CN114408869B - Sodium sulfide production system and process for gas-phase fluidization reduction of sodium sulfate - Google Patents

Sodium sulfide production system and process for gas-phase fluidization reduction of sodium sulfate Download PDF

Info

Publication number
CN114408869B
CN114408869B CN202210256561.2A CN202210256561A CN114408869B CN 114408869 B CN114408869 B CN 114408869B CN 202210256561 A CN202210256561 A CN 202210256561A CN 114408869 B CN114408869 B CN 114408869B
Authority
CN
China
Prior art keywords
gas
fluidized bed
phase
bed reactor
reducing gas
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202210256561.2A
Other languages
Chinese (zh)
Other versions
CN114408869A (en
Inventor
刘志盛
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
China National Coal Group Corp
Original Assignee
China National Coal Group Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by China National Coal Group Corp filed Critical China National Coal Group Corp
Publication of CN114408869A publication Critical patent/CN114408869A/en
Application granted granted Critical
Publication of CN114408869B publication Critical patent/CN114408869B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B17/00—Sulfur; Compounds thereof
    • C01B17/22—Alkali metal sulfides or polysulfides
    • C01B17/24—Preparation by reduction
    • C01B17/28—Preparation by reduction with reducing gases
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity
    • C01P2006/82—Compositional purity water content
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency
    • Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)

Abstract

The invention relates to the technical field of sodium sulfide industrial production, and provides a production system and a process for preparing sodium sulfide by gas-phase fluidization reduction of sodium sulfate, wherein the production system consists of five units, namely sodium sulfate fluidization heating, reducing gas heating, sodium sulfate fluidization reduction reaction, product waste heat recovery and cooling, and product packaging; the process method comprises the following steps: (1) Mixing sodium sulfate, catalyst and superheated steam in a deoxidizing heater, heating, deoxidizing and separating; (2) Heating the solid phase raw material step by step and then feeding the solid phase raw material into a fluidized bed reactor; (3) heating the reducing gas step by step and then feeding the reducing gas into the fluidized bed reactor; (4) The reducing gas reacts with sodium sulfate in the fluidized bed reactor; and (5) recovering the waste heat of the solid product, removing iron electromagnetically and packaging. The invention realizes solid phase whole-course fluidization continuous production, fully utilizes the heat of the product to heat the raw materials, has no leaching and evaporating concentration working section, has no discharge of waste gas, alkaline residue and waste water, has low energy consumption, and is high-purity anhydrous sodium sulfide.

Description

Sodium sulfide production system and process for gas-phase fluidization reduction of sodium sulfate
Technical Field
The invention relates to the field of production and preparation of sodium sulfide from sodium sulfate, in particular to a sodium sulfide production system and process for gas-phase fluidization reduction of sodium sulfate.
Background
At present, sodium sulfide is produced by a carbon reduction method, namely sodium sulfate and coal are placed into a high-temperature converter for calcination and reduction, a solid product is poured out and cooled after the reaction is finished, the product is cooled, then is dissolved by diluted alkali solution in a thermalization mode and is placed still, supernatant fluid is discharged and evaporated and concentrated, and finally a sheet-shaped industrial sodium sulfide product with the content of 60% is obtained. The chemical equation comprises the following reactions:
Na 2 SO 4 +2C=Na 2 S+2CO 2
Na 2 SO 4 +4C=Na 2 S+4CO
Na 2 SO 4 +4CO=Na 2 S+4CO 2
Na 2 SO 4 +4H 2 =Na 2 S+4H 2 O
the industrial production process adopts converter operation, can not realize continuous steady-state production, has complicated intermittent operation, low efficiency, high overall energy consumption and high cost; the reaction product needs leaching and evaporation purification, the operation flow is long, and the product contains crystal water; the production process can produce a large amount of solid caustic sludge and discharge a large amount of harmful hydrogen sulfide gas.
