Innovative preset for imported circulating hydrogen compression facilities
See K-3201 main design parameters. K-3201 Main design parameter medium H 2 (small amount of CH + H 2 S) medium molecular weight 5. 49 ~ 7. 72 motor power / kW 1566 inlet flow (standard state) / m 3? h - 1 46000 inlet pressure / MPa 1. 1 inlet temperature / °C40 outlet pressure / MPa 1. 80 section outlet exhaust temperature / °C98 section outlet flow (standard state) / m 3? h - 1 23000 second stage outlet exhaust pressure / MPa 1. 65 second stage outlet exhaust temperature / °C108 second stage outlet flow (standard state) / m 3? The original design process of the h-1 2 23000 reforming unit is that the circulating hydrogen gas enters the K-3201 inlet directly from the tank top after the gas-liquid separation in the reforming gas-liquid separation tank (hereinafter referred to as D-3201). The K-3201 is an intermediate suction centrifugal compressor. A part of the hydrogen is extracted from the middle stage 6 impeller, and the rest is extruded from the 7th stage impeller. After the compressed hydrogen is compressed, the hydrogen gas discharged from the impeller outlet of the seventh stage is a hydrogen which is directly mixed with the gasoline to the hydrogen mixing point, and is heated and heated to enter the first and second reforming reactors respectively. The hydrogen extracted from the sixth stage impeller in the middle of the compressor, that is, the second stage hydrogen is slightly lower in pressure, and then directly exchanged to the second stage mixed hydrogen point after heat exchange, and then enters the third and fourth reforming reactor reactions together. The final mixed reaction product is subjected to heat exchange and cooling, and then enters D-3201 for gas-liquid separation. Except for a small part of hydrogen in the top of the tank for pre-hydrogenation, most of the hydrogen is directly recycled to K-3201 for recycling. That is, the original design K-3201 has no buffer and liquid separation tank at the entrance and exit. The K-3201 itself has an anti-surge control protection system. When the unit runs out of surge, the anti-surge controller (U IC-1, 2) acts to open the control valve from its first and second outlets. The hydrogen, after cooling by the respective gas cooler, returns directly to the compressor inlet to increase the inlet flow to eliminate the hazard of surge to the unit. The K-3201 shaft seal design uses a T BS seal (Trapped Bushing Seal) and comb-tooth seal joint structure. The T BS seal relies on the high-speed rotation of the impeller fixed on the main shaft to drive the seal oil to generate oil pressure and seal in the seal chamber. The gas reaches the pressure balance to achieve a sealing effect. Considering that the reforming cycle hydrogen is clean and the content of corrosive medium is small and the system pressure is not high, the K-3201 uses a lubricating oil-sealing oil combined with a petrol station, that is, a tank is shared and the oil is pumped out by an oil pump. The oil distribution is then carried out via the respective regulating valves. The sealing oil enters the TBS seal and flows in three ways. The seal is returned to the oil tank directly by the seal on the atmospheric side, and the oil tank is controlled by the high tank hydraulic control valve after the other impeller is cooled, and the oil return in the seal on the process side is A small amount of process gas leaked through the comb seal is separated into an oil separator of the seal oil system for separation, and the separated seal oil is further separated from the degassing tank and then returned to the tank for repeated use. K-3201 is equipped with a buffered isolation gas in the middle of the comb seal. It is required to be filled with cleaning gas and process gas to avoid contamination of the seal oil by process gas. The original design is directly returned by a line exiting the second stage of the compressor, that is, the medium used as the buffering isolation gas is the outlet circulating hydrogen without any treatment. K-3201 original design process. 1 The original supporting facilities are insufficient to affect the production 1. 1K-3201 inlet without liquid separator for production impact From the operation situation from 1993 to 1995, since there is no liquid separation tank at the inlet of K-3201, when the operation of the reformer fluctuates, that is, the D-3201 liquid control failure or the fluctuation of the liquid level is large, the circulating hydrogen is easy to be The gasoline component of the D-3201 tank is carried into the compressor body. In addition, when the unit runs in a surge condition, the anti-surge control valve is suddenly opened, and a large amount of condensed oil is precipitated when the outlet circulating hydrogen is cooled by the cooler and returned to the inlet. Because the K-3201 inlet has no liquid separation tank, the circulating hydrogen belt liquid causes the gas composition to be too heavy, causing the main motor to overload and stop. At the same time, due to the large amount of liquid belt, the shaft vibration and shaft displacement of the compressor are increased, and the shaft seal wear and sealing effect is deteriorated. According to statistics, from 1993 to 1995, the abnormal shutdown of the reforming device occurred to cut off the feed. Seven times, it was caused by the shutdown of the K-3201 inlet circulating hydrogen. In particular, the liquid control failure of D-3201 due to reforming gas-liquid separation tanks on May 15, June 18, June 18, and September 21, 1995, and December 6, 1995; May 25, 1995, K- 3201 Surge, making the circulating hydrogen severely bring liquid, causing the K-3201 motor to stop overloading or the shaft vibration large interlocking shutdown, which not only causes the device to cut off the feed, but also causes the individual bearing bush and seal of the unit to be worn accordingly. After the process, the tube was vented from the bottom of the K-3201 body during the process, and a large amount of gasoline was released from the first and second sections of the outlet anti-flying line cooler. 