Lanxess invests in water treatment technology Ion exchange resins and membranes in demand - cpp - chemical plants & processes

Lanxess invests in water treatment technology

Ion exchange resins and membranes in demand

Water treatment plants continue to be in demand. In line with this trend, Lanxess has in recent years invested in plants that produce ion exchange resins and reverse osmosis membranes. cpp caught up with Dr. Rita Dicke, Vice President Global Marketing/Product Management for ion exchange resins in the Liquid Purification Technologies business unit, to discuss current developments.

Dr. Dicke, what is the current trend in the market for ion exchange resins and RO membranes?

Dr. Dicke: External sources, such as the Global Water Market 2017 study carried out by GWI, indicate annual growth rates of around 10 % for reverse osmosis membrane technology and still around 4 % for ion exchange resins. That represents solid growth for a technology that has already been established for several decades.

How large is the annual demand for ion exchange resins worldwide?

Dr. Dicke: In 2016, global sales amounted to around 1.7 billion euros. Lanxess is one of the market leaders in this segment. Our strength is that our portfolio boasts membrane technology and iron oxide adsorbers in addition to ion exchange resins.

How is the ion exchange resin and membrane technology business embedded in the Lanxess group structure?

Dr. Dicke: The Liquid Purification Technologies (LPT) business unit, which is part of the Performance Chemicals segment at Lanxess, has subsumed the business with products used to treat water and liquid media. We represent the ion exchange resins from the Lewatit product line and the Lewabrane reverse osmosis membranes. Customers can design their water treatment plants using the Lewaplus engineering software.

In 2016, Lanxess also reorganised the marketing structure for its iron oxide adsorbers. LPT incorporated marketing of Bayoxide iron oxide adsorbers for water treatment – manufactured by Lanxess’ Inorganic Pigments (IPG) business unit – in its comprehensive portfolio. In order to harness synergy effects, LPT is now responsible for all water treatment products business. Unlike Lewatit ion exchange resins, Bayoxide cannot be regenerated but must be disposed of after use. Lewatit, Lewabrane and Bayoxide applications can be broadly split into four segments: industrial water treatment, drinking water, the chemical industry and food processing. Industrial water treatment accounts for around a third of the total annual sales.

How well is the business unit performing?

Dr. Dicke: Sales in the Performance Chemicals segment rose by 2.7 % in 2016 to about 2.14 billion euros. The development of sales in the LPT business unit contributed positively to this performance. Business is generally good: it’s a development which is being driven by a number of recent projects such as the expansion of our production plant at the Leverkusen site, the opening of a new facility in India and investments in reverse osmosis technology in Bitterfeld.

At which sites does Lanxess produce ion exchange resins and membranes?

Dr. Dicke: Ion exchange resins have been produced on an industrial scale in Leverkusen since 1956. We have consistently refined our products ever since. Styrene and divinylbenzene based polymers began to replace condensation resins as early as the 1950s. The first monodisperse polymers were developed at the start of the 1980s. Ion exchange resins have been manufactured at the Bitterfeld site since 1938. Reverse osmosis membrane elements were added in 2011. We have also had an ion exchange resin plant at our Jhagadia site in India since 2010.

What resin grades are produced at the various sites?

Dr. Dicke: Certain grades can be produced at more than one plant while others are mainly manufactured at a single facility. The same level of quality is maintained across all sites. If one plant is unavailable, another can take over, thus safeguarding our ability to deliver and ensuring flexibility for us and our customers. Phthalimide, which is required to make anion resins in Leverkusen, is an example of a site-specific technology. These resins have particularly high-quality properties and can potentially be used in the chlor-alkali industry, for example. They are utilised to treat the brines for chlorine production. Ion exchange resins employed as catalysts in the chemical industry are likewise manufactured at the Leverkusen site. These can be used to produce important plastics precursors. Other products from Leverkusen are the weak acid cation exchange resins (WAC resins) which are used in cartridge systems and improve the taste and quality of water.

Lanxess expanded the production plant in 2014 to include these cation exchange resins. What was the reason for this investment?

Dr. Dicke: One reason was the positive market development of these WAC resin grades. The demand for special cation exchange resins is growing by between 3 and 5 % each year. We added a fourth plant to the three lines that we already had for this product type. Overall, we have invested around 10 million euros in the site. This figure also includes the construction of a food-grade packaging unit for the resins which can serve all four lines.

Did the plant expansion result in any changes to the production process?

