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Innovative gas processing

IP.com Disclosure Number: IPCOM000182659D
Publication Date: 2009-May-05
Document File: 6 page(s) / 113K

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Page 1 of 6

Innovative Gas Processing with Various LNG Sources

Joseph Cho, Felix de la Vega, Heinz Kotzot, and Charles Durr

Kellogg Brown & Root (KBR), USA

(article written for LNG Journal

to be published in the Jan/Feb 2005 issue)

Page 2 of 6

Innovative Gas Processing with Various LNG Sources

Joseph Cho, Felix de la Vega, Heinz Kotzot, and Charles Durr

Kellogg Brown & Root (KBR), USA

Introduction

The combination of increased demand in the power generation sector that uses Natural Gas (NG) as fuel to their gas turbines and the unexpected decline in domestic gas production has caused NG prices to get into an upward spiral in the United States (U.S.). Natural Gas imported through the Canadian border would help bridge the gap between the current increased demand and the U.S. production rate, but not for long since Canadian gas production is expected to decrease by 2007. Pipeline gas imports alone, however, would not push back escalating NG prices. This situation has revitalized LNG import into the U.S. even though it has been inactive for more than two decades. With a few exceptions, most LNG producers favor the LNG specifications of the Asian Pacific market where about 70% of LNG has been consumed [1]. The Asian Pacific market requires High Heating Value (HHV) LNG. Nitrogen dilution has been widely used to reduce pipeline gas High Heating Values (HHV). However, this process has a considerable restriction in adjusting the HHV of regasified LNG and component requirements because it cannot enrich the methane content in the feed LNG and the allowable nitrogen injection is limited by the pipeline gas specification. There are many prospective importers willing to supply LNG to the US market. A point of negotiation will be their range of LNG compositions. In the event of limited sources of LNG to meet market requirements, a viable option will be to install LNG processing facilities at the reception terminal to meet the required HHV as well as component limits required to meet pipeline specifications. The California Air Resources Board (CARB) has unique pipeline gas specifications that require stringent HHV and heavy hydrocarbon contents. The range of concentration and components in the specification are as follows:
• C1: Min. 88 mol%
• C2: Max. 6 mol%
• C3+: Max. 3 mol%
• Inerts (N2, CO2): 1 - 4.5 mol%

Rich LNG has low methane and high heavier hydrocarbons (C2+), which will require methane enrichment, i.e. heavy hydrocarbons removal to meet the CARB spec. Without LNG processing by a fractionation facility, very few LNG sources could be imported to the U.S. West Coast. Thus, fractionation will provide flexibility in purchasing, scheduling, and other negotiating initiatives, resulting in lower LNG importation costs. This article proposes a new LNG fractionation process that involves one step pressurization of LNG by using high-head intank pumps in order to feed LNG directly into the fractionation facility...