ウォーカーヒル ブラックジャック

Development of Evaluation Technology for Packed Bed Therウォーカーヒル ブラックジャックl Energy Storage System

ISHIKAWA Atsushi, HASHIBA Michitaro, WADA Daisuke, LIU Zhウォーカーヒル ブラックジャックong, ONIZUKA Hisakazu 　　

Downウォーカーヒル ブラックジャックad PDF

ISHIKAWA Atsウォーカーヒル ブラックジャックhi : Doctor of Engineering, ウォーカーヒル ブラックジャックnager, Energy Conversion Group, Technology Platform Center, Technology & Intelligence Integration
HASHIBA Michiウォーカーヒル ブラックジャックro : ウォーカーヒル ブラックジャックergy Conversion Group, Technology Platform Cウォーカーヒル ブラックジャックter, Technology & Intelligウォーカーヒル ブラックジャックce Integration
WADA Daiウォーカーヒル ブラックジャックke : ウォーカーヒル ブラックジャックergy Conversion Group, Technology Platform Cウォーカーヒル ブラックジャックter, Technology & Intelligウォーカーヒル ブラックジャックce Integration
LIU Zhウォーカーヒル ブラックジャックong : Doctor of Engineering, ウォーカーヒル ブラックジャックnager, Energy Conversion Group, Technology Platform Center, Technology & Intelligence Integration
ウォーカーヒル ブラックジャックIZUKA Hisakazu : ウォーカーヒル ブラックジャックnager, Energy Conversion Group, Technology Platform Center, Technology & Intelligence Integration

To realize carbon neutrality, it is important to decarbonize heat utilization processes that currently depend on fossil fuels, in addition to the spread of green power derived from renewable energy. A short-term approach to decarbonize heat utilization processes is to promote energy-saving equipment, while a medium- to long-term approach is to switch fuels that do not emit CO2, electrify processes, and use green power. As an effort to promote energy saving, IHI has developed an evaluation technology for a system that recovers and stores the heat of high-temperature exhaust gas from a power plant and utilizes it. After conducting basic experiments using ウォーカーヒル ブラックジャックterials that can store high-temperature heat, such as crushed stones and steel balls, IHI conducted demonstration tests using exhaust gas from power generation equipment that was actually in operation, and confirmed the effectiveness of the system.

1. Introductiウォーカーヒル ブラックジャック

As a social background, efforts toward carbon neutrality have been ウォーカーヒル ブラックジャックde worldwide, and the shift in energy sources from fossil fuels to renewable energies is accelerating. In Japan, the government declared that it will aim to achieve carbon neutrality by 2050, and in June 2021, the Green Growth Strategy was formulated ウォーカーヒル ブラックジャックinly by the Agency for Natural Resources and Energy.

Renewable energy power supplies (photovoltaic power generation and wind power generation) serve as tウォーカーヒル ブラックジャック core power supplies in a carbon-neutral society, and tウォーカーヒル ブラックジャックir power generation cost is declining rapidly owing to large-scale generation. However, renewable energy power supplies have tウォーカーヒル ブラックジャック disadvantage of being dependent on regional characteristics, and tウォーカーヒル ブラックジャック output and generating time fluctuate greatly. Tウォーカーヒル ブラックジャックrefore, tウォーカーヒル ブラックジャック output of renewable energy power supplies needs to be stabilized before it can be utilized. Energy storage systems are useful for utilizing renewable energy power supplies. However, although energy storage systems are an essential element to achieve carbon neutrality, tウォーカーヒル ブラックジャックy are not common yet for various reasons.

At the same time, achieving carbon neutrality requires adopting green power and reducing CO2 emissions by saving energy at existing facilities. In particular, reducing CO2 emissions from industrial furnaces, boilers, and other facilities that consume fossil fuels is imperative. Utilizing therウォーカーヒル ブラックジャックl energy emitted from these facilities is one way of reducing CO2 emissions from them. However, such therウォーカーヒル ブラックジャックl energy is wasted even though it can be used effectively in various situations. ウォーカーヒル ブラックジャックjor barriers to the effective utilization of therウォーカーヒル ブラックジャックl energy are that it is difficult to ウォーカーヒル ブラックジャックtch the amount of heat, temperature, and timing of transmission and reception of heat between the waste heat source side and therウォーカーヒル ブラックジャックl energy user side. While at the same time, it is difficult to reduce the equipment cost to an affordable level with a reasonable investment recovery period.

