CPE 656 by Aiman Salim https://padlet.com/aiman12as/t7am5jindzlikk3b Past Year Question (Question 2) en-us 2022-01-12 02:19:47 UTC 2023-06-03 01:48:58 UTC hello@padlet.com Question 2 (b) 56y7fhtjxu https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987415626 b) Coke is produced when heavy residuum is undergoing coking process. The produced coke is then processed by following a coke drum schedule. By the aid of schematic diagram and coke drum schedule, explain the whole process which occurs in coke drums.

]]> 2022-01-12 03:44:05 UTC https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987415626 Coke Drum 56y7fhtjxu https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987418681 The temperature in the coke drum ranges from 415°C to 450°C (780°F to 840°F) at pressures from 15 to 90 psi. The drum operation cycle is typically 48 hours—a coke drum is usually on-stream for approximately 24 hours before becoming filled with porous coke, and the following procedure is used to remove the coke: 

·               Coke deposit is cooled with water 
·               One of the heads of the coking drum is removed to permit the drilling of a hole through the centre of the deposit 
·               A hydraulic cutting device, which uses multiple high-pressure water jets, is inserted into the hole and the wet coke is removed from the drum 

Coke drums have a substantially shorter useful life than other pressure vessels working in non-cyclic settings due to the high heating and quenching rates of this process. This is because the severe operating temperature cycling stresses the plate and weld with each cycle, and the drum may bulge and finally break in the circumferential weld seams due to their differing strengths. When a result, coke drums are subjected to substantial downtime throughout their useful lives as necessary repairs or partial shell replacements are performed.
]]> 2022-01-12 03:47:03 UTC https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987418681 Low Pressure Coking 56y7fhtjxu https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987423005 Low-pressure coking is a process designed for a once-through, low-pressure operation. The process is similar to delayed coking except that recycling is not usually practiced and the coke chamber operating conditions are 435°C (815°F) with a pressure on the order of 25 psi. Excessive coking is inhibited by the addition of water to the feedstock in order to quench and restrict further reactions of the reactive intermediates. ]]> 2022-01-12 03:50:28 UTC https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987423005 High Temperature Coking 56y7fhtjxu https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987428611 High-temperature coking is a semicontinuous process designed to convert asphaltic residua to gas oil and coke as the primary products. In the process the feedstock is transported to the heater (370°C, 700°F, 30 psi) and finally to the coking unit, where temperatures may be as high as 980°C–1095°C (1800°F–2000°F). Volatile materials are fractionated, and after the cycle is complete, coke is collected for sulphur removal before storage.]]> 2022-01-12 03:54:52 UTC https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987428611 Schematic diagram of coke drum 56y7fhtjxu https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987432948 2022-01-12 03:58:22 UTC https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987432948 Queastion 2 (a) syafiqizuddin97 https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987528224 In catalytic cracking process, conversion is a function of the crackability of the feed. Show 4 typical reactions during this process by the aid of synthesis route. ]]> 2022-01-12 05:26:19 UTC https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987528224 1. Alkane cracking syafiqizuddin97 https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987569191 Zeolites is used as the catalyst in this process. At a temperature of around 500°C and somewhat low pressures, the alkane is brought into contact with the catalyst. The zeolite catalyst has sites that can remove both the hydrogen and the two electrons that bind it to the carbon in an alkane. This results in a positive charge on the carbon atom.]]> 2022-01-12 06:06:24 UTC https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1987569191 Dealkylation of branched aromatics syahir080996 https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1994400938 The dealkylation of methylbenzene, methylbenzene vapour and hydrogen are passed over a catalyst of chromium, platinum or molybdenum oxides, supported on silica or aluminium oxide at 750-870 K at 40-60 atm pressure.]]> 2022-01-16 15:47:22 UTC https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1994400938 catalytic cracking of naphthalene syahir080996 https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1994424499 Hydrogenation of Naphthalene to produce tetralin, the condition of the reaction is in the temperature range of 200–300 °C and pressures of 4–6 MPa with present of platinum-containing catalysts.]]> 2022-01-16 16:08:43 UTC https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1994424499 Methane cracking syahir080996 https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1994453992 methane cracking to produce hydrogen. Methane cracking is not feasible at moderate temperatures. To obtain a reasonable yield, a temperature higher than 1200 C is required with the presence of  Nickel.]]> 2022-01-16 16:32:24 UTC https://padlet.com/aiman12as/t7am5jindzlikk3b/wish/1994453992