Improvements

The Main Stack Scrubber evaluated by the Certified EIR provides for treatment of combusted CO gas from the Fluid Coker (CKR). Under the VIP Amendments, Valero is proposing to treat both CKR and Fluid Catalytic Cracking Unit (FCCU) combusted CO flue gas in a common scrubber. Accordingly, the new scrubber will be described as the FCCU/CKR Scrubber. This approach will achieve significantly greater reductions in sulfur dioxide (SO2) emissions from the CKR and FCCU than estimated in the Certified EIR. The FCCU/CKR Scrubber to be installed under the VIP Amendments will utilize regenerative amine technology, as previously evaluated by the Certified EIR, but will operate at a higher pressure. The high-pressure design will enable a new pre-scrubber which will be installed as part of the VIP Amendments to capture catalyst fines and coke fines (primarily ash). This will allow the scrubber system to provide for the equivalent control of particulate emissions and eliminate the need to operate the existing electrostatic precipitators (ESPs). Additionally, the pre-scrubber will remove about half of the sulfur trioxide (SO3) which is not removed as effectively by the ESPs. As described in the Certified EIR, the amine solution will be regenerated in another process vessel allowing for the solution’s reuse.

The Benicia Refinery’s two existing PS furnaces, F-101 and F-102, cannot operate at the higher pressures necessary for the FCCU/CKR Scrubber to be installed under the VIP Amendments. Therefore, F-101 and F-102 will be shutdown and replaced by two new, high-pressure furnaces, to be designated F-105 and F-106. F-105 and F-106 will use selective catalytic reduction (SCR) for NOX emissions control. The gas stream entering the SCR will have a higher particulate load than is typical for sources controlled by SCR technology. As discussed below, Valero will use an SCR design that will ensure that the SCR catalyst will not be contaminated by the particulate matter (PM) in the gas stream.

PM emissions downstream of F-105 and F-106 will be controlled by the pre-scrubber and the regenerative amine scrubber. The existing PS furnaces F-101 and F-102 will be decommissioned. Since F-101 and F-102 will no longer be used and PM emissions from F-105 and F-106 will be controlled by the pre-scrubber, the existing ESPs will not be needed and will be turned off to reduce electrical power demand.

The FCCU/CKR Scrubber will exhaust through a new dedicated stack. An additional small source, the F-103 furnace, which currently exhausts through the Main Stack will continue to exhaust through the Main Stack. After implementation of the VIP Amendments, only the two emergency tail gas incinerator vents from the refinery’s Sulfur Recovery Units (SRUs) and F-103 will continue to be routed to the existing Main Stack.

The Certified EIR included a new refinery fuel gas (RFG) fired PS Helper Furnace. In the current configuration of the VIP Amendments, this furnace is not needed and will not be installed.

The currently approved VIP Use Permit provides for an increase in production of an existing hydrogen unit (H2U) and installation of a Pressure Swing Adsorption (PSA) Unit for improved hydrogen purity. In order to capitalize on improved energy efficiency inherent in more modern technology, Valero now plans to shut down one of the two trains of the existing H2Us and construct a new H2U. Benefits of the new H2U include greater system efficiency, decreased emissions per unit of hydrogen produced, and decreased consumption of commercial natural gas in favor of consuming RFG as the feed stock for producing hydrogen.

By consuming RFG, the new H2U will improve the refinery’s fuel gas balance, which will reduce the incidences of excess fuel gas, and thus, reduce flaring. In addition, the increased energy efficiency of the modern H2U will reduce carbon dioxide (CO2) emissions and GHGs when compared with the previously planned expansion of one train of the existing hydrogen unit evaluated by the Certified EIR. At this time, Valero does not plan to add the previously approved PSA Unit to the remaining operational H2U train. Omitting this project component will reduce the electrical demand of the VIP Amendments, thereby reducing indirect GHG emissions relative to VIP.