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3. Operation Manual for SCR System
SCR系统运行说明
3.1 General principle of the SCR DeNOx Process (SCR脱硝工艺概述)
In the SCR DeNOx Process, NOx is reduced with ammonia over a catalyst to harmless nitrogen and water without forming any secondary pollution. The chemical reactions, which take place, are as follows:
在SCR脱硝工艺中，氮氧化物在催化剂作用下被氨还原为无害的氮气和水，不产生任何二次污染，其化学反应如下：
4NH3 + 4NO + O2 → 4N2 + 6H2O
6NO2 + 8NH3 → 7N2 + 12H2O
The above reactions may take place in the homogeneous gas phase at temperature of 900~1100 oC without the use of catalysts but in the SCR DeNOx process, the reactions typically take place at temperatures of 250~450 oC with the use of catalysts.
上述化学反应在不使用催化剂时也许可在900~1100 oC的均匀气相下进行，而在SCR脱硝工艺中，因使用了催化剂，反应通常可在温度250~450 oC下进行。由于使用了特殊的催化剂，该工艺可在低温（低至约200 oC）， 。图1为SCR脱硝工艺的示意图。
Figure 1 The SCR DeNOx Process （SCR脱硝工艺示意图）
The main components of the plant consist of a reactor with catalysts as well as a storage tank and an injection system for the reducing agent.
SCR脱硝工艺装置的主要组成部分包括一个装催化剂的反应器、一个储罐及一个还原剂注入系统。
Anhydrous ammonia is stored under a pressure given by temperature of the storage tank (e.g. 10bar at 20 oC).
The ammonia is depressurised and evaporated by means of steam, hot water or electricity in an evaporator. Then, the evaporated ammonia is diluted with air and injected in the flue gas by means of an injection system consisting of a large number of injection nozzles to obtain a homogeneous distribution of ammonia and flue gas. Alternatively, a small number of nozzle may be used in combination with a static mixer.
无水液氨的储存压力取决于储罐的温度（例如20 oC时压力为10bar）。液氨通过蒸发器中的蒸汽、热水或电被减压并蒸发。然后，蒸发的氨气经空气稀释，通过注入系统被注入到烟气中。注入系统有许多注射喷嘴组成，为的是获得氨和烟气的均匀分布。另一方面，在喷嘴数量较少的情况下，可以结合一个静态的混合器一起使用。
The SCR DeNOx reactor(Figure 2) is normally a rectangular container, which normally contains two or more separate layers of catalyst modules resting on a suitable support structure..
SCR 脱硝反应器（图2）一般是一个矩形的容器，通常包括放置在合适的静止支撑架上的两个或更多个独立的催化剂模块。
Figure 2 SCR DeNOx reactor（SCR脱硝反应器）
3.2 System Description for SCR System(SCR系统说明)
3.2.1 SCR Reactors and auxiliary system(SCR反应器和辅助系统)
The SCR reactor and auxiliary system is designed to meet the NOx removal requirement as
specified in the performance guarantees. The SCR reactor and auxiliary system consist of inlet & outlet duct with expansion joint, guide vanes, ash hopper, vertical housing, rectifier, slot and supports for the catalyst module, catalyst and soot blowing equipment.
为了满足性能保证所要求的NOx脱除效率，设计SCR反应器和辅助系统。SCR反应器和辅助系统由带膨胀节的进、出口烟道，导向板，灰斗，立式反应器，整流装置，催化剂模块的方形框和支撑，催化剂和吹灰装置组成。
1) SCR Reactor SCR反应器
The SCR reactor contain the catalyst required to assist the ammonia in removing the NOx. and Two(50%×2/unit) SCR reactors are located between economizer and gas side the air preheater
SCR反应器包括能够帮助氨除去氮氧化物的催化剂。两台(50%X2/机组)SCR反应器位于锅炉省煤器和空气预热器之间。
The SCR reactors are designed to accommodate sufficient catalyst to achieve guaranteed NOx reduction rate and ammonia slip.
SCR反应器的设计是为了供给足够的催化剂来保证NOx还原率和氨的逃逸率。
(1) Catalyst and Module 催化剂和模块类型
The catalyst type recommended for Taishan is DNX-864 which is a type developed for operation in a high-dust environment, typically in SCR units on coal-fired boilers. The DNX-864 catalyst has a hydraulic diameter of 6.4 mm corresponding to a pitch of approximately 7.2 mm.