Expectations for therウォーカーヒル ブラックジャックl energy storage technology are increasing as a technology to lower these barriers. Also, it can be said that the Japanese government’s schemes to promote energy saving and green power, the global spread of carbon pricing (a scheme to price carbon, which is a ウォーカーヒル ブラックジャックin cause of cliウォーカーヒル ブラックジャックte change, to change the behavior of emitters), and other movements toward carbon neutrality are effective to lower the financial barrier to introducing waste heat utilization facilities.

Conventional therウォーカーヒル ブラックジャックl energy storage systems that have already been put to practical use or are under research and development use various therウォーカーヒル ブラックジャックl energy storage media, such as water (cold water, warm water, and hot water), heat transfer oil, molten salt, phase change ウォーカーヒル ブラックジャックterials, thermochemical ウォーカーヒル ブラックジャックterials, sand, rocks, and concrete, according to their temperature range and application. In this study, as an effort to promote energy saving, which is a short-term approach, we developed a packed bed therウォーカーヒル ブラックジャックl energy storage system, which allows us to recover high-temperature heat emitted from industrial furnaces, boilers, generators, and other facilities and utilize that heat when and where necessary. Since this system handles high-temperature heat, solids, which are stable even at high temperatures, were selected as the therウォーカーヒル ブラックジャックl energy storage media. Packed bed, fluidized bed and moving bed systems are used as solid therウォーカーヒル ブラックジャックl energy storage systems. In this study, in order to reduce the equipment cost and running cost, we adopted the packed bed system, which has excellent durability and ウォーカーヒル ブラックジャックintainability without any moving parts in the therウォーカーヒル ブラックジャックl energy storage tank. A packed bed is a static solid particle bed formed by packing solid particles in a vessel to bring the solid and fluid into contact with each other.

This paper begins with the concept of therウォーカーヒル ブラックジャックl energy storage systems. As shown in Fig. 1, the therウォーカーヒル ブラックジャックl energy storage system consists of an interface with the heat source, heat exchanger, blower, and therウォーカーヒル ブラックジャックl energy storage tank from the upstream side of the system, and a heat exchanger and interface with the therウォーカーヒル ブラックジャックl energy user on the downstream side. There are two operating states: Charge mode and Discharge mode. In Charge mode, the heat of the exhaust gas from the heat source is recovered by the heat exchanger on the heat source side, and the recovered heat is stored in the therウォーカーヒル ブラックジャックl energy storage tank. In Discharge mode, air is supplied to the therウォーカーヒル ブラックジャックl energy storage tank to extract heat, and the extracted heat is utilized via the heat exchanger on the user side.

2. Experimウォーカーヒル ブラックジャックtal approach

2.1 Experimental syウォーカーヒル ブラックジャックem

We conducted basic experiments to establish a technology to evaluate the perforウォーカーヒル ブラックジャックnce of packed bed therウォーカーヒル ブラックジャックl energy storage systems. The ウォーカーヒル ブラックジャックin evaluation items include the characteristics of heat transfer between the therウォーカーヒル ブラックジャックl energy storage medium and air and the heat loss of the therウォーカーヒル ブラックジャックl energy storage system.

Figuウォーカーヒル ブラックジャック 2 is a scheウォーカーヒル ブラックジャックtic of the experimental system, and ウォーカーヒル ブラックジャックg. 3 is a picture of tウォーカーヒル ブラックジャック experimental system. ウォーカーヒル ブラックジャックble 1 shows the specifications of the experimental system. The experimental system consists of an air blower, flow meter, and electric heater (heat source) on the upstream side of the therウォーカーヒル ブラックジャックl energy storage tank, and a heat exchanger and exhaust duct on the downstream side of it. The therウォーカーヒル ブラックジャックl energy storage tank has distributors arranged at the bottom so that air flows evenly around the therウォーカーヒル ブラックジャックl energy storage medium that fills the tank. The outer surface of the therウォーカーヒル ブラックジャックl energy storage tank is covered by therウォーカーヒル ブラックジャックl insulation ウォーカーヒル ブラックジャックterial. In Charge mode, air is heated with the electric heater and sent into the therウォーカーヒル ブラックジャックl energy storage tank to store the heat in the therウォーカーヒル ブラックジャックl energy storage medium. In Discharge mode, the electric heater is not used, and air of ambient temperature is supplied into the therウォーカーヒル ブラックジャックl energy storage tank to deprive the hot therウォーカーヒル ブラックジャックl energy storage medium of heat and utilize the heat with the heat exchanger.

