With steel company's producing capacity increasing, how to select suitable oxygen technology

The recent situation of steel development in China can be generalized into three aspects. Firstly, constant global economic recovery will increase Chinese export business, especially under the policy of “Belt and Road”, which encouraged steel company’s export business. Though Chinese infrastructure and estate investment go down,domesticmacro economyruns well, and steel company'sproduction-saleincreases obviously. Secondly, by banning substandard steel and eliminating backward capacity, steel company achieved obvious effects on deducing capacity. Some local policy and environment rules restrict the producing capacity, for which market supply and demand are effectively adjusted. Even the price ofsteelmaterial is variable, it will be keptina high level,meanwhilethe earning ability and standard of steel company will also be keptina high level. Thirdly, technological progress and industrial upgrading insteelindustry will further release quality capacity, but the strict control of newly increased capacity promotes more investment onenvironmentand technological progress. It will become the development direction of the steel industry to improve the industrial structure, improve product competitiveness and added value, and improve the production capacity through technological progress.

In all, the present situation of steel industry develops well, but institutes and experts in China hold different opinions on steel's futures for this industry is under many factors, such as raw material price, policy, environment, international trade barrier, down-stream product,macro economy. No matter what the situation is, many companies want to grasp this chance to control the capacity, equivalent substitution and close down the outdated production, so quite a lot companies focus their attention on the technology that could enlarge the production capacity, among which increasing oxygen enrichment rate is an efficient way. In 2017, many steelcompanyenlarged their oxygen capacity and invest to build large oxygen plants. One of the efficient and popular oxygen generating methods is VPSA oxygen technology.

According to Beijing Peking University Pioneer Technology Company (Professional supplier of VPSA equipment in China), VPSA oxygen technology separates oxygen from nitrogen byadsorbent, and there is no by-product except oxygen, and theoxygen enrichedwill be used beforeblower. Compared withcryogenicmethod, VPSA has many advantages, such as oxygen production cost is lower, plant construction period is shorter, flexible turn down, easy operation, which meets the needs of enlarging capacity.

Firstly, the operation cost of VPSA is low. The power consumption rate is 0.32kwh to 0.35kwh producing one cubic pure oxygen. If the power cost 0.5rmb perkwh, the operation cost of VPSA is 0.15rmb. Considering the depreciation cost, labor cost and maintenance cost, the cost of producing one cubic oxygen is under 0.3rmb.

Secondly, the construction period is short. From civil construction to installation, and then to test run, it cost 6 months to get oxygen. In recent years, steel company prefers such short construction period, which can bring benefit quickly. The earning will be very sizable if the oxygen plant startsto ,based on the price of steel now.

Thirdly, flexible turn down. VPSA oxygen plant can enlarge the steel plant's oxygen capacity, the redundant oxygen can be fed tosteel makingsystem if oxygen is enough forblastfurnace. Additionally, if the steel situation goes down in future, VPSA plant could adjust its turn down ration to save more cost.

Fourthly, easy operation. VPSA plant works underautomaticcontrol system, which only needs 6-8 workers, also professionalism is not required. So it is easy to add them into human resource system and don’t cause trouble tocompany.

The following data are collected from a VPSA oxygen plant in a steel company as a reference.

There are three blast furnaces in this steel company, 3200m3, 2500m3and1080m3. The oxygen enrichment rate goes up by 1%, the capacity goes up 4.76% by theory, 3-4% in reality.Alsothe coal is also increased by 12-13kg/t, and coke ration decreased by 0.5%. The oxygen enrichment rate goes by 1%, the heat value increases by 3.4%, andoff gasofblast furnace is easier for combustion. Upon the current situation of this company, it is to increase the oxygen enrichment ratio to 4.4% from 3.5%, relatively the oxygen flow to 49000Nm3/h from 39000Nm3/h, namely the pure oxygen increases by 10000Nm3/h.

If iron producing ratio is increased to 3%, the total iron capacity is increased by 475t/d. Considering 350 working days a year and 700rmb benefit added per ton iron, the total benefit added will be 116.42 millionrmbper year.

At the same time,costadded per year is around 20 million, so the net benefit will be 96 millionrmbper year.

Compared with the cryogenic plant ofsamecapacity, considering the construction periods difference and oxygen producing cost difference (take 0.1rmb/m3 cost asexample), what VPSA brings to the company is 4 months shorter period and 32 million one-timebenefit. That is 8.4 millionrmbis saved per year.

Above all, oxygen enriched coal spray is one of the efficientwayfor energy saving, coke saving and capacity enlarging. enriched oxygen can also promote the use of blast furnace gas, and rich oxygen combustion technology can make up for the shortcomings oflowcalorific value of blast furnace gas and increase efficiency. If the steel company take oxygen enrichment as a key point, and equipment company with VPSA oxygen system, byoxygen enrichedcoal spray, the iron production capacity will be enlarged and sizeable benefits will be earned.