为台山项目[s:152]的催化剂型号是DNX-864，适用于烟尘含量高的环境。特别是对燃煤锅炉的SCR系统。DNX-864催化剂的水力直径为6.4 mm，相当于孔径7.2mm。
The catalyst will be supplied in the form of VE422EE- and VE422EES-modules, each holding 16 cassettes. The size of the module is approximately L x W x H = 1.88 m x 0.95 m x 1.45 m and the weight is approximately 900 kg. The module includes a top grid with a wire mesh. The top grid has sufficient strength to allow walking on it.
催化剂将以VE422EE和VE422EES模块的形式提供，包括16个催化盒。模块的尺寸大约为L×W×H=1.88m×0.95m×1.45m ，重量大约为900kg。模块包括一个顶部钢丝网栅格，此栅格由足够的强度支撑步行。
2) Soot Blowing System 烟气吹扫系统
The soot blowing system, which utilizes superheated steam as the blowing medium are
supplied to prevent plugging problem from the catalyst surface. The superheated steam is to be taken from the steam source located at near SCR DeNOx facilities.
烟气吹扫系统以过热蒸汽为吹扫介质，用来防止催化剂表面堵塞。过热蒸汽源布置在SCR脱硝设备附近。
The soot blowers are designed to be automatically operated at desired time intervals
(Normally, 1 times per day as a sequence control) and optimum control technique.
吹灰器以一定间隔自动运转（通常是一天顺次运行1次）并且要能够方便地操作。
The soot blowing system include all necessary blowers, electric drive motors, all piping
including drain system, instrumentation, valves, control valves, safety valves, hose, electrical accessories, relays, support frames, hangers, supports and all other required components for operation.
烟气吹扫系统包括必要的鼓风机、电动机、所有管道；包括排放系统、仪表、阀、控制阀、安全阀、软管、电气附件、继电器、支撑框架、吊架、支架和运行其他相关的所有其他组件。
3) Duct and Flue gas control device 烟道和烟气控制装置
- Ductwork
烟道系统
Necessary flue gas ductwork, supports and hangers, gas distribution devices, test ports, instrument connections, expansion joints, gaskets/bolting materials, and access facilities are supplied.
供应烟气管道系统，支撑和吊架，气流分布装置，测试口，仪器连接，膨胀节，法兰垫圈/螺栓连接材料和通道设备。
SCR 도면 참조 – 도면 1
3.2.2 NH3 Storage and Handling System 氨的存储和处理系统
The ammonia storage and handling system unload and store the an hydrous ammonia
(99.6% or more) as SCR agent. This system consist of two (2) unloading compressor, two(2)
ammonia storage tanks, one waste ammonia dilution tank, ammonia leakage detection and
alarm system, water spray system, safety system, associated piping, fittings, supports, valves and accessories.
氨的存储和处理系统用于卸载并存储无水氨（纯度为99.6%或更高），作为SCR的反应剂。此系统由两台卸料压缩机、两个储氨罐、一个废氨稀释槽、氨气泄漏检测器和报警系统、水喷淋系统、安全系统及相应的管道、管件、支架、阀门，附件及附件组成。
The anhydrous ammonia is stored under a high pressure and accidental atmospheric release of anhydrous ammonia vapor can be hazardous; therefore safety and environmental protection is required.
无水液氨在高压条件下储存，液氨的意外泄漏将招来大危险；因此必须配备安全装置，以保护周边设施。
Liquid ammonia is transferred from tank lorry to the ammonia storage tank by unloading compressor. Ammonia in the storage tank is transferred to the vaporizer by self pressure.
液氨通过卸料压缩机从槽车输送到储氨罐中。液氨由储罐中靠本身的压力输送到蒸发槽中。
암모니아 도면 참조 -2
1) NH3 Storage Tank (Owner Scope) 储氨罐(业主范围)
The net working volume of each ammonia storage tank shall have both minimum 79㎥(at 22.2kg/㎠, 55℃) and 10 days(20hrs/day) storage based on the maximum design anhydrous ammonia flow required to meet SCR system operation per unit at BMCR flue gas conditions.
A vapor space of minimum 15% of the total tank capacity shall be provided at the top of the tank.
