锅炉水压试验作业指导书
本作业指导书仅用于糖厂电站锅炉,对锅炉整体水压试验规定了施工程序和做法,在施工时必须按此作业指导书实施。
一、概况
锅炉受热面系统安装完后,应按DL/T5047-95《电力建设施工及验收技术规范》(锅炉篇)及锅炉设计技术文件的规定进行水压试验。锅炉水压试压范围包括:从省煤器进口联箱前截止阀(图275B81-0给水操纵台)到高温过热器出口联箱主蒸汽出口阀门处。包括省煤器、水冷壁、过热器以及锅炉本体范围内的排污、疏放水、取样、放空、锅炉加药、减温水等系统的全部管道。
其中
1) 水压试验时安全阀按照制造厂要求(技术要求)采取措施或采用堵板进行隔离。
2) 锅炉蒸汽吹灰及管道一次阀以前参加水压试验。
3) 水压范围内的热工测点、水位、压力取样一次阀前参加水压试验。
二 编制依据
2.1 DL/T5047-95《电力建设施工及验收技术规范》(锅炉篇、管道篇、电厂化学篇、焊接篇)
2.2锅炉制造厂家提供的锅炉设计图纸
2.3锅炉制造厂家提供的《锅炉安装说明书》(275B-SM7)、《锅炉说明书》(275B-SM1)
三 施工准备
3.1施工所需机械\材料准备
3.2人力准备
3.3施工技术准备
1)主管技术人员熟悉施工图纸及相关规范、设备参数。
2)主管技术人员召集施工人员进行施工技术交底。
四 质量要求: 合格(压力升至试验压力,保持5min后降至工作压力进行全面检查,检查期间压力应保持不变;检查中无破裂、变形及漏水现象)
五 施工工艺
5.1水压试验技术要求如下
5.1.1水压试验时,部件的壁温应保持在20℃~50℃,如果水温不能满足上述要求,应采用临时设备加热的方法来加以保证(本工程锅炉水压试验地处热带气候,水温可达到上述要求);
5.1.2根据DL/T5047-95《电力建设施工及验收技术规范》(锅炉篇),锅炉最大允许工作压力为6.0MPa,整体水压试验压力为6.0*1.25=7.5MPa。故选用量程为0~16MPa,压力表制造精度为1.5级,D=200~250mm,经过校核合格的压力表2块。布置位置:过热器出口联箱。
5.1.3考虑升压过程中监视方便,在升压泵出口管道上,锅炉零米,升压泵附近设置一块量程为0~16MPa精度为1.5级,D=200~250mm,经校验合格的压力表1块。
5.1.4水压试验的水质应使用清洁的水源,最好使用合格的锅炉给水要求的水质(电导率≤0.3μs/cm PH=9.0~9.5 溶氧≤7μg/l 硬度≤1.0μmol/l)。
5.1.5水压试验应具备条件
5.1.5.1钢结构安装完毕并报验验收,经工程师验收签证;
5.1.5.2锅炉本体受热面和承压部件按图纸要求全部安装完毕;
5.1.5.3受热面部件间的所有连接管安装完毕以及炉本体疏水、排汽、排空、取样、分离器附属系统、减温水、吹灰管等安装至试验要求范围之内;
5.1.5.4凡和受压部件焊接并在水压试验范围内受热面上的门孔密封件,保留钩钉,防磨防震罩或板,所有热工测点、刚性梁、一次密封应全部施焊完毕,并经验收;
5.1.5.5所有焊在受压部件上的临时铁件均应割除打磨光滑,母材无损伤;
5.1.5.6所有需临时封堵的部件(如安全阀、主蒸汽出口管道),堵板应满足强度要求;
5.1.5.7按图纸要求,锅炉所有膨胀部位应检查合格,满足锅炉膨胀要求,膨胀指示器相应安装焊接施工完成;
5.1.5.8承压部件焊口全部结束,并经检验合格;
5.1.5.9水压试验用的通道楼梯、平台、栏杆和临时脚手架应安全畅通,保证有足够的照明,如锅炉内外应清扫干净无垃圾;
5.1.5.10水压试验用临时供水系统安装调试完毕;
5.1.5.11保证水压试验期间,试验现场通讯畅通,对讲机设置专用频道,便于及时通讯;
5.2水压试验程序
5.2.1锅炉水系统和过热系统的注水
5.2.1.1开启水冷壁下联箱疏水门;
5.2.1.2打开系统的排气阀,其他阀门关闭。
5.2.1.3开注水泵及出口阀向锅炉注水
5.2.1.4每个系统的排气门有水溢出时,返复开关3-5次,确保没有空气停留在系统内。关闭排气阀。停止锅炉向系统注水。
5.2.2试压
5.2.2.1给试压用临时水箱注满水,开启试压水泵出口阀及泵出口再循环管路阀,开启水冷壁下联箱疏水阀,开始向系统升压;
5.2.2.2用升压泵再循环门来调节升压速度,控制在0.3MPa/分钟之内,升压泵出口处的压力表和炉顶过热器出口联箱的压力表要有人严密监视,观察压力的变化,并保持与试压总指挥及时的联系;
5.2.2.3当压力升至试验压力的10%,即0.75Mpa时,关闭升压泵出口阀及旁路阀,对受压力试验的所有系统进行全面检查,检查有无压力降低、系统有无泄露、裂纹、变形与破损,根据检查结果由试压总指挥、现场工程师决定是否继续升压;
5.2.2.4当压力升至工作压力6.0Mpa时,停泵全面检查系统,检查有无压力降低、系统有无泄露、裂纹、变形与破损,记录检查结果,及检查过程中压降情况;
