Technological Field:

The invention relates to a PH exchanger for WHR plants with ORC systems, which make production in heavy industry (especially cement) and emit high- temperature waste flue gas to nature.

State of the Art:

WHR facilities with ORC systems are used in facilities that make production in heavy industry (especially cement) and that emit high-temperature waste flue gas to nature. The aim of these facilities is to reduce the carbon emissions released to the nature and to decrease the consumption of renewable resources by converting high-temperature flue gas into electrical energy. These facilities have heat exchange elements such as AQC exchanger and PH exchanger. The invention in this specification is related to the PH exchanger.

Waste heat recovery (WHR) is a profitable, low-carbon and environmentally friendly technology for generating electricity by recovering heat from industrial processes. The most common technology used to generate energy from waste heat is generally based on the Rankine cycle. This thermodynamic cycle is performed by a working fluid and consists of a heat source (boiler) that generates a high-pressure vapor, which is subsequently expanded through a turbo generator producing power.

In general, there are two different types of working fluid used in the cycle:

• Water (most commonly used): Steam Rankine Cycle (SRC) technology

• Organic fluid: Organic Rankine Cycle (ORC) technology Systems installed in Turkey use SRC technology. The disadvantage of this system is that while producing renewable energy, it consumes another natural resource - water (2,000 m3/day). As the technologies of SRC and ORC systems are different, the heat exchangers (boilers) used in these systems are also different.

In the flow diagram, water is pumped to high pressure before entering the waste heat recovery boiler. The water is evaporated to high pressure steam by the hot exhaust from the process and then expanded to lower temperature and pressure in a turbine and generates mechanical power, driving an electrical generator.

Steam turbines used in the known art are one of the oldest and most versatile energy generation technologies used in cement factories. They have lower installation costs than other Rankine cycle systems on a cost basis. (US$/kW). A higher waste heat temperature is required to operate: optimum > 260°C (500°F). Lower temperature or pressure may cause erosion in the turbine. They require a full-time operator. They require feedwater conditioning systems, which can affect system performance, and water/air cooler condensers. In general, they fit well with large furnaces and systems with low feedstock water content.

As a result of the literature search, the Korean patent document KR20180076922A mentions a system based on ORC technology and used for energy saving on ships. Although the present invention relates to cement plants, it does not include the suspension system, cleaning system, monoblock structure and connection equipment in the Korean patented invention.

Brief Description of the Invention:

The invention is a PH exchanger, which exceeds the known state of the art, eliminates the disadvantages, and offers extra advantages. The invention has many advantages. The heat exchangers developed with the invention are designed in a monoblock structure. The heat exchangers in the existing structures consist of 36-42 modules while they will consist of 6-8 monoblock structures thanks to the invention under this specification. Consequently, the number of welds decreases, leading to reduced risk of damage and malfunction. Thanks to the decreased number of welds, malfunctions and errors resulting from welding are prevented and the associated assembly and maintenance costs are reduced.

The PH heat exchanger designed with the invention has a suspended system. In this way, the negativities arising from ground movements (earthquake and similar ground movements) will be reduced. In this system to be designed, the heat exchangers will be a suspended system (independent of the reinforced concrete structure to which they will be mounted). It is known that different oscillation frequencies occur on reinforced concrete and steel structures due to natural ground movements. As a result, the probability of damage is high in these two different structures, which are connected to each other. Thanks to the suspended system, the heat exchanger is independent and the adverse effects of structures on each other are reduced.

Two cleaning methods are used in the invention. The effectiveness of the cleaning process is increased by the hammering and the sound waves methods. A cleaning system has been developed against the possibility of dust sticking on the pipes used in the heat exchangers and thus preventing the heat flow. Due to the fact that the PH exchanger is free, the hammering method and the cleaning system with sound waves are effective in spilling the dust that will form in the heat exchanger.

The hammering method is defined as the method of hitting the heat exchanger from a determined point at certain intervals by a self-returning mechanical system with the help of compressed air. Sonic cleaning method, on the other hand, can be defined as the method of using the sound waves formed by feeding the compressed air to the heat exchanger with sudden shocks.

The particles deposited on the pipe surfaces have a potential energy. The kinetic energy that this potential energy will need to be detached by being caught in the gas flow inside is provided by the violence created inside.

The sonic cleaning method generally aims to create a sound wave that has an energy level above the force that forces particles suspended in gas streams or space to bond with each other and coat the surfaces. The sound force separates the particles from the surface they are attached to and breaks their bonds with each other, thus making the particles transportable by gas stream or gravity. During the external gas flow on the pipe surfaces, the fluid flowing over a stationary surface comes to a complete stop when it contacts the surface due to the no-slip condition. This non-uniform flue gas flow pattern is a laminar flow. The flow over the pipe bundles is a turbulent flow at a very low velocity. Since the gas velocity is stagnant on the boundary layer, the particles carried on the flue gas cause accumulation on the pipe surfaces.