Chinese patent CN112010266A, CN110589775A, CN110589775B, CN 112028031A, CN107619025a all proposes a method for preparing sodium sulfide by gas reduction. The chemical equation comprises the following reactions:
Na 2 SO 4 +4H 2 =Na 2 S+4H 2 O
Na 2 SO 4 +4CO=Na 2 S+4CO 2
Na 2 SO 4 +CH 4 =Na 2 S+CO 2 +2H 2 O
the method needs to heat sodium sulfate to a molten state at first, then reducing gas is introduced, intermittent furnace pouring operation is needed in production, cooling and temperature reduction are needed before and after material entering and exiting, nitrogen replacement and material returning cleaning are needed, new production can be started by re-feeding, and although solid waste discharge is greatly improved, the whole production process is not greatly changed, and all defects of intermittent method operation, such as frequent operation steps, low yield efficiency, high energy consumption and the like still exist.
Disclosure of Invention
The invention provides a sodium sulfide production system for gas-phase fluidization reduction of sodium sulfate and a process thereof, and opens up a new process for recycling sodium sulfate byproducts in the chemical metallurgy industry, aiming at solving various problems of low intermittent production efficiency, large solid waste discharge of alkaline residues, large exhaust gas discharge, high overall energy consumption of the system and high labor intensity of workers in the existing sodium sulfide production technology.
A sodium sulfide production system for gas phase fluidization reduction of sodium sulfate and a technical scheme thereof are as follows:
a sodium sulfide production system for gas-phase fluidization reduction of sodium sulfate consists of a sodium sulfate fluidization heating unit, a reducing gas heating unit, a sodium sulfate fluidization reduction reaction unit, a sodium sulfide waste heat recovery unit and a cooling and product packaging unit; the method is characterized in that: the sodium sulfate fluidization heating unit can heat sodium sulfate to the reaction temperature, and is connected with the sodium sulfate fluidization reduction reaction unit; the reducing gas heating unit can heat the reducing gas to the reaction temperature, and is also connected with the sodium sulfate fluidization reduction reaction unit; the sodium sulfate fluidization reduction reaction unit generates sodium sulfide from sodium sulfate and reducing gas in the fluidized bed reactor, and the unit is connected with the sodium sulfide waste heat recovery unit; and the sodium sulfide waste heat recovery unit is used for cooling sodium sulfide and recovering high-grade waste heat, and is connected with the cooling and product packaging unit.
Preferably, the sodium sulfate fluidization heating unit comprises a sodium sulfate tank and a catalyst tank which are used for containing solid-phase materials, and a deoxidizing preheater which is communicated with the sodium sulfate tank and the catalyst tank, wherein the deoxidizing preheater is provided with two outlet ends of a solid phase and a gas phase, the outlet end of the solid phase is connected with the inlet end of a primary heater, the outlet end of the gas phase is communicated with a dead steam system, the primary heater is provided with two outlet ends of the solid phase and the gas phase, the outlet end of the solid phase is connected with the inlet end of a secondary heater, and the outlet end of the gas phase is introduced into the reducing gas heating unit; the second-stage heater is provided with two outlet ends of a solid phase and a gas phase, the outlet end of the solid phase is connected with a sodium sulfate fluidization reduction reaction unit, and the outlet end of the gas phase is introduced with a reducing gas heating unit; the reducing gas heating unit comprises a gas holder for storing reducing gas, and the outlet end of the gas holder is connected with the inlet end of the gas compressor; the outlet end of the gas compressor is connected with the reducing gas end of the preheater; the outlet end of the preheater is connected with the reducing gas end of the reducing gas-produced gas heat exchanger; the reducing gas-produced gas heat exchanger is provided with two gas phase inlet ends, the other produced gas end is communicated with the gas phase outlet end of the first-stage heater of the sodium sulfate fluidization heating unit, the reducing gas-produced gas heat exchanger is provided with two gas phase outlet ends, one reducing gas outlet end is connected with the reducing gas end of the reducing gas-produced gas heat exchanger, and the other gas phase outlet end is connected with a produced gas dephlegmator; the produced gas segregator is provided with two gas phase outlet ends, one gas phase outlet end is connected with a tail gas deacidification gas storage device, and the other liquid phase outlet end is connected with a condensation water tank; the gas phase outlet of the tail gas deacidification gas storage device is communicated with a gas holder; the reducing gas-outlet gas heat exchanger is provided with two gas