Gas scrubbing and cooling

Excessive 02-in-gas levels, on the other hand, give S03 in the product gas. This S03 is inadvertently absorbed during gas scrubbing and cooling - which ... 

Gas Scrubbing and Cooling. If the gas contains fluorine, two scrubbing towers in series may be required to remove the fluorine completely. This step is necessary primarily to protect the catalyst in the contact section of the acid plant. Excess scrubbing liquor from the second scrubber is transferred to the first scrubber, and the weak acid purge from the system is taken from the first scrubber. 

Contaminated feedstock is heated in an indirectly fired rotary dryer. The vapors are then transported to a gas treatment system via an inert gas such as nitrogen where they are scrubbed and cooled to condense the organics. The carrier gas is reheated and recycled to the dryer. The recovered organics can be reclaimed, used on-site or off-site as fuel, or incinerated. The technology is available in laboratory-, pilot-, and full-scale systems. 

The needs of gas coking-plants differ from the needs of gas generators. The poorest quality coke is utilized in gas generators and in the manufacture of water-gas. The gas given off from the ovens is a heavy yellowish gas, with a temperature of 1800°F. Before it can be used it has to be scrubbed and cooled. The gases are sent through a series of condensers... 

Following scrubbing and cooling, suspended droplets of scrubbing solution or mist are removed in wet electrostatic precipitators. The cleaned gas may stiU contain unacceptable levels of mercury vapour, which must be removed before transfer of gas to the acid conversion plant. There are a nnmber of mercnry removal techniques but the most commonly used is the Boliden-Norzink mercury removal process, which uses mercuric chloride solution to scrub the gas and absorb mercury according to Eqnation 4.7 (Dyvik, 1985) ... 

Recycling should be practiced for dust control and gas scrubbing, as well as for cooling water, condensates, rainwater, and excess process water used for washing. 

The gas, along with entrained ash and char particles, which are subjected to further gasification in the large space above the fluid bed, exit the gasifier at 954—1010°C. The hot gas is passed through a waste-heat boiler to recover the sensible heat, and then through a dry cyclone. Solid particles are removed in both units. The gas is further cooled and cleaned by wet scrubbing, and if required, an electrostatic precipitator is included in the gas-treatment stream. 

For diffusing gases of similar molecular weight, the properties that control heat transfer follow the same rules as those that control mass transfer. As a result, the NH3 scrubbing and gas cooling processes achieve similar approaches to equilibrium. 

The Sauter mean diameter has been found to be the most useful of the above definitions for characterizing the spray produced by a nozzle. It is a good indicator of a spray s performance in complex interactions with a droplet s surface and volume. Applications include spray drying, evaporative cooling, dry scrubbing, gas quenching, and gas absorption (Stavis, 1991). 

Sodium amide (2.79 mol) and 110 ml light mineral oil were heated to 45 °C whereupon hexamethyldisilazane (0.03 mol) was added. Over 50 minutes, 3-chloro-2-methylpropene (2.23 mol) was slowly added and the evolving gas scrubbed with water then condensed in a dry ice cooled trap. The total product weight consisted of 39.5 g of which 39.3 g comprised 1-methyl-cyclopropene. 

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