Methanol synthesis reactor maintenance overhaul

1、General
1.1 Scope of application
  This procedure applies to the overhaul and maintenance of methanol synthesis Reactor R2001.
1.2 Equipment overview
Methanol synthesis reactor R2001 belongs to fixed-bed gas-solid-phase tube catalytic reactor, which is similar to a vertical shell-and-tube fixed tube-sheet tube heat exchanger with steam by-product, and the tube sheet is directly welded to the shell of the tube box, which cannot be connected by lan. The upper and lower heads are hemispherical heads, with a gas distributor set up at the syngas inlet of the upper head, the heat exchanger tubes and the upper part of the upper tube plate are filled with copper-based catalysts, and the refractory balls are filled with refractory balls after laying the wire mesh on the upper part of the catalysts; the refractory balls are filled with refractory balls underneath the lower tube plate, and the refractory balls and the reaction gas outlet of the head are equipped with a made part between the reaction gas outlets of the head. The upper part of the shell side cylinder of the synthetic reactor is connected with steam outlet pipe and boiling water outlet pipe, and the lower part is connected with water inlet pipe.
2、Equipment integrity standards
2.1 Parts
a) The parts are complete and the quality meets the requirements.
b) Shell, heat exchanger tube without obvious scouring, corrosion defects.
c) The deviation of verticality of equipment cylinder is 0.5/1000.
d) The foundation is intact, and the ground bolts are tight and complete.
e) The valves on the pipeline are flexible and effective; the pipeline and pipe fittings are reasonably installed, firm and complete, and clearly marked.
f) Thermocouples are sensitive, accurate and reliable.
g) Anti-corrosion and anti-freezing facilities are complete and effective.
2.2 Equipment performance
a) Each part of the temperature, pressure, flow and other parameters in line with the operating procedures.
b) There is no abnormal sound and vibration in the operation of the equipment body and pipeline.
2.3 Technical information
2.3.1 Technical information is accurate and complete, including at least:
Equipment files, as-built drawings, manufacturing, installation of technical documents (including non-destructive testing records, equipment manufacturing certificate, pressure vessel manufacturing quality certificate, installation project handover technical documents), equipment debugging records, instruction manuals
i) equipment structure and wearing parts drawings
j) equipment operation cumulative time
k) equipment maintenance program, the actual repair records and technical appraisal records
l) equipment technical transformation programs, drawings, material quality certificates, construction quality inspection of technical documents and information
m) safety accessories calibration, repair and replacement records
n) equipment defects in previous years, accident records and processing reports
2.3.2 Complete operating procedures and maintenance and repair procedures.
2.4 Equipment and environment
a) No running, bubbling, dripping or leaking.
b) The surface of equipment and foundation is clean and free of debris.
c) The environment around the equipment is clean, no water and no debris.
3、Routine Maintenance and Common Troubleshooting
3.1 Daily maintenance
3.1.1 Control the process indicators according to the operating procedures.
3.1.2 Regularly check the operation of the equipment according to the inspection route and make operation records.
3.1.3 Clean the equipment frequently to keep the equipment clean, free of dirt and debris.
3.1.4 Discover the process material inlet and outlet pipelines, loose bolts, pipeline vibration and timely treatment.
3.1.5 Eliminate equipment defects in a timely manner; make records of defects that cannot be dealt with temporarily without affecting safe production, and deal with them when stopping for maintenance.
3.1.6 Repair the parts with poor anti-corrosion, incomplete insulation or cracked and peeled insulation in time.
4. Overhaul content
4.1 Medium maintenance
4.1.1 External macro-inspection of the container, mainly including:
a) The insulation layer is damaged, peeling off, wet;
b) Abnormal vibration, rattling, mutual friction between the vessel and adjacent pipelines or components;
c) support damage, foundation sinking, tilting, cracking, fastening bolts intact;
d) Discharge (exhaust, sewage) device.
