THE MOLECULAR GATE~R CO_2 REMOVAL PROCESS OPERATING EXPERIENCE AT TIDELANDS OIL PRODUCTION FACILITY AND APPLICATIONS OF THE TECHNOLOGY

摘要

The first Molecular Gate~R-Nitrogen Rejection~R system has operated for over two years and removes 18% nitrogen from glycol dehydrated wellhead gas while producing pipeline specification product at an unattended site in Southwest Colorado. The patented system is operated by the pumper for the wells and is checked on a daily basis during his routine visits to the site. With no other attention, the system has been available 99% of the time and has maintained consistent performance since start-up (1). In May of 2002, the first Molecular Gate-Carbon Dioxide Removal system for the removal of carbon dioxide was started-up at the Tidelands Oil Production Company operated facility in Long Beach, California. The feed source for the unit is hydrocarbon rich, water-saturated, associated gas from water flood enhanced oil recovery operations. The feed CO_2 concentration varies widely and though originally designed for 18% carbon dioxide, it more typically operates at 30% while reducing the carbpm dioxide level to less than 2%. Due to the source of the feed, a large quantity of heavy hydrocarbons is also present and the feed is water saturated. The unit removes carbon dioxide, heavy hydrocarbons and water producing pipeline specification gas for sale to the local natural gas utility company. The system offers a new route for the removal of bulk levels of carbon dioxide using proprietary adsorbent that has a high affinity for carbon dioxide while having a low capacity for methane. This adsorbent is utilized in a pressure-swing adsorption (PSA) system, typically consisting of three to four adsorber towers in which one vessel is removing carbon dioxide and water at any point in time while the natural gas product passes through the bed at high pressure unaffected by the process. Depressurizing the system to low pressure and removing the carbon dioxide from the unit regenerates the adsorbent. The system has advantages over the traditional amine and membrane processes for certain applications. It is ideally suited for coal bed methane and is appropriate for a wide range of natural gas conditions. This paper presents the technology of the Molecular Gate process along with the operating experience for the Tidelands unit, targeted applications and economic guidelines for the technology.