每个储氨罐的实际储存容量为79㎥(22.2 kg/㎠, 55 ℃)，并且锅炉BMCR工况下纯氨的消耗量可以满足10天(20小时/天)的用量。储氨罐的上部至少留有全部容量的15%的汽化空间。
For each ammonia storage tank, filling connection shall be provided with a combination of back pressure check valve and excess flow valve to prevent massive ammonia leakage in the event of a catastrophic line break.
每个储氨罐的连接处都要有背压止回阀和流量限制阀，防止当管道遭破坏时大量氨的泄漏。
Each tank shall be equipped with the following equipment as a minimum:
每个罐至少应该安装以下的装置：
- One(1) 600mm or larger diameter manhole at the top of tank.
在罐的顶部有一个600毫米或更大直径的人孔门
- The local gauges, transmitters, and switches with isolation valves located on each tank.
安装于每个罐的仪表，变送器和开关带有绝缘阀
- Two(2) safety relief valves shall be sized with a capacity such that either valve can protect the tank. The safety relief valve design must be capable of permitting maintenance and removal without draining the tank.
两个安全溢流阀应该按能保护罐的容量制作。这个安全溢流阀的设计必须能够允许不排干罐也能维持和移动。
- Level transmitters to automatically turn off the unloading compressors to prevent ammonia from exceeding the highest or maximum permissible level. The maximum permissible liquid anhydrous ammonia level shall not exceed 85% of the tank's total capacity.
水平变送器自动地关闭卸料压缩机以阻止氨超过最高或可允许的最大高度值。液氨水平面达到最高时其体积应不超过罐总容量的85%。
- An ammonia flow meter with totalizer and automatic temperature compensator installed at the inlet of each ammonia storage tank.
在每个氨存储罐的入口处安装一个带有累加器和自动温度补偿的氨流量计。
- An ammonia leakage sensor and alarm located near the tank area.
在罐附近安装一个氨泄露传感器和报警器。
- Metal roof sunshade above the storage tank shall be installed for preventing from the sun shines.
储罐上面装有金属屋顶的遮光罩。
A water spray system shall be activated when leaked ammonia is detected or the internal pressure(or temperature) for cooling the tank and controlling the vapor pressure(or temperature) inside the storage tank.
有一套喷水系统，用于冷却罐体及控制储罐内部的蒸发压力(或温度)，当内部的压力(或温度)超过设定值时，喷水系统将自动开启，且开始喷水。
2) NH3 Unloading Compressor(Owner Scope) NH3卸料压缩机（业主范围）
Two(2) 100% ammonia unloading compressors with electric motors shall be furnished to transfer liquid anhydrous ammonia from the delivery tank lorry to the ammonia storage tanks. The compressors, ammonia unloading local control panel and unloading bulkhead shall be furnished and designed for installation in the vicinity of the tanks.
2个100%卸料压缩机装有电动机，用来将液氨从罐车传送到存储罐。存储罐附近应装有压缩机，卸料控制盘和卸料管母接头。
The compressor shall have pressure gauges at the suction and discharge lines.
The piping shall contain shutoff valves located as close as practical to compressor quick
connections.
在压缩机抽吸器和排出管道处要安装压力计。在靠近压缩机快速连接装置的地方要安装截止阀。
A shutoff valve shall be provided for enabling automatic/manual shut off of ammonia feeding from ammonia tank lorry to the storage tanks in case of emergency.
在紧急情况下，截止阀可以自动或手动切断由罐车到储存罐的液氨供给。
3) Waste Ammonia Treatment System 废氨处理系统
- Dilution Tank
稀释槽
A waste ammonia dilution system are provided to dilute the vented and leaked ammonia gas from the equipment located within the battery limits. Diluted water in the tank is replaced periodically, i.e drained into ammonia sump.
废氨稀释系统把位于界区内的设备排出和泄漏的氨气进行稀释。罐中的稀释水周期性地更换，排到氨贮槽中。
DIlutaion 도면 참조 - 3
- Wastewater sump and sump pump
废水池和废水泵
The waste water sump and submergible pumps are designed to transfer waste water from NH3 Storage and handling system to designated disposal point.
废水池和能沉入水中的泵能将废水从氨储罐和处理系统传输到已设计的处理处。
3.2.3. NH3 Injection System 氨注入系统
The Ammonia injection system is designed to vaporize, dilute and inject the anhydrous
ammonia as NOx reduction reagent.
