage of the process is to condition the beads, necessary because on cooling after prefoaming pneumatogen and steam within the cells condense and cause a partial vacuum within the cell. By allowing the beads to stand in air for at least 24 hours air can diffuse into the cells in order that at room temperature the pressure within the cell equilibrates with that outside. 

In subsequent years, Savery made important improvements that benefited future steam inventions. In June 1699 he demonstrated to the Royal Society a pump with two receivers, each with a separate, hand-controlled steam supply. This ensured improved continuity of operation, allowing one receiver tn operate in its vacuum stage and the other under steam pressure. In 1701, he added two more critical steps a second boiler, avoiding the need to shut down the fire and pump, between stages and he replaced the two interconnected steam cocks with a single valve, run with a manually operated long lever. This may have been the inspiration for the modern slide valve and his inventiveness created, in effect, the world s first feed-water heater. 

At the vapor outlet of the first-stage cyclones, an opening allows entry of stripping steam/vapors and reactor dome steam. This opening is sized to allow the second stage cyclones to be operated at a negative pressure relevant to the reactor housing pressure. 

The balance of the DO is not readily released to the steam and is removed by a second stage in the DA. This stage is a gas scrubbing stage, and the specific mechanics vary with each of the different types of pressure DA. 

The urea-product solution, leaving the first decomposition stage and still containing some unreacted carbamate and excess NH3, is let down in pressure and steam heated in the second-staged decomposition section, which operates at about 2 atm and 120°C. Practically all of the residual carbamate is decomposed and stripped from the urea-product solution together with the residual excess ammonia. The 74—75 wt % urea solution thus obtained is further processed to solid urea... 

Ninian Stabilization, Cold Ninian unstahilized crude at 26 bar gauge 377 lbfisq in is healed in three stages first by exchange of heat with hot stabilized crude second, with steam condensate, and third, with medium-pressure steam. The hot, unstabdiz.cd crude then enters... 

UHT milk differs from pasteurized milk mainly in the heat treatment employed for sterilization. Usually UHT milk is heated at 130° to 150°C for 2 to 8 seconds and is then aseptically packaged. In the final heating stage, steam is injected directly into the milk, or the milk is infused into a steam chamber, followed by flash evaporation to remove added water (steam). An alternative procedure, the indirect method, involves heating milk across a stainless steel barrier, using high-pressure steam as the heating medium (Mehta 1980). 

The overhead from the second stage is heated by an exchange with hot solvent. The fired heater further raises the temperature of the solvent/demetallized oil mixture to a point above the critical temperature of the solvent. This causes the demetallized oil to separate. It is then flashed and steam-stripped to remove all traces of solvent. The vapor streams from the demetallized oil and asphalt strippers are condensed, dewatered, and pumped up to process pressure for recycle. The bulk of the solvent goes overhead in the supercritical separator. This hot solvent stream is then effectively used for process heat exchange. The subcritical solvent recovery techniques, including multiple effect systems, allow much less heat recovery. Most of the low grade heat in the solvent vapors from the subcritical flash vaporization must be released to the atmosphere requiring additional heat input to the process. 

In extraction turbines, in addition to the governor valve, a second "valve" is required (Figure 2.134), which controls the steam flow rate that is extracted from the first stage of the turbine and is sent to the second stage. The extraction rate can be controlled either to keep the shaft speed or the pressure of the LP header constant, or a combination of the two. If the turbine incorporates the controls as a built-in feature, the turbine is referred to as an "automatic-extraction" type. Such turbines are generally designed to deliver 100% shaft power and to provide extraction steam only if the load requirements permit. This is the most common type of extraction machine. 

An intriguing aspect of this control configuration is the possibility of completely eliminating the need to throttle steam if the turbine capacity is sufficient to meet the demand for LPS. In that case the supply valve is kept fully open, as was the case in Figure 2.133, and the pressure controls of the LPS header determine the distribution of the extracted steam between the turbine s second stage and the LPS header. 

ILPM [Improved Low-Pressure Methanol] A process for making methanol from natural gas, which has two stages. The first stage converts the gas to CRG. The second stage converts this gas to methanol in a Kvaemer Steam Raising Reactor. Developed by Kvaerner Process Technology in 2000, and proposed for use in Germany from 2003. 

This two-stage deaeration enables the temperature of the steam-boiler feedwater, which comes from the second-stage deaerator, to be held constant. The feedwater boiling point depends on the pressure of the steam fed to the deaerator. 

Figure E5.8 is a hypothetical process used for demonstration by Diamond Shamrock Co. of their flowsheeting code PROVES. Makeup gas is compressed, combined with recycle gas, and fed, together with liquid raw material, into a three-phase, suspended bed catalytic reactor. The reactor is cooled by recirculating liquid through a heat reclamation steam generator. Reaction products are condensed and the pressure of the exit stream reduced in two stages. The gas from the first-stage separator is recirculated, whereas the liquid from the second-stage separator is fed into a distillation column. Pure product is withdrawn from the bottom of the column. The distillate is a by-product that is pumped to another plant.

Purification of these oxidation products of cyclohexane for the second-stage nitric acid oxidation to adipic acid is not necessary but is advantageous from the viewpoint of yield and purity of product. The preferred commercial practice is to treat the product obtained by air oxidation of ( cldhexane in pressure autoclaves with a controlled amount of water to permit an oil-water separation. The cyclohexanol and cyclohexanone dissolved in the water phase are removed by steam distillation and added to the oil phase. Succinic and glutaric acids which occur as by-products are recovered from the water phase. The combined oil is stripped to remove dissolved cyclohexane for recycle to the stage 1 air oxidation. The oil is then steam distilled and freed of water. ... 

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