phase inlet ends, the other outlet gas inlet end is communicated with the gas phase outlet end of the sodium sulfate fluidization heating unit secondary heater, the reducing gas-outlet gas heat exchanger is provided with two gas phase outlet ends, one reducing gas outlet end of the reducing gas-outlet gas heat exchanger is connected with the inlet end of the reducing gas heating furnace, the other outlet gas outlet end is connected with the outlet gas dephlegmator, the outlet gas dephlegmator is provided with two gas phase outlet ends, the gas phase outlet end of the outlet gas dephlegmator is connected with the inlet end of the gas-producing induced draft fan, and the other liquid phase outlet end of the outlet gas dephlegmator is connected with the condensation water tank; the liquid outlet of the condensation water tank is communicated with the preheater of the unit; the sodium sulfate fluidization reduction reaction unit comprises a first zone fluidized bed reactor and a second zone fluidized bed reactor, wherein the solid phase raw material outlet end of a secondary heater of the sodium sulfate fluidization heating unit is connected with the first zone fluidized bed reactor, a reducing gas heating furnace of the reducing gas heating unit is provided with at least two gas outlet ends which are respectively connected with the first zone fluidized bed reactor and the second zone fluidized bed reactor, the first zone fluidized bed reactor and the second zone fluidized bed reactor are mutually communicated, solid phase materials can be circularly exchanged in any reaction zone, the fluidized bed reactor is provided with a gas phase outlet, and the pipeline is communicated with the primary heater to convey the materials to the secondary heater; the second zone of fluidized bed reactor is provided with a solid phase outlet which is communicated with a sodium sulfide waste heat recovery unit; the sodium sulfide waste heat recovery unit comprises a sodium sulfide-produced gas heat exchanger, a steam superheater and a waste heat boiler; the sodium sulfide-produced gas heat exchanger is provided with a solid phase inlet end and a gas phase outlet end, wherein the solid phase inlet end is connected with the outlet end of a fluidized bed reactor in the second zone of the sodium sulfate fluidization reduction reaction unit, the gas phase inlet end is connected with the outlet end of a produced gas induced draft fan of the reducing gas heating unit, the solid phase outlet end is communicated with a steam superheater, and the gas phase outlet end is communicated with a pipeline for conveying materials from a deoxidizing preheater of the sodium sulfate fluidization heating unit to a primary heater; the steam superheater is provided with a solid phase inlet end and a gas phase inlet end, and is provided with a solid phase outlet end and a gas phase outlet end, the solid phase inlet end is connected with the sodium sulfide-produced gas heat exchanger and is provided with a solid phase outlet end, the gas phase inlet end is connected with a steam gas phase outlet end of the waste heat boiler, the solid phase outlet end is communicated with the waste heat boiler, and the gas phase outlet end is communicated with a sodium sulfate tank of the sodium sulfate fluidization heating unit and a pipeline for conveying mixed materials from the catalyst tank to the deoxidization preheater; the water-cooled wall tube nest of the waste heat boiler is provided with a desalted water inlet, the waste heat boiler further comprises a steam drum, a tube nest water collecting pipe is connected with the steam drum, a gas phase outlet end of the steam drum is connected with a gas phase inlet end of the steam superheater, and a solid phase outlet of the waste heat boiler is connected with a cooling and product packaging unit; the cooling and product packaging unit comprises an iron removal and packaging system, and the solid phase outlet end of the waste heat boiler is communicated with the iron removal and packaging system.
Preferably, the sodium sulfate tank, the catalyst tank, the deoxidizing preheater, the primary heater, the secondary heater, the first-zone fluidized bed reactor, the second-zone fluidized bed reactor, the gas holder, the reducing gas compressor, the blower, the reducing gas preheater, the reducing gas-produced gas heat exchanger, the reducing gas-outlet gas heat exchanger, the reducing gas heating furnace, the outlet gas dust remover, the outlet gas dephlegmator, the produced gas induced draft fan, the produced gas dust remover and the produced gas dephlegmator, the sodium sulfide-outlet gas heat exchanger, the steam superheater, the waste heat boiler, the condensed water tank, the tail gas deacidification gas equipment, and lock hoppers, discharge valves, slide valves and pressure and flow control components which are necessary for the solid phase material to enter and exit each equipment are adjusted through the control components, and the pressure among the equipment is controlled, so that fluidization steady-state operation of each equipment is maintained.
