At the beginning of March 2021, shortly after the Lantern Festival, Hunan Valin Lianyuan Iron & Steel Co. Ltd. (hereinafter referred to as "LY Steel") has already been in intensive production and construction. After a short three-day break during the Spring Festival holiday, the construction team on the expansion line was even more motivated to shorten the schedule and speed up the construction. Recently, the 37,500Nm3/h VPSA oxygen plant (Phase II) of the general energy plant is nearing the end of the installation and will enter the full preliminary commissioning stage. According to the project plan, exclusively equipped for large-scale oxygen-enriched BF coal injection, it will be put into operation within this month to inject oxygen into 6# and 8# blast furnaces of LY Steel after successful oxygen production.

Closely related to it is the 25,000Nm3/h VPSA oxygen generating unit (Phase I) put into operation in early January this year. The two oxygen units will be combined into an extra-large VPSA oxygen plant (62500Nm3/h, 80%) which is going to be one of the largest VPSA oxygen units in China, and help boost LY Steel’s "10 million tons of superior special steel" capacity optimization project.

Oxygen Plant (Phase I) Generated Obvious Benefits and Supply & Demand Contradiction Finally Alleviated

Prior to this, LY Steel had 5 sets of cryogenic air separation oxygen units with a total oxygen capacity of approximately 105,000Nm3/h. Preliminary calculations show the demand for oxygen for 10 million tons of steel production is more than 130,000Nm3/h, so the initial pure oxygen shortage is at least 25,000Nm3/h and will be even larger in the future.

The technical expert group of LY Steel investigated the VPSA oxygen production process in depth and visited VPSA oxygen equipment workshops of other steel enterprises. After comparing the on-site construction level & management standards, and advancement of process indexes from the details, especially after testifying the mature and stable Roots power equipment is the key to ensure the reliable operation of large-capacity VPSA oxygen units, the expert group reached a consensus after discussion that PKU Pioneer’s VPSA oxygen production process has obvious advantages and more advanced indicators. They also highly recognized the core technology, i.e. PKU Pioneer's self-developed patented lithium-based molecular sieve, radial adsorder, automatic control and intelligent centralized adjustment of the system. Achieving unattended operation will better meet the needs for lean and efficient production of LY Steel.

Soon, the two sides reached a smooth cooperation on the construction of the 25,000Nm3/h oxygen production project (Phase I). At that time, LY Steel only relied on the procurement of liquid oxygen to meet the production needs, and the daily amount reached 450 tons during the peak production periods with the price as high as $200/ton, which almost accounts for all the liquid oxygen output of Hunan Province. And when the supply was insufficient, the liquid oxygen even had to be dispatched and purchased from Guangxi, Guangdong and Fujian Province. Under the huge supplying pressure of liquid oxygen of LY Steel, PKU Pioneer actively responded to the customer's demand. Prioritizing the customer's benefits, PKU Pioneer made every effort to promote the construction and the project was finally delivered 10 days in advance. With the 25,000/80 oxygen unit fully reaching the designed capacity, the local liquid oxygen price once dropped to $123/ton and LY Steel successfully achieved the low-cost oxygen supply balance for 10 million tons of steel production capacity, thus completely resolving the long-pending oxygen supply and demand contradiction. In addition，a part of the cryogenic air separation capacity was successfully transferred to the converter, while a strong opportunity was also gained for the air separation unit shutdown for maintenance.

Shorten Construction Period to Expand Production Capacity and 60,000Nm3/h VPSA Oxygen Capacity Surmounted

In 2020, the overall performance of LY Steel was not affected, on the contrary, the annual steel output has seen growth. For the first time, LY Steel achieved the steel output of 10 million tons. Due to the effective prevention and control, the manufacturing wasn’t interrupted throughout the year. By successfully turning crises into opportunities, LY Steel grabbed more orders and created a new milestone in its development. In 2021, aiming at an annual output of 12 million tons of steel, LY Steel will reach another peak.

