Experimental study on a new FCC spent catalyst distributor

In the regenerator of an industrial fluid catalytic cracker (FCC), uniform distribution of its solids reactant, i.e. spent catalyst, plays a crucial role in obtaining better regenerator performance. In traditional FCC unit designs, there was usually no spent catalyst distributor or some intuitive designs with simple structures, i.e. boat or pipe distributors in most China’s FCC units (1). In this study, we built a large cold experimental installation to evaluate the performances of various spent catalyst distributors. Distribution uniformity and solids flow resistance were the main target indices for distributor performance evaluation. The experimental results indicate that the boat distributor has the poorest performance, as solids flows preferentially through the few front openings. At high gas flowrates, the pipe distributor can obtain a relative uniform solids distribution, but its flow resistance is also higher. Good flowability of solids that is difficult to maintain throughout the distributor was found to be the root cause of their bad distribution performance. Referring to the idea of an air-slide solids transportation system (2-4), a new slot spent catalyst distributor was proposed. Its performance was systematically evaluated in a large cold model unit. It was found that the new slot distributor has a critical superficial gas velocity, beyond which good solids distribution uniformity and high solids transportation capacity can be both maintained. Compared with traditional boat and pipe spent catalyst distributors, the new slot distributor is much more advantageous comprehensively, e.g. in solids distribution uniformity, solids transportation capacity and operating flexibility. Please click Additional Files below to see the full abstract

Transportation of Raw Materials, Recondite Question in Manufacturing Enterprise

Based on the optimization theory, this paper studies the mathematical modeling problem related to the ordering and transportation of raw materials. The paper starts with reasonable assumptions, based on which the following factors are used as index: “average supply”, “order completion rate”, “average order value” and “standard deviation of supply” of each supplier, and the weight of each index is determined by using entropy weight method. On the premise of reasonable weight, the distance method of good-bad solutions (TOPSIS) is used to evaluate and rank each supplier, and finally, the most important supplier is selected. Then, a 0-1 programming model is established, in which “minimum order price” and “minimum loss” are taken as the objective functions, and the two-week inventory of the enterprise is combined with factors such as the loss rate of the forwarder, using MATLAB programming TOPSIS algorithm to solve the model to obtain the optimal ordering and transshipment plan. Considering the possibility that the enterprise needs low utilization of raw materials A and C, a bi-objective programming model is established to determine the weekly ordering and transshipment plan within the target weeks. On the other hand, when the number of suppliers is sufficient, the capacity of the forwarders limits the expansion of the capacity of the enterprise. Therefore, combined with the existing data, a linear programming model with the maximum production capacity as the objective function is established to obtain the maximum production capacity and formulate ordering and transshipment schemes. Finally, the solution process and results are summarized and analyzed

Online Modelling and Calculation for Operating Temperature of Silicon-Based PV Modules Based on BP-ANN

The operating temperature of silicon-based solar modules has a significant effect on the electrical performance and power generation efficiency of photovoltaic (PV) modules. It is an important parameter for PV system modeling, performance evaluation, and maximum power point tracking. The analysis shows that the results of physics-based methods always change with seasons and weather conditions. It is difficult to measure all the needed variables to build the physics-based model for the calculation of operating temperature. Due to the above problem, the paper proposes an online method to calculate operating temperature, which adopts the back propagation artificial neural network (BP-ANN) algorithm. The comparative analysis is carried out using data from the empirical test platform, and the results show that both the BP-ANN and the support vector machine (SVM) method can reach good accuracy when the dataset length was over six months. The SVM method is not suitable for the temperature modeling because its computing time is too long. To improve the performance, wind speed should be taken as one of the models’ input if possible. The proposed method is effective to calculate the operating temperature of silicon-based solar modules online, which is a low-cost soft-sensing solution

Flexible operation of a CHP‐VPP considering the coordination of supply and demand based on a strengthened distributionally robust optimization

Abstract Due to the generation variability, the growing capacity of renewable energy has posed unprecedented challenges to ensure the security of power system operation. Here, a two‐stage strengthened distributionally robust optimization (DRO) scheme is proposed for theself‐scheduling of a combined heat and power virtual power plant (CHP‐VPP) over a coupled electric power network (EPN) and district heating network (DHN). The CHP‐VPP operator maximizes its profits in the day‐ahead market and minimizes its cost in the real‐time market under the worst‐case realization of the uncertainties. Instead of assuming that the uncertainties follow known probability distributions or confidence bounds, a strengthened ambiguity set based on moment information and Wasserstein metric is built to provide more accurate characterizations of the true probability distribution of uncertainties. In addition, in order to enhance the flexibility of the system, a HOMIE model considering indoor activities and outside temperatures of each building is built to satisfy the comfortable indoor temperature. To make the whole problem tractable, linearisation and duality theory are adopted, and then a tailored column‐and‐constraint generation algorithm is developed to solve the problem. The validity and applicability of the strengthened DRO scheme are verified by an IEEE 33‐bus EPN and 14‐node DHN

