HKRITA’s Green Machine is Breakthrough that Recycling of Blended Textiles Needed, at Scale

The ITMF award that the Green Machine received in September is only the latest feather in its decorated cap. Developed by the Hong Kong Research Institute of Textiles and Apparel (HKRITA), the Green Machine has been making waves since its launch in 2016. Katherine Chan, Director (Business Development) at HKRITA, talks about the challenges that had to be encountered, and the excitement that the Green Machine has generated.

Long Story, Cut Short
  • The intention of the Green Machine is to develop a viable commercial solution to separate cotton and polyester blended textile. The first phase of the project started in 2016 and accomplished its lab scale development.
  • The whole process uses only heat, water and less than 15% of green chemical with a recovery rate of over 97% for polyester fibres in 2 hours.
  • In recycling textile waste of pure materials, there is no need to use the Green Machine.
The Green Machine is licensed by HKRITA at cost price, meaning it only covers their costs with no extra margins. For H&M Foundation and HKRITA this open-source approach is key to reach maximum impact and to transform the fashion industry.
Maximum Fibre The Green Machine is licensed by HKRITA at cost price, meaning it only covers their costs with no extra margins. For H&M Foundation and HKRITA this open-source approach is key to reach maximum impact and to transform the fashion industry. Hong Kong Research Institute of Textiles and Apparel

The Green Machine, developed by HKRITA with support from H&M Foundation, is the world’s first technology that can separate blended textiles at scale, without any quality loss.

In a nutshell:

  • The Green Machine is a polyester and cellulose recycling system by hydrothermal treatment and dissolution treatment on cotton and polyester blends.
  • Through decomposing cotton into cellulose powders, it enables the separation of the polyester fibres from the blends.
  • The separated fibres with no depolymerisation are ready for spinning and manufacturing of new fabric.
  • The cellulose powders, decomposed from the cotton, can be applied to functional products such as super-absorbency materials and regenerated cellulose fibres.
  • Through separation of the blended textile, the Green Machine recovers PET fibre for re-spinning, while converts cotton fibre into cellulosic powder for a number of uses, including the re-producing of cellulose composite fibre, cellulosic superabsorbent polymer for cotton farming (Absorboost), and PFC-free function durable water-repellent (DWR) surface finish, hence fulfilling the goal of “end-to-end recycling” where post-consumer textiles are recovered as the raw materials of the production cycle.
  • The whole process uses only heat, water and less than 15% of green chemical with a recovery rate of over 97% for polyester fibres in 2 hours.
  • Compared to the 67 GJ of energy needed for producing every ton of PET, the Green Machine uses only 19 GJ to produce the same amount of separated polyester fibres, saving 70% of total production energy used.

The Green Machine has, of course, found industry acceptance. Among those already using it are Monki, PT Kahanex and Isko.

Could you tell us how the project was conceptualised? What was the broad objective when HKRITA started working on the concept? How long did it take for the concept to take the final shape as a machine?
The intention of the Green Machine is to develop a viable commercial solution to separate cotton and polyester blended textile. The first phase of the project started in 2016 and accomplished its lab scale development. The second phase started in 2017 which developed a pre-industrial scale system to evaluate the parameters for scaling up to the treatment conditions to industrial scale. In 2020, we worked with a textile manufacturer to set up the first industrial scale Green Machine with a processing capacity of 1.5 tonnes per day in Indonesia. Optimisation of the Green Machine continues for better operation in industrial scale. We wold be only too glad to work with interested parties to adopt the technology in its production through the approach such as technology licensing. As a matter of fact, its first licencing agreement was made with a denim manufacturer in 2021.

What was the objective laid down by the H&M Foundation when it decided to support the Green Machine project? The Foundation website says that the programme period is for 2016–24. It's 2022. So, does it mean we are likely to see more developments on Green Machine?
The Planet First programme (2020–24) is a scale up from H&M Foundation’s previous collaboration with HKRITA, named Recycling Revolution (2016–19). It aims to find planet positive technologies that will not only focus on circularity and climate change, but also consider all aspects of earth’s natural support systems. This means not only minimising or eliminating the negative impact fashion can have on the planet but adding environmental benefits to the planet through the processes and actions taken in the value chain. We’ll definitely continue working on the Green Machine, but the portfolio of projects is big—it’s changing and developing and range from using textiles that can sequester CO2 to opening up a first of its kind open lab where innovators, researchers, suppliers and brands can meet, test new ideas and scale faster. The lab will be opened in Hong Kong during 2023.

The hydrothermal method of separating fibres was developed by engineers at Shinshu University. Would you describe this as the turning point in the project?
It is a joint development between HKRITA and Shinshu University. It was an important proof-of-concept or method development stage, when HKRITA and Shinshu University engineers conduct experiments to verify the feasibility of hydrothermal method in polyester-cotton blend separation. Then, the pre-industrial sized and the industrial sized systems are further developed by our researchers according to the method.

