CN110392770B

CN110392770B - Method and plant system for energy conversion using carbon dioxide

Info

Publication number: CN110392770B
Application number: CN201880006904.1A
Authority: CN
Inventors: 奚振华
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-04-04
Filing date: 2018-03-24
Publication date: 2022-04-05
Anticipated expiration: 2038-03-24
Also published as: DE102017003238B4; WO2018184612A1; CN110392770A; WO2018184612A4; DE102017003238A1

Abstract

1. A method and apparatus system for energy conversion using carbon dioxide. 2.1 the thermal capacity of carbon dioxide is low compared to water and the materials and equipment used must withstand high pressures and temperatures if allowed to operate in critical and energy density high regions. However, because of its low critical point, one can use it efficiently to convert natural thermal energy into mechanical energy. 2.2 for this purpose, a large amount of carbon dioxide is filled into the container and heated, for example, with the hot climate in summer. Therefore, a foundation is laid for the expansion work of the carbon dioxide in the heat engine. One should smooth out the pressure fluctuations of the carbon dioxide before it expands and continue to heat up as the carbon dioxide fluid flows to the heat engine. After expansion, it can be liquefied by cooling, for example by chilling in the weather to liquefy carbon dioxide. To obtain cold or high temperatures in the climate, regional or time bridging via carbon dioxide transport systems or carbon dioxide storage facilities is required. The carbon dioxide storage system has, in addition to the storage function, a heating and cooling function which must be matched to the power of the heat engine, thus eliminating the contradiction between the slow heat transfer of the heat exchanger and the fast operation of the heat engine. Furthermore, carbon dioxide processes, such as heat transfer, in the storage tanks of a carbon dioxide storage facility are not operated continuously at steady state, but rather batch-wise. Therefore, the carbon dioxide fluid circulation process of the heat engine plant system is a batch-type unsteady-state flow process. 2.3 therefore, the carbon dioxide in the circulating use is like 'natural gas' which can not be burnt, and the heat energy in the nature can be continuously converted into electric energy, thereby economically and effectively solving the problems of climate change and energy shortage, also relieving desertification under certain conditions and eliminating the trouble of haze by the way.

Description

Method and plant system for energy conversion using carbon dioxide

The invention relates to a method and a thermodynamic device system for energy conversion using carbon dioxide as a working medium. It is well known that carbon dioxide can be used for energy storage, particularly when it is near its three phase co-existence, and it takes less volume per megawatt hour to store than compressed air stored in an open coal mine cavern, and also less volume than water stored in a water reservoir. It avoids the restriction of energy storage site selection caused by coal mine caverns or water reservoirs, and the energy stored in the carbon dioxide can be used almost at any time for regulating the load function of the power grid. It is also known that the use of carbon dioxide stored in a container allows the simultaneous conversion of mechanical energy and refrigeration with work and refrigeration coupling, in order to achieve a higher refrigeration efficiency. There are, of course, many other possibilities for utilizing carbon dioxide, and in respect of how the carbon dioxide is obtained, there are also many separation techniques known per se, such as a cryogenic process of the cyclone stage, with which for example biogas can be fractionated, from which carbon dioxide, methane, water and other substances can be separated. In the present invention, it is necessary to utilize carbon dioxide in large quantities to generate high pressure and suitable temperature for the carbon dioxide operation, such as the heat transfer operation in each container of a carbon dioxide thermodynamic plant system, which can be set to be not continuous but batch-type, and the start time and duration of batch-type are somewhat random. The carbon dioxide cycle process thus formed in the carbon dioxide thermodynamic plant system is rather a non-steady-state carbon dioxide flow process.

This is in contrast to the state of the art, i.e., continuous flow processes where the working medium is generally stable, the carbon dioxide flow process of the invention of this patent generally operates unstably and in batch mode in the low temperature region of carbon dioxide. Various general measuring devices, machines, materials, etc. may be used where the present invention is desired. On the other hand, as is known, efforts are also being made to find low-cost materials for the manufacture of mechanical devices and measuring devices, and to make them able to withstand both the high pressure and the high temperature of carbon dioxide. For example, a heat engine model is constructed that expands carbon dioxide in the energy dense region to produce work. It is also known that the invention of steam engines has been dedicated to the careful construction of the engine and to the optimization of the working process in order to achieve a higher thermal efficiency. Of course, when using carbon dioxide as a working medium for energy conversion, the amount of carbon dioxide used up to now is still limited. The present invention will be considered in some respects from the point of view of both the large input of carbon dioxide as the working medium and the low cost of utilizing natural temperature differentials for heating and cooling the carbon dioxide to achieve energy conversion and the integration of the use of common technologies for non-steady state and batch operated carbon dioxide fluid processes. Whereby a large amount of thermal energy of nature can be economically and efficiently converted into mechanical energy. For this reason, in some cases large open areas of land are required for the construction of carbon dioxide storage plants or for the construction of carbon dioxide transport systems, and the calculated difference in enthalpy of the heat engine carbon dioxide is generally low compared to water. But the invention can solve the problems of climate change and energy shortage and resist spreading land desertification under certain conditions. For convenience of describing this patent in detail, one can make the following assumptions: the temperature in winter is below-30 ℃, the temperature in summer is above-30 ℃, and the temperature of river water or other natural cooling objects is not more than-20 ℃. The present invention will be described with the assumption that the method thereof may comprise the following four operation steps.

And (4) collecting carbon dioxide. Carbon dioxide containing gases, such as flue gases from coal power plants or other incineration plants and subjected to purification treatment, contain a certain amount of carbon dioxide, which is about 15% of the mass of the flue gas. In order to obtain heat energy from the flue gas and to further purify the flue gas, for example, heat exchange devices and precipitation devices can be used in winter. In this flue gas, condensate and other deposits occur, whereby the flue gas becomes drier and its carbon dioxide content rises as desired.

And (4) liquefying carbon dioxide. The flue gas treated in the first step is cooled, preferably with winter cold air, to a temperature below-30 ℃. The flue gas is then compressed by a gas compressor so that the partial pressure of the carbon dioxide in the flue gas exceeds the pressure by far 15 bar. Whereby most of the carbon dioxide in the flue gas is separated from the flue gas as a liquid. The separated carbon dioxide liquid will be used first for power production and then directed to a carbon dioxide liquid container in the thermal plant system for storage. Each such container should be filled with carbon dioxide liquid. The remaining flue gas after carbon dioxide separation can also be utilized or treated. It is also important to mention here that other fluids than flue gas but containing carbon dioxide may also be used for separating and liquefying carbon dioxide. The liquefaction of carbon dioxide in a thermodynamic plant system is further described in detail below in the explanation of FIG. 7, which may be used in conjunction with the carbon dioxide separation liquefaction process described herein.

Heating of the carbon dioxide. The carbon dioxide liquid filled in the container is heated by hot air in summer or by other natural heat such as waste heat, geothermal heat and sunlight heat, which may for example be obtained in the second step described above, and which may also be converted into a storage container before heating. Their temperature is raised above 30 degrees celsius by heating, and their pressure can reach a corresponding height of 700 bar or more due to isochoric heating. In addition, the temperature of the carbon dioxide can be increased continuously during the process of flowing the carbon dioxide fluid to the heat engine, and the heat source can be heat energy generated by sunlight heat-collecting equipment or heat energy generated by burning carbon dioxide neutral fuel in an incinerator under certain conditions.

Energy conversion of carbon dioxide. The high pressure carbon dioxide heated in the third step above may be expanded in a heat engine, such as a piston heat engine or a turbine, to produce work, such as for producing electrical energy. The strong pressure fluctuations of the carbon dioxide before it enters the heat engine should be smoothed as much as possible. The carbon dioxide expanded in the heat engine to do work is liquefied again by using low-temperature river water, cold air or other low-temperature objects in the nature, and the carbon dioxide gas may be compressed during liquefaction. The liquefied carbon dioxide then again fills the carbon dioxide vessel completely. The operation thus returns to the third step above, and an expandable carbon dioxide circuit can be formed, if necessary, by the inflow of carbon dioxide, which can be derived from the second step described above.

