2017 Work Summary: Electrical and Instrumentation (Statistics completed)

Thread Content

Summary of Electrical and Instrumentation Work in 2017 Company Leadership: Throughout the year 2017, with the care and support of the company’s leadership, as well as the suggestions and assistance from the Production Department, the following tasks were primarily completed. The report is as follows: 1. Technical renovation of the low-pressure steam flow meter FT901 (cost: 75,000 yuan). The sensor used in the original low-pressure steam flow meter for trade settlement was a V-cone flow meter, and multiple such meters in the system have been operating improperly. Practice has shown that this type of instrument has unclear requirements regarding its installation method and pressure sampling approach, as well as uncertain measurement accuracy of the sensors. When these types of flowmeters, used for measuring low-pressure steam, were put into use in September 2005, the following problem arose: even though there was actual steam flow, the measurement results showed either no flow at all, or a flow rate that did not change as the load changed ； When there is no steam flow during parking, the measured value shows full flow. And almost every time it stops, it needs maintenance. Although two adjustments were made successively (changing the direction of the flow meter sensor and digging a pit to lower the pressure sampling point), abnormalities as severe as before are now rarely observed in the measurement of low-pressure steam flow; nonetheless, the steam production rate calculated based on these measurements is still considered to be on the low side. Additionally, in accordance with the **specifications**, the temperature and pressure compensation measurement points should be installed behind the flow sensor. But after adjustment according to **standard specifications, the measured value becomes even lower. The measurement system has not been calibrated by a third-party (authorized) institution. This technical upgrade involves adding a flow meter of the best type currently available for steam measurement – an vortex flow meter – behind the existing flow meter. It is equipped with temperature and pressure compensation as well as on-site accumulation functions, allowing for the direct display of the mass flow rate of steam. The original measurement method will not be removed for now to facilitate comparison ； It also facilitates things by providing a backup measurement system for reference in case one set of measurement systems fails. The manufacturer has also chosen a top-tier brand in this field – the products of Shanghai Yokogawa Vortex Flowmeter (a Sino-foreign joint venture). These products have been proven to be of stable and reliable quality, with high measurement accuracy, through their long-term use in our company’s systems; over the past 5 years, this measurement system has required almost no maintenance. The total investment in the equipment is 73,000 yuan, which is 8,000 yuan less than that of the original phase one. Construction cost: 0.2 million yuan. The temperature and pressure compensation measurement points comply with **standard specifications ； Use pulse (digital) measurement directly to minimize system measurement errors ； The key instruments have passed the calibration by **legal metrology authorities as well as the calibration and certification by Wengfu Metrology Station. The renovation was successfully put into operation on the first attempt, and long-term statistical data show that the new gauge is 1.25 times larger than the original one. Based on this calculation, the measured loss from the previous table is approximately 1.7 million yuan per year. Due to the significant differences in the measurement data between the old and new meters, Party A’s metrology station found it difficult to accept them at first; however, through the mediation of the company’s management, they finally acknowledged the accuracy of the new meters. The new table has been involved in the monthly trade settlement. Attached is a comparison table of the measurement data from the old and new flowmeters before and after the technical modification:
Item, 11:00 on October 12, 15:30 on October 19, Cumulative difference (tons), Cumulative time (hours), Instantaneous value (tons/hour).
Data from vortex flowmeter F901B: 9920, 14331, 4411, 172.5, 25.57.
Data from V-cone flowmeter F901: 298928, 302453, 3525, 172.5, 20.43.
Percentage underestimation relative to vortex flowmeter: 0.20. Percentage underestimation relative to V-cone flowmeter: 0.25. Correction factor (to increase values): 1.25.
