Use Of Residual Heat Research Articles

Industrial waste heat estimation for the manufacturing industry in Chile

Chile is one of the countries with most growing industries worldwide due to their mining and manufacturing industries. Nevertheless, at the same time there is a lack on energy generation and processes efficiency. The objectives of this paper are to estimate the amount of available industrial waste heat derived from the manufacturing industry in Chile, to locate these heat sources geographically, to assess the best technologies to be used to take advantage of this heat, and finally, to estimate the environmental savings of its reuse. Results showed that the sectors with the highest potential for the use of residual heat are food and beverages with an average accumulated potential of 62.9 PJ, basic metals with 21.5 PJ, chemical products with 15.1 PJ, paper products with 10.8 PJ, and non-metallic minerals with 10.6 PJ. With these data, the energy generation in Chile could be more efficient as well as the industrial processes could save more energy, reducing costs and raw materials.

Flue gas carbonation curing of steel slag blocks: Effects of residual heat and water vapor

To make full use of residual heat (temperature) and water vapor (relative humidity, RH) retained in flue gas, the compound effects of temperature (60–140 °C) and RH (2–60 %) of 2-hour CO2 curing on the compressive strength and CO2 fixation of basic oxygen furnace slag (BOFS) blocks were systematically investigated. The results indicated that, in general, an increase of curing temperature increased the compressive strength of the blocks. The high early compressive strength gain (31.3 MPa) at 2-hour for carbonated BOFS blocks was directly related to the microstructure densification and pore refinement due to rich formation of calcite. It should be noted that the supply of sufficient water vapor (≥40 % RH) is particularly important at high temperature (e.g. ≥ 120 °C) to offset the water loss due to water evaporation. Furthermore, under an extremely dry environment (2 % RH), the continuous flow-through of CO2 gas at high temperature not only resulted in no carbonation reaction at the outer layer of the freshly pressed blocks, but may also deteriorate the integrity of the pore structure matrix.

Innovative Technology Strategies for the Sustainable Development of Self-Produced Energy in the Colombian Industry

This research studies the current state of the Colombian industrial sector, which is focused on self-generation processes. The study’s objective is to search for viable technological strategies that strengthen this particular sector’s competitiveness and sustainable development. The analysis shows that internal combustion engines represent 49% of the technologies used for self-generation. The main fuel used in the sector is natural gas, with a percentage of 56%. The lack of strategies for the use of residual heat and technological inefficiencies caused a loss of 36% in the energy used in the Colombian industrial sector. Thermoelectric generators are a feasible way to recover energy from exhaust gases in engines used for self-generation. Additionally, they allow a 4% reduction in fuel consumption and an improvement in the engine’s energy efficiency. The use of hydrogen as fuel allows a 30% reduction in polluting emissions, such as CO2, CO, HC, and particulate matter. Hydrogen production processes, such as water electrolysis, allow the participation of Colombia’s solar energy potential, leading to sustainable hydrogen production, efficiency (60–80%), and a lower economic cost. In general, the application of thermoelectric generators and the use of hydrogen gas allow the improvement of the Colombian industrial sector’s environmental, social, and economic aspects due to greater competitiveness and the reduction in emissions and operating costs.

CFD evaluation of the influence of the parts of a shell and tube heat exchanger on heat transfer

This article deals with numerical fluid flow and heat transfer simulations of a shell and tube heat exchanger in which cooling water is heated by hot exhaust fumes. This heat exchanger plays a major role in a cogeneration unit, since it is responsible for the effective use of residual heat. The objective of the simulations is to evaluate the effects of various design changes made to the heat exchanger and their influence on the temperature fields and thus on the overall performance and efficiency of the system. In our analysis we looked at the baffles which cause the cross-current flow of water outside the tubes and at the placement of the gas inlet, i.e., on the distribution of the mass flow rate of the exhaust fumes inside these tubes.

Thermal analysis & modelling of phase change material used in low temperature industrial wastewater applications

The use of residual heat can reduce the energy needs of manufacturing plants. Low temperature industrial wastewater (IRW) heat can be used in heating plants. IRW heat removal can be accomplished using a Thermal Energy Storage Device (TES), which uses Phase Transition Materials (PCM). Wastewater The analysis is carried out by CFDs in the ANSYS CFX software. The heat absorption capacity and the IRW temperature difference are determined using paraffin Nano-fluid and alumina. The modelling represents the alumina Nano-fluid has a higher thermal capacity than paraffin wax, which is very useful for pharmaceutical systems that use industrial waste water for heating in the workshop. Temperature curves for different timings for paraffin and alumina based Nano-fluids were constructed using ANSYS CFX and temperature profiles were evaluated. Heat absorption in PCM is reduced when the material comes out of the industrial discharge pipe. Industrial wastewater loses maximum heat in the aluminium oxide water Nano-fluid, which is obtained in the form of a drop in temperature from 343 K to 324 K.