This system consist of vaporizers & accumulators,
dilution air blowers, ammonia control valves, ammonia/air mixer, ammonia injection grids,
associating piping, fittings, supports and valves.
Liquid ammonia from the ammonia storage tank is transferred to the vaporizer by self-pressure, and then vaporized in the vaporizer using auxiliary steam as the heating source.
Concentrated anhydrous ammonia vapor is diluted with dilution air so than the ammonia/air mixture is safe to handle and non-flammable.
The ammonia/air mixture is injected through the ammonia injection grid located in the SCR reactor inlet duct.
氨注入系统的设计方法是蒸发、稀释和注入作为脱硝剂的无水液氨。此系统包括液氨蒸发槽和氨气积压器、稀释风机、氨控制阀、氨/空气混合器，注氨格栅，以及相应阀门、管道及其附件、支撑组成。液氨靠自身的压力从储氨罐输送到蒸发槽，液氨在蒸发槽中被辅助蒸汽加热蒸发。浓缩的氨气被空气稀释后，确保安全操作并且不具有可燃性。稀释后的氨气通过安装在SCR反应器入口烟道的注氨格栅注入。
1) NH3 Vaporizer and Accumulator 氨蒸发槽和缓冲槽
The vaporizer assembly are designed to be installed in a natural transfer loop where ammonia flows by the self pressure, taking liquid ammonia from the bottom of the storage tank and transferring the vaporized ammonia to the accumulator. All piping connection shall be fully welded. Threaded connections are not acceptable. All piping welds in this loop shall be stress relieved.
蒸发槽装置设计安装在正常的氨靠自身压力流动的传输回路，从储罐的底部获得液氨并把蒸汽氨输送到缓冲槽。所有的管道联接应该是满焊。螺栓联接是不允许的。在这个回路中所有的管道焊接应该消除应力。
The Steam traps, temperature controllers, steam control valves with accessories and low-high temperature alarms required for ammonia temperature control, thermometers, pressure indicator, level indicator, etc. are provided for the vaporizer.
蒸发槽提供汽水分离器、温度控制器、带附件的蒸汽控制阀和氨温度控制所必需的低-高温度报警器、温度计、压力指示器、料位计等。
A thermostat controller shall be located within each vaporizer to prevent overheating of the vaporized ammonia.
温度调节控制器位于每个蒸发槽内部，防止蒸汽氨温度过高。
Safety valves for vaporizer and accumulator shall be provided and its discharge is forwarded to the waste ammonia dilution tank.
蒸发槽和缓冲槽应该提供安全阀，并且它的排出物排向废氨稀释罐。
Vaporizer and Accumulator 도면 참조 – 4, 5
2) NH3 Dilution System 氨稀释系统
An ammonia dilution system located near the ammonia injection grid are provided. The system include the following equipment:
氨稀释系统位于提供的注氨格栅附近。这个系统包括下面的设备：
- Ammonia flow control, and shut-off valves
氨流量控制和关闭阀
- Two(100%×2/unit) dilution air blowers
两台（100%X2/台）稀释风机
- Local skid with piping and instrumentation
管道和使用仪器用的安装导轨
- Two(2) ammonia/air mixers per unit
每台两台氨/空气混合器
- Dilution Air Blower 도면 참조 - 6
稀释风机
- NH3 /Air Mixer 도면 참조 - 7
氨/空气混合器
The ammonia/air mixer shall meet requirements regarding safety in handling the air and ammonia mixture. The mixer will be designed to ensure a homogeneous ammonia/air mixture to each ammonia injection inlet manifold.
关于安全方面在处理空气和氨混合时氨/空气混合器必须满足要求。混合器的设计是为确保每台氨注入系统入口多叉管处氨和空气能够均匀的混合。
- Ammonia Injection Grid 도면 참조 - 8
注氨格栅
The ammonia injection grid, shutoff valve and ammonia flow control valves for ammonia
Injection flow control are provided. The ammonia flow control valves is sized for the full range of ammonia flows.
包括截止阀和用于控制喷射流量的控制阀。控制阀型号根据氨流量的满量程确定。
3.2.4. Safety Equipment and N2 Gas Purging System 安全设备和氮气吹扫系统
1) Safety equipment
安全设备
An eyewash and safety shower station in close proximity to the NH3 Storage area is supplied. The complete eye washer/shower set shall be self-standing type. It is able to operate separately by foot and hand.
