Demineralization cartridge / VE cartridge

A demineralization cartridge / VE-cartridge is used to produce so-called demineralized water in small quantities of up to 4 m³/week; beyond this, demineralization systems that can be regenerated automatically are generally used. In this process, all ionogenic substances are removed from the input water, often city water, and replaced with H2O. This produces a high-purity demineralized water (also: DM water or “forklift water” or “battery water”) for industrial purposes with a conductance of < 0.1 µS/cm in ultrapure water applications up to 0.056 µS/cm.

High-purity water is often required in industrial processes, e.g. in laboratories, for post-purification of pre-purified water or when filling forklift truck batteries. The typical parameters of the available water, usually city water “from the tap”, are generally not sufficient, as particularly limescale deposits of the hardness formers calcium and magnesium are disruptive in the processes. The VE cartridge or demineralization cartridge contains an ion exchanger resin Mixture of cation exchanger resin and strongly basic anion exchanger resin, typically in a ratio of 40:60, so-called mixed bed resin. The strongly acidic cation exchanger removes the cationic ion loads such as sodium, calcium, magnesium and also the copper permissible according to Drinking water ordinance up to 2.0 mg/L. The strongly basic anion exchanger removes anionic ion loads such as corrosive chlorides or sulphate. Within the scope of their respective capacities, the cation exchanger releases H+ ions in exchange and the anion exchanger releases OH- ions in exchange. Together, H20is produced in the outlet of the system instead of the ions in the inlet water. Due to the mixture of the two ion exchangers, the removal of ionogenic substances ensures a low conductance value of typically < 0.1 µS/cm at the outlet of the demineralization cartridge / VE-cartridge. The capacity of the cartridge depends on the amount of resin used, its type and the composition of the feed water (salt load). Typically, however, a capacity of approx. 2 m³ of demineralized water can be expected from the average city water of around 350-550 µS/cm with a 30L demineralization cartridge and approx. 4 m³ of demineralized water with a 50L demineralization cartridge. Full capacity utilization can be achieved by connecting 2 VE cartridges in series. After replacing the loaded 1st VE cartridge, the 2nd VE cartridge moves to the 1st position Once the capacity of the demineralized water cartridge is exhausted, it is regenerated externally as an ion exchanger regeneration service so that it is not overrun.

The demineralization cartridge does not generate any waste water during the production of demineralized water as part of the process water treatment. However, when using the demineralized water product from the demineralization cartridge for operational purposes (e.g. rinsing of workpieces), operational wastewater is still generated, the indirect discharge of which into the municipal wastewater treatment plant is subject to treatment and approval.

A common application is the production of demineralized water, e.g. in an industrial or commercial enterprise for diluting concentrates, preparing chemical baths or rinsing sensitive parts with a conductance of < 30 µS/cm salt load from city water or the filling of forklift batteries (according to ZVEI leaflet requirements for electrolyte and refill water for lead batteries) by means of a demineralization cartridge, so-called VE-cartridge. The chemically relevant part of the VE cartridge consists of a mixed bed resin, e.g. Lewatit NM 60 or Purolite MB400, with a proportion each of strongly acidic cation exchanger, so-called SAC (sulphonic acid exchanger on styrene-divinylbenzene copolymer) and a strongly basic anion exchanger, so-called SBA (quaternary amine exchanger on styrene-divinylbenzene copolymer). Both resins are mixed together to form the so-called mixed bed resin in the demineralization cartridge, which is used to demineralize tap water or city water. [/fusion_toggle][fusion_toggle title="Further process engineering expansion stages for VE cartridges: " open="no" class="" id="" fusion_font_family_title_font="var(--awb-typography4-font-family)" fusion_font_variant_title_font="var(--awb-typography4)" title_font_size="var(--awb-typography4-font-size)" title_line_height="var(--awb-typography4-line-height)" title_letter_spacing="var(--awb-typography4-letter-spacing)" title_text_transform="var(--awb-typography4-text-transform)" title_color="var(--awb-color5)" hue="" saturation="" lightness="" alpha="" fusion_font_family_content_font="var(--awb-typography5-font-family)" fusion_font_variant_content_font="var(--awb-typography5)" content_font_size="var(--awb-typography5-font-size)" content_line_height="var(--awb-typography5-line-height)" content_letter_spacing="var(--awb-typography5-letter-spacing)" content_text_transform="var(--awb-typography5-text-transform)" content_color="var(--awb-color5)"] To prevent only weakly bound ions such as chlorides, hydrogen carbonate or silicates from breaking through, two VE-cartridges or demineralization cartridges are often connected in series. The first cartridge is equipped with a conductivity measurement in the outlet. As soon as the conductance rises, silicic acid and chlorides have already broken through, but these have been absorbed by the 2nd demineralized water cartridge. A carousel exchange takes place, in which the first demineralization cartridge is removed for ion exchanger regeneration and the second demineralization cartridge is placed in the leading position and an optional 3rd demineralization cartridge takes over further post-cleaning.

