Articles
Optimization of Operation for Multiple Oxygen Burners in Industrial Furnaces
Industrial furnaces often operate multiple burners, where conventional tuning remains suboptimal and manual search becomes infeasible as the combinatorial space explodes. We built a data-driven framework based on Bayesian optimization to efficiently select operating conditions. First, computational fluid dynamics for a two-burner test furnace identified NOx reducing settings with few trials. Next, we validated on a four-burner furnace. Despite the vastly larger search space, Bayesian optimization reached promising conditions rapidly. These results show that Bayesian optimization is effective for optimizing complex burner operations and has strong practical applicability.
(Full pages PDF:1152KB)
Application of Turbo Machinery Using Mixed Cooling Gas
Neon is expected to see growing demand for semiconductor-related applications; however, concerns over supply stability have emerged due to changes in the global situation, making domestic production an important challenge. In response, our company is planning to produce neon using crude neon obtained from the large air separation unit at the Kimitsu Sanso Center.
The cooling system of the neon purification unit employs the turbo compressor and expansion turbine of NeoKelvin®-Turbo, which has been commercialized using our refrigeration-cycle and turbomachinery technologies. To prevent liquefaction of the refrigerant and to optimize the turbomachinery design, the cooling system uses a mixed refrigerant consisting of neon gas and helium gas. In this paper, we report on an overview of the cooling system, the mixing ratio of the refrigerant gas, and the design and evaluation of the turbomachinery.
(Full pages PDF:941KB)
New Technologies & Systems
Utilization of digital technology for PSA process development
We developed a PSA process simulation model to improve the efficiency of PSA process development. The framework comprises an adsorption column model that solves mass- and energy-balance equations within the column, together with valve models. The model was applied to a two-column PSA and a four-column VPSA for hydrogen purification from ammonia decomposition gas. The simulated in-column pressure and temperature profiles for the two-column PSA, as well as the impurity concentrations in the product gas for both processes, showed close agreement with experimental data. Deploying the model on a computational platform enables pre-experimental screening, reducing rework and shortening development lead times while enhancing the efficiency and sophistication of PSA process development.
(Full pages PDF:606KB)
Development of Ammonia-oxyfuel combustion technology for industrial furnaces
This report introduces the development of ammonia-oxyfuel combustion technology aimed at utilizing ammonia for heat in industrial furnaces to achieve a carbon-neutral society. Although ammonia faces challenges such as low burning velocity, weak radiant radiative heat transfer, and high NOx emissions, we achieved stable combustion by combining oxy-fuel combustion with staged combustion, reaching a heat transfer efficiency of 55% or more and NOx emission concentrations of 360 ppm or less. Furthermore, we conducted the world's first demonstration test in an actual production glass melting furnace and confirmed the feasibility of its application to industrial furnaces. In the future, we aim to scale up the technology and expand its application to other industrial furnaces.
(Full pages PDF:589KB)
Supply technology for high-purity solid-state precursor MoO2Cl2 for semiconductors
Regarding MoO₂Cl₂, which is expected to be a next-generation material, we developed core technologies for material quality control and supply, and obtained the following results:
- It was confirmed that by applying containers with corrosion-resistant inner surface treatments, it is possible to suppress the contamination of metal impurities derived from the container even after repeated use. This led to the establishment of a corrosion countermeasure technology for MoO₂Cl₂.
- Applying a proprietary purification process reduced the metal impurity concentrations in the gas phase to less than 100 wt.ppb, which is our control criterion. This led to the realization of a high-purity MoO₂Cl₂ material suitable for semiconductor process applications.
- A stable MoO₂Cl₂ gas supply technology was established using a pressure feedback control system we adopted.
- Temperature uniformity within the container was improved by optimizing the internal structure of the container, indicating the potential for improving material utilization efficiency.
In the future, we will proceed with reliability evaluations toward the advancement of mass production facilities and supply unit functionality, aiming to expand their applications to next-generation semiconductor processes.
(Full pages PDF:733KB)
Development of a highly sensitive analytical method for detecting impurities in CO2 using gas separation membrane
In recent years, the demand for high-purity gases has increased with the miniaturization of semiconductor devices, and CO2 is one representative example. To meet the stringent quality assurance requirements by users, our company has been conducting gas concentration analysis using cryogenic trapping with liquid nitrogen. However, this method has technical limitations, such as the inability to concentrate target components when the main component has a high boiling point.
In this study, we developed a new concentration analysis technique that exploits differences in the permeation rates of individual molecules through a gas separation membrane. We invenstigated the feasibility of concentration and the material balance for C3H8 in CO2. As a result, it was found that concentration analysis can be performed using a separation membrane.
(Full pages PDF:492KB)
Development of Impurity Removal Technology for Crude Neon Gas
Neon is used as a diluent gas for excimer lasers in the semiconductor manufacturing process, and global supply concerns have become evident following the Russian invasion into Ukraine. In response, the Japanese government is strengthening the domestic production system from the perspective of economic security, and our company has decided to install a neon purification system by utilizing a government grant.
This report provides an overview of the neon purification process developed by our company and describes the design of a vacuum pressure swing adsorption unit that employs a room-temperature adsorption and vacuum regeneration method to remove nitrogen, an impurity. The newly developed process enables neon purification with lower power consumption and a more compact cold box compared to conventional methods.
(Full pages PDF:345KB)
Cryogenic Air Separation Unit (ASU) Pilot Plant
Nippon Sanso Corp. designs the main equipment of cryogenic air separation units (ASUs)—packed columns and condensers—using an in‑house design program based on rate-based theory. To accommodate recent diversification of ASU processes and improvements in packing and condenser performance, we constructed a cryogenic pilot ASU at the Tsukuba laboratory in 2021 that can obtain equipment performance data under a wide range of operating conditions. The facility consists of packed‑column and condenser test sections installed in a vacuum-insulated cold box, and reboilers, a condenser and other auxiliary equipment installed in a perlite-insulated cold box. It enables packed‑column tests, condenser tests, and mixing‑column tests, and can reproduce arbitrary compositions, pressures, and vapor/liquid load. In this paper, Ar–O₂ packed‑column distillation tests are presented as an example. With increasing vapor load, the separation performance improved above a pressure drop of 400 Pa/m and reached a maximum at the loading point, but deteriorated sharply at higher loads. Using this facility, we will evaluate packing performance, develop new-type condensers, and thereby reduce ASU capital and power consumption while meeting increasingly diverse product requirements.
(Full pages PDF:468KB)