A method for rapidly producing a low-oxygen titanium hydride powder

Abstract

This invention provides a rapid method for preparing low-oxygen-content titanium hydride powder, relating to the field of metal chemical technology. The method comprises the following steps: Sp1 raw material preparation, which involves crushing and sieving titanium or titanium alloy ingots, scraps, or chips to obtain particulate raw materials; Sp2 vacuum rolling desorption drying, which involves treating the material at 120–180°C and a vacuum degree ≤10 Pa for 1–2 hours; Sp3 vacuum preheating activation to 300–450°C and holding for 5–30 minutes; Sp4 primary enhanced hydrogenation, which involves injecting or permeating hydrogen gas downwards through a distributed hydrogen supply structure at 500–650°C and 10–100 kPa, causing the hydrogen gas to contact the settled particles in a co-current or counter-current manner to generate hydrogenation products; Sp5 dehydrogenation-deoxygenation coupling, which involves vacuum dehydrogenation at 700–850°C and 0.1–50 Pa and introducing magnesium / calcium vapor for vapor deoxygenation; Sp6 secondary hydrogenation and phase fixation; and Sp7 argon gas replacement, cooling to ≤150°C, followed by cyclone separation and closed filtration to collect the finished product. This method enables the determination of hydrogenation endpoint, stable deoxygenation, continuous closed production, and the acquisition of low-oxygen powder.

Description

Technical Field

[0001] This invention relates to the field of metal chemical technology, specifically to a method for rapidly preparing low-oxygen-content titanium hydride powder. Background Technology

[0002] Titanium hydride powder and titanium hydride alloy powder are widely used in powder metallurgy, metal injection molding, and additive manufacturing. Their common preparation route is based on the hydrogenation-dehydrogenation method, which involves hydrogenating and embrittlement of titanium or titanium alloy raw materials, followed by dehydrogenation, pulverization, and classification to obtain the target powder. Current industrial hydrogenation processes mainly employ intermittent vacuum hydrogenation furnaces or continuous vacuum atmosphere rotary kilns.

[0003] Intermittent vacuum hydrogenation furnaces typically use trays or cylinders for loading, with the material heated and in contact with hydrogen in a stacked layer. This method limits the gas-solid contact area due to the thickness of the material layer, resulting in a long diffusion path for hydrogen within the layer. Uneven local heat and mass transfer leads to a long hydrogenation induction period, low hydrogenation rate, and poor batch-to-batch consistency. Furthermore, it suffers from frequent loading and unloading, high labor intensity, and limited production cycle time. Continuous vacuum rotary kilns rely on the rotating cylinder to create a tumbling material curtain for contact. However, the gas-solid contact varies with the curtain's shape, resulting in a wide residence time distribution. Micro-leakage and secondary oxygen absorption caused by end sealing and high-temperature material movement are difficult to avoid, leading to fluctuations in the finished product's oxygen content. It is particularly difficult to consistently obtain low-oxygen powder under continuous production conditions. Simultaneously, traditional processes often use fixed holding times as the endpoint control, lacking online criteria and closed-loop regulation based on gas composition, flow rate, and pressure drop. This results in over- or under-reaction, increased energy consumption, inconsistent powder quality, and low-oxygen failure.

[0004] Therefore, there is an urgent need for a preparation method that can achieve efficient and uniform hydrogenation, low-oxygen deoxidation, endpoint determination, and full-process closed low-oxygen assurance under continuous production conditions, so as to improve preparation efficiency and stably obtain low-oxygen titanium hydride powder or titanium hydride alloy powder. Summary of the Invention

[0005] Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a rapid method for preparing low-oxygen-content titanium hydride powder, thus solving the problems of existing technologies.

[0007] Technical solution

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for rapidly preparing low-oxygen-content titanium hydride powder, the method comprising the following steps:

[0009] Sp1: Raw material preparation, which involves crushing and screening titanium or titanium alloy ingots, scraps or chips to obtain particulate raw materials;

[0010] Sp2: Vacuum rolling desorption drying, the particulate raw material is placed in a pretreatment tank and rolled and heated, and treated for 1 to 2 hours at a temperature of 120 to 180℃ and a vacuum degree of ≤10Pa.

[0011] Sp3: Preheating and activation. The granular raw material treated with Sp2 is fed into the preheating section through a lock-in feeding method. It is heated to 300-450°C under a vacuum atmosphere and held for 5-30 minutes.

[0012] Sp4: Primary enhanced hydrogenation, in which particulate raw materials preheated and activated by Sp3 are transported to the primary hydrogenation section, where hydrogenation reaction is carried out at a temperature of 500-650℃ and a hydrogen pressure of 10-100kPa. Hydrogen is supplied downward by a distributed hydrogen supply structure through injection or permeation, so that the hydrogen and the particulate raw materials falling from top to bottom form a co-current or counter-current contact to generate titanium hydride or titanium hydride alloy.

[0013] Sp5: Dehydrogenation-deoxygenation coupling, the material after Sp4 hydrogenation is transported to the dehydrogenation and deoxygenation section, where excess hydrogen is removed by vacuuming at a temperature of 700-850℃ and a vacuum degree of 0.1-50Pa, and deoxidizer steam is introduced into the dehydrogenation and deoxygenation section. The deoxidizer steam is magnesium steam, calcium steam, or a mixture of magnesium steam and calcium steam to reduce the oxygen content of the material.

[0014] Sp6: Secondary hydrogenation and phase fixation. The material treated by Sp5 is transported to the secondary hydrogenation section and secondary hydrogenation is carried out at a temperature of 450-600℃ and a hydrogen pressure of 5-60kPa to regulate the composition and hydrogen content of the hydrogenated phase.

[0015] Sp7: Inert displacement cooling and closed collection. After secondary hydrogenation, argon gas is introduced to replace the hydrogen gas, and the material is cooled to ≤150℃ under argon atmosphere. Low oxygen content titanium hydride powder or titanium hydride alloy powder is obtained by cyclone separation and closed filtration.

[0016] Preferably, the particle size of the particulate raw material in Sp1 is 0.2-3 mm, and the purity of the raw material is ≥99.5%; when the raw material is chips, a degreasing step is added before Sp2, in which the chips are heated to 200-350°C under an inert atmosphere and held for 0.5-2 hours to remove oil and organic residues.

[0017] Preferably, the hydrogen in Sp4 is provided by an active hydrogen generation step, which is performed as follows: hydrogen is introduced into an active hydrogen generator and subjected to thermal or catalytic cracking at a temperature of 650–900°C to obtain hot hydrogen containing active hydrogen components, which is then transported to the inlet of the primary hydrogenation section through an insulated transport pipe, wherein the length of the insulated transport pipe is ≤1.5m and the pipe wall temperature is ≥450°C.

[0018] Preferably, the primary hydrogenation section of Sp4 adopts a cyclone settling bed operation mode. Hydrogen enters the primary hydrogenation section through a tangential inlet to form a cyclone gas curtain, and the material settles along the axial direction. By measuring the pressure drop ΔP within the primary hydrogenation section and adjusting the feeding rate, ΔP is maintained at 50-400 Pa.

[0019] Preferably, the distributed hydrogen supply structure of Sp4 satisfies one of the following:

[0020] The distributed hydrogen supply structure is a micro-nozzle array with a nozzle orifice diameter of 0.3–1.2 mm, a downward spray direction, and a spray angle of 5–30°.

[0021] The distributed hydrogen supply structure is a porous metal permeation plate with a pore size of 5-50 μm, and the permeation direction is from the outside to the inside and downward to form a hydrogen permeation curtain.

[0022] Preferably, the primary enhanced hydrogenation of Sp4 adopts a pulsed hydrogen supply method, in which a pulsed flow rate is superimposed on the continuous baseline hydrogen supply flow rate, the pulse period is 10-60s, the pulse duration is 1-5s, and the peak pulse flow rate is 1.05-1.30 times the baseline flow rate.

[0023] Preferably, the dehydrogenation and deoxygenation section of Sp5 is divided into three sections along the material flow direction and each section satisfies the following conditions:

[0024] The temperature of the first-stage dehydrogenation main zone is 700–760℃ and the vacuum degree is 5–20 Pa.

[0025] The second deoxidation reaction zone has a temperature of 760–830℃ and a vacuum degree of 0.5–5Pa, and deoxidizer vapor is introduced in this zone.

