| DOI: | 10.2172/1164581
|
| 报告号: | PNNL--23777
|
| 报告题名: | Coal-Derived Warm Syngas Purification and CO<sub>2</sub> Capture-Assisted Methane Production |
| 作者: | Dagle, Robert A.; King, David L.; Li, Xiaohong S.
|
| 出版年: | 2014
|
| 发表日期: | 2014-10-01
|
| 总页数: | 76
|
| 国家: | 美国
|
| 语种: | 英语
|
| 英文关键词: | catalysis
; CO2 capture
; syngas
; fuels
; Environmental Molecular Sciences Laboratory
|
| 中文主题词: | 碳
; 硫磺
; 冰上通道
; PH
; 水道
; 甲烷
; 污染物
|
| 主题词: | CARBON
; SULFUR
; LEADS
; PH
; METHANE
; CONTAMINANTS
|
| 英文摘要: | Gasifier-derived syngas from coal has many applications in the area of catalytic transformation to fuels and chemicals. Raw syngas must be treated to remove a number of impurities that would otherwise poison the synthesis catalysts. Inorganic impurities include alkali salts, chloride, sulfur compounds, heavy metals, ammonia, and various P, As, Sb, and Se- containing compounds. Systems comprising multiple sorbent and catalytic beds have been developed for the removal of impurities from gasified coal using a warm cleanup approach. This approach has the potential to be more economic than the currently available acid gas removal (AGR) approaches and improves upon currently available processes that do not provide the level of impurity removal that is required for catalytic synthesis application. Gasification also lends itself much more readily to the capture of CO2, important in the regulation and control of greenhouse gas emissions. CO2 capture material was developed and in this study was demonstrated to assist in methane production from the purified syngas. Simultaneous CO2 sorption enhances the CO methanation reaction through relaxation of thermodynamic constraint, thus providing economic benefit rather than simply consisting of an add-on cost for carbon capture and release. Molten and pre-molten LiNaKCO3 can promote MgO and MgO-based double salts to capture CO2 with high cycling capacity. A stable cycling CO2 capacity up to 13 mmol/g was demonstrated. This capture material was specifically developed in this study to operate in the same temperature range and therefore integrate effectively with warm gas cleanup and methane synthesis. By combining syngas methanation, water-gas-shift, and CO2 sorption in a single reactor, single pass yield to methane of 99% was demonstrated at 10 bar and 330°C when using a 20 wt% Ni/MgAl2O4 catalyst and a molten-phase promoted MgO-based sorbent. Under model feed conditions both the sorbent and catalyst exhibited favorable stability after multiple test cycles. The cleanup for warm gas cleanup of inorganics was broken down into three major steps: chloride removal, sulfur removal, and the removal for a multitude of trace metal contaminants. Na2CO3 was found to optimally remove chlorides at an operating temperature of 450ÂşC. For sulfur removal two regenerable ZnO beds are used for bulk H2S removal at 450ÂşC (<5 ppm S) and a non-regenerable ZnO bed for H2S polishing at 300ÂşC (<40 ppb S). It was also found that sulfur from COS could be adsorbed (to levels below our detection limit of 40 ppb) in the presence of water that leads to no detectable slip of H2S. Finally, a sorbent material comprising of Cu and Ni was found to be effective in removing trace metal impurities such as AsH3 and PH3 when operating at 300ÂşC. Proof-of-concept of the integrated cleanup process was demonstrated with gasifier-generated syngas produced at the Western Research Institute using Wyoming Decker Coal. When operating with a ~1 SLPM feed, multiple inorganic contaminant removal sorbents and a tar-reforming bed was able to remove the vast majority of contaminants from the raw syngas. A tar-reforming catalyst was employed due to the production of tars generated from the gasifier used in this particular study. It is envisioned that in a real application a commercial scale gasifier operating at a higher temperature would produce lesser amount of tar. Continuous operation of a poison-sensitive copper-based WGS catalyst located downstream from the cleanup steps resulted in successful demonstration. |
| URL: | http://www.osti.gov/scitech/servlets/purl/1164581
|
| Citation statistics: |
|
| 资源类型: | 研究报告
|
| 标识符: | http://119.78.100.158/handle/2HF3EXSE/41402
|
| Appears in Collections: | 过去全球变化的重建
影响、适应和脆弱性
科学计划与规划
气候变化与战略
全球变化的国际研究计划
气候减缓与适应
气候变化事实与影响
|
| File Name/ File Size |
Content Type |
Version |
Access |
License |
|
|---|
| 1164581.pdf（2616KB） | 研究报告 | -- | 开放获取 | | View
Download
|
|
|
作者单位: | Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
|
| Recommended Citation: | |
Dagle, Robert A.,King, David L.,Li, Xiaohong S.. Coal-Derived Warm Syngas Purification and CO<sub>2</sub> Capture-Assisted Methane Production. 2014-01-01.
|
|
|