The Operation of Refinery Hydrogen Systems

The refinery hydrogen distribution system usually comprises a set of hydrogen main headers (pipelines) working at different pressures and hydrogen purities. Many makeup and recycle compressors drive the hydrogen through this complex network of consumer units, on-purpose production units, and platformers (see Figure 1a). On-purpose hydrogen plants generate high purity hydrogen at different costs while net production units are platformers generating low purity hydrogen as a byproduct. Hydrogen streams with different purities, pressures and flow rates coming from make-up hydrogen plants and platformers are supplied to multiple consumer units...

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Flare Gas Recovery (FGR) to Minimize Wastes and Economical Benefits

Abstract One of the safe and pressure relieving systems in oil and gas refineries as well as petrochemical complexes, is the relief header with the flare stack being the last component. In this network all the excess gases are collected and sent to flare stack to be burnt. A great amount of these gas mixtures has a high heating value and in some cases it can even be used as the raw material forvarious units. It is clear that burning this gas mixture in flare stack causes environmental problems like air and noise pollution and also is a financial waste. In this paper a step by step approach and calculations are given to calculate and discuss...

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Coriolis gas flowmeters

Recent advances in the development and performances of Coriolis meters have meant that the measurement of the mass flow rate of gases, such as natural gas for custody transfer applications, is now a reality. International standards This has been reflected by the large acceptance of this technology within the natural gas industry. As an example, Micormotion has supplied 5,000 Coriolis meters for natural gas applications in the last 3 years. This industrial acceptance motivated ISO to develop a standard through the ISO Technical Committee—ISO Standard TC30/SC12. In addition to this ISO standard, there is also an engineering technical...

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OBQ and ROB

ON BOARD QUANTITY (OBQ): All the oil, water, sludge and sediment in the cargo and associated lines and pumps on a ship before loading a cargo commence. (this term may not apply to product movement). QUANTITY REMAINING ON BOARD (ROB): All the oil, water, sludge and sediment in the cargo tanks and associated lines and pumps on a ship after discharging a cargo has been completed, excluding vapour but including clingage. (this term may not apply to product movements) Determine the OBQ/ROB for Liquids as follows: (1)    By measurement determine the depth of liquid in each tank. Measure-ments should be taken at as many points as possible to ascertain if the liquid covers the tank bottom. (2)    Where there is a sufficient depth of liquid determine its temperature....

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Basic Concepts in Data Reconciliation

1.1 Process Measurements Measured process data inevitably contain some inaccurate information, since measurements are obtained with imperfect instruments which have their own accuracy. In addition, signal transmission, power fluctuation, improper instrument installation and miscalibration are other sources of measurement errors. It is assumed that any observation is composed of a true value plus some error value. This indicates that a measurement can be modeled as: y = x + e           (1.1) where y is the observed value of the raw measurement, x is the true value of the process variable, and...

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Trading Strategies for Crude Futures

Crude oil futures traders can match their trading strategy with their risk tolerance. Comstock Images/Comstock/Getty Images Crude oil futures are known for their high volatility and wide price swings. It’s not unusual for crude oil futures to trade down in the morning but close at a new high when the trading day ends. Traders use several popular strategies that take advantage of crude oil’s unpredictable nature. By analyzing the crude oil futures market, traders select the tactics they believe will result in a profit before the crude oil futures contract expires. Buy and Hold Trading Strategy Buy and hold is probably the best known...

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