[0026] The temperature in the third cleaning stable zone is 720–780℃ and the vacuum degree is 0.5–3 Pa.

[0027] Preferably, the deoxidizer vapor in Sp5 is generated by an independent evaporator and introduced into the dehydrogenation and deoxidation section through an insulated transport channel; when the deoxidizer vapor is magnesium vapor, the evaporator temperature is 650-780℃; when the deoxidizer vapor is calcium vapor, the evaporator temperature is 750-900℃; the wall temperature of the insulated transport channel is ≥450℃ and the inlet is located in the deoxidation reaction zone.

[0028] Preferably, downstream of the dehydrogenation and deoxygenation section of Sp5, a high-temperature filtration and collection step and a condensation and collection step are sequentially arranged. The high-temperature filtration and collection step uses a sintered metal filter element to collect MgO and CaO particles at 600-850°C, and the condensation and collection step collects metal vapor condensate at 50-250°C. In Sp7, the oxygen content of the argon gas inlet for replacement is ≤20ppm and the dew point is ≤-60°C.

[0029] Preferably, a control method corresponding to a rapid preparation method for low-oxygen-content titanium hydride powder is provided, wherein the control method is performed according to the following steps:

[0030] Sp1: Solid-phase flux closed-loop control, collects the pressure drop ΔP within the primary hydrogenation section and the rotation speed or opening of the feeding mechanism, compares ΔP with the target pressure drop range of 50-400Pa, and adjusts the rotation speed or opening of the feeding mechanism to keep ΔP between 50 and 400Pa.

[0031] Sp2: Endpoint criterion and segmentation control for primary hydrogenation. The inlet hydrogen volume fraction C_in and outlet hydrogen volume fraction C_out of the primary hydrogenation stage are collected, and ΔC = C_in - C_out is calculated. Simultaneously, the hydrogen mass flow rate is collected. And calculate the relative rate of change over a continuous 180 seconds. When ΔC ≤ 0.30 vol% and R ≤ 0.02, the material is switched to the dehydrogenation and deoxygenation section.

[0032] Sp3: Closed-loop control of dehydrogenation and deoxygenation steam supply. Vacuum and temperature data are collected from the main dehydrogenation zone, deoxygenation reaction zone, and scavenging and stabilization zone, and controlled to remain within specified ranges. Simultaneously, oxygen content (O_tail) and dew point (D_tail) of the tail gas from the dehydrogenation and deoxygenation section are collected. When O_tail > 20 ppm or D_tail > -60℃, the deoxidizer steam supply rate is increased and the feeding rate is decreased. When O_tail ≤ 20 ppm and D_tail ≤ -60℃ for 300 seconds, the current deoxidizer steam supply rate and feeding rate are maintained.

[0033] Sp4: Interlocked control of displacement, cooling and collection. After the secondary hydrogenation is completed, the volume fraction of hydrogen C_H2 in the system is collected and argon gas is introduced for displacement. Cooling is started after C_H2≤1.0vol%. The material temperature T_m is collected and the closed cyclone separation and closed filtration collection steps are allowed to be started under the condition that T_m≤150℃.

[0034] Beneficial effects

[0035] This invention provides a rapid method for preparing low-oxygen-content titanium hydride powder. It has the following beneficial effects:

[0036] 1. The present invention and method adopt a continuous reaction mode of sedimentation bed in Sp4, combined with the downward injection or downward permeation supply of distributed hydrogen supply structure, and maintain the solid phase in the dilute phase sedimentation range through ΔP closed loop, so as to stabilize the gas-solid contact area and reduce the boundary layer resistance; superimposed pulse hydrogen supply and ΔC, R endpoint criterion segment control, realize the quantification and repeatability of hydrogenation process, shorten the time to reach hydrogenation steady state and suppress under-hydrogenation and over-hydrogenation.

[0037] 2. This method employs a coupled route of vacuum dehydrogenation and steam deoxygenation in Sp5. Dehydrogenation is carried out by vacuuming at 700–850℃ and 0.1–50Pa, and magnesium / calcium steam is introduced into the deoxygenation reaction zone for metal thermal reduction. Byproducts are captured by high-temperature filter cartridges and condensed and cut off in a graded manner to prevent MgO / CaO and metal condensates from entering the finished powder. The steam supply rate and feeding rate are adjusted by O_tail and D_tail closed loop to achieve a stable reduction in oxygen content under continuous production conditions.

[0038] 3. This method forms a continuous material flow from Sp2 to Sp7, combined with airlock feeding, displacement cooling and closed collection, to isolate the high-temperature stage from the collection stage; the control method uses ΔP, ΔC, R, O_tail, D_tail, C_H2 and T_m to form a closed loop and interlock, to ensure that the cutting, deoxidation intensity and displacement collection meet the determined threshold, reduce manual dependence and improve operational stability and safety. Attached Figure Description

[0039] Figure 1 This is a flowchart of the method of the present invention;

[0040] Figure 2 This is a schematic diagram of the gas-lock feeding and vacuum rolling desorption drying process of the present invention;

[0041] Figure 3 This is a schematic diagram of the preheating activation section and the primary enhanced hydrogenation section of the present invention;

[0042] Figure 4 This is a schematic diagram of the distributed hydrogen supply structure of the present invention;

[0043] Figure 5 This is a schematic diagram of the three-section temperature zone and stepped vacuum of the dehydrogenation-deoxygenation coupling section of the present invention;

[0044] Figure 6 This is a schematic diagram of the trapping chain and inert displacement cooling closed collection process of the present invention;

[0045] Figure 7 This is a logic block diagram of the control method of the present invention;

[0046] Figure 8 This is a schematic diagram of the dual evaporator switching valve sequence and interlocking logic of the present invention. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation Example 1:

[0049] like Figures 1 to 8 As shown, a rapid method for preparing low-oxygen-content titanium hydride powder is described, the method comprising the following steps:

[0050] Sp1: Raw material preparation, which involves crushing and screening titanium or titanium alloy ingots, scraps or chips to obtain particulate raw materials;

[0051] 1. Raw Material Form and Objective: The "particulate raw material" output from Sp1 is used for subsequent continuous reaction in the settling bed. Its objective is not to obtain the final particle size powder in one step, but to obtain intermediate particles that can settle stably, be heated stably, and have stable contact with the gas. The geometric shape of the particulate raw material is controlled to be "near-equivalent particle size" or "short flake / short strip particles" to avoid long strips of chips bridging and entanglement in the settling bed, which would cause flux fluctuations.

[0052] 2. Crushing and Screening Process Chain: Crushing employs a two-stage crushing route. The first stage, shear crushing, cuts long chips to a length ≤10mm, while the second stage, toothed roller or hammer crushing, further crushes them to the target particle size range. Screening employs a two-stage screening process, first removing coarse particles >3mm, and then removing fine powder <0.2mm. The purpose of removing fine powder is to reduce dust entrainment in the high-temperature section, reduce the filter element load, and improve the stability of the gas-solid field within the section.

[0053] 3. Impurity control points: The contact parts of crushing and screening are made of wear-resistant stainless steel or hardened coating. Ordinary carbon steel that is prone to shedding chips is prohibited to prevent the introduction of Fe. Dry or inert gas purging is used during the processing. Chlorine- or sulfur-containing cleaning agents are prohibited to prevent subsequent high-temperature corrosion and the introduction of impurities.

[0054] 4. Inter-segment correlation: The control of particle size distribution by Sp1 directly determines the controllability of pressure drop ΔP in Sp4 segment; an increase in the proportion of coarse particles will lead to insufficient residence time, and an increase in the proportion of fine powder will lead to entrainment and blockage. Both of these will destroy the stability of the endpoint criterion of Sp4 and the stability of low oxygen closed loop in Sp5.

[0055] Sp2: Vacuum rolling desorption drying, the particulate raw material is placed in a pretreatment tank and rolled and heated, and treated for 1 to 2 hours at a temperature of 120 to 180℃ and a vacuum degree of ≤10Pa.

[0056] 1. Pretreatment tank structure: The pretreatment tank is a closed drum structure with spiral guide ribs or lifting plates inside the drum. The rolling speed is 1 to 8 rpm, and the filling rate is controlled within the effective volume range of 10% to 35%. This allows the particles to continuously tumble and fall during the rolling process, avoiding static accumulation that could lead to localized residual adsorbed water.