1. The impact of 2K-3201 outlet without liquid separator on production The original design of the K-3201 unit seal oil control system has certain defects, that is, when the system operating conditions (mainly pressure) change, the regulator control lag (sometimes controlling the valve card) makes the seal oil pressure less than automatic tracking adjustment. The internal oil return of the sealed oil circuit suddenly increases, and the sealing oil enters the cylinder from the seal due to the out-of-line discharge. In addition, the unit shaft seal TBS seal will increase the seal gap due to long-term running wear, and will also cause part of the seal oil to be trapped into the cylinder by the seal. The above two factors cause a large amount of lubricating oil to be carried into the reforming reaction system by circulating hydrogen. Since the lubricating oil component is relatively heavy and contains some metal additives, entering the reforming reactor will not only lead to the delicate reforming catalyst CB- 6. The decrease in the poisoning activity of CB-7 also promotes the carbonation of the surface area of ​​the catalyst bed in the reactor, which also affects the activity of the catalyst and reduces the depth of the reforming reaction. The direct performance is that the temperature drop of the reaction is reduced, the octane number of the reformed gasoline cannot be increased, the hydrogen production is correspondingly reduced, and the normal production of the subsequent diesel hydrogenation unit is affected. From 1993 to 1997, due to the above reasons, the sealing oil was injected into the system from the compressor cylinders five times, and each time it had a large negative impact on the reforming reaction, resulting in a significant decrease in the temperature drop of the reforming reaction. Especially at the end of the fourth production cycle of the equipment in March 1997, due to the large variation of the system operating conditions, the K-3201 sealing oil control valve was stuck and could not be adjusted, resulting in a large amount of sealing oil from the compressor cylinder into the reforming system. Not only damages the reforming catalyst, but also completely destroys the molecular sieve in the molecular sieve tank in the front of the reactor, which forms an extremely passive production situation and also causes great economic losses. 1. 3 buffer isolation gas without cooling, the impact of filtration facilities on the unit seal In actual production, due to factors such as corrosion of equipment and pipelines, D-3201 gas-liquid separation effect, etc., the circulating hydrogen gas contains a small amount of mechanical impurities and light gasoline that has not been completely separated. The original design of the buffer isolation gas is directly returned from the two-stage outlet hydrogen, which will pollute the sealing oil when it is mixed with the oil in the seal, because the oil return in the seal is recycled to the tank, which gradually pollutes the tank. lubricating oil. Since the buffer gas is used, the sealing oil of the unit has been polluted to varying degrees. As a result, the acid value of the lubricating oil in the fuel tank becomes larger, the flash point and viscosity become smaller, and the mechanical impurities become more and more serious, which seriously threatens the normal operation of the unit. Therefore, it is necessary to frequently add a large amount of new lubricating oil to replace the already deteriorated lubricating oil, resulting in great waste. At the same time, the circulating hydrogen gas used as the buffer isolation gas directly returned by the outlet is relatively high (110 °C), and the actual use proves that it is impossible to cool the sealing member at all, and it is easy to cause the sealing oil to generate high temperature coking, which seriously affects the normal operation of the sealing structure. , which reduces the sealing performance and brings unsafe factors to the operation of the unit. 2 complete facilities In view of the above situation, the measures existing in the unit were taken in different stages to improve the problems. 2. 1 Add an inlet buffer tank According to the actual production, the circulating hydrogen flow rate (standard state) is relatively large, about 46000M 3 / h. It is obvious that the reforming gas-liquid separation tank with a specification of 1800mm×8054mm cannot completely perform gas-liquid separation, plus production. Occasionally, abnormal conditions such as sudden surge of the unit, etc., the unit's stable operation is obviously not guaranteed. On this basis, it is proposed to add a buffer liquid separation tank at the inlet of the circulation machine to further remove the gasoline carried in the circulating hydrogen under normal or abnormal conditions. At the end of 1995, when the equipment was shut down for maintenance, a buffered liquid separation tank with a diameter of 1800 mm and a volume of 16.56 m 3 and a metal foaming net was installed at the compressor inlet, and the anti-surge line of the unit was changed