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The purpose of this paper is to recover the waste heat of flue gas heat exchanger (FGHE) as efficiently as possible and avoid the acid dew corrosion of that.

A novel flue gas waste heat recovery system was proposed in the paper. The dynamic mathematical models of key equipment in that were established based on theory and experiment method. The proportion integration differentiation-differentiation (PID-P) cascade control method based on particle swarm optimization algorithm was used to control the outlet temperature of FGHE. The dynamic characteristics of the flue gas heat exchange system were simulated by the particle swarm optimization algorithm with different fitness functions.

The PID-P temperature controller parameters can be quickly and effectively obtained by the particle swarm optimization algorithm based on the fitness function of integral time absolute error (ITAE). The overshoot, rise time and adjusting time of the novel system are 2, 83 and 105s, respectively. Compared with the traditional two-step tuning (T-ST) method, the novel system is better in dynamic and steady-state performance. The overshoot and the adjustment time of the system are reduced by 44% and 328s, respectively. ITAE is a performance evaluation index for control system with good engineering practicability and selectivity.

The dynamic mathematical model of key equipment in the new flue gas waste heat recovery system is established and the system's control strategies and methods are explored.

The unique chimney design for Drax power station resulted in problems with conventional linings. Low exit flue gas temperatures made it necessary for the chimney flues to be protected from deposited acid attack. A cheap plastic material was initially used to protect the flues, but it failed during precommissioning tests. An alternative protection had to be found in the short period before the chimney became operational. N.E. Region Scientific Services Department together with a manufacturer have developed a new fluoroelastomer plastic lining. The new lining has been installed in two of the flues in the Drax chimney and its performance is being monitored. Life expectancy predictions have been made, based on theoretical treatments of experimental data.

The purpose of this paper is to develop a 3-D fully transient numerical model of the heat and fluid flow associated with the chemical reactions that occur in the heating system of the coke oven battery. As a result, the model can be used to provide data for the control system of the battery to reduce energy consumption and emissions and to obtain a product of the desired quality.

In the proposed model, an accurate representation of the heating flue geometry, the volumetric heat sources as a result of the coke oven gas combustion, the temperature- and mole fraction-dependent properties of the gases were taken into account. The most important part of the model was the unsteady boundary condition definition that allowed the modeling of the periodic heat delivery to the two oven heating walls, both in the coking and the reversion cycles.

The temperatures obtained using the computational fluid dynamics (CFD) model showed the same pattern of temperature variations as that observed in the experiments. It was also found that the quality of the temperature variation predictions was highly dependent on the radiation model settings.

The CFD models available in the literature describe the steady or pseudo-steady state operation of the heating system of the coke oven battery. The model developed in this work fully reflects the unsteady character of this heating system. Moreover, the proposed model is prepared for coupling with a model of the coking process that occurs in the two neighboring coke oven chambers.

In fire resistance tests (FRTs) of building materials, a crucial criterion to pass the test procedure is to avoid the leakage of the hot flue gases caused by gaps and cracks occurring due to the thermal exposure. The present study's aim is to calculate the deformation of a steel door, which is embedded within a wall made of bricks, and qualitatively determine the flue gas leakage.

A computational fluid dynamics/finite element method (CFD/FEM) coupling was introduced representing an intermediate approach between a one-way and a full two-way coupling methodology, leading to a simplified two-way coupling (STWC). In contrast to a full two way-coupling, the heat transfer through the steel door was simulated based on a one-way approach. Subsequently, the predicted temperatures at the door from the one-way simulation were used in the following CFD/FEM simulation, where the fluid flow inside and outside the furnace as well as the deformation of the door were calculated simultaneously.

The simulation showed large gaps and flue gas leakage above the door lock and at the upper edge of the door, which was in close accordance to the experiment. Furthermore, it was found that STWC predicted similar deformations compared to the one-way coupling.

Since two-way coupling approaches for fluid/structure interaction in fire research are computationally demanding, the number of studies is low. Only a few are dealing with the flue gas exit from rooms due to destruction of solid components. Thus, the present study is the first two-way approach dealing with flue gas leakage due to gap formation.

Smoke and dust emissions from industrial furnaces can do great harm to the environment and human health. This paper aims to analyze the morphology, diameter and elements of the submicron particles from the furnace flues and the nearby ambient air by using two typical industrial furnaces, the sintering furnace and the electric furnace.

