JOURNAL OF CONVERSION OF ENERGY
Year:2010 | Volume:1 | Issue:1|Papers Count:7

The aim of this work is to perform a retrofit study of a methanol plant in Fan-Avaran Petrochemical Complex as a case study using pinch analysis with the purpose of improving energy efficiency and decreasing exergy loss. The main source of the exergy loss in the process is the synthesis reactor outlet steam with a high temperature and pressure. However, instead of a proper use of its exegy content, its temperature and pressure are currently reduced in a valve and a water cooler, respectively. In this project, the integration of a turbo-expander with the synthesis reactor was proposed to exergy loss recovery electricity-power or shaft-work generation. However, the process heat exchanger network should be targeted and modified for shaft-work recovery using pinch analysis with pressure drop consideration. The results showed that by applying pinch analysis and integrating a turbo expander into the sample methanol plant about 80 MW electricity power can be generated and the project payback time will be less than 28 months.

In this paper, the possibility of power producing in a sequence of distillation columns in a chemical process is inspected. The aim is to find the best sequence with its feasible power production as a means of achieving a minimum TAC (Total Annual Cost). First, all sequences have been simulated with commercial software and then, feasible power production in each sequence is examined. After finding the best values for parameters of each sequence, all sequences are compared and finally the optimum state for the process is found. Results show the high optimization of TAC by power generation in the indirect sequence (1X2&2X3).

This article aims to apply the Genetic Algorithm (GA) technique to estimate natural gas demand in Iran in terms of the socio-economic indicators. GA demand estimation models are developed in two forms (exponential and linear) and applied to estimate the natural gas demand values based on population, gross domestic product (GDP), import and export data. Two different scenarios are designed for future forecasting of each input variable (Regression Methods and Artificial Neural Networks). Natural gas consumption in Iran from 1981 to 2005 is considered as the case for the present study. The available data are partly used for finding the optimal, or near optimal, values of the weighting parameters (1981-1999) and partly for testing the models (2000–2005).Validations of the models show that GA models are in high agreement with the observed data (i.e. MAPE errors for GAlinear and GAexponential were 4.13% and 3.89%, respectively). Natural gas demand in Iran is forecasted up to year 2030.

Open expanding tank (OET) includes a wide range of application in central heating and air conditioning systems. Lack of proper engineering design causes faulty structure to lose a plenty of heat.Therefore, in this experimental research, the structure of OET is being reviewed and all parts of which have been reformed or modified ultimately to reduce heat and energetic losses. In the first step, the made Samples in the market are considered, and disadvantages, problems and extension potentials are marked too. Then the selected scenarios modeled and compared using fluent software and scientific contributed computing, thereafter the final scenario has been set. Then a pilot laboratory for the sample model setup has been made. Energy audit procedure and monitoring operations have been taking place for complementary approach. For checking audit errors and omitting targets, the results statistics are being reviewed again. On the last step, the selected setup model, has been reevaluated by economical analysis. Final model that has been introduced with the name (Optimized twin container OET) is able to decrease heat losses between 85 to 95 percent compared to the common types available in the market. The results account for an economical investment by the private sector.

This paper aims to survey a certain type of the slider-crank mechanisms and to compare its performance with the conventional kind for a four-stroke SI engine. This comparison includes the modeling of thermodynamic processes, vibration and internal forces. Moreover, this study explore the advantages and disadvantages of those mechanisms. The parameters used in the study are friction of piston skirt, type of lubrication, the number of rings, amount and duration of the fuel burning, spark advance, mass of the parts, crank angular velocity, thermodynamic properties of inlet air and temperature of the cylinder body.

The gas turbine performance desirability depends entirely on its load level. In this paper, the performance of a 264MW V94.3A-Siemens gas turbine in the 2000MW Rodshur power plant was analyzed thermodynamically at 60% and 100% load levels and the undesirable effects on its performance due to using it at 60% load level were studied. By applying energetic and exergetic analyses and providing practical examples as well as a software based analysis, we tried to present the concept and application of those analyses to investigate the thermodynamic behavior of the power generator unit, while reducing its load level. Finally, this study compared the output of both energetic and exergetic analyses and investigated the negative impacts of the unit load level reduction on its thermodynamic behavior and the increase of cycle losses.