Infrastructures for fuel cell reuse and remanufacture are currently managed by individual companies. For these units not reused or remanufactured, the success of recycling depends upon the price of retrieving and processing materials from merchandise throughout an economic system and, for every type of part and material, the relation to the value of a part or material made from major (or un-recycled) supplies. Metals currently provide by far the best availability, and different gasoline cell materials (single polymers, composites, insulation, reforming media, and many others.) supply the greatest alternative for enchancment.

Starting with metals, Wernick and Themelis (1998) word that metals will be recycled nearly indefinitely. In contrast to polymer plastics and composites, the properties of metals can theoretically (nevertheless, usually not economically) be restored totally, no matter their chemical or physical form in a given part. Thus, metals used in gas cell stacks and the stability-of-plant are recyclable at much increased charges than different materials. Actually, based on information from both the United States Geological Survey and the British Metals Recycling Affiliation, recycling charges in their respective examine regions are fairly comparable with lead recycling leading at ~75% (dominated by lead-acid battery recycling), adopted by iron and steel, aluminum, copper and zinc recycling (Papp, 2005, Kumar et al., 2007). By mass, these metals can dominate gasoline cell techniques when considering each stacks and balance-of-plant and due to this fact offer substantial opportunity for gas cell hardware recycling.

Of explicit interest within the context of fuel cell metals recycling are steels, catalyst metals and metals used in batteries (for energy storage in the balance-of-plant). Steel recycling offers maybe the easiest path to achieving a excessive percentage of the mass of any fuel cell system to be recycled. This may apply, for instance, to the housings of most stationary gasoline cell systems (e.g. the standing enclosures round low-strain techniques and pressure vessels for prime-pressure programs) as well as to interconnects, stream discipline plates, tie rods, piping and heat exchangers in choose designs.

Also dominant on a mass basis, metals in gas cell system batteries could or may not supply a straightforward recycling possibility. If based mostly on lead-acid batteries (either typical or valve regulated), wide scale recycling can virtually be assured. In actual fact, the lead-acid battery business recycled >99% of the out there lead scrap from spent lead-acid batteries from 1999 to 2003, in keeping with a report issued by the Battery Council International (BCI) in June 2005 and making the lead recycling charge ranked higher than that of every other recyclable materials (Gabby, 2006). However, rising applied sciences akin to lithium ion batteries, nickel metallic hydride batteries and ultra-capacitors offer improved energy storage performance and, should they be extensively utilized in gas cells systems, promise to both reduce recycling opportunities or spur the development of a brand new recycling infrastructure.

In contrast to steel and the metals in batteries, catalyst household metals may be expected to be recycled on the idea of their value, as opposed to the dominance of their mass in gas cell systems. For instance, platinum household catalyst metals are at the moment quite successfully recycled from today’s vehicles (together with each platinum and rhodium). Bhakta (1994) notes that in today’s catalytic converters, the catalyst is housed in a stainless steel canister. Due to this fact, to recycle the catalyst, special machines have been developed to slit the canisters and remove the catalyst. Given an estimated enhance in the quantity of platinum group metals (PGMs) in gas cells of 15 to over 200 instances that of the catalytic converter for mobile fuel cell functions, it can be anticipated that similar technological development would comply with broad-scale deployment of fuel cells based on PGMs (Cooper 2003, 2004a).

In distinction, recycling charges for nonmetallic gas cell supplies are a lot lower than metals all through the world, even when contemplating all elements of recycling (reuse, remanufacturing, recycling and energy restoration). For the balance-of-plant, though gasoline storage hydrides, reforming media and insulation supplies have been recycled in laboratory and/or pilot plant settings, substantial development can be needed to help recycling for wide-scale gas cell deployment. For the stack, flow subject supplies such as graphite, carbon composites and stainless steel could be anticipated to be chemically and bodily altered during stack operation in ways that can prohibit reuse and remanufacturing. There may, nevertheless, be alternatives to make use of stream area materials in steel manufacturing or as insulation for gas cell or other electronic merchandise.

For the membrane-electrode assemblies a recycling process has been developed that begins from the separation of the completely different layers by an induced swelling of the membrane. Based on a non-organic solvent that doesn’t decompose within the presence of the catalyst and air, the fuel diffusion media and the catalyst layer can be separated from the membrane. After elimination of international cations, which are inserted within the membrane throughout operation, the polymer material’s performance is sort of recovered to the initial degree. Totally different results are observed for catalysts recovered from this recycling step; in a comparability to freshly prepared MEAs with original catalysts, MEAs made from recycled samples don’t give again the original performance and characterize clear outliers in efficiency. From these outcomes, a subsequent refining step of the catalyst is required with the intention to recycle the electrochemically lively materials. The person process steps are explained in more element in Fig. 5.1: Beginning from 60 kg MEA because the input one receives at the tip of the method a complete of 40 kg graphite material (GDL), 1.5 kg platinum powder (or different metals from the platinum group) and round 19 kg ionomer. The total worth of the mission is around $50 000 ensuing from the PGM powder plus an additional worth of $8-20 000. The last contribution severely is dependent upon the analysis of the recovered ionomer; currently there’s an absence of marketplace for these supplies which, nevertheless, is likely to alter once a broad market introduction of fuel cell technology has been achieved and a market for recycled ionomer exists.

Recycling through a pyrometallurgical course of focuses simply on the recovery of PGMs. In such a course of, the whole MEA (membrane, catalyst layer and diffusion media) are thermally transformed, skipping a preceding step separating the person elements. Subsequently, PGMs are recovered from the slag. However, the thermal course of bears the disadvantage of a number of fluorine compounds that is perhaps released and must be filtered rigorously from the exhaust gases.