A high efficiency solar steam generation system with using residual heat to enhance steam escape

Solar steam generation has become the most promising solar-thermal applications in recent years. Scientists often focus on the search for superior materials, efficient structures, while ignoring the use of residual heat from the water at the bottom. In this paper, a membrane distillation system that utilizes residual heat was added in a new solar house of a domestic hot water and drinking water supply system in the first place. The pDA-rGO-PTFE membrane as an excellent evaporator was characterized in solar steam generation system, which possesses good hydrophilicity capacity and high intrinsic absorption properties. And at the optimal concentration of 20mg/mL, the evaporation rate and efficiency of pDA-rGO-PTFE membrane could reach up 1.45kg·m−2·h−1 and 93.8% respectively in one sun (one sun=1kw·m−2). The PTFE membrane as a separator was applied in a membrane distillation system. Under average 0.66 sun in the natural environment, the average evaporation rate of a new solar house could reach about 1.10kg·m−2·h−1, and there is an additional 0.71kg·m−2·h−1 membrane permeation flux by the residual heat. In addition, the new solar house showed an excellent durability and desalination ability, the ions rejection rations of the collected condensate water were close to 99.8%. Hence, we conclude that further ideas of a new solar house were provided for solving water scarcity, domestic water consumption and the application of solar steam generation in the future.

Influencing Intermetallic Layers of Hot Stamped Steel for Adhesively Bonded Plastic Metal Hybrids

Hot stamping of high strength steel parts is an established way to realize today ́s structural lightweight components in car bodies through sheet thickness reduction. The steel typically used for hot stamping is a boron-manganese 22MnB5 steel reaching up to 1,900 MPa in strength. New boron-manganese alloys achieving higher strength are expected to be developed, generating challenges for the manufacturing process by means of formability. Thus, a further reduction of steel thickness resulting in lighter components is not expected. Hybrid lightweight design approaches aim at weight reduction by reducing steel thickness and applying fiber-reinforced plastics (FRP) to regain structural stiffness and strength. The use of residual heat remaining from the hot stamping process allows to activate adhesives to bond FRP to hot stamped steel. The performances of adhesive bonds depend strongly on surface characteristics. To avoid scaling and decarburization during the heating process several coatings for hot stamped steels are used forming intermetallic layers through heat treatment. The most common coating in today’s automotive application is an Al-Si coating. Thus, the overall performance of the adhesive bonded hot stamped metal polymer hybrid is not only depending on adhesives performance but also strongly on the hot stamped steel’s coating performance. In this paper, the characteristics of hot stamped steel 22MnB5 Al-Si coating are investigated with regard to adhesion performance. Therefore, hot stamped specimens are manufactured under realistic industrial conditions investigating the influence of furnace temperature and dwell time on the overall coating and intermetallic layers of Al-Si coating. The specimens are investigated with respect to Al-Si coating thickness, lap shear strength of hybrid specimen and tensile strength of hot stamped steel demonstrating the dependency of the overall hybrid specimen performance from the coating performance.

Decreasing the Thermal Load on the Environment with the Help of Thermal Pumps in the Sewage Treatment System

We propose designs for practical use of residual heat of sewage by means of thermal-pump transformation of thermal energy in plants operating on inverse Rankine and Lorentz cycles, as well as a method for sewage heat removal in drainage canals of water removal systems based on the application of double-pipe heat exchangers known as Field tubes.

Closing the gap between lab and field cookstove tests: Benefits of multi-pot and sequencing cooking tasks through controlled burning cycles