Dr. Dicke: The technology of the fourth WAC resin line is based on our existing plants. Of course, we are continuously improving the production process across all plants. The batch process begins with the production of polymer beads by emulsion polymerisation. A monomer and cross-linker mixture is placed in an inert solvent in a beading tank to form a finely distributed emulsion. Strict compliance with the reaction parameters is crucial to ensure that the polymer beads are of a high quality. The process steps for this purpose are mostly automated. Three-dimensional polymerisation and cross-linking take place in the tank. The non-functionalised polystyrene or polyacrylonitrile beads are separated from the liquid reaction medium via Nutsche filters and functionalised in the next phase. In the case of weak acid cation exchange resins, carboxyl groups are used. Due to their negative charge, the functional groups are capable of binding cations.

Why did Lanxess specifically decide to expand the Leverkusen site?

Dr. Dicke: We chose Leverkusen because the infrastructure of the relevant production plants was already excellent at that site and there was space for a fourth line. Another reason was the fact that the European market for resins used to treat drinking water is relatively large for us. However, there is also the option of manufacturing these products in India, so as to supply the Asian market from there. The resins produced in Leverkusen will primarily be utilised to make cartridges for treating drinking water. It was therefore also important to us that the food-grade packaging unit could serve all lines. This unit is vital for these types of WAC resin because no other industrial-scale methods are used by customers to purify the resins.

What structural measures needed to be implemented for the food-compatible filling unit?

Dr. Dicke: Packaging takes place in a separate building that is divided into black and white zones, the white zone being maintained under cleanroom conditions. Pipes are used to feed the resins directly from the tank into the packaging unit. Access to the white zone is closely regulated and the personnel employed there wear protective clothing. The white zone is supplied with filtered air and kept under positive pressure to prevent the ingress of impurities from the surrounding environment. Inside this 300 m2 hall, products are fed from several silos into big bags and drums on stainless steel pallets, so that they can immediately be weighed, labelled and transported. A rail conveyor system is employed instead of conventional forklifts. Before being transported to the adjoining storage and dispatch building, the containers are transferred fully automatically to wooden pallets and sealed in weatherproof film.

Are there already plans to further increase capacity, including at other sites?

Dr. Dicke: We are currently looking into potential areas for investment, but it is too early to confirm anything as yet.

What differentiates Lanxess’ ion exchange resins from the products of other manufacturers?

Dr. Dicke: An ion exchange resin is a product that inherently requires explanation, since it has a wide variety of applications. Unlike other manufacturers, we offer both monodisperse and heterodisperse resins. The performance characteristics of our products are what differentiates them from those of our competitors. What’s more, our service includes not only the sale of the product concerned but also the design of the water treatment plant using the Lewaplus software as well as technical advice.

What plants can be planned using the Lewaplus software?

Dr. Dicke: We started off designing ion exchange resin plants for water applications, but the range of products we can plan using Lewaplus software is regularly expanded. Following the introduction of reverse osmosis membrane technology, we incorporated it into the software as well. This is an advantage because the two technologies are often combined, especially in water treatment. The ion exchange resins are sometimes applied before the membrane elements in order to remove substances from the water that are harmful to the membrane. Ion exchange resins are also required following reverse osmosis to enable fine purification of water for applications requiring very high purity.

How do I know when I need to regenerate the ion exchange resin or even replace it entirely?

Dr. Dicke: Ion exchange resins are regenerated using a regeneration fluid such as 4% sodium hydroxide solution or sodium chloride solution that is passed through in the reverse direction. We are able to calculate the volume required for regeneration and design the cycles with a high degree of accuracy using our LewaPlus software. This allows a customer to plan the times between regeneration cycles and the anticipated costs of the regeneration process. The customer should also monitor the process continuously, for example by measuring concentrations in the purified stream. The length of time before regeneration becomes necessary depends to a large extent on the application. Resins can continue to be used for years in some applications. In others, however, they are subject to very high wear and regeneration is neither possible nor economically viable. As a result, their service life is much shorter. To check whether a particular resin is working correctly, customers can send us samples and we will then judge whether that resin can still be used or whether it needs to be replaced.

Does your portfolio currently include any new products?

Dr. Dicke: We have several new products for each segment, e.g. an acrylic resin for removing sulphates from citric acid, a new product for separating glucose and fructose and a mixed-bed resin for purifying water in heating systems. We have introduced Lewatit MDS TP resins for the chemical industry. MDS stands for “MonoDisperse Small”, which means that the average size of the ion exchange resin beads is very small. This resin delivers particularly good results, for example in chlorine electrolysis. The small beads make it possible to achieve enhanced properties for the selective removal of certain ions. The product is particularly attractive for new plants, which can be built specifically to facilitate its use.

Are you also developing customised Lewatit resins?

Dr. Dicke: In many instances, we are able to recommend a special ion exchange resin from our extensive product range to solve a customer’s problem. If we are unable to find an adequate solution, and if a corresponding order volume will result, then we will develop a resin to meet that customer’s needs. This is a simple business calculation.

Online search: cpp0317lanxess



The interview was conducted by : Daniela Held



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