Shanying Hu

Evaluating waste treatment, recycle and reuse in industrial system: an application of the eMergy approach

This paper deals with the application of emergy analysis of industrial systems in considering wastes. Making process system engineering decisions that are ecologically conscious requires emergy analysis of both industrial and ecological processes. The traditional emergy analysis methods of a natural ecological system usually do not consider the impact of wastes. This paper considers the impact of wastes and improves existing emergy analysis methods for industrial system. A new index of sustainability for industrial processes is presented.

Modeling and optimization of herb leaching processes

Abstract The mathematical model of the herb leaching process is presented in this paper based on the mass transfer principle. At the same time, the process system engineering methodology is applied to study the herb leaching process in order to improve the operating conditions and the yields of effective compounds. The modification parameters in the model are predicted using parameter estimation technique to make the model calculated values agree with the experimental data. A case study for the angelica leaching process was presented. The simulation results show a perfect matching between the calculated values with the experimental data. The effects of different operating conditions on the yield of effective compounds in the herb leaching process are also investigated applying the simulation study. Furthermore, the optimal operating condition is obtained to maximize economic profit. The results also indicate the extended application prospects of simulation and optimization technology in the modernization of Chinese traditional herb leaching production.

Development of an expert system for synthesis of heat exchanger networks

Abstract A knowledge-based system for aiding in the construction of practical heat exchanger networks called SPHEN is presented in this article. The created network configurations feature low utility cost, low capital investment, rather stable heat recovery during operation and rational distribution of pressure drops among the network branches. SPHEN consists of four component parts: network construction, simulator, flowsheet diagram generation and users feedback subsystem. So SPHEN is characterized by its hybridity, reflected in knowledge representation and abstraction,solving methods and implementation languages. The hybrid system is implemented through disk files and data files connecting different parts into one working space. An example of redesigning an energy recovery network of a large-scale crude oil unit is illustrated and the results obtained are successful.

Three-distribution-parameter general model for reactor network synthesis

Abstract Reactor network synthesis has attracted more and more attentions especially under the increasing stress on the environment problem. Recent advances have been made chiefly in approaches for superstructure optimization as well as reactor network targeting concept. In this paper, a three-distribution-parameter general model for reactor network synthesis is proposed. The three distribution parameters are side feeding, recycling and bypassing distribution parameters respectively. Because they can greatly influence the concentration and residence time profile within the reactors, which enable the proposed general model to be compact and efficient. Based on this general model, the reactor network synthesis problem can be formulated as an optimization problem. By orthogonal collocation on finite element discretization strategy, the original optimization model is transformed into a NLP problem. After optimization, the reactor type with varying maximum mixing to minimum mixing and configuration including series and parallel connection in the reactor network can be directly decided according to the optimal solution of distribution parameters. Three examples are studied and discussed. From the results, it can be concluded that the side feeding, recycling and bypassing strategy can give a comprehensive reflection of optimal characteristic of the reactor network under various reaction kinetics and the objective formulation, and easy to be used to gain practical network.

From Production to Consumption: A Coupled Human–Environmental Nitrogen Flow Analysis in China

Anthropogenic inputs of reactive nitrogen (Nr) provide sufficient food, energy, and industrial products to meet human demands; however, only a fraction of Nr is consumed as food and nonfood goods, and the rest is lost to the environment and negatively affects ecosystems. High-resolution studies of nitrogen flows are invaluable to increase nitrogen use efficiencies and reduce environmental emissions. In this study, a comprehensive substance flow analysis of nitrogen for China in 2014 is presented. Based on the conceptual framework, which highlights the key roles of human drivers, the analysis of the synthetic ammonia supply and demand balance shows that 75% of ammonia is used for agricultural purposes. Moreover, the life cycle analysis of food nitrogen shows that human food consumption accounts for approximately 7% of the total Nr inputs. A quantitative analysis of pollutant emissions shows that industrial and crop production are the main sources of atmospheric emissions, while livestock farming and crop production are the main sources of water emissions. Finally, we investigate four scenarios (efficiency improvement, high recycling rate, nitrogen oxide emission reduction, and a combined scenario) and provide relevant policy recommendations (large farm size, standardized agricultural production model, flue gas denitration, etc.) for improving nitrogen management practices.

