Abstract
Greenhouse gas emissions from 135 commodity chemical manufacturing processes in the United States were estimated based on benchmark process data from U.S. petrochemical manufacturing models. Total greenhouse gas emissions of the 135 processes evaluated are dominated by a small number of process types that have high emission intensities (emissions per mass of product produced) and high production volumes. These processes include facilities for manufacturing ethylene, ammonia, and chlorine. If upstream emissions associated with feedstock sources are included, well-To-gate emission estimates of the chemical manufacturing processes are affected by emission allocation and quantification methods in upstream production, with allocation methods becoming important when the feedstocks are sourced from oil and gas regions that produce multiple products. Well-To-gate emission estimates of ethylene (produced from ethane via steam cracking) and ammonia (produced from natural gas via steam methane reforming) ranged from 2.5 to 4.2 and 1.6-2.9 kg CO2e/kg production, respectively, depending on how upstream emissions are assigned to natural gas and natural gas liquids feedstocks and how methane emissions are quantified. Accurately characterizing emissions from upstream production of feedstock sources with consistent and transparent metrics is important in identifying potential emission reduction opportunities for chemical manufacturing and for evaluating greenhouse gas benefits arising from recycling of chemical products (e.g., plastics).
| Original language | English (US) |
|---|---|
| Journal | ACS Sustainable Chemistry and Engineering |
| DOIs | |
| State | Accepted/In press - 2022 |
Funding
The authors declare the following competing financial interest(s): This work was supported by the National Science Foundation (NSF) through the Center for Innovative and Strategic Transformation of Alkane Resources (CISTAR). One of the authors (Q.C.) did an internship at Gas Technology Institute (GTI) while preparing materials for the manuscript. Another author (D.T.A.) has served as chair and is currently a member of the Environmental Protection Agency, Science Advisory Board; in this role, he is a Special Governmental Employee. D.T.A. has current research support from the National Science Foundation, the Department of Energy, the Texas Commission on Environmental Quality, the Gas Technology Institute - Collaboratory to Advance Methane Science, the National Institute of Clean and Low Carbon Energy (NICE), the ExxonMobil Upstream Research Company, Pioneer Natural Resources, and the Environmental Defense Fund. He has also worked on methane emission measurement projects that have been supported by multiple natural gas producers and the Environmental Defense Fund. D.T.A. has done work as a consultant for multiple companies, including British Petroleum, Cheniere, Eastern Research Group, ExxonMobil, KeyLogic, and SLR International. Acknowledgments The authors thank Dr. Udayan Singh for helpful discussions. This paper is based upon work supported by the V. Kann Rasmussen Foundation and the National Science Foundation under Cooperative Agreement No. EEC-1647722.
Keywords
- Chemical manufacturing
- Coproduct allocation
- Greenhouse gas emissions
- Life cycle assessments
- Methane emissions
- Oil and gas production
ASJC Scopus subject areas
- General Chemistry
- Environmental Chemistry
- General Chemical Engineering
- Renewable Energy, Sustainability and the Environment
