Synthesis Of Resource Conservation Networks Research Articles

Synthesis of Resource Conservation Networks with P-Graph Approach—Direct Reuse/Recycle

The need for climate change adaptation in industry has led to intensified research in industrial resource conservation, as well as waste reduction, to enable sustainable operations to be achieved even under conditions of declining water resources. Such sustainability initiatives can be facilitated using the systematic approach of process integration (PI). Of particular interest are resource conservation network (RCN) problems, which have been solved using pinch analysis or mathematical programming methods. On the other hand, other process system engineering (PSE) tools such as the process graph (or P-graph) framework offers potential alternative approaches to RCN problems. To date, P-graph methodology has been used for various process network synthesis (PNS) problems; however, no RCN synthesis applications have been reported thus far. This paper presents a novel implementation of P-graph for RCN synthesis. In addition to the inherent computational efficiency of its algorithms, P-graph allows the elucidation of optimal and near-optimal solutions, a feature which is potentially useful for practical decision-making. Capital and operating cost considerations can be incorporated easily. In this paper, direct reuse/recycle scheme is applied for in-plant RCN and inter-plant RCN (IPRCN).

A two-stage optimization approach for the synthesis of resource conservation networks involving interception units

This study presents a mathematical optimization model for resource conservation network (RCN) synthesis that includes interception units within the structure of the network. RCNs are the one of the most efficient designs for minimizing fresh water consumption, wastewater generation, and operation cost. Interception units (single pass and partitioning units) are widely accepted industrial application techniques used to reduce network complexity and flow rate targets in RCN. Cost equations relating to the piping and operating costs are added when interception units are designed in an RCN. Then, the problem is formulated as a two-stage optimization model whose objective functions are to minimize freshwater consumption and total annualized cost (TAC). The applicability of the developed model is demonstrated with two case studies. Single pass interception units with a fixed outlet concentration (CRout) reduced freshwater consumption by 23.16% and 46.3%, while partitioning units reduced consumption by 21.69% and 29% respectively, when compared to base systems.

Improved Ternary Diagram Approach for the Synthesis of a Resource Conservation Network with Multiple Properties. 2. Regeneration Reuse/Recycle

Environmental sustainability, rising cost of raw materials, and increasingly stringent emission legislation have motivated process industries to search for resource conservation alternatives. Process integration has been proven to be an effective technique for the synthesis of resource conservation network (RCN). In this first part of the series, the earlier developed clustering technique and ternary diagram by El-Halwagi et al. (AIChE J. 2004, 50 (8), 1854–1869) are extended for the synthesis of RCN with multiple properties. An analytic hierarchy process (AHP) is newly introduced to determine the quality ranking of the sources and sinks, which provides the basic information for the synthesis of RCN. In addition, the mean normalization approach (MNA) is proposed to normalize the property operators to avoid the possibility of the dimensionless property operators being in large magnitude difference when the property operators are divided by randomly selected reference values. Besides, the available region (...

Synthesis of Resource Conservation Networks in an Integrated Pulp and Paper Biorefinery

Pulp and paper production consumes a large amount of water and steam. In particular, water is used in brown stock washing system (BSWS) to separate spent white liquor from the pulp stream. The wastewater stream generated from BSWS, known as black liquor, is a potential biomass. In the current practice, black liquor is concentrated and burned in a recovery boiler to produce steam and electricity. However, recent development in an integrated biorefinery offers increased marketability in pulp and paper mills through the generation of both bioproducts and bioenergy. It is common practice for steam generated from the combustion of black liquor to be integrated with pulp and paper mill to satisfy its heating demands. Note that the water consumption in BSWS directly affects the quantity and quality of black liquor. This will later affect the potential for steam generation and integration in pulp and paper mill. Thus, in this work, water and heat integration is performed for a pulp and paper mill with biorefinery. An integrated pulp and paper biorefinery (IPPB) is proposed which accounts for different conversion pathways of pulp and paper mill biomass. Apart from combustion, several gasification pathways are considered. A nonlinear program (NLP) is formulated to synthesize an optimum IPPB with maximum resources conservation. Sensitivity analysis is then carried out based on the most significant parameters to analyze the robustness of the proposed IPPB.

Synthesis of resource conservation network with sink–source interaction

This article presents a mathematical model for the synthesis of resource conservation networks with interception placement. A comprehensive superstructure that incorporates all possible network configurations is used to facilitate the formulation. The synthesis task involves the allocation and interception of process sources to satisfy process sinks and environmental constraints. In particular, the interaction between the sinks and sources is addressed as the subject of the present study. Two literature case studies are solved to illustrate the proposed approach.