A Study of the Sustainable Development of China’s Phosphorus Resources Industry Based on System Dynamics

Abstract As a non-renewable ore, phosphate rock is a very important strategic resource. However, in the process of the exploitation and utilization, there are severe waste and environmental pollution problems which are disadvantageous to the sustainable development of phosphorus resources. In order to promote the sustainable development of China’s phosphorus resources industry, this research proposes a system dynamics model with two sub-models for thermal phosphoric acid and wet phosphoric acid separately, considering to the actual situation of regional phosphorus resources industry. This model focuses on industrial, financial, technological and environmental policies for the development of phosphorus resources industry, such as phosphorus resources exploitation, product structure adjustment, waste management and other policies. To find the optimum policy combination of sustainable development, the model which employs resource productivity, economic benefits, ecological efficiency and social satisfaction as objects, explores development situations of phosphorus resources industry and assesses the impacts of the policies by comparative policy scenarios. Results show that under the condition of excess capacity, optimization of phosphate fertilizer product portfolio is more advantageous compared with capacity expansion to increase production value of phosphorus chemical industry. And the combination of total consumption control policy of phosphate rock and acts to promote technical progress improves resource productivity. The implementation of waste recycling policies is conducive to improve continuously the eco-efficiency, and is not conducive to increase economic benefit due to more investment cost. Finally, this study indicates that an effective combination of total consumption control policy, product structure adjustment and appropriate environmental protection will be beneficial to the sustainable development of phosphorus resources industry. In addition, it contributes not only to the conservation of natural resources, but also to a reasonable disposition of the investment which can promote technological progress in industrial weak links. Moreover, the results can provide relevant references for policy makers to make appropriate decisions.

Reaction path synthesis for a mass closed-cycle system

Abstract With more and more severe problems of environmental pollution, the chemical industry entails the consideration of minimum environmental impact when synthesizing reaction path. In this paper, a systematic method for reaction path synthesis is described in which undesirable chemicals are cycled to realize zero avoidable pollution. A novel concept of simple stoichiometric reactions (SSRs) is introduced to determine simple stoichiometries between raw materials, probable intermediate chemicals and co-products and to form a reaction path network. Promising reactions are identified by an optimization program from this network. Case studies are discussed to illustrate the proposed method.

Delayed sampling approach to stochastic programming in chemical processes

Abstract In this paper, a new stochastic programming approach is presented to address chemical process optimization problems under uncertainty. The novel algorithm, named as delayed sampling approach, solves an equivalent deterministic optimization model transformed from the stochastic optimization problem between two stochastic simulations. The sampling numbers are reduced considerably and the computational burden is then alleviated remarkably. A complex crude distillation unit is modeled and optimized using the new stochastic approach. Savings of up to 80% in CPU time has been achieved without significant loss of solution precision compared to the conventional stochastic optimization method.

The trends of aquacultural nitrogen budget and its environmental implications in China

The rapid development of aquaculture has sustained aquatic food production but has also led to a host of environmental problems, ranging from eutrophication of aquatic ecosystems to global acidification. China has become the world’s largest producer and consumer of aquaculture products. Nitrogen is an essential nutrient in aquaculture ecosystems, and the quantitative environmental fate and impact of nitrogen during aquaculture processes have notable environmental consequences but have received little attention. Here, we established a nitrogen cycling model for China’s aquaculture ecosystem to investigate the creation and fate of reactive nitrogen over a decadal time scale. A nitrogen balance analysis showed that reactive nitrogen input in the aquaculture ecosystem increased from 9.43 Tg N yr−1 in 1978 to 18.54 Tg N yr−1 in 2015, while aquaculture production increased from 0.034 to 1.33 Tg N yr−1 during the same period. The environmental fate analysis showed that nitrogen emissions, accumulation, sediment deposition, and export into the oceans increased by 9.05-fold, 0.24-fold, 9.04-fold, and 2.56-fold, respectively. Finally, we investigated four scenarios representing different consumption levels of aquatic products and provided policy recommendations (larger aquaculture size, standardized aquaculture production model, nutritional element management and balanced dietary structure, etc.) on improved management practices in aquaculture ecosystems.

Development of a management information system for an eco-industrial park

Abstract With the development of Eco-Industry, Management Information System (MIS) comes to become an important part of Eco-industrial Parks. Based on the concept of Eco-industrial Park, a MIS is developed through the processes of database and function modules design, using the Browser/Server method. A mathematic model is addressed for analyzing pollution sources in a river. The quantitative evaluating index presented in this paper can be used to indicate which environments cause the pollution accident. A case study shows the effectiveness of the model.