@usmanrasheed
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Oxy-fuel combustion is the process of burning fuel using pure oxygen instead of air. Since the nitrogen component of air is not heated, fuel consumption is reduced, and higher flame temperatures are possible. Historically, the primary use of oxy-fuel combustion has been in welding and cutting of metals.
Advantages:
1. The mass and volume of the flue gas are reduced by approximately 75%.
2. Less heat is lost in the flue gas.
3. The size of the flue gas treatment equipment can be reduced by 75%.
4. The flue gas is primarily CO2, suitable for sequestration.
5. The concentration of pollutants in the flue gas is higher, making separation easier.
6. Most of the flue gases are condensable; this makes compression separation possible.
Low NOX production.
Challenges:
High installation and operating costs. Not mature technology. Lots of work on lab scale and small power plants but on large scale still needs work.
For general information please visit.
Linde Engineering shows several references
The simple Oxy-fuel combustion process by Linde can be seen on the link. -
RON is a research Octane number, it is measured in a standard engine in Laboratory, at 600 RPM at a lower temperature.
MON is Motor octane number, which is measured at higher intake temperatures (preheated fuel) and higher engine speed (900 RPM). Its purpose is to measure the octane number near the actual condition at the high speed of the car engine. -
Standard and Vanadium-alloyed, chromium, and molybdenum 2,25Cr–1Mo steel grades (EN 10028-2 12CrMo9-10/ASTM A387 gr. 22 and 13CrMoV9-10/ASTM A542 tp. D) is commonly used for the fabrication of heavy pressure vessels for applications in petroleum refining plants.
These reactors are made of heavy plates, forged shells, forged nozzles, and fittings. They are subjected to thermal cycles (stop and go) and to severe service conditions (high temperatures and high hydrogen partial pressures).MPT (Minimum pressurization temperature) is the lowest temperature at which the vessel can be repressurized after shutdown and ensures no risk of brittle failure of the containment body. The MPT is defined by fracture mechanics and calculations.
It is very important to establish minimum pressurization temperature, in order to ensure the safety of the reactors during start-ups and reactor cool down. A reasonable threshold value of the reactor’s skin temperatures is recommended by the vendor for pressurization. The establishment of minimum pressurization temperature accommodates the potential of temperature embrittlement and hydrogen embrittlement.Minimum Pressurization Temperature in Hydroprocessing Reactors
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Benze is a very serious concern if present in confined space or any other work area. In Oil refinery Benzene is mainly present in aromatics waste tanks, reactors, close drain vessels. In addition, all other confined spaces should also be taken seriously.
Its exposure can be avoided in confined spaces by;
1. Monotiring through Benzene meter or apply Lab test to analyze the atmosphere of confined space.
2. Proper ventilation will reduce the concentration in confined space. As it is heavier than air so will be settled in lower areas.Effects/Chronic:
Benzene is a well-established cause of cancer in humans.
Chronic exposure to benzene can reduce the production of both red and white blood
cells from bone marrow in humans.
Effects Acute:
Narcosis: headache, dizziness, drowsiness, confusion, tremors, and loss of consciousness.
Benzene is a moderate eye irritant and a skin irritant. -
Oxy-fuel combustion is the process of burning fuel using pure oxygen instead of air as the primary oxidant. Since the nitrogen component of air is not heated, fuel consumption is reduced, and higher flame temperatures are possible. Historically, the primary use of oxy-fuel combustion has been in the welding and cutting of metal.
Advantages:
1. The mass and volume of the flue gas are reduced by approximately 75%.
2. less heat is lost in the flue gas.
3. The size of the flue gas treatment equipment can be reduced by 75%.
4. The flue gas is primarily CO2, suitable for sequestration.
5. Low nitrogen oxide/NOXes production.
Challenges are high installation and operating costs. Installed at small-scale power plants still needs to be adopted by oil refineries. Linde Engineering has several references.
Simple process of Oxy-fuel combustion is shown by Linde.
For further details you can also visit the link. -
In addition to above, the due point of hydrocarbons is achieved at the operating conditions if we continue to decrease the amine temperature while gas temperature is on the higher side.
In cold or rainy weather when the amine suddenly drops then it is important to reduce the gas temperature as well to maintain the DT on the positive side.
Moreover, the high temperature of amine will reduce its capacity to remove H2S from the sour gas.Usman Rasheed
Operations Engineer ATU, SRU, SWT Units -
The following are the symptoms of foaming, Operation supervisor must take action or inject Anti-foam to avoid foaming when symptoms start to appear.
1. Level variations in Amine absorber or scrubber, Level transmitter, and control valve MV (Manipulated value) will show the level fluctuations.
2. The differential pressure increase in the Amine absorber.
3. Carryover of amine to downstream equipment.
4. Level and flow variations in downstream stripper/regenerator.
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