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About krishnaswamy

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  1. A thin electrical heater is wrapped around the outer surface of a long cylindrical tube whose inner surface is maintained at a temperature of 5˚C. The tube wall has inner and outer radii of 25 and 75 mm, respectively, and a thermal conductivity of 10 W/m.K. The thermal contact resistance between the heater and the outer surface of the tube (per unit length of the tube) is 0.01 m.K/W. The outer surface of the heater is exposed to a fluid with T∞= 10˚C and a convection coefficient of h = 100 W/m2.K. The heater power per unit length of tube (W/m) required to maintain the heater at To = 25˚C is:
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    PRETREATMENT OF CRUDE OILS Crude oil comes from the ground, which contains variety of substances like gases, water, dirt (minerals) etc. Pretreatment of the crude oil is important if the crude oil is to be transported effectively and to be processed without causing fouling and corrosion in the subsequent operation starting from distillation, catalytic reforming and secondary conversion processes. IMPURITIES Impurities in the crude oil are either oleophobic or oleophilic. OLEOPHOBIC IMPURITIES: Oleophobic impurities include salt, mainly chloride & impurities of Na, K, Ca& Mg, sediments such as salt, sand, mud, iron oxide, iron sulphide etc. and waterpresent as soluble emulsified and /or finely dispersed water. OLEOPHILIC IMPURITIES: Oleophilic impurities are soluble and are sulphur compounds, organometallic compounds, Ni, V, Fe and As etc, naphthenic acids and nitrogen compounds. Pretreatment of the crude oil removes the oleophobic impurities. PRETREATMENT TAKES PLACE IN TWO WAYS:  Field separation  Crude desalting lecture3.pdf