Optimal Multi-Mode Flexibility Operation of CHP Units with Electrode Type Electric Boilers: A Case Study

With the in-depth development of flexibility retrofit in combined heat and power (CHP) units, the unit commitment mode of energy supply equipment in CHP plants is more flexible. This paper presents a multi-mode flexible operation method for CHP plants with electrode electric boilers. Firstly, a simulation model of the operation characteristics of each unit in different operation modes is established, and the corresponding features of electrical and thermal outputs are obtained. Subsequently, a decision-making model of the unit commitment mode of energy supply equipment is set up, and the selection rules of the unit commitment mode of the unit under low heat load, medium heat load, and high heat load are achieved. Finally, under different unit operation combinations, a plant-level optimum load dispatch model is obtained, and the actual operating data of the CHP plant is used for optimization and comparison analysis. The results show that compared to the unit commitment mode of high back pressure and low-pressure cylinder cutting-off (HBP + LPCC), the unit commitment mode of high back pressure and extraction heating (HBP + EH) has more room for energy-saving optimization. Under the premise of safe and reliable operation, the high back pressure (HBP) unit can be loaded as much as possible. While in the combined operating of HBP + EH, the energy-saving space for optimized load dispatching is not large, so a fixed proportion of the electrical load may be considered; under the auxiliary service subsidy policy, the input power of the electric boiler can be appropriately increased; the greater the heat load of the whole plant, the more pronounced the energy-saving effect of optimum load dispatch

Optimal Multi-Mode Flexibility Operation of CHP Units with Electrode Type Electric Boilers: A Case Study

With the in-depth development of flexibility retrofit in combined heat and power (CHP) units, the unit commitment mode of energy supply equipment in CHP plants is more flexible. This paper presents a multi-mode flexible operation method for CHP plants with electrode electric boilers. Firstly, a simulation model of the operation characteristics of each unit in different operation modes is established, and the corresponding features of electrical and thermal outputs are obtained. Subsequently, a decision-making model of the unit commitment mode of energy supply equipment is set up, and the selection rules of the unit commitment mode of the unit under low heat load, medium heat load, and high heat load are achieved. Finally, under different unit operation combinations, a plant-level optimum load dispatch model is obtained, and the actual operating data of the CHP plant is used for optimization and comparison analysis. The results show that compared to the unit commitment mode of high back pressure and low-pressure cylinder cutting-off (HBP + LPCC), the unit commitment mode of high back pressure and extraction heating (HBP + EH) has more room for energy-saving optimization. Under the premise of safe and reliable operation, the high back pressure (HBP) unit can be loaded as much as possible. While in the combined operating of HBP + EH, the energy-saving space for optimized load dispatching is not large, so a fixed proportion of the electrical load may be considered; under the auxiliary service subsidy policy, the input power of the electric boiler can be appropriately increased; the greater the heat load of the whole plant, the more pronounced the energy-saving effect of optimum load dispatch

An evaluation method for green logistics system design of agricultural products : a case study in Shandong province, China

Recently, the environmental issue caused by logistics of agricultural products has attracted a great deal of attention. In order to solve the problem, much of work focuses on green logistics to decrease environmental pollution. However, the green logistics evaluation system of agricultural products is insufficient. Therefore, establishing a reasonable green logistics evaluation system for agricultural products plays a key role in the development of green agricultural products. In this work, domestic and international environmental factors which affect the development of the green logistics of agricultural products are analyzed based on reduction, reuse, and recycling principle of circular economy. In addition, a series of evaluation indicators for green logistics of agricultural products are developed. A fuzzy analytic hierarchy process method is proposed to make a comprehensive evaluation for green logistics of agricultural products based on evaluation indicators. The method combined analytic hierarchy process and fuzzy theory, where a fuzzy transformation operator is introduced. The proposed method is applied for decision-maker in view of knowledge management. In order to verify the applicability of approach, the approach is applied to green logistics of Shandong agricultural products.Published versio

Design and Control for WLR-3P: A Hydraulic Wheel-Legged Robot

The robot used for disaster rescue or field exploration requires the ability of fast moving on flat road and adaptability on complex terrain. The hybrid wheel-legged robot (WLR-3P, prototype of the third-generation hydraulic wheel-legged robot) has the characteristics of fast and efficient mobility on flat surfaces and high environmental adaptability on rough terrains. In this paper, 3 design requirements are proposed to improve the mobility and environmental adaptability of the robot. To meet these 3 requirements, 2 design principles for each requirement are put forward. First, for light weight and low inertia with high stiffness, 3-dimensional printing technology and lightweight material are adopted. Second, the integrated hydraulically driven unit is used for high power density and fast response actuation. Third, the micro-hydraulic power unit achieves power autonomy, adopting the hoseless design to strengthen the reliability of the hydraulic system. What is more, the control system including hierarchical distributed electrical system and control strategy is presented. The mobility and adaptability of WLR-3P are demonstrated with a series of experiments. Finally, the robot can achieve a speed of 13.6 km/h and a jumping height of 0.2 m