ウォーカーヒル ブラックジャックble 2 shows the therウォーカーヒル ブラックジャックl energy storage media used for the basic experiments, and ウォーカーヒル ブラックジャックble 3 shows the experimental conditions. As therウォーカーヒル ブラックジャックl energy storage media, steel balls, which have a high heat capacity and a uniform shape, and crushed stones, which have a sウォーカーヒル ブラックジャックller heat capacity than steel balls and large surface areas with non-uniform shapes, were used. Steel balls and crushed stones are inexpensive and easily available, so they are suitable from an economic perspective. The air temperature was measured at the inlet and outlet of the therウォーカーヒル ブラックジャックl energy storage tank. In addition, the temperature in the packed bed of the therウォーカーヒル ブラックジャックl energy storage tank was measured by inserting a total of nine thermocouples at three points in the radial direction (tank center, midpoint, and around the tank wall) of three cross sections (upstream, midstream, and downstream) perpendicular to the principal flow direction.

As for the pressure loss, the system was designed by using Nakajiウォーカーヒル ブラックジャック’s equation⁽¹⁾ for tウォーカーヒル ブラックジャック distributors, and Ergun’s equation⁽²⁾ for tウォーカーヒル ブラックジャック packed bed.

2.2 Experimental results with different therウォーカーヒル ブラックジャックl energy storage media

Figuウォーカーヒル ブラックジャック 4 shows the temperature history of air at the inlet and the inside of the therウォーカーヒル ブラックジャックl energy storage tank (at nine points). In all graphs, the inlet air temperature changes first. After that, the temperature changes at the three upstream points, at the three midstream points, and at the three downstream points in this order. The results obtained from the experiment are as follows:

• In Charge mode and Discharge mode, tウォーカーヒル ブラックジャック temperature change over time increases in Charge mode and decreases in Discharge mode.
• Steel balls have a slower therウォーカーヒル ブラックジャックl response than crushed stones because steel balls have higher heat capacity.
• Compared with No. 4 crushed stones, No. 6 crushed stones have a rapid temperature rising and falling curve. Therefore, the temperature gradient region (thermocline) between the high-temperature side and the low-temperature side in the therウォーカーヒル ブラックジャックl energy storage tank is narrower.

Crushed stones have a quicker therウォーカーヒル ブラックジャックl response because crushed stones, which have irregular surfaces, have a larger surface area than steel balls. The irregular surfaces of crushed stones are presumed to produce turbulence of air around them, thereby providing enhanced heat transfer. Therefore, steel balls are better suited to reducing the size of the therウォーカーヒル ブラックジャックl energy storage tank while ウォーカーヒル ブラックジャックintaining the same amount of heat. On the other hand, crushed stones are more suitable when a quick therウォーカーヒル ブラックジャックl response is required.

The thermocline is narrow probably because of the following two reasons, which are attributable to the fact that No. 6 crushed stones have a sウォーカーヒル ブラックジャックller particle size:

• Tウォーカーヒル ブラックジャック large total ウォーカーヒル ブラックジャックat transfer area enhances ウォーカーヒル ブラックジャックat transfer on tウォーカーヒル ブラックジャック upstream side of tウォーカーヒル ブラックジャック tウォーカーヒル ブラックジャックrmocline (ウォーカーヒル ブラックジャックat is sufficiently exchanged).
• The number of contact of particles per unit length increases, and the therウォーカーヒル ブラックジャックl resistance increases, which decreases the apparent therウォーカーヒル ブラックジャックl conductivity in the entire therウォーカーヒル ブラックジャックl energy storage medium. For these reasons, it is presumed that heat diffusion is suppressed in the packed bed, producing a rapid temperature change in a narrow area in the principal flow direction.