In each of the above four steps, one tries to use only the heat energy and low temperature of nature, which means that the present invention can be applied to regions with suitable climatic conditions, i.e., regions with cold winter or high temperature summer, such as north of china or egypt, in order to obtain high economic efficiency. Preferably, an area is both winter cold and summer hot.

Explanation of the drawings: the invention will be further explained below with seven figures.

Explanation of fig. 1: the first is a system overview. As shown, the thermodynamic device system comprises a plurality of sets of five components described below: a heat exchange device, a precipitation device, a carbon dioxide liquefaction device, a carbon dioxide thermoelectric device, and a carbon dioxide fluid storage system. The carbon dioxide fluid storage system is called carbon dioxide storage equipment for short, and can also be composed of two sets of sub-equipment, namely carbon dioxide gas storage equipment and carbon dioxide liquid storage equipment. Before the heat exchange equipment, it is assumed that a carbon dioxide containing gas is already present, e.g. purified treated flue gas, which may come from a facility like a coal power plant. In order to cool down the flue gases and to obtain heat therefrom, heat exchange devices can be used, for example, in winter. In this case, cooled flue gas is produced which is then passed to a downstream precipitation plant for precipitation cleaning and where it is further dried by further cooling and in some cases filtered by a dust separator. One can thus obtain a flue gas which is both dry and further purified, which is again cooled deeply and suitably pressurised in a subsequent carbon dioxide liquefaction plant, in order to facilitate the separation of carbon dioxide from the flue gas in liquid form. The carbon dioxide liquid thus separated may be used once for power generation first, and then the container of the carbon dioxide liquid storage apparatus is filled and stored. The carbon dioxide liquid thus stored may be dumped in the future. The carbon dioxide liquid in the container is heated in the coming summer, the heat source can be air heat, solar heat and other natural heat sources, or the carbon dioxide is immediately heated by available heat sources such as various residual heats, geothermal heat and heat generated by burning carbon dioxide neutral fuel and the like before the coming summer, and is sent to a heat engine with a generator to be expanded to work and generate electricity. The gaseous carbon dioxide after the expansion work can be sent to a carbon dioxide gas storage container for storage, and the carbon dioxide gas can be liquefied again by using cold air in the coming winter, or the carbon dioxide can be cooled by using the low temperature of river water or other low-temperature objects similar to the nature in the coming winter to enter a liquid state again.

It is easy to see here that the temperature differences in winter and summer climate are bridged by carbon dioxide storage facilities. Such bridging is known as temporal bridging. Where the carbon dioxide is compressed and liquefied in winter and heated and expanded in summer, between which they can be stored in a carbon dioxide storage facility. In addition, a regional bridge between high and low temperature regions via carbon dioxide transport systems such as carbon dioxide long distance transport pipes or channels is also contemplated. Where the carbon dioxide is liquefied in a cold zone and then sent to a hot zone where it is heated and sent to a heat engine where it is expanded to produce work. And after the expansion work, the carbon dioxide gas is sent back to the cold area through the carbon dioxide transportation system. In addition, the regional bridging of carbon dioxide can be divided into horizontal bridging and vertical bridging, for example, bridging in arctic and equatorial regions is called horizontal bridging, and bridging at the mountain tops and foot bottoms of himalayan mountains is called vertical bridging. Of course, time and area bridging can also be performed in combination. Last but not least, the temperature difference between the air and the river water can also be utilized within one day in the same area.

Explanation of fig. 2: it is known that flue gases from coal power plants or other incineration plants have been subjected to purification and are associated with a certain high temperature. Normally, it is discharged into the atmosphere through a tall chimney, but is now transferred to the heat exchanger of the thermodynamic system. I.e. it is led to the inlet (1) of the heat exchanger device into the metal tubing (5) of the heat exchanger. The metal pipes may be round or flat in shape, placed in a reinforced concrete container and placed from top to bottom, for example in a spiral or linear manner. The reinforced concrete container itself is insulated at a portion of its outer wall by, for example, an insulating material. The flue gas flows from the top to the bottom of the metal pipe and then flows out of the heat exchange device from the gas outlet (2). Cold water flows into the cold water inlet (3) from the top of the reinforced concrete container and flows to the lowest part of the reinforced concrete container through the pipeline to enter the container, then the water flows along or crosses the outer wall of the metal pipeline from bottom to top in the container, and finally the water becomes hot water and overflows out of the container from the hot water outlet (4). The condensation water produced in the metal pipe will also flow out of the heat exchange device together with the flue gas and into the subsequent precipitation device. In addition, the heat exchange device should consist of two such sets of heat exchangers.

Explanation of fig. 3: the gas inlet (6) is connected to the outlet (2) shown in fig. 2. The gas inlet (6) is at a lower level than the outlet (2) so that condensate from the flue gas can easily flow into the reinforced concrete container of the precipitation apparatus. The condensate is taken out under the control of the double valve control door (7) independently, that is, the condensate with some impurities flows to a water treatment device from a water outlet which is not shown in the figure after precipitation, and all precipitated solids are also properly treated after the double valve control door (7) is taken out. The heat exchanger (10) shown in the figure can further cool the flue gases, for example, with winter cold air. The flue gas thereby becomes drier and then flows through a non-return valve (9) towards a gas outlet (8) and into a subsequent carbon dioxide liquefaction plant. If necessary, an air extractor may be provided to extract the gases from the vessel and a gas filter may be provided before the check valve (9) to remove large and light particles from the gases. In addition, the settling apparatus should consist of two such reinforced concrete containers.

Explanation of fig. 4: the operation of carbon dioxide liquefaction will be described here by way of example with a dry flue gas from a precipitation plant. Other gases containing carbon dioxide can also be liquefied in a similar manner. The dry flue gas from the precipitation plant is compressed and pressurized to above 300 bar in a carbon dioxide liquefaction plant, where intermediate cooling can also be carried out with a multistage compressor plant and cold air in winter. The high temperature of the gas produced during compression can reach above 100 degrees celsius, thereby producing two high temperature heat flows a and B that are directed to

heat exchangers

1 and 2. After compression and cooling, the flue gas is in a thermodynamic state at a pressure greater than 300 bar and at a temperature lower than-30 ℃ in winter, which is sufficient to liquefy the carbon dioxide in the flue gas. The compressed flue gas then flows into a previously evacuated container, where it can be cooled further, whereby the flue gas is separated into two parts: carbon dioxide liquid and the remainder, referred to as residual flue gas. The two fractions are then drawn out of the vessel by means of a carbon dioxide stream D and a residual flue gas stream C, respectively, and then heated to above 100℃ by means of

heat exchangers

1 and 2, respectively. The heat source may be heat energy generated by the multi-stage gas compressor, or hot water from the overflow of the heat exchange device, or other available heat sources. The carbon dioxide fluid and the remaining flue gas then flow to one or more heat engines with electric generators, such as piston engines or turbines, where the fluid expands to produce work and to reduce the gas pressure after expansion of the fluid as much as possible. For example, the carbon dioxide fluid may be released to, for example, 15 bar and then introduced into a container of the carbon dioxide liquid storage facility for storage. The remaining smoke can be similarly released to, for example, 1 bar. The remaining flue gas after expansion work can be released to the air or used further, for example by refrigeration during expansion and by separation of oxygen and nitrogen from the remaining flue gas by suitable techniques such as the linde process.