There is a critical need for developing wood-burning cookstoves lab tests that better reflect their field performance, and that can be used to complement existing standard tests. This is particularly true for Plancha-type cookstove stoves, widely disseminated in Latin America, where existing tests, like Water Boiling Test (WBT) and Controlled Cooking Test (CCT), are either not well suited to these stoves or do not capture the simultaneous and sequential arrangement of local cooking practices –i.e., multi-pot cooking, pre-heating of meals, and use of residual heat. In this paper, we developed a “controlled cooking cycle” or “controlled burning cycle” (CBC) test to study the benefits, in terms of fuelwood and pollutants emissions savings, of multi-pot cooking arising from the integration of cooking tasks. Tests were conducted on the Patsari stove, a plancha-type stove that has been widely disseminated in Mexico and in other regions of Central America. We first used CCTs to evaluate the comparative energy and emissions performance of the Patsari stove relative to a traditional U-shaped open fire (U-type) for the most common cooking practices carried out in the Purepecha Region of Michoacan. We also compared results from the CBC multi-pot cooking with results from simply conducting the cooking tasks in series. All the CCTs and CBCs were carried out in a simulated kitchen at GIRA facilities in Patzcuaro, Michoacan, Mexico with two local cooks who performed all the cooking tasks in the traditional/typical manner of the region. Results from CCTs showed Patsari benefits relative to the open fires, in terms of fuelwood consumption and CO and PM2.5 emissions savings, vary among cooking tasks and range from negligible to 63% depending on the parameter and the task. The sequential cooking and integration of these tasks in a CBC result in average savings of 65% for CO, 65% for PM2.5 and 35% for fuelwood relative to the U-type, and of between 30% and 44% savings with respect to simply conducting the cooking tasks in series in the same stove. The CBC fuelwood savings obtained here are comparable with field results from Kitchen Performance Tests (KPT) conducted regionally by other authors. The results confirm that multi-pot cooking and a smart sequential integration of tasks developed by local users are key to achieve the maximum benefits from plancha-type stoves, and need to be much better reflected in standard lab tests.

Development of Solid Gas Generating Compositions to Ensure Non Explosiveness of Spent Orbital Stages of Liquid Rocket of Space Launch Vehicles

The choice is discussed of solid gas generating compositions for venting by hot combustion products a fuel tank of the spent orbital stage of a space launch vehicle with a main liquid rocket engine. Non explosiveness is achieved via eliminating the<br />possibility of freezing the drainage system when products of gasification (vapours of a propellant component + the remains of a gas boost + the hot products of combustion of solid gas generating compositions) are discharged from the tank into surrounding space. There are imposed requirements, constraints, and criteria for selecting solid gas generating compositions. When considering tank with the residues of liquid oxygen belonging to orbital spent stage of the launch vehicle «Zenith» the ways are shown how to ensure explosion safety, which on the basis of proposed approaches by selecting solid gas generating compositions (SGC) which generate oxygen and<br />nitrogen. As a criterion of choice of SGC the total mass of the gasification system is adopted, which includes the SGC mass for gasification of liquid propellant residues, the mass of the gas generator and the mass of system to supply the combustion products of SGC into the tank. It is proposed use of residual heat in the condensed phase of the SGC combustion products to heat up the drainage system, which will increase the probability of a trouble-free operation of the drainage system.

District Heating in the UK: Prospects for a Third National Programme

The UK has seen periodic attempts to develop large district heating (DH) networks to make use of residual heat from industry and power generation. Under concerns about climate change and energy security, DH has recently re-emerged in policy visions for future heat systems with small decentralised combined heat and power (CHP) generators playing a key role in the establishment of such networks. This paper draws on Stewart Russell’s accounts of earlier DH programmes, asking to what extent the reasons he concluded CHP and DH were systematically excluded continue to marginalise the technologies. In spite of governance changes which ostensibly open new opportunities for experimentation, key structural issues challenge the development of decentralised energy, particularly the alignment of the electricity sector to a centralised system and the dependency of local governments with limited capacity on central government. The reluctance of central government to engage in system planning and the failure to integrate policies related to energy production and energy consumption limit the eff ectiveness of support for DH.

An improved crude oil atmospheric distillation process for energy integration: Part II: New approach for energy saving by use of residual heat

In Part I of this paper, it was shown on thermodynamic grounds that introducing a flash in the preheating train of an atmospheric oil distillation process, together with an appropriate introduction of the resulting vapour into the column, could potentially bring substantial energy savings, by reducing the duty of the preheating furnace, by doing some pre-fractionation and by reducing the column irreversibilities. Part II expands on this idea by showing how this can be done while keeping the throughput and the product characteristics unchanged. The outcome is that placing several flashes after the heat exchangers and feeding the corresponding vapour streams to the appropriate trays of the column reduces the pumparound flows and the heat brought to the preheating train. The resulting heat deficit may then be compensated in an additional heat exchanger by using low level heat recuperated from the products of the distillation and/or imported from other processes. The use of this residual heat reduces the furnace duty by approximately an equivalent amount. Thus high level energy (fuel-gas burnt in the furnace) is replaced by residual low level heat. The simulation with an example flowsheet shows that the savings on fuel could be as high as 21%.