餘熱鍋爐（lú）是利用工業（yè）企業爐窯及其它餘熱熱源設備產生的餘熱而生產蒸汽或（huò）熱（rè）水的一種供熱設備。它與傳統意義上的鍋爐相比僅有“鍋”而沒有“爐”，但習慣上人們仍然稱它為“餘熱鍋（guō）爐”。由（yóu）於“餘熱”種類的多樣性從而使餘熱鍋爐的結構形（xíng）式各（gè）式各樣，不盡相同。餘熱是在工業生產中未被充分利用就排放掉的熱量，它屬於二次能源，是一（yī）次能（néng）源和可燃物料轉換（huàn）後的產物（wù）。
（一）按餘熱的性質可（kě）分為以下幾大類：
1.   高溫（wēn）煙（yān）氣（qì）餘熱：它是常見的一種形式，其（qí）特點（diǎn）是產量大、產點（diǎn）集中，連續性強，便於回收和利（lì）用（yòng），其帶走熱量占總熱量的（de）40~50%，該餘熱（rè）鍋爐回收熱（rè）量，可用於生產或（huò）生活用熱及發（fā）電。
2. 高溫爐渣餘熱：如高爐爐渣、轉爐爐（lú）渣、電爐爐渣等（děng），該爐渣溫度在1000℃以上，它帶走的（de）熱（rè）量占總熱量的20%。
3.高溫產品餘熱：如焦爐焦碳、鋼錠鋼坯、高溫（wēn）鍛件等，它一般溫度（dù）很高，含有（yǒu）大（dà）量餘熱。
4.可燃廢氣（qì）、廢液的餘熱（rè）：如高爐（lú）煤氣、煉（liàn）油廠的催化裂化再生廢氣、造紙廠的黑液等，它們都可以被利用。
5. 化學反應（yīng）餘熱：如冶金、硫酸、磷酸、化肥、化纖、油漆等工（gōng）業部門，都產生（shēng）大量的化學反應餘（yú）熱。
6.   冷卻介質餘熱：如工業爐窯的水套等冷卻裝置（zhì）排出的大量冷卻水，各種（zhǒng）汽（qì）化冷卻裝置產出（chū）的蒸汽都（dōu）含有大量的餘熱，它們都可以被合理利用。
7.   冷凝水餘熱：各工業部門生產過程用汽在工業過程後冷凝減小時所具（jù）有的物理（lǐ）顯熱。
（二）由於餘熱是與其它（tā）生產設備及工藝密切相關，故餘熱利用又具有以下（xià）特點（diǎn）：
1.  熱負荷不穩定，主要（yào）有工藝（yì）生產過程所決定。
2. 煙塵的（de）成分、濃度、粒度（dù）差別比較大。從而使鍋爐的受熱麵（miàn）布置受影響（xiǎng），須考慮防磨、堵灰及除（chú）塵。
3.煙氣成分的多樣性，使有的煙氣具（jù）有腐（fǔ）蝕性。如煙氣中的SO2 、煙塵或爐渣中的各種金屬和非金屬元素等（děng）都可能對（duì）餘熱設備產生低溫或高溫腐蝕和積灰。
4.受安裝物所固有條（tiáo）件的限製。如有（yǒu）的對（duì）鍋爐進、出煙口（kǒu）標高的限製；有（yǒu）的對鍋爐排煙溫度的（de）限製，使其滿足生產工藝的（de）要求。
（三）由於餘熱煙（yān）氣性（xìng）質的不同，故使餘熱鍋爐的種類、結構形式各不相同。按結構特點可分為管殼式餘熱鍋爐和煙道式餘熱（rè）鍋爐兩大類。按餘熱鍋爐進口煙氣含塵量（liàng）和煙氣特性又可分為以（yǐ）下五類：
1.  煙（yān）氣中含塵量不大於20g/Nm3的餘熱鍋爐為一類（lèi）餘熱鍋爐；
2.   煙氣中（zhōng）含塵量大於20g/Nm3且不大於70g/Nm3的餘（yú）熱鍋爐為（wéi）二類餘熱鍋爐；
3.  煙氣（qì）中（zhōng）含塵量（liàng）大（dà）於70g/Nm3的餘熱鍋（guō）爐為三類餘熱鍋爐；
4.  煙（yān）氣中含有粘結性煙塵的餘熱鍋爐為四類（lèi）餘熱鍋爐；
5.煙氣中含有強腐蝕成分或具有有毒煙氣的餘熱鍋爐為第五類餘熱（rè）鍋爐（lú）。

