Using water cascade analysis to synthesize water use network in batch process

Batch processes are relevant to a wide variety of industries in chemical processes. In batch operations, water sources are almost not directly reused/recycled in process sinks without considering time constraints and storage tanks. However, storage tanks are usually expensive and thus a cost-effective water system has to be synthesized. Rescheduling the water network can contribute to reducing the cost of storage tanks by reducing their number and capacity. In the current research work, a goal programming is used to reschedule the water network in batch processes considering the time and storage tanks. A Mixed Integer Non-Linear Program model is introduced using the Lingo optimization program. This model is used to optimize multiple objectives, which are freshwater usage, wastewater discharge, the number and capacity of tanks, the degree of shifting streams, and the total cost of the water network. Three case studies are presented in this study to demonstrate the effectiveness of the proposed procedure, considering both single and multi-contaminants problems. The results of the first case study show a reduction in the network cost and the freshwater flowrate by 26.4% and 42%, respectively. Regarding the rescheduled water network results of the second case study, the cost is reduced by 24.6% and the freshwater flowrate is decreased by 21.8% with no requirement of storage tanks. The third case study highlights the model’s applicability to multi-contaminants problem, revealing a 15.1% cost reduction and a 25.7% decrease in freshwater flow.

In the production process of viscose staple fiber, a large amount of freshwater, steam and desalinated water will be consumed, and a large amount of acidic and alkaline wastewater will be generated, bringing great pressure on water resource and environmental protection. In this paper, the water using system of a viscose staple fiber plant in northwestern China is studied. The key constraints for water using in this system are pH, oxygen demand (COD) and suspended solid (SS). Since pH and COD are non-conserved quantities, their constraints are property-based. So, the optimization of the water network needs to be carried out from both conventional water system integration and property integration. In this paper, the Mathematical Programming method is used to solve the optimization problem. By analyzing the various constraints and taking the corresponding integration methods, the mathematical model is constructed to target the minimum freshwater flowrate, the minimum regenerated water flowrate and relevant parameters. The optimized network can reduce the freshwater consumption 93.1 m³/h and the wastewater discharge 131 m³/h, achieving obvious water-saving and emission reduction effects.

Control and reduction of leakage in water distribution networks are very important due to limitation of drinking water resources. Water distribution networks are currently designed based on hourly peak consumption. Variation of the hourly water consumption causes the pressure variation and increase in water leakage. If household storage tanks are used in buildings, the water networks can be designed based on daily peak consumption, resulting in considerable reduction in the hourly flow variation. In the present study, the effect of domestic water storage tanks on the leakage level of water networks has been studied using water hydraulic simulation. The results showed that the use of household tanks can significantly reduce the leakage level for water networks under operation. For the studied networks, the average leakage reduction level were 31% and 67% for tanks on the roof and in the parking lot, respectively. The results also showed that the branched or looped plans of water network have no significant effect on the amount of leakage reduction. Results of this study can be used in developing new design methods for water distribution networks aiming pressure management and control of the leakage level.

Software Program of Water and Wastewater Network Optimization Was Provided and Was Applied in Petrochemical Enterprise. a New Water System Optimization Method Was Based on Mass Transfer Model of Water Pinch Technology, Evry Operation Used Matched Water of Circle Water and Fresh Water in Turn. Judgement Basis of Operation Sequence and Theoretical Basis of Selection of Water Source Was Put Forward. the Water Network Optimization Program of Matlab Language Was Edited and Applied in a Petrochemical Enterprise. the Result Showed that the Fresh Water Reduction Was 38.31% when the Optimization Method Was Used in one Water System Contaminanted by Sulfur with Nine Operations.

A model-based approach for simultaneous water and energy reduction in a pulp and paper mill

The Water Cascade Analysis (WCA) technique was used to identify opportunities for reduction in freshwater usage as well as wastewater generation and to assist in the retrofit of an existing paper mill water distribution network. This procedure involves three key steps; i.e., a global analysis of the present water distribution and consumption, setting the baseline minimum water targets using WCA technique and retrofit of water network to achieve the minimum water targets. Notwithstanding the extensive water recycling currently employed in the paper mill, this study identified a potential scope of reducing 13.3% freshwater and 13.3% wastewater. Water reduction represents a total potential annual savings of RM 595,232, taking into account the raw water and wastewater treatment costs, pumping and chemical costs.

Town of Krosno is supplied with water by 3 intakes: Sieniawa, Iskrzynia and Szczepańcowa. After the treatment water flows in water mains to the water network in Krosno. The aim of his paper is qualitative risk analysis of the water main Sieniawa failures. The consequences of the failure: pressure value in the network and its duration, were described for different conditions of failures: time of failure, water demand and water storage tanks initial filling. For simulations of pipe failure water network model made in Epanet 2 program was used. The model was verified both during operation of water network and during the failure, where field data were used. The results of the simulations are corresponding to observations made during the real failures. Negative consequences appear only after emptying the water storage tanks, it results from two features of the storage tanks: they stabilize pressure in the network and for some time can provide water to the network. The time of emptying the storage tanks varies according to water demand their initial filling, it is at least 3 hours. During this time the are no sign of failure. When the storage tanks are empty reduction of pressure an shortage of water are observed on prevailing area of Krosno.

