Published December 2023
Ethylene is the largest-volume basic petrochemical. It is produced primarily by steam cracking of hydrocarbons (naphtha, gasoil, ethane and liquefied petroleum gas [LPG]) and is utilized to produce a spectrum of chemical intermediates. Ethylene consumption has been increasingly driven by its demand in the emerging countries and the consumption has increased at an average rate of approximately 4% per year over the past decade.
Ethylene production is one of the three largest CO2 emitters in the chemical industry; the other two are that of propylene and ammonia. Conventional cracking generates roughly 1-1.8 metric tons (t) of CO2 for every metric ton of ethylene produced. Globally, that amounts to more than 260 million metric tons (MMt) of CO2 emissions per year.
This report provides a comparison of three possible routes to decarbonize ethylene production by cracking of naphtha. The three routes analyzed are
- Addition of a conventional amine unit to capture CO2 from flue gas
- Conversion of methane to blue hydrogen using autothermal reforming (ATR) technology, and powering the gas furnace with hydrogen fuel
- Oxy-fuel combustion of methane in the cracking furnace, so that pure CO2 is obtained in the furnace flue gas without the need of amine separation
The analysis is based on the production of 1 million metric tons per year (MMt/y) of polymer-grade ethylene. Wide range naphtha (WRN) is the feed, and all three technologies employ a front-end de-propanizer configuration. Though the quantitative results will differ for other feeds/configurations, directionally the analysis of relative merits/demerits will be still valid.
The economic snapshot (capital and production cost) is provided for each process for the first quarter of 2023, on US Gulf Coast (USGC) location basis and in English units. The accompanying iPEP Navigator, an excel-based interactive module (available with the electronic version of this report), allows the user to compare the processes in different regions of interest, times and units (English or metric).
The analysis is based on information given, by the technology providers, in open literature (such as patents or technical articles) or in-house generated data (e.g., HYSYS simulation and equipment cost estimation). While this assessment may not reflect the actual plant data fully, we do believe that it is sufficiently representative of the process and process economics within the range of accuracy necessary for economic evaluations of a process design.