Additional safety equipment such as a face masks , gloves, boots, etc. will be provided with a cabinet. The safety equipment will satisfy Korean or China local government requirements.
氨存储罐区域附近要安装淋浴和安全喷淋设备。这些设备随时可以使用，并可以分别用手和脚操作。
还有附加的安全设施，例如面罩、手套、靴子等，将其放到橱柜里。安全设施要符合韩国或中国当地的规定。
2) N2 Gas Purge System
氮气吹扫系统
Nitrogen purging system to purge out all unused a ammonia from the ammonia-containing equipment and piping are required when the equipment is not in service for extended period.
N2 Gas has to be supplied from an exist N2 Storage facilities to satisfy according to the design condition.
当存有氨的设备或管道在一段时期内不使用时氮气吹扫系统可以将氨清除。根据设计要求，氮气储存在专用的氮气存储装置中。
3.3 Operation procedure for SCR System SCR系统的运行程序
3.3.1 General Operation Manual for SCR System SCR系统的一般运行手册
1) Check Point 校核点
The following item shall be check before system operation.
系统运行之前为了确认如下事项:
(1) Check for Power supply 确认电源供给
- Panel 各种控制柜
- Instruments 各种仪表
(2) Check for supply condition for Instrument & service air
确认仪表和补助空气供给条件
- Temperature : 50℃ or less 温度 :50℃以下
- Pressure : 6.0 Kg/cm2 or above 压力 : 6.0 Kg/cm2 以上
- Due point : -3.0℃ or less 露点温度 :-3.0℃以下
(3) Check for auxiliary steam . 确认补助蒸汽
- SCR soot blower line : 8Kg/cm2, 320℃ SCR吹灰器管线：8Kg/cm2, 320℃
- NH3 Vaporizer : 5Kg/cm2, 183℃ 氨蒸发槽： 5Kg/cm2, 183℃
(4) Check for Operation of Dilution Air blower 确认稀释风机的运行
2) Operation procedure for SCR System SCR系统的运行程序
After system check, SCR System shall be operated as following procedure.
系统确认完毕后，SCR系统按如下步骤运行:
(1) Start procedure for SCR Reactor and Auxiliary system.
SCR反应器及补助系统的启动步骤
a. Normal Start 正常启动
start –up the boiler catalyst should be heated from cold
启动锅炉 conditions with warm air above the
water dew point of the flue gas
to avoid condensation of water at cold
start-up Flue Gas draft system start of the unit
启动通风系统 用烟气露点温度以上的暖空气预热冷态
催化剂，以避免系统冷态启动时出现冷
凝水
start Dilution Air Blower,
Seal Air system of soot blower and
protection air system
启动吹灰器的密封系统(稀释风机)，
以保护空气系统
- warm-up SCR 预热SCR
check boiler fluegas rising * Rising temp. shall be under 100℃/min
temperature for SCR catalyst 温升应小于100℃/min
校核锅炉烟气在SCR催化剂上的温升
start-up soot blower operation * stand-by soot blower operation
after fluegas temperature at down 等待吹灰器运行
stream of SCR reactor is above
250℃
SCR反应器下游的烟气温度超过
250℃启动吹灰器运行
soot blower Shut-down
After 1 Cycle operation
Fluegas temperature after SCR 吹灰器运行1个循环后停止
De-NOx reactor is above Minimum
Operating Temperature
SCR反应器出口的烟气温度超过
最低运行温度
Start NH3 Injection Stand-by NH3 supply system
开始注氨 NH3供应系统等待运行
SCR system is place in operation
SCR系统运行
(2) Shutdown procedure for SCR Reactor and Auxiliary system.
