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  1. where are the questions?
  2. Sorry marketing not allowed..
  3. great initiative... Do start blog on this site as well
  4. What are the most important and recognised certificates related to Environmental Protection or Environmental Management for a Chemical Engineer? Asked by Daniele Pugliesi on
  5. Dear Chemical Engineering professionals, Please accept New year wishes. Lets come together and wish every one by replying to this post. Happy new Year Hope the new year brighten up your Chemical Engineering profession. Freshers get the desired job Researchers get success in their projects All of us can get an opportunity to work in desired role and in desired company For those who are looking to start up as an entrepreneur can get the first move on Entrepreneurs who have recently started can take their work to new level Please do share - how will you like to take off in your Chemical engineering profession- What are your new year resolutions?
  6. From the album Process Flow Diagrams

    Introduction • Ethylene oxide is produced by the oxidation of ethylene using air. • Ethanolamines are produced using the series reaction scheme of ethylene oxide with ammonia. • Ethanolamines are significantly used as absorbents to remove CO2 and H2S from process gas streams. Reactions • C2 H4 + 0.5 O2→ CH2 O.CH2O • Ethylene to air ratio: 3 – 10 % • Side reaction products: CO2 , H2O • Catalyst: Silver oxide on alumina • Operating temperature and pressure: 250 – 300°C and 120 – 300 psi • Supressing agent for side reactions: Ethylene dichloride • Reaction is exothermic • Air and ethylene are separate compressed and along with recycle stream are sent to the shell and tube reactor. • The reactor is fed on the shell side with Dowtherm fluid that serves to maintain the reaction temperature. A dowtherm fluid is a heat transfer fluid , which is a mixture of two very stable compounds, biphenyl and diphenyl oxide. The fluid is dyed clear to light yellow to aid in leak detection. • The hot dowtherm fluid from the reactor is sent to a waste heat recovery boiler to generate steam. • The vapour stream is cooled using a integrated heat exchanger using the unreacted vapour stream generated from an absorber. • The vapour stream is then sent to the heat integrated exchanger and is then sent back to the reactor and a fraction of that is purged to eliminate the accumulation of inerts such as Nitrogen and Argon. • The product vapors are compressed and sent to a water absorber which absorbs ethylene oxide from the feed vapors. Eventually, the ethylene oxide rich water stream is sent to a stripper which desorbs the ethylene oxide + water as vapour and generates the regenerated water as bottom product. The regenerated water reaches the absorber through a heat integrated exchanger. • The ethylene oxide + water vapour mixture is compressed (to about 4 - 5 atms) and then sent to a stripper to generate light ends + H2O as a top product and the bottom product is then sent to another fractionators to produce ethylene oxide as top product. The heavy ends are obtained as bottom product.
  7. From the album Process Flow Diagrams

    Introduction • Vinyl chloride is produced in a two step process from ethylene. • Ethylene first reacts with Chlorine to produce Ethylene dichloride. • The purified Ethylene dichloride undergoes selective cracking to form vinyl chloride. • We first present the process technology associated to Ethylene Chloride . Reactions • C2H4 + Cl2 → C2H4Cl2 • Undesired products: Propylene dichloride and Polychloroethanes. • Reaction occurs in a liquid phase reactor with ethylene dichloride serving as the liquid medium and reactants reacting the liquid phase. • Catalyst is FeCl3 or Ethylene dibromide. Process Technology • C2H4 and Cl2 are mixed and sent to the liquid phase reactor. • Here, the feed mixture bubbles through the ethylene dichloride product medium. • Reactor operating conditions are 50°C and 1.5 – 2 atms. • The reaction is exothermic. Therefore, energy is removed using either cooling jacket or external heat exchanger. • To facilitate better conversion, circulating reactor designs are used. • FeCl3 traces are also added to serve as catalyst. • The vapour products are cooled to produce two products namely a vapour product and a liquid product. The liquid product is partially recycled back to the reactor to maintain the liquid medium concentration. • The vapour product is sent to a refrigeration unit for further cooling which will further extract ethylene dichloride to liquid phase and makes the vapour phase bereft of the product. • The liquid product is crude ethylene dichloride with traces of HCl. Therefore, acid wash is carried out first with dilute NaOH to obtain crude ethylene dichloride. A settling tank is allowed to separate the spent NaOH solution and crude C2H4Cl2 (as well liquid). • The crude ethylene dichloride eventually enters a distillation column that separates the ethylene dichloride from the other heavy end products. • The vapour phase stream is sent to a dilute NaOH solution to remove HCl and produce the spent NaOH solution. The off gases consist of H2, CH4, C2H4 and C2H6.
  8. From the album Process Flow Diagrams

    Kvic model (Floating Drum Model) It consists of a deep well shaped underground digester connected by inlet and outlet pipes . a mild steel gas storage drum, inverted over the slurry goes up and down around a guide pipe corresponding to the accumulation and withdrawal of gas. Benefits: ○Capacity to maintain steady pressure of biogas by the movement of gas holder ○Inbuilt provision for scum breaking ○Volume of gas is known just by observing the position of the drum
  9. From the album Process Flow Diagrams

    Fixed Dome The main feature of this design is that the digester and gas holder are the part of composite unit made of brick masonry. It has a cylindrical digester with dome shaped roof and large inlet and outlet tank. Advantages: ○The plant is cheaper than the floating drum plants by 20-30%
  10. Which is your favorite chemical engineering subject / specialization & why ?
  11. Version


