Petroleum and petrochemical industry
1.Stainless steel used in petroleum refining equipment.
The stainless steel is used in petroleum refining equipments, whose main material brand is 0Cr13Al ferrite stainless steel; with the different resources of the petroleum, Cr-Ni austenite stainless steel is also used in some highly corrosive parts. The application status of stainless steel in the petroleum refining industry is shown in the following table:
The application of stainless steel in the petroleum refining industry
| Name of the equipment | Material | Application position |
| The distillation tower of the normal pressure crude oil distillation equipments | 0Cr13Al Cr-Ni Austenite stainless steel | 0Cr13Al is used in the tower top and the pallet, under the existence of chloride; stainless steel is used the Cr-Ni austenite |
| Decompression distillation equipment, 350-450℃, 1.3-2KPa | 5CrMo TP316 | The 5CrMo Commonly used，when treating the normal pressure residue oil of naphthenic acid, the TP316 is used in the upper part of the refining tower with the temperature of 250-300℃ |
| The accelerant modification equipment 420-580℃ | TP304 | The high temperature exchanger at the outlet of the reaction tower |
| hydrogenation desulfurization device 200-500℃，3.4-196MPa | TP304 TP321 TP347 TP316L 0Cr13Al | Reaction tower Heating pipe, matching pipe, heat exchanging pipe. The pipes and panels of the tower use stainless steel bead welding The downstream machining equipments for treating wet sulfureted hydrogen. The 0Cr13Al is used in the gasoline and kerosene equipments that contain less H2S |
| The accelerant decomposing equipment, 500℃, normal pressure | 0Cr13Al TP304 | 0Cr13Al or TP304 is used in some parts on the decomposing tower |
| Hydrogen making equipments, absorption and regeneration tower | TP304L | The pipeline that is carbon acid corrosion resistant |
| The grease equipment for solvent extraction: furan aldehyde | TP304 | The heat exchanging pipe which is furan aldehyde corrosion resistant. |
| Waste water treatment equipment | TP304、 TP316L | Equipments on the distillation tower top |
| Sulfur reclaiming equipments (250℃) | 0Cr13Al、 TP304 | The tower and the condenser |
The application of double phase stainless steel in the oil refining industry
| Name of the equipment | Material | The application position and purpose |
| Ordinary decompressor | 00Cr18Ni5Mo3Si2 | Tower top liner, components inside the tower, normal top air cooler, top reducing wetting air cooler, core pipe of top reducing after-cold water cooler, liner of oil water separator. Solve the SCC problem |
| Catalyzing and cracking devices | 00Cr18Ni5Mo3Si2 | Liner of catalyzing and absorbing tower, tower panel, float valve, gasoline reheat machine. Solve the problem of carbon steel’s hydrogen induced cracking, and the uniform corrosion of the austenite stainless steel (1Cr18Ni9Ti) |
| Hydrogenation cracking devices | 0Cr18Ni5Mo3Si2 S31803/S32205 | Air cooler, solve the corrosive pitting of 0Cr13 and 0Cr17, as well as the SCC problem of 18-8 type austenite stainless steel |
| Hydrogenation desulfidation devices | 00Cr18Ni5Mo3Si2 | Heat exchanger and water cooler, solve the SCC problem of the cyanide |
| Waste water treatment equipments | 00Cr18Ni5Mo3Si2 | The heat exchanger and the pot top condenser of the DEA washing device, solve the corrosion pitting of Cr17. And the SCC problem of 0 TP316 |
2.The stainless steel for petrochemical industry
Regarding the waste gas of the petroleum refining factory, natural gas or naphtha as the raw material, through a series of chemistry reaction, it can produce ethylene, propylene, ethyne, etc., a further synthesizing can produce polythene, polystyrene, acetone, butadiene, etc. The machining process after the synthesizing is similar to the chemical industry, and will contact various acidity mediums, the serving environment is very severe, and the variation scale for the medium condition is large, and the materials in use are wide, they involve stainless steel, iron-nickel base anti-corrosion alloy, and nickel base anti-corrosion alloy.
(1) Ethylene production.
TP310S or high carbon TP310S centrifugal casting pipe is used in the furnace tube of the thermal decomposition furnace, which is a choice made according to the high temperature and high creep rupture strength. Incolog800 alloy is adopted in the pipeline. Under the low temperature condition, low temperature steel should be used, and the TP304 is used only under the condition of -100–175℃.
