Low-temperature drying of green tea lees for upcycling / Test cases / Green tea lees drying, Upcycling drying

summary

Introduction

KENKI DRYER is a steam dryer that performs indirect drying at low temperatures to achieve zero-emission drying while minimizing changes in the composition of green tea lees.

Current Status and Issues of Green Tea Lees

• Green tea lees are a byproduct of the green tea production process, with approximately 200,000 tons generated annually.
• If not properly processed, green tea lees decompose, emit a foul odor, and cause environmental problems.
• Green tea lees can be used as fertilizer, feed, fuel, soil conditioner, etc., but they are not fully utilized effectively.

Upcycle Green Tea Lees with KENKI DRYER

• KENKI DRYER dries green tea lees at low temperatures to reduce changes in composition and make them suitable for upcycling.
• Dried green tea lees can be used for various purposes such as fertilizer, feed, fuel, and soil conditioner.
• In particular, its use as an alternative fuel to wood and as biochar is attracting attention.

Features of KENKI DRYER

• Uniquely structured steam indirect dryer with 11 patented technologies from 8 countries around the world.
• Low-temperature drying reduces fuel cost, parts wear, and CO2 emissions.
• Continuous drying system allows easy operation control and 24-hour unmanned operation.
• Capable of drying sticky and tacky materials, and can handle difficult-to-dispose wastes.

Conclusion

The KENKI DRYER is a revolutionary drying system that promotes upcycling and recycling of green tea lees and contributes to solving environmental problems. If you are looking for a high water content organic waste dryer, sludge dryer, slurry dryer, methane fermentation digested liquid dryer, or waste recycling dryer, please consider KENKI DRYER.

Upcycling and recycling of organic waste such as green tea leaves is becoming increasingly important in terms of environmental protection and decarbonization.
KENKI DRYER uses steam from a boiler as a heat source for indirect low-temperature drying. Since it dries at low temperature, the composition of green tea leaves does not change much and can be effectively used as upcycling, thus enabling zero-emission drying.

Most of the tea produced in Japan is green tea. There are several types of green tea, including sencha, gyokuro, Kabusecha, Tencha, matcha, and Tamaryokucha. Tencha differs from matcha in that matcha is made by grinding Tencha into a fine powder in a tea mill. Gyokuro, Kabusecha, and Tencha are also called “Aoicha.
Consumption of green tea leaves has been declining, while consumption of green tea beverages has been increasing.
The annual expenditure per household on green tea (leaf tea) and tea beverages shows a decreasing trend for leaf tea and an increasing trend for tea beverages. The total amount is about 11,000 yen and has remained unchanged in recent years. Leaf tea is tea brewed from tea leaves, while green tea beverages are beverages made from green tea leaves, such as sencha, extracted or infused and packaged in a container.

When green tea lees are left in a high-moisture state, decomposition is caused by the activity of microorganisms (especially bacteria and mold) contained in the green tea lees. These microorganisms use the moisture and nutrients contained in the green tea lees to reproduce, producing gases and odors, and the growth of the microorganisms causes spoilage and the development of foul odors and pathogens. Drying is an effective way to solve these problems.

Green tea leaves are rich in nutrients such as nitrogen, phosphorus and potassium and are used as fertilizer, compost and soil conditioner for tea gardens and fields. It is also used as feed for livestock such as cattle and pigs.

Wood is currently in short supply in Japan. The use of beverage lees such as dried green tea leaves as fuel instead of wood, or the use of dried beverage lees as biochar by carbonization, is attracting a great deal of attention. For example, biochar is being used to replace coke in the steel and foundry industries.
Biochar is a carbonized material made from biological resources that is effective in revitalizing organisms and improving the environment. We can provide carbonization services using our Biogreen pyrolysis equipment, which uses no fossil fuels and does not emit CO2, a greenhouse gas, from the equipment.

KENKI DRYER, with 11 patents in 8 countries, is an indirect steam dryer, but it is a completely unique product, different in structure from other similar indirect steam dryers. The KENKI DEYER uses steam as a heat source, but its high drying heat efficiency means that less steam is used. The use of excess steam is not costly in terms of fuel costs, and the dryer does not emit carbon dioxide during the drying process, allowing for decarbonized drying. Alternatively, by installing an electric boiler, no greenhouse gases or CO2 emissions are generated during drying.
The KENKI DRYER is a continuous dryer, not a batch dryer that stores and dries materials to be dried. Therefore, operation is simple and unmanned operation is possible 24 hours a day.