It is thus seen that it is desirable and desirable to make almost entirely cost effective use of purified treated flue gas where a number of important new material forms, such as liquid carbon dioxide and hot water, are present. For this purpose, however, electrical energy is used, for example, to drive the gas compressor. However, the heat generated by the compression of the gas and the heat of the hot water obtained by heat exchange with the flue gas can be used for heating the carbon dioxide and for producing a large amount of electric energy by means of a heat engine, so that there is still surplus electric energy after accounting for the consumed electric energy. However, a large amount of carbon dioxide liquid storage vessels are required for storing the carbon dioxide liquid, which means that a large amount of construction capital is required. However, this capital can be recovered by the heat engine continuing to produce electricity, i.e., in the coming summer, heating the previously stored carbon dioxide liquid to expand it to do work, or before the coming summer, transporting the carbon dioxide to a hot area, or utilizing available waste heat and geothermal heat, etc.

Explanation of fig. 5: the carbon dioxide liquid passes through the carbon dioxide liquid inlet (11) and through the check valve (13) into a pre-evacuated container, which may be a reinforced concrete container with suitable external insulation. If desired, it can also be fed by the pump (12) and, in addition, can flow through a switchable channel, not shown in the drawing, next to the pump (12) to the non-return valve (13). The container may be provided with a heat exchanger (16) for heat transfer from the interior of the container to the exterior of the container, and the container has a carbon dioxide liquid outlet (14) with a check valve (15) and at least one safety valve not shown. When the pressure of the carbon dioxide in the container exceeds a certain value, such as 70bar, the safety valve will automatically open to let the carbon dioxide liquid flow out. The carbon dioxide liquid container can be a plurality of carbon dioxide liquid containers which are communicated through the valve and jointly form a carbon dioxide liquid storage device. The respective heat exchangers (16) of the containers can be provided with different heat exchange powers. For example, some vessels have carbon dioxide fluid flowing directly to a heat engine to be expanded to produce work, and such vessels should be equipped with high heat exchange power. The heat exchange power of other containers can be reduced properly, especially when the heat exchange time of the carbon dioxide liquid in the container is longer, such as storing for several months from winter to summer.

Explanation of fig. 6: carbon dioxide gas is passed through the carbon dioxide gas inlet (17) and through the check valve (19) into a pre-evacuated container, which may be, for example, an externally suitably insulated reinforced concrete container and may be constructed in conjunction with a carbon dioxide liquid storage container. The carbon dioxide gas can be fed by a fan (18) if necessary, and can also flow through a switchable channel, not shown in the drawing, next to the fan (18) to a non-return valve (19). The vessel may be provided with a heat exchanger (22) for heat transfer from the exterior of the vessel, and the vessel may have a carbon dioxide gas outlet (20) with a check valve (21), and the vessel may have at least one safety valve not shown. When the pressure of the carbon dioxide in the container exceeds a certain fixed value, such as 5 bars, the safety valve can be automatically opened to allow the carbon dioxide gas to flow out.

The carbon dioxide gas container can be a plurality of carbon dioxide gas containers which are communicated through valves and jointly form a set of carbon dioxide gas storage equipment. If the container is equipped with a heat exchanger (22) and the heat exchange is carried out for a longer period of time, for example for several months from summer to winter, the heat exchange power should be lower.

Explanation of fig. 7: the carbon dioxide thermoelectric device has a bank of heat engines, which may be piston engines or turbines, each equipped with a generator. The group of heat engines is connected on the left and right to a heat exchanger, respectively, which in turn is connected to a respective operating vessel L or R. The operating container L or R is connected to a container group L1, L2.. Ln or a container group R1, R2.. Rm, respectively, via respective switches. Both sets of containers are connected to the heat source and cold source devices through respective controllable switches. The heat source and cold source devices are also connected to the process vessels R and L and to the heat exchangers connected on both sides, but the corresponding switches and connecting lines are not shown in the figure in order to highlight the main points. All containers can be insulated from the outside, for example by means of insulating material, and the inside can be provided with heat exchangers for heat exchange with the outside. The process vessels differ from the other vessels in that they are designed to have a greater heat exchange capacity and a higher pressure resistance than the other vessels.

The starting conditions of the thermodynamic plant system can be assumed without loss of general versatility: the right containers are all evacuated and the left containers are filled with carbon dioxide liquid and have a high pressure and a certain, suitably high temperature. These two state quantities pressure and temperature are referred to below as operating pressure and operating temperature. In the operating container L, the tensioned carbon dioxide fluid flows through the left-hand heat exchanger, where it is reheated and flows to the heat engine of the thermoelectric power unit. After the carbon dioxide fluid expands in the heat engine to produce work, the pressure and corresponding temperature decrease. The two state quantity pressures and temperatures at this time are hereinafter referred to as a release pressure and a release temperature. The released carbon dioxide is cooled down in the heat exchanger on the right and continues to flow to the operating vessel R on the right.

The vessels L1, L2, Ln on the left will successively supply the carbon dioxide fluid to the operating vessel L, while their carbon dioxide is being supplied, the carbon dioxide in them is being heated by their respective heat exchangers simultaneously. This heating process is called heating for filling or heating for expansion (see claim 1). The end time of the carbon dioxide supply process of each container is determined by a certain carbon dioxide pressure height in the corresponding container, after the carbon dioxide supply process of the container is ended, the container is closed, the heat exchanger in the container is switched from the heat supply process to the cooling process after the container is closed, namely, the cold source is switched on after the heat source is closed, so that the residual carbon dioxide in the container is cooled. The cooling process is terminated when its temperature approaches that of the cold source. This process is called a cooling process for filling (see claim 1). This cooling process for filling takes place sooner or later at certain time intervals in each container of the left-hand group of containers L1, L2.

In the right container of the thermoelectric power unit, the operation container R firstly receives the carbon dioxide after expansion work and opens the cooling process through the heat exchanger of the operation container R. The cooled carbon dioxide continues to flow, either sequentially or in parallel, to the right-hand vessel R1, R2, Rm, and the carbon dioxide continues to be cooled by the respective heat exchanger of the vessel to facilitate liquefaction of the carbon dioxide. The low temperatures necessary for the cooling process come from the attached cold sink devices. After the respective container in the group of containers R1, R2.., Rm is filled with carbon dioxide from the operating container R, this container is closed and the heat exchanger of the closed container is switched over, i.e. the cold source switch of the container is closed and the hot source switch of the container is opened, in order to heat the carbon dioxide enclosed in the container in a constant manner until they reach the initial operating temperature on the left side, whereby the carbon dioxide reaches the initial operating pressure on the left side again in this container. This process will occur within each container in the right container group R1, R2. In this way the carbon dioxide fluid in each vessel of the right-hand bank will sooner or later reach a thermodynamic initial state at start-up of the plant. The cooling process is referred to herein as a cooling process for liquefaction (see claim 1), and the heating process after the vessel is closed is referred to as a heating process for pressure increase (see claim 1).

Immediately or shortly before, the carbon dioxide fluid begins to flow in the opposite direction, i.e., from the right side vessel to the left side vessel of the thermoelectric power unit. The carbon dioxide supply process to the right side vessel is the same as that to the left side vessel. Left-hand containers L, L1, L2.., Ln all have residual carbon dioxide inside them, which after cooling have a pressure lower than the release pressure. Therefore, the carbon dioxide filling, cooling and heating processes are the same as those in the right container as described above. Whereby the carbon dioxide sooner or later returns to the thermodynamic state at start-up of the plant.

The container structures on the left and right sides of the thermoelectric generator set are similar in the figure. The flow direction of carbon dioxide in the above described process alternates constantly from left to right and from right to left at certain time intervals. Similarly, heating and cooling of carbon dioxide, and supply and filling of carbon dioxide are also alternately performed in the containers on both sides, and the containers are also alternately switched between the open and closed states, respectively. In addition, the flow process in each vessel is not continuous, but batch-type, and the start-up of the batch and the duration of the start-up have some randomness. Therefore, the carbon dioxide flowing process is not a steady-state flowing process and is more like a ping-pong transient flowing process at the left side and the right side of the heat engine unit. This flow process is described in more detail below with specific numerical values added to the example model to be described below. It is also noted here that the contradiction between slow progress of heat transfer in the heat exchanger and fast operation of the thermal power machine is solved by the flexible arrangement of the storage, heating and cooling functions of the carbon dioxide container.

