Bed batch type

The iron sponge process is very old (introduced in England in the mid-19th century) and very simple. It removes only H S and mercaptans. It is good only for streams containing low H2S concentrations at pressures of 25 to l,200psig. Hydrated iron oxide containing water and of proper pH is supported on wood chips or other material. Water is injected with the gas. 

Regeneration with air can be done with continuous or periodic addition of small amounts of air. Both must be done carefully because of exothermic reaction. Regeneration is never complete, so the beds must be eventually changed out. This must be done carefully because of the pyrophoric (spontaneously combustible) nature of the iron sulfide. The entire bed is wetted first. 

Mol sieve processes can be developed to do almost anything desired remove H2S, sweeten and dehydrate at the same time, remove CO2. remove mercaptans, etc. Regeneration is done by switching beds and sending hot 

There is a Gas Research Institute (GRI) evaluation of a solid-based scavenger (Sulfa Treat ). Full-scale evaluations have been conducted at a production plant in central Texas. The reference is GRI-95/0161. 

GPSA Engineering Data Book, Gas Processors Suppliers Association, Vol. II. 10th Ed. 

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Physical solvent type Fluor solvents (propylene carbonate example), Selexol Physical/chemical type Sulfinol Carbonate type Potassium carbonate Solution batch type Lo-Cat, Chemsweet Bed batch type Iron Sponge, Mol Sieve... 

In order to combine the advantages of a batch type and continuous production, a prototype for a quasi-continuous production line was developed (15-18,33-35). The principle of this quasi-continuous production line is based on a semi-continuous production of mini-batches in a specially designed high-shear mixer/granulator which is connected to a continuous multicell-fiuidized (Glatt Multicell ) bed dryer (Fig. 10). 

In conclusion, the maximum adsorption capacity should be measured in fixed-bed experiments under dynamic conditions, and if models are applicable, diffusion coefficients should be also determined in fixed-bed apparatus. Due to the fact that the equilibrium isotherms require extended data series and thus are time-consuming experiments, the latter are quite difficult to be conducted in fixed-bed reactors and from this point of view, it is more practical to evaluated equilibrium isotherms in batch reactor systems. Then, it is known that when applying fixed-bed models using an equilibrium isotherm obtained in batch-type experiments, the equilibrium discrepancy (if it exists) can be compensated by a different estimate for the solid diffusion coefficient (Inglezakis and Grigoropoulu, 2003 Weber and Wang, 1987). 

H2 conversion was also typically lower than total, ranging from 30 to 70%. A H2 recycle is thus necessary. Staged (sequential) addition of H2 to maintain a more uniform 02 H2 ratio in the reactor and avoid excess 02 has also been shown to improve performances. Batch-type autoclave or continuous fixed bed (trickle-bed) or stirred reactors have been used. Operations were typically under pressure in the 50-100 bar range, again with the exception of the cited CSIR patents. The reaction temperature ranged from 4 to 605 °C. Upon decreasing the temperature, H2 solubility increases, but the catalyst specific activity decreases. The productivity should thus pass through a maximum nevertheless this depends from case to case. Table 8.3 summarizes selected results from recent patents. 

There are many different reactor designs but the two most commonly used are fixed bed and batch slurry phase. For a fixed bed reactor a given volume of solid particulate or monolith supported catalyst is fixed in a heated tube located within a furnace and liquid and/or gaseous reactants flow through the bed. This type of process is commonly used for large continuous-volume production where the reactor is dedicated to making only one product such as a bulk chemical or petroleum product. 

Hardly any batch-type oilseed solvent extractors remain. Three of the more popular types currently manufactured include (1) shallow bed-type extractors, where a 0.5-1.5 m thick layer of collets or flakes is pulled across a linear screen and extracted by drenching with a countercurrent flowing miscella consisting of solvent and solubilized oil (Fig. 34.13) (2) diffusion belt type, where deeper beds of collets or flakes are conveyed on a woven mesh or folding-pan belt while drenched in countercur-... 

Most Raney nickel applications involve the use of fine catalyst particles in a batch type stirred reactor. Raney nickel can, however, be adapted for use in a fixed bed reactor by filling the reactor with the commercially available large granules of the alloy. A 10% solution of sodium hydroxide is passed through the reactor for a sufficient time to remove about 10-12% of the aluminum from the... 

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