工業用浄化熱回収

産業廃熱回収・浄化ソリューションの総合サービスプロバイダー

著者アーカイブ シャオハイ

  • 家 /
  • 投稿者による記事 シャオハイ
    • ( ページ3 ) ( ページ3 )

NMP熱回収における空気対空気熱交換器の仕組み

An air-to-air heat exchanger in NMP heat recovery transfers thermal energy between a hot, NMP-laden exhaust air stream from an industrial process and a cooler incoming fresh air stream, improving energy efficiency in industries like battery manufacturing.

The hot exhaust air (e.g., 80–160°C) and cooler fresh air pass through separate channels or over a heat-conductive surface (e.g., plates, tubes, or a rotary wheel) without mixing. Heat transfers from the hot exhaust to the cooler fresh air via sensible heat transfer. Common types include plate heat exchangers, rotary heat exchangers, and heat pipe heat exchangers.

NMP-specific designs use corrosion-resistant materials like stainless steel or glass fiber-reinforced plastic to withstand NMP’s aggressive nature. Larger fin spacing or clean-in-place systems prevent fouling from dust or residues. Condensation is managed to avoid blockages or corrosion.

The hot exhaust air transfers heat to the fresh air, preheating it (e.g., from 20°C to 60–80°C) and reducing energy needs for subsequent processes. The cooled exhaust air (e.g., 30–50°C) is sent to an NMP recovery system (e.g., condensation or adsorption) to capture and recycle the solvent. Heat recovery efficiency is 60–95%, depending on the design.

This reduces energy consumption by 15–30%, lowers greenhouse gas emissions, and improves NMP recovery by cooling the exhaust air for easier solvent capture. Challenges like fouling are addressed with wider gaps, extractable elements, or cleaning systems, while robust sealing prevents cross-contamination.

In a battery manufacturing plant, a plate heat exchanger preheats fresh air from 20°C to 90°C using 120°C exhaust air, reducing oven energy demand by ~70%. The cooled exhaust air is processed to recover 95% of NMP.

木材乾燥における空気対空気熱交換器の仕組み

An air-to-air heat exchanger in wood drying transfers heat between two air streams without mixing them, optimizing energy efficiency and controlling drying conditions. Here's how it works:

  1. Purpose in Wood Drying: Wood drying (kiln drying) requires precise temperature and humidity control to remove moisture from wood without causing defects like cracking or warping. The heat exchanger recovers heat from exhaust air (leaving the kiln) and transfers it to incoming fresh air, reducing energy costs and maintaining consistent drying conditions.
  2. Components:
    • A heat exchanger unit, typically with a series of metal plates, tubes, or fins.
    • Two separate air pathways: one for hot, humid exhaust air from the kiln and one for cooler, fresh incoming air.
    • Fans or blowers to move air through the system.
  3. Working Mechanism:
    • 排気: Hot, moisture-laden air from the kiln (e.g., 50–80°C) passes through one side of the heat exchanger. This air carries heat energy from the drying process.
    • 熱伝達: The heat from the exhaust air is conducted through the exchanger’s thin metal walls to the cooler incoming fresh air (e.g., 20–30°C) on the other side. The metal ensures efficient heat transfer without mixing the two air streams.
    • Fresh Air Heating: The incoming air absorbs the heat, raising its temperature before it enters the kiln. This preheated air reduces the energy needed to heat the kiln to the desired drying temperature.
    • Moisture Separation: The exhaust air, now cooler, may condense some of its moisture, which can be drained away, helping to control humidity in the kiln.
  4. Types of Heat Exchangers:
    • プレート式熱交換器: Use flat plates to separate air streams, offering high efficiency.
    • Tube Heat Exchangers: Use tubes for air flow, durable for high-temperature applications.
    • Heat Pipe Exchangers: Use sealed pipes with a working fluid to transfer heat, effective for large kilns.
  5. Benefits in Wood Drying:
    • エネルギー効率: Recovers 50–80% of heat from exhaust air, lowering fuel or electricity costs.
    • Consistent Drying: Preheated air maintains stable kiln temperatures, improving wood quality.
    • 環境への影響: Reduces energy consumption and emissions.
  6. 課題:
    • メンテナンス: Dust or resin from wood can accumulate on exchanger surfaces, requiring regular cleaning.
    • 初期費用: Installation can be expensive, though offset by long-term energy savings.
    • Humidity Control: The system must balance heat recovery with proper moisture removal to avoid overly humid conditions.