Drying green tea lees to reduce their weight and the amount of waste materials can contribute to environmental protection and decarbonization by reducing the cost of industrial waste, which is increasing due to the recent trucking problem in 2024, and by reducing the number of trucks used to transport waste.

KENKI DRYER, which can dry sticky and adhesive materials that cannot be dried anywhere else, is an epoch-making dryer with a total of 11 patents (2 in Japan and 9 in 7 foreign countries). Please consider KENKI DRYER for your high moisture content organic waste dryer, sludge dryer, slurry dryer, methane fermentation digested liquid dryer, and waste recycling dryer.

Green tea is a type of tea that is made from Camellia sinensis leaves and buds that have not undergone the same withering and oxidation process which is used to make oolong teas and black teas. Green tea originated in China, and since then its production and manufacture has spread to other countries in East Asia.
Several varieties of green tea exist, which differ substantially based on the variety of C. sinensis used, growing conditions, horticultural methods, production processing, and time of harvest.

Source：Wiki Green tea

“Japanese tea” is the term used in daily conversation and refers to ‘tea of Japan,’ that is, ‘tea made in Japan’ or ‘a kind of tea which is often drunk in Japan.’
It is not a term defined as tea in a scholarly classification.

Variety of Japanese tea

Many types Japanese tea are made through a process of heat-treating by steaming to prevent oxidization and fermentation, crumpled (some tea is not crumpled) and dried. Tea leaves stop fermenting immediately when they are heat-treated soon after being picked. Therefore, Japanese tea usually means green tea. Some Japanese tea is heat-treated by roasting in an iron pot instead of steaming. Japanese tea processed like this is called “Kamairicha.” Ureshino-cha in Kyushu (southernmost of the four main islands of Japan) is one of the famous Kamairicha. The process of steaming is seen only in Japan and the process of roasting is similar to that done with Chinese tea.

The term ‘Sencha’ (green tea) is often used both in a narrow sense and in a broad sense. ‘Sencha’ in the narrow sense refers to middle class green tea between Gyokuro (refined green tea) (high-quality tea) and Bancha (coarse tea) (low-quality tea) (in detail, see Gyokuro, Sencha, and Bancha). ‘Sencha’ in a broad sense, is a term for the tea that is not made into powder, and which was transmitted from China since recent times, as opposed to Macha (the powdered green tea used for ceremonies) (steamed and dried before being stone-ground) which was established before medieval times.

Green tea is almost synonymous with unfermented tea (不発酵茶) in scholarly classification, but in Japan it generally means Sencha (in a broad sense) simply, the green tea which is produced most often. In other words, it means Gyokuro, Bancha, Hojicha (roasted green tea), Genmaicha (tea with roasted rice) and so on, other than Sencha (in a narrow sense). Moreover, in a broader sense, Macha is also included.

In some parts of Japan, a fermented tea which is similar to the black tea of China, is produced and called Tsukemono-cha (漬物茶). It is produced mainly in the Shikoku region, such as Awa-bancha in Tokushima Prefecture, Goishi-cha in Kochi Prefecture and Ishizuchikuro-cha in Ehime Prefecture. Batabata-cha in Toyama Prefecture is also included in areas other than Shikoku region.

Source：Japanese Wiki Corpus Japanese tea

Drying green tea lees, which are the leftover materials after the tea leaves have been brewed, serves several purposes:

1. Preservation: Drying helps in preserving the green tea lees for a longer period. Moisture can lead to mold and spoilage, so reducing the water content extends shelf life.
2. Storage: Dried green tea lees take up less space compared to their wet counterparts, making them easier to store and handle.
3. Flavor Concentration: Drying can concentrate the flavors, making the lees more potent when reused in recipes or as flavoring agents.
4. Versatility: Dried green tea lees can be used in a variety of ways, such as in cooking, baking, or as a seasoning. They can also be ground into a powder and used in teas, smoothies, or other beverages.
5. Nutrient Retention: Proper drying methods help retain the nutritional content of the lees, including antioxidants, vitamins, and minerals, which can be beneficial when they are repurposed.
6. Commercial Use: Dried green tea lees can be processed and sold as a product for culinary or health purposes, adding value to what would otherwise be waste.
7. Environmental Impact: By drying and repurposing green tea lees, waste is reduced, contributing to more sustainable practices.
8. Ease of Use: Dried green tea lees are easier to grind into a fine powder, which can be used in various applications, from food products to cosmetics.

Drying methods can vary, including sun drying, oven drying, and using dehydrators, each with its own impact on the final quality of the dried lees.

