F-86

Keywords

material or part

Y1Z5

waterF34

manufacture of general-purpose machinery
Kurita Water Industries Ltd.

Technology for improving energy efficiency of heat exchangers
Features
What is Kurita Dropwise Technology?
S Primary applications
Improved heat transfer- Improved productivity & energy savings (CO2 emissions
reduction) are achieved via improvement to the heat transfer
coefficient of exchangers utilizing steam.
- The overall heat transfer coefficient (U value), an index
Improved productivity
representing the ease of heat transfer over the entire heatexchanger, is improved by up to 30% based on our testing.
S Highly versatile- The technology is effective on any condensation heat transfer
Energy saving
surfaces, regardless of type.
- The technology can be applied not only to new installations, butalso heat exchangers of existing installations.
- The technology is easily implemented, without mutuallyinterfering with the existing water treatment systems nor requiring modifications.
- Numerous implementations have been facilitated for water-steam cycle systems of medium to highpressure boilers that utilize steam turbines.
S How the technology is provided- The technology is provided as a package in chemicals, equipment and analyses.
- The technology can be provided by subsidiaries of Kurita Group, domestically and overseas.
S Decarbonization technology- The fuel consumption rate is improved by boosting energy efficiency.
Basic Concept or Summary
S Basic Concept
Heat exchangers using steam generated from boilers form a water film due to the condensate on the metal
surface on the steam side. This water film significantly reduces the heat transfer efficiency even if thethickness is minimal, and leads to an increase in the amount of steam, thereby consuming more energy andreducing productivity. The dropwise technology is a droplet condensation technology that enables water
repellency of metal surfaces on heat exchangers while eliminating the water film to improve the heat transfer
efficiency, boost productivity, and save energy via reduced steam consumption.
S Principle
Special chemicals mixed into the steam are absorbed onto the metal's surface in order to increase the water
repellency and transform the mode of condensation from the film to droplets. The heat transfer efficiency isimproved as the water film, which forms a thermal barrier, is removed. This technology, therefore, can beapplied while the production facility continues to operate without production downtime.
Heat

Steam

Heat

Steam

Chemical
Improvement ofwater repellency

Conventional process

Kurita Dropwise Technology

Not water repellent

Water repellent

Droplet condensation increases
heat transfer efficiency

Metal surface

Special chemicals produce
water repellency on metal surfaces

S Three steps for implementing our technology① Current conditions data analysis:
The current conditions of the target facility are diagnosed (narrowing down the facility type andverification of operating conditions)② Verification of the effectiveness for the target facility:
Technology implementation (operational adjustments for optimization, etc.)③ Full-scale adoption:
The level of improvements in energy efficiency diagnoses are conducted, with a relevant report submitted.

Effects or Remarks

E-86

Application periodof this technology
Steam consumption unit
[amount of steam/ production]

Overall heat transfer coefficient U (W/m2, K)

S Laboratory verification results
The laboratory verification results of this technology indicated an elevation of the U value as soon as theapplication of the technology began (first day) and the trend continued through to the ninth day. The U
value in this instance increased by 30%. A transition from the film condensation to the droplet
condensation was also visually observed on the heat exchanger surface as the U value increased.
S Examples of application on actual equipment
This is an example of the heat transfer efficiency in the dryer process at a paper mill, improved by applying
this technology, which led to a maximum improvement of steam consumption (amount of steam andproduction) by 8%. The improvement rate of steam consumption at the facilities that implemented thistechnology frequently reached 5% to 10%.

[Test conditions]
Shell: SUS ID 106mm, OD 114mm; Steam: 0.04 MPa
Tube: Cu ID 17 mm, oD 19 mm, L = 1500 mm, Cooling water RT, 1.2 m/sec

Time (days)

Laboratory verification result(Shell-and-tube type heat exchanger)

Steamconsumption
unit
significantlyimproved

Conventional means
This technology applied

Paper/printing paper
manufacturing
Steam consumption 180 tons/day

Manufactured products

Example of application on actual equipment(Drum dryer)

S The 2019 Energy Conservation Grand Prize (Product and Business Model Division) of the Agency of
Natural Resources and Energy Commissioner’s Award.
This technology is offered in packaged contracts that provide the technology to a multitude of users,
across all boundaries of industries.
Chemicals

Pay-perperformance fee

Equipment

Pay-perperformance fee

Analysis &analytical studies

Pay-perperformance fee

Product & Business Model Division Award
Installation in Practice or Schedule
Domestic• Drum dryers (dryer processes at paper mills, etc.), steam turbine condensers, reaction
kettles, etc.

Overseas• Drum dryers (dryer processes at paper mills, etc.), steam turbine condensers, reaction
kettles, press machines, etc.
• Since the market launch in 2017, this technology has been implemented at over 300
facilities around the world.
• This technology is supplied globally to water treatment chemical businesses in areas
specified in the figure below.

Source: https://www.kurita.co.jp/aboutus/gn_overseas.html

Contact:

Kurita Water Industries Ltd. (KCR Center)
Nakano Central Park East, 4-10-1 Nakano, Nakano-ku, Tokyo
Tel: +81-(0)120-40-7474
URL: https://www.kurita.co.jp/english/index.html