Ring process

HyPr-RING Process, Direct Production of Hydrogen from Coal.114... 

HyPr-RING method was proposed in 1998 in 2000, a project started in Japan to develop this method to a commercial process. Figure 3.14 shows the concept of FlyPr-RING process. Two chemical loops are included in this process. The first chemical loop is the water cycle. 

Concept of HyPr-RING process. (Adapted from Shiying, L., Michiaki, H., Yoshizo, S., and Hiroyuki, H.,... 

The feasibility of performing the water-carbon oxidation-reduction reaction in combination with the C02 absorption by CaO in a single reactor has been confirmed in experiments.1112 The underlying concept of the HyPr-RING process involves two reactors a main... 

A high partial pressure of steam is used to hydrate the CaO so that the exothermic reactions of carbonation supply a sufficient amount of energy for the endothermic gasification reaction. The calcium-based sorbent used in the HyPr-Ring process is either CaO or CaO/Ca(OH)2. 

It is estimated that a H2 production efficiency of 77% can be achieved using the HyPr-Ring process, while producing a sequestration-ready, pure C02 stream (Lin et al., 2005). The distribution of carbon or coal between the two reactors is determined by the amount of heat required in the second reactor for the calcination. 

Kinetic parameters of metabolism of fluorinated analogues of propanolol by cytochrome enzyme (recombinant CYP1A2) have been determined. They clearly indicate that the A-dealkylation process was 10-fold lower for the N—CH2CF3 compound with respect to propanolol itself. Hydroxylation of the naphthalene ring process is not observed in the case of propanolol but it becomes the major process with the fluoro analogue (Figure 3.13)." The same decreased metabohsm trend has also been observed with lower pKa values for CYP2D6 cytochrome enzyme." ... 

The metal redox precedes the ring process for MoO(Cor) (Scheme 82).248... 

In some cases, degradation products may be produced as a result of attack on both the aromatic ring and aliphatic components of the compound. This is the case for diuron where hydroxylated photoproducts 1 and 2 (Scheme 4) are produced by reaction of HO with the aromatic ring (Process A) to form an adduct similar to that described above with subsequent loss of a chlorine atom [15]. The more important degradation pathway in this instance is via hydroxyl radical attack on the methyl of the dimethylurea group (Process B). 

The metal redox intervenes the ring process in some transition metal phthalocyanines. Fe and Co change their oxidation state from M to M, and Mn and Cr from M" to M" between the first ring redox steps, while OTi, OV, Ni", Cu and Zn are unaffected. 

The ratio of partial pressure, Pco2Ph2/Ph2oPco/ is decreased by the CO2 absorption. Thus, the equilibrium of the WGS reaction can be operated at a higher temperature with simultaneous CO2 removal. The overall reaction of the HyPr-RING process can be written as ... 

The Los Alamos National Laboratory proposed a Zero Emission Coal Alliance (ZECA) process [27] for hydrogen production from coal, in which coal is first gasified via a methanation process without combustion. Like the HyPr-RING process, CaO is also introduced as a CO2 sorbent. The ZECA method can be expressed as the following steps [27] ... 

Figure 5.6. Ring process for diffusion offoreign atoms...

Remark.- The same exchange was proposed by a more complex process called ring process, utilizing four close atoms (Figure 5.6). 

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