[0057] 2. Vacuum and condensation branch: The pretreatment tank's exhaust pipeline is connected in series with the condenser and the collection tank; the condenser temperature is 10-30℃ and is used to condense water vapor and volatiles, while the collection tank is used to collect oil mist or organic volatiles to prevent them from entering the vacuum pump and causing pump oil contamination and pumping speed reduction.

[0058] 3. Desorption Completion Criteria: Dew point and pressure detection points are set on the pretreatment tank tail gas pipeline; when the dew point changes by ≤0.5℃ within 300 seconds and the vacuum degree is stable within ±10% of the set value, desorption is considered to have reached a stable state and enters Sp3. This criterion upgrades Sp2 from fixed-time control to "state-stable control", improving batch consistency.

[0059] 4. Low-oxygen logic connection: The core function of Sp2 is to remove adsorbed water. In the subsequent high-temperature hydrogen / vacuum environment of Sp4 to Sp6, the adsorbed water will be converted into an oxidation source (H2O reacts with the metal surface to form an oxide film). Therefore, Sp2 is the first "oxygen source cut-off" in the low-oxygen system.

[0060] Sp3: Preheating and activation. The granular raw material treated with Sp2 is fed into the preheating section through a lock-in feeding method. It is heated to 300-450°C under a vacuum atmosphere and held for 5-30 minutes.

[0061] 1. Vacuum-lock feeding sequence: The gas-lock feeding adopts a double valve or double lock hopper structure. The upstream loading chamber performs two cycles of "vacuuming - argon filling - vacuuming - argon filling" to ensure that the oxygen content in the loading chamber is ≤20ppm and the dew point is ≤-60℃ before opening the downstream valve to enter the preheating section, thus avoiding air being brought into the vacuum preheating section.

[0062] 2. Uniform temperature in the preheating section: The preheating section is equipped with at least three thermocouples at the top, middle and bottom, and adopts zoned heating control to ensure that the temperature difference within the section is ≤ ±15℃; an excessive temperature difference will cause the cross-sectional temperature difference and reaction rate difference in the Sp4 hydrogenation section, resulting in a local underhydrogenation zone and destroying the endpoint criterion.

[0063] 3. Method for determining the preheating residence time: The residence time is determined by the material flow rate and the effective volume of the preheating section; when the material flow rate increases and the residence time approaches the lower limit of 5 minutes, the DCS automatically increases the set temperature of the preheating section to near the upper limit and at the same time reduces the feeding rate to ensure that the particle temperature reaches the hydrogenation initiation conditions when entering Sp4.

[0064] 4. Activation mechanism and correlation: In a vacuum environment of 300-450℃, the adsorbed layer on the particle surface is further removed, and the temperature is close to the activation zone of the oxide film defect on the titanium alloy surface, which provides a shorter induction period for the dissociation and diffusion of hydrogen molecules in Sp4 hydrogenation, making it easier for Sp4 to reach a rapid steady state.

[0065] Sp4: Primary enhanced hydrogenation, in which particulate raw materials preheated and activated by Sp3 are transported to the primary hydrogenation section, where hydrogenation reaction is carried out at a temperature of 500-650℃ and a hydrogen pressure of 10-100kPa. Hydrogen is supplied downward by a distributed hydrogen supply structure through injection or permeation, so that the hydrogen and the particulate raw materials falling from top to bottom form a co-current or counter-current contact to generate titanium hydride or titanium hydride alloy.

[0066] 1. Operation mode of primary hydrogenation section: The primary hydrogenation section is a vertical settling bed reaction zone. The particulate raw material falls in the form of dilute phase settling to avoid the formation of a material accumulation layer. The dilute phase settling is maintained by the closed loop of pressure drop ΔP in the section (see control method Sp1). This operation mode makes the gas-solid contact area stable and the heat and mass transfer resistance low, which shortens the hydrogenation time from the mechanism.

[0067] 2. Process selection logic for co-current / countercurrent flow: In co-current contact, hydrogen and solid flow downwards together, resulting in a stable temperature field and low risk of dust entrainment; in countercurrent contact, hydrogen flows upwards relative to the falling solid, resulting in higher mass transfer driving force and a higher hydrogenation rate. The system switches between co-current and countercurrent operation by adjusting the hydrogen supply inlet and exhaust outlet positions, with the endpoint criteria ΔC and R as the final control targets.

[0068] 3. Cross-sectional uniformity criteria for distributed hydrogen supply: The hydrogen supply structure must cover the entire reactor cross-section, so that the hydrogen volume fraction fluctuation range at any cross-sectional location is ≤ ±0.5 vol; When the hydrogen concentration distribution across the cross-section is uneven, it will lead to local hydrogen-deficient areas, resulting in insufficiently hydrogenated particles entering Sp5, causing fluctuations in the Sp5 dehydrogenation and deoxygenation load and reducing low-oxygen stability.

[0069] 4. Boundary layer disturbance mechanism of pulsed hydrogen supply: The baseline flow rate provides a stable hydrogen partial pressure, and the pulsed flow rate periodically increases the local Reynolds number and disturbs the boundary layer on the particle surface, thereby increasing the hydrogen diffusion flux; the pulse parameters are set according to the principle of "shortest time to reach the endpoint criterion and ΔP not exceeding the limit" to avoid dust entrainment and filter element load increase caused by excessive pulse strength.

[0070] 5. The significance of the "endpoint-cut-off" engineering of primary hydrogenation: Using ΔC and R as the endpoint criteria, hydrogenation does not depend on a fixed holding time, thereby avoiding ineffective energy consumption and excessive embrittlement caused by over-hydrogenation, and also avoiding the failure mode of "insufficient dehydrogenation and insufficient deoxygenation reaction interface" in the Sp5 dehydrogenation and deoxygenation stage caused by under-hydrogenation.

[0071] Sp5: Dehydrogenation-deoxygenation coupling, the material after Sp4 hydrogenation is transported to the dehydrogenation and deoxygenation section, where excess hydrogen is removed by vacuuming at a temperature of 700-850℃ and a vacuum degree of 0.1-50Pa, and deoxidizer steam is introduced into the dehydrogenation and deoxygenation section. The deoxidizer steam is magnesium steam, calcium steam, or a mixture of magnesium steam and calcium steam to reduce the oxygen content of the material.

[0072] 1. The dual objectives of Sp5: The first objective is dehydrogenation (removing excess hydrogen and hydrogen from unstable hydrogenated phases), and the second objective is deoxygenation (reducing the oxide film on the powder surface and fixing oxygen as MgO / CaO byproducts). Dehydrogenation creates an "activated surface," and deoxygenation utilizes the activated surface to achieve efficient oxygen removal. Both are coupled in the same stage to shorten the overall process time.

[0073] 2. Vacuum extraction structure: The dehydrogenation and deoxygenation section is equipped with multiple extraction ports and throttling valves to achieve vacuum control in different sections; the position of the extraction port is fixedly linked to the position of the steam inlet, so that the deoxidizer steam mainly resides in the deoxygenation reaction zone rather than being extracted upstream, thereby improving deoxygenation efficiency and reducing steam consumption.

[0074] 3. Deoxidizer vapor introduction method: Deoxidizer vapor is generated by an independent evaporator and then enters the deoxidation reaction zone through an insulated transport channel; the temperature of the pipe wall of the insulated transport channel is maintained at ≥450℃ to prevent vapor from condensing in the channel and causing blockage or droplets from entering the reaction zone and causing local pollution.

[0075] 4. Deoxidation reaction mechanism and by-product pathway: Magnesium vapor / calcium vapor undergoes a metallothermic reduction reaction with the oxide film on the powder surface to generate MgO / CaO; by-products migrate downstream with the airflow in the form of solid particles or agglomerates, and are intercepted by downstream high-temperature filtration and condensation capture steps to prevent them from entering the finished powder.

[0076] 5. Necessity of tail gas closed loop: The oxygen content and dew point of the tail gas in the dehydrogenation and deoxygenation section reflect the intensity of oxygen source entry and deoxygenation reaction. When O_tail or D_tail exceeds the limit, the system forms a compensation mechanism of "higher deoxidizer partial pressure + longer residence time" by increasing the steam supply rate and decreasing the feed rate, so as to ensure low oxygen stability from the control level.

