Chemical recuperation

Similar schemes are being considered for transport of energy from concentrated solar energy plants [44] [155]. It is possible to achieve solar fluxes at 1000 kWW at 1000 C, which is far above the fluxes in conventional tubular reformers of 100 kW/m (refer to Sections 1.2.2 and 3.2.2). One solution has been to separate the reforming reaction from the solar receiver by having a separate loop of a heat transfer media (as helium for the nuclear reactor). This was studied at first in a sodium heat pipe reformer [363]. However, reactors for direct absorption of the solar 

The exhaust gas from an SOFC fuel cell provides a hydrogen containing clean fuel gas mixture for the combustion chamber of the gas 

As a thermochemical cycle chemical recuperation is a heat engine converting high-temperature heat into chemical energy. Like a steam cycle resulting in mechanical energy the efficiency depends on the operating temperature and the irreversibilities of the individual process steps [156], 

Tops0e mono tube reformer pilot plant Houston 

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However in practice, for the same states 1-5 the steam raised S will be less hence there is no advantage in operating a STIG plant in this variation of the basic CBTX recuperative gas turbine plant. Nonetheless, this form of analysis as developed by Lloyd will prove to be useful in the discussion of the chemical recuperation plant in Chapter 8. 

Lloyd. A. (1991), Thermodynamics of chemically recuperated gas turbines. CEE.S Report 256, Centre For Energy and Environmental. Studies, University Archives, Department of Rare Books and Special Collections, Princeton University Library. 

These cycles involve modification of the combustion process, and employ thermo-chemical recuperation (TCR) to produce a fuel of higher hydrogen content. Three simple CRGTs are ... 

Thermo-chemical recuperation using steam (steam-TCR)... 

The basic idea of using TCR in a gas turbine is usually to extract more heat from the turbine exhaust gases rather than to reduce substantially the irreversibility of combustion through chemical recuperation of the fuel. One method of TCR involves an overall reaction between the fuel, say methane (CH4), and water vapour, usually produced in a heat recovery steam generator. The heat absorbed in the total process effectively increases... 

Cycles B with modification of the fuel in combustion through thermo-chemical recuperation [TCRj... 

We consider next the cycles B of Table 8.IB and the associated Figs. 8.9-8.12 these cycles involve modification of the fuel used in the combustion process by TCR. There are two basic types of chemically recuperated gas turbine (CRGT) cycle ... 

Fig. 8.9. Cycle Bl. Chemically recuperated cycle with steam reforming.

Fig. 8.9 shows a chemically recuperated cycle [Bl] of the first type, i.e. chemical recuperation with steam reforming (steam/TCR). 

Fig. 8.14. Cycle B3. Chemically recuperated plant with fllue-gas reforming (after Newby ct al. 6 ).

Chemical Recuperation of Waste Heat by Utilizing Organic Chemical Hydrides... 

The onboard hydrogen supplied from organic chemical hydrides will be utilized well in the ICE vehicles. Even for stationary use of hydrogen, distribution of organic chemical hydrides will play an important role at stations or sites, where waste heat at modest temperatures is dissipated in vain without chemical recuperation. 

Saito, Y., S. Hodoshima, A. Shono, and K. Otake, Chemical recuperation of low-quality heats with use of dehydrogenation catalysts for organic hydrides. Proceedings of 9th Asian Hydrogen Energy Conference, Tokyo, 2007. 

It is the aim of this paper to present a comparison of thermal and chemical recuperation options 1n a thermodynamic framework. The paper will begin by identifying the major irreversibilities in a simple gas-turbine cycle with liquid methanol fuel continue with a comparison of thermodynamic losses and overall efficiencies among various options utilizing thermal and/or... 

It is not the purpose of this paper to evaluate the suitability of methanol as a fuel for gas turbines. Consequently, no attention will be given to such factors as the cost of methanol fuel, safety considerations of exchanging heat between hot exhaust gases and fuel, and the dynamics of the complex cycle with recuperative chemical reactions. The purpose of this paper is to outline the thermodynamic Implications of chemical recuperation using methanol fuel as an example. 

In order to clarify these ideas, we need to compare the irreversible entropy productions (or the exergy destruction) in cycles that utilize regenerative heating of compressed air, thermal recuperation in the form of evaporation and superheating of the methanol fuel, and chemical recuperation through either reforming or cracking reaction with methanol. The next section presents such a comparison in a simplified form to illustrate the utility of thermodynamic analyses. 

In addition to the simple cycle without any form of recuperation (Base Case) that was analyzed in the previous section, we will consider five separate cases with thermal and/or chemical recuperation. In the interest of maintaining uniformity, we will assume a constant temperature of 800F as the exit temperature of any stream undergoing such recuperation. A description of the five cases is as follows ... 

The total amount of regenerated heat for each of the cases is broken down into three separate thermal energy flows the amount needed to preheat the compressed air (Q ), the amount absorbed by the fuel during thermal or chemical recuperation (Q ), and the... 

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