Example model: various standard techniques and equipment are generally integrated into the present invention.

A heat engine: they may be piston engines or turbines with generators and operate at different carbon dioxide pressures and temperature intervals, the highest value of which may be 700 bar and the lowest and highest values of which may be 70 c below zero and 150 c above zero, respectively. The upper pressure limit of 700 bar depends on the compressive strength of the carbon dioxide vessel, which can well exceed 700 bar, e.g. 2000 bar, when the carbon dioxide is isochorically heated to 150 ℃ in the vessel. The container can therefore be made of a material of high strength, if necessary, for handling, so that the container can withstand higher pressures, for example 1327 bar, and at the same time a temperature of 80 ℃. The setting of the carbon dioxide release pressure depends on the ambient temperature, such as the temperature of river water, and it also depends on the operational objective of the heat engine, such as power generation or refrigeration. It is also affected by the density ratio before and after expansion of the carbon dioxide. The lower temperature limit of the carbon dioxide after expansion in the heat engine is limited not only by the release pressure but also by the temperature of the three-phase co-existence point of the carbon dioxide and other factors such as the entropy height and the strength of the material used. The upper temperature limit of the carbon dioxide before it is released in the heat engine can be set between 20 and 150 degrees celsius in order to heat the carbon dioxide as far as possible without the use of fossil fuels, while at the same time converting the large amounts of thermal energy of nature into mechanical energy economically and efficiently.

The gas compressors used for compressing flue gas or carbon dioxide gas are usually operated here at between 20 and 400 bar, and today's gas compressor technology is fully capable of achieving such pressure requirements. Furthermore, if other processes such as Membrane Gas Separation (MGS) or Pressure Swing Adsorption (PSA) are used to increase the carbon dioxide content of the flue gas prior to compression of the flue gas, the upper pressure limit of 400 bar can be much lower. Whether one or the other of these two techniques is to be used depends entirely on economic considerations.

The instruments for measuring pressure, temperature and flow are standard devices for which there is generally no high precision requirement, that is to say tolerance tolerances in the range of one tenth of the unit of measurement, such as pressure bar, temperature, cubic meters flowing out per minute, etc.

Current heat exchange technology is also considered to be technically mature and capable of meeting the heat exchanger requirements of the present thermodynamic device system. Reference is made herein to the product specifications of the relevant company and to the corresponding text books mentioned in the description of the invention.

If carbon dioxide is delivered remotely, one can use a reinforced concrete channel to deliver carbon dioxide gas, which requires a pressure of about 5 bar. In the tunnel or directly adjacent to it or elsewhere one can build a carbon dioxide liquid pipeline, which is subjected to a pressure of about 30 bar of carbon dioxide. The requirements of this carbon dioxide transport system are fully met by the current pipeline and channel technology, see the corresponding technical literature listed in this specification.

If a carbon dioxide transport system is not used to bridge the hot and cold zones, the site selection of the project may be somewhat affected by the climatic conditions. As a good site selection example, it is the province of Heilongjiang province of China, Harbin city. The temperature in winter can reach 35 ℃ below zero, and the temperature in summer exceeds 30 ℃. It is also preferable that the carbon dioxide thermal plant system be constructed at the source of the carbon dioxide, such as in a coal power plant. However, if there is no land available to build a carbon dioxide storage facility, one can separate and liquefy the carbon dioxide from the flue gas on site and then send it to a remotely built carbon dioxide liquid storage facility via a carbon dioxide liquid transfer pipeline. Such carbon dioxide storage facilities should be built in places where human smoke is scarce, for example, in deserts. Since the carbon dioxide storage facility requires a large area of land or a huge volume, it is possible to also resist spreading land desertification by constructing such a storage facility as a reinforced concrete container. In addition, the carbon dioxide storage facility can be constructed in a modular manner, from small to large to a unit size, which can meet the local energy demand, but in the first place there is sufficient carbon dioxide available. In the case of Halsbane, approximately 258 million tons of carbon dioxide are now available for use a year. For this purpose, it is necessary to construct carbon dioxide liquid storage vessels which have a total volume of about 330 ten thousand cubic meters for storing carbon dioxide liquid having a density of 782.6 kilograms per cubic meter. If the volume of a single container is 17500 cubic meters, 189 such containers need to be constructed. For reliability, one can construct 380 such carbon dioxide liquid storage containers, and as shown in fig. 7, 190 such containers are disposed on each of the left and right sides of the thermoelectric power unit: 1 operating vessel and 189 other vessels. Assuming that the average total flow rate of carbon dioxide fluid through the thermal power plant is 2000 tons per second, 258 million tons of carbon dioxide can be continuously supplied for about 10 days to flow from one side of the thermal power plant to the other side of the thermal power plant, and then flow in the opposite direction.

In consideration of economic benefits, the thermodynamic equipment system invested in construction is low in scale. Taking harbourne as an example, it is believed that it requires approximately a coal fired power plant with a total generated power of 2GW to meet civil needs. Thus consuming about 641 million tons of standard coal per year, producing about 2061 million tons of carbon dioxide. Assuming an efficiency of 75% for the separation of carbon dioxide from flue gas, it is possible to separate 1546 million tons of pure carbon dioxide from flue gas per year, and if cold air below-30 ℃ is used only during the winter months in one year, one can liquefy 258 million tons of carbon dioxide per year. But also to transport them to places far from the urban area where the human smoke is scarce and to store them by means of carbon dioxide transfer pipelines, where carbon dioxide liquid storage facilities are built. The total investment of about 9 billion yuan RMB is needed for the equipment system, and the construction cost of land and carbon dioxide conveying pipelines is not included. A major part of the total investment falls into the construction of the carbon dioxide storage facility, i.e. the construction of 380 of the above-mentioned carbon dioxide vessels. In order to heat carbon dioxide in summer, a solar heat collecting system and a hot salt heat storage system can be used besides hot air, and carbon dioxide neutral fuel can be combusted by an incinerator under certain conditions in other seasons to ensure that the carbon dioxide enters a thermal power machine after the operating temperature of the carbon dioxide reaches 80 ℃ below zero. The release pressure is set at 60 bar, which depends on the ambient temperature, for example 20 ℃ river water. The thermal efficiency of the heat engine is assumed to be 70% during the thermal-power conversion, and the difference value of the enthalpy of the carbon dioxide heat engine before and after expansion work is 21 kilojoules per kilogram on average. It can achieve a higher difference in enthalpy under more favorable conditions, such as about 118 kilojoules per kilogram. The following power generation calculations were performed at 21 kilojoules per kilogram so that one could obtain approximately 28 megawatts of electrical power. It can thus be derived: a) 2.44 billion degrees of electricity are produced in the first year, b) a certain amount of refrigeration is obtained in summer. Currently, the price of the environmental protection electricity in China is about 0.5 yuan RMB per degree of electricity. Thus, only the electricity income can obtain 1.22 hundred million yuan, which is very significant in economic benefit compared with the estimated investment of about 9 hundred million yuan.