5.2.2.5调节升压速度,保持一个较低的速度继续升压。升压至7.5Mpa的试验压力,关闭泵出口阀及旁路阀,停泵保持5分钟; 停泵期间,应注意观察压力表读数变化情况,经业主、监理等确认后,开始降压。微开旁路阀,降压至工作压力 (降压速度在0.3MPa/分钟之内),再次仔细全面检查各系统,有无渗漏,这期间保持系统压力 。记录好每处检查到的缺陷,作好记录表;
5.2.2.6微开试压泵再循门,系统逐渐降压,降压至过热器出口联箱就地压力表读数为零时,完全打开疏水阀,打开炉顶空气阀、放水,系统水压试验结束。
六、水压试验人员组织形式
总指挥1人
技术负责人1人(现场工程师)
泵操作员2人 电工2人
炉顶抄表员1人 (监视水压压力并对水压过程进行记录)
阀门操作人员4人
后炉膛检查人员10人
前炉膛检查人员6人
七、临时供水系统
从水源处接入一根φ159临时供水管,至临时水箱。上水泵出口管接至锅炉给水操纵台入口阀门。如图:
八、 安全施工
8.1遵循项目安全规定。
8.2本作业的特殊规定:
a、水压前应将水压系统设备、阀门作一次全面检查,升压时作业区要挂牌,隔离非本项工作人员进入。水压试验时严禁非工作人员进入水压试验范围。锅炉水压期间,炉本体区域不得有人施工,所有人员离开后方可升压。
b、水压试验时锅炉上应停止一切无关作业,并严禁在承压管道和设备上动用电火焊或敲打。在升压过程中,巡视检查受热面膨胀情况,如若发现异常,应查明原因,处理后方可继续升压。
c、升压泵、上水泵及系统各阀门应有专人负责,注意泵的运行及维护;水压泵在水压前必须试转确认可靠。阀门操作点,检查焊口处应有牢固脚手架,道路平整,并有足够的临时照明。
d、在升压时升压泵与炉顶就地压力表处应有可靠的联络,以防系统超过试验压力。
e、监视压力表、升压泵及操作阀门的人员应考虑好安全退让路线,超压时,严禁巡回检查,人不能站在临时堵板、焊口、水位计接口对面和法兰结合面处,参加水压试验和检查人员,不得单独行动,检查时应有人监护,各阶段检查结束后小组负责人应清点小组人数和所带工具。
f、凡参加水压试验和检查人员必须服从指挥,分工明确,职责到人,并应熟悉系统。
g、水压检查时,如有异常情况应及时向指挥组汇报,不得自行处理。在各阶段检查时检查人员按组件划分,并认真做好检查记录。
h、水压试验时设置专职救护人员及车辆,预防意外事故发生。
Method Statement of Hydraulic Test on Boiler (Rev 061104)
This statement applies to boilers construction of SSMP, stating the testing procedures and methods to be used for the overall hydraulic test of the boilers. Throughout the hydraulic test, this method statement should be executed strictly.
1 Brief Introduction
After the installation of boiler heating surface system, hydraulic test should be carried out as required in the DL/T5047-95 The Code of Erection and Acceptance of Electric Power Construction (boiler section), and relative boiler design documents. Hydraulic test will be carried out from the front stop valve in the economizer inlet header (water feeding operation table in Drawing 275B81-0) to the main steam outlet valve in the header of superheater, the scope including economizer, water cooling wall, superheater, and all the boiler body pipe systems of sewage drainage, water discharge, sampling, air exhausting, Na3PO4 solution treatment, and desuperheater cooling water service.
Among which:
1.1 While test, the safety valves will be isolated by stop plate or other measures against the manufacturer requirements (technical requirements).