In the hammering method, cleaning is performed with a pneumatic system developed for the removal of stuck and dead volume heaps. In general, the healthy and continuous operation of the shaking systems, which are designed as time-adjusted with the hammering method, is very important for heat exchanger efficiency. It can be described as the impact method applied to a determined point at certain intervals by a self-returning mechanical system with the help of compressed air.

Heat exchange surfaces have very different properties for different fuels. High temperature flue gas passing over heat packs and other surfaces in different parts of a boiler contains components of alkali chlorides, lead chlorides, zinc chlorides and sticky ash. At flue gas temperature, economizers, air preheaters, and catalysts are typically areas where stickiness is very low, but heaps are greater. SONIC systems have been observed to be successful in biomass fuels where the flue gas temperature is up to 800°C.

Explanation of Figures:

The invention will be described with reference to the accompanying figures so that the properties of the invention will be more clearly understood. However, it is not intended to limit the invention to these particular embodiments. On the contrary, it is also intended to cover all alternatives, modifications and equivalents that may be included within the scope of the invention as defined by the appended claims. It is to be understood that the details are shown for the sole purpose of illustrating preferred embodiments of the present invention and are presented to provide the most useful and easy-to-understand description of both the methods and the conventions and conceptual features of the invention. These figures are:

Figure 1 Sectional view of the PH heat exchanger, the subject of the invention.

Figure 2 View of the modules inside the PH heat exchanger, the subject of the invention.

Figure 3 Detail view of the suspension system of the PH heat exchanger, the subject of the invention.

Figure 4 Detail view of the cleaning pipe integrated into the PH heat exchanger, the subject of the invention.

Figures that will help to understand this invention are numbered as indicated in the attached picture and are given below with their names.

Explanation of References:

1. PH exchanger

10-Module 11. Suspension beam

12.Main suspension

13. Intermediate suspension

14.Dust funnel

15.Earthquake support

16.Cleaning pipe

17.Connecting pipe

A. Exhaust gas inlet

B. Exhaust gas outlet

Description of the Invention:

In this detailed description, the PH exchanger (1 ), which is the subject of the invention, is only illustrated with examples that will not create any limiting effect for a better understanding of the subject. The specification describes a PH exchanger (1 ) for WHR facilities with ORC systems, which make production in heavy industry (especially cement), and emit high-temperature waste flue gas to nature.

The PH exchanger (1 ) is the equipment installed to transfer heat from the exhaust gas from the cement kiln preheater (PH). Figure 1 represents the sectional view of the PH exchanger (1 ), the subject of the invention. Accordingly, perspective view of the PH exchanger is presented. The PH exchanger (1 ) consists of 6 or 8 modules laid one under the other. The exhaust gas from the exhaust gas inlet (A) transfers its heat by circulating in the modules (10) and leaves the system from the exhaust gas outlet (B). The exhaust gas circulating in the modules (10) passes from one module (10) to the other with the help of connecting pipes (17). Meanwhile, dust and similar residues accumulated in the modules (10) are cleaned with cleaning systems and accumulated in the dust funnel (14) in order to avoid a decrease in the performance. A suspended system is used in the PH exchanger (1 ), the subject of the invention. This can be seen in figure 2 and in more detail in figure 3. The modules (10) are suspended from the upper part to a suspension beam (11 ) with main suspensions (12). There are intermediate suspensions (13) between the modules (10).

In this way, the connection of the PH heat exchanger (1) with the ground is cut off, preventing the adverse effects of earthquakes and similar ground movements on the structure. In addition, the PH exchanger (1 ) is attached to a structure called earthquake support (15) under the modules (10). As it can be understood from this, the static structure of the PH exchanger (1 ) is provided by the suspension beam (11 ), the main suspension (12), the intermediate suspensions (13) and the earthquake support (15) at the bottom.

In the invention, dust and similar residues accumulated in the modules of the PH exchanger (1 ) must be cleaned. Two cleaning methods are used in the invention. One of them is sonic cleaning. A cleaning tube (16) is placed next to each module (10) for sonic cleaning. Sound waves are sent from the cleaning pipes (16) to the modules (10) of the PH exchanger (1). The sound force separates the dust particles from the surface they are attached to and breaks their bonds with each other, thus making the particles transportable by gas stream or gravity.

The hammering method is another method used for cleaning. This method uses an automatic system developed for the removal of stuck and dead volume heaps. In the hammering method, a timed mechanism, which hits the exchanger modules (10) at certain intervals.

The PH exchanger (1 ) designed in the invention is vertical type (horizontal bundles); this layout has the advantage that the furnace gas is released at high altitude and must be connected to the ID fan located at ground level. In this way, the vertical heat exchanger can be installed parallel to the bottom corner to maximize the impact on the existing layout with possible good impact on capital costs.