The large centrifugal compressor is the core equipment of the production equipment, which plays a decisive role in both the production and the investment in the unit equipment. With the continuous expansion of the scale of the device, the volume of the single device is gradually increasing, so that the difficulty in manufacturing, transporting, installing and debugging the device is gradually increasing; the large centrifugal compressor technology is more complicated and the installation accuracy is higher. In the event of a fault or accident, the consequences are often very serious and the losses are quite heavy. Therefore, the protection system set for it is also quite complicated, and the single-machine test run is required after installation. Through trial operation, it can be achieved: check whether the configuration of each system of the equipment meets the design requirements; check and adjust whether the movement mechanism of each part of the unit meets the design requirements; verify and adjust the correctness and sensitivity of the electrical, automatic control system and its supporting facilities Inspection of the oil, gas (steam), water and other systems of the unit, the rigor of the process piping system and its equipment; inspection of the unit's vibration, shaft displacement, shaft temperature, pressure and other process parameters, and equipment design, manufacturing and Comprehensive quality assessment of installation quality, identify and eliminate hidden dangers, and ensure safe use of compressors.

Shaanxi Yanchang Petroleum Group Co., Ltd. Refining & Chemical Company (hereinafter referred to as refining and chemical company) invested a total of 4.8 billion yuan, completed 120 10 4 t / a reforming, 140 10 4 t / a diesel hydrogenation, 60 10 4 t / a Gas separation, 20 10 4 t/a polypropylene plant and its supporting projects, etc., there are three sets of large-scale centrifugal compressors, a brief summary of the problems and solutions in the test process, as a reference.

2 Introduction of three large centrifugal compressors

The three large centrifugal compressors are gas distributor propane compressor, reforming cycle hydrogen compressor and diesel hydrogenation cycle hydrogen compressor, and two back pressure steam turbines in three drive machines, produced by Hangzhou Steam Turbine Co., Ltd. One is a condensing structure, produced by Siemens Energy Industry AG. Two of the three main engines are produced by Shenyang Blower Group Co., Ltd., one of which is cylindrical and one is horizontally split; one is produced by Dresser-Rand, and has a cylindrical structure. The original planned reforming cycle hydrogen compressor also uses domestically produced machines. Only Shenyang Blower Group Co., Ltd. can produce in China, and it needs to be composed of two cylinders with a long shaft system. After many arguments, we used imported single-cylinder compressors.

The main technical parameters of the compressor unit are shown.

3 Problems, Causes and Countermeasures in the Process of Commissioning

In order to ensure the smooth progress of the test drive, the construction party and the general contractor each have a leader responsible, and the test contractor consists of four personnel from the general contractor, the installation unit, the manufacturing unit and the construction unit. The refining and chemical company has deployed the machine, electricity and instrument personnel with rich management, operation and maintenance experience in the company's scope. Before the test, the general contractor unit formulated the test plan according to the design documents, random data, relevant national standards and specifications. The test team members made a detailed and detailed discussion on the test plan and finalized the draft.

3. 1 propane compressor unit

First, the single-machine test of the steam turbine was carried out. During the warm-up of the test, it was found that the right side of the rear support of the steam turbine (standing at the output end of the steam turbine and facing the steam turbine) was too large (the design amount was 0 22 mm, actually The measurement has reached about 0 4 mm), and the others are within 0 05 mm. After that, the installation conditions of the steam turbine inlet and outlet pipelines are checked against the drawings. It is found that the outlet pipeline limit device is not installed, and the left side of the spring support is pulled. When forced to stop and cool down, when the standby group pipeline is lowered to normal temperature, the tie rod installation is carried out. After the installation is completed, the unit condition is checked and adjusted, and then the warming machine is started. When the outlet line temperature rises to about 120, the original tilted cat claw The offset was too large, the general contractor adjusted the tie rod, found that the force was not enough, was forced to stop again and cool down, and installed the top wire mechanism on the right side of the spring support, and then warmed up the warmer, when the temperature rose to 120 When adjusting the tie rod and the top wire, the amount of the cat claw that is tilted up can be controlled within the range, but the amount of the claw of the cat claw diagonal to the cat claw exceeds the standard, and the general contractor adjusts the other hanger. The lifting amount of the four cat claws of the steam turbine is within the required range. After the warm-up reaches the requirements, the test is carried out according to the test plan, and the test parameters of the steam turbine are good.