The operation of this carbon dioxide thermal plant system is described in detail below and will be described with reference to fig. 7 and harbourne as an example. First, without being limited by a general condition, one can assume the following initial state: as shown in fig. 7, the right container of the thermoelectric power unit is empty, and the left container is filled with carbon dioxide fluid, and the thermal state of the thermoelectric power unit is 342 bar and 80 ℃, so that the density of the thermoelectric power unit is 782.6 kilograms per cubic meter; the coolant is assumed to be river water, and the temperature of the coolant does not exceed 20 ℃; the total heat transfer power of all heat exchangers of the thermodynamic device system must correspond to 28 megawatts of the power generated by the system, which requires approximately 215 megawatts of heat transfer capacity for heating of the carbon dioxide and 270 megawatts for cooling of the carbon dioxide. It should also be mentioned in these assumptions that a reinforced concrete vessel which is resistant to 342 bar pressure is a very demanding requirement. The following 9 notes, particularly the fourth note, can be used to explain how the pressure resistance requirement of the vessel can be greatly reduced without reducing the generated power. At the beginning of the process, the tensioned carbon dioxide fluid flows from the left operating container L, after reheating in the left heat exchanger, to some of the heat engines in the thermoelectric power plant, where it expands to work and is released to 60 bar. The released carbon dioxide fluid flows into the right operation container R after being cooled by the right heat exchanger.

When the carbon dioxide flows out of the left operating container L, the heat exchanger of the container L turns on the switch of the heat source equipment, so that the carbon dioxide in the container obtains heat and can rise to the temperature of more than 80 ℃. While its operating pressure may be reduced as the carbon dioxide exits the vessel L. When the pressure drops to around 70bar, the vessel L1 starts supplying carbon dioxide fluid to the operating vessel L. At the same time, the heat exchanger of the container L1 is switched on and off from the heat source device, so that the carbon dioxide in the container gets heat and raises the temperature to 80 ℃ or higher as much as possible. When the carbon dioxide pressure in container L1 had dropped to around 70bar, container L1 was closed and slightly before this closing, L2 started supplying carbon dioxide fluid to the process container L, while the heat exchanger of container L2 was switched on its switch from the heat source equipment, so that the carbon dioxide in the container got heat and increased to above 80 c as much as possible. When the carbon dioxide pressure in vessel L2 dropped to around 70bar, vessel L2 closed. This carbon dioxide supply process is thus repeated in the left vessel until the carbon dioxide in the last vessel Ln reaches a pressure of 70 bar. Furthermore, each container of the left container group is switched on and off its heat exchanger as soon as it is switched off, i.e. from a heating process to a cooling process, in order to cool down the remaining carbon dioxide in the container, and the cooling processes of the left container group L1, L2. The cooling process in each left container continues until the remaining carbon dioxide in the container reaches a temperature near the local cold source temperature, such as 20 c. The low temperature comes from the cold source equipment connected with the heat exchanger of the respective container.

The operation of the carbon dioxide on the left side is described above, and the operation on the right side will now be described. The operating vessel R receives the carbon dioxide after expansion to work and cools it down by its own heat exchanger. The reduced temperature carbon dioxide then flows to vessel R1 and R1 begins to receive carbon dioxide and continue to reduce its temperature using its own heat exchanger. When the carbon dioxide in R1 reaches the release pressure of 60 bar due to the carbon dioxide filling of R, the non-return valve of R1, not shown in fig. 7, automatically closes, at the same time or shortly before the carbon dioxide from the operating vessel R starts to fill the vessel R2. Thus, similarly, this process will continue until the last container Rm of the right set of containers. When carbon dioxide is delivered to the container R2 or the containers with the number of the containers of the right container group being more than 1, the temperature of the carbon dioxide in the container R1 is continuously reduced by the heat exchanger until the temperature of the cold source reaches 20 ℃. Furthermore, as soon as the carbon dioxide pressure in the container R1 is below 60 bar, the carbon dioxide from the container R will automatically refill R1 until its carbon dioxide again reaches the release pressure of 60 bar. This refilling of R1 is repeated at intervals until the carbon dioxide in the container R1 reaches a steady thermal state of 60 bar and 20 ℃. From this state it can be derived that the density of carbon dioxide in the vessel is 782.6 kg per cubic meter. The vessel R1 is then closed and its heat exchanger is switched from a cooling process to a heating process. Thereafter, isochoric heating of the carbon dioxide in R1 via the heat exchanger of R1 was started until it reached an operating temperature of 80 ℃. It follows that the pressure of the carbon dioxide in the container R1 is 342 bar. Similarly, the carbon dioxide in this container R1 operates: the cooling, filling and heating of the carbon dioxide will be performed sequentially or in parallel in each vessel of the right bank. When the carbon dioxide tension in the last container Ln on the left drops to 70bar, i.e. all the carbon dioxide tension on the left is used up by the work of expansion in the heat engine, the carbon dioxide in the last container Rm on the right or in the containers of a previous container group on the right has reached a steady thermal state of 342 bar and 80 ℃. At this point, the overall flow of carbon dioxide fluid begins to reverse, i.e., flow from the right container to the left carbon dioxide container. The supply of carbon dioxide in the right container is identical to that of the left container described above, i.e. the tensioned carbon dioxide flows from the operating container R, is reheated by the right heat exchanger and flows to some of the heat engines of the thermoelectric power unit, where it is expanded to 60 bar. The released carbon dioxide is cooled by the heat exchanger on the left and can easily enter the left-hand process vessel L, since the carbon dioxide in the process vessel L, owing to the preceding cooling, has reached a thermal state of 20 ℃ and a density of 134.1 kg per cubic meter, which means that its pressure is approximately 48 bar, which is less than 60 bar. The containers of the left container group are now repeated with the previously described process of receiving carbon dioxide in the right containers, i.e. filling, cooling and heating, etc. The carbon dioxide fluid in each container to the left thus returns to its thermodynamic initial state of 80 c and 342 bar sooner or later within a certain period of time.

As described above, the carbon dioxide supply process is performed first from left to right, then from right to left, and now from left to right. In the repeating period, the ping-pong continuous flow reciprocating process of the carbon dioxide back and forth between the left and the right of the heat engine set is realized. However, it is not forbidden to ask whether the heat engine will have intermittent periods of shutdown, because the supply and reception process of the left and right operating containers and the switching process of the cold and hot are slow. The solution to this problem can be found in the following remarks, which one can imagine for the moment that one operating container can consist of two sub-containers: one to receive and cool the carbon dioxide and the other to supply and heat the carbon dioxide. Similarly, it is also conceivable that the heat engine and the heat exchangers on both sides of the heat engine block are of similar composition.

Note that:

1) for better understanding, diagram 7 of the carbon dioxide thermal plant system is drawn almost symmetrically. In fact, only one system control program is needed, which regulates the corresponding carbon dioxide operation process and the heat transfer mode of the heat exchanger according to the state of all containers and heat exchangers in the system. That is, regulating their turning on and off, regulating the heating, cooling, stopping, supplying, filling and refilling of carbon dioxide, regulating the turning on and off of the container, and regulating the switching of the heat exchange mode such as the turning on, off, on and off of the heat exchanger and the heat source and cold source devices. All containers L, L1, L2.., Ln and R, R1, R2.., Rm are also under the control of the same system control program. This makes it possible to fix one operation vessel for supplying carbon dioxide and the other operation vessel for receiving carbon dioxide. In the same way, the heat exchangers on both sides can be fixed for heating or cooling carbon dioxide. In addition, heat exchangers fixed for cooling on the heat engine side may also be incorporated with the process vessel receiving carbon dioxide. And the other carbon dioxide vessels except the operation vessel are not heated in time, and the temperature is lower than the set operation temperature such as 80 ℃ in the example model, so that the supply process can be stopped. The supply of carbon dioxide to the carbon dioxide-supplying process vessel can then be continued by another suitable carbon dioxide vessel, i.e. a carbon dioxide vessel having a carbon dioxide temperature and pressure within the set ranges, which in the example model means that the carbon dioxide temperature is greater than or equal to 80 c while its pressure exceeds 70 bar. The carbon dioxide vessel other than the process vessel does not necessarily need to have sufficient heat exchange capacity for heating and cooling of the carbon dioxide. It must be noted, however, that the total heat exchange power of the carbon dioxide heating and cooling of the thermodynamic device system must match the designed power generation power. For example, the above-mentioned harbourne city example model is set to an electrical power of 28 megawatts, and the total heating and cooling power must be of the amount as described above. Therefore, no matter what specific programming language and hardware are used for realizing the regulation function of the system control program, the number of 380 containers can be obviously reduced on the premise of ensuring that the volume of a single container is not changed, and the corresponding investment can be reduced. Finally, it can be seen from the above power ratios that the thermal efficiency of the system is about 13% and 6% respectively with respect to the total power of the heating power or heat exchange. This efficiency is similar to the efficiency of the ORC (organic Rankine cycle) system in the low temperature range.

