一步法回轉窯生產還原鐵熱壓塊項目

One-step Rotary Kiln Producing Reducing Iron Hot-pressing Block Project

工藝說明

Technical proposal

一、工藝簡介

       Introduction of the Process

       1、還原鐵熱壓塊(HBI)生產工藝

             Production Process of Reduced Iron Hot-pressing Block (HBI)

用天然氣或煤氣做熱源的回轉窯還原技術+熱壓成型鈍化機壓塊是我公司最新研發生產還原鐵熱壓塊新工藝技術，新工藝節能環保，已經申報國家發明專利。我公司研發的回轉窯+熱壓成型鈍化工藝，與傳統工藝有了很大改進，用天然氣或煤氣做熱源，用CO氣體和無煙煤做還原劑，不但回轉窯操作變得簡單，回轉窯結圈幾率降低，運行更可靠，同時由于增加了熱壓成型鈍化系統，最大限度防止了再氧化和利用了余熱，降低了能耗和生產成本。

Rotary kiln reduction technology with natural gas or gas as heat source and passivator pressing block by hot pressing are the latest research and development of new technology for producing reduction iron hot pressing block by our company. The new technology is energy-saving and environmental protection, and has declared the national invention patent. It not only makes rotary kiln operation easy, Rotation kiln ringing rate becomes lower and the operation is more reliable. At the same time, due to the addition of passivation system for hot pressing forming, the waste heat is maximally utilized, and the energy consumption and production cost are reduced.

該工藝主要針對鐵礦粉或氧化鐵皮進行還原，所用原料有鐵礦粉（氧化鐵皮）、還原劑（CO+無煙煤）及脫硫劑。主要設備包括配料壓球系統、烘干加熱系統、二次燃燒室系統、回轉窯還原系統、熱壓成型鈍化系統、尾氣抽風凈化系統、噴煤系統和循環水冷卻系統等。

The process is mainly aimed at reducing iron ore powder or oxide scale. The raw materials used are iron ore powder (oxide scale), reducing agent (CO + anthracite) and desulfurizer. The main equipments include batching and ball-pressing system, drying heating system, secondary combustion chamber system, rotary kiln reduction system, hot pressing passivation system, exhaust air purification system, coal injection system and circulating water cooling system etc.

主要工藝流程是鐵粉、氧化鐵皮、粘結劑按一定比例混合后，通過皮帶機輸送到強制混料機中，經過強制攪拌混合的料通過皮帶機進入儲料倉中，儲料倉4個，下面安裝有圓盤給料機，可根據壓球機產量調節圓盤給料機給料量，鐵粉料通過皮帶機加到壓球機中，壓球機壓好的球，通過皮帶機進入鏈板式烘干機中。鐵粉球在鏈板式烘干機中被來自燒結回轉窯的熱風烘干加熱，二次燃燒室排出的高溫尾氣直接進入燒結回轉窯，燒結回轉窯燒結的球團,溫度高達11０0℃，密閉送進還原回轉窯中進行加熱還原，經回轉窯還原的高溫還原球團在窯頭出料口進行篩分，篩下物加濕降溫后有螺旋上料機排出，費焦經處理后，顆粒料可以繼續使用。篩上的熱還原球團經壓塊機進行熱壓鈍化處理，最終出還原鐵熱壓塊（HBI）產品。

The main process is that after mixing iron powder, iron oxide scale and binder in a certain proportion, the material is conveyed to the forced mixer through belt conveyor. After forced mixing, the material is entered into the storage bin through belt conveyor. There are four storage silos with disc feeders installed below. The feeding quantity of disc feeder can be adjusted according to the output of ball press. Iron powder is added to the ball press through belt conveyor. The ball pressed by the machine enters the chain plate dryer through the belt conveyor. Iron powder pellets are heated by hot air drying from sintering rotary kiln in chain plate dryer. The high temperature tail gas from secondary combustion chamber enters sintering rotary kiln directly. The sintered pellets in sintering rotary kiln are fed to reduction rotary kiln at a temperature as high as 1100 C. The high temperature reduction pellets reduced by rotary kiln are screened at the outlet of kiln head, and the sieve material is humidified and cooled. The screw feeder discharges the coke, after treatment, the granular material can continue to use. The hot reduction pellets on the sieve were passivated by hot pressing with a compactor, and the reduced iron hot pressing block (HBI) product was finally produced.