In summary, an air-to-air heat exchanger in wood drying captures heat from exhaust air to preheat incoming air, improving energy efficiency and maintaining optimal drying conditions. It’s a critical component in modern kiln systems for sustainable, high-quality wood processing.

外気システムにおける空気対空気熱交換器の仕組み

外気システムにおける空気対空気熱交換器は、流入する新鮮な空気と排出される古い空気の間で熱を伝達しますが、両者を混合することはありません。その仕組みは以下のとおりです。

  1. 構造熱交換器は、薄いチャネルまたはプレートが交互に配置されたコアで構成されており、多くの場合金属またはプラスチック製で、入ってくる空気と出ていく空気を分離します。これらのチャネルは、空気の流れを遮断しながら熱伝達を可能にします。
  2. 熱伝達:
    • 冬には、排気される暖かい室内の空気がその熱をより冷たい新鮮な空気に伝え、それを暖めます。
    • 夏には、涼しい室内の空気がその「涼しさ」を暖かい空気に移し、暖かい空気を事前に冷却します。
    • このプロセスは、温度差によって熱交換器の壁を介した伝導によって発生します。
  3. 種類:
    • クロスフロー: 空気の流れが垂直に流れるため、中程度の効率が得られます(50-70%)。
    • 逆流: 空気の流れが反対方向に流れ、熱伝達が最大化されます (最大 90% の効率)。
    • ロータリー（エンタルピーホイール）回転ホイールが熱と湿気を吸収・移動し、湿度コントロールに最適です。
  4. 利点:
    • 排気熱の50～90%を回収することでエネルギーロスを削減します。
    • 冷暖房コストを最小限に抑えながら新鮮な空気を供給することで、室内の空気の質を維持します。
  5. 外気システムでの操作:
    • ファンが交換器を通じて建物から古い空気を吸い込み、別のファンが新鮮な屋外の空気を吸い込みます。
    • 交換器により、流入する空気が分配前に（室内温度に近くなるように）調整され、HVAC システムの負荷が軽減されます。
  6. 湿気コントロール （一部のモデル）
    • エンタルピー交換器は湿気も移動させ、室内の過度の乾燥や湿気を防ぎます。

このシステムは、空気の質を維持しながら熱をリサイクルすることで、換気効率、エネルギー節約、快適性を確保します。

空気対空気熱交換器はどのように機能するのか

空気対空気熱交換器は、2つの別々の空気流を混合することなく、熱を伝達します。通常、アルミニウムなどの熱伝導性材料で作られた薄い板またはチューブを、表面積が最大になるように配置して構成されています。一方の空気流（例：建物からの暖かい排気）は片側を流れ、もう一方の空気流（例：冷たい新鮮な空気）は反対側を流れます。

暖かい空気流の熱は伝導性材料を通過して冷たい空気流へと伝わり、空気流を温めます。このプロセスにより、本来失われるはずだったエネルギーが回収され、暖房または冷房システムの効率が向上します。クロスフロー式やカウンターフロー式の熱交換器などの設計では、空気を特定のパターンに導くことで熱伝達を最適化します。効率は空気流量、温度差、熱交換器の設計などの要因によって異なりますが、通常は50～80%の熱を回収します。

一部のモデル（例：エンタルピー交換器）では、特殊な膜を用いて水蒸気と熱を移動させ、湿度制御に役立てることで、水分移動が発生する場合があります。このシステムでは、空気を移動させるためのファンが必要であり、メンテナンスには詰まりや汚染を防ぐための清掃が必要です。

how does a heat exchanger work in a boiler

A heat exchanger in a boiler transfers heat from the combustion gases to the water circulating in the system. Here's how it works step by step:

  1. Combustion occurs: The boiler burns a fuel source (like natural gas, oil, or electricity), creating hot combustion gases.