Source：ChatGPT

• Material to be dry: Green tea lees
• Purpose of drying: Upcycling, Reducing industrial waste cost and amount
• Moisture content: 70.2％W.B. before drying, 4.9％W.B. after drying
• Requirements for dryer: To prevent clogging inside the dryer caused by the stickiness and adhesiveness. Automated continuous operation with no operator attended.
  Machine cost can be recovered in short term.
• Test result: OK

Waste drying

Competitive comparison

A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but has since also been applied to other sources of heat energy, such as nuclear energy (via nuclear fission and nuclear fusion).
The heat energy released by reactions of fuels can be converted into mechanical energy via a heat engine. Other times, the heat itself is valued for warmth, cooking, or industrial processes, as well as the illumination that accompanies combustion. Fuels are also used in the cells of organisms in a process known as cellular respiration, where organic molecules are oxidized to release usable energy. Hydrocarbons and related organic molecules are by far the most common source of fuel used by humans, but other substances, including radioactive metals, are also utilized.
Fuels are contrasted with other substances or devices storing potential energy, such as those that directly release electrical energy (such as batteries and capacitors) or mechanical energy (such as flywheels, springs, compressed air, or water in a reservoir).

Source：Wiki Fuel

Compost is a mixture of ingredients used as plant fertilizer and to improve soil’s physical, chemical, and biological properties. It is commonly prepared by decomposing plant and food waste, recycling organic materials, and manure. The resulting mixture is rich in plant nutrients and beneficial organisms, such as bacteria, protozoa, nematodes, and fungi. Compost improves soil fertility in gardens, landscaping, horticulture, urban agriculture, and organic farming, reducing dependency on commercial chemical fertilizers. The benefits of compost include providing nutrients to crops as fertilizer, acting as a soil conditioner, increasing the humus or humic acid contents of the soil, and introducing beneficial microbes that help to suppress pathogens in the soil and reduce soil-borne diseases.

Source：Wiki Compost

A fertilizer (American English) or fertiliser (British English) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Many sources of fertilizer exist, both natural and industrially produced. For most modern agricultural practices, fertilization focuses on three main macro nutrients: nitrogen (N), phosphorus (P), and potassium (K) with occasional addition of supplements like rock flour for micronutrients. Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment or hand-tool methods.

Source：Wiki Fertilizer

The three primary elements of fertilizer, essential for plant growth and commonly referred to as macronutrients in the context of plant nutrition, are:

Nitrogen (N):
Function: Promotes leaf and stem growth, as it is a crucial component of chlorophyll, the compound that plants use in photosynthesis to convert sunlight into energy. Nitrogen is also a key part of amino acids, the building blocks of proteins.
Deficiency Symptoms: Yellowing of leaves (chlorosis), stunted growth, and poor yield.

Phosphorus (P):
Function: Essential for energy transfer and storage in plants, as it is a component of ATP (adenosine triphosphate). Phosphorus also plays a vital role in root development, flowering, and seed production.
Deficiency Symptoms: Dark green or purplish leaves, delayed maturity, and poor root development.

Potassium (K):
Function: Regulates various metabolic activities in plants, including photosynthesis, protein synthesis, and water regulation. Potassium is also important for improving disease resistance and overall plant health.
Deficiency Symptoms: Leaf edges may turn yellow or brown (scorching), weak stems, and reduced resistance to drought and diseases.
Fertilizers are often labeled with an N-P-K ratio, which indicates the relative proportions of these three essential nutrients. For example, a fertilizer labeled as 10-20-10 contains 10% nitrogen, 20% phosphorus, and 10% potassium.

Source：ChatGPT

The shortage of lumber in Japan as of 2024 can be attributed to several factors:

1. Increased Demand: The global demand for lumber has surged due to a post-pandemic construction boom. As economies recover, the need for housing, infrastructure, and renovations has significantly increased, putting pressure on lumber supplies.

2. Supply Chain Disruptions: Ongoing disruptions in global supply chains, including transportation delays, port congestions, and logistical challenges, have made it difficult to import lumber into Japan efficiently.

3. Reduced Domestic Production: Japan’s domestic lumber production has been declining due to factors such as aging forestry workers, a lack of investment in modern forestry practices, and environmental regulations that limit logging activities.

4. Natural Disasters: Japan is prone to natural disasters such as earthquakes, typhoons, and floods, which can disrupt lumber production and supply chains, further exacerbating shortages.

5. Environmental Regulations: Stricter environmental regulations and sustainability practices have led to reduced logging activities in Japan and other countries, limiting the availability of lumber.

6. Geopolitical Tensions: Trade tensions and geopolitical issues with major lumber-producing countries can impact the availability and cost of imported lumber. Restrictions or tariffs on lumber exports from key suppliers can lead to shortages.

