Norcem's cement plant in Brevik is a mammoth in the landscape between the road and the sea. The test plants for CO2 capture seem minuscule compared with the giant incinerator and the surrounding concrete structures. Only Aker Solutions' 40-metre-high adsorption tower stands out. However, the significance of the technologies being tested will be far from minuscule if they are successful.
"Progression in the project is very good.
We are on track, and have the finances in check. We can already see at this stage that we will be able to capture CO2 from the cement production," says Liv Bjerge in HeidelbergCement Norcem.
Bjerge heads the extensive project where four technologies are being tested to see which is best suited for capturing CO2 in the flue gas in cement plants. Norcem is the project manager with HeidelbergCement and European Cement Research Academy (ECRA) as industry partners. The project is supported by CLIMIT Demo.
Two of the technologies have progressed quite far in terms of development. Aker Solutions and Alstom are therefore completing their test programmes this autumn. The two immature technologies - solid absorbent (RTI) and membranes (Norwegian University of Science and Technology, Yodfat Engineers, DNV GL) - must undergo two test phases. RTI has finished test phase I and is planning test phase II, while the membrane consortium will complete test phase I later this autumn.
Three of the four test plants are located in Brevik
where they are supplied with flue gas directly from the cement production. The flue gas, which contains 17-20 per cent CO2, as well as SO2, NOx, dust and water vapour, is a very corrosive mixture when the water condenses. It was challenging for Norcem to design the process so that the test plants would be supplied with flue gas at the correct rate and temperature. They also had to choose suitable materials which could handle the flue gas. Both issues were solved earlier this year.
Status of the four technologies in September 2014
Aker Solutions is the most experienced player in Norcem's test project. Aker's mobile test unit (MTU) is container-based and has previously been used for extensive testing at the CO2 Technology Centre Mongstad and coal power plants in the UK and US. Assembly in Brevik and connection to the flue gas pipe from the cement plant was virtually a matter of 'plug and play'.
Aker is testing its new proprietary amine during the six-months test period at Norcem. The amine mixture was optimised in SINTEF's CO2 laboratory at Tiller in Trondheim. Results so far are promising, including a documented reduction in energy consumption.
The MTU runs 24/7 and has so far logged 1300 hours of operation in Brevik. The capture plant cleans 450 normal cubic metres of flue gas per hour with 90 percent CO2 capture. Several test campaigns have shown that the content of degradation products from amine in the air over the plant is quite low. The test run has also shown that consumption of amine is low.
Aker will continue its tests through the end of October and will deliver the result report for test phase I in November.
The Research Triangle Institute from the US has developed a solid sorbent. The institute has several CO2 capture projects for coal power in the US, but this is the first time they have tested their technology in a cement plant. The plant is remotely controlled from the US, but operated by Norcem.
The CO2 capture takes place in cycles. First, the solid sorbent captures CO2 until it is fully saturated. The absorbent is then heated so that clean CO2 is released. The critical factor is how well the absorbent collects CO2.
Testing since April has shown that the technology works well with a high rate of CO2 capture from the flue gas. In August, RTI was approved by the project board to move on to phase 2. This will involve testing an even more efficient sorbent and installing a much larger plant at Norcem. The pilot will stand three levels tall and testing will be going on until the spring of 2016.
NTNU/DNV GL/Yodfat Engineers - membranes
Professor May-Britt Hägg at NTNU, who is behind the development of membranes which separate CO2 from the flue gas, is cooperating with DNV GL and Yodfat Engineers in the test programme. NTNU made the membranes, Yodfat Engineers made the module which the membranes are located in and installed the equipment in Brevik, while DNV GL is the coordinator and is responsible for modelling the full-scale test plant.
The membranes are sensitive to the aggressive flue gas, and the project group therefore constructed a pre-treatment plant which cleans the flue gas of SO2 and NOx and removes particles. The membrane unit is able to capture 70 percent of the CO2 in the flue gas.
Alstom developed a technology which uses the raw material from cement production to capture CO2. As part of Norcem's project, a feasibility study is being carried out to test the technology at IFK University in Stuttgart using limestone from Verdal.
The challenge associated with this technology lies in transporting the lime between the column where CO2 is captured and the column where CO2 is released. The tests will, among other things, provide an indication of how long the limestone can be used before it must be replaced, and how much new limestone needs to be added during the process. The two completed test campaigns confirmed the calculated energy balance and material balance. Alstom's researchers are now analysing the data and will deliver their report in November.
Benchmark study compares full-scale
"We will find out which technologies are best suited for the cement industry, and energy consumption is important in this context. For example, the cement plant in Brevik has a lot of waste heat which can be used in the capture process," says Bjerge.
Need to be realistic
24 MW of waste heat can be made available at Norcem. Aker Solutions has estimated that with this heat energy, Norcem could capture about 30-40 per cent of the CO2. This corresponds to 300 000 – 400 000 tonnes of CO2 each year.
"The debate in Norway revolves around building a full-scale demonstration plant. We in the cement industry need to carry out this project to understand the feasibility of CO2 capture, particularly within the cement segment. As regards energy needs, it is quite possible that a smaller scale plant is more realistic. Let us rather capture 400 000 tonnes and gain extensive knowledge and experience that could benefit others," says Bjerge.
Where will they send the CO2?
All CO2 captured in the test plants is released. However, if Norcem is to start capturing CO2 at a large scale in the future, there must be infrastructure to receive the CO2.
"Give us a place to put the CO2. Norcem is completely dependent on the feasibility study for CCS which Gassnova started, but which was cancelled. We need a specific study in order to modify the cement plant so that we can utilise the waste heat, learn what additional space we need, choose the right technology and learn how much to compress the CO2 for further transport," says Bjerge. She praises Gassnova and CLIMIT for early support of Norcem's capture project.
Results will be presented at a conference in 2015
Norcem will organise an international conference concerning the project on 20-21 May 2015, together with ECRA. The first day of the conference will address the project and results and the second day will look towards the future with topics such as re-use of CO2 and storage possibilities.
221323 – Test plant for CO2 capture at Norcem Brevik, Project Phase II, Test Stage 1