  2. Heat transfer to the heat exchanger: These hot gases flow through a heat exchanger—typically a coiled or finned metal tube or series of plates made of steel, copper, or aluminum.

  3. Water circulation: Cold water from the central heating system is pumped through the heat exchanger.

  4. Heat absorption: As the hot gases pass over the surfaces of the heat exchanger, heat is conducted through the metal into the water inside.

  5. Hot water delivery: The now-heated water is circulated through radiators or to hot water taps, depending on the boiler type (combi or system boiler).

  6. Gas expulsion: The cooled combustion gases are vented out through a flue.

In condensing boilers, there's an extra stage:

  • After the initial heat transfer, the remaining heat in the exhaust gases is used to preheat incoming cold water, extracting even more energy and improving efficiency. This process often creates condensate (water), which is drained from the boiler.

industrial air to air heat exchanger | counterflow heat exchanger

工業用空気対空気熱交換器 | 向流熱交換器

アン 産業用空気対空気熱交換器 2つの空気流を混合することなく熱を伝達し、HVACシステム、産業プロセス、換気におけるエネルギー効率を向上させます。 向流熱交換器 2 つの空気流が反対方向に流れ、交換面全体で一貫した温度勾配により熱伝達効率が最大化される特殊なタイプです。

産業用空気対空気向流熱交換器の主な特徴:

  • 効率: 向流設計では、高温流と低温流の温度差が比較的一定に保たれるため、直交流熱交換器や並流熱交換器に比べて、より高い熱効率 (多くの場合 70-90%) が達成されます。
  • 工事耐久性と耐腐食性を高めるため、通常はアルミニウム、ステンレス鋼、ポリマーなどの材料で作られています。プレート型またはチューブ型が一般的です。
  • アプリケーション: 工業用乾燥、廃熱回収、データ センター、建物の換気で空気を予熱または予冷するために使用されます。
  • 利点: エネルギーコストを削減し、二酸化炭素排出量を減らし、相互汚染を防ぐことで空気の質を維持します。
  • 課題: 逆流設計のため圧力損失が高く、ファンの消費電力が増加する場合があります。汚れや詰まりを防ぐため、メンテナンスが必要です。

例：

工場では、向流熱交換器によって高温の排気（例：80°C）から熱を回収し、流入する新鮮な空気（例：10°C ～ 60°C）を予熱することで、加熱エネルギーを大幅に節約できます。

industrial air to air heat exchanger | counterflow heat exchanger

工業用空気対空気熱交換器 | 向流熱交換器

熱交換器は湿気を除去しますか?

標準的な空気対空気熱交換器は、主に2つの気流間で熱を伝達し、湿気を直接除去することはありません。2つの気流は分離されているため、一方の気流に含まれる水分（湿度）は通常、その気流内に留まります。ただし、熱交換器の種類によって微妙な違いがあります。

  1. 顕熱交換器これら（例えば、ほとんどのプレート式熱交換器やヒートパイプ式熱交換器）は熱のみを伝達し、水分は伝達しません。吸気と排気の湿度レベルは変化しませんが、温度変化によって相対湿度がわずかに変化することがあります（暖かい空気はより多くの水分を保持できるため、吸気を温めると相対湿度が低下する可能性があります）。
  2. エンタルピー（総エネルギー）交換器ロータリーホイールや特定の膜式熱交換器などの高度な設計では、熱と湿気の両方を移動させることができます。これらは吸湿性換気装置またはエンタルピー回収換気装置（ERV）と呼ばれます。コア材またはホイールが湿った空気流（例：暖かく湿った室内空気）から水分を吸収し、乾燥した空気流（例：冷たく乾燥した屋外空気）へと移動させることで、湿度をある程度効果的に管理します。
  3. 結露の影響特定の条件下では、熱交換器が湿った空気を露点以下に冷却すると、熱交換器の表面に結露が発生し、空気流から水分が除去されることがあります。これは付随的な現象であり、主要な機能ではありません。そのため、排水システムが必要となります。