back. Before the inlet of the dispensing tank. 2. Add a buffer tank to each of the first and second sections of the exit. At the beginning of 1997, under the premise of fully considering that the pressure drop of the reforming system did not exceed the standard, it was proposed to add a liquid separation tank in the first and second sections of the compressor to ensure that a small amount of lubricating oil was exported at the initial stage of the running oil loss. Effective gas-liquid separation in the tank, and then remove the lubricant. At the same time, timely measures are taken to carefully adjust the unit's sealing oil system to prevent a large amount of running oil from running out and to protect the reforming catalyst from lubricating oil. In May 1997, two liquid separation tanks with a diameter of 1400 mm and a volume of 2.8 m 3 were completed and put into operation during the inspection period. 2. 3 Add a cooler and a liquid separation tank to the isolation buffer gas return line. Through the analysis of the principle of the compressor seal structure, it is considered that only by lowering the temperature of the isolation buffer gas, removing the light gasoline and other mechanical impurities in the gas, the sealing environment can be more thoroughly improved. That is to say, a cooler is designed to cool the isolation gas, and at the same time, a liquid separation tank is used for separation and purification, so that the buffer isolation gas can reach a low temperature and a pure condition, so that the isolation cooling effect can be truly achieved. Therefore, a cooler and a gas-liquid separation tank were added to the buffered isolation gas line returned from the original two-stage outlet, and the operation was carried out at the time of the equipment maintenance in May 1997. 3 improved use effect 3. 1 completely eliminated the downtime caused by serious circulating hydrogen After the K-3201 inlet is used for the dispensing tank, some gasoline can be removed from the bottom of the tank, and the purity of the recycled hydrogen is greatly improved after another separation. In particular, on April 3, 1996, there was a situation in which the reformed gas-liquid separation tank was severely liquidated due to the failure of the liquid control. Because the inlet has a liquid separation tank, the large amount of gasoline was separated again to protect the normal operation of the unit, and the treatment liquid was contacted in time. The valve is controlled to prevent the device from cutting the feed failure. On March 7, 1997, due to operational fluctuations, the unit entered the surge operation. The K-3201 first and second anti-flying control valves were opened urgently, and a large amount of gasoline was removed from the inlet liquid separation tank after the surge was eliminated. It is precisely because the compressor is equipped with an inlet liquid separation tank, and the operator de-liquidizes in time. After the transformation and improvement of the unit, there has not been a motor overload accident caused by severe hydrogen in the circulating hydrogen. 3. 2 Avoid lubricant contamination reforming catalyst After the two outlet liquid separation tanks are used, the unit will remove a small amount of lubricating oil that enters the cylinder of the compressor and enter the circulating hydrogen at the time of the commissioning of the sealing oil system at the start of the installation, and the unit will occasionally be produced in the usual production. A small amount of lubricant leaked out was removed. Since the production of the device in May 1997 for more than two years, there has not been any accident that the lubricating oil is brought into the reforming reactor to contaminate the catalyst, which completely protects the activity of the reforming catalyst and ensures the depth of the reforming reaction. The whole unit has been maintaining normal production of high octane gasoline. 3. 3 extended seal life, saving oil Since the K-3201 buffered isolation gas cooling and separation facility was completed and put into use, the circulating hydrogen returned as the buffered isolation gas from the outlet of the second stage of the compressor was cooled and separated and purified, not only the temperature was lowered, but also the light gasoline and machinery in the gas. The impurities are separated. After the injection and sealing, the isolation cooling effect is very good. The lubricating oil has not deteriorated since the unit is running, and the shaft sealing performance is good, which ensures the stable operation of the unit and saves a lot of lubricating oil. 4 Conclusion K-3201 is the key equipment of the reforming unit. Due to the particularity of the reforming production process, the operation status of the K-3201 directly affects whether the equipment can be produced normally, and will also affect the production of the post-hydrogenation unit. Thanks to the above three perfect measures, the safe operation of the unit has been strongly guaranteed. Since the start of production in May 1997, it has been more than two years since the start of production, and the unit has not experienced any downtime and thus affects the normal production of the device. The realization of the "safe, stable, long, full, excellent" production of the device has fundamentally improved the economic benefits of the operating device, and truly achieved "less investment, more output." Universal Crusher for Medical Materials,Pigment Grinding Machine,Pvc Powder Grinding Machine Mixing Equipment Co., Ltd. , http://www.plastic-granulator-equipment.com