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PROPOSAL:

Execute Contract to Co-sponsor Development and Demonstration of Advanced Safety Inspection Methods for NGV Tanks

SYNOPSIS:

During normal operations of NGVs, the compressed natural gas tanks can endure adverse conditions, which over time, could potentially compromise the safety of these tanks. Current methods of visual inspection are inadequate to reliably detect damage to the tanks. The Gas Research Institute, in conjunction with Battelle Memorial Institute, has proposed to develop and demonstrate an advanced damage indicator coating system and an advanced ultrasonic acoustic detection system to significantly improve the accuracy and ease with which structural damage to an NGV tank can be detected. Total cost of this project is $2.303 million. AQMD cost-share will not exceed $325,000.

COMMITTEE:

Technology, October 22, 1999, Recommended for Approval

RECOMMENDED ACTION:

Authorize the Chairman to execute a contract with the Gas Research Institute to cosponsor the development and demonstration of an advanced damage indicator system and an advanced ultrasonic acoustic testing method to assist the safety inspection of NGV storage tanks in an amount not to exceed $325,000 from the Clean Fuels Fund.

Barry R. Wallerstein, D.Env.
Executive Officer

Background

The AQMP identifies the use of alternative clean fuels in mobile sources as a key attainment strategy. Alternative fuel vehicles, such as NGVs, have demonstrated significantly lower VOC, NOx, CO and toxic emissions than gasoline vehicles. Given these attractive emission characteristics of NGVs, several incentive programs are in place to encourage public and private fleet operators to switch to NGVs. As NGVs grow in commercial importance, the safety aspects of handling pressurized natural gas stored onboard become increasingly important given the mix of skill level of the operators that handle these tanks in the field.

Even though NGV cylinders are safe and reliable in the field, these tanks are exposed to a range of environmental conditions that, over time, can reduce the integrity of a storage cylinder. Specifically, in the United States, since 1993, there have been seven safety incidents involving NGV storage cylinders. All of these ruptures have been the result of damage to the composite over-wrap of the cylinder, damage severe enough to compromise the mechanical strength of the cylinder until rupture occurred. Industry experts are concerned that if these safety incidents continue, the commercialization of NGVs could be significantly slowed down.

Current visual inspection methods of storage cylinders are effective, but limited. These limitations include difficulty in detecting damage to certain colors of composite material, expensive downtime for the inspection, and the need for well-trained, skilled maintenance staff to conduct these inspections. Other currently available inspection techniques, such as hydrostatic testing, have the additional limitation of potential damage to the cylinder caused by removal of the cylinder from the vehicle during the inspection process. As a result, there is a need to develop smart cylinder technology that will provide safety warnings to operators with regard to the immediate condition of NGV tanks. Such safety warnings coupled with prompt corrective action, could reduce the risk of a tank failure to very low levels.

Proposal

In March 1997, the Gas Research Institute (GRI) issued a competitive solicitation, Request for Proposal (RFP) #97-940-0539 entitled "Advanced Composite – NGV Cylinder Enhancement Program" with funding availability of up to $1,000,000. The proposal sought to develop smart cylinder technology including applying damage indicator coating technology to all-composite cylinders. In addition, the proposal called for development of acoustic ultrasonic (AU) technology, which represents a more advanced form of detecting impending failure in storage tanks. Battelle Memorial Institute was selected by GRI for funding as a result of this competitive RFP.

With regard to the damage indicator coating, the focus will be on Type 3 cylinders, or those cylinders comprised of a metal liner and a full composite overwrap. The project team will work with Type 3 cylinder manufacturers to identify and refine the damage indicator coating to achieve suitable coating activation levels. The selected coating will be applied and tested on several Type 3 cylinders to demonstrate the validity of the technology. The testing will include intentionally inducing damage to the cylinders followed by several refueling cycles and cylinder burst tests. Following laboratory tests, cylinders with the damage indicator coating will be installed in several vehicles for field evaluation. The test fleets are expected to include a local transit agency and another centrally fueled fleet, perhaps a delivery fleet or utility. The field demonstration is expected to last one year.

