Vol 1 Chapter 30: Revamping Heaters and Boilers to Oxyfiring-producing Oxygen by ITM Technology
Rodney Allam, Vince White, VanEric Stein, Colin McDonald, Neil Ivens and Mark Simmonds
Abstract: The work reported in Chapter 30 considered the issues involved in modifying the process heaters and boilers for oxyfuel combustion and locating two world scale air separation plants totalling up to 7400 tonnes/day of oxygen plus a CO2 compression and purification system on a congested site. In addition we presented the scheme for distributing the oxygen around the site and collecting the CO2-rich effluent from the combustion processes for purification, final compression, and delivery into a pipeline for enhanced oil recovery (EOR). In this Chapter, we will look at an alternative oxygen generation technology that would replace the two cryogenic air separation units (ASUs). This technology utilises ion transport membranes (ITMs) to produce the oxygen. The ITM oxygen process is based on ceramic membranes that selectively transport oxygen ions when operated at high temperatures. Under the influence of an oxygen partial pressure driving force, the ITM achieves a high flux, high purity (99þ mol%) separation of oxygen from a compressed-air stream. By integrating the non-permeate stream with a gas turbine system, the overall process co-produces high purity oxygen, power, and steam if desired. The base case, Case 1, is presented and costed and involves the supply of the complete oxyfuel system with installation and startup and includes all required utilities. In order to provide the hot air for the ITM oxygen process, two Siemens V94.2 combined cycle gas turbines are used and excess power is exported to the local electricity grid. Two further cases are also presented. Case 2 also uses two Siemens V94.2 gas turbines plus a heat recovery steam generator (HRSG) producing steam primarily at the refinery condition of 127 barg 518 8C together with some additional supplies at 13.7 barg and some boiler feed water. The steam production from the existing boilers is reduced by a corresponding amount. The turndown of the steam boilers results in a reduction in the oxygen requirement from 6626 to 3828 tonnes/day. Case 3 uses one Siemens V94.3 gas turbine plus a HRSG, but in this case the fuel is hydrogen produced from an oxygen autothermal reformer (ATR) with product steam generation and CO2 removed using an methyl diethanolamine (MDEA) system. The gas turbine waste heat boiler produces steam at the refinery conditions as in Case 2. In this case, the use of hydrogen fuel gas allows operation of the gas turbine combustor at a much lower oxygen inlet concentration compared to Cases 1 and 2 which use natural gas fuel. This feature allows for greater oxygen recovery, which allows the entire oxygen requirement to be met with a single gas turbine, thereby minimising export power and decreasing capital cost. In each of these three cases the total quantity of CO2 emission avoided and the quantity of CO2 available for pipeline delivery is calculated, costed and presented in Table 1.
Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO2 Capture Project Capture and Separation of Carbon Dioxide from Combustion Sources - Volume 1
Edited by: David C. Thomas, Senior Technical Advisor, Advanced Resources International Inc, USA
(571 Kb) Download