Zainuddin Abd. Manan

A new algebraic pinch analysis tool for optimising CO2 capture, utilisation and storage

Optimal CO2reduction planning can curb the rise in environmental emissions due to the increase in energy demand and utilisation. Carbon (more precisely, CO2) Capture and Storage (CCS) has been one of the proposed solutions to control CO2emissions. However, mitigating CO2emissions via CO2storage in geological reservoirs without utilisation is neither a sustainable solution, nor really a clean technology option. This paper introduces a new algebraic method for targeting the optimum CO2capture, utilisation and storage based on the Pinch Analysis approach. A new Total Site CO2Integration concept is introduced. The concept is to capture CO2with certain quality from various plants on the Total Site and inject it into CO2headers. The CO2headers are divided into certain composition ranges. The CO2headers can satisfy the CO2demands for various industries located along the headers, which require CO2as its raw material. The CO2can be further regenerated, and mixed as needed with pure CO2generated from one or multiple centralised CO2plant if required. The excess CO2is to be sent to geological storage. The proper utilisation of CO2will reduce the amount of CO2needed to be stored. This will extend the geological carbon storage-life capacity. Aside from estimating CO2utilisation, this method also allows an industrial site planner to identify the suitable industries that can act as CO2sources or CO2demands for a given region.

Regional and total site CO2 integration considering purification and pressure drop

The application of Pinch Analysis (PA) targeting method has been recently explored to the design of CO2 emission reduction in Total Site planning of CO2 capture, utilisation and storage. The algebraic method based on Problem Table Algorithm (PTA) for Total Site CO2 Integration (TSCI) provides the designer with integrated CO2 capture, utilisation and storage (CCUS) for the optimal CO2 emission reduction. In TSCI, CO2 is captured with certain quality from various plants and supply into system header pipeline. The CO2 header could satisfy various CO2 demands for various industry located in the header, and only surplus CO2 is to be sent to storage. The extended methodology with consideration of purification and pressure drop in TSCI planning is proposed. The CO2 supply from the header could satisfy the purity demand through a process of purification. Purification is a process to upgrade the purity level have not been considered in the previously used in TSCI method. In addition, pressure drop during CO2 transportation in the pipeline system has been included to identify the implication of pressure drop in TSCI design and has resulted about 29.01 MPa of the total pressure drop (∆Pd). Therefore, 68.2 t/h of flow rate (FT) of 81 % purity level header is supplied and purified to satisfy the 50 t/h of demand, at 99 % purity level. The improved methodology of TSCI network has been further developed and provides a more realistic scenario for CCUS implementation.

A simple case study on application in synthesising a feasible heat exchanger network

kamaruddin@cheme.utm.my Heat exchanger network (HEN) is very important to optimise energy usage in process industry. Heat exchanger network synthesis is an important process synthesis problem where different tools and methods have been presented to solve this synthesis problem. In HEN synthesis, the feasibility of the HEN design is not taken into consideration. The HEN design may not be able to be implemented in industrial applications. It is essential to check the feasibility of a design before it is being implemented in the industry. The objective of this paper is to present the application of a new flexible and operable heat exchanger network (FNO HEN) methodology in synthesising a feasible HEN using a simple case study. The novelty of this work is to determine an optimal ΔTmin value that gives minimum external energy requirement (EER) and heat exchanger area (HEA) as well as simultaneously analyse the feasibility of the HEN design in an easy, systematic and efficient manner. Using the new developed FNO HEN methodology framework, HEN design target, which is the value of ΔTmin is determined to obtain the feasible HEN design. From process design point of view, ΔTmin value determines the size of heat exchanger in the network as well as energy saving. A process simulator is used to check the process feasibility of the HEN designs. With the use of the feasible HEN trade-off plot, which is a plot of EER and HEA at different value of ΔTmin with additional of feasibility area, the optimal feasible HEN design which satisfies external energy requirement (operability), heat exchanger area (capital) and process feasibility has been successfully determined.

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.

A new graphical method for heat exchanger network design involving phase changes

Heat Exchanger Network Synthesis (HENS) plays a major role for effective energy integration in chemical process plants. In HENS, several hot and cold streams and utilities with specific inlet and desired outlet temperatures are involved. Stream Temperature versus Enthalpy Plot (STEP) is new graphical tool which can complement Composite Curves (CCs) and Grid Diagram (GD) by representing individual, as opposed to composite streams on temperature versus enthalpy diagram, and by allowing designers to perform targeting and network design simultaneously. Previous researches do not consider the effect of phase changes in the hot and cold streams and assume constant specific heat capacity, Cp along process streams. The aim of this study is to propose a new graphical method for HENS targeting and network design involving phase changes. Using an illustrative example, STEP procedure is proposed for the determination of minimum utility targets with the minimum number of heat exchangers. Results of the analysis using the modified STEP is compared with those obtained using Composite Curves. It is found that the modified STEP provides more accurate and realistic results and allows the selection of different types of heat exchangers.