1.2 The area before the first valves in the boiler steam blowing system and pipes locates in the hydraulic test scope;
1.3 The area before the first valves in thermal-engineering measurement point, water level sampling system, and pressure sampling system locates in the hydraulic test scope.
2 Compilation References
2.1 DL/T5047-95 The Code of Erection and Acceptance of Electric Power Construction (boiler section, pipe section, power plant chemical section, welding section)
2.2 Boiler design drawings provided by boiler manufacturer
2.3 Boiler Erection Instruction (275B-SM7), Boiler Instruction (275B-SM1) provided by the boiler manufacturer
3 Construction Preparation
3.1 Tools, equipment and Materials Preparation
3.2 Workforce Preparation
3.3 Technical Preparation
3.3.1 The principal technicians will study the construction drawings, relevant construction Codes and equipment parameters.
3.3.2 The principal technicians will carry out the technical instruction for the persons to participate in this test.
4 Quality Requirement: Up to Standard
(Boost the pressure to the required test pressure, keep this condition for 5 minutes, and then reduce the pressure to normal operation pressure and carry out overall inspection, no burst, deformation or water leakage occurs)
5 Construction Procedure
5.1 Technical requirements of hydraulic test are as follows:
5.1.1 During the hydraulic test, components’ wall temperature should keep within 20℃~50℃,if the inside water temperature can’t meet this temperature requirement, temporary heating method should be carried out to meet this requirement (This project locates in the tropical climate area, so the water temperature in this hydraulic test definitely can meet the requirements.)
5.1.2 According to the DL/T5047-95 The Code of Erection and Acceptance of Electric Power Construction (boiler section), boiler’s maximum operation pressure is 6.0Mpa, and the overall hydraulic test pressure is 6.0*1.25=7.5Mpa. So we will distribute two calibrated pressure gauges with a measurement range of 0~16Mpa, the fabrication precision degree of Class 1.5, D=200~250mm, in the superheater outlet header.
5.1.3 For the convenience of observing while boosting the pressure, install a pressure gauge on the pressure boosting pump’s outlet pipe, at the boiler elevation of +0.000mm. A calibrated pressure gauge, with the measurement range of 0~16Mpa, the fabrication precision degree of Class 1.5, D=200~250mm, will be distributed near the pressure boosting pump.
5.1.4 Water to be used in the hydraulic test shall be clean water, best with the qualified water quality required for boiler water supply. (electricity conductivity≤0.3μs/cm PH=9.0~9.5, oxygen content≤7μg/l, hardness≤1.0μmol/l)
5.1.5 Preconditions for the hydraulic test
5.1.5.1 Structural steelwork erection work shall have been completed, and the test release form have been approved and signed by the BTL Engineer.
5.1.5.2 Heating surface and pressure parts of the boiler body are all installed against the Drawings.
5.1.5.3 All the connection pipes among the components of the heating surface have been installed. The water discharge, steam exhausting, air exhausting, sampling, and separator auxiliary systems, as well as sootblowing system all have been installed to the extend of allowing to carry out the test.
5.1.5.4 All the welded attachments to the pressure parts, such as the seal components in heating surface within the scope of hydraulic test to be welded with pressure parts, hood nails, rub-proof/vibration-proof covers or plates, thermal-engineering measure points, rigid beams, once sealing members shall all have been welded completely, and inspected and accepted.
5.1.5.5 Temporary steel members welded on the pressure parts shall have been cut off and grinded smoothly, without any damage to the base material.
5.1.5.6 Temporary stoppers like safety valves, main steam outlet pipes, and plates shall all of the required strength.
5.1.5.7 According to the drawings, all the expansion position of the boiler has been inspected in conformity to the boiler expansion requirements. The expansion indicators shall have been mounted and welded.
5.1.5.8 All the welding work of the pressure parts have been finished, and inspected in conformity to the requirements.
5.1.5.9 All the stairs, platforms, handrails, and temporary scaffolds to be used during the test should all be accessible, and equipped with enough lighting facilities. Both the inside and outside of the boiler should be cleaned without rubbish.
5.1.5.10 Temporary water supply system for the test shall have been built and tested.
5.1.5.11 Free communication network exclusively for the test will be maintained on the test site and special radio channel will be set up for the test.
5.2 Hydraulic test procedures
5.2.1 Fill water into boiler water system and superheating system.
5.2.1.1 Open water discharge valve in the lower header of the water cooling wall.
5.2.1.2 Open air exhausting valve of the overall system, and close all the other valves.
5.2.1.3 Start the water feeding pump and open the outlet valve to fill water into boiler.
5.2.1.4 Whenever water overflows out of any the air exhausting valves in each system, turn on and then turn off the air exhausting valve for 3-5 times to ensure no air stays in the system. Then close the exhausting valve, and stop filling water.
