Open steam stripping

Example 8-20 Open Steam Stripping of Heavy Absorber Rich Oil of Li t Hydrocarbon Content (used by permission following the method of R. W. EUerbee, Chemical Engineering [127])... 

Figure 8-41. Open steam stripping light hydrocarbons from a rich oil. Modified for Example 8-20 and used by pemnission, Ellerbee, R. W., C/iem. Eng. Mar. 4 (1974), p. 108.

Batch with Constant Reflux Ratio, 48 Batch with Variable Reflux Rate Rectification, 50 Example 8-14 Batch Distillation, Constant Reflux Following the Procedure of Block, 51 Example 8-15 Vapor Boil-up Rate for Fixed Trays, 53 Example 8-16 Binary Batch Differential Distillation, 54 Example 8-17 Multicomponent Batch Distillation, 55 Steam Distillation, 57 Example 8-18 Multicomponent Steam Flash, 59 Example 8-18 Continuous Steam Flash Separation Process — Separation of Non-Volatile Component from Organics, 61 Example 8-20 Open Steam Stripping of Heavy Absorber Rich Oil of Light Hydrocarbon Content, 62 Distillation with Heat Balance,... 

Many refineries now use vacuum pumps and surface condensers in place of barometric condensers to eliminate generation of the wastewater stream and reduce energy consumption. Reboiled side-stripping towers rather than open steam stripping can also be utilized on the atmospheric tower to reduce the quantity of sour-water condensate. 

C. Vacuum Dechlorination. Section 7.S.9.2 discussed three approaches to dechlorination. Open steam stripping applies primarily to waste water rather than brine and therefore appears more commonly in diaphragm-cell plants. Air stripping, while applied on scales up to 100 tpd of chlorine, is normally associated with small plants. Figure 11.15 assumes the use of vacuum dechlorination. Acidified dechlorinated brine is fed to a packed stripping column, shown here as mounted on a receiver. 

A gas processing plant selectively extracts ethylene and ethane from an incoming natural gas mixture stream. These two light hydrocarbons are absorbed in a heavy gasoline type absorber oil, and then stripped with open steam in an open tower. The system data are (see Figure 8-41) ... 

I was once working in a refinery that could not meet the flash-point specification for its diesel product. Flash point is the temperature at which a hydrocarbon will ignite, when exposed to an open flame. To raise the flash point of diesel oil, it is steam-stripped, to remove the lighter, more combustible components. I noticed that I could drain water from the bottom of the steam supply line to the diesel-oil stripper. I then screwed a steam trap, on to the i/4-in drain valve, on the steam supply line. The stripper bottoms temperature increased by 35°F, and the flash temperature of the diesel product increased from 120 to 175°F,... 

K-Resin SBC was invented by Alonzo Kitchen, a research chemist at Phillips Petroleum Research and Development laboratories. With inventorship came the opportunity to name the new resin, which he called K-Resin . The first pilot plant resins were made in 1967, and commercial samples were prepared for test marketing in 1968. Commercial production started in October of 1972 at the SBC plant in Borger, Texas, on a 10 million pound per year capacity line. Initially, the solution product was steam stripped to remove the hydrocarbon solvent, but this left a significant haze in the resin. The finishing system was quickly converted to a devolatilizing extruder. Commercial production continued at this plant until 1979, ending with the opening of a new production facility at Adams Terminal (later renamed the Houston Chemical Complex) in Pasadena, Texas. The new plant had a nameplate capacity of 120 million pounds per year. Plant expansions increased the production capacity in 1988 and 1994 to a total nameplate capacity around 300 million pounds per year. 

All heat requirements for the process are provided in the form of open steam at 400 psia. Some is used at the bottom of S-1 to strip HjS and the rest is fed to the twelfth plate in HT-1 to control the temperature of the hot towers and to compensate for heat losses and heat exchanger inefficiencies. Steam consumption is 1778/0.28 = 6400 mol/mol of DjO produced. This is much less than the 200,000 mol/mol DjO needed in water distillation. Additional energy in the amount of 680 kWh/kg D2O is used to circulate gas and pump liquid. This, however, is much less than is used in electrolysis or hydrogen distillation (Table 13.7). The low energy consumption of the GS process is due in large measure to the efficient heat recovery obtainable in the flow sheet Fig. 13.30, which follows Spevack s patent [S7]. 

The feed is partially vaporized 2278 lb mol/h of vapor with a feed of 3644 lb mol/h. It is introduced into the flash zone on Stage 22. There are three stages below the flash zone that are used to strip out any light material that is in the liquid leaving the flash zone. Open steam is fed to the bottom of the column at a rate of 12,000 Ib/h. The bottoms stream from the pipestill ( reduced crude ) goes to a downstream vacuum pipestill in which more gas oil is recovered. The low pressure in the vacuum furnace produces more vapor for the same furnace temperature. 

The reflux ratio is 3.71. At Stage 6, some liquid is withdrawn and fed to a 4-stage stripper. Open steam (3300 Ib/h) is used to strip light material from the liquid leaving the main column. A kerosene product is produced from the bottom of the stripper. It has ASTM 5% and 95% boiling points of 396 and 502 F, respectively. 

Effect of Changing Stripping Steam. Open steam is used in the strippers to remove the light material that is in the liquid withdrawn from the main column. Changing stripping steam flow rate affects the initial part of the boiling point curve, but has less of an effect on 5% point and essentially no effect on the 95% point and product flow rates. Of course, using more steam increases steam consumption and increases the load on water purification facilities required to handle the water decanted off the reflux dmm. 

Similarly, an equation of the same sort applies to the stripping of the mercaptans in the regeneration step. For each mercaptan, and for open steam injection into the stripper,... 

Open steam is not used to strip chlorine from brine, where the dilution it would cause is objectionable. Its application is limited to chlorine-bearing condensate, and it is therefore discussed in the Section 9.1.3.5B on chlorine cooling. 

An acetone-water solution (5 percent by weight of acetone) is stripped by open steam in a column. The Lm/Gm ratio is 19. The Henry s Law relation is T = 36.9X. Also, the relation between X s in equilibrium with Y are... 

As an example of using open steam to obtain a steam distillation, consider the steam stripping of an oil containing 2.54 mol per cent propane at 20 p.s.i. 

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