NH1949

NH1949 Anti-coking New Material

Innovative New Materials

Extend Decoking Cycle

Extend Tube Life

Cut Costs, Boost Efficiency

New Materials

NH1949 Description

NH1949 Anti-coking New Material

Since 2012 NPA has developed a new generation of ethylene-cracking tubes. Addition of Al forms a stable Al₂O₃ scale for outstanding oxidation, carburization and coking resistance; W and rare metals provide solid-solution and grain-boundary strengthening, maintaining high mechanical properties above 1100 ℃.

NH1949 anti-coking new material is the first high-temperature alloy material in China that is completely resistant to oxidation and coking at 1200 ℃. It is used in ethylene cracking furnace tubes, metallurgical direct reduction iron DRI conversion tubes, environmental protection industries, etc. Breaking through the global problem of anti coking of cracking furnace tubes in the petrochemical industry, the comprehensive performance has reached the international leading level. It can bring economic benefits of more than 30 billion yuan to the domestic ethylene industry every year and reduce emissions of 6 million tons/year of standard coal for the country.

Anti coking: Extend the cleaning cycle by 2-5 times and reduce the number of cleaning times
Antioxidant: Complete antioxidant at 1200 ℃ reduces damage to the outer wall of the furnace tube, maintains effective load-bearing area, and extends the service life of the furnace tube by 1.5-2 times
Long term service: 1150 ℃ Long term service can optimize cracking parameters, increase COT temperature by 7-15 ℃, and increase ethylene yield by 2-3%

Properties & Cases

NH1949 Basic Properties

The Fe and Ni in the tube have a strong catalytic effect on coking.In the early stage of coking, longitudinalfilamentary coke is formed on the inner wall of the furnace tube.Filamentous coke will reduce the surface quality ofthe tube and promote gas phase coking and free radical coking.In order to efectively isolate the Fe and Ni in the furnace tube from the cracking raw materials and reducecatalytic coking, the usual method is to form an oxide layer on the surface of the furnace tube material, the oxideayer of the traditional material is a chromium oxide layer, and the oxide layer of the new aluminum materialNH1949 is an aluminum oxide layer. Compared with the chromium oxide layer of the traditional material, thealumina layer of the new aluminum material NH1949 has the following advantages.

Microstructure

NH1949 is a cast nickel based alloy containing chromium, iron, aluminum, tungsten, and other trace alloying elements. Its microstructure is composed of carbide precipitates and austenite matrix, which has good structural stability. The presence of carbon and chromium leads to the formation of chromium rich carbides. The high-temperature strength of the alloy is significantly improved by hindering dislocation movement through the precipitation of carbides and the solid solution strengthening effect of tungsten.

Antioxidation property

NH1949 alloy has excellent carburizingproperties, in the mixed atmosphere ofCzHz/Hz at 1100'C for 8 hours ofcarburizing, the carburizing weight ofNH1949 alloy is only 1/10 of the traditionalmaterial NH25-35Mic or NH35-45Mic alloy.

Resistance to carburisation

NH1949 alloy oxidation weight gain rate is low and the amount of spaling is low. The Al₂O₃ film is stable up to1200'C and the surface coverage can still be continuous at more than 95%, The oxide film distribution is uniformand continuous with a dense structure and the matrix interface is tight ensuring that the alloy has excellentcarburizing and coking resistance below 1200°C

High temperature strength

Since the tensile strenath at 1150'c for NH1949 is equivalent to that of 25Cr35NiNb MA and 35Cr45NiNb MA at1100'c , the application temperature of NH1949 can be 50'c hicher than that of traditional materials.

NH1949 Application Case

NH1949 operating for 130 days has a TMT of 1049'C and an absolute pressure ratio of 0.77. The crackingfurnace can continue to operate with no need to stop for de-coking; whilst the traditional material has beenrunning for 47 davs, the TMT of the fumnace tube has reached 1060'c, and the absolute pressure ratio hasreached 0.88, at which time the furnace needs to be stopped for de-coking. The amount of coke produced byNH1949 after 130 days of operation is comparable to that produced by traditional materials after 47 days of operation.

NH1949 Application Status

NH1949 was first used in a 150,000ton/year crackingfurnace since 2020, the fact that 21 furnaces were equippedwith NH1949 technology to the end of 2024. There aredomestic customers, and customers from the United StatesRussia, the Middle East and so on. Furnace types includeLinde,SW, Lummues and CBL.

IP Portfolio

Patent and IP Portfolio

The company has completed the layout ofintellectual property rights in 42 countries aroundthe world, and has obtained the invention patentauthorization from China, the European Union,Japan, Russia, Saudi Arabia, South Africa, SouthKorea, Singapore, Canada, India, Brazil, Ukraineand other countries have completed the first andsecond trials.