Interplant Water Integration Research Articles

Centralised Water Reuse Exchange in Eco-Industrial Park Considering Wastewater Segregation

Water is a vital resource for sustainable economic and social development. Water over-abstraction is one of the main threats to the environment. Most of the past works considered intra- and inter-plant integrations, in which reused water has been exchanged within a single plant before being transported to the centralised network. Excess wastewater that would be sent to the centralised system likely had the same quality and segregation was not necessary. For this study, only inter-plant and indirect water integration is considered. Water data generated by industries are considered to be directly transported to the centralised network with different wastewater qualities. This paper presents a mathematical programming formulation for centralised water reuse exchange in Eco-Industrial Park (EIP) considering wastewater segregation before centralised treatment with a single contaminant. The mathematical formulations are based on a superstructure that segregates wastewater based on quality before being transported to the centralised utility provider using water header. The main objective is to minimize freshwater consumption in the industry by utilizing regenerated water from the centralised utility provider. The model is coded and solved by using the General Algebraic Modeling System (GAMS) software with non-linear programming (NLP). The model is tested with a case study of three scenarios, each with different numbers of water headers. The results obtained show a significant freshwater saving of 98 % from the inter-plant indirect water integration in Scenario 3, which had the highest number of water headers and regeneration units.

A superstructure model for indirect inter-plant water integration for selecting the optimum single-pass and partitioning regenerators

Water scarcity and stricter regulations on industrial effluents have led to a different view of water use. Water recycling / reuse is the most common technology used to reduce water and wastewater. The integration of multiple industrial plants, known as the inter-plant integration, has gained a great attention in recent years. Inter- plant water integration is a new technology that can be applied to water integration. This technology can be used to reduce water consumption and water discharge of various water networks in eco-industrial plants. This can be achieved directly or indirectly through the use of regenerators. In this work, a superstructure model for the indirect inter-plant water integration is proposed, for selecting the optimum regenerators of single pass and partitioning regenerators. Mixed integer non-linear program (MINLP) was formulated and solved for optimum solution. A literature case study is used to verify the effectiveness of the proposed model. The results showed that there was a significant decrease in the fresh and the discharge water of the integrated plants.

Optimization of Inter-Plant Water Network Design Involving Multiple Contaminants

Minimization of freshwater consumption and wastewater generation are being critical concerns in the process industry due to the scarcity in freshwater supply, the increase of freshwater and effluent treatment costs and stricter regulations. One of the efficient ways to reduce freshwater consumption in the process is by recycling and/or reusing wastewater that is generated by the process or utility after being treated to acceptable limits. This work presents the development of a systematic approach for synthesizing indirect inter-plant water network integration with centralized regeneration system involving multiple contaminants. In this approach, water reuse prospects were analysed within individual plants and between different plants via inter-plant water integration possibilities. The water network problem is formulated as a mixed integer nonlinear programming (MINLP) based on the water network superstructure and is solved using GAMS optimization software. The applicability of the proposed approach is illustrated using a wafer manufacturing process plants case study. At the end of this study, significant reductions of freshwater consumption and wastewater generation have been achieved, showing the effectiveness of the proposed approach. The results show that the freshwater consumption and wastewater generation reduced about 47.61% and 53.48% respectively.

Industrial park water system optimization with joint use of water utility sub-system

This paper develops a new superstructure-based methodology for the synthesis of industrial park water system. The model includes sub-system of water utility, water-using and wastewater treatment for each single plant. It considers the single and inter-plant water integration and sharing strategy of water utility sub-system. The objective function is to minimize the partial annualized cost of the industrial park water system. Results show that all plants (i.e. Plants 1 and 2) in the industrial park can share a desalted water station in Plant 2. Because the water production ratio of desalted water station in Plant 2 is lower than that of Plant 1 and it indicates that the desalted water station in Plant 2 is with high efficiency to produce the same quality of desalted water. The cost can be decreased from 1.5 × 108 CNY/y (preliminary design) to 8.42 × 107 CNY/y (inter-plant optimization) with the flowrate reduction of water resource from 2694.954 t/h to 2045.184 t/h. It achieves the water minimization and effective joint use of water utility system.