Assessing the potential of government regulation in the water supply and sanitation sector

A new methodology for the synthesis of an optimum flexible water networks

This paper discusses an initial trial of parabolic through solar collector (PTSC) in Gunung Kidul, Yogyakarta, Indonesia. The PTSC system consists of a solar collector, oil pump, and storage tank. The collector uses a parabolic type which consists of a concentrator, absorber and tracking system. The trial was conducted to determine the PTSC performance, such as collector capacity and storage capacity, and system efficiency. Solar intensity, temperature inlet and outlet of the working fluid in the storage tank was measured to determine PTSC performance. The collector has 3.5 m and 36 m of aperture width and parabolic length, with 1 m of focal distance. Palm oil is used as the working fluid and stored in a storage tank with a single type. The trial was carried out for two days with 30 minutes of interval time from 8:30 to 15:00 per day. The trial result shows that PTSC system produced 28.16 kW and 2.26 kW of collector capacity and storage capacity, and 8% efficiency on the first day. On the second day, PTSC produced 25.49 kW and 1.88 kW of collector capacity and storage capacity, and 7.4% efficiency.

Optimum synthesis of an electrodialysis framework with a Background Process II: Optimization and synthesis of a water network

In a chemical plant, even if an explosion occurs in a storage tank that handles flammable materials, the minimum separation distance is applied in a way to prevent chain explosion. This is because when an explosion occurs in a storage tank, thermal radiation affects nearby process equipment and causes a chain explosion. The separation distance between storage tanks and process equipment in a chemical plant depends on the global engineering guidelines PIP (Process Industry Practice) PNE00003 and GAPS (Global Asset Protection Services) GAP.2.5.2. However, there is a limitation in the global engineering guidelines that provide only a consistent separation distance according to the item types without considering the storage capacity and climatic conditions around the storage tank. This study analyzed the distance of thermal radiation (up to 37.5 kW/m2) according to the capacity of ethylene storage tank and climatic conditions by utilizing the Phast (DNV GL), which is widely used as a tool for quantitative risk analysis. The accident scenario was applied using the U.S. EPA (Environment Protection Agency)’s worst leakage accident scenario, considering climate variables, air temperature, wind speed, and atmospheric stability. In the simulation, atmospheric stability did not affect the radius of thermal radiation. Moreover, the thermal radiation tended to increase with increase in wind speed in the ambient condition and winter, but not in summer. Because both PIP PNE00003 and GAP.2.5.2 yield consistent separation distances without considering storage capacity and weather conditions, quantitative risk analysis of the results of thermal radiation is necessary to ensure safety.

Water and nitrogen are the main limiting factors affecting agricultural production in arid and semiarid regions. Therefore, improving the efficiency of these factors is very important. The method of fertilizer application is affecting water and fertilizer use efficiency. The objective of this study was to investigate the effect of furrow fertigation on fertilizer use efficiency (FUE), water use efficiency (WUE), and corn yield. A field experiment was carried out in furrows which have 165m length and 0.006 (m/m) slope in Karaj. The corn Hybrid 370 double-cross was planted on June 2008. A factorial design based on randomized complete block design with 4 replicates. Four levels (0, 60, 80 and 100%) of the recommended fertilizer value and four levels (60, 80, 100, and 120%) of the irrigation water requirement were applied. These 16 treatments were compared with traditional fertilizer application method. Fertilizer treatments were accomplished in four critical stages of the growth (before cultivation, in seven leaves stage, shooting stage and Flowering stage) for fertigation treatments and two stages (before cultivation and seven leaves stage) for the traditional method. Results showed that effects of levels of different water and fertilizer on yield component were significant. Water use efficiency (WUE) was significantly affected by nitrogen rate. On the other hand, water treatments significantly affected fertilizer use efficiency. Increasing fertilizer increased water use efficiency. Increasing water levels to 100% of ETC resulted in increasing fertilizer use efficiency. Highest yield was obtained from the full irrigation treatments (W100%). Albeit the difference among W120%, W100% and W80% was not significant (P=0.05), because W100% was always higher than W120%, treatment of W80% recommends as optimum water level for arid and semi arid region. The maximum and minimum WUE was 2.24 and 0.66 (kg/m3) in W80%N100% and W100%N60%, and The maximum and minimum FUE was 29.85 and 8.52 (kg/kg) in W100%N100% and traditional method, respectively. Key words: Fertigation, Fertilizer use efficiency, Productivity, Corn

Green roof storage capacity can be more important than evapotranspiration for retention performance

New completion time algorithms for sequence based scheduling in multiproduct batch processes using matrix