Page 166 - CW E-Magazine (10-6-2025)
P. 166

Special Report                                                                                                                                                                   Special Report



       High-tech rubber in the service of the energy transition                                                      plate-type  shape  such  as layered                                 are encapsulated in two layers of
                                                                                                                     silicates or graphites can help to addi-
                                                                                                                                                                                         this  material;  when  the  fi lm  melts  it
             in Düsseldorf is the world’s                                  DR. STEFAN ALBUS                          tionally reduce gas permeation.                                     perfectly  envelops the cells. EVA is
             most relevant  trade fair for                                                                                                                                               extremely translucent and weatherproof
       K not only the plastics but also                                    Freelance trade journalist                   To ease hydrogen transport, alter-                               and boasts a wide processing window;
       the rubber industry. Sustainability and                            phide and ammonia. This is why such        native carrier media have also been under                           it is not a classical elastomer but can –
       saving resources, however, are also                                materials as EPDM (Ethylene-Propy-         discussion as of late,  such a gaseous                              depending on its EVA content – be con-
       burning issues here  that  nobody  can                             lene-Diene-Rubber) membranes are           ammonia (NH ) at room temperature)                                  sidered an “elastomer-similar” material
                                                                                                                                 3
       ignore. One more reason to shed some                               used in biogas production plants, along-   which is easier to liquify and store. This                          by all means. There are also approaches
       light on just how important rubber is in                           side their rivals like double membranes    application also requires low-tempera-  of its problematic resistance to weather-  to replace EVA fi lms from fossil sources
       “green” applications in the run-up to                              from polyvinyl chloride (PVC)-coated       ture and especially  alkaline-resistant  ing and ozone. Instead, NBR is the  with alternatives that contain a percent-
       K 2025.  Our  society is faced with   gas  is  also  still considered an interim  polyester wovens. Both materials have   high-performance rubbers.  preferred option  for  full-rubber rotary  age of bio-based “sugarcane ethylene”.
       completely new challenges due to climate   fuel for comparatively carbon dioxide  their pros and cons in this application;                      shafts. In radial shaft gaskets you will
       change. Does the material that is   (CO )-low energy production. At pre-  but  EPDM  rubber  is  a  little more   Needless to say, hydrogen already  also often fi nd ozone-resistant HNBR,   To make sure the solar panels stay
                                            2
       rubber, invented over 180 years ago,   sent, Germany sources plenty of natural  fl exible, and easy to recycle.  serves  its purpose  in fuel cells very  which, in addition, also withstands  in  place  on  today’s  stylish  fl at  roofs,
       still play a role here?           gas from the USA where around 88% of                                        reliably. But there is no such thing as a  temperatures as high as 170°C for short  installers like to use EPDM mats. These
                                         this energy carrier are obtained through   While the tasks described for highly   “one-fi ts-all”  sealing  material  for  fuel  periods.  With the corresponding rein-  provide additional support on slippery
          Of course!  Often  it  is precisely   fracking.  The components needed for  advanced rubber materials so far might   cells: for  instance, there are alkaline  forcement HNBR can also be used for  ground and prevent the modules from
       those materials  made of particularly   this application also include extremely  be addressed with half-way “traditional”   and phosphoric acid, polymer electro-  large-diameter bearings, and thanks to  shifting over time. Speaking of build-
       advanced synthetic rubbers  that come   high-performance hoses  that can also  approaches, things get really  tricky   lyte and high-temperature  fuel cells.  its oil-resistance even in grease-lubri-  ings: needless to say, heat pumps can
       to the fore here.                 withstand contact with aggressive  with hydrogen. Hydrogen only liqui-      Here, too, elastomer-bonded sealing  cated main bearings.           hardly do without rubber either. How-
                                         liquids, which are injected into the rock to  fi es under normal pressure at extremely   materials with a high content of special                ever, this application calls for (weather-
       Geothermal                        release the gas trapped there. For these,  low temperatures.  Which  is why the   fi llers are already used for sealing tasks.  The cables transmitting power  resistant) sealing gaskets and hoses,
          One such application for rubber of   multi-layered  products are preferred  sealing materials for a future hydrogen                          from offshore wind parks can become  which  are  also  suffi ciently  fl exible  at
       this kind is heat recovery from deeper   because their inner layers consist of an  economy should be designed to cover   Wind power             very hot. This is why rubber materials  lower temperatures; but also for vibra-