In special applications, the mixed bed resin used in the demineralization cartridge can be replaced by a so-called UPW Ultra Pure Water ion exchanger resin for the production of ultrapure water, e.g. Amberjet UP6040 or Lewatit UP 1292 MD. This is characterized by higher networking and a higher capacity. Under optimum conditions, such a demineralized water cartridge can purify the water to the lowest technically achievable conductance value of 0.056 µS/cm or 18.18 MΩ-cm (based on the salt content). In the context of ion exchanger regeneration, however, it should be noted that this is not a pool regeneration, but a proprietary regeneration in order to avoid cross-contamination with other resins that may have poorer properties. The advantage of this separate treatment for demineralization cartridges in the mixed-bed polisher ion exchanger application in ultrapure water production is the controlled quality assurance in the context of the increasing ageing of the ion exchangers.

Another common application is the filling of heating systems with demineralized water in accordance with VDI 2035 with low-salt operation (according to the heating system manufacturer). Typically, demineralized water cartridges in steel containers are connected to the ctiy water connection and fill the heating circuit with demineralized water 0.11 °dH, <100 µS/cm at pH 8.2-8.5 (aluminium and possibly also copper pipes) or up to pH 10 with stainless steel pipes. The exhaustion of the demineralized water cartridge is displayed on the connected conductivity meter. As a rule, this is a loan of the cartridge including regeneration. [/fusion_toggle][fusion_toggle title="Application 3: Mixed bed polisher for ultrapure water production" open="no" class="" id="" fusion_font_family_title_font="var(--awb-typography4-font-family)" fusion_font_variant_title_font="var(--awb-typography4)" title_font_size="var(--awb-typography4-font-size)" title_line_height="var(--awb-typography4-line-height)" title_letter_spacing="var(--awb-typography4-letter-spacing)" title_text_transform="var(--awb-typography4-text-transform)" title_color="var(--awb-color5)" hue="" saturation="" lightness="" alpha="" fusion_font_family_content_font="var(--awb-typography5-font-family)" fusion_font_variant_content_font="var(--awb-typography5)" content_font_size="var(--awb-typography5-font-size)" content_line_height="var(--awb-typography5-line-height)" content_letter_spacing="var(--awb-typography5-letter-spacing)" content_text_transform="var(--awb-typography5-text-transform)" content_color="var(--awb-color5)"]For the production of ultrapure water, so-called mixed-bed polisher filters, i.e. a demineralization cartridge, are often used subsequently for further fine purification after appropriate pre-treatment by a reverse osmosis system, possibly with electrodeionization, or a demineralization system. These are demineralization cartridges, often with a higher quality mixed bed resin, which represent the final fine purification stage in ultrapure water production. These ion exchangers are then regularly regenerated externally as proprietary regeneration, i.e. without mixing with other customers and applications. This also has the advantage that the ageing of the resin bed can be controlled.

Due to the low load on the mixed-bed ion exchangers, volume flows of more than 100 m³/h can also be fine-cleaned as part of the external regeneration of UPW mixed-bed polisher ion exchangers.

Fully demineralized water(VE-water) or deionized water (DI water) is not defined separately as such, but its parameters are derived from the customer-specific process. The main aim is to avoid stains or deposits during subsequent use.

Typically, however, the following conductance values are required at the outlet of the demineralization cartridge or VE-cartridge: Semiconductor 0.08 µS/cm, general laboratory purposes 0.1 µS/cm, forklift water or battery water when filling: 30 µS/cm.

Products

VE cartridge 50L, 30L, 20L stainless steel
VE cartridges in various sizes
Demineralization cartridge 30L

A demineralization cartridge is recycled in the central treatment plant using 3-column technology as part of the external ion exchanger regeneration service. For this purpose, an (open) pool regeneration is usually carried out (optional: proprietary regeneration or closed-pool regeneration, e.g. for high-quality Polisher mixed-bed resins from the production of ultrapure water), in which several demineralization cartridges are initially combined into one batch. Pre-treatment is carried out, followed by separation into the two resin components – strongly acidic cation exchanger and strongly basic anion exchanger – in different treatment columns, also to avoid cross-contamination during regeneration. The cation exchanger is regenerated separately with hydrochloric acid, the anion exchanger with caustic soda, as the different regenerating agents require separate regeneration. After subsequent rinsing, the two parts are mixed again to achieve a homogenized resin mixture and filled back into the cartridges. Disposable UPW (Ultra Pure Water) ion exchangers, so-called mixed-bed polishers, from the production of ultrapure water can also be regenerated in special processes.

By using a demineralization cartridge, no waste water is produced at the point of use.

  • VE cartridge bodies in GRP with PE inliner, vinyl ester, PP or stainless steel
  • Connections in PP or PVC with d25, d32 or on customer request (e.g. Gardena)
  • Mixed bed ion exchanger from Lanxess Lewatit NM 60 or Purolite MB 400
  • Ultra Pure Water resins e.g. Ambertec UP6040 or Lewatit UP 1292 MD optional for ultrapure water production as mixed bed polisher ion exchanger e.g. after electrodeionization
  • Other mixing ratios of cation exchanger resins and anion exchanger resins optional
  • Temperature resistance up to 70°C optional
  • Integration into existing customer systems possible
  • Vacuum-resistant cartridges optional
  • Modular, maintenance-friendly design according to customer requirements with various optional expansion possibilities, e.g. with feed tanks, collecting trays, simple feeding to redundant FU duplex pressure booster stations, pre-filtration, pressure difference display, actual production data acquisition, separate silica cleaning.
  • VE cartridges regeneration by forwarding agent or by tour as an exchange on site or optionally as a proprietary regeneration

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