Two typical industrial furnaces, the sintering furnace and the electric furnace, were chosen in this study, to analyze the morphology, diameter and elements of the submicron particles from the furnace flues and the near-by ambient air.

The results show that the particles from the two furnaces are mainly in the small sizes of 0.3-0.6 μm. Particles from sintering plant flue are mainly spherical and rich in K and Cl, whereas those from the electric plant flue are mainly particles rich in metal elements, such as Zn and Fe, and have different morphology.

The particles in the atmosphere nearby the two furnaces contain aged particles from the flue, lots of spherical particles, rectangle particles and various aggregations. The elements of those particles are complex.

Ammonia injection grid (AIG) is used as an input device for ammonia which reacts with NO_x in the selective catalytic reduction (SCR) reactor. However, non-uniform concentration distribution of ammonia could produce partially poisoning or deposits of the catalyst. In this work, for making ammonia widely distributed throughout the flue gas and fully mixed, an optimization method of AIG is proposed.

Depending on the complexity of fluid flow, the relation between the concentration distributions of ammonia and the geometric parameters of AIG is nonlinear. Based on a certain amount of AIG samples, the computational fluid dynamics (CFD) simulations are applied to propose the agent model which describes the functional relation of the deviation of ammonia concentration and the geometric parameters of AIG. The optimization model of AIG based on the agent model is established. The optimized AIG based on the agent model can be used to produce uniform concentration distributions of ammonia, especially in the case that velocity distribution of flue gas is non-uniform.

For qualitatively confirming this optimization method, the three-dimensional CFD simulation of the optimized AIG is carried out. The results reveal that the diffusion process of ammonia gas is consistent with the development of the local vortices, which have a certain relation with the velocity distribution of the flue gas. The unequal ammonia injection designed by the optimization based on the agent model promotes a better mixing of ammonia and flue gas.

In this work, first, the method for optimizing AIG based on the agent model is proposed. Second, the three-dimensional CFD modeling and simulation of the optimized AIG is carried out, and the mixing effects of ammonia and flue gas are presented.

Last month the mechanism of flue‐gas corrosion and methods of assessing it were discussed. Continuing this review the author describes some industrial studies of corrosion by sulphur oxides in industrial appliances; sulphuric acid corrosion in domestic appliances and chimneys, flue‐gas corrosion by chlorine compounds and oxides of nitrogen.

In a new build waste incinerator, the waste (refuse derived fuel) was burned on a discontinuous moving grate. Frequent furnace overpressure peaks occurred because of this firing method and as a result, flue gas and fly‐ash were pushed out of the boiler and into the building. During the plant start up period, a seal in a water‐feed pipeline broke, and a large amount of condensed steam was discharged into the boiler house. Shortly thereafter, very severe corrosion was noticed on the galvanised gangways, steel building components, the boiler aluminium sheeting and on processing lines. A theoretical study of the condensation of the flue gas indicated that sulphuric acid would condense before it reached the external aluminium sheeting and that under normal conditions, dry hydrochloric acid fumes would be removed by the boiler house ventilators. However, the steam leakage had caused the hydrochloric acid to be dissolved in the condensed water and that had resulted in the severe corrosion damage, which had become evident subsequently.

Industrial chimneys are a great part of environmental protection in industrial countries. In recent years many of them have been used to carrying away very aggressive gases from boilers and flue gas desulphurisation (FGD) units below acid dew‐point temperature. It is opf very important to modernize the old stacks and protect them against corrosion. The proper anti‐corrosion protection of modern high stacks is also an important technical and economical problem. In this paper the mechanism of acid dew‐point corrosion, as well as construction of industrial chimneys, methods of their anti‐corrosion protection and modernisation are described.

In the first part of the paper, which outlines the laboratory and field investigations on corrosion by flue gases from solid fuel combustion carried out by the British Coal Utilisation Research Association, the effects of different flue gas constituents on corrosion phenomena are discussed. Laboratory studies of the effects of fuel type and method of combustion on the sulphuric acid content of combustion gases are described. The second part presents the results of measurements of the condensation characteristics of flue gases from water‐tube boilers in power stations and from various industrial boilers and furnaces; investigations into the use of additives are described briefly. The final section is concerned with some theoretical considerations of effects of fuel type, burning rate, etc., on the amounts of sulphuric acid likely to be present in the combustion products from domestic appliances.