Competition (98-07) Selective-Membrane Platforms:
Putting Membranes to Work for the Specialty Chemicals Industry

Selective-Membrane Platforms was created, in response to industry, to stimulate U.S. industry-academe-government partnerships for the technologically challenging R&D for agile and robust, high-selectivity/high-throughput, membrane-based separations technologies. Advances in separations technologies are needed to support more simple, efficient, safe, environmentally-benign, and economic manufacturing routes to high performance products in areas as diverse as pharmaceuticals and medical diagnostics, automobile parts, consumer electronics, and clothing. The program will leverage the R&D investment required for a combination of material science and manufacturing technology advances, and will bring together vertically-integrated teams including knowledge providers, technology developers, engineering companies, and chemicals manufacturers (including specialty, pharmaceutical, and intermediates). The goal of this program is a group of membrane platforms, i.e., families of membrane materials and modules that have broad ranging applicability (including difficult and high-value-added separations). The platforms developed during this program should also diffuse into many other applications, including commodities and petroleum refining. Individual projects should provide visible demonstrations of successful "real world" applications that will lower the hurdle rate for subsequent installations of related, efficient membrane technologies across the chemical and allied industries -- delivering added value to the combined $1.2 trillion value chains.

The word "separations" identifies a core process operation used in the chemical and petrochemical process industries to purify intermediate feedstocks that are critical for the sustained growth and competitiveness of most manufacturing industries. Advanced separations technology in the chemical and allied industries will supply product value-chains that include:

Although the U.S. chemical process industry (CPI) showed $372.3 billion in revenues in 1996, including a $18.0 billion balance of foreign trade, ⁽¹⁾ much of its output stream is not obvious to the consumer. It is through applications like those mentioned above that the CPI impacts our daily lives, and also supports the downstream innovations of other existing ATP focused programs .

The historic separations paradigm in the CPI has been based on simple equilibrium processes, primarily low selectivity, high-energy cost distillation. Although distillation is critical to the production of commodity chemicals, it provides too low a degree of selectivity for many emerging specialty chemicals applications, and its reliance on phase change (usually at elevated temperature) makes it intrinsically unsuitable for others. During the 1994-1995 time frame when an ATP "separations" focused program was first being formulated, industry indicated a strong and coherent need for breakthrough R&D efforts to produce mass separating agents ⁽²⁾ for the separation of materials with similar physical properties, or the concentration or removal of products or impurities from dilute aqueous or air borne streams. These new agents would need to be reliable in extreme environments (e.g., extremes in temperature, pressure, pH, or corrosivity), or deployable in hybrid processes (e.g., combining reaction and separation into a single unit operation). Since 1995 there has been continued support from the CPI and associated trade groups toward the development of an ATP focused program in separations.

Separations issues also pose critical technology barriers to the emerging biochemical process industry, which is poised at a threshold-of-ability to expand the value and impact of the U.S. chemicals industry. Whether through the use of fermentation or other enzymatic catalysts, new and efficient processes to alternative fuels (e.g., ethanol), chemical feedstocks (e.g., 1,3 propandiol for non-toxic antifreeze and novel polyester fibers), specialty chemicals (e.g., lactic acid for biodegradable packaging films), and custom chemicals (e.g., chiral intermediates for ethical drugs with fewer side effects) will depend on advanced separations technologies with high throughput and molecular selectivity in order to be economically viable in downstream applications.

A major milestone in establishing the current program scope and urgency was the Council for Chemical Research NICHE Conference 1997 Advanced Separations Technology, organized by participants from industry, academe, and government, and attended by a broad cross-section of industry and technology developers. It was at this meeting that industry put the challenge to ATP: create an initiative in highly-selective, membrane-based separations technologies that would finally catalyze the acceptance of membranes in core process operations of the specialty and commodity chemicals industry. Selective-Membrane Platforms is in direct response to this industry challenge.

