Asmira Delic, Xiaoyun Li, Stian Trædal, Knut Maråk, Thor Mejdell, Kai Hjarbo, David Berstad, Hans Georg Jacob Stang
{"title":"Experimental Investigation of Solid Formation under CO2 Liquefaction Conditions for Ship Transport at 7 and 16 Bar with Water Content up to 300 ppm","authors":"Asmira Delic, Xiaoyun Li, Stian Trædal, Knut Maråk, Thor Mejdell, Kai Hjarbo, David Berstad, Hans Georg Jacob Stang","doi":"10.1021/acs.iecr.4c03556","DOIUrl":null,"url":null,"abstract":"Ship-based transport of CO<sub>2</sub> is crucial in developing a carbon capture and storage (CCS) infrastructure. Lowering the ship transport pressure of liquid CO<sub>2</sub> from the conventional 14–18 to 7 bar increases the vessel-based transport capacity, leading to significant cost reductions. However, this reduction in pressure necessitates stringent water dew point control measures to prevent the formation of ice and CO<sub>2</sub> hydrates, which could block pipelines and equipment. The capital and energy demands of complete dehydration of CO<sub>2</sub> increase the CAPEX and the OPEX of the system. It is therefore important to know the limits for water content in the CO<sub>2</sub> stream and the consequences if this system cannot reach the dehydration specification due to operational upsets. This study experimentally investigated possible solid formation under CO<sub>2</sub> liquefaction for ship transport conditions at 16 and 7 bar, containing varying water concentrations. Using a CO<sub>2</sub> stream from a postcombustion amine-based capture plant to represent a realistic CO<sub>2</sub> composition, five tests were conducted at different liquefaction pressures and water contents. The experimental results were compared to the hydrate equilibrium predictions for pure CO<sub>2</sub>. It was found that, for low-pressure CO<sub>2</sub> liquefaction with 200 ppm water, signs of solid formation started to occur at about 6.7 bar, which led to complete blocking of the filter over the course of approximately 1 h as the pressure was further reduced to 6.5 bar. This is clearly above the triple point pressure, so the solids that formed were most likely hydrates. For low-pressure CO<sub>2</sub> liquefaction with 100 ppm of water operating very close to the triple point and the hydrate formation area, there was no increase in the pressure drop across the filter. For medium-pressure CO<sub>2</sub> liquefaction at 16 bar, no indication of solid formation was observed with a water content of 200 and 300 ppm. These findings show the effects of exceeding the current water specification during liquefaction of low- and medium-pressure CO<sub>2</sub> for ship transport.","PeriodicalId":39,"journal":{"name":"Industrial & Engineering Chemistry Research","volume":"10 1","pages":""},"PeriodicalIF":3.8000,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Industrial & Engineering Chemistry Research","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1021/acs.iecr.4c03556","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Ship-based transport of CO2 is crucial in developing a carbon capture and storage (CCS) infrastructure. Lowering the ship transport pressure of liquid CO2 from the conventional 14–18 to 7 bar increases the vessel-based transport capacity, leading to significant cost reductions. However, this reduction in pressure necessitates stringent water dew point control measures to prevent the formation of ice and CO2 hydrates, which could block pipelines and equipment. The capital and energy demands of complete dehydration of CO2 increase the CAPEX and the OPEX of the system. It is therefore important to know the limits for water content in the CO2 stream and the consequences if this system cannot reach the dehydration specification due to operational upsets. This study experimentally investigated possible solid formation under CO2 liquefaction for ship transport conditions at 16 and 7 bar, containing varying water concentrations. Using a CO2 stream from a postcombustion amine-based capture plant to represent a realistic CO2 composition, five tests were conducted at different liquefaction pressures and water contents. The experimental results were compared to the hydrate equilibrium predictions for pure CO2. It was found that, for low-pressure CO2 liquefaction with 200 ppm water, signs of solid formation started to occur at about 6.7 bar, which led to complete blocking of the filter over the course of approximately 1 h as the pressure was further reduced to 6.5 bar. This is clearly above the triple point pressure, so the solids that formed were most likely hydrates. For low-pressure CO2 liquefaction with 100 ppm of water operating very close to the triple point and the hydrate formation area, there was no increase in the pressure drop across the filter. For medium-pressure CO2 liquefaction at 16 bar, no indication of solid formation was observed with a water content of 200 and 300 ppm. These findings show the effects of exceeding the current water specification during liquefaction of low- and medium-pressure CO2 for ship transport.
期刊介绍:
ndustrial & Engineering Chemistry, with variations in title and format, has been published since 1909 by the American Chemical Society. Industrial & Engineering Chemistry Research is a weekly publication that reports industrial and academic research in the broad fields of applied chemistry and chemical engineering with special focus on fundamentals, processes, and products.