　　隨著能源供應的（de）緊張，使一些企業不斷提高“節能增效、降耗增產”的意識。因此餘（yú）熱鍋爐作為“降耗（hào）、增效”的設備不斷在能源消耗大的鋼鐵、化工、建材等行業得到用戶（hù）青睞。同時各個鍋爐廠家對餘（yú）熱鍋爐的開發力（lì）度（dù）和深度也逐漸加大，不斷開發（fā）出高性能的產品來占領、擴（kuò）大市（shì）場分額。我廠近幾年開發的餘熱鍋爐主要（yào）有碳素窯餘熱鍋爐、焦化餘熱鍋爐、水泥窯純低溫餘（yú）熱鍋爐、化工三廢混燃餘（yú）熱鍋爐、玻璃窯餘熱鍋爐等係列。其主要特點如下：
碳素窯餘熱鍋爐（lú）
　　碳素窯餘熱鍋爐為立式自然循環水管鍋爐，該型鍋爐為第一類餘熱鍋爐，其進口煙氣的（de）含塵量（liàng）一般為5g/Nm3左右（yòu）。其爐型（xíng）結構（gòu）布置新（xīn）穎，性能先進，同傳（chuán）統碳素回轉窯餘熱鍋爐相比，漏風小，密封性能好（hǎo），並且占地麵積小，節省（shěng）投資。

水泥窯純低溫餘熱鍋（guō）爐（lú）
　　根據水泥窯生產工藝設備及流程（chéng），應用於水泥行業純低溫餘熱係統的餘熱鍋爐分為窯頭（tóu）餘熱鍋（guō）爐和窯尾餘熱鍋爐。窯頭餘熱鍋爐進口煙氣來（lái）自水泥窯窯頭蓖冷機排出的熱空氣，其（qí）煙溫較低，含塵量（liàng）一般為15g/Nm3左右，結合（hé）實際情況，鍋爐受熱麵采用（yòng）厚（hòu）壁螺旋鰭片管，從而組織起（qǐ）更為有效的煙氣流場（chǎng），加強換熱。窯尾餘熱鍋爐進口煙氣（qì）來自水泥窯窯尾預熱器排出的煙氣，其煙溫（wēn）較低（dī），含塵量一般為70g/Nm3左右，粉塵含量大，運行（háng）中對受熱麵的磨損較嚴重，鍋（guō）爐受熱麵采用（yòng）厚壁光管 。
化工三廢混燃餘熱鍋爐
　　化工三廢混燃餘熱鍋爐適用於造氣爐三廢回收利用係統的餘熱爐，鍋爐采用單鍋筒的自然（rán）循環水管鍋爐，鍋爐按煙氣流動（dòng）方（fāng）向（xiàng）為立式或隧（suì）道（dào）式布置。
玻璃（lí）窯餘熱鍋爐
　　該型餘（yú）熱鍋爐利用新型（xíng）浮法玻璃熔窯尾部煙氣餘熱（rè）產（chǎn）生可供發電、生產、生活使用的蒸（zhēng）汽，不直接（jiē）使用一次性燃料，因此（cǐ）它具備節能和（hé）能源綜（zōng）合利用的特點。
　　本餘熱鍋爐采用單鍋（guō）筒橫置式的立（lì）式自然循環水管鍋爐，整體布置形式采用倒（dǎo）U型，受熱麵布置有對流（liú）管（guǎn）束和（hé）省煤器，各部分受熱（rè）麵采用模塊化（huà）結構，整（zhěng）裝出廠。