Technology objectives. Although there is a wealth of innovative academic research on highly selective membrane materials, there are few examples of their implementation in the production of commercially important chemicals due to industry concerns over membrane reliability in real-world applications. In terms of technology objectives, individual projects in this focused program are anticipated to deliver step-change improvements in membrane performance, resulting in:

Business objectives. The business objectives of candidate projects should be to deliver specialty chemicals that will:

Program objectives. Beyond the results of individual projects, the program objectives of Selective-Membrane Platforms are to:

Why ATP. The vision of Selective-Membrane Platforms is to use a focused ATP technology development initiative to leverage the past research investments (private and public) in an academic-industry-government partnership to develop breakthrough-platform, membrane-based technologies that will be proven at pilot or pre-commercial scale. Such developments will significantly lower the technology-related barriers to industry acceptance of membrane approaches to core-process separations operations. ATP involvement in this area is critical because:

Program Implementation. Since it is anticipated that most proposals will come from newly-forming joint ventures, a (non-obligatory) pre-proposal process will be used to stimulate potential proposing groups to solidify their ideas and divide responsibilities early. This process was found highly useful in organizing and strengthening joint ventures applying to the 1997 ATP focused program Technologies for the Integration of Manufacturing Applications. Although submission of pre-proposals will not be mandatory, feedback will be given promptly on degree of apparent technical risk; conformity to the concept of technology-platform development and impact on future acceptance of membranes in industrial applications; potential for broad-based benefits; business and commercialization plans; and organizational structure and commitment.

Although applications from "single applicants" will be equally considered, the minimum expectation of this solicitation is to leverage ATP funding to support five to seven "joint-venture" projects to move specific, high-selectivity membrane materials from proven laboratory feasibility through pilot scale performance testing. A typical project might be of order $3.0 million per year, extend over four to five years, and provide over 50% cost-match.

The pathways to all consumer products rely on creating specific organizations of predominantly carbon (C) and hydrogen (H) and some nitrogen (N) and oxygen (O). For example, the petrochemical industry produces the mixtures of C_n hydrocarbons found in oil fields, separates the C₂ fraction from the higher- and lower-C_n fractions, and then further separates ethane from ethylene. The chemical process industry (CPI) then carefully adds N and O, for example, to make acrylonitrile monomer that is polymerized to make polymer resins. These polymer resins are then further processed in downstream manufacturing facilities to make the components for final assembly into consumer goods, such as acrylonitrile fiber as the starting point for carbon fibers used in composites for aircraft and bicycles among other applications. Other intermediate chemicals are also continually being developed for future products, such as, automotive-dash fascia and bumpers for next generation vehicles and solid polymer electrolytes for lightweight, high power density batteries used in portable electronics.

The CPI plays a critical role in directing the important chemical transformations and separating/purifying the desired products from a complex matrix of unreacted feedstock, by-products, and waste. In this role, the CPI's position in the value chain lies between the upstream technology developers who have the knowledge and tools to develop new separations/process paradigms, and the downstream product manufacturers who capture most of the added value. Examples of downstream product areas are:

• Critical advanced materials for the aerospace industry include carbon-carbon and carbon-epoxy composites. Economical access to ultra-pure acrylonitrile would enable the manufacture of ultra-thin carbon fibers for the creation of stronger/lighter weight composites for airframes and aircraft brake pads.

Industry need. U.S. manufacturers in all industry sectors are looking for routes to higher-performance or lower-cost products to sustain their competitive position in the global marketplace. These routes will be founded on new separations materials and processes in the CPI that will enable the creation of:

• High performance processes such as a permselective membrane supporting a dehydrogenation catalyst to simultaneously form desired products and remove the by-product hydrogen. Thus the reaction can proceed to higher yield and achieve superior economics.

To achieve industry acceptance, any new separation platform must provide significant processing cost reductions by:

The ability of the CPI to meet these emergent demands for high-performance, low-cost products rests on their ability to "find" separating agents compatible with appropriate reaction processes and reliable under real-world operating conditions. Today this is generally accomplished by contract research to technology developers. However, in this scenario, the CPI shoulders both the technology risk (i.e., if the new separating agents fail) and the market risk (i.e., that the new or improved chemical feedstock will not provide the downstream manufacturers with the anticipated economic advantage) without a corresponding share of the added value introduced by these high performance specialty chemicals.

Strengths, Weaknesses, Opportunities and Threats. The world leader a decade ago, the U.S. CPI is threatened by four external forces:

The future sustainability of the CPI has been weakened by the decade-long trend toward down sizing in its corporate research efforts. Although currently spending approximately $12 billion on R&D, research has been moved into business units with short term, product improvement foci, and development efforts redirected toward customer service. The research arm of many companies today consists of a small group of technology watchers who advise operating units on very specific short term projects. Alongside the cuts in R&D staffing, reductions in capital budgets force any incremental process development to be aligned with existing, fully-depreciated equipment. Although this trend has not been significantly reversed, innovators in the CPI are now turning to partnerships with industry-sponsored university centers of excellence, small technology developers, and independent research organizations and national laboratories to meet their longer-term R&D needs. Despite the leveraged research funding from NSF, DOE, EPA, DOD, and the federal SBIR programs, industry's focus on specific niche problems and their shotgun approach to technology development does not significantly further the general acceptance of membranes in core-process separations operations.