2) As mentioned previously, the example model of harbourne has a sufficient amount of carbon dioxide for a single supply of carbon dioxide to the thermal unit, causing them to expand in the thermal engine to work for up to 10 days. If the flow of carbon dioxide is increased, for example, by a factor of two, i.e. 4000 tons per second, the time can be reduced to, for example, 5 days. The generated power will thus be increased by about one time, but the heat exchange power and the generated power of the equipment will be increased by about one time accordingly. The minimum duration may be reduced to 24 hours, so that at least in the early morning, the minimum ambient temperature of the day is available for cooling of the carbon dioxide. Here again, it is recognized that the time bridging function of the container, i.e. the time for cooling the carbon dioxide by storing it in the container, i.e. the time for receiving carbon dioxide gas from the handling container, is shifted to a later time by storing it in another container, e.g. in the coming morning. Similarly, one can move the cooling time of carbon dioxide not only to one or more days, but also to several months, for example from summer to winter. If the time bridging in winter and summer is truly realized, the release pressure in the example model can be greatly reduced by 60 bars, so that the power generation capacity and the refrigeration effect in summer are remarkably improved. However this requires more carbon dioxide storage capacity to be built. On the other hand, on the premise of keeping the generating power unchanged, for example, 28 mw in the example, one can obviously reduce the storage capacity of the carbon dioxide through the reduction of the period, that is, on the premise of keeping the volume of the container unchanged, the number of 380 storage containers in the example can be greatly reduced. The total investment of the system in the example is thus significantly reduced by 9 billion dollar banknotes.

3) Similar to time bridging, it bridges the temperature difference between high and low temperatures at different times through the container storage function, and one can also bridge the temperature difference between hot and cold regions through a carbon dioxide transport system, such as through a carbon dioxide remote transport pipe or passageway. By regional bridging one can reduce the release pressure of carbon dioxide expanding in the heat engine to do work and increase its operating temperature, thereby increasing power generation. However, for this reason, the construction costs of carbon dioxide transport systems are borne. Furthermore, regional bridging can of course also be used in combination with temporal bridging.

4) If the total heat exchange power of the thermodynamic device system is concentrated in a few carbon dioxide vessels, the remaining vessels need not be equipped with heat exchange power, except for the operating vessel. These remaining containers have mainly a storage function and sometimes an insulation material is installed on their outer walls, whereby they sometimes also have an insulation function. Their compressive strength can be significantly reduced, for example the pressure resistance of carbon dioxide liquid storage vessels can be reduced to seventy bar and the pressure resistance of carbon dioxide gas vessels can be reduced to one bar. The construction and operating costs of the vessel can thereby be further reduced.

5) If refrigeration is the primary objective rather than electricity generation, the carbon dioxide release pressure of some heat engines in the thermal train may be minimized, for example 1 bar, under constraints that take into account the amount of carbon dioxide entropy. The low temperature generated by the carbon dioxide gas released here can be conducted to a place where it is needed. After the introduction of the cryogenic temperature, the carbon dioxide gas can be stored and later liquefied or suitably compressed by a produced electrically driven gas compressor while being converted again to a liquid state by cooling of river water or similar natural cooling bodies. The high temperature heat generated by compression can in turn be used to heat carbon dioxide to facilitate power generation.

6) If excess grid power is available at night, the pressure released by some heat engines in the thermal power unit can be reduced as much as possible during the day to facilitate more power generation and refrigeration, but the limitation of the carbon dioxide entropy is considered. The carbon dioxide gas after the expansion work is properly compressed by a compressor driven by surplus electric power at night, is cooled and then is liquefied again, and the required low temperature can come from the refrigerating process in the daytime or from other natural cooling bodies such as river water, cold air and the like. In the daytime of tomorrow, people can utilize liquid carbon dioxide to generate electricity, and the compression heat energy generated at night can also be used for heating the carbon dioxide. The overall efficiency of the whole process is considerable, and the load regulation capacity of the carbon dioxide driven heat engine is much stronger than that of the water vapor driven heat engine.

7) If the operating pressure is to be equalized, i.e. the fluctuations in operating pressure are to be smoothed, for example by the difference between 342 bar and 70bar in the example model, a carbon dioxide mixing device can be provided for mixing the carbon dioxide jets at different pressures, which is essentially composed of a nozzle and a diffuser, before the carbon dioxide enters the thermal engine block. Alternatively, a large carbon dioxide pressure interval is suitably divided into several small pressure intervals, and each small pressure interval is provided with a corresponding heat engine. Of course, the two methods described above may be used in combination. A completely different approach is to use a back pressure turbine which receives jets at a plurality of pressures and the density of the carbon dioxide jets is in a suitable subcritical region, e.g. less than 60 bar and greater than 80 c, before entering the heat engine.

8) The assumed operating temperature in the implementation model is 80 ℃, which means that relatively cold objects can be used for the first heating of carbon dioxide. For example, hot ambient air in summer may heat the carbon dioxide to 30 ℃ or higher. If the operating temperature of 80 ℃ cannot be reached and the release temperature of carbon dioxide cannot be reduced accordingly, the enthalpy gradient of carbon dioxide is reduced and the power generation power is reduced. However, if the release temperature can also be reduced, the enthalpy gradient may even be increased despite the lower operating temperature. For example, for an operating temperature of 30 ℃ and a temperature of the cooling body of-30 ℃, i.e. the temperature of the air initially assumed by the invention to be available in the summer and winter, the corresponding difference in enthalpy can reach about 36 kilojoules per kilogram. It is much higher than 21kJ per kg in the above example, but this requires time or regional bridging between 30 ℃ and-30 ℃. In addition, a solar heat collecting equipment system can be used, and the solar heat collecting equipment system can provide an operating temperature of 80 ℃ at least in summer. Furthermore, heat can be transferred to the carbon dioxide by combustion of carbon dioxide neutral fuels such as wood waste and straw, which can easily exceed 80 ℃. This type of combustion can even reduce the greenhouse effect of carbon dioxide if the flue gases produced by such neutral fuels are collected, as described above from coal power plants.

9) If the difference in enthalpy used to drive the heat engine is too low, as in the example model of 21 kilojoules per kilogram, only the tensioned carbon dioxide mass of the high pressure section of the operating pressure interval can be taken. For example, in an example one may take only carbon dioxide from the pressure interval of 100 to 342 bar instead of from 70 to 342 bar, thereby increasing the difference in enthalpy by about 10%. Furthermore, the upper limit of the operating pressure may be higher than 342 bar, for example 700 bar, and higher enthalpy gradients of carbon dioxide may also be achieved. But in both cases it is necessary to provide more carbon dioxide or to build a more robust handling vessel etc.

Based on the implementation model of Harbin City and the nine notes mentioned above, one can make various types of extensions and improvements. For example, if the operating temperature is increased from 80 ℃ to 100 ℃, the difference in enthalpy for 21kJ/kg in the implementation model may be increased to about 42 kJ/kg. Similarly, when the coolant temperature, such as river water temperature, drops from the example assumed release temperature of 20 ℃ to 5 ℃, its difference in enthalpy can rise to about 35 kJ/kg. Accordingly, when the operating temperature is increased to 150 ℃ and the coolant temperature is decreased to-30 ℃, the difference in enthalpy will increase dramatically to about 118 kJ/kg. And indeed this variation can be achieved by temporal bridging or regional bridging. For example, if sufficient funds can be raised for the construction of a large carbon dioxide gas storage facility, the passage of time from summer to winter can be achieved by time bridging. More electricity can thus be produced and the total difference in enthalpy can even reach several hundred kJ/kg by technically repeated intermediate reheating. Similarly, large increments in enthalpy difference can also be achieved by using a carbon dioxide delivery system, such as a transfer pipe or tunnel, for regional bridging of carbon dioxide. It is important here that the situation-specific analysis, careful planning and optimization is carried out in order to achieve the highest profitability. Therefore, people can economically and efficiently convert energy by utilizing the carbon dioxide, solve the problems of climate change and energy shortage and resist spreading land desertification under certain conditions.