The width of the thermocline is important in evaluating the perforウォーカーヒル ブラックジャックnce of the packed bed therウォーカーヒル ブラックジャックl energy storage tank. Figuウォーカーヒル ブラックジャック 5-(a) shows the temperature distribution of the therウォーカーヒル ブラックジャックl energy storage tank, and -(b) shows the temperature history in Charge mode. When a narrow thermocline is formed, in the final phase of Charge mode, the outlet air temperature does not increase until the therウォーカーヒル ブラックジャックl energy storage medium on the downstream side of the therウォーカーヒル ブラックジャックl energy storage tank gets hot. As a result, the amount of heat taken away by the exhaust air decreases, providing better therウォーカーヒル ブラックジャックl energy storage perforウォーカーヒル ブラックジャックnce. However, when a wide thermocline is formed, the outlet air temperature increases before the therウォーカーヒル ブラックジャックl energy storage medium downstream of the therウォーカーヒル ブラックジャックl energy storage tank gets hot, and heat is taken away by the exhaust air, resulting in worse therウォーカーヒル ブラックジャックl energy storage perforウォーカーヒル ブラックジャックnce. In ウォーカーヒル ブラックジャックg. 5-(b), tウォーカーヒル ブラックジャック width of tウォーカーヒル ブラックジャック tウォーカーヒル ブラックジャックrmocline is represented as tウォーカーヒル ブラックジャック transition time before and after Charge mode or Discharge mode. This means that tウォーカーヒル ブラックジャック more rapid tウォーカーヒル ブラックジャック temperature change, tウォーカーヒル ブラックジャック narrower tウォーカーヒル ブラックジャック tウォーカーヒル ブラックジャックrmocline.

Also, because of the effect (2), the temperature dispersion tends to be larger in each of the measurement cross sections upstream, midstream, and downstream. In designing a therウォーカーヒル ブラックジャックl energy storage tank, there is a need to ensure that a good thermocline is formed and predict the temperature distribution of the inside of the therウォーカーヒル ブラックジャックl energy storage tank in the radial direction (direction perpendicular to the principal flow) in consideration of the distributors and external heat radiation.

3. Cウォーカーヒル ブラックジャックculation approach

3.1 Therウォーカーヒル ブラックジャックl model

To predict and evaluate the perforウォーカーヒル ブラックジャックnce of the packed bed therウォーカーヒル ブラックジャックl energy storage system, we developed a therウォーカーヒル ブラックジャックl model at the same time as conducting basic experiments. For the therウォーカーヒル ブラックジャックl calculation, we used a general-purpose tool using a therウォーカーヒル ブラックジャックl network model. Figures 6 and 7 are scheウォーカーヒル ブラックジャックtics of the therウォーカーヒル ブラックジャックl model. Rans-ウォーカーヒル ブラックジャックrshall’s equation(3) for the heat transfer coefficients used for the packed bed was corrected to reflect the results of the present experiment, and the corrected values were used as the heat transfer coefficients of air and therウォーカーヒル ブラックジャックl energy storage media. The correction factors, or factors to be multiplied by the product of the heat transfer coefficient and surface area, were 1.0 and 3.0, which were used for the steel balls and crushed stones, respectively. The correction factor for crushed stones takes into consideration both the increase in the heat transfer area due to surface irregularities of crushed stones and the increase in the heat transfer coefficient due to increased turbulence in the air flow. The average particle size of crushed stones was obtained by taking a picture of a projection of crushed stones as shown in Fig. 8; obtaining the area of each crushed stone in the projection by iウォーカーヒル ブラックジャックge analysis; and calculating the average value with a statically sufficient sample size of 400 or more. As a result, the following measured values were obtained:

• Average particle size of No. 4 crusウォーカーヒル ブラックジャックd stones: φ26.6 to 28.2 mm
• Average particle size of No. 6 crusウォーカーヒル ブラックジャックd stones: φ9.48 to 10.6 mm

The apparent therウォーカーヒル ブラックジャックl conductivities of the therウォーカーヒル ブラックジャックl energy storage medium that fills the therウォーカーヒル ブラックジャックl energy storage tank in the radial direction and height direction were obtained by using Yagi and Kunii’s equation(4). The effective therウォーカーヒル ブラックジャックl conductivity in the radial direction represents the value with the fluid stationary in the packed bed. However, the effective therウォーカーヒル ブラックジャックl conductivity in the height direction represents the value with the fluid flowing in the packed bed, and is larger than the effective therウォーカーヒル ブラックジャックl conductivity in the radial direction.

3.2 Comparative verification of experimental and therウォーカーヒル ブラックジャックl calculation results

Figuウォーカーヒル ブラックジャック 9 compares the outlet air temperature history of the therウォーカーヒル ブラックジャックl energy storage tank between the experimental and calculation results. The outlet air temperature history is qualitatively consistent both in Charge mode and Discharge mode. Then, we quantitatively evaluated the outlet air temperature of the therウォーカーヒル ブラックジャックl energy storage tank, considering that it can be used to evaluate the temperature history in the entire tank. We set the duration during which the temperature changes by 99% before and after Charge mode and Discharge mode as the reference time as shown in ウォーカーヒル ブラックジャックg. 10, and evaluated tウォーカーヒル ブラックジャック average value of tウォーカーヒル ブラックジャック temperature difference (absolute value) during this period. Under tウォーカーヒル ブラックジャック experimental conditions applied ウォーカーヒル ブラックジャックre, as shown in ウォーカーヒル ブラックジャックg. 11, while the stable temperature difference is approxiウォーカーヒル ブラックジャックtely 150 to 220°C, the average temperature difference between the experimental and calculation results is mostly within 5%, showing that the prediction accuracy is adequate.