       layers of the earth. After all, geothermal   acid-resistant synthetic rubber; for the  a wide temperature range (-40 to over   Wind turbines are growing to ever  with a higher temperature  resistance  tion-dampening rubber mats that reduce
       drilling can reach depths of 1,000 to   outer layer rubber grades with excellent  +80°C). In addition, high pressures are   greater heights. Today, they can achieve  are required, like EPDM in addition to  undesired pump vibration.
       even 3,000 metres. In the process   wear and ageing resistance are used.  to be withstood.                    nominal outputs of over 10-MW with  HNBR.
       so-called packers are deployed – roughly                                                                      rotor diameters of 150-m to 220-m.                                     So, rubber is anything but an
       1-metre-long downhole devices used   One feared hazard in natural gas   The problem here is that non-polar    In this application, offshore locations,   And let’s not forget, rubber is not  “obsolete” material. Without extremely
       to seal the space between the wellbore   extraction are uncontrolled, violent  H  molecules can permeate and thereby   UV radiation,  ozone (not rarely pre-  only in demand for operating these sys-  performance rubber grades the energy
                                                                            2
       casing and the drilling tubing; these   releases of gas from deposits, known as  impair  conventional sealing materials.   sent in the surroundings of electrical  tems – it is also already required for the  transition  and  fi ght  against  climate
       consist, amongst others, of heat-resistant   “blowouts”. These are  prevented  with  If hydrogen gradually  deposits in the   equipment),  salt water and strongly  manufacturing of the rotors from glass-  change would not work.
       rubber. In the spaces isolated by these packers,   the help of so-called blowout preventers  sealing material explosive decompres-  fl uctuating temperatures all make high  fi bre reinforced elements with sections
       temperature or pressure measurements can   (BOPs),  i.e., extremely hard-wearing  sions can occur that  destroy the  seal-  demands on the elastic materials  of silicon, butyl or EPDM rubber.  At K 2025 Rubberstreet will again
       be taken for example. Incidentally, in such   rubber seals – which also survive con-  ing gasket. And these sealing  gaskets   deployed. On top of this, ultimate fl ame-          serve as the showcase for the innovative
       deep  drilling –  in geothermal projects   tact  with hydrogen sulphide and both  are urgently needed in the hydrogen   proofness is required because nacelles  Solar systems     power and operational excellence of the
       but also in the crude oil sector – engines   corrosive and abrasive  media.  These  economy: for electrolysis, in valves or   that have caught fi re can practically not   Photovoltaic  (PV) systems, of  elastomer industry. It has already been
       with a spiral rotor in a stator housing are   seals are very expensive and therefore  membranes, for transport in tanks and   be extinguished. These nacelles include  course, also need sealing gaskets, that  the fi rst point of contact and orientation
       used that are clad with rubber inside. The   expected to last accordingly.  This is  pipelines and, of course, in fuel cells.  components for the vibration isolation  keep the modules aligned and prevent  for all those seeking information about
       rubber components used here are virtually   why HNBR is a preferred solution.                                 and elastic bearing of the generator:  water ingress. Vertical sealing gaskets,  elastomers (rubber and TPE) at K since
       a  Who’s  Who of advanced rubber                                      In actual  fact, truly effective  H -   rubber buffers can be found at the con-  for example,  that keep the offset bet-  1983. The patronage of Rubber Street
                                                                                                         2
       applications technology: Nitrile Butadiene   Biogas and hydrogen   tight  rubber sealings are still  the sub-  nections between the rotor blades and  ween several  PV modules,  are made  comes care of the Trade Association of
       Rubber (NBR), NBR-HR (High-Resistance   In 2021, about  9% of Germany’s  ject of current research; probably some   the hub where they absorb forces, help  of silicon rubber or weather-resistant  the German Rubber Industry, wdk.
       NBR), Hydrogenated Nitrile Butadiene   total agricultural  land was used for  progress can be made by a smart combi-  minimize  vibrations and also  dampen  EPDM. However, the pivotal  sealing   ABOUT THE AUTHOR
       Rubber (HNBR) and even extremely   producing renewable raw materials for  nation  of gas-tight rubber grades and   noise.                       tasks are mostly performed by another   Dr. Stefan Albus is a Doctor of
       chemical-resistant fl uorelastomers – depen-  biogas production.    fi llers that obstruct hydrogen swelling                                      material.                          Chemistry and freelance trade jour-
       ding  on  the  temperature  profi le  and                           and permeation. Qualifying here as            Among the several hundreds of                                     nalist. His focal themes include
       aggressiveness of the fl ushing liquids.  Biogas, however, contains not only  basic elastomers  are butyl rubber –   kilos of elastomer materials  built into   Solar modules are often encapsu-  polymer chemistry as well as plastic
                                         the fuel that is methane but also corro-  already relatively gas-tight by defi nition –   wind  turbines,  you  will  hardly  fi nd  lated  in  ethylene-vinyl-acetate  fi lms   and rubber applications technology.
          Speaking of deep drilling: natural   sive ingredients such as hydrogen sul-  or  also  fl uor  rubber;  additives  with  a   any natural rubber, not least because  (EVA). In the process the solar modules

       166                                                                     Chemical Weekly  June 10, 2025        Chemical Weekly  June 10, 2025                                                                  167


                                      Contents    Index to Advertisers    Index to Products Advertised
   161   162   163   164   165   166   167   168   169   170   171