List of reference numerals

1-gas inlet	2-gas outlet
		3-Cold Water Inlet	4-hot water outlet
5-Metal pipeline	6-gas inlet
		7-double valve	8-gas outlet
9-check valve	10-Heat exchanger
		11-carbon dioxide liquid inlet	12-pump
13-check valve	14-carbon dioxide liquid outlet
		15-check valve	16-heat exchanger
17-carbon dioxide gas inlet	18-air pump
		19-check valve	20-carbon dioxide gas outlet
21-check valve	22-Heat exchanger

Patent document

General literature

1. Thermodynamics, 6 th edition, Press Springer Verlag 2007, author Klaus Lucas

2. Thermodynamics, 15 th edition, press Springer Vieweg 2012, by Baehr and Kabelac

3. Thermodynamics, Vol.1, 19 th edition, Press Springer Vieweg Verlag 2013, authors Peter Stephan, Karl Heiz Schaber, Karl Stephan, Franz Mayinger

4. Technical thermodynamics, 2 nd edition, press Springer Vieweg Verlag 2015, authors

And Matthias Stripf

5. Thermodynamics, 2 nd edition, Press DE Gruyter 2016, Author Muller

6. Thermodynamics of mechanical Engineers, 5 th edition, Press Springer Vieweg 2015, authors wolfgarg Geller

7. German Industrial thermodynamic data sheet, 11 th edition, Press Springer Vieweg Verlag 2013

8. Heat exchanger, 5 th edition, Press Vogel commercial 2015, author Walter Wagner

9. Basic thermodynamic equation, Shaker Verlag 1998, author Reiner Tillner-Roth

10. Multiparameter thermodynamic equation of state, Springer Verlag 2000, author Roland Span

11. Basic knowledge of gas valves, 3 rd edition, publisher Hanser 2012, author Horst-W. Grollius, et al

12. Refrigeration technology edition, 19 th edition, press c.f. muller, heidelberg 2008, author Walter Pohlmann

13. Fluidics apparatus, 5 th edition, publisher Hanser 2013, author Herbert sign loch

14. Architecture, 5 th edition, press Springer Vieweg 2015, author Peter Bindsei

15. Reinforced concrete Structure, 9 th edition, Press Springer Vieweg 2013, author Stefan baby, Karsten Ebeling, Gottfried CO Lohmeyer

16. Evaluation of thermal economics of ORC plants with industrial cogeneration, Verlag Berlin 2014, thermodynamic energy-environmental-technology, Vol.25, author MarkusPrei β inger

17. CCS technology for carbon dioxide, Springer Vieweg 2015, author Manfred Fischedick,

Margit Thomeczek

18. can carbon dioxide be substituted for water vapor for power generation? Scientific American can^TM,By Umair Irfan,Climate Wire,on March 3

19. Analysis of the development stages of the carbon dioxide separation cycle, Cuvillier, Press, Johannes Kremer, Cuvilier, St.A 2014

20. Concerning natural gas and energy (Gas2energy. net), 1 st edition, Press Deutscher Industrieverlag GmbH 2015, authors Jens Mischner, Hans-Georg Faold, Jurgen Heymer, Volker Trenkle

21. Dictionary of gas Engineers, Deutscher Industrieverlag GmbH 2013, authors Klaus Hofmann, Rainer Reibert, Bernhard Klocke

Claims

1. A method for energy conversion using carbon dioxide as a working medium for a heat engine, characterized in that a thermodynamic plant system required for performing the method comprises a heat exchange plant, a precipitation plant, a carbon dioxide liquefaction plant, a carbon dioxide storage plant and a carbon dioxide thermoelectric plant:

the heat exchange apparatus includes: at least one container having a volume of at least 27 cubic meters, the outer wall of the container being partially or completely insulated; at least one metal pipe (5) placed from the top to the bottom of said vessel for flowing high temperature flue gas containing carbon dioxide from the top (1) to the bottom of the metal pipe; a gas outlet (2) arranged in the region of the outer wall of the bottom of the vessel for the flow of flue gas through the metal pipe out of the vessel; an input port provided at a lower portion of the container, the input port being connected to a cold water inlet (3) at an upper portion of the container through a water pipe, so that cold water flows into the container through the cold water inlet, the water pipe and the input port, heat exchange is performed on the surface of the metal pipe, and the cold water is converted into hot water; a hot water outlet (4) arranged in the region of the upper wall of the container for the hot water in the container to escape;

the precipitation apparatus comprises: at least one vessel having a volume of at least 27 cubic meters, the vessel having an inclined bottom for collecting sediment in a fluid containing carbon dioxide; a gas inlet (6) in the region of the wall; a double-layer valve (7) located at the lowest layer of the vessel for withdrawing fluid deposits; an outlet in the wall for draining condensed water from the fluid; a heat exchanger (10) mountable above the interior of the vessel for cooling the carbon dioxide containing gas; an outlet (8) for the exhaust gas and a non-return valve (9) located in the upper part of the container; a fan or dust filter mountable at the gas outlet (8) for filtering the incoming gas;

the carbon dioxide liquefaction apparatus includes: at least one gas compression device with a switchable bypass; at least one vessel for outputting liquid carbon dioxide and a residual gas, respectively, by receiving and cooling compressed carbon dioxide-containing gas, said carbon dioxide-containing gas being a flue gas from a gas compression plant; a set of heat exchangers for transferring heat of compression or other available heat from the gas compression equipment and heating the liquid carbon dioxide or residual gas; a group of heat engines with generators for expansion work of carbon dioxide fluid or residual gas; a vessel for receiving a carbon dioxide fluid after expansion to produce work; a set of carbon dioxide vessels for storing carbon dioxide fluid from a vessel receiving carbon dioxide fluid after expansion to produce work;

the carbon dioxide storage device comprises a carbon dioxide liquid storage device and/or a carbon dioxide gas storage device;

the carbon dioxide liquid storage apparatus includes: a set of containers interconnectable by valves, each container having: a carbon dioxide liquid inlet (11); a carbon dioxide liquid outlet (14); at least one safety outlet valve; wherein the outer wall of the container may be partially or completely thermally insulated and the container is subjected to a pressure of at least 20 bar;

the carbon dioxide gas storage apparatus includes: a set of containers interconnectable by valves, each container being provided with: a carbon dioxide gas inlet (17) with a check valve (19); a carbon dioxide gas outlet (20); at least one safety outlet valve; wherein the outer wall of the container is partially or completely insulated or uninsulated, the container being subjected to a pressure of at least 1.2 bar;

the carbon dioxide thermoelectric device comprises: a group of heat engines with generators, called thermoelectric units; the heat source equipment is used for supplying heat to all heat exchangers of the carbon dioxide thermodynamic equipment system; the refrigeration equipment is used for cooling all heat exchangers of the carbon dioxide thermodynamic equipment system; at least two operating vessels for supplying carbon dioxide to the heat engine and for receiving carbon dioxide from the heat engine, the operating vessels being equipped with heat exchangers, which are in turn connected to a heat source and a refrigeration device by means of a changeover switch; wherein one or more heat exchangers are installed before the operation container for supplying the carbon dioxide, which are connected to the heat source system or the refrigerating apparatus through the changeover switch, and one or more heat exchangers are installed after the operation container for receiving the carbon dioxide, which are connected to the heat source system and the refrigerating apparatus through the changeover switch; a set of containers for supplying carbon dioxide and a set of containers for receiving fluid carbon dioxide, the carbon dioxide containers being equipped or not with heat exchangers, which are in turn connected to a heat source device and a refrigeration device, respectively, by means of switches;

