The amount of CO2 in our atmosphere has risen drastically since preindustrial times. Cities produce about 80% of all greenhouse gas emissions such as CO2. In recent years, governments have actively tried to put a stop to global warming. Tighter environmental regulations and restrictions force companies to look for new, more environment-friendly technology that improve air quality.
The industry is advancing technological solutions to mitigate climate change and to reduce carbon dioxide emissions. One way to prevent the release of CO2 into the atmosphere is with carbon capture and storage (CCS). Sulzer offers pumps and mass transfer equipment that can be used in all stages of the CCS chain. The company’s technology thus helps limit the adverse impact of CO2 on the environment.
Capturing Emissions Where They Emerge
A carbon capture and storage (CCS) project in the USA aims to reduce the carbon dioxide (CO2) emissions of a fossil fuel power plant by 90%. Sulzer provides the mass transfer technology required for the capturing process. The company’s solutions help customers increase the efficiency of their equipment and lower their costs.
After China, the USA is the second-highest emitter of greenhouse gases (GHG) in the world. Most GHG emissions in the USA stem from power generation. The WA Parish power plant—located in Thompsons, TX, USA—is the largest fossil fuel plant in the USA and one of the largest CO2 emitters. CCS is one of the technologies that can help mitigate GHG emissions and aid in the responsible use of fossil fuels. In 2013, Petra Nova Holdings (a joint venture between NRG Energy and JX Nippon Oil & Gas Exploration) announced a carbon capture retrofit on one of the four coal-fired units of its Parish plant. After the retrofit, the world’s largest post-combustion carbon capture unit will be able to capture 106 million tons of CO2 per year. Designed as a demonstration plant, it aims to capture at least 90% of the CO2 from the feed stream, which equals about 40% of this unit’s capacity or 12% of the plant’s total capacity. Furthermore, it will also reduce the emission of pollutants such as sulfur oxides (SOx) and nitrogen oxides (NOx). The project, which stands under the Department of Energy of the United States’ Clean Coal Power Initiative, is expected to go into operation at the end of 2016.
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The carbon capture and storage demonstration unit at the Parish coal plant in Thompsons, TX, USA, is currently under construction. It is expected to go into service this year.
Absorbing CO2 more energy efficiently and cost effectively
In a fossil fuel power plant such as the Parish plant, CO2 emerges during the process of burning fossil fuels. Before it is released into the atmosphere, the CO2 is captured in an absorption column. The internals for such columns, such as the structured packings MellapakTM and MellapakPlusTM , are produced by Sulzer. These enable the efficient capture of CO2 from the flue gas stream before it is released into the atmosphere. The captured CO2 can then be safely stored underground or used for other purposes (e.g., enhanced oil recovery).
Normally, these columns are very large and use a lot of energy. Sulzer’s structured packing reduces the column size, thus saving material, space, and cost. CCS process providers focus on decreasing energy costs wherever possible. With Sulzer’s products, the pressure drop across the absorber can be reduced. As a result, less energy is needed for the operation of the plant. Customers benefit from lower capital and operational expenses.
In the Petra Nova project, Sulzer engineers are confronted with additional and unique challenges: the shape, material, and dimension of the towers. Two of the towers are rectangular and constructed out of cement. While these features are reasonable from a manufacturing and design perspective, the Sulzer team had to review many of the mechanical strength calculations made for cylindrical columns. The very large size of the columns added to the challenge. However, the engineers were able to optimize the equipment in close collaboration with a project partner.
Offering solutions for various stages of the CCS chain
Sulzer has gained significant experience in providing mass transfer technology for CCS. The company has delivered column internals and engineering expertise for two of the largest CO2 capture demonstration projects worldwide, among them the SaskPower Boundary Dam CCS project in Canada. With its technology, customers are able to treat large amounts of flue gas most effectively. This is even more important when considering that, in many cases, not only CO2 needs to be separated from the gas stream, but NOx and SOx emissions as well. In addition to mass transfer technology, Sulzer also offers pumps for various stages of the CCS chain. For example, these pumps can be used to circulate liquids in the capture process. Other application areas are the compression, transport (e.g., via pipelines), and injection of the captured CO2.
In the case of the WA Parish power plant, the captured CO2 will be used for enhanced oil recovery in the Gulf Coast region. Those responsible expect this will boost oil production from about 500 barrels per day to approximately 15 000 barrels per day. Thus, besides enhancing the long-term viability and sustainability of power plants, it also profitably increases oil production.
Although CCS technology is still at an early stage, pilot projects around the world have demonstrated the effectiveness of the technology. Sulzer is liaising with customers and is involved at an early stage in the process design phase of such projects. The company is committed to seizing the opportunities emerging in this field.