2. Modification of the DN1200 bypass control butterfly valve for the second heat exchanger (cost: approximately 020,000 yuan). The bypass control butterfly valve for the second heat exchanger has been malfunctioning for a long time. The valve failed even before it was put into operation in Phase II in September 2005, showing sticking, and it remained immobile despite multiple attempts to fix the issue ； In April 2007, new valves were installed and adjustments were made, but it still didn’t work. The main issue is that the valve cannot be opened or closed, which makes it difficult to raise the temperature during startup ； The switching regulation failed, resulting in poor adjustment of the production load ； The long-term operation of the catalyst at elevated temperatures, particularly its impact on the lifespan of new catalysts, also limits the possibility of improving conversion rates by raising the temperature in the later stages of catalyst use. Over-temperature operation data show that when the valves failed, the inlet temperatures at the second stage of the converter remained at 464°C and 477°C respectively over an extended period of time℃ ； After the modification, the inlet temperature can operate normally within the range of 430°C and 435°C as specified in the operating procedures. This indicates that the inlet temperature of the original two-stage catalyst exceeded the limit by 34~47°C. In this renovation, the valve shafts were replaced, the valve plates were modified, and the valve shaft positioning system was adjusted (a system that was developed in 2005; it is a mature technology proven through long-term use, including three patented technologies that have been filed). The materials used for the renovation were basically the existing waste materials from the company, and no valves were replaced or removed. This renovation was successfully put into operation. It saves on the costs associated with \"regular\" equipment updates (each update costs at least 120,000 yuan, not including the costs related to disassembling and reinstalling the equipment). More importantly, it facilitates the production process and prevents indirect losses resulting from the catalyst operating at elevated temperatures for extended periods. 3. Modification of the air volume meter for the turbine fan (cost: 0.85 million yuan). The original air volume sensor in the second system was a V-cone flow meter, installed in the inlet duct of the fan with an inner diameter of φ1700 mm. The outer diameter of the cone of this flow meter was 1288 mm, resulting in a clearance of only 206 mm between the cone and the inlet duct of the fan. This meant that the minimum cross-sectional area of the fan’s inlet passage was only 43% of that of the inlet duct itself, leading to an increased inlet resistance. The negative pressure at the fan inlet reached 0.76 KPa, which is more than twice the negative pressure of 0.36 KPa at the fan inlet in the first system. The system uses Ba-type flow meters, which are long rods with an outer diameter of less than φ30 mm that pass through the fan inlet pipe; their structure ensures that the irrecoverable pressure loss caused by the flow meters is much smaller. The increase in negative pressure at the fan inlet reduces the fan’s surge margin, leading to frequent surging and compromising the fan’s long-term safe operation ； Fan operation also consumes a lot of energy. For this technical upgrade, domestic Anubaa flow meters were selected, with an investment of 0.58 million yuan, which is much less than the 70,000 yuan required for the original flow meters. After the modification, the measurements became stable and reliable; the negative pressure at the fan inlet dropped from 0.76 KPa before the technical upgrade to 0.32 KPa, achieving the desired goal of energy savings and reduced consumption. Converted to power consumption, the calculation is as follows: Q = *t = *8000 ≈ 80496 (kWh). In the formula above, SCMM represents the flow rate of gas under standard conditions, with the unit being m3/min ； Δp is the irrecoverable pressure loss, in Pa ； K is the absolute temperature of the gas, and P is the absolute pressure of the gas, in units of Pa ； t is time, in hours. After the technical upgrades, annual energy consumption is reduced by 84,521 kwh, which is equivalent to approximately 40,250 yuan. 4. Modification of the heating power supply system for the preheating furnaces in the two systems (cost: 0.3 million yuan). The existing on-site power distribution equipment for the heating systems of the company’s first and second systems has very poor corrosion resistance, and it is severely worn out due to corrosion. It starts via autotransformer step-down starting; the circuit is relatively complex with many contacts, and failures occur frequently during use, affecting operation almost every time it is started. Through careful analysis and theoretical calculations, and by using the used stainless steel distribution cabinets taken from the sulfur melting section along with existing components, the heating systems of the preheating furnaces in systems 1 and 2 were upgraded. After the modification, direct starting was adopted, which simplified the circuit, reduced the number of contacts, and **lowered the failure rate. After several tests while driving, the modification was highly successful. Every time it is used for driving, everything goes smoothly; it not only features simple operation and reliable performance, but also solves the corrosion problem of the on-site distribution cabinets. 5. Automatic control renovation of the condensate water recovery pump (cost: approximately 0.1 million yuan). Previously, the operation of the condensate water recovery pump was controlled based on the water level indicated by a radar level gauge, with operators needing to be present on site to operate it, which was quite inconvenient. In this renovation, a float and two limit switches are used; the float moves as the water level changes, thereby activating the limit switches and enabling automatic control of the pump’s start and stop. This approach is both simple and reliable, while also reducing the workload for the operators. 6. Electrical automation upgrade for the melt sulfur condensate recovery pump (cost: approximately 1,000 yuan). The original control system for this pump relied on a magnetic flap level gauge in combination with variable frequency control, which resulted in high failure rates and high maintenance costs. This renovation uses two sets of reed switches and two intermediate relays to achieve automatic control, thereby **reducing** the failure rate and maintenance costs.