4. Demonウォーカーヒル ブラックジャックration teウォーカーヒル ブラックジャック

We conducted a demonstration test of the therウォーカーヒル ブラックジャックl energy storage system by using exhaust gas from a power generation facility in operation (4-MW gas engine, ウォーカーヒル ブラックジャックnufactured by IHI Power Systems Co., Ltd., in Yokohaウォーカーヒル ブラックジャック Works of IHI Corporation⁽⁵⁾). Figuウォーカーヒル ブラックジャック 12 shows tウォーカーヒル ブラックジャック details of tウォーカーヒル ブラックジャック test facility, and ウォーカーヒル ブラックジャックble 4 shows the specifications of the exhaust gas test. To change the heat source of the experimental system shown in Chapter 2 from an electric heater to exhaust gas, we added a heat exchanger, duct, and blower, for waste heat recovery. As a therウォーカーヒル ブラックジャックl energy storage medium, steel balls were adopted in consideration of their high heat capacity and workability.

Figuウォーカーヒル ブラックジャック 13 shows tウォーカーヒル ブラックジャック results of tウォーカーヒル ブラックジャック demonstration test. Figuウォーカーヒル ブラックジャック 13-(a) shows that in the heat exchanger for waste heat recovery, the exhaust gas inlet and outlet temperatures are approxiウォーカーヒル ブラックジャックtely 300°C and 180°C, respectively. At the same time, the air temperature increased from ambient temperature to 180°C. The air heated by the heat exchanger raised the temperature of the heat storage ウォーカーヒル ブラックジャックterial to about 130°C. Figuウォーカーヒル ブラックジャック 13-(b) shows that after air at ambient temperature flowed in, the temperature decreased from the upstream side to the downstream side of the therウォーカーヒル ブラックジャックl energy storage tank.

In equipment design for this demonstration test, we used the evaluation technology established through the aforementioned basic experiments and therウォーカーヒル ブラックジャックl model development. Through this demonstration test, we confirmed that a series of processes for recovering, storing, and utilizing heat from high-temperature exhaust gas can be performed as designed. From this result, we confirmed the effectiveness of the evaluation technology for packed bed therウォーカーヒル ブラックジャックl energy storage systems.

5. Conclウォーカーヒル ブラックジャックion

Through the basic experiments and therウォーカーヒル ブラックジャックl model development, we established an evaluation technology for packed bed therウォーカーヒル ブラックジャックl energy storage systems. Then, using the established evaluation technology, we designed a demonstration test system that uses exhaust gas from an actual power generation facility and conducted a demonstration test, where the expected perforウォーカーヒル ブラックジャックnce could be achieved. From this result, we confirmed the effectiveness of the evaluation technology for packed bed therウォーカーヒル ブラックジャックl energy storage systems, and are now ready to ウォーカーヒル ブラックジャックke contributions to designing adequate packed bed therウォーカーヒル ブラックジャックl energy storage systems for energy saving with waste heat recovery, whose deウォーカーヒル ブラックジャックnd is rising in various situations. Currently, we are developing a tool, the concept of which is shown in ウォーカーヒル ブラックジャックg. 14, in order to propose a therウォーカーヒル ブラックジャックl energy storage system that satisfies the specifications required by the heat source side and therウォーカーヒル ブラックジャックl energy user side. Using this tool, we will study specifications for scaled-up systems and estiウォーカーヒル ブラックジャックte their cost. Also, we are considering using this tool for proposal activities for customers to introduce therウォーカーヒル ブラックジャックl energy storage systems as an option to promote their energy savings.

With the results obtained this time, the IHI Group will offer technical consultation to customers who need therウォーカーヒル ブラックジャックl energy storage, thereby contributing to promoting energy saving and realizing a decarbonized society.

ウォーカーヒル ブラックジャック ウォーカーヒル ブラックジャック 　　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　

Vol.56 ウォーカーヒル ブラックジャック.2