Gasification/IGCC to improve refinery operations
Gasification and IGCC in refineries is discussed in light of increased attention to CO2 emissions and environmental performance.
Brett P. Goldhammer, Adrienne M. Blume and Thomas W. Yeung
Hydrocarbon Publishing Company
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To refiners, changes and challenges are constant. After overcoming the obstacles of fuel reformulations and dismal profit margins in the 1990s, the industry is now facing a growing number of critical issues at a time of surging oil prices. Two primary concerns involve securing steady fuel supplies and complying with increasingly stringent environmental requirements, especially those related to climate change. Six key areas that refiners must address include:
• Upgrades and revamp projects to produce high volumes of ultra-clean fuels
• Refinery-petrochemicals integration and non-traditional petrochemicals production methods to secure petrochemicals supplies
• Output of valuable products from flare gas (which is produced both upstream and downstream) to combat GHG pollution
• Clean fuels and chemicals production from biofeedstocks processed at refinery sites
• Energy efficiency improvements to reduce CO2 ‘make’
• Development and implementation of integrated gasification combined-cycle (IGCC) technology to provide clean and efficient onsite supplies of power and steam.
The advancement and application of gasification technologies to shave energy use and abate CO2 emissions in hydrogen production, cogeneration (with IGCC), resid processing and second-generation biofuels applications has become an attractive option for refiners seeking to meet these new challenges. Furthermore, the opportunity to apply CO2 capture and sequestration (CCS) techniques to each of these areas provides additional incentive to consider this technology.
Political pressure mounting
With rising political pressure throughout the world to tackle global warming, CO2 reduction has been pushed to the top of the list in the near-term. Over the past year, both the USA and Europe have enacted new policies concerning CO2 and GHG emissions across several industrial sectors, including petroleum refining. The European Commission (EC) issued a proposal on 31 January 2007 to slash CO2 emissions from fuel production, refining, transport and usage by 10% (or 500MM mt) over the period of 2011-2020, in an effort to adhere to Kyoto Protocol requirements. In the USA, energy legislation signed into law on 19 December 2007 provides the USA’s Environmental Protection Agency (EPA) with $3.5MM in fiscal 2008 to create a registry that will be used by refineries and other industrial plants to report emissions of greenhouse gases. The bill mandates that the EPA develop the reporting system within nine months, and establish a final rule on GHG reporting within 18 months. The law calls for emissions reporting at ‘appropriate thresholds in all sectors of the economy’ as determined by the EPA, meaning that both upstream and downstream energy ventures will be required to report emissions of CO2 and other GHG pollutants.
On 6 December 2007, the California Air Resources Board (CARB) in the USA agreed to require refineries, power plants, manufacturing facilities and cement kilns in the state to report emissions of CO2, NOX, and methane starting in 2009. These plants account for 95% of California’s industrial emissions. Initial reporting will not require verification by an outside company. However, future reports will be audited.
Legislative activity throughout the world has a clear effect on refiners. Every refinery expansion, process configuration and new unit that is installed must be done with consideration of the previously mentioned issues. As a result, technology developments are now focused on providing strategies for increased energy efficiency and GHG abatement.
Gasification: logical solution
Meeting the challenges of securing fuel supplies and improving environmental performance can be very complicated on a refinery level, especially since the increased production of clean fuels increases H2 demand. Meeting these requirements requires a large capital investment and a great deal of energy, which results in increased CO2 emissions. Innovative processing schemes involving increasingly heavy crudes, refinery residues and, alternatively, biomass will also increase energy requirements in the refinery. Furthermore, the basic need for clean, cost-effective, efficient power is present in every refinery operation throughout the world. As a result, efficient power generation and use is viewed as one of the most important concepts in the hydrocarbon processing industry.
Refiners can take advantage of these situations by integrating large, efficient gasification plants into their facilities to cheaply cogenerate their own power and steam as well as a significant supply of hydrogen gas by processing a variety of low-value hydrocarbon streams such as coke, coal, resid, waste, biomass, etc. Finally, the potential to capture and sequester CO2 within the gasification process is very appealing.
Hydrogen supply can be a major issue in hydrocarbon processing. Many processing units throughout a typical oil refinery use large volumes of hydrogen gas, which can become a great financial burden. Furthermore, the trend to supply increasingly cleaner fuels with lower sulphur and contaminant levels has generally increased hydroprocessing capacity and, consequently, hydrogen demand throughout the world. Gasification can be a viable source of hydrogen production from a variety of feedstocks. It is also possible to specifically design a gasification unit to produce high-hydrogen-content synthesis gas (syngas) when that product is desired.
Cogeneration and IGCC
Oil refiners have traditionally been sceptical about constructing power plants on site due to their limited electricity requirements (usually about 60 MW for a standalone refinery) and because of the capital intensity of such projects1. The recent trend towards CO2 cap legislation, energy efficiency improvements and the liberalisation of the electricity market, combined with an increasing need to dispose of refinery waste streams, has led many refiners to reconsider their options.
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