Preferably, the fluidized bed reactor comprises one or more of a boiling bed, a bubbling bed, a turbulent bed, a fast bed, a dilute phase bed, a dense phase bed and a riser; the number of the first zone fluidized bed reactors and the second zone fluidized bed reactors can be adjusted, and the first zone fluidized bed reactors and the second zone fluidized bed reactors are distributed in a multi-zone circulation mode.
Preferably, the inner wall of the fluidized bed reactor is provided with heat insulation, acid-base resistance and wear-resistant lining; a cyclone separator for gas-solid separation is arranged in the fluidized bed reactor; and the gas is discharged from a pipeline connected with the top after gas-solid separation in the fluidized bed reactor, and a solid phase discharge pipeline is arranged in a gas-solid separation sedimentation zone in the fluidized bed reactor.
A sodium sulfide production process for gas phase fluidization reduction of sodium sulfate, comprising the following steps:
(1) Sodium sulfate solid-phase particles and catalyst particles are respectively pumped into a sodium sulfate tank and a catalyst tank through a screw feeder or a pressurizing lock hopper type feeder, and the sodium sulfate tank and the catalyst tank are pressurized to ensure that the tank pressure is higher than the subsequent system pressure;
(2) The method comprises the steps of (1) taking superheated steam as conveying gas, conveying sodium sulfate and a catalyst from a buffer tank into a deoxidization preheater, removing oxygen in gaps among particles, heating raw material particles at the same time, and selecting the number of parallel connection of the deoxidization preheater according to equipment capacity, load, steam and sodium sulfate inlet feeding proportion, flow and flow rate; heating and then discharging the solid phase raw material to enter a primary heater; the deoxidizing preheater discharges the gas phase oxygen-containing exhaust steam out of the system;
(3) The high-temperature produced gas discharged by the sodium sulfide-produced gas heat exchanger enters a primary heater together with the solid phase raw material from the deoxidation preheater for mixed heating; the solid phase material separated by the primary heater enters the inlet of the secondary heater; the gas separated by the primary heater passes through the produced gas dust remover and then enters a reducing gas-produced gas heat exchanger; the produced gas discharged by the reducing gas-produced gas heat exchanger enters a produced gas dephlegmator, the separated gas phase tail gas enters deacidification equipment, the tail gas after deacidification and condensation enters a reducing gas cabinet for storage, or enters an inlet of a reducing gas compressor-blower to realize unreacted reducing gas circulation reaction, and the tail gas can also be discharged out of the system;
(4) The high-temperature outlet gas discharged from the fluidized bed reactor and the solid phase material from the primary heater enter the secondary heater for mixed heating; solid phase materials discharged by the secondary heater enter a first zone fluidized bed reactor; the gas separated by the secondary heater enters a reducing gas-outlet gas heat exchanger after passing through an outlet gas dust remover, and the reducing gas from the reducing gas-produced gas heat exchanger is heated; outlet gas discharged by the reducing gas-outlet gas heat exchanger enters an outlet gas dephlegmator, and separated gas phase produced gas enters a sodium sulfide-produced gas heat exchanger to recover high-temperature waste heat of sodium sulfide products;
(5) The reducing gas in the gas holder-storage tank is sent to the reducing gas preheater after being boosted by the reducing gas compressor-blower, then sent to the reducing gas-produced gas heat exchanger for heating, then sent to the reducing gas-outlet gas heat exchanger for heating, then sent to the reducing gas heating furnace for heating to the reaction temperature, the outlet temperature of the heating furnace is 0-1000 ℃, if the pressure of the externally supplied reducing gas is high, the turbine expansion of the reducing gas can be set to drive the reducing gas compressor-blower or the machine set gas supply system of the produced gas compressor to do work;
(6) The high-temperature reducing gas at the outlet of the reducing gas heating furnace is the conveying gas for conveying materials into the first zone fluidized bed reactor and the second zone fluidized bed reactor, and simultaneously, the solid phase materials extracted by the secondary cyclone heater are also conveyed into the first zone reactor; the solid phase material of the first zone reactor is extracted to the conveying gas of the second zone reactor;
