Natural Gas Pricing Mechanism Reform and its Impacts on Future Energy Options in China
Natural gas is the cleanest fossil fuel. In recent years, its demand in China has been increasing at a rapid pace, but its pricing mechanism is still based on the planned economy system and is not keeping up pace with that of its consumption. Therefore, reforming the existing pricing system is of great significance. This paper first reviews the evolution of the pricing mechanism of natural gas in China, and then examines with model predictions the feasibility of a nationwide implementation of the reform programs currently carried out in Guangdong and Guangxi and its possible impacts. The results show that the reform can: (a) benefit Chinese natural gas producers and importers by increasing their profits, (b) increase the production of natural gas and accelerate the development of the industry, (c) reduce the use of natural gas in the chemical industry and optimize the energy consumption structure in China, (d) change the current energy portfolio in China and achieve the goal of sustainable development, and (e) help Chinese companies enhance their ability of adapting to high prices and promote their international competitiveness.
Sensitivity analysis of technical and economic parameters for natural gas management in enhanced oil recovery projects
Since oil reservoirs have different properties, each reservoir performs differently during enhanced oil recovery (EOR) processes. In some cases, water injection is the most effective method, while in others, gas injection or other methods will result in better performance. Most reservoir simulations assume that the amount of injection fluid is sufficient. However, in practice, the amount of available gas is enough to supply only a limited number of reservoirs. This study presents a comprehensive model which examines oil reservoirs in concert based on mathematical programming, and considers the competition between them. This model entails sensitive analysis of gas injection projects in order to determine effective factors (technical and economic parameters) on decision-making relating to gas injection projects. Results show that technical and economic parameters such as oil price, gas quality and gas price variation have a marked effect on economic results and may lead to favorable economic conditions. Variations were made in the model regarding changes in interest rate, number of wells and injection pressure, but these variations did not lead to unfavorable economic conditions; in other words, changes in these factors had no significant effect on stability.
Wall-to-bed heat transfer in circulating fluidized beds
Heat Transfer from the wall of a circulating fluidized bed to the fast bed suspension has been investigated for several materials. The range of investigation includes dense and dilute phase fast fluidization and pneumatic transport. The overall heat transfer coefficient was found to be a function mainly of cross-sectional average suspension density. Effects of superficial velocity and solids mass flux were obscured by their interrelationship to the suspension density. Two models from the literature are evaluated using present and published data.