CHEVRON PRODUCTS COMPANY - Issuance of an Alteration Authority to Construct and Permit to Operate, (Air District Application 714498).

CHEVRON PRODUCTS COMPANY - Issuance of an Alteration Authority to Construct and Permit to Operate, (Air District Application 714498).

Chevron has submitted an Accelerated Permit application under Air District Regulation 2-1-302.2.3 to alter its five power plant boilers (S-4129, 5-4131, S-4132, S-4133, and S-4135) and to alter its Fluidized Catalytic Cracking Unit (FCCU, S-4285) so that they can operate their FCCU without its Power Recovery Turbine (PRT). 5-4285 converts high-boiling point hydrocarbon fractions of crude oil into gasoline and other petroleum products and consists of a reactor vessel and a regenerator vessel. The conversion process is achieved through a chemical process that occurs in the reactor vessel that incorporates the use of heat and a catalyst to break up, or "crack," long-chain hydrocarbons into smaller-chain hydrocarbons. Large paraffinic hydrocarbon molecules break up, or "crack," into smaller molecules that flow overhead from the reactor vessel to a fractionator for separation into saleable products. The spent catalyst that participates in the cracking reaction falls to the bottom of the reactor vessel and is steam stripped as it exits the reactor bottom to remove absorbed hydrocarbons. The spent catalyst from the reactor vessel is then routed to the regenerator vessel where the carbon deposited on the catalyst from the cracking reactions is combusted off with preheated air supplied by the Main Air Blower (MAB). The hot regenerated catalyst from the regenerator vessel then returns to the reactor vessel for another cracking cycle. The flue gas from the regenerator vessel is routed to the 3rd stage separator vessel where cyclones within the 3rd stage separator vessel remove the larger catalyst fines entrained in the flue gas. The larger catalyst fines gravity flow to the fines transfer vessel and are collected in the fines transfer vessel's fines hoppers and are transferred off-site. During typical operation, a portion of the flue gas from the 3rd stage separator vessel is routed to the PRT and expander where the pressure and temperature in the flue gas are reduced to generate shaft horsepower which is used to drive the MAB. The flue gas from MAB, and the remaining portion of flue gas from the 3rd stage separator vessel are routed to the Waste Heat Steam Generator (WHSG) where the flue gas is cooled prior to entering the electrostatic precipitator (ESP). The ESP (A-14) which abates S-4285 removes particulate matter entrained in the flue gas. The flue gas exiting A-14 is routed through an economizer to recover heat from the flue gas and preheats the feed water for the refinery's steam generating equipment before exiting out the stack. The MAB can be powered by the PRT, the steam turbine and/or the motor-generator. The stator vanes and rotor in the PRT were recently damaged and need repairs rendering the PRT inoperable. As discussed above and during typical operation, the PRT provides most of the power to the MAB. When the PRT is not operating, the steam turbine which provides power for start-up and lets down high pressure steam for electrical power recovery, must operate with the motor generator which turns the remaining horsepower from the PRT and steam turbine into electricity to fully power the MAB. Since the FCCU will be unable to operate the PRT, the FCCU will need to utilize steam turbine capacity, thus increasing steam consumption by about 2.88 million pounds per day. The increase in steam consumption at the steam turbine will be made up by two or more of the five power plant boilers which collectively supply steam to the refinery. To ensure Chevron's proposal to operate the FCCU without the PRT is an alteration per 2-1-233, the temporary Permit to Operate (TPO) that was issued on September 19, 2024 which is valid until March 18, 2025 imposed emission limits (daily, annual, and combined) for all criteria air pollutants and fuel usage limits (daily, annual, and combined) for each one of the five power plant boilers from data Chevron provided to the Air District as part of Regulation 12-15 for calendar years 2016-2023 to ensure they operate within the confines of those emission and fuel usage limits and are not modified per Air District Regulation 2-1-234.

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