Scrubbing operation

These reactions are used industrially for scrubbing operations and for selective removal of H2S from natural gas containing CO2. 

Make a list of all the costs associated with running a wet scrubbing operation to remove particulates and SO,. What cost factors could be eliminated or reduced if a pollution prevention technology or practice that used about the same energy and manpower requirements was applied. 

Mixing Valve This type of mixing device is normally a manually operated globe valve operated at 20 to 350 kPa pressure drop. Common use of this device in refinery operations is for water and crude oil mixing before a desalter and in caustic scrubbing operations. 

Sulfur dioxide emissions from power plants can be reduced by spraying a water solution of calcium hydroxide directly into the smokestack. This "scrubbing" operation brings about the reaction... 

Steel Coke-oven gas scrubbing operation Ammonia, sulfides, cyanides, phenols... 

After extraction, the loaded solvent contains 6 g T1 zirconium as zirconium oxide with 0.2% hafnium oxide. The raffinate is left with 0.2 to 0.3 g l l of the oxides of zirconium and hafnium of this, 70-90% is hafnium oxide. This raffinate can act as a feed solution for the recovery of pure hafnium oxide. The loaded extractant, on the other hand, is subjected to a scrubbing operation with pure zirconium sulfate solution to eliminate any co-extracted hafnium. This scrubbing operation is essentially a displacement reaction ... 

Removing water from the operation completely if it is extraneous (e.g. replace the scrubbing operation used to separate an organic contaminant from a vapor stream by condensation, or replacing an extraction process using water by cooling crystallization). 

Increasing the number of stages in absorption and scrubbing operations that use water to reduce the water consumption for the same separation. 

A variation of the nonregenerable absorption is the spray dry process. Lime slurry is sprayed through an atomizing nozzle into a tower where it countercurrently contacts the flue gas. The sulfur dioxide is absorbed and water in the slurry evaporated as calcium sulfite—sulfate collects as a powder at the bottom of the tower. The process requires less capital investment, but is less efficient than regular scrubbing operations. 

Most of today s distillate HDS processes consist of fixed-bed, down-flow reactors configured in a manner similar to that shown in Fig. 8 (7). It should be noted that hydrogen is used in excess and is recirculated after scrubbing out the H2S byproduct. Care must be used in the scrubbing operation as it is necessary to maintain a low but optimum level of H2S in the recycle stream to maintain catalyst stability and activity. The consequence of this H2S requirement when hydrotreating PASCs to extinction is discussed in more detail in later sections, but at this point it should be mentioned that H2S is a strong inhibitor of HDS for PASCs. 

Hollow rubber parts may have a small opening such as in hot water bottles or in many chemical and medical industry applications, or may be completely closed as in play balls, or with round metallic cores encompassed within balls which are used in scrubbing operations in some separation processes in the chemical industry. After... 

The purpose of such scrubbing operations may be any of the following gas purification (eg, removal of air pollutants from exhaust gases or contaminants from gases that will be further processed), product recovery, or production of solutions of gases for various purposes. Several examples of applied absorption processes are shown in Table 1. 

At the start of an operation, water or ammonium sulfite solution can be used as the scrubbing liquid. If water is used, primary ammonia and steam must be injected to the gas and the scrubbing operation must continue for several hours prior to regeneration of any ammonia. This builds up a salt solution. If a sulfite solution is used (3.0% ), ammonia regeneration can begin immediately. 

If all SOo is not converted to a solid salt, part or all of the remainder is absorbed during the scrubbing operation. The degree to which this action occurs appears to be directly proportional to the pH of the scrubbing solution and the rate at which scrubber solution is recycled to the distribution plate. 

After the scrubbing operation, the solution of salts is exposed to sodium hydroxide solution chemical reaction releases ammonia and steam for recycle. 

During the scrubbing operation some of the sulfites are oxidized to sulfates the oxidation products appear to be continuously removed from the scrubbing liquor by similar reactions in the regenerator. 

The Electrochemical Membrane Separator (EMS) technology being developed is compared to a wet removal process with subsequent Claus Plant processing to elemental sulfur and SCOT Tail Gas treatment of flue gases. This wet process utilities aqueous Methyldiethanolamine (MDEA) as an absorbent in a scrubbing operation to bring the HjS level from 1.7% to 4 ppm. The flow rate to these processes is 50MM SCFD and the process pressure is 715 psi. The... 

The reaction gas is cooled to ambient temperature in a water spray column, and the quench water that condenses is fed back in a closed cycle to the electric arc reactor. The gas is then compressed and subjected to a sequence of scrubbing operations with selective solvents [i.e., methanol, octane, and A/ -methyl-2-pyrrolidone (NMP) in that order]. The solvents are regenerated by low-pressure stripping with gas fractions from the production process. This removes mainly the polyunsaturated hydrocarbons. 

Pollution control has been a major objective in the last 15 years. As a result of innovation and development, process improvements have refined scrubbing operations of MAP/DAP/NPK fertilizer plants so that effluents have decreased vastly 11,2]. This has been achieved by improvements in equipment but primarily by careful management of the scrubbing fluids to the extent that scrubbing has almost become a process by itself. 

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