催化剂反应器及补助系统的停止运行程序
a. Normal shutdown for catalyst
反应器的正常停止
Shut off boiler burner
锅炉燃烧器停止点火
Stop NH3 Injection When the flue gas
temperature can not be maintained
Minimum operating temperature
当烟气温度不能维持在最低运行温度
时，将停止氨的注入。
* stand-by soot blower operation
吹灰器等待运行
Start soot blower of SCR
SCR吹灰器启动
Soot blowing before flue gas
temperature at downstream of
SCR reactor is going down 250℃
When the soot blowing is finished SCR反应器下游烟气温度小于
normally the function Group of DeNOx 250℃之前
is placed at “standstill”
当吹灰完成正常的运行后，
脱硝系统应位于 “停止”状态
Purging and Cooling down of
the boiler and the catalyst
冷却锅炉和催化剂
Shut off Dilution Air Blower,
Seal Air System of soot blower
And protection air system
停止稀释风机；停止吹灰器的密封
系统和保护空气系统
Flue Gas Draft System off
通风系统停止运行
b. shutdown for weekend standstill (<72 hrs) 周末的停止运行(<72小时)
shut off boiler burner
停止锅炉燃烧器
Start soot blower of SCR same as procedure of
“Normal shut-down”
SCR吹灰器按“正常停止”程序停止
When the soot blowing is finished, normally the function
Group of De NOx is placed at “standstill”
当吹灰完成正常的运行后，脱硝系统应位于 “停止”状态
Flue Gas Draft System off
通风系统停止运行
– Operation Procedure for Ammonia Unloading and Storage system
氨的卸料及储存系统的运行程序
* Engine Stop 关掉槽车发动机
Tank lorry Park and Stop * Earth Connection 连接接地线
氨槽车停在指定位置
Connection with HOSE
连接软管
* Check for Flow meter a valve open
Start up Unloading compressor 确认流量表阀门打开
启动卸料压缩机 * Check for Pressure gauge
确认压力表
* Check for Tank level indicator
确认储氨罐的液位显示仪
Stop up Unloading compressor * Check for Valve close 确认阀门关闭
关闭卸料压缩机 * N2 gas Purge N2气净化
Disconnection with HOSE
解开连接软管
* Engine Start 开动槽车
Start up Tank lorry * Earth disconnection 解开接地线
从停车位置发车
– Operation procedure for Safety system 安全系统运行程序
– Dilution Tank System 稀释槽
* Check for level of Dilution Tank
确认稀释槽的液位
Generation for Waste Gas * Check for Valve Open /Close
各工艺系统产生的废气 确认阀门开/闭
* Sump pump operation while drain of
Dilution Tank
稀释槽排放时启动废水泵
- Water Spray System 喷淋水系统
Emergency Condition “Leakage NH3 Gas, *.Check for Shut off Valve (确认紧急关闭阀)
Abnormal condition for Ammonia Storage Tank * Check for Pressure Gauge (确认压力表)
当出现紧急情况(氨气泄漏，储氨罐压力异常) * Check for Water line (确认供水连接阀门)
End of Emergency condition * Check for sump pump operation
紧急情况 确认废水泵启动
* Check for Water line (确认供水管线)
- N2 Gas Purge system 氮气净化装置
* Check for N2 Gas Bomb 确认氮气罐
N2 Gas Purge start * Check for level of Dilution Tank
开始氮气净化 确认稀释槽液位
* Check for Valve Open/Close
确认阀门开/闭
N2 Gas Purge Stop * Check for Level of Dilution Tank
停止氮气净化 确认稀释槽液位
* Check for Valve Open/Close
确认阀门开/闭
– Operation procedure for Ammonia Supply and Injection System
氨的供给及注入系统的运行程序
* Check for Lever Indicator 确认液位仪
Loading Tank Selection * Check for Valve Open 确认阀门打开
* Check for Pressure 确认压力
* Check for Water Temp. in Vaporizer
Start Vaporizer 确认蒸发槽内部水温
启动蒸发槽 * Check for Valve Open 确认阀门打开
* Check for Steam Supply Valve Open
确认蒸汽供应阀门打开
Start Accumulator
启动缓冲槽 * Check for Pressure 确认压力表
* Check for Temperature 确认温度计
* Check for Valve Open 确认阀门打开
Check PCV
确认PCV * Check for Pressure 确认压力
Check Dilution Air Blower’s
Operation
确认稀释风机启动
NH3/Air mixer
NH3/Air 混合器
Ammonia Injection Grid * Check for Flow Indicator 确认流量指示仪
注氨格栅
3.3.2 SCR Reactor System SCR反应器系统
1) SCR Reactor and Catalyst Operation SCR反应器和催化剂运行
- Start-Up, Cold Start
启动，冷启动
At cold start of the unit, the DeNOx unit should be preheated by warm air. The catalyst shall be preheated to a temperature above the water dew point of the flue gas to avoid condensation of water in the catalyst during the start-up. Incomplete combustion of fuel oil during start-up may cause formation and deposition on the catalyst of soot. This implies a risk of partial plugging of the pore system in the catalyst and consequently deactivation. Later oxidation on the catalyst of unburned components may also cause local overheating.