2、設備工藝布置圖

          Equipment Process Layout

   3、天然氣回轉窯還原技術+熱壓成型鈍化工藝主要特點

    The Features of Reduction Technology + Hot Pressing Passivation Technology for Natural Gas Rotary Kiln

 用天然氣或煤氣做熱源的回轉窯還原技術，再配加二次燃燒室+成品篩分熱壓塊以后，生產工藝與傳統的回轉窯藝有了很大的區別。

 Reduction technology of rotary kiln using natural gas or gas as heat source and adding secondary combustion chamber + finished product sieving hot pressing block, the production process is quite different from the traditional rotary kiln process.

 1）、回轉窯長度變短，一般在40m-60m左右,使投資減少；同時由于回轉窯變短，回轉窯熱平衡極易建立，操作變得簡單。由于物料在窯內時間變短，同時由于還原采用無煙煤顆粒，強度好，摩擦產生的粉末減少，使窯爐爐襯結圈幾率降低 ，設備運行更可靠；

      1）、The length of the rotary kiln becomes shorter, generally about 40m-60m, so that the investment is reduced; at the same time, as the rotary kiln becomes shorter, the heat balance of the rotary kiln can be easily established and the operation becomes easier. As the material in the kiln becomes shorter, at the same time, anthracite particles are used for reduction., the iron powder produced by the friction is reduced, so that the kiln furnace liner lining is less likely to be ringed, and the equipment operation is more reliable.

      2）、特殊的加熱燃燒和噴煤方式及回轉窯二次風機，使回轉窯內溫度均勻，還原區溫度基本在1100℃～1150℃；

The special coal injection method and secondary fan of rotary kiln make the temperature of the short rotary kiln uniform and the kiln tail temperature reaching 1100 ~ 1150 degrees;

 3）、由于尾氣中富含煤氣，設立二次燃燒室可以燃燒掉尾氣中的CO等可燃成分，不僅可以使尾風溫度提高到1150℃，而且利用尾風也可保證安全可靠；

Because the exhaust gas is rich in gas, setting up a secondary combustion chamber can burn off the combustible components such as CO in the exhaust gas, which can not only raise the temperature of the exhaust to 1150 C, but also ensure the safety and reliability of the exhaust.

 4）、回轉窯排出的混合還原料，經特制高溫震動篩處理后，純凈高溫還原球團直接進入熱料壓機熱壓鈍化處理，熱壓塊密度可達6.5-6.8t/m3；

the mixed reducing material discharged from rotary kiln is treated by special high temperature shaking screen. The pure high temperature reducing pellet is directly passivated by hot pressing machine. The density of hot pressing pellet can reach 6.5-6.8t/m.

5）、對篩分出的廢焦進行處理，大于2mm顆?？梢岳^續使用，減少了還原劑使用量，降低生產成本；

The sifted waste coke can be treated, and particles larger than 2mm can be used continuously, which reduces the amount of reductant used and reduces the production cost.

      6）、用天然氣或煤氣作為熱源，CO+煤炭顆粒還原，尾氣含塵量大大降低，經除塵器處理后完全可以達到規定的尾氣排放標準。

Natural gas or gas is used as heat source and CO + coal particles are reduced, the dust content of tail gas is greatly reduced, and the tail gas can completely meet the prescribed emission standard after being treated by dust collector.

 7）、二次燃燒室將尾氣中可燃成分燃燒后排出的高溫尾氣首先進入燒結回轉窯對球團加熱燒結，然后再進入鏈板式加熱器對冷球團進行烘干，最大限度利用熱能，提高能源利用率，降低成本。

The high-temperature exhaust gas from the combustible components in the tail gas of the secondary combustion chamber first enters the sintering rotary kiln to heat and sinter the pellets, and then enters the chain-plate heater to dry the cold pellets, so as to maximize the use of heat energy, improve the utilization rate of energy and reduce costs.