したがって、標準的な熱交換器は、水分移動用に設計されたエンタルピー型ERVでない限り、または結露が発生しない限り、湿気を除去することはできません。湿度制御が目的の場合は、ERVまたは別途除湿システムが必要になります。

熱回収ホイールエアハンドリングユニット

A heat recovery wheel in an air handling unit (AHU) is a device that improves energy efficiency by transferring heat and sometimes moisture between incoming fresh air and outgoing exhaust air. Here's a concise explanation:

How It Works

  • 構造: The heat recovery wheel, also called a rotary heat exchanger, thermal wheel, or enthalpy wheel, is a rotating cylindrical matrix typically made of aluminum or a polymer, often coated with a desiccant (e.g., silica gel) for moisture transfer. It has a honeycomb structure to maximize surface area.

  • Operation: Positioned between the supply and exhaust air streams in an AHU, the wheel rotates slowly (10-20 RPM). As it turns, it captures heat from the warmer air stream (e.g., exhaust air in winter) and transfers it to the cooler air stream (e.g., incoming fresh air). In summer, it can pre-cool incoming air.

  • 種類:

    • Sensible Heat Wheel: Transfers only heat, affecting air temperature without changing moisture content.

    • Enthalpy Wheel: Transfers both heat (sensible) and moisture (latent), using a desiccant to adsorb and release water vapor based on humidity differences. This is more effective for total energy recovery.

  • 効率: Sensible heat recovery can achieve up to 85% efficiency, while enthalpy wheels may add 10-15% more by recovering latent heat.

利点

  • エネルギー節約: Pre-conditions incoming air, reducing heating or cooling loads, especially in climates with large indoor-outdoor temperature differences.

  • Improved Air Quality: Supplies fresh air while recovering energy from exhaust air, maintaining indoor comfort.

  • アプリケーション: Common in commercial buildings, hospitals, schools, and gyms where high ventilation rates are needed.

Key Considerations

  • メンテナンス: Regular cleaning is critical to prevent dirt or clogs from reducing efficiency. Filters should be replaced, and the wheel inspected for buildup.

  • Leakage: Slight cross-contamination between air streams is possible (Exhaust Air Transit Ratio <1% in well-maintained systems). Overpressure on the supply side minimizes this risk.

  • Frost Prevention: In cold climates, wheel frosting can occur. Systems use variable speed control (via VFD), preheating, or stop/jogging to prevent this.

  • Bypass Dampers: Allow the wheel to be bypassed when heat recovery isn’t needed (e.g., during mild weather), saving fan energy and extending wheel life.

Example

In a hospital AHU, a heat recovery wheel might pre-heat incoming winter air (e.g., from 0°C to 15°C) using exhaust air (e.g., 24°C), reducing the heating system’s workload. In summer, it could pre-cool incoming air (e.g., from 35°C to 25°C) using cooler exhaust air.

Limitations

  • Space: Wheels are large, often the biggest AHU component, requiring careful installation planning.

  • Cross-Contamination: Not ideal for applications requiring complete air stream separation (e.g., labs), though modern designs minimize this.

  • Cost: Initial cost is high, but energy savings often justify it in high-ventilation settings.

how does a cross flow heat exchanger work

A crossflow heat exchanger works by allowing two fluids to flow at right angles (perpendicular) to each other, typically with one fluid flowing through tubes and the other flowing across the outside of the tubes. The key principle is that heat is transferred from one fluid to the other through the walls of the tubes. Here's a step-by-step breakdown of how it works:

Components:

  1. Tube Side: One of the fluids flows through the tubes.

  2. Shell Side: The other fluid flows over the tubes, across the tube bundle, in a direction perpendicular to the flow of the fluid inside the tubes.