7. Economic Factors: Fluctuations in currency exchange rates, inflation, and the overall economic climate can affect the affordability and accessibility of imported lumber.

8. COVID-19 Impact: The lingering effects of the COVID-19 pandemic, including labor shortages and health-related restrictions, continue to impact production and transportation sectors globally, affecting lumber supply.

9. Forest Management Issues: Poor forest management practices and insufficient reforestation efforts in Japan have led to a depletion of local timber resources, contributing to the shortage.

These factors combined create a challenging environment for ensuring a steady supply of lumber in Japan, impacting various sectors that rely on this essential resource.

Source：ChatGPT

Biochar is a form of charcoal that is produced by heating organic material (biomass) such as wood, crop residues, or manure in a controlled environment with little or no oxygen through a process called pyrolysis. Here are some key aspects of biochar:

1. Production Process: Biochar is created through pyrolysis, which involves heating biomass in the absence of oxygen. This process thermally decomposes the organic material, producing a stable, carbon-rich product.

2. Soil Amendment: One of the primary uses of biochar is as a soil amendment. When added to soil, it can enhance soil fertility, improve water retention, increase microbial activity, and reduce the need for chemical fertilizers.

3. Carbon Sequestration: Biochar is highly stable and can remain in the soil for hundreds to thousands of years, effectively sequestering carbon and reducing greenhouse gas emissions. This makes it a valuable tool in mitigating climate change.

4. Environmental Benefits: Biochar can help reduce soil erosion, improve soil structure, and increase agricultural productivity. It also has the potential to filter and remove contaminants from soil and water, contributing to environmental remediation.

5. Energy Production: The pyrolysis process that produces biochar also generates syngas (a mixture of hydrogen, carbon monoxide, and other gases) and bio-oil, which can be used as renewable energy sources.

6. Waste Management: By converting agricultural and forestry residues, animal manure, and other organic waste into biochar, it provides a sustainable method of managing waste materials.

7. Livestock and Composting: Biochar can be used in animal husbandry to improve feed efficiency and reduce methane emissions from livestock. It is also used in composting to enhance the composting process and reduce odors.

8. Water Purification: Due to its porous structure and high surface area, biochar can be used as a filtration medium to remove pollutants from water, including heavy metals, organic contaminants, and nutrients.

Overall, biochar represents a versatile and sustainable solution with multiple applications in agriculture, environmental management, and energy production, contributing to both soil health and climate change mitigation.

Source：ChatGPT

Uses of Biochar from Beverage Lees

1. Soil Amendment:
   • Improving Soil Fertility: Biochar enhances soil fertility by increasing nutrient retention and improving soil structure.
   • Water Retention: Its porous structure helps retain moisture in the soil, reducing the need for frequent watering.
   • Microbial Activity: Biochar provides a habitat for beneficial soil microorganisms, enhancing soil health and plant growth.
2. Environmental Applications:
   • Carbon Sequestration: Biochar is stable and can sequester carbon for hundreds to thousands of years, helping mitigate climate change.
   • Pollution Remediation: Biochar can adsorb heavy metals and organic pollutants, making it useful for soil and water remediation efforts.
3. Agricultural Uses:
   • Compost Enhancer: Adding biochar to compost can improve the composting process and enhance the nutrient content of the final product.
   • Animal Bedding: Biochar can be used as animal bedding to reduce odors and improve waste management.
4. Industrial Applications:
   • Filtration: Due to its high surface area and adsorptive properties, biochar can be used in water filtration systems.
   • Energy Production: The by-products of the pyrolysis process, such as syngas and bio-oil, can be used as renewable energy sources.
5. Horticulture:
   • Gardening: Biochar can be mixed with potting soil to improve plant growth and reduce the frequency of watering and fertilizing.
   • Greenhouse Media: It can be used as a growing medium in greenhouses, enhancing plant health and productivity.

Source：ChatGPT

Using biochar as a coke substitute in metallurgical processes, particularly in iron and steel production, is an emerging concept aimed at reducing the environmental impact of traditional coke usage. Here’s a detailed look at the potential of biochar as a coke substitute:

Background on Coke in Metallurgy

1. Role of Coke: Coke is used as both a fuel and a reducing agent in blast furnaces. It provides the high temperatures necessary for melting iron ore and the carbon required to reduce iron oxides to metallic iron.
2. Environmental Concerns: The production and use of coke result in significant carbon dioxide (CO₂) emissions and other pollutants.