燒結機餘熱鍋爐
　　它是應用於鋼鐵行業的燒結機餘熱鍋爐，該鍋爐設計（jì）入口煙溫約330℃。流經鍋爐高（gāo）壓過熱器、高壓對流管束、高壓省煤器、低壓對流管束和熱水段，煙溫降（jiàng）至（zhì）136℃左右。
　　燒結機餘熱鍋爐熱源煙（yān）溫較（jiào）低，粉塵含量較小，為了（le）防止積灰（huī），提高鍋爐（lú）熱效率，達到實現鍋爐an全、穩定運行的（de）目的，本鍋爐結合實際運行情況，及其具體結（jié）構特點，在整個布（bù）置和（hé）設計中采取相應有效措施，鍋爐受熱麵采用厚壁螺旋鰭（qí）片（piàn）管，從而組織起更為有效的煙氣流場，加強換（huàn）熱，並且能在較大（dà）程度上減輕磨損，延長檢修周期，保證鍋爐有較長的使用年（nián）限。受熱麵的布（bù）置全部采用錯列形式，合（hé）理地安排（pái）管組的間距，從而既保證有足夠的煙速，達到所要（yào）求的換熱效果。
　　鍋爐牆選用輕型護板爐牆，降（jiàng）低了鍋爐漏風係數，從而滿足（zú）生產工藝和穩定發電（diàn）的需要。 

餘熱鍋爐在生產係（xì）統中（zhōng）的作用
　　由於生產係統及餘熱發（fā）電熱力係統的特殊性，鍋爐在整個係統中主要起到以下作用：
a)鍋爐起（qǐ）到降低整個煙氣溫度的作用，能夠（gòu）保障係統中除塵（chén）設備的正（zhèng）常運行，達（dá）到低溫環保排放煙氣；
b)鍋爐通過利用餘熱產生高溫高壓蒸汽通過與補燃鍋爐整體配套推（tuī）動氣輪機和發電機發電，為（wéi）整個水泥生產係統設備提供動力（lì）；
c)鍋爐具有一定的自除塵作用，分離出的灰塵可以（yǐ）重（chóng）新回收利用，達到“一機多用”的功能。
d) 利於降低整個係統能耗，做到能源的充分利用。 

餘熱鍋爐（lú）設（shè）計時所應具備的條件
1、煙氣側參數：
煙（yān）氣量、煙氣進口溫度、煙氣成分、煙氣含塵量、煙氣側壓（yā）力（正壓或負壓）、鍋爐（lú）煙氣側係統阻力
2、 鍋爐參數：
鍋爐額定蒸發量、鍋爐額定蒸汽壓力、鍋爐額定蒸汽溫度、鍋爐排煙溫（wēn）度
3、其它參數：
鍋爐安裝形（xíng）式、鍋爐結構形式、鍋爐（lú）安裝地氣象（xiàng）參數（shù）或其它特殊要求。

　　Waste heat boiler is the use of industrial enterprises and other waste heat heat source furnace heat generated by the equipment to produce steam or hot water heating equipment. 　　Compared with boilers in the traditional sense, it has only a "pot" and no "furnace," but people still call it "a waste heat boiler." Due to the variety of "excess heat" types, the structure of waste heat boilers varies from one type to another. Residual heat is the amount of heat that is emitted from an underutilized industrial production. It is a secondary energy and is the result of a conversion of energy and combustible materials.

(A) According to the nature of waste heat can be divided into the following categories:

1. High-temperature flue gas waste heat: It is a common form, which is characterized by large production, production points concentrated, continuous, easy to recycle and use, the heat taken away 40 to 50% of the total heat, the waste heat boiler Recovery of heat, can be used for production or living with heat and power generation.

