Saturday, November 23, 2019

General Checklist List for Pre-start and Starting up the Centrifugal Pumps.

General Checklist the Essential Steps and precautions for Pre-start and Starting up the Centrifugal Pumps.
# What’s the things you Should be attention physically?

# General centrifugal pump start up procedure:-

Before pump start-up you must perform these tasks:-
*01.  Open the suction valve , do priming by venting all the air inside the suction line by opening any vent or even the PG vent till liquid coming out then close , now you confirm no air inside the system to reduce the chances of pump getting cavitation

*02.  Open any re-circulation or cooling lines.

*03.  Fully close or partially open the discharge valve, depending on system conditions.

*04.  Start the driver.

*05.  Slowly open the discharge valve until the pump reaches the desired flow.

*06.  Check the pressure gauge to ensure that the pump quickly reaches the correct discharge pressure.

*07.  If the pump fail to reach the correct pressure, perform these steps:
        a. Stop the driver.
        b. Prime the pump again.
        c. Restart the driver.

*08.  Monitor the pump while it is operating.
       a. Check the pump for bearing temperature, vibration, amp/load and noise.
       b. If the pumps exceed normal levels, then shut down the pump immediately and               correct the problem.

*09. Repeat steps 7 and 6 until the pump runs properly.

Liquefaction Process Technologies for LNG Production

## There’re 4 Liquefaction Process Technologies for LNG Production:-

#01.  C3MR APCI (Air Products) Process.

#02.  Cascade (ConocoPhillips) Process:

* 1- The raw gas is first treated to remove (CO2), (H2S) and other sulfur compounds, (H2O), organometallic mercury compounds, particulates, and other contaminates before it is routed to the liquefaction section of the plant.

*2- The treated gas is then chilled and condensed to approximately -162°C in successively colder heat exchanges, using pure propane (or propylene), ethylene, and methane as refrigerants.

*3- The refrigerant circuits are designed with 2 drivers/compressors for each refrigerant which provides a wide range of turn down capacity and a high degree of availability. For the propane cycle core-in-kettle type exchanges are used. Brazed aluminium plate-fin exchanges (cold boxes) are applied mainly in the ethylene and methane cycles. All the cooling, with exception of the propane chilling, takes place in the 2 cold boxes.

*4- The LNG product is then pumped into storage tanks where it remains until shipment. Boil-off gas and ship return vapors are captured and recycled through the Optimized Cascade process for efficient re‑liquefaction.

#03.  Shell DMR Process.

#04.  Linde Process.

Monday, November 11, 2019

Hydrostatic Test

## Hydrostatic test an Construction Activity in which pressure vessels such as pipelines, Process Piping , gas cylinders, boilers , Fire Extinguishers, Can be tested for strength and leaks. 

# Filling the vessel or pipe system with a liquid, usually water, which may be dyed to aid in visual leak detection. It’s performed to expose defective materials that have missed prior detection, ensure that any remaining defects are insignificant enough to allow operation at design pressures, expose possible leaks and serve as a final validation of the integrity of the constructed system. ASME B31.3 requires this testing to ensure tightness and strength. 

# Buried HP O&G pipelines are tested for strength by pressurising them to at least 125% of their maximum allowable working pressure (MAWP) at any point along their length. 

# It’s a type of pressure test that works by completely filling the component with water, removing the air contained within the unit, and pressurizing the system up to 1.5 times the design pressure limit the of the unit.

# The pressure is then held for a specific amount of time to visually inspect the system for leaks. Visual inspection can be enhanced by applying either tracer or fluorescent dyes to the liquid to determine where cracks and leaks are present.

Sunday, November 10, 2019

Deaeration Process

Boiler Feed Water Treatment Deaeration Process:

## The process through which the dissolved gases are removed from water is called "Deaeration". The equipment, which is used in this method, is called "Deaerator".

Why do we use deaerators?...
The Deaerator (DA) tank uses steam to preheat boiler feedwater to a temp. at which dissolved O2 & CO2 will become separated from the feedwater before it is pumped to the boiler. The purpose is to protect the boiler and steam/condensate piping from corrosion that would be present when the water evaporates into steam.additional benefit is that the amount of chemicals used to treat the boiler water can be reduced. 
# Dissolved CO2 combines with water to form carbonic acid that causes further corrosion. 

# Working Principle of Deaerators :-
1️⃣ by Henry’s Law- Accordind to William Henry state that gas solubility in a solution decreases as the gas partial pressure above the solution decreases. In simple we can say that The solubility of any gas dissolved in a liquid is directly proportional to the partial pressure of the gas. Solubility of gases decrease with increase in solution temperature and or decrease in pressure.
2️⃣ The second principle state that deaeration is the relationship between gas solubility and temperature. Easily explained, gas solubility in a solution decreases as the temp.of the solution rises and approaches saturation temperature.​​ 

# Main Types of Deaerators:-
1️⃣ Tray type Deaerator 
2️⃣ Spray type Deaerator 

3️⃣ Pressurized type Deaerator

Saturday, 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 = H1 = H2 =…. If the characteristics of the pumps differ too much, this relationship may not be applicable.