5.2.2 Pressure test
5.2.2.1 Fully fill the temporary water tank for the pressure test, open the outlet valve and outlet re-circulating pipeline valve of the pressure test pump, and then open the discharge valve in the lower header of water cooling wall to start boosting the system pressure.
5.2.2.2 Use the re-circulating valve in the pressure boosting pump to control the rate of pressure rise within 0.294MPa per minute. Persons will be assigned to watch the pressure gauges in the pressure boosting pump outlet, and in the boiler top’s superheater outlet header for the pressure change, and meanwhile they will keep contact with the general director timely.
5.2.2.3 When pressure rise to 10% of the required test pressure 0.75 Mpa, close the outlet valve and bypass valve in the pressure boosting pump. Carry out overall inspection of the pressure test system for any pressure decreasing, leakage, crack, deformation or damage. It’s up to the general director and site engineer to decide whether to go on boosting the pressure, based on the inspection result.
5.2.2.4 When the pressure rise to the normal operation pressure 6.0Mpa, stop the pressure boosting pump and carry out overall inspection of the system for any pressure decreasing, system leakage, crack, deformation or damage. The inspection result and pressure variation condition will be recorded.
5.2.2.5 Adjust pressure rise at a fairy low rate. When the pressure rise to the required testing pressure 7.5Mpa, close the outlet valve and the bypass valve of the pressure boosting pump and shut down the pump for 5 minutes. During this break, observe the readings change on the pressure gauge, after the BTL Engineer’s approval, start to reduce the pressure. Slightly open the outlet valve and bypass valve in the pressure boosting pump to reduce the system pressure to the normal operation pressure (keep the pressure reduce rate at 0.3MPa per minute), and stop to inspect the overall system for any leakage. All the defects that found during the inspection shall be recorded in the Record Form.
5.2.2.6 Slightly open the re-circulating valve of the pressure test pump and gradually reduce the system’s pressure. When the indicated reading on the pressure gauge of the superheater outlet header comes to zero, fully open the water discharge valve and the air exhausting valve on the boiler top to discharge water. Till now, the hydraulic test of boiled ends.
6 Hydraulic Test Staff Organization
General Director: 1
Technical principal (site engineer): 1
Pump operators: 2
Electricians: 2
Boiler top instrument readings recorder: 1 (to observe water pressure and do relevant
recording work)
Valve operators: 2
Front hearth inspectors: 10
Rear hearth inspectors: 6
7 Temporary Water Supply System
Connect one Φ159 pipe from the water source to the temporary water tank. A water pump will be connected to the inlet valve of boiler water feeding operation table. See following sketch:
8 Safety
8.1 Generally, conform to the SSMP safety regulations.
8.2 Special requirement for the hydraulic test:
8.2.1 Before the test, carry out once overall inspection about the equipment and valves in the hydraulic system. When boosting the pressure, a warning sign will be set up on the test area to warn other workers not to enter this area. During test, person who not participates in this test is forbidden to enter this area. While boosting the system pressure, nobody is allowed to work in the boiler body area, and only when all the persons have left the boiler body can the boosting start.
8.2.2 All the work that has nothing to do with the hydraulic test should stop while testing. Welding or hitting the pressure pipes or equipment is forbidden. While boosting the pressure, the heating surface expansion condition should be observed, and any abnormal condition should be settled before go on boosting.
8.2.3 Pressure boosting pump, water feeding pump and all the valves should be observed maintained by designated person. The performance of the boosting pump should be tested and confirmed as reliable before the hydraulic test. Firm scaffold, level access and enough lighting should be built for each valve operation point and weld inspection point.
8.2.4 While boosting pressure, the connection between pressure boosting pump and the boiler top in-situ pressure gauge should be reliable, prevent the pressure is over-boosted.
8.2.5 The workers to observe pressure gauge, pressure boosting pump and valves operators should have a clear idea of the exit route. In case of over-boosting, patrol inspection is not allowed. While inspection, nobody is allowed to stand against the temporary stop plate, weld, water level meter joint, as well as the flanges joint. Person who takes part in this test can not work by himself alone, while inspecting, he should in the supervision of someone else. After each inspection work, the inspection team principal should check his team members and the tools.
8.2.6 All the people participate in the hydraulic test should follow the direction, and have a clear distribution of his job and the take the relevant responsibility.
8.2.7 Anyone finds any abnormal situation during test, should report to the general director immediately, treating the problem by himself is not allowed. Inspectors should
8.2.8 Special medical staff and vehicle will be allocated for potential rescue during the hydraulic test.
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