4、原材料工藝要求

The requirement of the raw material

 1）鐵粉（鐵礦石）

Iron powder

   鐵粉TFe≥68%，粒度＞80目

    Iron powder TFe≥68%, particle size>80 mesh

  2）還原劑

Reducing agent

    本項目還原劑為無煙煤，每噸球團需要450Kg，無煙煤粒度為10mm-20mm.

   The reducing agent of this project is anthracite. Each ton of pellets needs to 450 Kg. Anthracite particle size is 10 mm-20 mm.

    3）石灰石

    Limestone

    CaO含量＞55%，粒度小于5mm

    CaO content > 55%, particle size less than 5 mm

     4）天然氣

    Natural gas

     天然氣熱值＞8000大卡

    Calorific value of natural gas > 8000 calories

 5、產品要求

     Product requirement

1）、金屬化率

metallization rate

產品平均金屬化率90%-92%，含碳量0.5-1%

The average metallization rate of products is 90%-92%, and the carbon content is 0.5-1%.

1）      產品形狀

Shape of the product

    產品為直接還原鐵熱壓塊（MBI），還原鐵塊外形為直徑200-220mm,高度150-200mm的圓柱體，密度6.0-6.5t/m3。

The product is directly reduced iron hot pressing block (HBI). The shape of reduction iron block is a cylinder with diameter of 200-220 mm and height of 150-200 mm. Its density is 6.0-6.5 t/m

　二．各系統工藝要求

          Technological requirements of each system

          1．  配料壓球系統

       Batching and Ball-pressing system

鐵粉、氧化鐵皮、粘結劑分別裝入給料倉，通過可調給料機、皮

帶秤將三種原料按照工藝要求比例給入混料皮帶，由混料皮帶機將混合料裝入強制混料機中進行攪拌。攪拌混合均勻的料進入儲料倉，通過圓盤給料機和皮帶機將攪拌好的料送到高壓壓球機，用高壓壓球機將鐵粉料壓成冷固球團，形狀為扁圓形，尺寸φ30*20mm, 冷固球團由皮帶機送到鏈板烘干機進行烘干預熱。

Iron powder, iron oxide scale and binder are respectively loaded into the feeding bin, and three kinds of raw materials are proportionally fed into the mixing belt according to the technological requirements by adjustable feeder and belt conveyer. The belt conveyor loads the mixture into the forced mixer for mixing. Mixing uniform material into the storage bin, through the disc feeder and belt conveyor, the mixing material is sent to the high-pressure ball presser. The iron powder is pressed into cold-solidified pellets by high-pressure ball presser. The shape of the pellets is flat circular and the size isφ30*20mm. The cold-solidified pellets are sent by belt conveyor to chain plate dryer for heating intervention.

    2．  鏈板式烘干機

     Chain plate dryer

     鏈板烘干機分成１０個風箱，分為烘干段加熱段，烘干段6個風室，預熱段４個風室。

     Chain plate dryer is divided into 10 bellows, which are divided into heating section of drying section, 6 air chambers of drying section and 4 air chambers of preheating section.

       2.1烘干段

            drying section

含水8%左右的合格冷壓球在烘干段內，首先被從烘干機預熱風箱引來的熱氣進行抽風干燥。為了保證含大量水分的冷壓球球在烘干段內不發生爆裂，要求熱氣溫度，前3個風箱應嚴格控制在300℃以下，后3個風箱400℃-500℃。對料層進行干燥，使冷壓球團脫水、干燥、升溫。

In the drying section, the qualified cold-pressed balls with about 8% water content are first pumped and dried by hot air from the preheater of the dryer. In order to ensure that the cold-pressed ball with a lot of water does not burst in the drying section, the temperature of hot air is required. The first three bellows should be strictly controlled below 300 C, and the last three bellows should be controlled between 400 C and 500 C. The material layer is dried to dehydrate, dry and heat the cold-pressed pellets.

從風箱抽出的廢熱氣，經電除塵和脫硫處理后，由主抽風機經煙囪排入大氣。烘干段長度18米。

The exhaust hot gas extracted from the bellows is treated by electrostatic precipitation and desulfurization, and is discharged into the atmosphere by the main exhaust fan through the chimney. The length of drying section is 18 meters.