(1) Ethyne
In the production of ethyne, as the decomposing temperature is above 1100℃, the alloy brand in use is higher than the one used in producing ethylene.
(3) Other treating process
Other treating processes including oxidation, hydration, dehydrogenation, dehydration, alkylation, anisotropisation ect. The equipments will contact the relevant acidity mediums, and the materials in use are mainly TP316L and 0 TP316L，Inconel600、Incoloy800，No.20 alloy and Hastelloy B、C、D, etc. The process conditions of work are shown in the table below. In the process of petroleum chemical engineering, sulfuric acid, hydrofluoric acid, phosphoric acid, hydrochloric acid and other corrosive mediums need to be used in some processes. According to the acid concentration, different corrosion resistant materials are used with the different temperature.
The working condition of the processes in petrochemical industry
| Name of the technique process | Temperature, ℃ | Pressure, MPa |
| Oxidation | 150-450 | ≥1.9 |
| Hydration | 10-300 | 0.68-6.9 |
| Dehydrogenation | 350-700 | 0-0.15 |
| Dehydration , alkylation | 250-275 | 1.4-6.2 |
| Anisotropisation | 370-540 | 1.4-1.5 |
| Hydrogen mixture, halogenations | 30-500 | 0-0.34 |
| Azotizing | 30-500 | 0-0.19 |
| Superposition | 160-300 | 0-294 |
Sulfuric acid The variation scale for the concentration of the sulfuric acid in the petrochemical industry is very large, and the temperature can be up to around 100℃, the sulfuric acid concentration and temperature condition during some technique processes are shown in the following table. You can choose according to the material application principle of sulfuric acid industry in the mechanical industry.
The H2SO4 used in petrochemical industry
| Technique process | Concentration of H2SO4 | Temperature, ℃ |
| Produce ethanol or IPA with ethylene water | 45%-98% | 0-80 |
| Produce aether with dehydration | 78%+H3PO4+HCI | 128 |
Phosphoric acid Used to make alcohol, synthesized detergent and interfacial active agent; for the various concentration H3PO4 with the concentration lower than 30% and a boiling temperature lower than 60℃, use TP304, and for the high temperature and high concentration H3PO4, use 0 TP316L.
Hydrochloric acid In petrochemical industry, hydrochloric acid is used in the production including the liquid-phase oxidation of ethylene to aldehyde, acetone production, anisotropisation, the halogenation technique for producing chlorinated ethenoid resin, under such environment, the common stainless steel is not corrosion resistant. Ni-Mo and Ni-Cu alloy are often used or nonmetallic material liner is used. And only for the diluted hydrochloric acid that contains air, use 0Cr17Ni12Mo steel.
The double phase stainless steel has been successfully used in petrochemical industry, shown in the following table:
The typical application of double phase stainless steel in petrochemical industry
| Name of the equipment | MaterialMaterial | Application position |
| PVC production equipment | 00Cr25Ni6.5Mo3.5CuN | Stripping tower and heat exchanger, substituting the TP316 and 2205 |
| Polythene production equipment | 00Cr25Ni7Mo3.5wCuN (Zeron 100) 00Cr18Ni5Mo3Si2 | Oxychlorination reactor, HCL cooler, chloroethylene tower oxychlorination reactor, substituting TP321, SCC chloroethylene reboiler is not seen for 5 years. |
| Formaldehyde synthesizing reactor | 00Cr18Ni5Mo3Si2 00Cr22Ni5Mo3N | Mini size reactor Large size reactor Pipeline system of the heat exchanger for material/outflow stuff Medium pressure inner distillation top condenser |
| Reactor for Carbonyl synthetic alcohols | 00Cr22Ni5Mo3N | With expected life span of 15 year, Substituting the original reactor made of austenite stainless steel (subject to heat fatigue) |
| Acetic acid production equipment | 2507 (00Cr25Ni7Mo4N) | Resistant to the corrosion of MnCl2，MnAC (manganese acetate) accelerant acetic acid |
| TPA terephthalic acid production equipments | Zeron100 2507 | Equipment of the first cooler for reproducing accelerant |