Mechanical recycling of blended fibres is getting discarded by and by. Where does the future lie: in hydrothermal processes like this, or out-and-out chemical recycling? Related question: Is HKRITA planning to refine this Green Machine, or would you call it a complete project altogether?
The material nature of textile wastes is complicated—some are blended and some are pure. Different approaches of textile waste recycling are taken into consideration to address the issue. The Green Machine focuses on the separation of cotton and polyester blended textiles and makes the two materials reusable again after separation. Optimisation and scaling of the Green Machine continues. For example, a PET decolouring process was added in the Green Machine in the Indonesia system. It is a physical decolouring process in which dye absorbent could be re-generated again, and no chemical bleaching is involved. The treated PET fibres will become pale in colour which can extend the application of the materials.

In recycling textile waste of pure materials, there is no need to use the Green Machine.

We are very upbeat about the prospect of the Green Machine. Currently, we are planning to build a new set of machine in Hong Kong for local recycling and demonstration purposes. We are studying the possibility to upscale the capacity. Lots of things are moving forward. Most importantly, the beauty of the Green Machine is that it is easy to adopt. It does not require a high engineering level of machinery. The investment cost is competitive.

Katherine Chan
Katherine Chan / Director (Business Development) / Hong Kong Research Institute of Textiles and Apparel

The quality of the polyester fibres is maintained after treatment by the Green Machine. Would you clarify that there is no difference in composition after the treatment? Could you please elaborate?
There is no depolymerisation of the polyester fibre during the hydrothermal separation and the strength of the fibre is maintained. As such the fibres are ready for re-spinning.

I believe the idea is to develop the Green Machine into a complete treatment process and an industrial set-up. How will the next phase be different from the current one? How is the current setup deployed? How much space does it require, and how difficult/easy is it to install the system? What is the cost for one such unit? Can it be used as a shared resource or is it just one license per one entity?
We are very upbeat about the prospect of the Green Machine. Currently, we are planning to build a new set of machine in Hong Kong for local recycling and demonstration purposes. We are studying the possibility to upscale the capacity. Lots of things are moving forward. Most importantly, the beauty of the Green Machine is that it is easy to adopt. It does not require a high engineering level of machinery. The investment cost is competitive. Energy consumption is not heavy. Interested parties around the globe can also license the Green Machine on non-exclusive base. The cost of a unit and operation model depend on the scale of the potential licensee intended to build and its business plan.

It's a hydrothermal process. So, there's usage of only heat and water. The website page says 19 GJ are required to produce the same amount of separated polyester fibres. That's about 5277KWH. Could you clarify? Also, how much water is needed for one cycle? What volume of fibres can be handled per cycle?
The figures are estimation per ton of PET output in hydrothermal separation. Water consumption and volume of fibres to be handled per cycle is a case-by-case issue depending on the system scale.

What is the feedback received from those who have used the Green Machine like for instance Monki, Isko, PT Kahatex. What has been the response to your licensing queries?
Both Isko and PT Kahatex are excited about this technology. A Swedish brand has already placed an order and it will be available on the market in the first quarter of 2023. This technology has got a wide range of interests globally. We are having an in-depth conversation with another brand. The second licensing agreement is about to reach soon.

A clarification. The H&M Foundation website says, "A small-scale pilot on cotton farming using the cellulose powder that is one of the outputs from the Green Machine is initiated in India." Could we have some details?
The hydrothermal separation process selectively decomposes cotton into cellulose powders, enabling the separation of the polyester fibres from the blends. The cellulose powders can be transformed into superabsorbent polymer (SAP) for agricultural application. We have carried out a small-scale pilot trial of using these SAPs in cotton farming in India in order to study the impact of SAP application in cotton farming, and to find out a suitable irrigation practice.

The Green Machine focuses on the separation of cotton and polyester blended textiles and makes the two materials reusable again after separation. Optimisation and scaling of the Green Machine continues. For example, a PET decolouring process was added in the Green Machine in the Indonesia system. It is a physical decolouring process in which dye absorbent could be re-generated again, and no chemical bleaching is involved. The treated PET fibres will become pale in colour which can extend the application of the materials.

Subir Ghosh

SUBIR GHOSH is a Kolkata-based independent journalist-writer-researcher who writes about environment, corruption, crony capitalism, conflict, wildlife, and cinema. He is the author of one book, and has co-authored three with others. He writes, edits, reports and designs. He is also a professionally trained and qualified photographer.

 
 
 
  • Dated posted: 17 October 2022
  • Last modified: 17 October 2022