Total site centralised water integration for efficient industrial site water minimisation

Water is used in process industry for a wide range of applications. Water minimisation has received growing attention due to stricter environmental regulations and scarcity of quality water. Rising price of fresh water and cost of wastewater treatment, as well as the relation with the energy (generating emissions) needed for preparing and supplying water, have created an urgent need for efficient water utilisation, especially in the industrial sector. Demand for clean water has been rapidly growing also in the commercial and domestic sector, and very substantially in the agricultural sector. In some regions, water has become a strategic commodity that is even more important than energy. Numerous research works have been performed on Total Site Water Integration (also known as Interplant Water Integration in some papers). However, a superstructure that considers all possibilities of water exchange among sources and demands in industrial sites or a region, are practically challenging to implement since most plants prefer to keep their data and processes confidential. The cost of piping and pumping can be very high due to the need to transfer water across complex industrial water networks. In this study, the option of using centralised headers managed by a third party is explored for a simpler and easy to manage water reuse and recycling among plants. Two centralised water reuse headers with different wastewater quality range, located along a set of plants are proposed. A new Pinch Analysis methodology known as Total Site Centralised Water Integration (TS-CWI) to target the minimum freshwater requirement and wastewater generated resulted from the integration of plants with this centralised water reuse headers are presented. The methodology is illustrated with a case study with 55.1 % of reduction of freshwater requirement and 54.7 % of reduction of wastewater generated.

Automated targeting technique for indirect inter-plant hydrogen integration

The increase of hydrogen demand has been one of the focal point recently. Indirect inter-plant hydrogen integration (IPHI) is a new issue for reducing hydrogen consumption and hydrogen discharge, in which hydrogen networks for different plants are integrated indirectly through centralized partitioning regeneration unit where hydrogen is regenerated for further reuse/recycle. This work is an extension of the automated targeting technique that was developed for single hydrogen network and the automated targeting that was developed for inter-plant water integration. The concentration cascade model has been developed to optimize hydrogen networks through partitioning regeneration unit such as pressure swing adsorption (PSA) or membrane separation. Two case studies from literature are studied to illustrate the applicability of the proposed model.

A synthesis approach for industrial city water reuse networks considering central and distributed treatment systems

This paper presents an optimization approach to the development of macroscopic networks for water integration within industrial cities. The methodology considers various strategies for industrial wastewater reuse amongst different processing facilities that operate within the city. Two different scenarios for the placement of intermediate water treatment interceptors are considered: (1) on-site ‘decentralized’ water treatment within each plant, and (2) off-site ‘centralized’ water treatment that can be shared amongst a cluster of existing industrial plants. The overall objective is to develop cost-efficient water networks that can attain effective interplant water integration scenarios, whilst considerably reducing freshwater consumption and wastewater discharge where appropriate. The optimization model has been formulated as a Mixed Integer Non-Linear Program (MINLP), and accounts for pressure drops associated with piping across all individual source-interceptor-sink allocations. Additionally, a representation that accounts for constrained water transport was adopted, in which designated corridor regions within an industrial city are utilized for the planning of economical pipeline networks that achieve desirable water allocation strategies. In doing so, shortest routing options were obtained between water sources, sinks, and treatment interceptors, according to a given industrial city layout. A case study that considers various different scenarios in terms of contaminant information and piping connectivity is presented to illustrate the proposed approach.

A Mathematical Model for Water Network Synthesis Involving Mixed Batch and Continuous Units

This paper presents a mathematical model for the synthesis of water networks for systems consisting of process units of different operation modes, namely, truly batch, semicontinuous, and continuous units. By treating a continuous process as a special case of a semicontinuous process, the original problem becomes to synthesize a batch water network comprised of truly batch and semicontinuous units operated cyclically with a fixed schedule. The model is formulated as a mixed-integer nonlinear program based on a unit-tank superstructure including all possible network interconnections. Three modified literature examples are used to illustrate the proposed approach, with both in-plant and interplant water integration analyzed.

Global optimization in property‐based interplant water integration

This article presents a new global optimization method for the interplant water integration based on properties to characterize streams with numerous components. The problem is formulated as an mixed‐integer non‐linear programming (MINLP) model based on a superstructure that involves all possible options of interest (i.e., reuse and recycle in the same and to other plants and a set of shared treatment units). This formulation exhibits multiple local minima, and to overcome this problem, this article proposes effective branching rules in addition to two new reformulations for the upper bound (integer feasible solution) and the lower limit (relaxed solution), which are incorporated into a spatial branch and bound procedure to handle the bilinear terms in the model. The objective consists in finding the configuration with the minimum total annual cost. Results show that the global optimal solution (involving significant reductions in the fresh water consumption) is reached in few iterations and short central processing unit (CPU) time. © 2012 American Institute of Chemical Engineers AIChE J, 59: 813–833, 2013

A note on an extended fuzzy bi-level optimization approach for water exchange in eco-industrial parks with hub topology

In our previous paper, a fuzzy bi-level programming model was developed to determine optimal interplant water integration networks in eco-industrial parks (EIPs). This approach allowed the appropriate incentive mechanisms, in the form of fresh water and effluent fees as well as water reuse subsidies, to be optimized from the perspective of the EIP authority. This work extends the original mathematical model by modifying the role of the EIP authority to include water regeneration and redistribution via a centralized hub. The resulting fuzzy bi-level programming model may then be solved to yield a “satisficing” solution that reflects a reasonable compromise between the EIP authority's desire to minimize fresh water usage, and the participating companies’ desire to minimize costs. A case study is used to illustrate the modeling approach.