2. High-temperature slag waste heat: such as blast furnace slag, converter slag, electric furnace slag, the slag temperature above 1000 ℃, it takes away the heat of 20% of the total heat.

3. High-temperature product waste heat: such as coke oven coke, steel billet, high-temperature forgings, etc., it is generally high temperature, containing a lot of waste heat.

4 combustible waste gas, waste heat: such as blast furnace gas, oil refinery catalytic cracking, waste black paper mills and so on, they can be used.

5 chemical reaction waste heat: such as metallurgy, sulfuric acid, phosphoric acid, chemical fertilizer, chemical fiber, paint and other industrial sectors, have a lot of chemical reaction heat.

6. Residual heat of cooling medium: If a large amount of cooling water is discharged from a cooling device such as a water jacket of an industrial kiln, the steam produced by various vaporizing and cooling devices contains a large amount of waste heat, all of which can be rationally used.

7. Condensate water waste heat: the industrial process steam used in the industrial process to reduce the condensation when the physical sensible heat.

(B) As the waste heat is closely related to other production equipment and processes, so waste heat utilization has the following characteristics:

1. Unstable heat load, the main process of the production process decision.

2. Soot composition, concentration, particle size difference is relatively large. So that the boiler heating surface layout affected, we must consider wear-resistant, blocking ash and dust.

3. The diversity of flue gas composition, so that some flue gas corrosive. Such as flue gas SO2, soot or slag in a variety of metals and non-metallic elements, etc. may waste heat equipment, low temperature or high temperature corrosion and fouling.

4 by the installation of the inherent conditions of the restrictions. For example, there are restrictions on the entrance and exit heights of boilers, and some restrictions on the temperature of boiler exhaust smoke make it meet the requirements of the production process.

(C) Due to the different nature of the residual heat flue gas, so the type of waste heat boiler, the structure of different forms. According to the structural characteristics can be divided into shell and tube waste heat boiler and flue-type waste heat boiler two categories. Waste heat boiler imports of flue gas dust and flue gas characteristics can be divided into the following five categories:

1. The waste heat boiler with dust content not more than 20g / Nm3 in the flue gas is the first type of waste heat boiler;

2. Waste heat boiler with dust content greater than 20g / Nm3 and not more than 70g / Nm3 in flue gas is the second type waste heat boiler;

3. Waste heat boiler with dust content greater than 70g / Nm3 in flue gas is the third type waste heat boiler;

4. Flue gas containing cohesive soot and waste heat boiler for the fourth category waste heat boiler;

5. Waste heat boilers with strong corrosion components or toxic fumes are the fifth type of waste heat boilers.

With the tight supply of energy, some enterprises have continuously raised their awareness of “energy saving, efficiency enhancement, and consumption reduction and production increase”. Therefore, waste heat boiler as "the preferred equipment for reducing consumption and increasing efficiency" is continuously favored by users in such industries as steel, chemical industry and building materials with high energy consumption. At the same time, various boilers and manufacturers of waste heat boiler development efforts and depth gradually increased, and constantly develop high-performance products to occupy and expand market share. In recent years I plant the waste heat boiler developed mainly carbon kiln waste heat boiler, coking waste heat boiler, cement kiln pure low temperature waste heat boiler, chemical waste waste heat boiler, glass kiln waste heat boiler series. Its main features are as follows:

Carbon kiln waste heat boiler

Carbon kiln waste heat boiler is a vertical natural circulation water tube boiler, which is the first type of waste heat boiler, the dust content of imported flue gas is generally about 5g / Nm3. Its furnace structure layout novel, advanced performance, with the traditional carbon rotary kiln waste heat boiler, air leakage is small, good sealing performance, and covers an area of small, save investment.