[0077] Sp6: Secondary hydrogenation and phase fixation. The material treated by Sp5 is transported to the secondary hydrogenation section and secondary hydrogenation is carried out at a temperature of 450-600℃ and a hydrogen pressure of 5-60kPa to regulate the composition and hydrogen content of the hydrogenated phase.

[0078] 1. Necessity of Sp6: After Sp5, the powder surface is in a highly active state and the hydrogen content is in a transitional state. If it is directly cooled, different batches will experience different degrees of dehydrogenation or re-adsorption along the cooling path, resulting in fluctuations in hydrogen content and phase composition. Sp6 stabilizes the hydrogenated phase back to the target window through controlled temperature and hydrogen partial pressure, achieving "phase fixation and hydrogen fixation".

[0079] 2. Key control points for secondary hydrogenation: The secondary hydrogenation section is equipped with pressure control valves and mass flow control to ensure stable hydrogen partial pressure; simultaneously, an outlet hydrogen concentration monitor is installed to determine whether steady state has been reached. Once steady state is reached, the Sp7 replacement step begins to prevent premature replacement due to insufficient secondary hydrogenation, which could lead to phase composition drift.

[0080] 3. Relevance to subsequent applications: The stable hydrogenated phase composition ensures consistent powder embrittlement, resulting in more stable energy consumption and particle size distribution during subsequent pulverization and classification; it directly contributes to batch-to-batch consistency of MIM and 3D printing powders.

[0081] Sp7: Inert displacement cooling and closed collection. After secondary hydrogenation, argon gas is introduced to replace the hydrogen gas, and the material is cooled to ≤150℃ under argon atmosphere. Low oxygen content titanium hydride powder or titanium hydride alloy powder is obtained by cyclone separation and closed filtration.

[0082] 1. Interlocking relationship between displacement and collection: During the displacement stage, the hydrogen volume fraction C_H2 in the system is monitored online. Cooling is initiated when C_H2 ≤ 1.0 vol%. During the cooling stage, the material temperature T_m is monitored online. Cyclone separation and closed filtration collection valves are allowed to be opened when T_m ≤ 150℃. This interlocking simultaneously meets safety and low oxygen requirements, preventing oxygen intake from being introduced by opening valves at high temperatures.

[0083] 2. Division of labor between cyclone separator and closed filtration: Cyclone separator is used to capture most solid particles, reducing the dust load on the filter; closed filtration is used to trap fine powder and purify the gas, preventing fine powder from escaping and causing environmental and safety risks. The two are connected in series to simultaneously meet the requirements of collection efficiency and continuous operation stability.

[0084] 3. Atmosphere control of the sealed collection tank: The collection tank maintains a slight positive pressure of argon gas and is equipped with a one-way valve to prevent backflow of outside air; the collection tank is equipped with a sampling port for sampling and testing of oxygen and hydrogen content under inert conditions, avoiding secondary oxygen absorption caused by opening the lid for sampling.

[0085] In Sp1, the particle size of the raw material is 0.2-3 mm and the purity of the raw material is ≥99.5%. When the raw material is chips, a degreasing step is added before Sp2. The chips are heated to 200-350°C under an inert atmosphere and held for 0.5-2 hours to remove oil and organic residues.

[0086] 1. Engineering rationale for particle size of 0.2-3mm: The lower limit of 0.2mm is used to reduce the filter blockage and capacity loss caused by particles being entrained into the capture chain by the airflow in Sp4 and Sp5; the upper limit of 3mm is used to ensure that the hydrogenation diffusion path does not exceed the reaction time window and avoid under-hydrogenation of large particles.

[0087] 2. Implementation of purity control ≥99.5%: Raw materials are tested for composition and impurities upon entering the warehouse, with a focus on controlling the content of Fe, C, and N; wear-resistant stainless steel or bushings are used for contact parts of crushing and screening equipment to prevent wear from introducing iron impurities.

[0088] 3. Treatment of exhaust gas from degreasing heat treatment: The exhaust gas from the degreasing section is treated by the condensation and adsorption unit before being discharged to prevent oil mist from polluting the subsequent vacuum system; after degreasing, no visible oil film remains on the surface of the chips and the total organic carbon signal of the exhaust gas decreases and stabilizes.

[0089] The hydrogen in Sp4 is provided by the active hydrogen generation step, which is performed as follows: hydrogen is introduced into the active hydrogen generator and subjected to thermal cracking or catalytic cracking at a temperature of 650-900℃ to obtain hot hydrogen containing active hydrogen components, which is then transported to the inlet of the primary hydrogenation section through an insulated transport pipe with a length ≤1.5m and a pipe wall temperature ≥450℃.

[0090] 1. Structure of active hydrogen generator: The active hydrogen generator has a high-temperature resistant alloy shell and a honeycomb catalytic core or a high specific surface area cracking core inside; during catalytic cracking, the surface of the catalytic core is a Ni-based or W-based active layer, and during thermal cracking, a high-temperature cracking tube is used to achieve partial dissociation of H2.

[0091] 2. Effect of active hydrogen on the induction period: The active hydrogen component increases the surface adsorption and diffusion rate, which shortens the residence time required for Sp4 to reach the same ΔC and R criteria, and increases the tolerance for underhydrogenation risk.

[0092] 3. Engineering control of heat preservation and transportation: The transportation pipeline adopts electric heat tracing or jacket insulation, and at least two temperature monitoring points are set along the line. If the pipe wall temperature is lower than 450℃, the DCS shall prohibit the activation of active hydrogen supply and switch to conventional hot hydrogen to avoid condensation and flow fluctuation.

[0093] The primary hydrogenation section of Sp4 adopts a cyclone settling bed operation mode. Hydrogen enters the primary hydrogenation section through a tangential inlet to form a cyclone gas curtain, and the material settles along the axial direction. By measuring the pressure drop ΔP in the primary hydrogenation section and adjusting the feeding rate, ΔP is maintained at 50-400 Pa.

[0094] 1. The function of the swirling air curtain: The swirling flow formed by tangential air intake makes the hydrogen gas more evenly distributed on the cross section and increases the turbulence intensity, enhances gas-solid mass transfer and weakens local short-circuit flow.

[0095] 2. Pressure drop control and stabilization zone: ΔP is maintained in the dilute phase sedimentation stabilization zone of 50-400 Pa. When it is below 50 Pa, the solid phase concentration is too low, resulting in insufficient production capacity. When it is above 400 Pa, the solid phase concentration is too high, resulting in local accumulation and increased risk of underhydrogenation.

[0096] 3. Swirl and dust control: When the swirling intensity is superimposed with the pulse hydrogen supply, the DCS uses the filter element pressure difference and the exhaust gas dust concentration as constraints to avoid dust entrainment causing the capture chain to exceed the limit.

[0097] Sp4 distributed hydrogen supply structure satisfies one of the following:

[0098] The distributed hydrogen supply structure is a micro-nozzle array with a nozzle orifice diameter of 0.3–1.2 mm, a downward injection direction, and an injection angle of 5–30°.

[0099] The distributed hydrogen supply structure is a porous metal permeation plate with a pore size of 5–50 μm. The permeation direction is from the outside in and downward to form a hydrogen permeation curtain.

[0100] 1. Arrangement rules of micro-nozzle array: The nozzles are evenly distributed around the circumference and at least two rings of spray layers are set to form a staged hydrogen supply; the lower layer nozzles are responsible for compensating for the partial pressure of hydrogen in the middle and later stages, avoiding the upper layer spraying caused by the upper layer spraying being strong at the top and weak at the bottom.

[0101] 2. Hydrogen supply chamber control of porous permeation plate: A hydrogen supply chamber is set on the outside of the permeation plate and a pressure control valve maintains a stable pressure difference, so that the permeation flow rate automatically compensates for the pressure fluctuation of the reactor and ensures the stability of the hydrogen curtain.

[0102] 3. Applicability of the two structures: Micro-nozzle arrays are suitable for scenarios with larger particles and higher throughput; porous permeation plates are suitable for scenarios with higher uniformity requirements and reduce the risk of nozzle clogging.

