Advanced Palladium Membrane Scale-up for Hydrogen Separation Metadata

Title

• Main Title Advanced Palladium Membrane Scale-up for Hydrogen Separation

Creator

• Author: Emerson, Sean
  Creator Type: Personal
• Author: Magdefrau, Neal
  Creator Type: Personal
• Author: She, Ying
  Creator Type: Personal
• Author: Thibaud-Erkey, Catherine
  Creator Type: Personal

Contributor

• Sponsor: United States. Department of Energy.
  Contributor Type: Organization

Publisher

• Name: United Technologies Corporation
  Place of Publication: United States

Date

• Creation: 2012-10-31

Language

• English

Description

• Content Description: The main objective of this project was to construct, test, and demonstrate a Pd-Cu metallic tubular membrane micro-channel separator capable of producing 2 lb day{sup -1} H{sub 2} at ≥95% recovery when operating downstream of an actual coal gasifier. A key milestone for the project was to complete a pilot-scale gasifier test by 1 September 2011 and demonstrate the separation of 2 lb day{sup -1} H{sub 2} to verify progress toward the DOE’s goals prior to down-selection for larger-scale (≈100 lb day{sup -1}) hydrogen separator development. Three different pilot-scale (≈1.5 ft{sup 2}) separators were evaluated downstream of coal gasifiers during four different tests and the key project milestone was achieved in August 2011, ahead of schedule. During three of those tests, all of the separators demonstrated or exceeded the targeted separation rate of 2 lb day{sup -1} H{sub 2}. The separator design was proved to be leak tight and durable in the presence of gasifier exhaust contaminants at temperatures and pressures up to 500 °C and 500 psia. The contaminants in the coal gasifier syngas for the most part had negligible impact on separator performance, with H{sub 2} partial pressure being the greatest determinant of membrane performance. Carbon monoxide and low levels of H{sub 2}S (<39 ppmv) had no effect on H{sub 2} permeability, in agreement with laboratory experiments. However, higher levels of H{sub 2}S (>100 ppmv) were shown to significantly reduce H{sub 2} separation performance. The presence of trace metals, including mercury and arsenic, appeared to have no effect based on the experimental data. Subscale Pd-Cu coupon tests further quantified the impact of H{sub 2}S on irreversible sulfide formation in the UTRC separators. Conditions that have a thermodynamic driving force to form coke were found to reduce the performance of the separators, presumably by blockage of effective separation area with carbon deposits. However, it was demonstrated that both in situ and ex situ (laboratory) air regeneration at 450 °C could restore separator performance by burning out such deposits. Gasifier testing revealed that high molecular weight hydrocarbons have the potential to retard H2 separation. Unconverted coal tars with carbon numbers greater than 14 have a boiling point such that they can act as a reversible poison to the Pd-Cu membranes even at temperatures above 500 °C. The use of real-time, physics-based, performance models revealed the effect of these coal tars. It is believed that this project provided the first evidence for the impact of coal tars on H{sub 2} separator performance. Final down-selection of candidate alloys for non-membrane materials of construction proceeded by evaluating the alloys in both UTRC laboratory tests and testing downstream of an actual gasifier at the National Carbon Capture Center (NCCC). The overall alloy ratings were calculated by multiplying the projected cost of a 100 lb day{sup -1} H{sub 2} separator outer shell by the projected oxide scale thickness for 5 years of operation. The alloy with the lowest resulting rating parameter was stainless steel 309 (SS-309) followed by stainless steel 310 (SS-310). However, it was noted that approximately half of the alloys showed susceptibility to pitting and localized corrosion. SS-309 was one of the alloys that exhibited heavy localized attack after 2000 hours of laboratory testing. As this localized corrosion can potentially lead to accelerated end of life, it was determined that SS-310 would be the best alloy selection for this application as it does not show signs of localized pitting corrosion.

Subject

• STI Subject Categories: 08 Hydrogen

Collection

• Name: Office of Scientific & Technical Information Technical Reports
  Code: OSTI

Institution

• Name: UNT Libraries Government Documents Department
  Code: UNTGD

Resource Type

• Report

Format

• Text

Identifier

• Grant Number: FE0004967
• DOI: 10.2172/1063878
• Office of Scientific & Technical Information Report Number: 1063878
• Archival Resource Key: ark:/67531/metadc838687