The strongest long-term position of the U.S. CPI is in specialty chemicals. ⁽⁴⁾ In the global chemical industry, approximately 95% of production mass is commodity chemicals (where margins are measured in pennies per kilogram and labor, energy, and capital costs play a key role in competitiveness). However, approximately 30% of industry profit is provided by the about five-mass-percent that is specialty products. These are high value-added chemicals with market growth driven by developments in the pharmaceutical, agrochemical, semiconductor, paper, and plastics industries.

Consider, as an example, Asia's rapidly-modernizing economy which today consumes one-third of the world's plastics production. Chemical producers worldwide are planning new plants in Asia to provide the high-purity and high-performance monomers demanded by these rapidly growing economies. However, to capture these opportunities U.S. chemicals firms need competitive technologies. For example, to an outsider the timing of the 1995 $1 Million Monsanto Challenge coincided with a desire for improved separations technology for the recovery (for reuse) of mixed organic compounds, salts, and acids from the process streams in a world-class acrylonitrile plant (i.e., the starting point of a polymeric-fiber value chain) for China. It is possible that the loss of the recent bid was partially due to the high unit cost associated with their current technology, the lack of availability of an improved process, and their corporate standards of behavior and technology. ⁽⁵⁾ There are two important ramifications of this outcome:

As emerging foreign specialty chemicals manufacturers adopt new separations technologies in green-field plants, U.S. manufacturers will find it more difficult to compete. This threat to the prominence of the U.S. chemicals industry is exacerbated by:

The historic separations paradigm in the CPI has been complex, high energy cost distillation columns, but the high temperatures and low selectivity of distillation make it intrinsically unsuitable for many specialty intermediates. Chromatographic resins offer high molecular selectivity, but have limited applicability in high-throughput applications. Although new membrane materials are beginning to have the required selectivity and show potential for high-throughput applications, they do not have a proven reliability in CPI applications. ⁽⁶⁾

A major point made at the Council for Chemical Research NICHE Conference 1997 Advanced Separations Technology was that there are few examples of membrane implementation in commercially important commodity and specialty chemical applications due to substantial technical (e.g., membrane selectivity and reliability) and non-technical barriers. No one in the U.S. chemical process industry wants to be the first to replace functional unit operations with an "unreliable" membrane system -- they would all like to be second. Broad deployment of membrane-based systems in the areas of industrial gas purification (e.g., nitrogen for cryogenic and inerting applications; oxygen-enriched air for welding and metal processing) and solids recovery (small scale dairy and electroplating applications) are strong indications of industry's willingness to rapidly adopt successful new technologies where there are no viable alternatives.

A wealth of technological innovation was presented to ATP through white papers and workshops, and can be independently measured by patent and publications activities -- the level of innovation within the membrane research community is very high. Between 1990 and 1997 the PTO database yields 2542 patents issued for membranes. The number of research papers published in just the Journal of Membrane Science has increased exponentially over the past 5 years (with a doubling period of 2 years). Based on a cursory overview, some 20% of these patents and publications would fall into categories within the high-selectivity paradigm of Selective-Membrane Platforms.

Other points to be noted are the significant number of technical meetings that are either completely devoted to membrane science and technology (e.g., North American, European and Japanese membrane societies have yearly meetings) or have a significant number of sessions on that topic area (e.g., American Institute of Chemical Engineers and American Chemical Society). Technology development in this area is truly competitive. In addition to work at all major universities around the world, there are many government or government-industry-academe partnerships pursuing separations technology that is membrane-based.

Nearly every major chemical and petroleum corporation has a separations group, and many research universities now have major industry- and government-funded separations programs (e.g., the Separations Research Program at the University of Texas, Austin and the Center for Separation Using Thin Films at the University of Colorado, Boulder) -- however, the academic work is often far removed from commercialization and the industry work is often focused on incremental improvement for specific applications.