在冷启动的时候，脱硝装置应该先由暖空气预热。催化剂应被预热至烟气露点以上，以避免启动时催化剂出现结露。燃料油的不完全燃烧会导致催化剂底部的沉积，产生阻塞孔隙的危害，从而降低活性。催化剂上的未完全燃烧成分的氧化，会导致局部过热的现象。
-Restart
重新启动
After a shutdown of the reactor, re-start may be done without any preheating of the catalyst if the reactor temperature is still above the water dew point of the gas. Otherwise, the procedure described above in “Cold Start” must be followed.
在反应器停机后，如果反应器的温度仍然在烟气露点以上，则无需预热催化剂就可进行重新启动。否则，按照冷启动的步骤进行启动。
-Start of NH3 Injection
氨气喷注系统的启动
The NH3 injection can be generally started when the exit temperature from the DeNOx catalyst is 10ºC above the ammonium bisulphate (ABS) dew point (see the section
- Limitations in Operating Temperature below).
当催化剂反应器出口温度高于硫酸氢氨露点温度10oC时，氨气注入系统可以启动 (参照以下运行温度的限制)。
2) Normal Operation
正常操作
-Catalyst Operating Temperatures
催化剂运行温度
The DNX catalyst is very resistant to thermal shocks and it is able to tolerate the temperature changes which are normal to the boiler, i.e. the catalyst is not a limiting component during start-up, load changes, and shutdown.
DNX催化剂有良好的抗热冲击的性能，并且可以承受锅炉正常温度的变化，催化剂的运行不会受到锅炉启动，负荷变化，以及停转的影响。
Without sulphur compounds present in the flue gas stream, the normal operating temperature for DNX catalyst is 220 – 450ºC. At low temperature the catalyst activity is, of course, low but as this normally occurs at low boiler loads it will not induce any decrease in NOx removal efficiency. At high temperatures catalyst sintering will be more pronounced. At extremely high temperatures (> 450ºC), this could result in damage to the catalyst and deteriorated NOx removal.
烟气中不含有硫的情况下，DNX催化剂的正常运行温度为220-450oC。温度低的条件下，活化性能就低，但低温一般发生在低的锅炉负荷情况下，此时将不会降低脱硝效率。在高温的情况下，将出现催化剂的烧结现象。当温度大于450oC时，将导致催化剂的损毁，从而降低脱硝效率。
- Design operation temperature are 设计运行温度
Minimum (lower) continuous operating temperature : 317 oC
Maximum(upper) continuous operating temperature : 420 oC
持续运行最低温度：317 oC
持续运行最高温度：420 oC
- Limitations in Operating Temperature
运行温度的限制
To avoid temporary deactivation of the catalyst caused by deposition of ammonium bisulphate (ABS) formed from reaction of ammonia with SO3, the inlet temperature for continuous operation should be above the dew point of ABS. The dew point depends on the concentrations of SO3 and ammonia and hence on the NOx inlet level and the intentional DeNOx efficiency.
为了避免由于硫酸氢氨（ABS）沉积引起的催化剂暂时失活，连续运行时入口处温度应高于硫酸氢氨的露点温度。露点温度由氨气和SO3的浓度决定，以及入口处NOx的浓度和脱硝效率。
Figure 2.1 shows typical minimum continuous operating temperature for prevention of ABS condensation.
图2.1中表示了防止ASB沉积的最低连续反应温度。
ABS condensation will occur first in the pores of the catalyst. The condensation process is reversible and raising the operating temperature back above the dew point will cause the ABS to evaporate and the catalyst activity will be restored.
ASB的沉积将首先发生在催化剂的空隙里。沉积的过程是可逆的，当运行温度提升到露点以上ASB将蒸发，催化剂活性将恢复。
Only in the case of long time operation below the dew point temperature, the catalyst activity may be affected permanently. ABS deposits are usually somewhat sticky and can cause some adhesion of fly ash. It is therefore recommended to increase the soot blowing frequency during periods of operation below the ABS dew point temperature.
