H2S Production

Triple Iron Agar works in a similar manner but contains three sugars, low concentrations of glucose, high concentrations of lactose and sucrose, Phenol Red and ferrous sulfate. 

Both of the above media should only have their caps screwed on loosely after inoculation to allow the ingress of air, thus enabling the alkaline reaction to be produced. In both cases it is necessary to confirm the biochemical results in single sugar media. 

---

The potential surfaces of the ground and excited states in the vicinity of the conical intersection were calculated point by point, along the trajectory leading from the antiaromatic transition state to the benzene and H2 products. In this calculation, the HH distance was varied, and all other coordinates were optimized to obtain the minimum energy of the system in the excited electronic state ( Ai). The energy of the ground state was calculated at the geometry optimized for the excited state. In the calculation of the conical intersection... 

A more efficient route is based on use of 2iac vapor. Ziac vapor is absorbed ia molten lead to form a 20—30% solutioa, which is coatacted with steam at 300—500°C and 10—20 MPa (100—200 atm). The H2 product is withdrawn, and the ZnO removed from the lead is reduced and recycled (180). 

In the FCC, HjS is formed principally by the catalytic decomposition of non-thiophenic (non-ring) sulfur compounds. Table 2-3 shows the effects of feedstock sulfur compounds on H2S production. 

Self-Test 18.8A Write the condensed structural formula of the product of the addition of hydrogen to 2-butene CH3CH=CHCH3 + H2 — product. 

Fig. 6. Performance of control system with set point change in H2 production rate by 10% at 15 sec...

Figure 1 also shows an Induction period during which the rate of H2 production accelerates. Although this effect Is more pronounced for the hexagonal CdS sample. It Is present In both. Further results, summarized In Fig. 2, emphasize this Induction period. The curves labelled (1) and (2) Involved repeated use of the same film. Between runs (1) and (2) the film was washed In boiling water. 

Similar results have recently been reported by Aspnes and Heller. They proposed an autocatalytic model for photoactive systems involving metal/compound semiconductor interfaces. To explain induction times in CdS systems (.9), they suggest that hydrogen incorporated in the solid lowers the barrier to charge transfer across the interface and thereby accelerates H2 production rates. 

This result was interpreted by the formation of a Schottky barrier at the CdS/ Ru02-interface as already discussed in the previous section. The H2-production at CdS/Ru02-suspensions could be considerably increased by addition of sulfite because the latter rved as a sink for sulfur produced via reaction (40)... 

Two basic concepts for microbial H2S production were tested with field data ... 

H2S production in the mixing zone between formation water and injection water (mixing zone model)... 

H2S production caused by the growth of sulfate-reducing bacteria in a biofilm in the reservoir rock close to the injection well (biofilm model)... 

Field data obtained from three oil producing wells on the Gullfaks field correlated with H2S production profiles obtained using the hiofilm model but could not be explained by the mixing zone model. 

Formation of insoluble sulphides from H2S production by sulphate reducing bacteria can bring about blackening of products (Figure 11) and some bacteria such as Serratia and Flavobacteria species and yeasts, including Rhodotorula can give pink or yellow discolorations. Other bacteria such as the Pseudomonads can produce fluorescent pigments. 

Table II. H2S Production and Activity of Lemons Treated with Sulfur35 and Sulfur35 Acids and Incubated at 44° C.

CO2 in Figure 225(c) induces also non-equilibrium state and enhances CO2 production, then H2 productivity and purity are also enhanced. These separation processes would realize not only high-yield of H2, but also decrease of temperature of the endothermic reforming. It means that the separation process is important methodology for energy media transformation and chemical energy conversion. 

---