Abstract: The oil pump is the main energy consumption equipment in the production and operation of the oil depot. Due to the mismatch between pump characteristics and pipeline characteristics, it is necessary to control the flow of the outlet valve of the oil pump according to the operating conditions to meet the needs of the production process. This flow adjustment method produces a large pump tube pressure difference before and after the outlet valve of the oil pump, and a large amount of energy is consumed before and after the pump outlet valve, resulting in the waste of energy. In the South a depot 6KV / 630KW KDY750-75 × 4-type transmission pump unit to promote the use of a set of high-pressure frequency control system produced by Leader Huafu company to achieve by changing the speed of the pump for different conditions adjustment, Elimination of pump tube pressure differential throttling loss, reducing oil consumption, saving energy and improve the process. First, the issue put forward Daqing Oilfield Nanyi Oil Depot mainly receives two main oilfield oil production plant - a production plant, two oil production plant, the total reserves of 50 × 104m3, equipped with 5 units of oil pump. The main technical parameters of the oil pump unit are shown in Table 1. Due to the mismatch between the characteristics of the oil pump and the oil pipeline (it is impossible to select the oil pump that matches the pipeline characteristics exactly during the process of pump selection), under different actual operating conditions, it is necessary to adjust the oil pump outlet valve Flow, according to the statistics 5 oil pump in a single pump, double pump, three pumps in parallel operation, three different operating conditions, the maximum opening of the oil pump valve outlet does not exceed 10% (more than 10% Motor exceeds the rated current and the motor is overloaded). Resulting in the pump valve outlet before and after the existence of a larger pump tube pressure difference, pump outlet valve throttling loss of a lot of energy, the pump made a lot of useless, shortening the maintenance period and service life of the pump unit, different Operating conditions under the pump outlet valve before and after the pump pressure differential statistics as shown in Table 2. Note: The data in the above table is based on the statistics of actual operating conditions of South Oil depot in 2002, the data in the table are average. As can be seen from Table 2, in the single-pump, double-pump parallel, three-pump parallel operation modes, the pump outlet valve has an average of 1.2Mpa, 0.7Mpa and 0.4Mpa throttling losses. In the pump outlet valve before and after the three conditions (single pump, double pump in parallel, three pumps in parallel) throttling loss due to the pump outlet valve resulting loss: N loss i = 0.278P loss iQi Where: N loss i: valve throttling loss power under different conditions, KW P loss i: valve throttling loss pressure in different conditions, Mpa Qi: displacement of single pump under different conditions, m3 / h N loss 1 = 0.278 × 1.2 × 750 = 250KW 250KW / 630KW = 39.7% N loss 2 = 0.278 × 0.7 × 700 = 136KW 36KW / 630KW × 100% = 21.6% N loss 3 = 0.278 × 0.4 × 640 = 71KW 71KW / 630KW × 100% = 11.3% It can be seen from the above calculation that under the three conditions of single pump, double pump in parallel and three pumps in parallel, the throttling loss of the outlet valve of the oil pump accounts for 39.7%, 21.6% and 11.3% of its rated power. Visible, energy waste is very alarming. Therefore, it is necessary to apply the variable frequency speed regulation technology on the pump unit to achieve the operating conditions based on the same bath, to meet the operating conditions through variable frequency operation, the pump outlet valve fully open, to avoid throttling loss of the pump outlet valve .