Working Process:

  1. Fluid Inlet: Both fluids (hot and cold) enter the heat exchanger at different inlets. One fluid (let's say the hot fluid) enters through the tubes, and the other fluid (cold fluid) enters the space outside the tubes.

  2. Fluid Flow:

    • The fluid flowing inside the tubes moves in a straight or slightly twisted path.

    • The fluid flowing outside the tubes crosses over them in a perpendicular direction. The path of this fluid can be either crossflow (directly across the tubes) or have a more complex configuration, like a combination of crossflow and counterflow.

  3. 熱伝達:

    • Heat from the hot fluid is transferred to the tube walls and then to the cold fluid flowing across the tubes.

    • The efficiency of heat transfer depends on the temperature difference between the two fluids. The larger the temperature difference, the more efficient the heat transfer.

  4. Outlet: After heat transfer, the now cooler hot fluid exits through one outlet, and the now warmer cold fluid exits through another outlet. The heat exchange process results in a temperature change in both fluids as they flow through the heat exchanger.

Design Variations:

  • Single-pass crossflow: One fluid flows in a single direction across the tubes, and the other fluid moves through the tubes.

  • Multi-pass crossflow: The fluid inside the tubes can flow in multiple passes to increase the contact time with the fluid outside, improving heat transfer.

Efficiency Considerations:

  • Crossflow heat exchangers are generally less efficient than counterflow heat exchangers because the temperature gradient between the two fluids decreases along the length of the heat exchanger. In counterflow, the fluids maintain a more consistent temperature difference, which makes it more effective for heat transfer.

  • However, crossflow heat exchangers are easier to design and are often used in situations where space is limited or where fluids need to be separated (like in air-to-air heat exchangers).

Applications:

  • Air-cooled heat exchangers (like in HVAC systems or car radiators).

  • Cooling of electronic equipment.

  • Heat exchangers for ventilation systems.

So, while not as thermally efficient as counterflow heat exchangers, crossflow designs are versatile and commonly used when simplicity or space-saving is important.

What is the difference between the crossflow and counter flow heat exchangers?

The main difference between crossflow and counterflow heat exchangers lies in the direction in which the two fluids flow relative to each other.

  1. Counterflow Heat Exchanger:

    • In a counterflow heat exchanger, the two fluids flow in opposite directions. This arrangement maximizes the temperature gradient between the fluids, which improves heat transfer efficiency.

    • Benefit: The counterflow design is typically more efficient because the temperature difference between the fluids is maintained across the entire length of the heat exchanger. This makes it ideal for applications where maximizing heat transfer is crucial.

  2. Crossflow Heat Exchanger:

    • In a crossflow heat exchanger, the two fluids flow perpendicular (at an angle) to each other. One fluid typically flows in a single direction, while the other flows in a direction that crosses the first fluid’s path.

    • Benefit: While the crossflow arrangement is not as thermally efficient as counterflow, it can be useful when space or design constraints exist. It is often used in situations where the fluids must flow in fixed paths, such as in air-cooled heat exchangers or situations with phase changes (e.g., condensation or evaporation).

Key Differences:

  • Flow Direction: Counterflow = opposite directions; Crossflow = perpendicular directions.

  • 効率: Counterflow tends to have higher heat transfer efficiency due to the more consistent temperature gradient between fluids.

  • アプリケーション: Crossflow is often used where counterflow isn't feasible due to design limitations or space constraints.

最近の記事

最近のコメント

表示できるコメントはありません。

分類する

搭載 www.en159.com お問い合わせ kuns913@gmail.com

|テーマ： アポイントメントブルー ウェブリティ著

ヘルプが必要ですか?
ja日本語
en_USEnglish de_DEDeutsch fr_BEFrançais de Belgique ru_RUРусский pt_BRPortuguês do Brasil hi_INहिन्दी ko_KR한국어 es_CLEspañol de Chile pa_INਪੰਜਾਬੀ ja日本語