Program scope. Based on input from 50-plus industry white papers, several ATP-sponsored workshops on separations, and industry- and professional association-sponsored meetings there appears to be broad consensus on industry's need for the following innovative membrane-based technology platforms -- new membrane materials or process conditions that will provide substantial improvements over current selectivity-speed capabilities.

• Chemical vapor deposition and grafting within membrane pore structures are possible means to vary pore size by several nanometers (nm). Careful selection of the base membrane material and processing conditions provides tunability over the range 1 nm to 200 nm -- resulting in a highly variable manufacturing platform for multiple end-user applications; and
• Electrochemical membranes or membranes made from conducting polymers (e.g., polypyrrole or polyaniline) offer the end-user the opportunity to continuously tune process selectivity on-line in response to changing feed conditions or product specification for increased process agility.
• Material and manufacturing challenges are significant in both approaches.

4. Membrane surface and process modifications. Polyamide thin-film composites and electron-beam grafting offer the potential to spatially alter membrane surface tension and/or chemistry, and provide a starting point for the development of imprinted membranes for molecular-recognition separations. Also micrometer-scale surface texturing, inter-membrane spacer designs, vortex flow concepts (e.g., hydrodynamic instabilities), spinning surfaces, and integral "scrapers" offer promise to decrease membrane fouling and provide more efficient designs for high-solids processing. The challenges are in matching membrane and module materials with economical manufacture, designing innovative processes (from engineering design companies), and implementation (by end users).

Proprietary examples of each of the above mentioned families of membrane innovation exist. Their technology development status ranges from proof of feasibility, to bench scale prototype, to proven small-scale applications. However, to the best of our knowledge, there are few examples of such innovation currently deployed in a commercial U.S. application for the manufacture of specialty or commodity chemicals. ⁽⁸⁾

Examples of "enabling" technology. Each family of novel membrane "systems" mentioned above represents a breakthrough technology platform. If the materials and manufacturing challenges can be solved for a lead application, there are potential platform extensions that will leverage this base-technology development in related separations challenges, for example:

• New antibiotics and therapeutics are being identified from novel drug discovery processes, including combinatorial chemistry techniques. The synthesis approaches are not limited to the traditional fermentation techniques but will include traditional organic synthesis approaches as well. In order to simultaneously overcome reaction equilibrium limitations and the expense and complexity of multiple liquid-liquid solvent extraction steps a membrane reactor/separator can be considered. The membrane needs to be solvent resistant, inert to the redox reaction species, and very selective because multiple steps each need high recovery (e.g., in a 48 step synthesis, 98% yield at each step results in a total yield of less than 40%).

• ATP is sponsoring the development of solid electrolyte membranes that integrate oxygen separation and catalytic oxidation (e.g., selective partial oxidation of hydrocarbons). Extensions of this platform to other high-temperature membrane reactors may be possible. This would include petrochemical processes such as dehydrogenation and hydrotreating of asphaltenes. Other extensions of this platform could include the development of improved synthesis processes where current catalyst and reactor technology is inadequate, or where the selective removal of reaction intermediates/products will enhance yield or catalyst lifetime. One potential application might be an improved processes for synthesizing new families of biodegradable polymers based on polymers of propionic acid (a $20 billion opportunity for replacing polyethylene in certain applications) formed from ethylene oxide and carbon monoxide versus the current route using expensive and toxic lactone.
  
• High-selectivity, high productivity, robust membrane materials may be used to help process dendritic polymers (e.g., "3-D snowflakes") for uses as a polymeric aerogel to provide low-dielectric insulating layers between silicon layers in multi-layer chip designs. Such low-dielectric insulators are becoming increasingly important for the anticipated high-density circuits along the SIA Roadmap. Similar advanced membranes might also be useful for replacing chromatography in the recovery of fullerenes and carbon nanotubes (i.e., for possible uses in composites and non-linear optical materials) when potential commercial applications generate increased production demand.
  
• Chemical-specific membranes have the potential to provide effective separations of optical- and chiral isomers for a wide variety of products, including albuterol (asthma drug) and ditiazim (calcium ion blocker), L- and D-glutamic acid (food flavoring), and stereo-monomers for liquid crystal polymers (active matrix displays and high strength optical fibers). Chemically-specific membranes are being pursued using molecular imprinting and controlled cross-linking. Developments will have uses across the spectrum of specialty chemicals, pharmaceuticals, and agrochemical products.