(7) Solid phase materials extracted by the secondary cyclone heating separator enter a first zone fluidized bed reactor, reducing gas and solid phase particles form dense-phase and dilute-phase beds in different zones in the first zone fluidized bed reactor, and in a fluidization state, the gas phase and the solid phase fully contact and react, and the reaction interface between the particles and the gas is continuously updated; the top of the reactor is provided with a two-stage cyclone separator connected in series, gas phase and solid phase particles after reaction are separated, gas phase products are discharged from the top of the reactor, and solid phase products are discharged to a second-zone fluidized bed reactor through a material leg interface; part of high-temperature solid phase materials extracted from the second-zone fluidized bed reactor can be returned to the inlet of the first-zone fluidized bed reactor, so that on one hand, unreacted sodium sulfate in the second-stage fluidized bed is regulated to continue the circulating reaction, and on the other hand, the temperature of the solid phase bed layer of the first-stage fluidized bed reactor is maintained; the fluidized bed reactors may be configured as riser-type fluidized bed reactors, vertically arranged multi-stage fluidized bed reactors, multi-zone circulating reactors with expanded end dilute phase zones and dense phase zones combined, and combined fluidized bed reactors of the above type;
(8) Solid phase particles discharged from the first zone fluidized bed reactor and reducing gas enter the second zone fluidized bed reactor to continue to react, and a two-stage series cyclone separator is arranged at the top of the second zone fluidized bed reactor to separate gas phase products from solid phase product particles. The gas phase product separated by the cyclone separator arranged in the second-zone fluidized bed reactor and the produced gas of the first-zone fluidized bed enter a secondary heater to heat raw material sodium sulfate; the solid-phase product of the second-zone fluidized bed reactor is discharged from an interface at the material leg of the reactor, one part of the solid-phase product is returned to the first-zone fluidized bed reactor, and the other part of the solid-phase product is sent to a sodium sulfide-produced gas heat exchanger;
(9) Solid sodium sulfide products extracted from the sodium sulfide-produced gas heat exchanger firstly enter a steam superheater and then enter a waste heat boiler;
(10) Sodium sulfide products extracted by the waste heat boiler enter a sodium sulfide cooling and product packaging unit, sodium sulfide is continuously cooled by deoxidized water, nitrogen or circulating water, combustible reducing gas in a sodium sulfide gap is replaced by nitrogen, and finally the sodium sulfide enters a fluidized bed packaging system; if an iron catalyst is used, an electromagnetic iron removing device can be arranged before packaging to remove iron in the catalyst, and the iron can enter a catalyst tank to continue the cyclic reaction.
Preferably, the solid sodium sulfate in step (1) is sodium sulfate solid particles of technical grade purity; the catalyst comprises one or more of iron, iron oxide, other transition metal powder and other transition metal oxide; the reducing gas in the step (5) comprises one or more of hydrogen, methane and carbon monoxide; the molar ratio of the reducing gas entering the reactor in the step (7) to sodium sulfate is larger than the stoichiometric coefficient, excessive reducing gas is used for entering the reactor, the hydrogen excess coefficient is preferably larger than 1.1, and the excess coefficients of the three reducing gases are carbon monoxide > methane > hydrogen; the mass ratio of the catalyst to the sodium sulfate is more than 0.1 percent.
Preferably, the solid phase pipelines connected with the fluidized bed reactor in the step (6) are all provided with a loosening gas, and the loosening gas can be reducing gas or steam with higher pressure than the system or nitrogen with higher pressure than the system;
preferably, the reaction pressure of the first zone fluidized bed reactor is controlled to be 0.05-7.0MPa; the reaction temperature is controlled between 620 ℃ and 1000 ℃; the reaction pressure of the fluidized bed reactor in the second zone is controlled to be 0.05-7.0MPa; the temperature of the fluidized bed reactor is controlled below 1100 ℃; a heating or heat-taking tube bundle is arranged in the fluidized bed reactor; the fluidized bed reactor is provided with an excessive effective reducing gas molar excess coefficient larger than 1.1; in the fluidized bed reactor, the reaction time of sodium sulfate is adjusted according to the effective components of the reducing gas, the pressure of the reactor and the form of the reactor, and the reaction time is 0.5-2 hours.
