the propose of this paper is to introduce a new model for crude oil fouling in preheat trains of crude distillation unit. the experimental results of australian light crude oil with the tube side surface temperatures between 200-260 oc and fluid velocity ranged 0.25 to 0.4m/s were used. the activation energy of chemical reaction depends on the surface temperature has been calculated.  the model...

for energy saving retrofit projects, its economics are usually evaluated in terms of capital investment and payback time. the capital investment is in direct relation to the total heat recovery area of the network and the payback time factor is base on both the area and the energy savings. the debottlenecking is an increased throughput, which can be profitable in economic sense. the combination...

heat and mass transfer, in this paper, is considered in one-row heat exchanger, that fins are hotter than air flow and water is added to fins. related governing equations are derived by analyzing a two-dimension model in a unique cell of a heat exchange. these equations are numerically solved by finite difference method. heat transfer and efficiency under partially wet surface are calculated by...

The calculation of Ground Heat Exchanger (GHE) performance is very important for predicting the performance and estimating the initial cost of geothermal heat pump systems. In North America it is estimated that on average GHE are oversized by about 10% ~ 30%. A vertical Ground Heat Exchanger (VGHE) is most common because of its smaller environmental influence and land field requirement. This pa...

One of the key stages in designing a heat exchanger is optimization process. The enhancement in thermal performance results in a rise in pressure drop and total annual costs. So, finding optimal dimensions of heat exchanger is a key stage in designing process. In this paper, optimization has been done based on entropy generation minimization, where Cuckoo Algorithm aided to reach better results...

This paper describes modeling and on-line optimization of a crude unit heat exchanger network at the Statoil Mongstad re nery. The objective is to minimize the energy input in the gas red heater by optimally distributing the cold crude oil in the heat exchanger network. The steady state mass and energy balance of the 20 heat exchangers in the network yields the process model. This model is tted...

The transport phenomena in scraped heat exchanger crystallizers are critical for the process performance. Fluid flow and turbulence close to the heat exchanger (HE) surface as generated by stirring elements and scraper blades are crucial in this respect as they aim at avoiding an insulating scale layer on the HE surface. For this reason we performed largeeddy simulations of the turbulent flow (...

A vertical geothermal probe consists of two or four polyethylene tubes U-shaped, used for circulating the coolant between the heat pump and the ground. It is installed in a deep borehole and sealed in a special grout, a kind of liquid cement, used to seal the borehole, and avoid the presence of air bags between the probe and the ground. Moreover, the grout provides a heat transfer medium betwee...

Heat exchangers are the most important equipment in refrigeration processes. Design and modeling of heat exchangers operating at low temperatures are different from other regular heat exchangers. This study includes two sections. In the first section, design and modeling considerations needed for evaluating the real thermal behavior of heat exchangers at low temperatures were discussed. The...

The aim of this work is to bring forward a new style heat exchanger about hollow fiber membrane module, and to analyze the performance which can expectantly be applied in the lithium bromide absorption refrigeration system. Polyvinylidene fluoride hollow fiber membrane module was adopted as the new style solution heat exchanger, hot feed solution from the generator flowed into the lumen side of...