      2.2預熱段

            preheating section

在預熱段，５０0℃-６５0℃熱氣流通過料層使生球繼續升溫。

預熱段主要熱源為來自燒結回轉窯排出的熱風，回風由回熱風機打入烘干段?；責犸L機進風端和出風端都安裝熱電偶，回熱風機進風端熱電偶前能夠補冷風，補風量可調，以確?；責犸L機進風不得超過550℃。

   In the preheating stage, the hot air flow from 500 ~650 ℃passes through the material layer to keep the green balls warming up.

The main heat source in the preheating section is the hot air discharged from the sintering rotary kiln, and the return air is driven into the drying section by the regenerative fan. Thermocouples are installed at both the inlet and outlet ends of the regenerative fan. Before the thermocouples at the inlet end of the regenerative fan, the cooling air can be compensated and the air supply volume can be adjusted to ensure that the inlet air of the regenerative fan cannot exceed 550 ℃.

回熱風機溫度不超550℃，風壓5600Pa。

    The temperature of the regenerative fan does not exceed 550 C and the air pressure is 5600Pa.

預熱段長度１２米。

 The length of preheating section is 12 meters.

烘干預熱后的冷壓球團通過輸送機密閉進入燒結回轉窯進行加熱，溜料管安裝溜篩，篩出小于５mm碎料，碎料送到攪拌機重新攪拌。鏈板烘干機排出的尾氣低于220℃，經過布袋除塵器除塵后由主抽風機打入煙筒排放。

After baking, the cold-pressed pellets are heated in the sintering rotary kiln by conveying confidentially. The chute pipe is equipped with a chute, and the crushed materials less than 5 mm are screened out. The crushed materials are sent to the mixer for re-stirring. The tail gas discharged by chain plate dryer is below 220 C, which is discharged by the main exhaust fan into the chimney after dust removal by bag filter.

3、燒結回轉窯

 Sintering rotary kiln

二次燃燒室熱風溫度在1１５0℃，直接進入燒結回轉窯，對球團進行加熱燒結，提高球團強度。燒結回轉窯排出的熱風，直接進入鏈板烘干機預熱段，燒結回轉窯排出的熱球團（溫度達到１０５0℃）密閉進入還原回轉窯。

The hot air temperature in the secondary combustion chamber is 1150 C, and the pellets are directly heated and sintered in the sintering rotary kiln to improve the strength of the pellets. The hot air discharged from the sintering rotary kiln directly enters the preheating section of the chain dryer, and the hot pellets discharged from the sintering rotary kiln (temperature up to 1050 C) are sealed into the reduction rotary kiln.

4、二次燃燒室系統

Secondary Combustor System

回轉窯排出的熱風，溫度約１００0℃，密閉進入二次燃燒室燃燒，。排出的煙氣溫度約1１５0℃,高溫煙氣進入燒結回轉窯對球團進行加熱燒結，同時二次燃燒室還有對尾氣沉淀除塵功能

The hot air discharged from the rotary kiln, with a temperature of about 1000 C, enters the secondary combustion chamber and combusts in an airtight way. The exhaust flue gas temperature is about 1150 C. The high temperature flue gas enters the sintering rotary kiln to heat and sinter the pellets. At the same time, the secondary combustion chamber has the function of precipitation and dust removal of the tail gas.

二次燃燒室安裝有助燃風機，風量可調，在二次燃燒室上有三排燒嘴，用于燒點回轉窯尾氣中的CO等可燃氣體，提高尾氣溫度，避免后續工序操作隱患。

The secondary combustion chamber is equipped with a combustion-supporting fan with adjustable air flow. There are three rows of burners in the secondary combustion chamber for burning combustible gases such as CO in the tail gas of rotary kiln, so as to raise the tail temperature and avoid the hidden dangers in the subsequent operation.

二次燃燒室出口安裝尾氣取氣點，隨時觀察進出二次燃燒室氣體中CO和O2含量，以便更好調整助燃風機風量，保證CO全部燃燒掉。

The exhaust gas intake point is installed at the outlet of the secondary combustor, and the CO and O2 contents in the gas entering and leaving the secondary combustor are observed at any time, so as to better adjust the air flow of the combustion-supporting fan and ensure that all CO is burned out.