只有当长期在低于露点的温度下运行时，催化剂活性会被永久地改变。硫酸氢氨的沉积会产生粘性，粘住飞灰。当长时间在露点以下运行时，建议增加吹灰的频率。
The condensation in the catalyst pore system will occur at higher temperature than for condensation in the bulk phase (capillary condensation) and the temperature depends on the pore size. The bulk condensation temperature is approximately 35ºC lower than the minimum temperature in Figure 2.1
在催化剂孔隙中发生凝聚时的温度高于在毛细管中发生凝聚的温度，凝聚温度取决于孔隙的大小。在毛细管中发生凝聚的温度大约比图2.1中的最低温度低35oC。
Since the catalyst contains pores of different sizes and there is an ammonia and SO3-profile in the catalyst, ABS condensation actually takes place over a range of temperature.
由于催化剂包含有不同大小的孔隙，以及三氧化硫和氨气的存在比例，硫酸氢氨的凝聚实际发生在一定的温度范围内。
The concentration profiles of NH3 and SO3 in the catalyst depends on the catalyst activity and it takes a long time before the steady-state equilibrium between ABS condensation, concentration profiles, and remaining catalyst activity is established.
催化剂中氨气和三氧化硫的浓度取决于催化剂的活性。硫酸氢氨的凝聚，浓度比例，催化剂的稳定活性的平衡的建立需要一段较长的时间。
At operating temperatures between the temperature for pore condensation and the bulk condensation temperature, only a fraction of the catalyst pores become filled with ABS. The steady-state residual activity hence depends on the temperature.
当运行温度在孔隙凝聚温度和分散凝聚温度之间时，只有小部分催化剂孔隙被硫酸氢氨堵塞，稳定状态的活性取决于温度。
At an operating temperature below the bulk condensation temperature the steady-state activity is zero.
当运行温度在分散凝聚温度以下时，稳定状态的活性为零。
Long-time operation at temperatures considerably below the ABS condensation temperature will lead to a significant reduction in catalyst activity. In such cases it may not be possible to fully restore the activity by bringing back the temperature to values above the dew point.
运行温度长期低于硫酸氢氨凝聚温度时将导致催化剂活性的明显降低。这种情况下，即使将温度升至露点以上也不能完全恢复活性。
The time for uninterrupted operation below the ABS dew point without full regeneration must therefore be restricted to 300 hours and the temperature must be kept above 270ºC in any point of the catalyst layers.
在低于ABS 露点温度的条件下连续运行的时间必须控制在300小时以内，同时每层催化剂各点的温度必须在270oC以上。
Figure 2.1 shows the minimum operating temperature for prevention of ABS condensation for a typical coal fired power plant.
图2.1表示，在燃煤锅炉中防止硫酸氢氨凝聚的最低运行温度。
Figure 2.1 Minimum SCR inlet temperature depending on SO3 concentration (typical only)
图2.1 依据SO3浓度，SCR入口处最低温度
Figure 2.1 Minimum SCR Reactor Inlet Temperature
图2.1 SCR反应器入口最低温度
- Load Changes
负荷变化
The catalyst is resistant towards temperature changes and is able to accept variations corresponding to normal load changes of the boiler. DNX catalyst can tolerate temperature changes of more than 100ºC per minute.
催化剂可以抵抗温度变化，以及由各种原因引起的锅炉负荷变化。DNX催化剂可以承受每分钟100oC的变化。
3) Soot blower Operation 吹灰器的运行
Soot Blowing system which is Retractable type is to install for purpose of dust removal on the Guide Vane in SCR Inlet duct, and to used for prevent dust accumulation on Catalyst layer.
吹灰设备有两种；一种是除去沉积在反应器入口导向板灰尘的手动用吹灰器，另一种是防止和除掉SCR反应器的粉尘等异物的4套往复运动形式的吹灰器。
Blowing medium is used as superheated steam , it shall be operated to Min 250℃, 5kg/cm2 .
吹灰器的媒体为最少温度250℃和5kg/cm2以上的过热蒸汽，只有满足这两个条件时才能进行吹灰。
Steam Condition for Soot Blower :
吹灰器蒸汽的最低条件:
- steam pressure: Min. 5kg/cm2 蒸汽压力: 最小5kg/cm2
- steam Temperature: Min.250℃ 蒸汽温度: 最小250℃
Supplied steam shall be operated to Soot blowing in case of meeting above condition.
用于吹灰的蒸汽只有符合以上的最低条件时，才能进行吹灰。 |
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发表于 2007-8-20 17:55:33
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