4.1.2 Open the manhole, check the inner wall of the upper pipe box, the surface of the pipe plate for macro-inspection and check the condition of the internal parts
4.1.3 Repair and replace some valves
4.1.4 Replacement of touch coal and inspection of inlet and outlet pipes
4.1.5 Thermocouple inspection or calibration, replacement
4.1.6 Handle equipment defects that cannot be handled on a daily basis
4.2 Overhaul
4.2.1 Intermediate repair all content
4.2.2 Remove the insulation layer, check the rust and corrosion of the outer wall of the equipment, macroscopically check the external weld for cracks, and after checking, remove the rust, anticorrosion, and insulation
4.2.3 Comprehensive inspection and examination according to HG25001 "Pressure Vessel Maintenance and Overhauling Regulations".
4.2.4 Hydraulic test
5、Methods and quality standards for overhaul
5.1 General requirements
5.1.1 Open the upper and lower manholes and dismantle the lower elbow.
5.1.2 Open the catalyst unloading hole and unload the refractory ball and catalyst respectively.
5.1.3 Check the shell, tube plate and column according to HG25001 "Pressure Vessel Maintenance and Overhauling Regulations".
5.1.4 There shall be no bubbles, delamination and cracks in the anticorrosive layer of the equipment after repair, and the damage found shall be repaired.
5.1.5 Fasten the studs should be symmetrical and uniform, and the stud nuts should be coated with molybdenum disulfide.
5.1.6 When repairing corrosion, cracks and other defects of the cladding layer, the defects shall be removed and qualified by penetration test before cladding, and ER309L shall be used for the transition layer, ER308L shall be used for the surface layer, which shall be preheated before cladding, and the surface layer shall be penetration and ultrasonic test after stress relief heat treatment after cladding.
5.2 Refractory ball filling
5.2.1 Enter the reactor from the manhole of lower head, lay the wire mesh on the support, firstly fill the refractory ball from the manhole of lower head through the manhole of support according to the drawing of equipment, the refractory ball should be distributed evenly on the support as far as possible, and finally make the ball and the edge of the manhole of support flush.
5.2.2 Seal the manhole of the support piece, change to the upper head to enter into the reactor, fill the refractory balls from the column tube, measure with a well-marked lead hammer so that the depth of each point is the value stipulated by the process, and the refractory ball filling is completed.
5.3 Catalyst filling
  Carry out according to "Methanol synthesizer catalyst loading program".
6、Commissioning and acceptance
6.1 Preparation before test run
6.1.1 After the equipment is repaired in large or medium scale, on the basis of the self-inspection of the repairing unit, the competent department of the equipment will preside over the acceptance group including the repairing unit and the using unit together with the departments of production and safety, and review the overhauling, construction, overhauling records, handling of special conditions and remaining problems, etc., and confirm that all the overhauling items are completed and the quality of the overhauling is recognized.
6.1.2 The production process department develops a test program.
6.1.3 Purging according to the test program.
6.1.4 Remove inlet, outlet and related blinds.
6.1.5 Pass gas replacement according to process requirements.
6.1.6 Inspection and repair of the site work finished material clean site clear.
6.2 Test drive
6.2.1 Operators must be in accordance with the commissioning program for commissioning, while maintenance personnel should be on site to cooperate with the inspection.
6.2.2 Check and debug the thermocouple, require sensitive and accurate.
6.3 Acceptance
6.3.1 The equipment into normal production, the technical indicators to meet the requirements of the process can be recognized that the final quality of the maintenance qualified.
6.3.2 After passing the test run, that is, for acceptance procedures.
7, maintenance and overhaul safety precautions
7.1 Maintenance and overhaul safety regulations
7.1.1 Inspectors must be familiar with the equipment process parameters, processes and equipment performance and characteristics, and strictly control the process indicators.
7.1.2 Keep the inspection route clear and well lit at all times.
7.1.3 Firefighting and protective equipment are in standby condition.
7.1.4 Comprehensive safety and reliability inspection of surrounding facilities and temporary facilities must be carried out before inspection and repair; confirm that the equipment is not under pressure before loosening the studs; the reactor must be replaced and qualified before entering.
7.2.5 Lifting equipment and tools must be safety checked, and lifting equipment must be operated by specialized personnel.
7.2.6 Temporary use of electricity to implement the "fertilizer production safety and technical regulations" provisions.
7.3 Test run safety regulations
7.3.1 Trial must be a person in charge of the command, maintenance, operation personnel found problems should be promptly reported to the person in charge of the trial, deal with.
7.3.2 Strictly according to the trial program and operating procedures.
Source: Reprint
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