Scrubbing column

A typical emergency scrubber system consists of a scrubbing column (often filled with packing), recirculating liquid pumps, solvent cooler, and in some cases (where the entering effluent gas/vapor is at a low pressure) exhaust blowers (see Fig. 23-57). Redundant equipment and instrumentation is usually provided to ensure reliable scrubber operation at all times. 

In effect catalyst is regenerated through a scrubbing column to separate A1 Cl3 and Sb Cl3 from a hydrocarbon sludge which is discarded. 

Dissolver. The irradiated Pu/Al targets are dissolved in nitric acid in a dissolver placed in station 1 of the Petrus cell. This dissolver includes a reactor, bubble trap, condenser and soda scrubbing column for uncondensable gases. The reactor, built of Uranus 55 stainless steel, has an effective capacity of about 50 L. 

Nitric Oxide. Since photolysis of NO2 did not proceed measurably before irradiation, as indicated by zero ozone readings for systems containing NO2 in zero air, the NO readings obtained before irradiation for these systems and for the system of Figure 1 are artifacts of the analytical method. The positive error is probably attributable to the scrubbing column used to remove NO2 before the NO oxidation step. Either less... 

Numerous freezeout collections were made and analyzed. The air was drawn through a semicarbazide column and a caustic scrubbing column. The stream was then split one half passed through an irradiated flask and then into a series of traps, and the other half passed through a dark flask on its way to the traps. By examining... 

Hanfoid [D3]. Nitrite concentration in feed to the HA column of a standard Purex plant was adjusted to route most of the neptunium in inadiated natural uranium into the extract from the HS scrubbing column. Sufficient ferrous sulfamate was used in the partitioning column to reduce neptunium to Np(IV), which followed uranium. This neptunium was separated from uranium by fractional extraction with TBP in the second uranium cycle. The dilute neptunium product was recycled to HA column feed, to build up its concentration. Periodically, irradiated uranium feed was replaced by unirradiated uranium, which flushed plutonium and fission products from the system. The impure neptunium remaining was concentrated and purified by solvent extraction and ion exchange. 

The off-gas system ensures that the bulk of active material escaping from the furnace is trapped in a coimtercurrent water-scrubbing column and recirculated directly to the calciner. Further off-gas treatment includes a condenser, an absorption colunm, and a washit colunm. The low-activity liquid from this section of the plant is recycled to the adjoining reprocessing plant. 

This type of unit features the main steps encountered in partial condensation. The available gas mixture, previously dried on molecular sieves, is cooled to around — 120 C by heat exchange in a series of piaicexchangers operating in countercurrent flow on the cold purified products, and is then introduced at the bottom of a tray column with a downflow of liquid methane. The operation takes place at a pressure of abont 1.6.10 Pa absolute. It yields hydrogen with a purity better than 98.5 per cent volume, and which contains less than 10 ppm of CO. After expansion and partial vaporization, the extract feeds a distillation colnmn operating at 0.2. 10 Pa absolute, which separates the carbon monoxide at the top with a yield of at least 80 per cent at a purity over 99 per cent volume, and liquid methane at the bottom. This methane provides reflux to the scrubbing column and partly to the feed cooling uuiL... 

The EO is steam stripped (8) from the scrubbing solution and recovered as a concentrated water solution (9) that is suitable as feed to a glycol plant (11) or to an EO purification system (10). The stripped water is cooled and returned to the scrubbing column. 

Furan resins cost approximately 30-50% more than polyester resins and do not have as good of an impact resistance as the polyesters. They find application as piping, tanks, and special equipment such as scrubbing columns. Refer to Reference [2] for more information regarding furan piping systems. 

The scrubbing column should be operated at as low a temperature as possible. This is because values... 

It must not foam in the scrubbing column and must wet the packing well. 

In vapor treatment the tendency is toward well-designed scrubbing columns, either packed columns for the recovery of ammonium nitrate and ammonia, or low pressure-drop trays for the recovery of ammonium nitrate and nitric acid 132,33,34,35]. For process condensate treatment, the ion-exchange process 136] is also considered to be an effective and economical method. 

Scrubbing column process conditions are nonuniform (in time and in space), promoting corrosion and the development of hot spots. 

In any solids-processing operation, dust control is an important consideration. Where the solid product is conveyed from the apparatus, as with an air mill, highly efficient particle collection is necessary. Combinations of cyclones and bag collectors are often used in this application. Even when recovery is uneconomic, bag collectors may be used to prevent the nuisance of dust release. Other apparatus that does not recover the solids in an immediately useful form may also be used. This category includes wet scrubbers (e.g., venturis and various scrubbing columns) and electrostatic precipitators. 

The Texaco process with the quench mode is shown in Figure 6.2.28 (Appl, 1999). The quench is followed by two-step soot-scrubbing, a venture-scrubber and a countercurrently operated packed scrubbing column. The soot is extracted from the water with naphtha, and the soot-naphtha suspension is... 

Plate fin heat exchanger (3) Scrubbing column (4) Hydrogen stripper (5) CO/CH4-separation column (6) Compressor (7) Expansion turbine. 

A wash unit consists of a scrubbing column in which the raw COj is fed in countercurrent to a cooled water/wash solution circulation. The liquid enriched with impurities is drawn from the sump of the column and partly replaced by fresh water/solution at the top of the column. Water scrubbing is only applied when the raw CO2 is not already the CO2 fraction of a gas scrubbing. It is sometimes installed upstream of the compressor to be used as a direct gas cooler. 

The selectivity and conversion adopted in the Base Case were within the upper range of data reported by Hunter et al. (1985). Conditions of the three Sensitivity Cases were chosen to show effects of process variations. Note that Case DPOM-4 was the same as the Base Case except for using an adiabatic reactor and no CO2 removal. It was found that, since CO2 has a high molar heat capacity, no CO2 removal in the recycle loop resulted in a lowering of the recycle ratio for the same adiabatic AT. A water scrubbing column, however, was added after the separator to minimize the amount of CH3OH being recycled back to the DPOM reactor. 

Exhaust Gas Treatment The gas effluent must be treated to comply with environmental regulations. The exhaust gas from the reactor contains traces of organic matter and unreacted SO3 and SO2 gases. The first two impurities are removed by the electrostatic precipitator. The remaining SO2 gas is removed by the reaction with caustic soda solution flowing countercurrently inside the scrubbing column. The concentration of the residual SO2 in the exhaust gas vented into atmosphere is kept at 5 ppm maximum, well below the allowable standards. 

---