Regenerator column

The HF concentration of the acid catalyst is maintained ia the range of 85—95% by regeneration within the unit s fractionation faciUties. A separate acid regeneration column (not shown ia Figure 2) is also iacluded to provide a means to remove excess acid-soluble oils and water. The regeneration of acid ia the unit accounts for the low consumption of fresh acid by the HF process. 

The fixed cost( ) of a moving-bed adsorption or regeneration column is given by 30,0O0V , where V is the volume of the column (m ) based on a 15-minute residence... 

Regenerate column with NaOH store column/media in 20% ethanol or 0.05% sodium azide... 

Fig.2 shows the experimental results of Co(NH3)6 reduction, which is done in a stirred reactor at 80 °C and pH 4.1. It can be seen that activated carbon can promote the [Co(NH3)6] reduction significantly. The [Co(NH3)6] " conversion reaches 81.2% with6.7g/l activated carbon in the aqueous solution while only 8.18% of [Co(NH3)6] is reduced when there is no activated carbon added. Thus, a regeneration column packed with the activated carbon should be equipped with the absorber. 

Alkylation generates relatively low volumes of wastewater, primarily from water washing of the liquid reactor products. Wastewater is also generated from steam strippers, depropanizers, and debutanizers, and can be contaminated with oil and other impurities. Liquid process waters (hydrocarbons and acid) originate from minor undesirable side reactions and from feed contaminants, and usually exit as a bottoms stream from the acid regeneration column. The bottoms stream is an acid-water mixture that is sent to the neutralizing drum. The acid in this liquid eventually ends up as insoluble calcium fluoride. 

Figure 6.7-4. Extraction column with reflux and separation of extract in regeneration column...

The example CO2 capture process, shown in Figure 8 as an Aspen Plus EO model representation, is part of an ammonia plant. Designed to scrub CO2 from ammonia synthesis gas, it includes an absorber and two solution regeneration columns, one stripping the rich, C02 laden solution leaving the absorber to semilean concentration of absorbed CO2, and the other cleaning the solution even further to lean solution... 

To improve the LoHeat process, a fifth stage of solution flashing was added along with mechanical vapor recompression (MVR) to boost the fifth-stage flashed steam back to the pressure of the regenerator column. The combination of ejectors plus MVR for multi-stage heat recovery is referred to as the Benfield Hybrid LoHeat Process. If this improvement is combined with ACT-1 activator the energy consumption can be reduced to 600 kcal/Nm3 of C02 removed. 

The extraction plant was designed for 160 bar maximum pressure and an upper temperature limit of 180°C. All parts which have to withstand pressure are made of 1.4571 stainless steel. The main extraction column comprises 5 segments with 1,5 meters length each. The packed height of the first regeneration column is 3 meters, the second regeneration column contains 1,5 m packing. The inner diameter of all columns is 67 mm. 

To investigate the effectivity of the installed wire mesh packing in the first regeneration column, the loaded gas can be fed at the bottom section or in the middle of the column. The partially regenerated gas leaves through the top of the column and is again expanded (RV4) and heated (WT2) to reach a complete regeneration. 

The bottom vessels of all described columns are intentionally of small volume to minimize the column hold-up. This is particularly of advantage when extract reflux is withdrawn from the first regeneration column to the head of the main extraction column, because the time for reaching stationary operation conditions is shortened. The bottom products of all columns are removed continuously through pneumatic controlled valves, which get their signal from capacitive level indicators. 

As products are removed from the extraction and regeneration columns, gas losses are unavoidable. To maintain constant pressure within the extraction system a refill mechanism is installed, which takes the state of gas into account. 

The regenerated extraction gas leaves the second regeneration column at its head and is cooled down in (WT3) to a temperature of approximately 20°C. Depending on the type of extraction solvent the buffer vessel (KP) contains liquid phase in equilibrium state with gas or merely gas of high density. In the last case a pressure controlled pneumatic pump feeds fresh solvent into the circular process. If a gas/liquid equilibrium is achieved in the buffer vessel the gas pressure remains constant until a minimal amount of liquid remains there. For this purpose two optical sensors are introduced into the buffer vessel registrating the minimum and maximum extraction liquid level If the level falls below minimum, fresh liquid extraction solvent is refilled. 

The pressure control system is directly connected to the gas refill system. Pressure is measured by pressure gauges at the top of each column. It is kept constant by the subsequently installed pneumatic regulated expansion valves. If the pressure of the second regeneration column becomes too low the gas refill system is activated (see chapter 2.1.4). 

CO is extracted by countercurrent absorption in a column operating at about 2.10 Pa absolute, with a feedstock inlet temperature of about 40 C and effluent exit around 65 C. This is accompanied by the physical dissolution of small amounts of other constituents, including hydrogen, which are salted out by cooling and expansion of the extract at 0.5, 10 Pa absolute Thecomple.x obtained is then preheated to 100 to 105 C and sent to a regeneration column. In this column, operating at 0.15.10 Pa absolute, CO is liberated... 

The extract is then flashed to liberate, the dissolved olefins and. after recompression, to return them to the extractive distillation step. The liquid fraction rich in butadiene and acetylenic compounds is preheated and sent to a regeneration column with 20 trays operating at about 0.2.10 Pa, at 90°C at the top and 150°C at the bottom. The solvent drawn off is recycled, possibly after purification if required. The distillate is partly condensed. The liquid fraction sei es as a reflux, and that in the gas phase is recompressed and partly returned to the absorption step. The crude butadiene remaining is rid of methyiacetylene and heavier compounds in two simple distillation columns, with about 40 and 110 trays respectively, in the presence of r-butylpyrocatechol. 

Gases containing carbon dioxide enter the bottom of an absorption tower and ascend against the flow of a descending solvent which preferentially absorbs carbon dioxide. The cracked gases, devoid of carbon dioxide, exit the top of the column. The carbon dioxide rich solvent exits the bottom of the tower and is passed to a regenerating column where typically the solvent is boiled to expel the carbon dioxide and regenerate the solvent which is passed back to the absorption tower. 

Figure 24 A scheme for KNO3 production (sulfonate cation exchanger KU-2 X 8 3.0-4.0 mol/dm solutions) (1) column for KNO3 synthesis (2) resin regeneration column (3,4) systems for electrolyte displacement (5-8) tanks.

Figure 26 A scheme for automation unit (1) countercurrent columns (2) regeneration column (3) screws (4) feed pumps (5) pumps for moving resin (6,7) top and bottom resin tanks (8) solution feeders (9) electric motors (10) valves-collectors (11) platinum contacts (12) screw tanks (13) jets (14) resin valves (15) solution distributions (16) a delivery cap (17) tanks for regenerated resin (18) bypass pipe (19) solution tanks.

Figure 28 The Pennutit contactor (1) sorption column (2) regeneration column (3) tank for regenerated resin (4) tank for exhausted resin (5-7) valves (8-17) taps.

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