Search

In recent years, the safe and stable operation of natural gas pipeline has become the focus of the whole society. Long distance natural gas pipelines are mostly large-diameter and high pressure pipelines, so their safe operation is particularly critical. In the high-pressure natural gas pipeline transportation industry, the wall thickness of key points (elbows and tees) will be thinned due to long-term erosion of gas, resulting in serious consequences. Therefore, its wall thickness monitoring is a key work of long-distance natural gas pipeline operation units. At present, most of them adopt off-line monitoring, but the standardized monitoring cycle cannot be effectively determined, and there are no relevant standards in the industry. The author uses fluent simulation software to establish the model, and then modifies the model combined with the field data. Then, the model is used to analyze the influencing factors of key points (elbow and TEE) one by one, and select more important influencing factors to formulate the monitoring cycle of different points. The monitoring cycle can provide reference for the daily work of on-site operators, and then ensure the safe and stable operation of long-distance natural gas pipeline.

The complex coupling, coordination and complementarity of different energy in the integrated energy system puts forward higher requirements for the technology of multi-energy load forecasting. To this end, this paper proposes a novel multi-energy load forecasting model based on bi-directional gated recurrent unit (BiGRU) multi-task neural network. Firstly, through the correlation analysis, an effective multi-energy load input data set is constructed. Secondly, the input data set is utilized to train the BiGRU and master the evolution laws of multi-energy loads. Then, multi-task learning (MTL) is used to share the information learned by BiGRU from perspectives of different load forecasting tasks, so as to fully dig the coupling relations among various energy loads. Finally, different types of load forecasting results can be obtained. Simulation results show that BiGRU can simultaneously consider the known data of the past and the future, and it can learn more characteristic information effectively. At the same time, the proposed model utilizes MTL to carry out parallel learning and information sharing for forecasting tasks of various energy loads, which can dig the complex coupling relations among different types of loads more deeply, thus improving the forecasting accuracy of multi-energy loads.

The mixed oil treatment of Product oil is an important task of pipeline enterprises. The paperconcluded that the on-line back mixing technology was feasible, compared treatment methods from the perspective of safety and economic benefits. TheProduct oil pipeline is taken as the research object in this paper, studied the concentration distribution of mixed Product oil and amount of mixed Product oilunder operation and shutdown condition, and brief studied Product oil On-line back mixing technology. Combined with the demand and pipeline length, the mixing test is determined at CD station and CQ station. The operation process as follow: First, Product oilsamples areextracted from the pipeline. Second, the index parameters are detected after the oil samples are mixed with different proportions, and obtaining the blending potential under the theoretical situation, the result show that the mixing potential of gasoline is greater than that of diesel. Third, the field test do with arbitrarily mixed oil download scheme, which study two mixed oil surfaces. The required fund of dealing with the mixed oil is obtained combined with the download amount of mixed oil.Finally, comparing with the funds of the previous contaminated treatment methods, it is concluded that the On-line Back Mixing technology has great advantages in both safety and economic benefits.

Zhongwei station of West to east natural gas pipeline is connected to the north of Zhonggui line, and Guiyang station of China-Myanmar natural gas pipeline is connected to the south, which has important strategic significance in Southwest China. At present, the tie line mainly carries out gas transmission from Zhongwei to Guiyang. Only some pipeline sections and offload stations have reverse transmission function, while all compressor stations have no reverse transmission and pressurization function. In order to evaluate the flexibility of the operation of the Zhonggui line and give some suggestions for the preliminary reconstruction, this paper uses the SPS software to establish the pipeline model and simulate the specific working conditions, focusing on the two working conditions of the intermediate station injection forward transmission and the whole line reverse transmission. Through the simulation, we can get the following conclusions: 1. When the intermediate station injects forward gas transmission, which compressor station, gas transmission range and joint operation condition with China-Myanmar line need to be started for Zhonggui line; 2. When the whole tie line is reversed, it is necessary to change the location of the compressor station with the function of reverse transmission and pressurization. Through this study, we can give some reference and evaluation opinions on the lack of flexibility of the current tie line, and also give some reference opinions on the specific implementation of the improvement of the tie line operation flexibility in the future.

In the long-distance pipeline of product oil, gasoline and diesel oil are transported in batches. Due to the large difference of physical properties between the two kinds of oil products, there will be oil mixing at each interface. Because the index parameters of mixed oil do not meet the sales standard, it is necessary to track the interface accurately, so as to provide necessary reference for cutting mixed oil. The topography of southwest mountainous area is characterized by continuous large drop and U-shape, which brings difficulties to batch tracking of product oil pipeline. The previous method is not suitable for this type of pipeline. Therefore, it is necessary to re study the batch tracking method of this type of product pipeline, and use vs2019 to write batch tracking software for continuous large drop and U-shaped product pipeline based on this method. The batch tracking error of the software for this type of pipeline is within the acceptable range, which can provide more accurate reference for the operation control personnel

Division of labor can increase labor productivity. Compared with the division of agricultural production, the division of forestry production has a typical positive externality. It is more scientific to study the division of labor in forestry production. Under the “Three Powers Separated” structure, the behavioral capacity of farmers has an important influence on the division of forestry production. This paper uses the survey data of farmers in Fujian Province to analyze the farmer’s forestry production division of labor behavior from three perspectives of the behavioral ability, the transaction ability and the disposal ability. The results show that the variable of “the contracting right is more important than the management right” in the measure exclusive ability and the difficulty in obtaining transaction information on forestlands to measure the trading capacity, both positively affects farmers’ participation in the division of forestry production. Meanwhile, whether has changed the use of forestlands negatively influences the division of the forestry production. This not only enriches the research results of the forestry production division of labor theory, but also provides a new perspective for promoting the development of the forestry production division of farmers, and thus provides a new source for improving the efficiency of forestry management. It helps promote the connection between small farmers and the development of modern forestry.

The merits and demerits of the movable balance-weight schemes in the existing tower crane are summarized and analyzed. The new design of rotatable balance-arm, latticed crane head, platform and rotational upper support is put forward for top of crane SXD50. The rotatable balance-arm is composed of two parallel truss structures, platform, luffing mechanism and balance-weight. The balance-arm can be pulled to rotate around the rotational upper support by luffing mechanism under amplitude control system. The forward torque is equaled to the backward torque from the balance-arm to realize the moment equilibrium of crane body during working. The luffing mechanism of balance-arm on the platform can be as a part of balanceweight. The finite element model of balance-arm and crane head is built and the calculated results prove the rotatable balancearm system reliable and the structure strength satisfies the requirement of design.