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Showing posts from November 9, 2019

Pumps Operating in Series and Parallel:

Centrifugal pumps are joined in series or in parallel to meet certain operational requirements. They are joined in series  (Fig. 10.18a)  when the delivery head requirements are high as in case of pumping in high rise buildings or operating sprinkler systems etc. Two or more pumps may be joined in such a way that the delivery of one becomes the inflow into the other. Pumps are joined in parallel (Fig. 10.18b) when they have a common source and pumping head is the same. In situations like pumping from rivers or a pond or dewatering of foundations, pumps could be joined in parallel. The pumps will now operate against the same head H = H 1  = H 2  =…. If the characteristics of the pumps differ too much, this relationship may not be applicable. PLEASE READ MORE..... Industrial Catalyst And Classification. Electrical Hazards And Precautions. Renewable, Sustainable, Clean, or Green Energy. What Is Renewable Energy Or Renewable Resources, Or Clean Energy? Standar...

Steam Quality....

 #Poor quality steam refers to high moisture content, Steam is best when superheated.  From the perspective of Process Design Engineering, we assume that even saturated steam is dry.  *In reality, steam in most process plant piping systems is wet. Often steam is wet because of ambient heat loss.  *Dry steam is actually invisible. Steam venting from a line only looks white because the steam is wet.  *Wet steam is generated from boilers because of entrainment of BFW into the evolved steam. *Entrained boiler feed water contains salts. The TDS of the entrained water is the same as the boiler blowdown  *Salt content of the blowdown water is 10-20 times > the salt content of the boiler feedwater. That’s why moisture in steam due to entrainment is more serious than moisture in steam due to condensation. Condensed moisture is free of salts.  ️*For Steam Turbines Moisture in the supply steam contains salts. The salts slowly accumulate on the ...

Why we need to close the(discharge) isolation valve of a centrifugal pump during start up.

Why we need to close the(discharge) isolation valve of a centrifugal pump during startup ⁉ ️  # Answer(1)  ✳ ️ It is general practice to close the delivery valve of the centrifugal pump during start-up and it is highly recommended for the critical services where the liquid is at boiling/bubble point (Ex. Reflux pump of distillation column). The procedure is to close the valve and start the pump. After this open discharge valve slowly till 100% this stabilizes the complete system. If this procedure is not followed and the valve is kept 100% open and the pump is started, NPSHa for this will be minimum because of losses due to acceleration during startup. This will result in cavitation of the pump.  # ️ Answer(2)  1️⃣ To minimize the starting torque on the motor.  2️⃣ To load the delivery pipe network gradually if it is the only pump that feeds the network.  3️⃣ If it is a parallel-connected pump, this method will insure against any reverse ...

Steam Turbine

Steam turbine consists of 4 basic parts:-  1️⃣ Rotor, which carries the blades or buckets  2️⃣ Stator, consisting of cylinder and casing, which are often combined and within which the rotor turns 3️⃣ Nozzles or flow passages for the steam, which are generally fixed to the inside of the cylinder 4️⃣ Frame or base for supporting the stator and rotor There’re 4 Directions of the Steam inside ST:- 1️⃣ Axial Flow 🗜 It signifies steam flow substantially parallel to the axis of rotation, among blades that are set radially. This is the only arrangement used in medium and large turbines and is most commonly used also in small turbines. 2️⃣ Radial Flow ⌛ ️It’s obtained when the steam enters at or near the shaft and flows substantially radially outward among blades, which are placed parallel to the axis of rotation. 3️⃣ Tangential (Helical) Flow 🔋Tangential flow is the term applied when the steam enters through a nozzle placed approximately tangent to the ...

STEAM EJECTOR WORKING PRINCIPLE

‼️STEAM EJECTOR WORKING PRINCIPLE‼️  An Ejector is a device used to suck the gas or vapor  from the desired vessel or system. An ejector is similar to an of vacuum pump or compressor. The ejector is a static piece of equipment with no moving parts consist of 4 components:-  1️⃣ The Motive Nozzle  2️⃣ Motive Chest  3️⃣ Suction chamber  4️⃣ Diffuser  How it Works 1️⃣ The ejector converts pressure energy of motive steam or other working fluid into velocity.  2️⃣ Thermodynamic-ally , high velocity is achieved through adiabatic expansion of motive fluid through a convergent-divergent nozzle. 3️⃣ This expansion of the motive fluid from the motive pressure to the suction fluid operating pressure results in supersonic velocity at the nozzle exit. The motive fluid expands to a pressure equal to the suction fluid pressure, This creates a driving force to bring suction fluid into an ejector. 4️⃣ the velocity exiting a motiv...