Popa-sharps: a New Framework for Cost-effective Design of Hybrid Power Systems

Development of Power Pinch Analysis (PoPA) for the design and optimisation of Hybrid Power Systems (HPS) is steadily progressing. Even though PoPA has been developed for widespread applications in HPS design analysis, the economic aspect still needs more attention. This work presents a new framework for the design of a cost-effective HPS by incorporating PoPA with a cost-screening tool known as the Systematic Hierarchical Approach for Resilient Process Screening (SHARPS). SHARPS which was originally developed to screen various process changes options in water network is adapted to imbed cost analysis and renewable energy (RE) technology screening in power network. Demonstration on an illustrative case study shows that the proposed framework can provide the best HPS scheme considering the system efficiency, while satisfying the desired payback period.

Sustainability assessment of a municipal sewage treatment plant using a single green performance indicator

A Municipal Sewage Treatment Plant (MSTP) involves multiple processes for treating wastewater. In a MSTP, there are resources consumed, emissions as well as effluent discharged that could potentially cause environmental problems. There has bezen much research about environmental impact of a MSTP such as the MSTP carbon footprint, MSTP energy consumption and MSTP emission discharge. Although these studies have contributed towards reduction of environmental impact of a MSTP, so far, there has not been any study done to quantify the overall green performance of an MSTP. This paper extends the Green Index (GI) tool for the assessment of an MSTP environment. This study is focused on investigating the green performance of two types of MSTP, namely the Ludzack-Ettinger process and Bardenpho process. The conventional process is used as the benchmark for the purpose of comparison. The GI development for a MSTP involves two stages. The first stage involves formulation of a weighting scheme by applying factor analysis on the green elements data of the MSTP. This is followed by formulation of the GI using stock market composite index. The GI allows the use of a single index to be used to quantitatively assess the overall green performance, and the actual measure of the overall greenness of the MSTP facility. A single quantitative index to substitute multiple green elements would help organisations to objectively compare and select the type of MSTP process that is greener, promotes cleaner production, and has less adverse impact towards the environment. GI could help organisations to quantitatively and effectively monitor and analyse the actual green performance of a process in a retrofit or a conservation program. Result shows that GI would help organisation to choose which process would have less environmental impact. The GI graph accommodates facility manager with a figurative tool to visualise on the performance of MSTP either for retrofit or conservation programmed.

An Evaluation of Thermodynamic Models for the Prediction of Solubility of Phytochemicals from Orthosiphon Staminues in Ethanol

Orthosiphon Staminues (OS) is a species of herbs locally known in Malaysia as Misai Kucing. This study aims to analyse the performance of existing group contribution models in predicting the solubilities of phytochemical compounds from OS in ethanol. The compounds are oleanolic acid, ursolic acid and betulinic acid which have properties of pharmaceutical importance. The solubility experimental data of the compounds in ethanol were derived from the literature and were compared with the predictions made by the original UNIFAC, Modified UNIFAC (Dortmund), and Pharma Modified UNIFAC. The very high ranges of ARD values of between 40.86% to 98.6% calculated in this work shows that the models presented in this paper are not able to accurately predict the solubility of the studied phytochemical compounds in ethanol.

Initial analysis on heat exchanger networks of fatty acid fractionation plant to optimize energy recovery and controllability

The objective of this paper is to present the initial analysis on the energy recovery and controllability of the existing heat integrated fatty acid fractionation plant. From this initial analysis, the existing heat integrated fatty acid fractionation plant is analysed to know the either the existing heat exchanger networks (HENs) satisfied the design criteria, or controllability criteria by using trade-off plot. According to the trade-off plot, if the existing HENs is better in terms of design criteria, then more efforts need to be invested to control the network. On the other hand, if the existing HENs is better in terms of controllability criteria, then more efforts need to be invested to reduce the energy consumption. In this study, the initial analysis means the value of the ?Tmin used for the current HENs is investigated and the controllability of the network is predicted by using trade-off plot. In order to investigate the value of the ?Tmin used for the current HENs, only the first two stages of the model-based flexible and operable HENs is used. In the Stage 1, the value of the ?Tmin is investigated by selecting the value of the ?Tmin ranging from 10 °C to 40 °C with the increment of 10 °C. Then, HEN is synthesized for the selected value of the ?Tmin. Once the networks have been synthesized, all candidates are transferred into a process simulator to test their process feasibility in Stage 2 where the unfeasible candidates will be eliminated. Then all feasible candidates will be predicted in terms of their controllability performance by using trade-off plot. Energy integrated fatty acid fractionation plant is used as a case study for this initial analysis. This paper only considers steady state controllability test without considering process dynamics.

A cost effective minimum water network model for intra and interplant system

This paper presents a mathematical model for a cost effective minimum water network for intra and interplant involving multiple contaminants for a set of process plants. A generic mixed integer non-linear programming (MINLP) model has been developed based on water network superstructure to targets and design minimum water network for retrofit design. The model includes all levels of the water management hierarchy (i.e. source elimination, source reduction, direct reuse/ outsourcing of external water, regeneration reuse and fresh water) and is set to achieve a payback period criteria set by the designer to ensure cost effectiveness of the solution. The approach is illustrated by using an inter-plant case study involving a semiconductor and a chlor-alkali plant. The results show that the new freshwater and wastewater targets are 14.99 t/hr and 2.94 t/hr respectively with capital cost of USD 276,900 and payback period of 3 years. This represents a 54.90% increment in freshwater reduction as compared to Handani et al [1] and Wan Alwi et al [2].