二次燃燒室進出口安裝有測溫點，在操作室和中控室隨時可觀察進風和出風溫度。

Temperature measuring points are installed at the inlet and outlet of the secondary combustion chamber. The inlet and outlet temperatures can be observed at any time in the operation room and the central control room.

燒結回轉窯多余熱風由換熱風機牽引進入換熱器，換出的熱風溫度可達４００℃，用作還原回轉窯、二次燃燒室及燒結回轉窯助燃風，換熱后的尾風，溫度約５００℃，由換熱風機打進烘干機，對鐵粉進行烘干，最大限度利用熱能。

The excess heat air of sintering rotary kiln is pulled into the heat exchanger by the heat exchanger fan, and the temperature of the hot air exchanged can reach 400 C. It can be used as the combustion-supporting air of reduction rotary kiln, secondary combustion chamber and sintering rotary kiln. The tail air after heat exchange has a temperature of about 500 C. It is driven into the dryer by the heat exchanger fan to dry the iron powder and maximize the use of heat energy.

5、回轉窯還原系統

Rotary kiln reduction system

燒結后的冷壓球團（或鐵礦石）從燒結回轉窯經過溜槽進入還原回轉窯，并隨回轉窯沿周邊翻滾同時沿軸向朝窯頭移動，并在折返線的作用下部分返回一定距離，以此延長留窯時間?；剞D窯烘窯、加熱用天然氣做熱源，窯內溫度達到1000℃時開始噴煤并開始給料。

The sintered cold-pressed pellets (or iron ore) enter the reduction rotary kiln through chute from the sintering rotary kiln, roll along the periphery of the rotary kiln and move along the axis of the kiln head, and return to a certain distance under the action of the return line, thus prolonging the kiln retention time. Gas is used as heat source for drying and heating of rotary kiln. Coal injection and feeding are started when the temperature in the kiln reaches 1000 C.

在窯頭裝有專門設計的天然氣燒嘴，通過調整助燃風量和天然氣量，調節控制天然氣燃燒和火焰形狀，對窯內物料進行加熱。同時窯頭還裝有２只蘭碳噴槍，在回轉窯正常工作時使用。

A specially designed natural gas burner is installed at the kiln head to heat the material in the kiln by adjusting the amount of combustion air and natural gas, adjusting and controlling the combustion and flame shape of natural gas. At the same time, the kiln head is equipped with two blue carbon spraying guns, which can be used in the normal operation of the rotary kiln.

回轉窯開始加料后，由粒煤噴槍在窯頭噴入粒度10～20mm的煤碳，噴吹量為：300kg-400kg/噸球團。

After feeding in rotary kiln, coal with particle size of 10-20 mm was injected into the kiln head by granular coal spray gun, and the injection amount was 300 kg-400 kg/ton pellets.

在窯尾配加粒度1～１０mm的回收焦丁，配加量50～100kg/噸球團。

In the end of the kiln, the recovered coke butadiene with particle size of 1-10 mm is added, and the dosage is 50-100 kg/ton pellets.

球團在窯內主要受熱輻射作用，邊翻滾邊還原。球團還原溫度1060～1150℃，靠二次風和天然氣量來調整溫度。窯體溫度監測點位７個，采用有線傳輸測溫。

The pellets in the kiln are mainly subjected to heat radiation and are reduced by rolling. The reduction temperature of pellets ranges from 1060 to 1150 C. The temperature is adjusted by secondary wind and natural gas. There are 7 monitoring points for kiln temperature, which are measured by wired transmission.

窯體風機７個，風壓2000Pa。噴吹風管由特殊耐熱鋼鑄造，安裝時考慮拆卸方便。窯體二次風機給風的風量可調，確?；剞D窯內還原溫度。

There are 7 kiln blowers with air pressure of 2000 Pa. The injection air duct is cast by special heat-resistant steel. It is easy to disassemble when it is installed. The air flow rate of the secondary fan in the kiln body can be adjusted to ensure the reduction temperature in the rotary kiln.

噴槍與測溫系統連鎖，可以自動控制，也可以手動控制。

The spray gun is interlinked with the temperature system, which can be controlled automatically or manually.

窯頭和窯尾罩采用新型密封裝置。

New sealing devices are used for kiln head and kiln tail cover.