In funding projects aimed at overcoming the technical challenges associated with these ideas, ATP would require that the proposed solutions include the development of a reliability-proven platform technology that could be adapted (e.g., by modifying the incorporated agents) for superior, cost-effective solutions to pervasive separations problems shared by the chemical, petroleum, mining and metal finishing, pulp and paper, semiconductor processing, food, agrochemical, and biochemical processing industries. The development of such selective-membrane based platforms will allow process industry engineers to choose appropriate solutions to provide more effective routes to product and profit, and ensure broad technological impact. The recently implemented Separations Tool Advisory (developed as a part of the Clean Process Advisory System of the AIChE Center for Waste Reduction Technologies) will provide a mechanism to make information about these emerging separations processes and related product design data broadly available to design engineers and end users.

Separation issues are critical at all stages in moving from raw materials to final products with the highest value at a minimum of cost, and with a minimum of impact to the air, water, and land that industry shares as part of the larger society. Separations processes can constitute up to 90% of the processing costs in the biotechnology industry, especially for high-value pharmaceutical products, and 40%-70% of capital and operating costs in high-volume chemicals applications; and control the creation of high-performance products that are dependent on feedstock availability, purity, or cost for their competitive edge. Users of specialty-separation technologies include the electronics, metal finishing, pharmaceutical, plastics & rubber, health care, food and beverage, and biotechnology industries. Users of high-volume-separation technologies include the basic process industries: chemicals, agrochemicals, pulp & paper, water purification, extraction industries, and oil refining (petroleum) -- industries that provide the downstream manufacturing sectors with industrial feedstocks. Together, these two user groups of separation technologies represent about $1.2 trillion in product shipments and over $500 billion in value-added to the U.S. economy. ⁽⁹⁾

Partnerships. An ATP focus program in membrane separations will accelerate economic growth by fostering the formation of multi-disciplinary teams, typically including an academic innovator, a small business technology developer, a system integrator, and a major chemical or pharmaceutical manufacturer to share the risk in speeding new technology to large scale; and by encouraging partnering between separation-technology developers and end-users to create new value-added markets.

Potential contributors to the vertically integrated partnerships anticipated by Selective-Membrane Platforms might include:

Business goals. The program focus on core-process applications guarantees that the new-platform technology solutions developed under this initiative will be applicable to a broad cross-cut of industries. Direct impact on the U.S. economy will be measured by the reduction in unit costs (i.e., raw material, energy, capital, operating and disposal) and increase in production capacity; and by the creation of new markets based on new- and high-performance materials. Indirect benefits in areas of enhanced environmental quality are also anticipated. The aim of Selective-Membrane Platforms is to develop breakthrough separations-technology platforms that push beyond the current efficiency frontier (the existing tradeoff relationship between selectivity and productivity) for a variety of processes. In this section we try to define "breakthrough performance" in terms of suitable business goals of candidate proposals.

High performance products. New- and higher-purity products produced by the chemical industry can open new markets and enhance the performance of products manufactured by customers in the electronics, optics, and health care industries.

High performance processes that reduce processing costs per unit product by 20%-50%. Although this goal might be reached through: improved capacity, utilization of lower quality feedstocks or raw materials, reduced energy consumption, and lower pollution abatement costs, given the large size (capital investment) of chemical process plants and relatively cheap energy costs in the U.S. today, significant cost reductions for existing plants will generally be achieved through increases in capacity:

Achieving these business goals will have secondary economic benefits through the sales or licensing of U.S. technology to countries expanding their chemical, petroleum, pulp and paper, mining and metals finishing, and food and beverage manufacturing sectors; through the generation of spin-off separation technologies usable in consumer markets; and through the exportation of advanced environmental technologies into the rapidly growing $150 billion world-wide market for water and air pollution control technologies. ⁽¹³⁾

Membrane-market segmentation. Although markets are often segmented by application (pharmaceutical vs potable water), media (air, aqueous & organic solvent), and materials (inorganic vs polymer) there are about 50 U.S. companies involved in the $2.5 billion worldwide market for membrane materials and modules.

The material and manufacturing costs of the separating agents (i.e., the membrane itself) represent about 30% of the cost of a membrane module. Sales of full membrane-based operating systems are currently in the $4 billion range, and are projected to grow to over $10 billion by 2000 (the added value from the system developer is of order 2.5-fold to 5-fold the value of the membrane and/or module).

U.S. Sales of Membranes and Modules ($ million)⁽¹⁴⁾

Industry Commitment

Opportunity for ATP to Make a Significant Difference

Endnotes