Cement kiln pure low temperature waste heat boiler

According to the cement kiln production process equipment and processes, the waste heat boiler used in the pure low temperature waste heat system of the cement industry is divided into a kiln waste heat boiler and a kiln waste heat boiler. The imported flue gas from kiln waste heat boiler comes from the hot air discharged from the kiln cooler of kiln cement kiln. The flue gas temperature is low and the dust content is about 15g / Nm3. According to the actual situation, the heating surface of the boiler adopts thick-walled spiral fin tube , So as to organize a more effective flue gas flow field and enhance heat exchange. Kiln waste heat boiler inlet flue gas from the cement kiln kiln exhaust preheater flue gas, the lower the flue gas temperature, the amount of dust is generally about 70g / Nm3, dust content, the operation of the heating surface of the more serious wear and tear, Boiler heating surface using thick-walled light pipe.

Chemical waste mixed waste heat boiler

The chemical wastes waste heat boiler is suitable for the waste heat recovery furnace of the waste gas recycling system of three waste gas generators. The boiler uses the natural circulation water boiler of the single drum, and the boiler is arranged vertically or tunnelly according to the flowing direction of flue gas.

Glass kiln waste heat boiler

The waste heat boiler utilizes the residual flue gas waste heat from the rear of the new float glass furnace to generate steam for power generation, production and life. It does not use disposable fuel directly, so it has the characteristics of energy saving and comprehensive utilization of energy.

The waste heat boiler adopts single-drum horizontal type vertical natural circulation water boiler, the overall layout adopts inverted U-shaped, heating surface is arranged with convection tube bundle and economizer, the heating surface of each part adopts modularized structure and is assembled and shipped out of factory.

Sintering machine waste heat boiler

It is a sintering machine waste heat boiler used in the iron and steel industry. The inlet smoke temperature of this boiler is about 330°C. Flow through the boiler high pressure superheater, high pressure convection tube bundles, high pressure economizer, low pressure convection tube bundles and hot water sections, smoke temperature dropped to about 136 °C.

In order to prevent fouling and improve the boiler thermal efficiency and achieve the goal of safe and stable operation of the boiler, the boiler combined with the actual operation and the specific structural characteristics of the heat exchanger in the entire layout And the design to take appropriate and effective measures, the boiler heating surface with thick-walled spiral fin tube, which organized more effective flue gas flow field, to enhance heat transfer, and to a greater extent reduce wear and tear, extending maintenance intervals, to ensure Boilers have a longer useful life. The heating surface of the layout of all staggered form, a reasonable arrangement of pipe spacing, which not only ensure adequate smoke speed, to achieve the required heat transfer.

Boiler wall light armored wall selection, reducing the boiler air leakage coefficient, so as to meet the production process and the need for stable power generation.

The role of waste heat boilers in production systems

Due to the particularity of the production system and the thermal system of waste heat power generation, the boiler mainly plays the following roles in the whole system:

a) The boiler plays the role of reducing the temperature of the entire flue gas, can ensure the normal operation of the dust removal equipment in the system and achieve the emission of flue gas at low temperature and environmental protection;

b) The boiler generates high-temperature and high-pressure steam by using the waste heat, and drives the gas turbine and the generator to generate power for the entire cement production system and equipment through the whole package with the afterburning boiler;

c) The boiler has a certain self-dedicated function. The separated dust can be recycled and used to achieve the function of “one machine with multiple functions”.

d) help reduce the energy consumption of the entire system, make full use of energy.

Waste heat boiler design should have the conditions

1, the flue gas side parameters:

Flue gas volume, flue gas inlet temperature, flue gas composition, flue gas dust content, flue gas side pressure (positive or negative pressure), boiler flue gas side system resistance

2, the boiler parameters:

Boiler rated evaporation, boiler rated steam pressure, boiler rated steam temperature, boiler exhaust temperature

3, other parameters:

Boiler installation form, boiler structure, boiler installation site weather parameters or other special requirements.