scholarly journals A Framework for Flexible and Cost-Efficient Retrofit Measures of Heat Exchanger Networks

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1472 ◽  
Author(s):  
Christian Langner ◽  
Elin Svensson ◽  
Simon Harvey
Keyword(s):  
Heat Exchanger ◽  
Heat Recovery ◽  
Main Idea ◽  
Efficient Design ◽  
Industrial Plants ◽  
Feasibility Assessment ◽  
Point Analysis ◽  
Heat Exchanger Networks ◽  
Cost Efficient ◽  
Design Proposal

Retrofitting of industrial heat recovery systems can contribute significantly to meeting energy efficiency targets for industrial plants. One issue to consider when screening retrofit design proposals is that industrial heat recovery systems must be able to handle variations, e.g., in inlet temperatures or heat capacity flow rates, in such a way that operational targets are reached. Consequently, there is a need for systematic retrofitting methodologies that are applicable to multi-period heat exchanger networks (HENs). In this study, a framework was developed to achieve flexible and cost-efficient retrofit measures of (industrial) HENs. The main idea is to split the retrofitting processes into several sub-steps. This splitting allows well-proven (single period) retrofit methodologies to be used to generate different design proposals, which are collected in a superstructure. By means of structural feasibility assessment, structurally infeasible design proposals can be discarded from further analysis, yielding a reduced superstructure. Additionally, critical point analysis is applied to identify those operating points within the uncertainty span that determine necessary overdesign of heat exchangers. In the final step, the most cost-efficient design proposal within the reduced superstructure is identified. The proposed framework was applied to a HEN retrofit case study to illustrate the proposed framework.

scholarly journals A New Graphical Technique for Energy Efficient Design of Heat Recovery System in Chemical/Refining Industries

2016 ◽  
Vol 4 (4) ◽  
pp. 33
Author(s):  
Dina Ahmed Kamel ◽  
Mamdouh Ayad Gadalla ◽  
Fatma Hanafy Ashour
Keyword(s):  
Heat Exchanger ◽  
Driving Forces ◽  
Process Integration ◽  
Minimum Energy ◽  
Pinch Analysis ◽  
Efficient Design ◽  
Heating And Cooling ◽  
Heat Exchanger Networks ◽  
Graphical Technique ◽  
Key Steps

Chemical processes are energy intensive industries; the majority of energy consumed in industrial processes is mainly used for heating and cooling requirements. This results in increasing the interest in obtaining the optimum design of the heat exchanger networks to reduce the energy consumption and face the growing energy crises. Most of the published literature over the last fifty years promotes the process integration technology as a main part of the process system engineering science. Graphical Pinch Analysis method normally includes two key steps, firstly obtaining the energy targets which include the minimum energy required for the HEN design, then designing the heat exchanger network (HEN). This paper introduces a new graphical approach for the design of new heat exchanger networks (HENs) based on pinch analysis rules. The HEN is represented on a simple graph, where the cold stream temperatures are plotted on the X-axis while the driving forces for each exchanger are plotted on the Y-axis. This graphical technique can describe the energy analysis problems in term of temperature driving force inside the heat exchanger, which is an important factor in the design process as the differences in these driving forces are involved in calculating the area of heat exchangers, and consequently affecting the cost.

scholarly journals Air purification in industrial plants producing automotive rubber components in terms of energy efficiency

2017 ◽  
Vol 7 (1) ◽  
pp. 106-114 ◽  
Author(s):  
Andrzej Grzebielec ◽  
Artur Rusowicz ◽  
Adam Szelągowski
Keyword(s):  
Energy Efficiency ◽  
Heat Exchanger ◽  
Economic Analysis ◽  
Power Consumption ◽  
Air Temperature ◽  
Heat Recovery ◽  
Waste Heat ◽  
Hot Water ◽  
Air Purification ◽  
Cost Efficient

AbstractIn automotive industry plants, which use injection molding machines for rubber processing, tar contaminates air to such an extent that air fails to enter standard heat recovery systems. Accumulated tar clogs ventilation heat recovery exchangers in just a few days. In the plant in which the research was conducted, tar contamination causes blockage of ventilation ducts. The effect of this phenomenon was that every half year channels had to be replaced with new ones, since the economic analysis has shown that cleaning them is not cost-efficient. Air temperature inside such plants is often, even in winter, higher than 30°C. The air, without any means of heat recovery, is discharged outside the buildings. The analyzed plant uses three types of media for production: hot water, cold water at 14°C (produced in a water chiller), and compressed air, generated in a unit with a rated power consumption of 180 kW. The aim of the study is to determine the energy efficiency improvement of this type of manufacturing plant. The main problem to solve is to provide an air purification process so that air can be used in heat recovery devices. The next problem to solve is to recover heat at such a temperature level that it would be possible to produce cold for technological purposes without air purification. Experimental studies have shown that air purification is feasible. By using one microjet head, a total of 75% of tar particles was removed from the air; by using 4 heads, a purification efficiency of 93% was obtained. This method of air purification causes air temperature to decrease from 35°C to 20°C, which significantly reduces the potential for heat recovery. The next step of the research was designing a cassette-plate heat exchanger to exchange heat without air purification. The economic analysis of such a solution revealed that replacing the heat exchanger with a new one even once a year was not cost-efficient. Another issue examined in the context of energy efficiency was the use of waste heat from the air compressor. Before any changes, the heat was picked up by a chilled water system. The idea was to use the heat for cold generation. Temperature of oil and air in the compressor exceeds 65°C, which makes it a perfect heat source for an adsorption refrigeration device. This solution reduced the cooling demand by 147 kW, thus reducing power consumption by 36.75 kW. This study shows that even in factories where air is heavily polluted with tar, there are huge potentials for energy recovery using existing technical solutions. It is important to note that problems of this kind should always be approached individually.

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