Abstract Against the background due to the energy crisis in the late 1970’s, the pinch analysis has emerged as a powerful tool for the integrated design of process heat networks which include heat exchangers, distillation columns, furnaces, etc..The key strategy of this methodology is to set energy targets prior to design based on basic thermodynamic principles.The subject of this thesis in to apply this analysis to one of the Libyan Refineries, namely Ras Lanuf Refinery, to assess energy utilization of such big energy – consuming plants and to explore the potential of energy as well as capital costs savings based on the finding of applying this analysis. Based on actual operating data collected from the plant and application of the procedure of the pinch analysis to this real case study where a minimum temperature difference approach in the Ras Lanuf refinery heat exchangers design of 10 (ΔT min =10 ) the following results were obtained. Actual rate of energy consumption of the base case design of the refinery is 9MW which is provided by burning fuel oil in the furnace, while the minimum target predicted by the pinch analysis should be 8MW. This amounts to just over 11% energy savings which equivalent to $462,000 per year reduction in the operating cost of the refinery
هويدة الهادي الحبيشي (2011)

Abstract Deposition of undesirable materials on water wall side of boiler tube that are operated under forced circulation boiling conditions can cause serious trouble in steam boilers. The present study is concerned with the scaling characteristics of water in the boilers. The effects of heat flux and water velocity were evaluated for water having a total hardness and calcium hardness in the range (TH= 380 to 390 ppm asCaCO3 ) and(CaH= 250 to 298 ppm asCaCO3) respectively. The heat flux ranged from (1.05 x 105) to and water velocity in a vertical annular test section range from 0.51 to 0.75 m/sec (1.67 to 2.5 ft/sec) . The test section consisted of an annular duct 0.050 m (2.0-in) O.D. and 0.033 m (1.33-in ) I.D. A 0.30 m (12-in) section of the concentric core of the annulus was electrically heated. Hot water at 97.0 (370.1) was circulated through the annulus where boiling occurred on the heated section. The temperature range at the Surface of heated section in the annulus was from (105 - 118 ). The results of five tests are reported in this study. The fouling resistance vr. time curves reached an asymptotic value and the average of fouling resistance for Runs (1-5) had been plotted. Chemical analysis of scale deposits indcated that Calcium carbonate and Silica were the man Constituents. At constant surface temperature an increase in velocity from 0.51 to 0.75 m/sec (1.67 -2.5 ft/sec), caused about a 20 percent reduction in the asymptotic fouling resistance.
عادل محمد شنقير (2008)

Abstract Recently more than 150 million tonnes of plastics were produced in the world. On the one hand, the consumption and production of polymers are increasing, on the other hand as landfill and incineration become more expensive and less accepted .The increasing amount of polymer wastes from them generates further mainly environmental problems. The recycling of plastic wastes is gaining increasing importance. Pyrolysis is one promising method for the treatment of mixed and contaminated plastic wastes. In this way the plastic wastes are converted into fuels or other valuable feedstock for the petrochemical industry. In present work catalytic cracking of waste plastics blend with HGO [Libyan gas oil supplied by the Zawia Oil Refinery Company boils in the range of 275-375Cº] was investigated using H-ZSM5and H-BETA. Reaction systems that were studied included high density polyethylene HDPE and polypropylene blend with HGO, reactions were carried out in one litre micro autoclave reactor under different conditions of weight, temperature and type of catalyst, The optimum conditions were 2.5% catalyst by weight of total feed stock, one hour, atmospheric presser and three temperatures selected 400Cº, 425Cº and 450Cº. The product distribution for the system [plastics and HGO] provided some good results high yield of liquid [gasoline] up to 210Cº, gases and small amount of heavy oils. Some analysis was used to qualify and quantify the product. The results from GC.MS analysis showed that the yield of gasoline (c5-c12) over H-ZSM5 higher than H-BETA. In case of 5%PP, 15%HDPE and 80%HGO over H-ZSM5 at 450Cº, 96% total conversion achieved. The result from TGA in the same case is 15% by weight. Also the theoretical calculations to quantify the produced gases after burring of waste plastic in rotary kiln reactor have been evaluated. it is found that the suitable ratio of CO:H2 to produce methanol is 7:1
بسمة محمود التونسي (2010)