Considerations for Making Steel Plants CCS-Ready in China

Lihua Ren, zhigang Jia, Muxin LIU, Xi Liang, Qianguo Lin, Hasan Muslemani, Mengfei Jiang, Jon Gibbins

Research output: Working paper

Abstract

The steel sector is one of the largest industrial sources of CO2 emissions, contributing around 28% of the global industry sector’s direct greenhouse gas emissions. Since 2012, China has accounted for approximately half of global steel production, rendering it critical to explore ways to decarbonise the Chinese steel sector. One important technological option for doing so is carbon capture and storage (CCS).
‘CCS readiness’ or ‘CO2 Capture Readiness’ (CCSR) is a design concept requiring minimal up-front investment in the present to maintain the potential for CCS retrofit in the future. As such, capture readiness avoids a carbon lock-in effect in the steel industry. This report outlines the key technical and design requirements to ensure that a steel plant is capture-ready.
A hypothetical case study is also undertaken to develop a conceptual CCR design for a project capturing 0.5 million tonnes of CO2 from the off-gas of a steel plant hot stove at a capture efficiency of 90%, using a generic amine solvent (30 wt% MEA) as a base-case scenario.
The study focuses on the key elements required to make steel plants CCS-ready in China. These are:
• The geographic location of the plants, which plays a major role in determining its suitability for CO2 capture as this, after the addition of the capture plant, enables captured CO2 to be transported for geological storage and/or enhanced oil recovery (EOR);
• The technical feasibility of retrofitting the chosen carbon capture technology;
• The availability of sufficient space on or near the site to accommodate carbon capture equipment in the future; and
• Pre-investment considerations to ease the capture retrofit and reduce plant down-time in the future retrofit.
A preliminary GIS analysis indicated that 51 out of 142 steel plants in China are within a 200km radius from a CO2 storage site, which opens up scope for further research on CO2 storage opportunities for steel plants (see Figure 1). A review of the essential requirements of various carbon capture technology options for nine types of flue gas streams was undertaken to provide the basis for further selection. An update to this review would be beneficial to track the progress of emerging capture technologies. Equally important is ensuring that plants can accommodate any new technologies that may not be as competitive currently, so that they may be rapidly deployed when they become available.
A case study for a hypothetical CCSR project for capturing 0.5 million tonnes of CO2 has been performed to develop a conceptual design for meeting the requirements of a carbon capture-ready steel plant. The study assumed the use of a generic amine solvent (30 wt% MEA) – the most mature CO2 capture technology to date. The study assumes the capture of 70 tonnes of CO2 per hour from off-gas with a representative concentration value of 25% CO2 at expected capture efficiency of 90%. ASPEN Plus process simulation software was used to develop a CCSR concept design.
The study results are summarised below:
• A high-level capture plant design was developed in this case study, including an indicative amine-based absorption process flow diagram showing major streams and the main equipment, Heat and Mass Balance, preliminary equipment size, utilities consumption and other key engineering performance parameters;
• The space required for the capture unit at a 0.5 million tonnes level is estimated at around 4,000m2, which includes the pre-treatment unit, amine unit, operation control building, as well as a CO2 compression unit for CO2 transportation and storage. The additional space required for utilities supply facilities is estimated at around 1,200m2;
• The comprehensive utilisation of waste heat would be advantageous for CCS applications in China’s steel production. It is recommended that back-pressure steam turbines are used to drive multi-stage CO2 compression instead of electric-motor-driven compressors with huge power loads of 7,100kW. The steam recovered from waste heat boilers is fed to the steam turbine, exhaust steam at low pressure from the back-pressure turbine is then fed back to the reboilers of the carbon capture unit to provide approximately 75% of the amine regeneration heat requirements (without a MVR process heat recovery option); and
• Potential pre-investment options are identified to ease future capture retrofit.
Generally, this study provides an analytical approach and engineering principles to support CCSR plant design. It may be adopted to develop a more rigorous conceptual CCS-readiness design of steel plants at the FEED stage.
Original languageEnglish
Publication statusPublished - 2019

Keywords

  • CCS ready
  • capture ready
  • steel
  • CCS
  • China
  • Amine
  • post combustion capture

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