the method comprises the following steps:

using a large amount of carbon dioxide, at least 5000 tons of carbon dioxide in mass as a working medium;

heating carbon dioxide, where the heat of the climate, waste heat, geothermal heat, solar heat or other natural heat, or the heat generated by the combustion of carbon dioxide neutral fuel can be used;

cooling carbon dioxide, where the cooling of the climate, river water, deep soil, deep sea water or other natural cooling, or expansion cooling that may occur in a heat engine, may be used;

the utilization modes of hot climate or cold climate are three: on-site, using a carbon dioxide transport system or using a carbon dioxide storage facility,

the heating process of carbon dioxide in some of the carbon dioxide containers is performed in batch, the cooling process of carbon dioxide in some of the carbon dioxide containers is performed in batch, the charging process of carbon dioxide into some of the carbon dioxide containers is performed in batch, and the extracting process of carbon dioxide from some of the carbon dioxide containers is performed in batch;

the carbon dioxide utilization process in a thermodynamic plant system has the following four steps, and the quality of the carbon dioxide may also increase during the process:

collecting carbon dioxide, and cooling the fluid containing carbon dioxide by using low temperature;

liquefied carbon dioxide, the cooling process for filling and the cooling process for liquefaction being operable in parallel or sequentially in certain carbon dioxide vessels;

heating carbon dioxide, heating for filling, cooling for filling and heating for boosting can be run in parallel or in succession in a container of some carbon dioxide;

and (3) carbon dioxide energy conversion is carried out, and the pressure fluctuation of the carbon dioxide is reduced in the heating process before the carbon dioxide flows into the heat engine to be expanded to do work.

2. The method of claim 1, wherein the method of energy conversion using carbon dioxide requires a large amount of carbon dioxide from flue gas of coal-fired power plants and other combustion equipment, and wherein:

after passing through the heat exchange device and the precipitation device, the fluid containing carbon dioxide, such as flue gas, is dried and purified by utilizing the climate cold or other natural cooling, so that the content of the carbon dioxide in the fluid is increased;

the described climate cold or other natural cooling material or low temperature produced by gas expansion can be used for cooling when the gas is pressurized or for cooling in middle zone;

before the flue gas is compressed in the carbon dioxide liquefaction equipment, the content of the carbon dioxide in the flue gas is increased by using a pressure swing adsorption method or a membrane gas separation method.

3. The method according to claim 2, in the energy conversion with carbon dioxide, the following three types of thermal energy are utilized separately or simultaneously:

heat from flue gas or other waste heat;

heat of compression from a gas compression plant;

the compression energy required when the carbon dioxide is separated by the carbon dioxide liquefaction equipment is used for producing electric energy by the heat engine, low temperature is produced along with work done by expansion of the heat engine, and the produced low temperature is used for one of the following: cooling the gas to be compressed; a mid-section cooling of the gas compression apparatus; recovering pure substances such as oxygen and nitrogen in the residual gas after the carbon dioxide separation; indoor air conditioning.

4. The method of claim 1, wherein the energy conversion using carbon dioxide is a method of generating high pressure of carbon dioxide using two properties of carbon dioxide tension and density, characterized in that:

some carbon dioxide containers are filled with carbon dioxide fluid and are closed after filling;

the carbon dioxide fluid contained in the container can be transferred to another container after being closed and opened again, and then closed again;

the closed carbon dioxide fluid is heated in an isochoric mode, the heat source is preferably waste heat or natural heat energy comprising climate heat, solar heat and terrestrial heat, the heat energy generated by carbon dioxide neutral fuel can be used in some cases, and the heat energy generated by fossil fuel can be used in emergency.

5. The method according to any one of claims 1 to 4, for energy conversion using carbon dioxide, characterized in that:

some carbon dioxide vessels are equipped with heat exchangers;

in the carbon dioxide vessel equipped with a heat exchanger, the heating or cooling process of carbon dioxide is carried out batchwise in each vessel, which may be operated in parallel or successively;

the carbon dioxide filling and extraction processes of the carbon dioxide vessels are carried out batchwise in the respective vessels, which may be operated in parallel or successively;

the carbon dioxide flow process in the carbon dioxide heat engine equipment system can be carried out through regulation and control of a state and process control system in certain containers and heat exchangers;

the total power of heating and cooling in all carbon dioxide vessels is matched to the total power of all heat engines in the plant system.

6. The method according to any one of claims 1 to 4, a method for energy conversion using carbon dioxide, characterized in that:

the pressure fluctuation of the carbon dioxide before the carbon dioxide enters the heat engine to do work through expansion can be reduced to the minimum in an effort mode;

the carbon dioxide is heated simultaneously during the flow before entering the heat engine;

the carbon dioxide is cooled and liquefied after expanding and doing work in the heat engine, and the low temperature required by cooling and liquefying comes from the cold climate or the utilization of river water or other natural coolants or the low temperature generated when the carbon dioxide expands.

7. The method of any one of claims 1 to 4, a method for energy conversion using carbon dioxide, characterized by comprising one of:

the amplitude of the fluctuations in the operating pressure of the carbon dioxide before entering the heat engine can be reduced by using a combination of nozzles and diffusers to achieve the appropriate amplitude; the total carbon dioxide operating pressure interval can be segmented into different cells, and different heat engines can be used in different, previously separated carbon dioxide operating pressure cells; when the carbon dioxide density before the carbon dioxide enters the heat engine is in the subcritical region, a back pressure turbine with multiple pressure flows is used.

8. The method according to any one of claims 1 to 4, a method for energy conversion using carbon dioxide, characterized in that:

the pressure altitude of the carbon dioxide after expansion in the heat engine is between 1 and 70 bar; the pressure after expansion of the carbon dioxide is highly dependent on the available coolant temperature;

the pressure of the expanded carbon dioxide is generally higher than the pressure of the carbon dioxide in a carbon dioxide vessel in the plant system, where the carbon dioxide is cooled to near the coolant temperature by the cooling process; the cooling process of the carbon dioxide takes place at the end point in time of the carbon dioxide extraction in this container and has switched from heating the carbon dioxide to a carbon dioxide cooling process, i.e. has entered the carbon dioxide cooling process for carbon dioxide filling.

9. Method for energy conversion using carbon dioxide according to any of claims 1-4, characterized in that a carbon dioxide transport system is established comprising carbon dioxide pipes or channels.

10. The method of any one of claims 1 to 4, a method for energy conversion using carbon dioxide,

during refrigeration, the pressure of carbon dioxide in some heat engines after expansion work is reduced as much as possible, so as to be beneficial to refrigeration and produce more electric power;

carbon dioxide gas generated in the refrigeration process can be compressed by a gas compressor driven by electric power and liquefied by low temperature in nature or other available refrigeration modes;

the heat generated during the compression of the carbon dioxide can be used for heating the carbon dioxide to perform energy conversion.

11. A method of energy conversion using carbon dioxide according to any of claims 1 to 4, characterized in that

When surplus electric power is available at night, the pressure of carbon dioxide in some heat engines after expansion to do work can be reduced as much as possible so as to produce more electric power or refrigerate in the daytime;

the surplus electric power at night is used for driving a gas compressor to compress or liquefy carbon dioxide gas after expansion work;

the heat generated in the carbon dioxide gas compression process is used for heating the carbon dioxide in daytime so as to produce more electric energy.

12. A thermal plant system for energy conversion using carbon dioxide as a working medium, characterized in that the thermal plant system is a thermal plant system required for the method according to any of claims 1-11, in order to use the method according to any of claims 1-11.