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It is critical to limit global warming to 1.5 °C by the year 2100 to minimize catastrophic impacts. The increased integration of renewable energy, alongside CO2capture and storage(CCS) deployment in energy planning, remains as a key mitigation technique in minimizing climate change impacts. Although renewable energy generation approaches the ideal of a carbon-neutral system, other processes such as fossil fuel-based generation, manufacturing, and transportation are net-carbon positive. Additionally, renewable energy poses challenges such as its sensitivity to environmental conditions, geographical location, and seasonal changes. On the other hand, CCS entails a high capital expenditure, as well as additional operating costs due to parasitic power loss. Therefore, the deployment of negative emission technologies(NETs) as a carbon management option is imperative. The generation of electricity from power plants with the installation of NETs can offset positive emissions from elsewhere in a system. This paper presents an extended graphical technique for the incorporation of NETs during energy planning. The graphical technique that was originally developed for the planning of CCS deployment in power plants is now extended to determine the minimum NET requirement during energy planning. Three examples are solved to illustrate the methodology of the extended graphical technique in determining the minimum NET requirement during energy planning.

In this paper, a recently established automated targeting model(ATM) for a heating utility system is extended to integrate the phase separation system in an oil and gas platform to determine its optimum overall cost. A heating medium is used at the oil and gas platform to reduce the viscosity of heavy crude oil from the well and to facilitate the separation process by reducing the size and cost of the separators. The downside of this approach is the additional cost associated with increased heating utility. Therefore, an optimization approach is needed to reconcile the various objectives and to minimize the overall cost. The proposed approach makes use of the pinch analysis-based ATM to find the optimum trade-off between the heating medium system and separation processes. For the ATM, a novel algorithm is introduced to automate the process for temperature sorting and also to locate the heating medium users in their associated temperature intervals. This enables the utility targeting step to be performed despite the changes in temperatures of the heating medium at the crude oil heaters; the latter are located upstream of the crude oil separators. The optimization problem is decomposed into two subproblems. First, the phase separators are sized for optimum cost based on different inlet temperatures. These optimum costs are then associated with the heating utility system by the choice of outlet temperatures at the heaters. Next, the model is solved for overall optimum cost. An industrial case study is used to elucidate the application of the newly proposed approach.

Carbon capture and storage (CCS) reduces carbon dioxide (CO2) emissions by sequestration of captured CO2for long-term storage whereas carbon capture and utilization (CCU) offers resource conservation benefits by displacing the need for extracted CO2from natural sources. The integration of these two results in a carbon capture, utilization, and storage (CCUS) system, which either uses CO2for profitable applications or stores it in the reservoirs. One of the key problems in CCS systems is to optimally match the sources (e.g., CO2captured from fossil-fueled power plants) and the sinks (e.g., available geological reservoirs for storing the captured CO2). In practice, the geological storage sites may be available at different times and have limitations on the maximum CO2storage capacity and the injectivity rate, subject to other geological characteristics. This work proposes an improved pinch analysis-based methodology by simultaneously considering the injectivity constraints and variable availability of all sources and sinks. Two types of CO2storage are considered in this work, that is, sinks with fixed life and sinks with fixed capacity. A new CCUS Mapping Diagramis presented to show the capture of CO2to the individual sinks. Four illustrative examples demonstrate the applicability of the proposed methodology to the CCUS systems in which purity is not a constraint in CO2utilization. In some cases, the improved methodology overcomes the pitfall of the previous method by identifying rigorous CCUS targets.

Optimal synthesis of a heat-integrated water network (HIWN) accounts for the simultaneous conservation of energy and water resources. A significant amount of research work, ranging from complex nonlinear formulations to simplified linear models, has been carried out for the synthesis of HIWNs. The incorporation of interception units leads to additional water and energy conservation but results in nonlinear formulations for heat-integrated water regeneration network (HIWRN) synthesis. This paper proposes a linear mathematical formulation, based on the transshipment model, for the optimization of HIWRNs using distributed interception units. As a result of a reduced number of variables and the absence of nonlinearities, the convergence efficiency is enhanced. The use of distributed interception units allows the regeneration streams to maintain their temperatures, thereby saving a significant amount of energy. A three-stage sequential approach and a simultaneous strategy are proposed for HIWRN synthesis. Although the simultaneous solution strategy provides cost optimal results, the three-stage sequential strategy is preferred in areas dealing with water scarcity and intermittent supply. The solution strategy is applicable to single as well as multiple-contaminant problems for single pass interception units with a fixed outlet and fixed removal ratio (RR). The methodology is demonstrated through literature examples for both types of interception units.

An improved source shift algorithm (SSA) and water path analysis (WPA) is proposed in this work to evolve a preliminary water network. The earlier version of SSA, which reduces the complexity of a preliminary water network, is iterative in nature and involves trial-and-error solution. The improved SSA proposed in this work is noniterative and is able to evolve the preliminary water network while maintaining its minimum freshwater and wastewater flow rates. Moreover, the WPA is used to shift the water loads along a water path to reduce the number of interconnections by incurring a penalty on both freshwater and wastewater flow rates. Three literature examples are solved to illustrate the applicability of the developed methods.

This work describes the gas cascade analysis (GCA) as an extension to cascade analysis technique for targeting the minimum flowrates for water and property-based networks. The GCA technique enables quick and accurate identification of the minimum flowrate targets, pinch-point location(s), and resource allocation targets for a utility gas network. Multiple-pinch problems and appropriate selection of gas purification techniques were systematically assessed via the GCA. The GCA technique was successfully used to determine the minimum flowrate targets for nitrogen, oxygen, and hydrogen utility gas networks prior to detailed design.

Pd/alumina composite membranes were fabricated using the generally practiced electroless plating process involving two-step activation of a symmetric 0.2 μm α-alumina microfilter with tin (Sn) chloride sensitizer (containing SnCl2 and SnCl4) and palladium(II) chloride (PdCl2). Pd films were deposited on these activated supports with a hydrazine- (N2H4-) and PdCl2-containing electroless plating bath. When these membranes were tested at 823 K for several days, the ideal H2/N2 separation factor (pure gas permeability ratio) declined substantially, depending on the membrane thickness. Modifications to the activation procedure minimized the amount of Sn chloride used in the sensitizing step. This reduced the selectivity decline, although the problem was not eliminated. The amount of Sn present at the Pd/ceramic interface was qualitatively related to the high-temperature performance. Possible routes for pore formation and selectivity decline are suggested. Sn chloride was removed from the process entirely with a new activation technique utilizing palladium(II) acetate (Pd(O2CCH3)2). Prior to electroless plating, substrates were dip-coated in a chloroform solution of Pd acetate, dried, calcined, and then reduced in flowing H2. At 973 K, nitrogen flux through these membranes remained constant for a period of at least a week. However, hydrogen permeability decreased at 873 K and above because of annealing.