NGK's Large Ceramic Membrane to Be Used in Demonstration Test for CO2 Recovery from Associated Gas during Oil Production

NGK INSULATORS, LTD. ("NGK"), based in Nagoya, Japan, announced recently that its DDR-type zeolite membrane has been adopted for use in "the demonstration test of the CO2 recovery process using DDR-type zeolite membranes." The test will be jointly conducted at an oil field in the United States by Japan Oil, Gas and Metals National Corporation (JOGMEC) and JGC Corporation (JGC). DDR-type zeolite membranes are large ceramic membranes capable of efficiently separating carbon dioxide (CO2) from natural gas mainly composed of methane (CH4) even at high pressures and high CO2 concentrations. The project represents the first-ever use of large ceramic membranes in CO2 recovery from associated gas during oil production.

NGK's DDR-type zeolite membranes have pores with a diameter smaller than 1 nanometer (one-billionth of a meter); they are capable of separating small molecules. They have a honeycomb structure with approximately 1,600 cells with an internal diameter of 2.4 millimeters that penetrate a cylindrical ceramic substrate and are 1,000 millimeters in length and 180 millimeters in diameter. The entire inner surface of the cells is formed with DDR-type zeolite membranes that selectively allow permeation of CO2. The membrane area per element is 12 square meters.

Zeolite is the name for a varied group of microporous, aluminosilicate minerals. DDR is one type; it features a structure of elliptical pores 0.36 nanometers by 0.44 nanometers in size. The pores' short diameter (0.36 nanometers) is larger than CO2 (0.33 nanometers) and smaller than CH4 (0.38 nanometers). So, when mixed gas of CO2 and CH4 is supplied to a DDR-type zeolite membrane, it allows CO2 to pass through selectively, which enables it to efficiently separate the two components.

Since 2001, NGK has manufactured and sold honeycomb-structure ceramic membranes for water purification with a pore diameter of 0.1 micrometer, diameter of 180 millimeters, and total length of 1,000-1,500 millimeters. Utilizing this manufacturing technology, NGK succeeded in creating a large-sized DDR-type zeolite membrane. The membrane area per element is larger than other tubular zeolite membranes, making it possible to reduce facility size and overall costs.

Polymer membranes are currently used for CO2 separation. They have a weakness, though: separation performance decreases at high pressures and high CO2 concentrations. The DDR-type zeolite membrane developed by NGK maintains high CO2 separation performance even at high pressure (80 atm) and high CO2 concentrations; it also possesses excellent heat resistance and can be used at high temperatures.

NGK has been partnering with JGC since 2008 to develop a CO2 removal process in natural gas fields using a DDR-type zeolite membrane, and as part of this recent joint project between JGC and JOGMEC on CO2 recovery from associated gas during oil production, it was decided that a field demonstration test would be conducted in a process that uses NGK's DDR-type zeolite membranes. The test is scheduled to be conducted for approximately one year following completion of design and construction of a test facility, which began in February 2019.