Calcium looping process

Figure 17.6 illustrates a gasification process integrated with the calcium looping process. Once the water gas mixture is formed at the exit of the gasifier, calcium oxide fines are injected into the fuel gas stream. As the fuel gas flows past the WGS catalyst, the WGS reaction takes place and forms additional C02. The injected CaO sorbent particles react with C02 and H2S in the gas stream, thereby allowing further catalytic WGS reaction to occur. The reactions involved in the calcium looping scheme are... 

Conceptual flowsheet depicting integration of various units in the calcium looping processes for H2 generation in typical coal-gasifier facility. 

We would also like to stress the importance of additional requirements related to the physical properties such as the mechanical strength of potential CO2 sorbents. The calcium looping process will most likely be operated in a circulating fluidized bed reactor set-up. This requires the development of attrition-resistant materials. However, the mechanical strength or attrition resistance of new developed CO2 sorbents is rarely assessed and, thus, requires more attention if the materials are to be relevant for practical applications. 

Several power plants have been equipped with dual alkali processes. These are throw-away processes with two liquid loops. In one common process, the scrubbing liquid is a clear solution of sodium sulfite. The absorption of sulfur dioxide converts the sodium sulfite to sodium bisulfite. In the regeneration loop, an alkali such as lime slurry is added the sodium sulfite solution is regenerated and a mixture of calcium sulfite and calcium sulfate is precipitated. The slurry is... 

The inverting GH 95 1,2-oc-L-fucosidase (EC 3.2.1.63) from Bifidobacterium bifi-dum in complex (PDB 2EAC) with 1-deoxy-L-fuconojirimycin (20) showed the inhibitor in C4 chair conformation, resembling L-fucose and the entrance to the active site was narrowed by the gate keeper loops.315 A calcium ion associated with the protein was not involved in the catalytic process but was considered to stabilize the enzyme. 

Regulatory processes such as muscle contraction are controlled by temporary conformational changes associated with metal ion co-ordination. Such regulatory processes are frequently associated with metal ions such as Mg2+, Ca2+ and Mn2+ (which possesses a d5 configuration with no crystal field preference for any particular co-ordination geometry). Muscle contraction is controlled by the binding of calcium ions to the protein troponin (Fig. 10-4), with a feed-back loop controlling the release and uptake of calcium ions from an ATP-ase, an enzyme which catalyses the hydrolysis of ATR... 

The typical process for producing a 42% high-fructose syrup is shown in Figure 21.8.32 A starch solution at about 35% solids and a pH of about 6.5 is drawn into a steam jet at 180°F (82°C) in the presence of a calcium-stabilized, thermostable alpha-amylase. The slurry is maintained at this temperature through a series of loops for 3-5 minutes and then cooled to 95°C (200°F) in a secondary reactor, where further alpha-amylase additions occur. A holding time of up to 120 minutes in the secondary reactor produces a solution of approximately 12 DE. The pH is adjusted to about 4.3... 

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