[0103] The enhanced hydrogenation of Sp4 is carried out using a pulsed hydrogen supply method. The pulsed hydrogen supply is based on the continuous baseline hydrogen supply flow rate with a pulse flow rate superimposed. The pulse period is 10 to 60 seconds, the pulse duration is 1 to 5 seconds, and the peak pulse flow rate is 1.05 to 1.30 times the baseline flow rate.

[0104] 1. Tuning principle: The objective function is "the shortest time to achieve the endpoint criterion", while the constraints are "ΔP does not exceed the upper limit, the filter element pressure difference does not rise too fast, and the outlet hydrogen concentration fluctuation does not exceed the limit".

[0105] 2. Tuning steps: First, obtain the baseline achievement time under no-pulse conditions, then gradually increase the peak value multiple and shorten the period until the achievement time no longer decreases significantly or entrainment or voltage drop anomalies occur, thus determining the optimal pulse parameter window.

[0106] 3. Coupling with endpoint criteria: The pulse parameter makes ΔC decrease faster and R reach the threshold earlier, thereby shortening the Sp4 residence time and increasing productivity.

[0107] The dehydrogenation and deoxygenation section of Sp5 is divided into three sections along the feed direction and each section satisfies the following conditions:

[0108] The temperature of the first-stage dehydrogenation main zone is 700–760℃ and the vacuum degree is 5–20 Pa.

[0109] The second deoxidation reaction zone has a temperature of 760–830℃ and a vacuum degree of 0.5–5Pa, and deoxidizer vapor is introduced in this zone.

[0110] The temperature in the third cleaning stable zone is 720–780℃ and the vacuum degree is 0.5–3 Pa.

[0111] 1. The first stage is mainly for dehydrogenation: higher pressure (5-20 Pa) combined with a larger pumping speed is conducive to the rapid removal of hydrogen and avoids the deoxidizer vapor being consumed in large quantities in this stage.

[0112] 2. The second stage is mainly deoxidation: lower pressure (0.5-5 Pa) increases the mean free path of metal vapor and enhances the effective collision with the particle surface, making the deoxidation reaction more complete.

[0113] 3. The third stage is mainly for cleaning: maintaining low pressure and medium temperature to remove residual steam and volatile by-products, stabilize exhaust gas indicators and reduce downstream capture load.

[0114] In Sp5, the deoxidizer vapor is generated by an independent evaporator and introduced into the dehydrogenation and deoxidation section through an insulated transport channel. When the deoxidizer vapor is magnesium vapor, the evaporator temperature is 650–780℃; when the deoxidizer vapor is calcium vapor, the evaporator temperature is 750–900℃. The wall temperature of the insulated transport channel is ≥450℃ and the inlet is located in the deoxidation reaction zone.

[0115] 1. Evaporator metering: The evaporator adopts a screw metering feeder, and the screw speed is linked to the material level to ensure that the steam supply flux is proportional to the material flow rate; when the material level is lower than the threshold, feeding is triggered and low material level operation is prohibited to avoid O_tail fluctuation caused by intermittent steam supply.

[0116] 2. Dual Evaporation Unit Switching: The evaporator adopts a dual-unit parallel structure. When unit A is running, unit B is fed and preheated. When unit A approaches the low material level, it switches to unit B and unit A enters the feeding and preheating process. The switching process maintains the continuous total steam flux to avoid instantaneous changes in the intensity of the deoxidation reaction.

[0117] 3. Inlet location: The inlet is located at 1 / 3 to 2 / 3 of the inlet of the deoxygenation reaction zone to ensure that the steam has an effective residence distance in the reaction zone and to prevent it from being extracted as soon as it is introduced.

[0118] Downstream of the dehydrogenation and deoxygenation section of Sp5, a high-temperature filtration and collection step and a condensation and collection step are set sequentially. The high-temperature filtration and collection step uses a sintered metal filter element to collect MgO and CaO particles at 600-850℃, and the condensation and collection step collects metal vapor condensate at 50-250℃. In Sp7, the oxygen content of the argon gas inlet for replacement is ≤20ppm and the dew point is ≤-60℃.

[0119] 1. High-temperature filter element differential pressure management: The high-temperature filter element is equipped with differential pressure monitoring ΔP_f. When ΔP_f reaches the set threshold, bypass switching and filter element replacement are performed. Filter element replacement is carried out under an inert atmosphere to prevent air from entering the system and contaminating the reaction section.

[0120] 2. Condensation trap replacement strategy: The condensation trap is replaced based on the increase in quality or the length of operation. When replacing, keep the upstream valve closed and maintain a slight positive pressure of argon gas to prevent backflow.

[0121] 3. Argon supply system: An oxygen and water removal unit is installed at the argon inlet to monitor oxygen content and dew point online; when the inlet oxygen content is >20ppm or the dew point is >-60℃, the DCS will prohibit the entry of Sp7 collection interlock and alarm to avoid oxygen absorption during the low temperature collection stage, which would cause the finished product oxygen to rebound.

[0122] A control method for a rapid preparation method of low-oxygen-content titanium hydride powder is provided, and the control method is carried out according to the following steps:

[0123] Sp1: Solid-phase flux closed-loop control, collects the pressure drop ΔP within the primary hydrogenation section and the rotation speed or opening of the feeding mechanism, compares ΔP with the target pressure drop range of 50-400Pa, and adjusts the rotation speed or opening of the feeding mechanism to keep ΔP between 50 and 400Pa.

[0124] 1. Measurement point layout: The ΔP measurement point is set at the upper and lower parts of the primary hydrogenation section to form a differential pressure. The sampling period is ≤1s and a moving average filter is used to eliminate transient fluctuations introduced by pulse hydrogen supply.

[0125] 2. Actuator: The feeding mechanism adopts a variable frequency drive star valve or metering valve, and the control output adopts PID. The proportional term is used for fast response, and the integral term is used to eliminate steady-state error. When ΔP approaches the upper limit of 400Pa, a limiting strategy is adopted to prevent integral saturation.

[0126] 3. Safety constraints: When ΔP>450Pa for 10 seconds, the system will perform a load reduction action: reduce the feeding rate and reduce the pulse peak value to prevent accumulation and blockage.

[0127] Sp2: Endpoint criterion and segmentation control for primary hydrogenation. The inlet hydrogen volume fraction C_in and outlet hydrogen volume fraction C_out of the primary hydrogenation stage are collected, and ΔC = C_in - C_out is calculated. Simultaneously, the hydrogen mass flow rate is collected. And calculate the relative rate of change over a continuous 180 seconds. When ΔC ≤ 0.30 vol% and R ≤ 0.02, the material is switched to the dehydrogenation and deoxygenation section.

[0128] 1. Sampling and calibration: C_in and C_out are measured using a thermal conductivity or gas analyzer, with a sampling period of ≤2s; zero-point and span calibrations are performed daily to ensure the stability of the ΔC criterion.

[0129] 2. Cutting action sequence: After the criteria are met, first open the switching valve leading to Sp5 and close the bottom buffer valve of Sp4 to allow the material to enter Sp5; at the same time, switch the hydrogen supply of Sp4 from pulse mode to baseline mode to avoid dust entrainment caused by gas-solid field fluctuations during cutting.

[0130] 3. Abnormal protection: If ΔC suddenly increases and R rises, it is determined that the hydrogen supply is abnormal or leaking. The system will stop feeding and maintain vacuum evacuation and argon inerting.

[0131] Sp3: Closed-loop control of dehydrogenation and deoxygenation steam supply, collecting the vacuum degree and temperature of the main dehydrogenation zone, deoxygenation reaction zone, and cleaning and stabilization zone and controlling them to be maintained within the range defined in claim 7, while collecting the oxygen content O_tail and dew point D_tail of the tail gas of the dehydrogenation and deoxygenation section; when O_tail>20ppm or D_tail>-60℃, increasing the deoxidizer steam supply rate and decreasing the feeding rate; when O_tail≤20ppm and D_tail≤-60℃ for 300s, maintaining the current deoxidizer steam supply rate and feeding rate.

[0132] 1. Multivariable coupling control: While the steam supply rate is increased, the DCS synchronously adjusts the second stage pumping speed setpoint to stabilize the pressure in the deoxidation reaction zone at 0.5-5 Pa, thus preventing the steam from being pumped away due to pressure surge caused by the steam increase.

[0133] 2. Significance of dew point and oxygen content: A rise in dew point primarily indicates insufficient water vapor entry or desorption, while a rise in oxygen content primarily indicates leakage or purification failure. The DCS records both separately and generates alarm codes to facilitate the location of the fault source.