After the steam turbine is connected to the main engine, the unit is tested, the medium is air, the inlet and outlet are open to the atmosphere, and the unit is sealed with a random test.

In the process of warm pipe, the same problem as the single-machine test of the steam turbine was found. After the test unit of the general contractor, the multiple support hangers were adjusted several times to meet the test operation conditions and the test operation was carried out. The unit operated smoothly, but the claws were only partial. The amount of shift changes with temperature and exceeds the technical requirements. It is necessary to adjust the adjustment system and suspension system of the outlet pipeline in a timely manner.

Regarding this issue, we have had a special exchange with the general contractor. We believe that there is a problem with the design of the steam turbine outlet pipeline. The specification requires that the mating flange of the steam turbine pipe installation be parallel and concentric with the machine flange in the free state, the allowable deviation is parallelism 0 15 mm, radial displacement 0 5 mm; any pipe connected to the steam turbine during operation The joint force Fr and the combined moment M r satisfy the relationship of 0 914Fr+M r? 26 689De (equivalent diameter of connecting pipe) and other requirements. In this way, the vertical displacement of the cat's hot and cold cat claws is guaranteed to be 0 22 mm. The designer replied that there is no problem in the calculation of the pipeline stress, but the pipeline is not installed with the necessary constraints during the first installation, resulting in a stress center offset. However, according to the adjustment analysis of multiple cold and heat changes during the test run, and the detailed inspection of the installation site of the unit pipeline, we believe that this explanation is not convincing. First, the pipeline has undergone many changes and adjustments, and the cold state cannot be satisfied. In the hot state, the hot state cannot satisfy the cold state. Second, many of the supports on the pipeline are designed to be slip-type, but some of them cannot be effectively slipped. Third, the tie rods on the original design turbine outlet line cannot meet the pipeline stress requirements. The designer agreed to further accounting and recommended that the turbine outlet line be reinstalled at the appropriate time.

3. 2 reforming cycle hydrogen compressor

First, the single-machine test of the steam turbine is carried out. Under the command of the after-sales service personnel of Siemens, the steam turbine failed to reach the rated speed for many times, and all of them stopped due to the excessive vibration value, and each time started from about 3 000 r/m in, the vibration increased with the rotation speed. Gradually, but each time the vibration part is different, sometimes at the front end bearing, sometimes at the rear end bearing, and the vibration value increases faster than the test speed. The fourth test speed is less than 3 800 r/ m in, vibration The value has reached 70 m. It is measured by an off-line vibration tester with only one frequency. After-sales personnel of Siemens Energy Industry Co., Ltd. also tested the front and rear bearing bushes of the steam turbine, and the bearing bushes were in good condition. At the same time, detailed inspection and inspection of the steam turbine condensing system were carried out, which met the requirements of the design documents. We also hired experts from Sinopec outside units to agree that it may be that the rotor is unbalanced or there are loose animals on the rotor. The service personnel of Siemens Energy Industry Co., Ltd. contacted the relevant personnel of Siemens Energy Industry Co., Ltd. and transmitted the on-site situation and data collected to the headquarters of Siemens Energy Industry Co., Ltd., and the headquarters of Siemens Energy Industry Co., Ltd. suggested that the steam parameter test be carried out according to the factory test parameters. get on. Through the parameter reduction operation, the machine runs smoothly, and the mechanical performance and the self-protection of the turbine are smoothly carried out. The test data is good and meets the requirements of the equipment technical documents. Secondly, the main and auxiliary machines are synchronously tested. The medium is nitrogen, the speed is 4 800 r/m in, the pressure is 0 14 MPa, the seal is the official dry gas seal, the sealing gas is nitrogen, the whole unit is tested smoothly, the performance is good, and the parameters are consistent. Technical documentation requirements.

3. 3 diesel hydrogenation cycle hydrogen compressor

First, the steam turbine single-machine test was carried out, and the tests were successfully passed, and the performance was good.