Biochar as a Coke Substitute

1. Production of Biochar: Biochar is produced through the pyrolysis of organic materials (biomass) in a low-oxygen environment. Common feedstocks include agricultural residues, wood chips, and other organic waste.
2. Properties: Biochar is rich in carbon, highly porous, and has a high surface area. These properties make it potentially useful in metallurgical processes.

Advantages of Using Biochar

1. Reduced Emissions: Biochar is considered carbon-neutral or even carbon-negative, as it can sequester carbon that would otherwise be released into the atmosphere.
2. Renewable Resource: Unlike coke, which is derived from coal, biochar comes from renewable biomass sources, making it more sustainable.
3. Waste Utilization: Producing biochar from agricultural and forestry waste materials adds value to these by-products and reduces waste.

Challenges

1. Consistency and Quality: The properties of biochar can vary depending on the feedstock and production conditions, which may affect its performance as a coke substitute.
2. Economic Feasibility: Producing biochar at the scale needed for industrial metallurgy can be expensive, and the economic viability needs to be assessed.
3. Technical Compatibility: Existing blast furnaces and metallurgical processes are optimized for coke. Adapting them to use biochar may require significant modifications.

Research and Development

1. Optimizing Production: Research is ongoing to optimize the production of biochar for metallurgical use, focusing on achieving the desired carbon content and physical properties.
2. Pilot Projects: Pilot projects and studies are being conducted to test the feasibility of using biochar in industrial settings, such as in steel mills.
3. Lifecycle Analysis: Comprehensive lifecycle analyses are being performed to evaluate the environmental and economic impacts of substituting coke with biochar.

Potential Applications

1. Iron and Steel Production: Biochar can be used as a reducing agent and fuel in blast furnaces and electric arc furnaces, potentially reducing the carbon footprint of steel production.
2. Non-Ferrous Metallurgy: Biochar could be used in the production of non-ferrous metals, where reducing agents are required.
3. Other High-Temperature Processes: Biochar can be employed in various industrial processes that require high temperatures and reducing environments.

Conclusion

Using biochar as a coke substitute in metallurgical processes offers promising environmental benefits, particularly in reducing greenhouse gas emissions and utilizing renewable resources. However, several challenges need to be addressed, including ensuring consistent quality, economic feasibility, and compatibility with existing industrial processes. Continued research and development, along with pilot projects, will be crucial in determining the practicality and scalability of biochar as a coke substitute in the metallurgy industry.

Source：ChatGPT

One of the International Patented Technology that KENKI DRYER has is a self-cleaning structure called Steam Heated Twin Screw technology (SHTS technology). No matter how materials are sticky, adhesive and viscous is, they can be dried without clogging inside of the dryer because of this unique structure that no other products has.
For example, even materials stuck to the blades of one screw, blades of the other screw in the dryer’s body forcibly peels the materials off as they rotate. Since the blades rotate by peeling the material off each other, any sticky, adhesive and viscous material does not adhere to the blade, and the blades continue rotating, peeling, agitating and heating material without stopping while they carries material further. Also, since surface of blades are always renewed and kept clean, heat near the blades is not blocked and it is conducted directly into the materials.

Self-cleaning screw

KENKI DRYER has three main characteristics. They are 1) Any materials can be dried as expected including sticky, adhesive and viscous materials and raw material slurry that no other company can deal with, 2) dried material can by recycled or utilized as raw materials because of its low-temperature drying method, and 3) there is no need to assign operator since its continuous operating system makes 24 hours unattended operation possible.

Products

The unique and original drying mechanism of KENKI DRYER is also International Patented Technology. Because 4 drying mechanisms which are crashing drying, agitation drying, circulation drying and indirect drying work simultaneously and add heat to material being dried repeatedly and continuously, inner part of the material is dried thoroughly and quality of discharged material after drying is stable. This series of drying mechanisms prevents agglomeration which causes insufficient drying from feeding process of the material into the dryer until discharging process after drying completed. Various ingenuities to conduct heat surely into inner part of the materials are exercised and stable heating and drying are proceeded continuously.

Methods

Even KENKI DRYER uses only saturated steam as its heat source, it is outstanding in safety and hygiene point of view with its unique drying mechanism based on combined use of conductive heat transfer method and heated air method. Since steam is a stable heat source, quality of discharged material after drying is also stable and equable. Maximum allowed steam pressure is 0.7Mpa and adjustment of steam pressure, adjustment of drying temperature in other words, can be easily done. Saturated steam is commonly used in many factories so that it can be said as a familiar and handy heat source. In comparison with drying methods using burner or hot blasts, saturated steam method is an indirect drying applying heat exchange via pipes that steam is passing through, therefore, it hardly burns the materials and is outstanding in safety and hygiene point of view.

Heat source, Steam