ConocoPhillips - E-Gas Technology, Gasification Solutions for Coal and Petroleum Coke

ConocoPhillips develops and implements cutting-edge technologies that help oil and gas producers, refiners and manufacturers meet their desired objectives. The company's research facilities and longstanding history of innovation provide technology solutions for vehicles, oilfields and energy systems worldwide.

ConocoPhillips' downstream technology solutions help improve refining and production efficiency, while meeting the highest levels of safety and environmental standards. One of the company's key solutions include gasification technology.

Power generation with gasification

The ConocoPhillips E-Gas™ Technology is proven as one of the cleanest, most efficient commercial processes for converting coal or petroleum coke into a synthesis gas (syngas) as fuel for power generation. The combination of gasification and gas turbine power plant facilities is referred to as integrated gasification combined cycle or IGCC. The feedstock, which is typically coal or petcoke, is converted to syngas in the gasification unit. The syngas is cooled, processed to remove impurities, and provided as fuel to the gas turbine generators. This processing removes more than 99% of the sulfur components from the coal and has the capability to enable reduction of CO2 emissions to a level below a natural gas combined cycle power plant and further. In an IGCC application the impurities are removed before the fuel is delivered to the turbine making the removal less costly than conventional coal plants that attempt to remove impurities after combustion.

With more than 25 years of proven commercial experience in integrated gasification combined cycle application, our technology provides a highly efficient, environmentally superior, and competitive based-load option. The E Gas Technology has processed over five million tons of coal and petcoke at the Wabash River IGCC Plant, operating exclusively on petcoke since August 2000. The ConocoPhillips E-Gas team has extensive experience with all areas of an IGCC project design from gas treatment to combustion turbine selection. This invaluable operating know-how is reflected in the designs for the next generation of E-Gas facilities.

Utilising our E-Gas gasification process, ConocoPhillips is leading the way toward viable and cost-effective clean energy production through the development of an IGCC Gasification Project adjacent to the Sweeny Refinery in southeast Texas. The use of this technology as an integrated gasification combined cycle (IGCC) application will make this plant one of the cleanest fossil fuel power plants in the world. The project as designed will significantly minimise emissions of all criteria pollutants, and utilisation of carbon capture technology will significantly reduce greenhouse gas emissions by capturing and storing a CO2.

Substitute natural gas production

Another key product that can be produced in plants using E-Gas Technology is substitute natural gas or SNG. This option is becoming increasingly important as nations around the world look to long-term supplies of gas that can be derived from domestic sources of coal or petcoke. Since SNG has essentially the same quality as produced natural gas, SNG can be used to heat our buildings, generate electricity or as chemical plant feed stocks.

The process involves several steps including gasification, water shift, acid gas removal (AGR), and methanation. Gasification produces syngas which contains carbon monoxide (CO), hydrogen (H2), and carbon dioxide (CO2) which are the building blocks for SNG. Additional hydrogen is created by reacting water with carbon monoxide to produce hydrogen and carbon dioxide – this is referred to as a water shift reaction. This step produces the proper hydrogen to carbon monoxide ratio required for the methanation reaction. Prior to entering the methanation unit, the syngas is cooled and processed in an AGR unit to remove most of the sulfur containing compounds along with the CO2. The captured CO2 can be injected and stored in geologic formations or used in enhanced oil recovery (EOR) projects. This produces a sweet clean synthesis gas as required for the methanation reaction. Methanation is accomplished by reacting carbon monoxide and smaller amounts of carbon dioxide with hydrogen in a catalytic assisted reactor. The product is a high quality SNG ready for pipeline transport.

ConocoPhillips is applying its E-Gas technology in the development of the Kentucky NewGas project. This project would use Kentucky's abundant coal reserves to produce 60 – 70 billion cubic feet of natural gas annually. The project would recover over 99% of the sulfur and is designed to be carbon storage ready.

Coal-to-chemicals

Feedstocks for chemical plants can be generated using gasification of coal or petcoke in lieu of using higher cost natural gas or petroleum products. The key ingredients for these feedstocks are hydrogen and carbon monoxide which are the main components produced during the E-Gas gasification process. The proprietary two-stage E-Gas Technology can be customised to produce varying amounts of these components depending on the need and the end product.

A wide range of chemical products can be derived from syngas with additional downstream processes, including ammonia, urea, methanol, and acetic acid. Ammonia and methanol based products are the most common applications for chemicals derived from gasification.

Utilising coal or petcoke to produce chemical feedstocks can reduce the price volatility associated with purchasing natural gas or petroleum processed feedstocks. ConocoPhillips E- Gas technology has been proven to handle a variety of coals and petcoke to reliably produce the syngas needed for this type of service.

Transportation fuels

Transportation fuels can also be derived from syngas. The gasification process and equipment for this option is the same as required for chemical feedstock production. Transportation fuels can be generated from syngas using either a Fischer-Tropsch or methanol conversion technologies. These processes can produce diesel, oils, olefins, gasoline, naptha, jet fuel among other items. The difference is that Fischer-Tropsch converts the syngas to liquid, usually diesel or naptha, while methanol is converted to olefins or gasoline. These technologies become increasingly attractive as crude prices remain high.

Refinery polygen

In a refinery setting, gasification can provide a variety of products that are useful including, steam, power, hydrogen, or SNG - depending on the need. Hydrogen is one the most common gases used in refineries. Hydrogen is typically generated from steam methane reformers (SMRs) using natural gas as the feed. This process produces hydrogen along with CO2 which is typically vented. Hydrogen is used to remove impurities in the crude - mainly sulfur compounds before further processing. Most refineries produce petroleum coke as a residual from processing crudes, and then sell the petcoke to marketing companies that resell or export this fuel. With gasification, this petroleum coke can be processed and returned to the refinery as fuel or hydrogen.

Petcoke at a refinery has advantages including low ash content, high heating value, and close proximity to the gasification plant thereby reducing transportation costs. The economics of generating hydrogen or natural gas are based on petcoke pricing which is typically more stable than natural gas supplies. The power and steam produced from the gasification facility can be integrated with the refinery to reduce the amount of fuel needed. In addition, the gasification process combined with carbon capture can lower the overall carbon footprint for a refinery.

Click here to see a Look Inside the process.

www.conocophillips.com.