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 turbine blades and reduce horsepower output. When these deposits break off, the turbine rotor is unbalanced. The resulting vibration will cause the shutdown of the turbine. 
*️For Steam Superheat Furnace Tubes salts in entrained moisture from a boiler will deposit inside the superheat coils. Localized overheating and tube rupture will result.

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 startup️ 

# 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 flow due to malfunctioning of the upstream side check valve. 

# There are some centrifugal pumps, called axial or propeller pumps, for which the delivery valve has to be kept open at a min. % as determined by the pump characteristics so, the reason for keeping the delivery valve in the minimum open condition is to minimize the starting torque imposed on the motor.

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
πŸ—œ 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
πŸ”‹Tangential flow is the term applied when the steam enters through a nozzle placed approximately tangent to the periphery and directed into semicircular buckets milled obliquely into the edge of the wheel.

4️⃣ Mixed Flow
🚏Mixed flow is applied to the flow when it enters in the radial direction and leaves in the axial direction. These types of radial inflow turbines have been widely used with gasses and, in some cases, with steam.



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 motive fluid nozzle is very high. High-velocity motive fluid entrails and mixes with the suction fluid. The resulting mixture is still supersonic. As the mixture passes through the convergent throat and divergent sections of the diffuser, high velocity is converted back to pressure. 

Glycol Dehydration Basic Process

The process of removing water from a substance is called dehydration. Gas can be dehydrated by cooling and separating the condensed liquids, by using specially designed low-temperature separation process, by using solid desiccants, or by using a liquid desiccant. Cooling the gas and removing the free water with a separator is the simplest method of dehydration. However, this method is limited by the hydrate formation temperature unless some other hydrate preventive method has been taken. Although there are several methods for removing water from gas, the most commonly used dehydration method utilizes a liquid desiccant known as glycol An Article on Gas Dehydration Process: (Gas Conditioning and Processing) Covering

■Water in Natural Gas

■Glycol Dehydration Basic Process

■Process flow and Components
▪︎Inlet Separator
▪︎Contactor Column
▪︎Heat Exchanger
▪︎Flash Vessel
▪︎Surge Tank

Tank blanketing

Tank blanketing

# Tank blanketing also referred to as tank padding, is the process of applying a gas to the empty space in a storage tanks

# Tank blanketing is typically involved using a buffer gas to protect products inside the storage container.

#Benefits of Storage Tanks, blanketing System includes:-
1-      Longer life for the product in the Tank
2-      Reduced hazards like a fire hazard
3-      Longer equipment life cycles.

# Blanketing systems usually operate at a slightly higher than atmospheric pressure (a few inches of the water column above atmospheric), Higher pressures than this are generally not used, as they often yield only marginal increases in results while wasting large amounts of expensive blanketing gas.

# The most common gas used in blanketing is nitrogen for its inert properties, availability and relatively low cost.

# Tank blanketing is used for a variety of products as refinery products, these applications also cover a wide variety of storage containers.

# When considering the use of tank blanketing for combustible products, the greatest benefit is process safety. Since fuels require oxygen to combust, reduced oxygen content in the vapor space lowers the risk of unwanted combustion.

# Tank blanketing is also used to keep contaminants out of storage space.

About Storage Tanks

✅ Storage tanks containing organic liquids, nonorganic liquids, vapors and can be found in many industries. Most storage tanks are designed and built to the API-650 specification.

✅ 8 Types of Storage Tanks:-1️⃣ Fixed-Roof tanks
                                                   2️⃣ External floating roof tanks
                                                  3️⃣ Internal floating roof tanks
                                                  4️⃣ Domed external floating roof tanks
                                                  5️⃣ Horizontal tanks
                                                  6️⃣ Pressure Tanks ( Spherical)
                                                  7️⃣ Variable vapor space tanks
                                                  8️⃣ LNG tanks

✅ These tanks are almost exclusively above ground. Horizontal tanks can be used above and below ground. Pressure tanks often are horizontally oriented and spherically shaped to maintain structural integrity at high pressures. They are located above the ground. Variable vapor space tanks can be cylindrical or spherical in shape.
✅ “ Secondary Containment “ of a product should be built around the tanks are made of brick or concrete and the lining should be impervious to liquid stored to prevent spills that can cause fire, property damage or contaminate the environment. ✅ The containment must be at least = the tank capacity +10% to contain the volume of the tank (in case of spillage or fire)+ the water and foam which will be used to put off the fire.

What Is Gas Hydrate. How To Create It On Pipeline And How To Prevent It?

Gas hydrate.
Gas hydrate.
✅ Simply hydrate is a compound, typically a crystalline one, in which water molecules are chemically bound to another compound or element.

