American Journal of Energy Research

A steam condenser is an important component of a power plant, in which the heat of condensation is discharged to the environment. Changes of inlet temperature and mass flow rate of cooling water affect the steam pressure, which has a significant impact on the efficiency and power generated in the low-pressure (LP) part of the steam turbine. On the basis of data obtained from a simulator of the steam condenser and the actual measurement data from a 200-MW power plant, an analysis was performed of how the inlet cooling water temperature, the cooling water mass flow rate, and the steam mass flow rate affect the steam condenser effectiveness, the heat flow, the steam pressure in the condenser, and the efficiency and power of the LP part of the steam turbine. In the case of heat exchangers with a condensation zone, e.g. in a regenerative heat exchanger, the maximum value of the effectiveness ε means obtaining the maximum value of the heated fluid temperature at the outlet. Since the role of the steam condenser (providing the lowest possible vacuum) is slightly different from the role of a classical heat exchanger, increasing the value of ε does not mean better performance of the steam condenser. An even greater disparity exists in the evaluation of the performance of a system comprising the steam condenser and the LP part of the steam turbine. It was therefore suggested to evaluate the performance of the steam condenser and the LP part of the steam turbine using the parameter of efficacy, defined as: δ=(1-ε)=δt_min /ΔT_max. Moreover, for practical purposes, the relation (6) was given for the power of the LP part of the steam turbine as a function of the cooling water mass flow rate and its temperature at the inlet to the steam condenser. Knowing the characteristics of the LP part of the steam turbine and of the steam condenser, one can optimize operating conditions of the system.

American Journal of Energy Research. 2015, 3(1), 13-18. DOI: 10.12691/ajer-3-1-3
Pub. Date: May 19, 2015

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New Method of Solving the Seepage Model for the Multilayer Composite Reservoir with the Double Porosity

by Qiang Wang, Shunchu Li, Mei Luo and Dongdong Gui

Original Research

Aimed at multilayer composite reservoir with the double porosity, meanwhile considering the influence of well bore storage and skin effect, the seepage model for multilayer composite reservoir with the double porosity which the flow was steady from pore to crack was established in different outer boundary (infinite; closed; constant pressure) conditions; the exact solution of reservoir pressure drop and bottom hole pressure drop were obtained by Laplace transform in the Laplace space; the unified expression of solution was obtained by constructing similar kernel functions in different outer boundary conditions, therefore new method which solving this class of reservoir model is put forward, namely similar construction method. This method plays an important guiding role in exploring seepage law of oil and gas reservoir.

American Journal of Energy Research. 2015, 3(1), 8-12. DOI: 10.12691/ajer-3-1-2
Pub. Date: April 21, 2015

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A Novel Integrated Hydrothermal Liquefaction and Solar Catalytic Reforming Method for Enhanced Hydrogen Generation from Biomass

by Anuradha Shende, Richa Tungal, Rajneesh Jaswal and Rajesh Shende

Original Research

Short energy intensive hydrothermal liquefaction (HTL) of biomass in the presence of Ni salt catalyst selectively generates H₂ in the product gas and biocrude mainly containing C₁-C₃ acids (formic, lactic, propionic, acetic), HMF and furfural. The H₂ mass balance indicated that only 3.12 vol% H₂ in biomass (cotton) was released as product gas; 48.7 vol% was captured in the C₁-C₃ acids while the remainder H₂ was trapped in oxygenated compounds and char. Continuing HTL after 120 minutes caused no further increase in gas phase H₂ yields. To enhance the H₂ yields with minimal energy input, solar photocatalytic reforming (PR) of the biocrude with Pt/TiO₂ catalyst was investigated. Photocatalysis of activated carbon (AC) treated biocrude generated an additional H₂, 17.82 wt%. H₂ yields from photoreforming of simulated biocrude acid mixture and actual biocrude were compared. Enhanced H₂ generation was observed with integrated HTL-PR of biomass.

American Journal of Energy Research. 2015, 3(1), 1-7. DOI: 10.12691/ajer-3-1-1
Pub. Date: March 06, 2015

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