6.26 Vacuum Truck at Refinery, Marine, Bulk Terminals - Petroleum Product

Category 2224

6.26.1 Introduction

Categories 2224 accounts for fugitive organic emissions from the operations of vacuum trucks at refineries, marine, and bulk terminals.

A vacuum truck is a transportable, truck-mounted, industrial vacuum system designed to load materials into the truck’s containment vessel. Vacuum trucks are capable of loading different types of materials (either pneumatically, by external pump or by gravity feed) into their barrels under a variety of conditions. Emissions are comprised of volatile organic compound (VOC) emissions.

6.26.2 Methodology

Category 2224 is considered an area source category since it covers facilities / emission sources that are not directly permitted by the District, and hence not systematically cataloged. Emissions for area source categories are determined using the formula:

Current Year Emissions = Base Year Emission X Growth Profile, and,

Base Year Emission = Throughput X Control Factor X Emission Factor

where,

• throughput or activity data for applicable base year(s) is determined using a top-down approach (e.g. state-, national-level data);
• emission factor is derived from general literature, specific literature and reports, and/or source testing results provided by Air District staff;
• control factor (if applicable) is determined by District and state rules and regulations in effect;
• and, historical backcasting and forecasting of emissions is based on growth profiles as outlined in the Trends section of this chapter

More details on throughput, county distribution, emission factors and controls is provided in the following subsections. Vacuum truck emissions are calculated based on throughput and source test data.

(a) Activity Data / Throughput

Throughput data, when available, is obtained from refinery records. Source test data is taken from monitoring measurements during field studies. Because of the wide variation in test results and because most facilities do not closely track quantities of materials moved by vacuum truck, estimates of emissions and emission reduction for vacuum truck involve significant uncertainty. To determine quantities of materials moved in each category, data was taken for one refinery and scaled for other facilities to arrive at the total.

(b) County Distribution / Fractions

With major refinery, marine, and bulk terminal presence, Contra Costa and Solano counties have the largest vacuum truck operations of all the San Francisco Bay Area counties. This is primarily due to the presence of refineries at these two counties. When disaggregated by county, Contra Costa county accounts for 83 percent while Solano county accounts for the remainder of vacuum truck operations in the Bay Area.

(c) Emission Factors

Emission factor is derived from District source test data.

(d) Control Factors

To limit and reduce organic compound emissions from this category, District’s Regulation 8, Rule 53, Vacuum Truck Operations Rule ²⁶⁸. The rule establishes an emission limit that applies at the vapor exhaust outlet of the vacuum truck or associated equipment. The rule also establishes a limit for vapor leads and for liquid leaks from vacuum truck equipment.

(e) Speciation

This source category reports Total Organics Gas (TOG) emissions. Ethanol is a reactive Volatile Organic Compound (VOC) and all ethanol emissions are considered under Reactive Organic Gases (ROG). Hence the ROG: TOG ratio is equal to 1.

6.26.3 Changes in Methodology

There are no changes in the methodology to estimate emissions in the current base year inventory compared to the previous base year inventory (year 2011).

6.26.4 Emissions

A summary of emissions by category, county, and year are available via the associated data dashboard for this inventory publication.

6.26.5 Trends

Projected growth for all refinery related categories was based on the even extrapolation of California Annual Operable Atmospheric Crude Oil Distillation Capacity reduction from 2010 to 2020, i.e., it’s assumed a 0.67% decrease annually from 2021 to 2040. The data used in the extrapolation is taken from US Energy Information Administration website²⁶⁹. The decrease is primarily driven by the shift to further increase fuel efficiency of vehicles through the U.S. Department of Transportation’s National Highway Traffic Safety Administration Corporate Average Fuel Economy (CAFÉ) standards as well as steady transition to electric vehicles and other alternative fuels (hydrogen fuel cell and others) in the California market.

6.26.6 Uncertainties

For area source emission factors, the main uncertainty in the updated methodology arises from the use of emission factors for certain categories that remain constant over several decades although technological controls may have been applied at facilities. Additionally, the emission factors themselves are seldom verified and validated against measurements, in part due to the difficulty in measuring fugitive emissions from area sources.

6.26.7 Contact

Author: Tan Dinh

Reviewer: Abhinav Guha, Yuan Du

Last Update: November 06, 2023

6.26.8 References & Footnotes