The acoustic ultrasonic technology will focus on Type 4 cylinders, or cylinders with a plastic liner and a full composite overwrap, specifically those manufactured by project team member Lincoln Composites. Type 4 cylinders will be put through several cycles of intentionally induced damage, followed by acoustic ultrasonic testing of the cylinders, followed by burst and/or cycle test of the cylinders to demonstrate ultimate validity of the detection technology. Field tests of this acoustic ultrasonic testing system, using the same local fleets described before, are planned as part of the proposed project.

Benefits to AQMD

The proposed project is included in the November 1998 update of the Technology Advancement Plan under Project 98M1-6, "Development of Advanced Technologies for On-Board Gaseous Fuel Storage." The proposed project addresses the air quality objectives stated in the AQMD’s AQMP which heavily rely on the expedited implementation of low-emission, clean fueled vehicles to achieve air quality standards in Southern California.

The proposed project addresses one of the major concerns facing NGV commercialization, namely the safety of NGV onboard tanks. The burst strength of NGV fuel tanks, however, can be reduced by repeated mechanical impacts, excess temperatures and by chemical exposures. Smart cylinder designs that include the proposed "damage" indicator coatings and ultrasonic acoustic technology can monitor the instant structural condition of the tanks. Such smart designs potentially can reduce the frequency and cost of tank inspections while reducing the likelihood of tank failures in the field.

Thus, the project has the potential to significantly advance the safety of NGV storage tank technology, and will allow operators with a range of skill levels to safely handle NGV tanks in the field. This could accelerate the acceptance of NGVs in the marketplace, which in turn, would help expedite air quality gains in the Basin.

Sole Source Justification

Section VIII.B.2 of the Procurement Policy and Procedure identifies four major provisions under which a sole source award may be justified. This request for a sole source award is made under provisions B.2.c(1), "the desired services area are available from only the sole source based upon the unique experience and capabilities of the proposed contractor or contractor team," and B.2. d(1), "other circumstances, including projects involving cost sharing by multiple sponsors." It is in the best interest of the AQMD to cosponsor this innovative project proposed by GRI and its contracting team that consists of Battelle and Lincoln Composites.

GRI has unique experience and capabilities in advancing NGV technology. GRI is the primary research, development and commercialization funding organization for the natural gas industry. GRI has an extensive program in advancing the NGV fuel storage tank technology including projects with some of the leading vendors of NGV tanks. GRI issued a competitive solicitation in March 1997, RFP #9798-940-0539, entitled "Advanced Composite – NGV Cylinder Enhancement Program." As detailed below, substantial cost-sharing is brought to the project by GRI and its project team.

Battelle Memorial Institute has also unique capabilities in this field. Battelle is among the country’s leading national laboratories with extensive experience with alternative fuels. Battelle was the winner in a competitive solicitation to develop and implement the proposed technology of damage indicator and ultrasonic acoustic method. Battelle has already developed a damage indicator coating and demonstrated its proof-of-concept in the laboratory. This includes developing a coating technology containing extremely tiny beads that rupture and change color when impacted beyond a threshold level, developing a bonding system to apply this coating to a NGV tank on a production line, and proof testing the validity of the coating.

Lincoln Composites is among the leading manufacturers of NGV storage tanks. They primarily supply all-composite tanks, and will supply the NGV tanks for testing both the damage indicator and the acoustic technology.

Resource Impacts

AQMD cost-share will not exceed $325,000 of this $2.303 million project with the expected cost-sharing listed below.

 

Cosponsor	Cash	In-kind
GRI	$987,000	-
DOE/Oak Ridge National Lab	900,000	-
Lincoln Composites		$91,000
AQMD	325,000	-
Totals	$2,212,000	$91,000

Sufficient funds are available from the Clean Fuels Fund, established as a special revenue fund resulting from the state-mandated Clean Fuels Program. The Clean Fuels Program, under Health and Safety Code 40448.5 and 40512 and Vehicle Code 9250.11, establishes mechanisms to collect revenues from mobile sources to support projects to increase the utilization of clean fuels, including the development of the necessary advanced enabling technologies. Funds collected from motor vehicles are restricted, by statute, to be used for projects and program activities related to mobile sources that support the objectives of the Clean Fuels Program. This project is a proper use of these funds because the proposed technology, if successful, will facilitate the increased use of clean burning natural gas vehicles in the Basin.

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