Secondly, the steam turbine linkage compressor is tested. The medium is air, the compressor inlet and outlet are open to the atmosphere, and the seal is sealed with a random test. When the rotational speed is close to 7 000 r/m in , the shaft seal leakage at the output end of the steam turbine is large, and the higher the rotational speed, the larger the leakage amount. At the same time, a large amount of lubricating oil flows out from the sewage outlet of the compressor inlet and outlet, and is forced to stop the inspection. After inspection, the turbine shaft seal is intact and the clearance value is within the required range. The final analysis believes that: the compressor test seal can not meet the role of the seal lubricant, the protective gas flux is too large. During the test run, the turbine shaft seal leaks because the compressor seal gas and the isolated gas flux are too large, resulting in a large pressure in the bearing housing of the steam turbine output end, causing the lubricating oil to leak. After checking and adjusting the sealing gas, check the work before the unit is tested, meet the test conditions, and test again. When the speed rises to 1 500 r/m in, the check valve on the compressor outlet line sends a continuous knock. The sound, the higher the speed, the louder the sound, when the speed reaches 3 000 r / m in, due to the loud sound, forced to stop the inspection. Since the one-way valve is a valve imported from Spain and is a welded structure, the bonnet seal is its proprietary structural material through its structural analysis. There is no material on site, and the domestic agent is invited to the site, and there is no relevant sealing material, so it cannot The inspection was continually opened. Finally, through the analysis of the process and valves (shown in the process), we decided to remove the flange valve closest to the second check valve to check the check valve. After opening the flange, there is a considerable amount of oil flowing out. We think that the test seal of the unit is not well sealed, resulting in too many flow passages in the lubricating oil suction unit. The one-way valve emits a continuous knocking sound because the air flow carries a large amount of oil mist. The impact force of the check valve is increased, the adhesion force is increased, and the two check valve flaps are alternately opened and closed. Under the action of impact force, adhesion force, gas pressure and valve gravity, the impact on the valve seat is formed. , the sound of the sound. In order to eliminate the impact, we thoroughly cleaned the compressor flow path, and after the compressor sealing gas was adjusted, the test was carried out again, and the work went smoothly.

The above three units, after passing the test of the single machine test, are put into production and operation very well after the unit is put into production.

4 recommendations

a. The import and export pipelines of large-scale equipment, especially the steam turbine steam inlet and outlet pipelines are very important. Due to their export pipelines, the pipelines have large specifications, strong rigidity, high temperature and large expansion, which directly affect the long-term safe and stable operation of the turbine. Therefore, the stress of the piping, the release guide of the expansion amount, the mounting position of the spring support hanger, the selection of the spring support hanger, the setting of the pipeline slip bearing, the pipeline limit form, the selection of the limit point, etc. Etc., it should be repeatedly demonstrated and calculated to ensure that the joint force Fr and the combined moment M r of any nozzle connected to the steam turbine during operation meet the relationship of 0 914Fr + M r 26 689D e (equivalent diameter of the connecting pipe). Wait for the request.

b. The domestic compressor test seal should be improved to ensure that the lubricant can not enter the process airflow during the test run, causing pollution to the flow channel, or to develop a strict test plan, directly using the regular seal test, on the one hand, reducing the on-site workload; On the other hand, make sure that the lubricant does not get around.

c. The compressor and its supporting system must be installed with experienced professional installation units. In this way, many tasks before the test, equipment and electrician personnel can cooperate with each other. Otherwise, there are many problems left, which may cause the test work not to be scheduled. The program went smoothly.

d. The mechanical and instrument interface of the equipment body must be separated by material quality, and the interface form is easy to seal. This can reduce or eliminate run, run, drip, leak and other problems. Domestic machines must be run, run, drip, More effort is drained.

e. In vitro equipment wiring of domestic equipment is messy. More reference should be made to foreign equipment to improve the overall quality and appearance design level of domestic equipment.

f. The inherent reliability of the unit itself and the supporting system is the prerequisite for achieving high quality and smooth completion of commissioning and equipment safety, stability, long, full and excellent operation. Therefore, the selection, design and manufacture of equipment and its supporting systems are The key is the decisive factor, that is, the quality of the product is made, not tested. Therefore, the management of all aspects of the equipment in the early stage should be strictly controlled, and full-time supervisors should be invited when necessary.

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