In order to accelerate optimizing the production capacity of 10 million tons of superior special steel, LY Steel quickly adjusted the deployment to further expand the capacity of VPSA oxygen unit and build another set of VPSA oxygen gas plant with a capacity of 37,500Nm3/h, which will form an extra-large over 60,000 Nm3/h VPSA oxygen unit together with the Phase I project. On December 15, 2020, the construction was officially started and the 37,500/80 VPSA oxygen system will be completed in the Q1 of 2021 to shorten the time gap between the two phases as much as possible and accelerate the commissioning. In response to the production requirements of LY Steel, in spite of the tight schedule and heavy workload of the Phase II, PKU Pioneer’s technical team once again started another race against time and the uncertainties around the Spring Festival holiday.

As the initiating unit of the EPC project, leading the designing units and the construction & installation companies, PKU Pioneer is fully responsible for the overall designing, supply of the complete set of equipment, installation and debugging, on-site construction management, instrument control software programming, system commissioning for oxygen production as well as operation optimization, etc. On the premise of ensuring the oxygen equipment meets the design indicators, PKU Pioneer got down to solve the problem of tight construction work from various aspects and worked as carefully as possible.

In 2020, all parts of China have been in long-time prevention and control. The seemingly routine tasks such as personnel mobility, equipment production, and non-standard transportation have added more difficulties to the project. PKU Pioneer quickly explored and summarized the construction experience when operating under the environment. After the project started, PKU Pioneer and the LY Steel project team jointly formulated a scientific and feasible project implementation plan:

1. Organize workers of different work types to meet daily to adjust the construction volume by day or according to the actual progress. Establish a construction schedule daily reporting mechanism and strictly implement it to ensure the realization of the targets by taking controllable process measures.

2. In terms of component manufacturing, the project manager should assign technical personnel to supervise the production at the manufacturing plant and report the progress on a weekly basis to ensure the equipment components are delivered as scheduled.

3. Establish an impeccable construction command and coordination mechanism prefabricated in different work areas and modules to achieve "no manpower shortage and no construction vacuum zone" on site.

4. Improve and optimize civil construction methods to create a new construction model combined with the VPSA oxygen production process to not only realize simultaneous civil construction and equipment installation but also effectively avoid cross-construction.

PKU Pioneer and LY Steel sincerely collaborated to overcome difficulties. Through meticulous organization and scientific management, the designing, manufacturing and installation nodes were effectively guaranteed to be implemented on time.

According to the comprehensive power consumption of the first-phase VPSA oxygen generator that has been operating for 3 months, the operating cost is less than $0.03/m3 (100% pure oxygen), saving more than 30% of the oxygen usage cost. In addition, by increasing the oxygen enrichment rate of the blast furnace, the output was increased by 500,000 tons, the coke ratio was drastically reduced during the same period, and the coal gas power generation was increased. In sum, the annual comprehensive profits were remarkable. Therefore, the second phase of the VPSA oxygen production project was listed as the "No. 1 Project" of the 12 million tons steel project by LY Steel, which is a crucial part of reaching the annual production target.

In order to speed up deploying and implementing the production, LY Steel has started the corresponding mechanism at the beginning of 2021 to make a good start of production in the first lunar month. For instance, stabilizing the quality of sinter and coke as well as furnace charge structure before iron to ensure the stable and high output of blast furnace, primely organizing the production during the period of power curtailment and load reduction, making a good grasp of material shipment, supply guarantee and inventory reduction, rectifying the energy system and preventing safety accidents, etc. This series of production-centered linked initiatives are the reflection of LY Steel's strategy of emphasizing capacity, considering benefits and strengthening management.

The successful completion of LY Steel's 60,000Nm3/h VPSA oxygen generation project will positively promote the application of ultra-large-capacity VPSA oxygen production technology in iron and steel area in the world. In the future, VPSA oxygen generation technology, serving as an effective means for the blast furnace oxygen enrichment, will attract more and more 10-million-ton steel mills to make it an important component of the energy system, and strongly supplement the steel mill’s oxygen supply with significant advantages such as short construction period, low cost, and fast effects.