    What is Chemical Engineering & difference from chemical process
  12. Version 2


    Separation Trains Azeotropes
  13. From the album Chemical Engineering Images

    Gas containing a mist of droplets enters the unit via a tangential inlet. First coarse droplets, larger than 10 mm, are separated in the pre-separator section. The pre-separator acts as a cyclone and collects the droplets in the stationary pre-separator collection volute. This liquid leaves via the tangentially connected pre-separator liquid outlet. The gas stream, containing the remaining mist of mainly micron- sized droplets, enters the rotating element. In the design point the rotating element can be driven by the impulse of the rotating flow. An external drive and freewheel can be added for rotating speed, and thus separation, control. While traveling in the axial direction through the rotating channels, the droplets are driven to the channel walls by centrifugal force and coagulate into a thin film. The rotating element thus acts as a droplet coalescer. For optimal film behavior and minimal pressure drop the flow direction through the element is downward out of the channels. Due to gravitational and shear forces, the film is forced
  14. From the album Chemical Engineering Images

    This kind of phase diagram is a “hybrid” ofthe diagram with complete solid and liquid solution and the eutectic diagram (the metals are completely soluble in liquid state and entirely insoluble in solid state). Consider solidification of an alloy with concentration C. When the alloy temperature is higher than TL, single liquid phase exists (point M on the diagram). When the temperature reaches the value TL (point M1 on the liquidus curve) solidification starts. According to solidus curve the first solid crystals (primary crystals) of the α-phase have composition C1. Further cooling of the alloy causes changing of the liquid phase composition according to the liquidus curve and when the alloy temperature reaches a certain intermediate value T (position MT ), liquid phase of composition Cy and solid α-phase of composition Cx are in equilibrium. At the temperature equal to TE (eutectic temperature) formation of the primary crystals stops and the remainding liquid phase , having composition CE (eutectic composition), transforms to a finely devided mixture of small solid crystals of α-phase and β-phase (eutectic phase transformation). At this temperature all α-phase crystals have composition Cα and all crystals of β-phase have composition Cβ. Relative amounts of the α-phase primary crystals and the eutectic mixture may be calculated by the “lever rule” : WP / WE = M2E / M2N or WP / WE = (CE-C) / (C- Cα) Where: WP – weight of the α-phase primary crystals; WE – weight of the eutectic mixture; Just below the eutectic temperature TE the alloy consists of two solid phase: α-phase and β-phase, relative amounts of whichis determined by the “lever rule” : Wα / Wβ = M2F / M2N or Wα / Wβ = (Cβ-C) / (C- Cα) Where: Wα – weight of the α-phase; Wβ – weight of theβ-phase; During further cooling solid solution phases (α-phase and β-phase) change their compositions according to the solvus curves NN3 and FF3 . Solvus curve determins formation of solid solution phase from another solid solution phase – similar to liquidus curve. At the temperature T3 α-phase crystals have composition Cα and all crystals of β-phase have composition Cβ. Hypo-eutectic alloys If an alloy composition C is lower, than eutectic composition CE , solidification of the alloy starts from formation of the primary crystals of α-phase according to the left branch of the liquidus curve. These alloys are called hypo-eutectic. Hyper-eutectic alloys If an alloy composition C is higher, than eutectic composition CE , solidification of the alloy starts from formation of the primary crystals of β-phase according to the right branch of the liquidus curve. These alloys are called hyper-eutectic. Eutectoid phase transformation is analogous to the eutectic transformation, however it occurs with a solid solution phase, breaking up into a mixture of two finely divided phases of different compositions.
  15. From the album Chemical Engineering Images

    Valves can be classified by: ** The operative of the valve closure member ** The kind of closure member movement defines both the geometry and operative of the valve. - Multi-turn valve (linear motion valves): The closure member has a linear displacement generally by turning its threaded stem several times. This operation is slow, but it gives accuracy and stability to position the closure member, which is necessary in some control valves. Types of valves: Gate valve, Globe valve, Fixed cone valve, Needle valve and Pinch valve. ------------ - Quarter-turn valve (rotary valve): The closure member as well its shaft turn 0º-90º; from the fully-open position to the fully-closed position. They are quick opening/closure valves. Types of valves: Ball valve, Butterfly valve, Plug valve, Spherical valve. ------------------------------------------------------------- ** The functionality of the valve ** • Control: pressure / flow rate regulation. • Closure at over-speed flow. (i.e. immediate closure if downstream pipeline is broken by accident). • Overpressure protection. • Back flow prevention (check valve). • On/Off service. ------------------------------------------------------------ The nature and physical conditions of the flow • Low/High temperatures. • Low/High pressures. • Cavitation risk. • Corrosive or erosive properties of the flow. • Viscosity: Gas, liquid, solid. • Hygiene requirements (for the food or pharmacy industry...). • Explosion and risk of inflammability (chemical, petrochemical industry). ---------------------------------------------------------------- ** Other forms of valve classification ** • Admissible leakage level. • Connection to the pipe. • An unique direction of the flow or bidirectional flow. • Number of ports: most of the valves have two port, named inlet and outlet port. But for same applications there are multi-port configured valves. They can be three-way and four-way valves. • Angle between the inlet and outlet port of the valve.