[0134] 3. Collection chain constraint: The increase in steam supply rate is constrained by the pressure difference ΔP_f of the high-temperature filter element. When ΔP_f approaches the upper limit, the system prioritizes reducing the feeding rate and maintaining steam supply to avoid filter element blockage and system shutdown.

[0135] Sp4: Interlocked control of displacement, cooling, and collection. After secondary hydrogenation, the hydrogen volume fraction (C_H2) in the system is collected, and argon gas is introduced for displacement. Cooling is initiated after C_H2 ≤ 1.0 vol%. The material temperature (T_m) is collected, and the closed cyclone separation and closed filtration collection steps are allowed to be started when T_m ≤ 150℃.

[0136] 1. Replacement strategy: The replacement adopts a parallel method of "argon gas inlet + extraction" to shorten the time to reach C_H2≤1.0vol%; the Sp6 outlet valve is kept closed during the replacement to avoid dust entrainment caused by argon gas impact.

[0137] 2. Temperature measurement: T_m is jointly calibrated by the cooling section wall temperature and the infrared temperature measurement of the falling material. The collection valve must not be opened when any measuring point exceeds 150℃ to prevent the powder from absorbing oxygen at high temperature and the filter from exceeding the heat load limit.

[0138] 3. Atmosphere maintenance during collection: The collection container is kept under a slight positive pressure of argon gas. After collection is completed, it is automatically sealed and enters an inert sampling mode to ensure that the oxygen content does not rebound during the detection and transportation process.

[0139] Typical dimensions / residence time calculation methods for each section (deriving solids content and residence time from material flow rate, cross-sectional area, and ΔP): Symbols and known quantities:

[0140] Material mass flow rate: (\dot m_s) (kg / s), material true density: (\rho_s) (kg / m³), TC4 is taken as 4400 kg / m³, Ti is taken as 4500 kg / m³, gas density: (\rho_g) (kg / m³), calculated by the equation of state based on segment temperature / pressure, reaction segment cross-sectional area: (A) (m²), reaction segment inner diameter (D) (m), (A=\pi D^2 / 4), reaction segment effective height: (L) (m), segment pressure drop: (\Delta P) (Pa), taking the differential pressure between the upper and lower parts of the segment, gravitational acceleration: (g=9.81) (m / s²), solid volume fraction (solid content): (\varepsilon_s) (dimensionless), solid apparent axial velocity: (v_s) (m / s), solid residence time: (\tau_s) (s), solid content is inferred from ΔP (approximately due to dilute phase sedimentation).

[0141] The primary hydrogenation section operates using dilute phase sedimentation. The pressure drop within this section mainly originates from the solid "equivalent gravity column" and the gas static pressure term. After averaging along the section height, the solid content is calculated using the following formula:

[0142] [\frac{\Delta P}{L}=g\left(\rho_s \varepsilon_s+\rho_g(1-\varepsilon_s)\right)];

[0143] The results were:

[0144] [\varepsilon_s=\frac{\Delta P / (gL)-\rho_g}{\rho_s-\rho_g}];

[0145] When performing engineering calculations, take (\rho_s \gg \rho_g), then:

[0146] [\varepsilon_s \approx \frac{\Delta P}{\rho_s g L}];

[0147] This reverse reasoning method directly corresponds to the ΔP closed loop in your control method. Stability of ΔP means that (\varepsilon_s) is stable.

[0148] Solid velocity and residence time can be inferred from solid content and material flow rate.

[0149] Solid flux (mass flow rate per unit cross section):

[0150] [G_s=\frac{\dot m_s}{A}];

[0151] The velocity of a solid is obtained from the continuity equation:

[0152] [v_s=\frac{G_s}{\rho_s\varepsilon_s}=\frac{\dot m_s}{A\rho_s\varepsilon_s}];

[0153] Average residence time of solids:

[0154] [\tau_s=\frac{L}{v_s}=\frac{LA \rho_s \varepsilon_s}{\dot m_s}];

[0155] This formula is used to deduce the "reaction section height L" or "reaction section diameter D".

[0156] Procedure for determining the size of the reaction section (for Sp3 to Sp6);

[0157] Step 1: Determine the target production capacity (m_s);

[0158] Step-2: Determine the control window (Delta P) and segment height (L) (the primary hydrogenation segment is determined by the structure, and the dehydrogenation and deoxygenation segment is divided into three temperature zones, namely (L_1, L_2, L_3)).

[0159] Step-3: Reverse the above formula to deduce (\varepsilon_s);

[0160] Step-4: Select the inner diameter (D) to obtain the cross-sectional area (A);

[0161] Step-5: Calculate (v_s,\tau_s) and match it with the target stay time window;

[0162] Step-6: If (\tau_s) is too small, increase (L) or decrease (D) (reduce the cross-section to increase solids content and residence time); if (\tau_s) is too large, decrease (L) or increase (D);

[0163] Residence time allocation for the three dehydrogenation and deoxygenation stages:

[0164] The dehydrogenation and deoxygenation section is divided into three heights (L_1, L_2, L_3) under the same feed flow rate:

[0165] [\tau_{s,i}=\frac{L_i A \rho_s \varepsilon_{s,i}}{\dot m_s}];

[0166] Where (\varepsilon_{s,i}) is derived by inversely from (\Delta P_i) and (L_i) of each segment. In engineering implementation, differential pressure measuring points are arranged in the three segments respectively, and their ΔP is closed in the corresponding window to stabilize the residence time distribution of the three segments and ensure the stability of dehydrogenation load and deoxygenation load.

[0167] Design guidelines for the number of micronozzles, nozzle spacing, and permeate plate area (Sp4 distributed hydrogen supply)

[0168] Micro-nozzle array: Determining the number of nozzles N:

[0169] Given the total hydrogen volumetric flow rate (operating volumetric flow rate) (Q_{H2}) (m³ / s) required for the primary hydrogenation stage, select the nozzle orifice diameter (d_n) (m) and the nozzle flow area (A_n = π d_n^2 / 4). Take a controllable injection pressure difference (Delta P_n) (Pa) at the nozzle outlet, and the gas density at the nozzle (rho_{H2}).

[0170] The flow rate of a single nozzle is calculated using the orifice flow formula:

[0171] [q_n=C_d A_n \sqrt{\frac{2\Delta P_n}{\rho_{H2}}}];

[0172] The flow coefficient (C_d) is set to 0.80 to 0.95 and fixed in the design file.

[0173] Number of nozzles:

[0174] [N=\frac{Q_{H2}}{q_n}];

[0175] Engineering constraints:

[0176] The nozzle exit velocity (u_n=q_n / A_n) is set in the range of 20 to 120 m / s;

[0177] When (u_n) exceeds the range, (N) is recalculated by adjusting (d_n) or (\Delta P_n);

[0178] Micro-nozzle array: Nozzle spacing S and coverage uniformity:

[0179] The diffusion half-angle of the jet beam at the axial distance (z) is taken as (\beta) (°), and the design documents fix it at 8°~15°. Jet beam radius:

[0180] [r(z)=z\tan\beta];

[0181] In the "hybrid verification plane," take (z_m), which is set to be (0.3D) to (0.6D) below the nozzle plane. To achieve cross-sectional coverage, the nozzle spacing must satisfy:

[0182] [S \le 2r(z_m)=2z_m\tan\beta];

[0183] When arranged in a ring, the number of circumferential nozzles (N_\theta) satisfies: [N_\theta \ge \frac{\pi D}{S}];

[0184] When using two-ring nozzles, the upper ring supplies 60% to 80% of the hydrogen and the lower ring supplies 20% to 40% of the hydrogen. The axial distance between the two rings is (0.15D) to (0.30D) to correct the downstream hydrogen partial pressure and suppress the strong upper pressure and weak lower pressure.

[0185] Permeation plate: Area (A_p) and permeation flux:

[0186] The permeation plate has a pore size of 5-50 μm. The outer side of the permeation plate is a hydrogen supply chamber. The pressure in the hydrogen supply chamber (P_{pl}) is higher than the reactor pressure (P_r), and the pressure difference is (\Delta P_{pl}=P_{pl}-P_r).