還原球團通過回轉窯窯頭罩內溜槽和固定篩卸到保溫箱內。

Reduced pellets are discharged into the insulating box through chutes and fixed sieves in the head cover of rotary kiln.

根據產量要求選用回轉窯型號，進料和出料端為減小耐材重量，用鋼板收口，收口處耐材厚度3５0mm。球團在回轉窯中停留時間約７h?；剞D窯選擇變頻調速電機調速。

Rotary kiln type is selected according to the output requirement. In order to reduce the weight of refractories at the feed and discharge ends, steel plate is used to close the inlet and the thickness of refractories at the closure is 350 mm. The residence time of pellets in rotary kiln is about 7 hours. The rotary kiln chooses variable frequency speed regulating motor to speed up.

6、熱壓成型鈍化系統

Passivation System for Hot Press Forming

還原高溫球團通過回轉窯窯頭罩內溜槽進入保溫箱內，經特質高溫震動篩篩分，將>15mm還原球團篩出，設計時要考慮溜篩角度，使其容易流料，＜15mm尾料料流入降溫設備，由風力輸送系統送到尾料處理場。

Reduced high temperature pellets enter the incubator through the chute in the head cover of rotary kiln. After screening by special high temperature vibration, the reduction pellets > 15mm are screened out. The angle of the sieve angle should be considered in the design to make it easy to flow. The less than 15mm tailings flow into the cooling equipment and are sent to the tailings disposal yard by the wind power conveying system.

>15mm高溫還原球經卷揚提升后，在高溫狀態下，液壓壓塊機壓成25Kg左右熱壓還原鐵塊，由鏟車運至成品壓塊場地。

   After hoisting and lifting the >15mm high temperature reduction ball, under the high temperature condition, the hydraulic press presses the reduction iron block into about 25kg hot pressure, which is transported by forklift truck to the finished product pressing site.

7、尾氣抽風凈化系統

Exhaust air purification system

鏈板式烘干機排出的熱廢氣，經除塵器除塵后由主抽風機打入脫硫系統，脫硫處理后經煙囪排入大氣。煙氣溫度大于150℃，最高溫度220℃，風量２０萬m3（工況），風壓5６00Pa,含塵濃度100mg/ N m3。

The hot exhaust gas discharged by chain plate dryer is pumped into the desulfurization system by the main exhaust fan after dust removal by the dust collector, and then discharged into the atmosphere by the chimney after desulfurization treatment. The flue gas temperature is over 150 C, the highest temperature is 220 C, the air volume is 200,000 m3 (working condition), the air pressure is 5600 Pa, and the dust concentration is 100 mg/N M.

排出煙氣灰塵濃度小于30mg/Nm3，H2S氣體含量小于10mg/ Nm3,

SO2氣體含量不得超過800ppm。

The exhaust dust concentration is less than 30mg/Nm and the H2S content is less than 10mg/Nm., SO2 content should not exceed 800 ppm.

除塵器及風機入口設計測溫點，在操作室和中控室能隨時監測尾氣溫。

Temperature measuring points is designed for dust collector and fan entrance can monitor tail temperature in operation room and central control room at any time.

設計中風機進、出口與連接管道間采用了軟連接，風機出口管道上設有管道消聲器，用以控制風機噪聲，以滿足《工業企業噪聲控制設計規范》的要求。

Soft connection is adopted between the inlet and outlet of the fan and the connecting pipes in the design. A pipe muffler is installed on the outlet pipes of the fan to control the noise of the fan, so as to meet the requirements of the Code for the Design of Noise Control in Industrial Enterprises.

8、尾料加工系統

Tailings processing system

篩下廢蘭炭經過加濕降溫后，由風力輸送系統送到尾料處理場。顆粒料收到顆粒料倉內，細粉由布袋除塵器收集。經磁選處理后顆粒料可以加入回轉窯做還原劑重新回收利用。

After humidification and cooling, the waste orchid charcoal is sent to the tailings treatment plant by the wind conveying system. The granular material is received in the granular silo, and the fine powder is collected by the bag filter. After magnetic separation, granular material can be added to rotary kiln as reductant and recycled.

三、制造成本

Manufacturing cost                         

                        單位：  /噸海綿鐵

UNIT:    /T Sponge Iron