Analysis of inter-plant water integration with indirect integration schemes through game theory approach: Pareto optimal solution with interventions

Fresh resources such as water can be conserved through effective reuse/recycle among several industrial plants with inter-plant water integration (IPWI) scheme. Two types of IPWI schemes exist, i.e. direct and indirect integrations. This article focuses on the latter, where the water networks are integrated indirectly through a centralised utility hub (CUH). The CUH acts as a buffer to collect water from different networks, where water is intercepted for further reuse/recycle (regeneration) and/or for final environmental discharge. A recent developed game theory approach is extended for the use of indirect IPWI schemes in this study. Besides, intervention by an eco-industrial park (EIP) authority is included in the analysis to investigate the influence of incentive on the participation of water network in the IPWI.

Design of inter-plant water network with central and decentralized water mains

This paper presents a mathematical model for the inter-plant water integration of an industrial complex that consists of a number of process plants. Opportunities for water reuse/recycle across plants are exploited. In particular, a novel integration scheme is proposed, where central and decentralized water mains are placed to interconnect the water-using units of the individual plants. The principal advantage of using water mains is to improve the overall network practicability. The model formulation is based on a series of superstructures, and the design problem is optimized according to two objectives that include the minimization of fresh water consumption and total annualized cost. An example is solved to illustrate the proposed integration scheme and approach.

Segregated targeting for multiple resource networks using decomposition algorithm

AbstractA generalized decomposition technique is presented for determining optimal resource usage in segregated targeting problems with single quality index (e.g., concentration, temperature, etc.) through pinch analysis. The latter problems are concerned with determining minimal resource requirements of process networks characterized by the existence of multiple zones, each consisting of a set of demands and using a unique external resource. However, all the zones share a common set of internal sources. The decomposition algorithm allows the problem to be decomposed into a sequence of subproblems, each of which can in turn be solved using any established graphical or algebraic targeting methodology to determine the minimum requirement of respective resource. This article presents a rigorous mathematical proof of the decomposition algorithm, and then demonstrates its potential applications with case studies on carbon‐constrained energy sector planning, interplant water integration, and emergy‐based multisector fuel allocation. © 2009 American Institute of Chemical Engineers AIChE J, 2010

Game theory approach to the analysis of inter-plant water integration in an eco-industrial park

Industrial water conservation is an important adaptation to the effects of climate change. In addition to water conservation within individual plants, wastewater can be reused/recycled among different companies through inter-plant water integration (IPWI) schemes. Such schemes are based on the concept of industrial ecology and industrial symbiosis, and can be used to achieve greater water savings than when water conservation is implemented in individual companies separately. However, in IPWI, each participating company seeks to maximise its own benefits. In the absence of centralised authority dictating the terms of water integration schemes, conventional modelling techniques are not appropriate. This paper shows how a game theory-based approach can be used to analyse the interaction of participating companies in an eco-industrial park seeking to develop an IPWI scheme.

Automated targeting for inter-plant water integration

Apart from in-plant water recovery, inter-plant water integration (IPWI) offers another promising mean for the reduction of fresh water and wastewater flowrates for process plants. This paper extends the automated targeting technique that was developed for single water network into IPWI. This optimisation-based technique is based on the concept of pinch analysis, which enables the setting of various network targets prior to detailed design. The automated targeting technique is formulated as a linear programming model for which global optimum is guaranteed. The proposed technique is demonstrated using several industrial and literature examples.

Synthesis of Direct and Indirect Interplant Water Network

To date, most work on water network synthesis has been focusing on a single water network. The increase of public awareness toward industrial ecology has inspired new research into interplant water integration (IPWI). In this context, each water network may be grouped according to the geographical location of the water-using processes or as different plants operated by different business entities. Water source(s) from one network may be reused/recycled to sink(s) in another network. In this work, two different IPWI schemes, that is, “direct” and “indirect” integration are analyzed using mathematical optimization techniques. In the former, water from different networks is integrated directly via cross-plant pipeline(s). A mixed integer linear program (MILP) model is formulated and solved to achieve a globally optimal solution. In the latter, water from different networks is integrated indirectly via a centralized utility hub. The centralized utility hub serves to collect and redistribute water to the indiv...