[0187] Average surface velocity of the permeation plate (apparent velocity of permeation): [u_p=\frac{Q_{H2}}{A_p}];

[0188] The design documents fix (u_p) within the range of 0.02–0.20 m / s to ensure uniform permeation and suppress entrainment caused by local jet penetration. Therefore, the permeation plate area is calculated as: [A_p = \frac{Q_{H2}}{u_p}];

[0189] The length (L_p) of the permeation plates along the height is (0.4L) to (0.8L) to establish a stable hydrogen curtain. The circumferential coverage angle of the permeation plates is 240° to 360°. If the coverage is insufficient, two symmetrical permeation plates are set to cover the entire cross-section.

[0190] Cyclone separator cutting particle size, filter element filtration area, differential pressure threshold engineering selection logic (Sp7 collection section).

[0191] Determination of cyclone cutting particle size (d_{50}) (Lapple model path):

[0192] A standard cyclone proportion structure is adopted, with the cyclone cylinder diameter (D_c), inlet width (a), and inlet height (b) defined. The proportions are fixed as follows:

[0193] (a=0.20D_c);

[0194] (b=0.50D_c);

[0195] The inlet gas velocity (V_i) is determined by the operating gas volume (Q_g) and the inlet cross section (ab): [V_i=\frac{Q_g}{ab}];

[0196] The effective number of rotations (N_e) is determined by the structural height and is fixed in the design documents (N_e=4)~(6).

[0197] Lapple cutting particle size: [d_{50}=\sqrt{\frac{9\mu b}{2\rho_p V_i N_e}}];

[0198] in:

[0199] (\mu) represents the gas viscosity (Pa·s);

[0200] (\rho_p) represents particle density (kg / m³);

[0201] Selection process:

[0202] Step-1: The inlet velocity (V_i) is given by the system exhaust gas volumetric flow rate (Q_g);

[0203] Step-2: Set the target cutting particle size (d_{50}) (related to the product dust particle size distribution; the cutting particle size is lower than the particle size corresponding to the filter element load limit).

[0204] Step-3: Reverse the above equation to deduce (D_c) or adjust (V_i);

[0205] Step-4: The dust concentration at the cyclone outlet enters the filter section, so that the filter mainly "intercepts fine powder" and the cyclone mainly "unloads large particles".

[0206] Inlet velocity constraint: (V_i) is fixed in the range of 12 to 25 m / s. Below 12 m / s, the cutting particle size increases, and above 25 m / s, the pressure drop increases significantly and wear increases.

[0207] Determining the filter element's filtration area (A_f):

[0208] The air volume of the filter element section is taken as the air volume after the cyclone (Q_f), and the filter element surface velocity (apparent filtration velocity) is set to (v_f). Under high-temperature dust conditions, (v_f) is fixed in the range of 0.02 to 0.08 m / s. Total filter element filtration area: [A_f=\frac{Q_f}{v_f}];

[0209] The number of filter cartridges (N_f) is determined by the area of ​​a single filter cartridge (A_{1}): [N_f=\left\lceil\frac{A_f}{A_1}\right\rceil];

[0210] The filter element material is sintered metal with a temperature resistance of 600–850℃. The filter element pore size is fixed at 1–10 μm according to the system dust spectrum and locked in the design documents.

[0211] Engineering settings for differential pressure thresholds (alarm / interlock):

[0212] Set three threshold values ​​for the filter element section pressure difference (Delta P_f) as the basis for DCS interlocking:

[0213] Normal operating range: (Delta P_f = 0.5)~2.0 kPa;

[0214] Alarm threshold: (Delta P_f = 3.0) kPa, triggering "load reduction + bypass preparation";

[0215] Trip threshold: (Delta P_f = 4.0) kPa, triggering "stop feeding + displacement inerting + close collection valve";

[0216] The cyclone pressure differential (\Delta P_c) is set to 0.6~2.5 kPa. If (\Delta P_c) exceeds the upper limit, the DCS will reduce the system air volume and check the inlet velocity, wear leakage and dust accumulation.

[0217] Evaporator Dual-Unit Switching Valve Sequence and Interlock Table: Two evaporation units are defined below: Evaporator A and Evaporator B. Both are connected in parallel to the same steam main, which leads into the deoxygenation reaction zone. Each evaporator unit includes: a feed screw, crucible heating, steam outlet valve, vacuum valve, argon purging valve, and temperature / pressure / level signals.

[0218] Main DCS measurement points:

[0219] TT_A, TT_B: Temperatures of the evaporation crucible;

[0220] LT_A, LT_B: Evaporator material level;

[0221] PT_A, PT_B: Evaporator chamber pressure;

[0222] FT_VAP: Steam main flow rate (or equivalent steam flow rate converted to evaporator feed rate);

[0223] TV_A_OUT, TV_B_OUT: A / B steam outlet valve opening;

[0224] SV_A_VAC, SV_B_VAC: Status of A / B vacuum valves;

[0225] SV_A_AR, SV_B_AR: Status of A / B argon displacement valve;

[0226] DP_F: High-temperature filter element pressure difference;

[0227] O_tail, D_tail: Oxygen content and dew point of dehydrogenation and deoxygenation tail gas;

[0228] The valve sequence for dual-unit switching (from A to B);

[0229] Prerequisite (B enters the switching state);

[0230] TT_B reaches the set evaporation temperature range (magnesium 650~780℃, calcium 750~900℃);

[0231] PT_B is in the set vacuum range;

[0232] LT_B is higher than the low material level threshold;

[0233] Switching sequences (fixed timing):

[0234] Step-1: Lock the FT_VAP target value to the current set value;

[0235] Step-2: Turn TV_B_OUT on to the initial opening (x_0), and at the same time turn off TV_A_OUT proportionally, so that FT_VAP is kept at the target value ±2%;

[0236] Step-3: Within 30 to 120 seconds, linearly increase TV_B_OUT to the working degree and linearly decrease TV_A_OUT to 0;

[0237] Step-4: After turning off TV_A_OUT, keep SV_A_VAC on and maintain vacuum in chamber A for residual vapor purging for 60-300 seconds;

[0238] Step 5: Execute the A-level material replenishment process: Turn off SV_A_VAC, turn on SV_A_AR to displace until PT_A reaches the displacement pressure, turn off SV_A_AR, open the lid to replenish material, close the lid after replenishment, and perform vacuuming and preheating.

[0239] Step-6: A enters "hot standby" mode, waiting for the next switchover;

[0240] This valve sequence ensures continuous total steam flow and avoids fluctuations in O_tail and D_tail.

[0241] Interlock Table (Core Interlock Conditions and Actions):

[0242] Interlock I: Low material level interlock;

[0243] Conditions: LT_A ≤ LLL and TV_A_OUT > 0;

[0244] Action: Reduce TV_A_OUT to 0 and initiate switch to B; if B does not meet the prerequisites, stop feeding and maintain vacuum extraction;

[0245] Interlock II: Evaporation temperature interlock;

[0246] Conditions: TT_A is below the lower limit of the evaporation temperature and TV_A_OUT > 0;

[0247] Action: Turn off TV_A_OUT and trigger an alarm; initiate switchover to B; if B does not meet the preconditions, reduce the feeding rate and increase the extraction rate;

[0248] Interlock III: Pressure runaway interlock;

[0249] Conditions: PT_A is higher than the set upper limit and TV_A_OUT > 0;

[0250] Actions: Turn off TV_A_OUT, turn on SV_A_VAC; maintain the vacuum setting of the deoxidation section of the system and reduce the feeding rate;

[0251] Interlock IV: Filter element pressure differential constraint interlock:

[0252] Condition: DP_F ≥ 3.0 kPa;

[0253] Action: Maintain steam supply flux at a constant level and reduce feed rate; stop feeding and inerting when DP_F ≥ 4.0 kPa.

[0254] Interlock V: Exhaust gas low oxygen index interlock:

[0255] Conditions: O_tail > 20 ppm or D_tail > -60℃

[0256] Action: Increase the FT_VAP setting and decrease the feeding rate; if it does not recover for 600 seconds, stop feeding and perform inertization replacement.

[0257] Evaporator feed interlock (prevents the introduction of oxygen source during feed) Feeding allowable conditions: TV_OUT=0, PT ≤ 100Pa, SV_VAC off, SV_AR on and completed 2 replacement cycles, O2≤20ppm, dew point≤-60℃. If any condition is not met, the feed operation is locked and prohibited.

