Stripper activities

The second Hquefaction process is carried out at temperatures from 261 to 296 K, with Hquefaction pressures of about 1600—2400 kPa (16—24 atm). The compressed gas is precooled to 277 to 300 K, water and entrained oil are separated, and the gas is then dehydrated ia an activated alumina, bauxite, or siHca gel drier, and flows to a refrigerant-cooled condenser (see Drying agents). The Hquid is then distilled ia a stripper column to remove noncombustible impurities. Liquid carbon dioxide is stored and transported at ambient temperature ia cylinders containing up to 22.7 kg. Larger quantities are stored ia refrigerated iasulated tanks maintained at 255 K and 2070 kPa (20 atm), and transported ia iasulated tank tmcks and tank rail cars. 

A flow diagram for the system is shown in Figure 5. Feed gas is dried, and ammonia and sulfur compounds are removed to prevent the irreversible buildup of insoluble salts in the system. Water and soHds formed by trace ammonia and sulfur compounds are removed in the solvent maintenance section (96). The pretreated carbon monoxide feed gas enters the absorber where it is selectively absorbed by a countercurrent flow of solvent to form a carbon monoxide complex with the active copper salt. The carbon monoxide-rich solution flows from the bottom of the absorber to a flash vessel where physically absorbed gas species such as hydrogen, nitrogen, and methane are removed. The solution is then sent to the stripper where the carbon monoxide is released from the complex by heating and pressure reduction to about 0.15 MPa (1.5 atm). The solvent is stripped of residual carbon monoxide, heat-exchanged with the stripper feed, and pumped to the top of the absorber to complete the cycle. 

The overhead temperatures of both the absorber and stripper are kept as low as possible to minimise solvent carryover. A temperature of about 311 K is typically used ia the high pressure absorber. The overhead temperature ia the stripper is set by the boiling poiat of the saturated complex solution and by the operating pressure of the stripper. At a stripping pressure of 0.166 MPa (1.7 atm), a temperature of 378 Kis used. The solvent-rich gas from the stripper is cooled to recover as much solvent as possible by condensation prior to the final aromatics-recovery section. Fiaal solvent recovery is accomphshed by adsorption on activated carbon (95). 

Three major sources in the kraft process are responsible for the majority of the H2S emissions. These involve the gaseous waste streams leaving the recovery furnace, the evaporator and the air stripper, respectively denoted by R), R2 and R3. Stream data for the gaseous wastes are summarized in Table 8.8. Several candidate MSAs are screened. These include three process MSAs and three external MSAs. The process MSAs are the white, the green and the black liquors (referred to as Si, S2 and S3, respectively). The external MSAs include diethanolamine (DBA), S4. activated carbon, Sj, and 30 wt% hot potassium carbonate solution, S6. Stream data for the MSAs is summarized in Table 8.9. Syndiesize a MOC REAMEN that can accomplish the desulfurization task for the three waste streams. 

Several proprietary processes have been developed based on the hot carbonate system with an activator or catalyst. These activators increase the performance of the hot PC system by increasing the reaction rates both in the absorber and the stripper. In general, these processes also... 

Collection of the phosphate-stripped activated sludge, which has extremely high phosphorus uptake capacity from the stripper. 

Air strippers are ex situ devices used to physically transfer volatile organic contaminants (VOCs) from groundwater, surface water, or wastewater to air. Contaminants are not destroyed by air stripping, but once they are transferred to the airstream, they may be destroyed by oxidation or incineration, or removed using activated carbon absorption. 

ShallowTray air strippers are low-profile, transportable units for removal of volatile contaminants from aqueous waste streams and potable water supplies. Air strippers do not destroy contaminants but transfer them to the airstream, where they can be destroyed by incineration or oxidation, removed by activated carbon, or released into the atmosphere if relevant emissions criteria are met. 

Other paint stripper ingredients include surface-active agents (surfactants), emulsifiers, thickeners, sealants, and corrosion inhibitors. Thickeners such as methyl cellulose derivatives are used to thicken the stripper so that it can be brushed onto vertical surfaces. Sealants snch as crude or refined paraffin act to retard evaporation of the CH2CI2 so that the stripper remains effective over a long period of time. 

In most similar activities in petroleum refineries, the vapors from stripping "sour water" are processed in a Claus plant. With care in design and operation of the stripper, the vapors typically consist of equal volumes of H2S, NH3 and H2O. Such a mixture can support high-temperature reducing flame in which NH3 is destroyed. 

The cooled process gas that leaves the Syngas Scrubber is fed to the Amine unit. The amine unit consists of an absorption-stripping system plus associated equipment. In this system a circulating amine stream (activated MDEA - or Methyl Diethanolamine) absorbs the C02 in the C02 Absorber. The amine is regenerated in the C02 Stripper with the C02 being recycled to the compressor. 

Surface Area (SA, mf/g). The snrface area is the measure of the catalyst activity (as long as the same catalyst types are compared) and has a strong effect on the performance of an Flnidized Catalytic Cracking Unit (FCCU). High surface area also results in increased adsorption of hydrocarbons, and a higher steam rate in the stripper may be reqnired. The zeolite and matrix surface areas of a catalyst can be analysed separately. Matrix pores provide access of the hydrocarbons to the active zeolite sites and matrix surface area often correlates with the bottoms conversion activity of the catalyst or the Light Cycle Oil (LCO) yield at constant conversion. 

A properly designed deodorizer or stripper vessel, located after the distillation column and operating at high vacuum and with open or sparging steam, will remove close boiling impurities and most odor bodies. Remaining color bodies are removed by adsorption with activated carbon. 

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