Category: Process Troubleshooting

Corrosion Inhibitor

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To clean up amine, the rate of particulate generation must be slowed and the iron sulfide already in the amine filtered out. Reducing corrosion rates is the way to do this. In one Midwestern refinery, the amine solution was thick with iron sulfide. Within two weeks, the solution was restored to a light gray by …

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Cleaning Up Amine

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The iron sulfide particulates circulating in a dirty amine system have built up from a combination of factors. Foremost among these is inadequate filtering. There are three common types of filters: rotary precoat filters, cartridge filters, and stacked paper plates. In practice, paper plates are best. In particu­lar, Sparkler stacked filters are easy to maintain. …

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Dirty Amine Ruins Operation

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Running a sulfur recovery operation with dirty amine is analogous to deficit spending. You are borrowing against the future, but the day of reckon­ing will surely come. The insidious aspect of circulating dirty amine is its erosive nature. Carbon steel is corroded by clean amine. However, the sulfide products of corrosion stick to the metal …

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Dirty Amine

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Symptoms of a dirty, corrosive amine system are: Carry-over of amine from the scrubbers. Dilution of the amine system with water due to reboiler leaks. Plugging of instrument taps with particulates in the amine. Loss of amine to the sewer because of leaks. Rich amine leaking into lean amine in the cross exchanger. Problems related …

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Amine regeneration flowsheet

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Amine regeneration flowsheet

Figure 4-1 is a process flowsheet showing how amine solution is circu­lated to various refinery scrubbers to absorb H2S. The lean amine chemically combines with H2S (and unavoidably some C02) in the scrubbers. The resulting rich amine is stripped in the regenerator. Released acid gases (H2S and C02) are charged to the sulfur recovery plant. …

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Retrofitted combination tower to save energy

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Retrofitted combination tower to save energy

The hot coke drum vapors are a valuable source of high-level heat. This energy, which is partially recovered in the combination tower heavy gas-oil pumparound section, can be used for generating steam, preheating coker feed, or reboiling a gas plant. The higher the temperature level at which this heat is made available for recovery, the …

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Explosion-Proof Trays

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Explosion-Proof Trays

Coker fractionators are subject to damaging pressure surges due to accidental flashing of water. The pressure surges results in the tray decks “ripping” away from the tray support rings. Actually, the tray decks are not ripped away from the support ring. Inspection of damaged trays indicates the decks have been bent at the ring. The …

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Combination Tower

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Combination Tower

A delayed coker combination tower is similar in design and function to an ordinary crude distillation tower; heat is removed and products are fractionated. Referring to Figure 3-1, four products are made: wet gas, unstabilized naphtha or wild gasoline, furnace oil, and heavy gas oil. The most common problem encountered in the combination tower is …

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Vapor Line Restriction

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Coke that builds up in the coke drum overhead vapor line is responsible for most of the back-pressure incidents. Operators find that tearing the insulation off these lines slows the rate at which coke deposits. A better method is to inject a heavy slop oil quench, as shown in Figure 3-4, into the vapor line …

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Wet Gas Compressor

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Vapors from the coke drum must pressure their way through to the combination tower reflux drum. Any restriction to their flow will increase the operating pressure of the coke drum. To avoid exceeding the coke drum relief valve pressure, some operators vent the reflux drum to a flare. This makes it appear as if the …

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