✅ When gas molecules are trapped in a lattice of water molecules at temperatures above 0°C and pressures above one atmosphere, they can form a sta­ble solid. These solids are gas hydrates. Most gas hydrates are formed from methane (CH4). Methane is the simplest hydrocarbon and is the primary component of NG that we burn for energy.

✅ Hydrate formations in pipelines are dangerous and costly it leads to:-
1️⃣ slow down the flow of oil and gas through a pipeline.
2️⃣ block pipelines altogether. That means a production slow down
3️⃣ cause pressure build-ups that can end in fire and explosions.

NPSHr “ Net Positive Suction Head

️ NPSHr “ Net Positive Suction Head Required “ at the first stage impeller to ensure successful Pump operations.

πŸ“Œ NPSHr is determined by the manufacturer with hydraulic testing. It is not determined by the system design – that would be NPSHa, or the net positive suction head available. NPSHa must always be > NPSHr to avoid the cavitation phenomena.

️ Min. Submergence is the amount of liquid required above the pump’s suction pipe to prevent a vortex from being created which can cause air entrapment and pre-rotation. The min. submergence is determined by the factory using a formula that is based upon the geometry and flow characteristics of the pump.

️ If the system characteristics do not meet the submergence or NPSH requirements of the pump, cavitation can occur in either case. If a vortex forms because the liquid level is too low, air can enter the pump and cause damage to the pressure changes. If there is not enough suction head available, the fluid pressure will fall below its vapor pressure inside the pump, leading to bubble formation & collapse(Cavitation).

️ To satisfy the Min. Submergence requirement, just add more liquid! In order to avoid NPSHr issues, you can add liquid, add pressure to the suction source, or reduce frictional losses in the suction system.

Methanol – CH3OH

Methanol – CH3OH – is four parts hydrogen, one part oxygen and one part carbon.

On an industrial scale, methanol is predominantly produced from natural gas by reforming the gas with steam and then converting and distilling the resulting synthesized gas mixture to create pure methanol. The result is a clear, liquid, organic chemical that is water soluble and readily biodegradable.

Methanol can be produced from natural gas, coal and renewable sources such as municipal waste, biomass and recycled carbon dioxide.

Friday, November 8, 2019

How does a liquid ring vacuum pump work.

How does a liquid ring vacuum pump work
What’s the Main Pump Components and its Principle of Operations
 A  liquid ring pump is a rotating positive-displacement pump, They are typically used as a vacuum pump, but can also be used as a gas compressor.

 The liquid-ring pump compresses gas by rotating a vaned impeller located eccentrically within a cylindrical casing.

 Liquid (usually water) is fed into the pump and, by centrifugal acceleration, forms a moving cylindrical ring against the inside of the casing.

 This liquid ring creates a series of seals in the space between the impeller vanes, which form compression chambers.

 The eccentricity between the impeller's axis of rotation and the casing geometric axis results in a cyclic variation of the volume enclosed by the vanes and the ring.

 Gas, often the air is drawn into the pump through an inlet port at the end of the casing.

 The gas is trapped in the compression chambers formed by the impeller vanes and the liquid ring. The reduction in volume caused by the impeller rotation compresses the gas, which reports to the discharge port at the end of the casing.

 the liquid ring performs 2 other important functions:-
1️⃣ It absorbs the heat generated by compression, friction, and condensation of the incoming vapor.
2️⃣ It absorbs and washes out any process contaminants entrained in the gas.

 A continuous supply of service liquid is necessary to limit the temperature rise in the pump caused by the heat of compression, friction, and condensation. Any excessive rise in temperature will have a detrimental effect on performance, reducing the capacity and degree of vacuum attainable.

Difference between LNG, LPG and NGL

✅ LNG — Liquefied Natural Gas, is gas that has been Liquified at very low temp. and is transported as a liquid. It’s Primarily methane ,NG is a mixture of HC which, when liquefied, form a clear colorless,odorless liquid; it’s usually transported and stored at a temp. very close to its boiling point at atmospheric pressure (~ -160), The actual composition of LNG will vary depending on its source and on the liquefaction process, but in all cases the major is methane with small percentages of the heavier HC such as ethane, propane, butane and pentane ,N2 may be present. 

✅ LPG — Liquefied Petroleum Gas gas that is liquid near room temperature and at some extent of pressure. This product has very little methane and butane and is primarily propane (C3),LPG is more dense (has a higher specific gravity) than natural gas ,Their common characteristic is that they can be compressed into liquid at relatively low pressures ,The two most common LPG constitutes are Propane and Butane.

 ✅ NGLs — Natural Gas Liquids,are heavier gaseous hydrocarbons that are included in the raw natural gas stream from the wellhead , Raw natural gas also contains impurities including water vapor,(H2S), CO2, helium, N2, and other compounds that must be removed.