[0258] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a reference structure" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0259] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for rapidly preparing low-oxygen-content titanium hydride powder, characterized in that, The method is performed according to the following steps: Sp1: Raw material preparation, which involves crushing and screening titanium or titanium alloy ingots, scraps or chips to obtain particulate raw materials; Sp2: Vacuum rolling desorption drying, the particulate raw material is placed in a pretreatment tank and rolled and heated, and treated for 1 to 2 hours at a temperature of 120 to 180℃ and a vacuum degree of ≤10Pa. Sp3: Preheating and activation. The granular raw material treated with Sp2 is fed into the preheating section through a lock-in feeding method. It is heated to 300-450°C under a vacuum atmosphere and held for 5-30 minutes. Sp4: Primary enhanced hydrogenation, in which particulate raw materials preheated and activated by Sp3 are transported to the primary hydrogenation section, where hydrogenation reaction is carried out at a temperature of 500-650℃ and a hydrogen pressure of 10-100kPa. Hydrogen is supplied downward by a distributed hydrogen supply structure through injection or permeation, so that the hydrogen and the particulate raw materials falling from top to bottom form a co-current or counter-current contact to generate titanium hydride or titanium hydride alloy. Sp5: Dehydrogenation-deoxygenation coupling, the material after Sp4 hydrogenation is transported to the dehydrogenation and deoxygenation section, where excess hydrogen is removed by vacuuming at a temperature of 700-850℃ and a vacuum degree of 0.1-50Pa, and deoxidizer steam is introduced into the dehydrogenation and deoxygenation section. The deoxidizer steam is magnesium steam, calcium steam, or a mixture of magnesium steam and calcium steam to reduce the oxygen content of the material. Sp6: Secondary hydrogenation and phase fixation. The material treated by Sp5 is transported to the secondary hydrogenation section and secondary hydrogenation is carried out at a temperature of 450-600℃ and a hydrogen pressure of 5-60kPa to regulate the composition and hydrogen content of the hydrogenated phase. Sp7: Inert displacement cooling and closed collection. After secondary hydrogenation, argon gas is introduced to replace the hydrogen gas, and the material is cooled to ≤150℃ under argon atmosphere. Low oxygen content titanium hydride powder or titanium hydride alloy powder is obtained by cyclone separation and closed filtration.

2. The method for rapidly preparing low-oxygen-content titanium hydride powder according to claim 1, characterized in that: The particle size of the particulate raw material in Sp1 is 0.2-3 mm, and the purity of the raw material is ≥99.5%. When the raw material is chips, a degreasing step is added before Sp2. The chips are heated to 200-350°C under an inert atmosphere and held for 0.5-2 hours to remove oil and organic residues.

3. The method for rapidly preparing low-oxygen-content titanium hydride powder according to claim 1, characterized in that: The hydrogen in Sp4 is provided by an active hydrogen generation step, which is performed as follows: hydrogen is introduced into an active hydrogen generator and subjected to thermal or catalytic cracking at a temperature of 650–900°C to obtain hot hydrogen containing active hydrogen components, which is then transported to the inlet of the primary hydrogenation section through an insulated transport pipe with a length ≤1.5m and a pipe wall temperature ≥450°C.

4. The method for rapidly preparing low-oxygen-content titanium hydride powder according to claim 1, characterized in that: The primary hydrogenation section of Sp4 adopts a cyclone settling bed operation mode. Hydrogen enters the primary hydrogenation section through a tangential inlet to form a cyclone gas curtain, and the material settles along the axial direction. By measuring the pressure drop ΔP within the primary hydrogenation section and adjusting the feeding rate, ΔP is maintained at 50-400 Pa.

5. The method for rapidly preparing low-oxygen-content titanium hydride powder according to claim 1, characterized in that: The distributed hydrogen supply structure described in Sp4 satisfies one of the following: The distributed hydrogen supply structure is a micro-nozzle array with a nozzle orifice diameter of 0.3–1.2 mm, a downward spray direction, and a spray angle of 5–30°. The distributed hydrogen supply structure is a porous metal permeation plate with a pore size of 5-50 μm, and the permeation direction is from the outside to the inside and downward to form a hydrogen permeation curtain.

6. The method for rapidly preparing low-oxygen-content titanium hydride powder according to claim 1, characterized in that: The enhanced hydrogenation of Sp4 is carried out using a pulsed hydrogen supply method. The pulsed hydrogen supply is based on the continuous baseline hydrogen supply flow rate with a pulse flow rate superimposed. The pulse period is 10 to 60 seconds, the pulse duration is 1 to 5 seconds, and the peak pulse flow rate is 1.05 to 1.30 times the baseline flow rate.

7. The method for rapidly preparing low-oxygen-content titanium hydride powder according to claim 6, characterized in that: The dehydrogenation and deoxygenation section of Sp5 is divided into three sections along the material flow direction and each section satisfies the following conditions: The temperature of the first-stage dehydrogenation main zone is 700–760℃ and the vacuum degree is 5–20 Pa. The second deoxidation reaction zone has a temperature of 760–830℃ and a vacuum degree of 0.5–5Pa, and deoxidizer vapor is introduced in this zone. The temperature in the third cleaning stable zone is 720–780℃ and the vacuum degree is 0.5–3 Pa.

8. The method for rapidly preparing low-oxygen-content titanium hydride powder according to claim 6, characterized in that: In Sp5, the deoxidizer vapor is generated by an independent evaporator and introduced into the dehydrogenation and deoxidation section through an insulated transport channel; when the deoxidizer vapor is magnesium vapor, the evaporator temperature is 650-780℃; when the deoxidizer vapor is calcium vapor, the evaporator temperature is 750-900℃; the wall temperature of the insulated transport channel is ≥450℃ and the inlet is located in the deoxidation reaction zone.

9. The method for rapidly preparing low-oxygen-content titanium hydride powder according to claim 6, characterized in that: Downstream of the dehydrogenation and deoxygenation section of Sp5, a high-temperature filtration and collection step and a condensation and collection step are sequentially arranged. The high-temperature filtration and collection step uses a sintered metal filter element to collect MgO and CaO particles at 600-850℃, and the condensation and collection step collects metal vapor condensate at 50-250℃. In Sp7, the oxygen content of the argon gas inlet for replacement is ≤20ppm and the dew point is ≤-60℃.

10. The control method corresponding to the method for rapidly preparing low-oxygen-content titanium hydride powder according to any one of claims 1-9, characterized in that: The control method is performed according to the following steps: Sp1: Solid-phase flux closed-loop control, collects the pressure drop ΔP within the primary hydrogenation section and the rotation speed or opening of the feeding mechanism, compares ΔP with the target pressure drop range of 50-400Pa, and adjusts the rotation speed or opening of the feeding mechanism to keep ΔP between 50 and 400Pa. Sp2: Endpoint criterion and segmentation control for primary hydrogenation. The inlet hydrogen volume fraction C_in and outlet hydrogen volume fraction C_out of the primary hydrogenation stage are collected, and ΔC = C_in - C_out is calculated. Simultaneously, the hydrogen mass flow rate is collected. And calculate the relative rate of change over a continuous 180 seconds. When ΔC ≤ 0.30 vol% and R ≤ 0.02, the material is switched to the dehydrogenation and deoxygenation section. Sp3: Closed-loop control of dehydrogenation and deoxygenation steam supply, collecting the vacuum degree and temperature of the main dehydrogenation zone, deoxygenation reaction zone, and cleaning and stabilization zone and controlling them to be maintained within the range defined in claim 7, while collecting the oxygen content O_tail and dew point D_tail of the tail gas of the dehydrogenation and deoxygenation section; when O_tail>20ppm or D_tail>-60℃, increasing the deoxidizer steam supply rate and decreasing the feeding rate; when O_tail≤20ppm and D_tail≤-60℃ for 300s, maintaining the current deoxidizer steam supply rate and feeding rate. Sp4: Interlocked control of displacement, cooling and collection. After the secondary hydrogenation is completed, the volume fraction of hydrogen C_H2 in the system is collected and argon gas is introduced for displacement. Cooling is started after C_H2≤1.0vol%. The material temperature T_m is collected and the closed cyclone separation and closed filtration collection steps are allowed to be started under the condition that T_m≤150℃.

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