|An earlier version of the ASMR in the lab. Source: Modine Manufacturing.|
Modine Manufacturing Company and Chevron Technology Ventures are expanding their collaboration and entering a second phase in the development of on-site hydrogen generation technology for hydrogen fueling stations.
In collaboration with Chevron and BASF Catalysts LLC, Modine developed a highly integrated Advanced Steam Methane Reformer (ASMR). The ASMR will be a component of a purified hydrogen unit (PHG) that will be used in a hydrogen refueling station in Michigan, designed and built by Chevron Hydrogen Company.
We combined our thermal management and manufacturing expertise with BASF’s catalyst development and application knowledge, along with Chevron’s process development experience in the field of steam methane reforming. This led to a highly efficient and cost competitive product.
Our prototype reformer remains on test, logging more than 1,000 hours since April 2005, with excellent results while maintaining steady performance.—Mark Baffa, Modine’s Director of Fuel Cell Products Group
|Design of the ASMR prototype. Click to enlarge.|
Modine and Chevron Technology Ventures announced the ASMR reformer technology in April, 2005 and are testing it at a Chevron lab in Houston, Texas. In the next phase, the PHG will be coupled with a compressor, and storage and dispensing systems at the fueling site to supply hydrogen in a quality needed for hydrogen fueled vehicles.
The new PHG will be installed at Chevron’s Hydrogen Energy Station on a United States military base in Selfridge, Michigan, near Detroit, and will provide hydrogen for a fleet of light-duty fuel-cell vehicles. The PHG is expected to be installed and operational starting in the summer of 2007. The Michigan location will be one of the first cold climate areas where this technology is tested.
|The fin geometry. Click to enlarge.|
The new compact reformer design features mechanical as well as thermal integration of the steam reforming, catalytic oxidizer, and water-gas shift reactions in a single vessel. Concentric fin-type heat exchangers coated with catalysts allow the heat generated by the endothermic oxidizing reaction to be directly transferred to the endothermic steam reforming reaction. The design is thermally neutral and requires no external cooling and no control loops, and improves the energy balance of an SMR system.
The ASMR reactor incorporates patent-pending technology from Modine and Chevron, which includes catalyst-coated heat exchangers. These heat exchangers provide high efficiency through their compact and integrated reactor technology.—Mark Voss, Modine Fuel Cell Products Group Engineering Manager
The process chemistry for small-scale SMR is the same as in a large scale refinery, but with severe economy-of-scale penalties. In the paper presented at the National Hydrogen Association conference in 2005, the Chevron Ventures (then ChevronTexaco) and Modine authors noted:
Traditional SMR employs a combination of direct and indirect heat transfer, where heat is generated oxidizing auxiliary fuel to provide the necessary thermal energy for the steam reforming reaction... product gases (reformate) generated by the steam reforming reaction are then typically cooled, using a heat exchanger, to a desired temperature range necessary for the subsequent water-gas shift (WGS) reaction to occur.
Although the process chemistry remains the same for a small scale SMR (50 – 100 kg/day H2) when compared to a large scale refinery SMR, there are severe economy of scale penalties related to capital costs for small-scale SMR-based hydrogen energy stations.
In addition, natural gas reforming is a relatively high temperature process. Scaling the process down from larger systems results in greater heat losses that contribute directly to lower production efficiency, higher operating costs, and ultimately higher cost of hydrogen.
To address these challenges, the project approach aims at developing a small-scale SMR that is: (1) thermally and mechanically integrated to maximize heat recovery, minimize heat loss, and minimize balance of plant components, (2) able operate at pressure required for purification step to minimize electrical power consumption, and (3) thermally balance to achieve passive temperature control and to minimize the number of process control loops.
Each reactor vessel is designed to produce 40 kg of hydrogen per day. The reformer’s maximum reformer hydrogen production rate is 55 kg/day, based on 145 kg/day of natural gas input.
“Chicken… Meet the Egg! A Cost Effective Hydrogen Supply Solution”; K. Nguyen, C. Krause, B. Balasubramanian, K. Spilker, M. Reinke, J. Valensa (ChevronTexaco Technology Ventures and Modine Manufacturing Company, Fuel Cell Products Group)