El Segundo Refinery Fire

There has been muted press output on the El Segundo refinery fire the same news line being copied to many reports.

The LA Times quoted “the fire broke out in the refinery’s Isomax complex, which converts gas oil into higher-value products like jet fuel”.

The Isomax unit is a hydrocracking process that cracks heavy gas oils, mainly vacuum gas oil, to lighter products which include LPG, naphtha, jet and diesel. The unit has some flexibility to produce more or less naphtha and jet fuel by changing the severity of the cracking process. It would appear from press reports that Chevron were maximizing jet fuel production of the hydrocracker, which is highly likely, based on the refinery configuration and that the refinery was the main supplier to LAX.

The El Segundo refinery is a fairly complex refinery of about 269 kbd processing capacity (CDU cap). It has the following units according to the Oil and Gas Journal

1. CDU                 260 kbd

2. VDU                 160 kbd

3. Delayed Coker            69 kbd

4. Fluid Catalytic Cracker  66 kbd

5. Hydrocracker               49.5 kbd

6. Alkylation                      30 kbd

7. Isomerisation              20 kbd

8. Jet Hydrotreater          37 kbd

9. Diesel Hydrotreater  46 kbd

The crude feed to this set up would need to be fairly heavy as the VDU/CDU ratio is about 0.59 which would require a crude equivalent like Arab Heavy. Some reports that the refinery runs Alaska North Slope, local San Joaquin crude as well as imports. Without doubt this is a fuels refinery with a high jet fuel make.

The unit that failed is a Chevron own design Isomax which is one a of a family of hydrocrackers form this stable. There a numerous versions ,all of which are licenced by Lummus. This is one of the earlier versions and is two stage with recycle of the first stage bottom products. It is possible to achieve almost recycle extinction. The heavier the feed the greater the temperatures and pressures and the higher consumption of hydrogen. Indicative parameters for temperature and pressure are:

Temperature 260-480 deg C

Pressure 35-200 bar

Hydrogen Consumption 100-2400 scf/b

My guess would be that Chevron would have been operating in the higher end of the temperature and pressure range. One of the problems with hydrocrackers is hydrogen embrittlement of steel, which is more pronounced as the temperature and pressure increases. Special steels are required for such equipment but occasionally failures can occur. My best guess is that after looking at the imaging the fire appears to have been around the hydrogen separation. The first stage reactors(2 off) on the right-hand side appear to be undamaged. On the right hand side the fractionator appears to be intact, along with other units which are possibly the naphtha /LPG separator.. Water is being sprayed into the centre of the image which is where the hydrogen separator is likely to be. However, the blackened structure which is still being cooled looks to be substantially intact.

Looking at other images of the fire suggests that the fire was controlled and allowed to burn off the flammable hydrocarbons. Actual damage appears to be limited and that adjacent structure were not severely damaged.  I would say the firefighters did a good job and preserved most of the plant, in spite of the fierce fire. I would guess that there was a leak of hydrocarbons that were under high pressure and temperature. An ignition source would not be required as jet-kerosine has an auto-ignition points of about 210 deg C, and all the leak had to fire was a source of oxygen and ignition would be instantaneous. There is no realistic was of extinguishing such a fire. Like an oil well fire the source of the fuel has to be stopped. In this case the feed pumps for feeds and hydrogen would be shut in and the reactor columns would then depressurize and vent to atmosphere and as the fuel was used up and the pressure subsided the fire would naturally calm and eventually run out of fuel. The important thing is to keep the equipment cool.

I would not rate this as a total loss for the Isomax unit. Most likely it could be repaired without too much cost. The refinery throughput will be affected, quite significantly as this was a large process unit. The biggest impact will be on jet production and to a lesser extent on gasoline and diesel. The biggest hassle will be the inquiry and adverse publicity. Both Phillips(Wilmington (13* kbd) and Valero(Benicia 138 kbd) are planning to close a refinery each in California. Chevron have two refineries in California, the other refinery being in Richmond CA (244 kbd). Other US refineries include Pascagoula Mississippi 375 lbd, Pasadena Texas 112 kbd, and Salt Lake City Utah 54 kbd.

Will Chevron throw in the towel on El Segundo. I doubt it at this stage, but increased pressure from the left wing administration of Gavin Newsom could tip the balance.

I will go into more detail on hydrocracking after I have covered fluid catalytic cracking.