Town gas daily load forecasting based on machine learning combinatorial algorithms:A case study in North China

Timely and accurate gas load forecasting is critical for optimal scheduling under tight winter gas supply conditions.Under the background of the implementation of“coal-to-gas”for winter heating in rural areas of North China and the sufficient field research,this paper proposes a correction algorithm for daily average temperature based on the cumulative effect of temperature and a set of combined forecasting models for gas load forecasting based on machine learning and introduces its application through a detailed case study.In order to solve the problems of forecasting performance degradation and complexity increase caused by too many influencing factors,a combined forecasting model back-propagation-improved complete ensemble empirical mode decomposition with adaptive-noise-gated recurrent unit based on residual sequence analysis is proposed.Back propagation(BP)neural network is used to analyze the main influencing factors,so that the secondary influencing factors are reflected in the residual sequence generated by the forecasting.After decomposition,reconstruction,and re-forecast,the mean absolute percentage error(MAPE)of the combined models for the daily gas load in the case study has been controlled under 1.9%,which is significantly improved compared with each single algorithm.The forecasting error before and after the temperature correction are also compared.It is found that the MAPE with the temperature correction is reduced by 1.7%,which reflects the effectiveness of the temperature correction to eliminate the impact of temperature cumulative effect and its contribution to the improvement of the forecasting accuracy for the combined forecasting models.

Dispel the Mist in the Reform of Oil and Gas Industry in China

The General Office of the CPC Central Committee issued the Opinions on Deepening the Reform of Oil and Gas System in 2017.Since then,the implementation works has been gradually rolled out.Among them,the operation mechanism reform of the oil and gas pipeline network is the most remarkable,attributing to the adjustment of organizational structure and operating model.Some discussions stress particularity of the oil and gas industry.

Cycle performance of Cu-based oxygen carrier based on a chemical-looping combustion process

The cycle life of oxygen carrier（OC） is crucial to the practical applications of chemical looping combustion（CLC）. Cycle performance of Cu/SiO2 prepared with a mechanical mixing method was evaluated based on a CLC process characterized with an added methane steam reforming step. The Cu/SiO2 exhibited high redox reactivity in the initial cycles, while the performance degraded with cycle number. Through characterization of the degraded Cu/SiO2, the performance degradation was mainly caused by the secondary particles＇ fragmentation and the fine particles＇ local agglomeration, which worsened the distribution and diffusion of the reactive gases in the packed bed. A regeneration method of the degraded OC based on re-granulation has been proposed, and its mechanism has been illustrated. With this method, the performance of the degraded OC through 420 redox cycles was recovered to a level close to the initial one.

International Cooperation on Energy under the “Belt and Road” Initiative

Since the implementation of the“Belt and Road”Initiative which China put forward more than five years ago,it has had a greater and greater impact and gained the recognition of more and more international organisations,as well as the participation of an increasing number of countries and regions.Although it was initially stigmatised as neocolonialism,it has proved to be contrary to historical colonialism by involving neither the occupation of resources by means of violence or threats nor the attachment of unreasonable constraints.The“Belt and Road”Initiative concerns open global cooperation,not small cooperation for the formation of cliques.Cooperation under the“Belt and Road”Initiative is benefiting an increasing number of people in the countries along the route.It has become a new driving force for promoting economic development and improving people's livelihood.It is constantly consolidating the fruitful achievements of globalization and marketization that mankind has already achieved.

Comparison and Performance Analysis of Heat Storage Equipment in Solar Heating System

Solar heating system is widely used recently. Heat storage equipment is the guarantee for steady performance of solar heating system. A design of latent heat storage exchanger with submerged coil was introduced with the structure, working principle, and the main advantages. This heat exchanger was integrated into solar heating system as the heat storage equipment. Advantage comparison of the designed heat exchanger in solar heating system with hot water tank was carried out. The analysis results show that the latent heat storage exchanger is superior to hot water tank obviously. The heat exchanger performance parameters and variations of these parameters are got： （1） with the increase of phase change material （PCM） volume ratio, heat storage equipment volume ratio decreases; （2） heat storage efficiency has the same varying tendency with outdoor and air temperature; while the bigger PCM volume ratio is, the weaker the effect of outdoor air temperature on heat storage efficiency is; （3） heat storage capacity and heat storage efficiency increase together; when PCM volume ratio is big, heat storage efficiency is high and the system can begin operating effcienfly and quickly; （4） with the increase of heat storage capacity, life cyde operation cost （LCOC） of system increases gradually in high speed; but with the increase of PCM volume ratio, the difference between the two systems LCOCs becomes smaller and smaller; （5） the reasonable range of PCM volume ratio is 0.5 - 0.7. Temperature characteristic analysis shows that, with the filled PCM, heat storage medium temperature presents several segments at different time, under conditions of different heat storage capacity and different PCM state.

Application of a Support Vector Machine Algorithm to the Safety Precaution Technique of Medium-low Pressure Gas Regulators

In the gas pipeline system, safe operation of a gas regulator determines the stability of the fuel gas supply, and the medium-low pressure gas regulator of the safety precaution system is not perfect at the present stage in the Bei- jing Gas Cxroup; therefore, safety precaution technique optimization has important social and economic signific- ance, In this paper, according to the running status of the medium-low pressure gas regulator in the SCADA sys- tem, a new method for gas regulator safety precaution based on the support vector machine （SVM） is presented. This method takes the gas regulator outlet pressure data as input variables of the SVM model, the fault categories and degree as output variables, which will effectively enhance the precaution accuracy as well as save significant manpower and material resources.

Research on Online Safety Precaution Technology of a High-medium Pressure Gas Regulator

In view of some of the characteristics of a high-medium pressure gas regulator, such as small fault samples, many fault types and complex fault features etc, in order to improve the accuracy of fault precaution in this paper, a fault diagnosis method based on the combination of the improved wavelet packet and pressure harmonic distortion rate is proposed. On the basis of the harmonic distortion rate of the outlet pressure and the energy value of each frequency band obtained by improved wavelet packet decomposition, the rules for fault data were summarized. Finally, a safety precaution model of the high-medium pressure gas regulator is established.