CO2 Capture from Hydrogen Production

Industrial Gases

CO2 Capture from Fossil Fuel Based Hydrogen Production

The demand for hydrogen (H2) is rapidly increasing in chemical and petrochemical industries due to the continued growth in demand for low sulfur fuels and to support unconventional oil sands development. Increased demand for hydrogen, while good for the industrial gas industry, leads to increased concern about CO2 emissions, as most hydrogen is produced using methods that emit CO2. This makes the capture and storage of CO2 from hydrogen production an interesting option for the reduction of CO2 emissions.

There are several ways to reduce greenhouse gases emitted from fossil fuel based plants including CO2 capture. Today, the principal technology used for CO2 capture from hydrogen plants is based on chemical absorption, but this process requires large amounts of energy thereby reducing its environmental benefit. And it is costly, currently in the range of EUR 30–40/ton of CO2 captured.

Union Engineering, a world leading supplier of CO2 technology, has developed Flash CO2 (Patented), an innovative way to capture CO2. The technology significantly reduces the cost of CO2 capture from fossil fuel based hydrogen production and enables liquid CO2 to be produced at a direct operating cost of around EUR 20/ton, making CO2 capture from hydrogen production significantly more attractive.

The Process
A typical hydrogen plant uses a PSA (pressure swing adsorption) for purifying the hydrogen product. Union Engineering’s
FlashCO2 technology was developed to provide an attractive solution for the capture of CO2 from the medium-rich CO2 off-gas being purged from the PSA. By utilizing an innovative process of combining conventional physical absorption by means of chilled methanol (MeOH) and liquefaction technologies, the FlashCO2 process eliminates the requirement for steam stripping and keeps power consumption at an attractive level.

Utilizing the PSA off-gas means that the FlashCO2 is an end-of-pipe solution, that is, it does not need direct integration with the
hydrogen plant, which significantly reduces the risk of unwanted interruptions in hydrogen production.
In addition to the environmental benefits that FlashCO2 technology offers in terms of carbon capture and storage in the longer
term, this technology can be used today to produce food grade CO2 for the merchant CO2 market. Despite the fairly low CO2 concentration in hydrogen PSA off-gas, the integrated double loop design of the FlashCO2 technology makes the plant capable of producing food and beverage grade CO2 at costs competitive with more conventional CO2 sources, such as ammonia and bioethanol production plants.

A FlashCO2 Plant in Chile 
Recently, Union Engineering installed a FlashCO2 plant with Indura SA (www.indura.net), a leading industrial gases company in Chile. In early 2005, Indura realized they needed to replace their existing CO2 plant, which was based on combustion of fossil fuel for CO2 production, with a more modern and sustainable production plant. Instead of burning fossil fuel only for production of CO2, Indura wanted to utilize a by-product energy stream for their new CO2 processing plant. The obvious choice, both in terms of location and attractiveness of the source, was PSA off-gas from a hydrogen production plant with Chile’s major refinery ENAP, in Concepcion.

After having evaluated a range of existing amine-based technologies, Indura decided Union Engineering’s FlashCO2 technology
was the best choice for their new food and beverage grade CO2 processing plant. In addition to being the most attractive solution in terms of total cost of ownership, the FlashCO2 plant provided other important benefits that influenced Indura’s choice. For example, as an end-of-pipe solution, Indura was able to install the plant outside the refinery boundary thereby avoiding the need to follow ENAP’s strict refinery procedures.