Preferably, when the pressure of the externally supplied reducing gas is higher, the expansion turbine can be carried out by utilizing the pressure energy of the reducing gas, so as to drive the system to work by the reducing agent compressor-blower or the produced gas induced draft fan, and meanwhile, the flow velocity kinetic energy is provided for the reducing gas by utilizing the expansion of the reducing gas turbine; the fluidized bed reactor pressure is reduced by reducing the reducing gas pressure and the system overall pressure.
Preferably, the cooling of the sodium sulfide in the step (10) adopts a chilling flow, sodium sulfide solid and deionized water are mixed to prepare a solution product, and the solution product is subjected to standing precipitation to separate out the catalyst in the solution.
Compared with the prior art, the invention realizes continuous feeding and discharging production and can obtain high-purity sodium sulfide without crystal water; the leaching and evaporating concentration working sections of the traditional production method are omitted, and no alkaline residue and solid waste are produced in the production process; the gas phase of the reaction product is acid gas and water vapor, unreacted reducing gas can be recovered and circulated after treatment, and sodium sulfate and sodium sulfide materials carried by the gas phase can be recovered in the process condensate; the invention can design solid heater and fluidized bed reactor with various forms to realize continuous automatic control; the invention can be provided with two or more fluidized bed reactors to carry out series connection and parallel connection operation, has strong parameter controllability and is suitable for large-scale expansion production; because the gas phase and the solid phase are directly mixed and heated, and the heat exchange flow is scientifically matched, the whole energy consumption of the process is greatly reduced; compared with the traditional sodium sulfide sheet finished product, the product obtained by the invention is in a powder form, electromagnetic iron removing equipment can be additionally arranged to further improve the purity of the sodium sulfide product, and an efficient fluidization packaging system can be configured.
Drawings
FIG. 1 is a schematic diagram of the essential components of the technical scheme of the invention;
FIG. 2 is a schematic diagram of a process flow of the technical scheme of the invention;
fig. 3 is a schematic process flow diagram of examples 1 and 2 of the present invention.
Fig. 4 is a schematic process flow diagram of examples 2 and 3 of the present invention.
In the accompanying drawings
1: a sodium sulfate tank; 2: a catalyst tank; 3: a primary deoxygenation preheater; 4: a secondary deoxygenation preheater; 5: screw feeder/feed lock hopper; a stage 6 heater; 7: screw feeder/feed lock hopper; 8: a secondary heater; 9: a first zone fluidized bed reactor; 10: a second zone fluidized bed reactor; 11 reducing gas cabinet/tank: the method comprises the steps of carrying out a first treatment on the surface of the 12: a reducing gas compressor/blower; 13: a reducing gas preheater; 14: a reducing gas-produced gas heat exchanger; 15: a reducing gas-outlet gas heat exchanger; 16: a reducing gas heating furnace; 17: an outlet gas dust remover; 18: the outlet gas is separated into condensed gas; 19: a produced gas induced draft fan; 20: sodium sulfide-export gas heat exchanger, 21: a steam superheater; 22: a waste heat boiler; 23: a produced gas segregator; 24: a condensation water tank; 25: tail gas deacidification equipment; 26: a produced gas dust remover.
Detailed Description
In order that the present invention may be more readily understood, a more complete description of the invention will now be rendered by reference to specific embodiments that are illustrated, but not limiting, in a sodium sulfide production system and process for the gas phase fluidized reduction of sodium sulfate. It is apparent that the described embodiments are some, but not all embodiments of the present invention, and all other embodiments obtained by persons of ordinary skill in the art without making creative efforts based on the embodiments in the present invention are within the protection scope of the present invention.
Example 1
As shown in fig. 3, the gas phase reducing agent in the embodiment is provided by the synthesis gas of a methanol synthesis plant after being washed and purified by low-temperature methanol; the composition of the synthesis gas volume is 68.2% of hydrogen, 29.2% of carbon monoxide, 2.0% of carbon dioxide, 0.4% of nitrogen, 0.1% of argon and 0.1% of methane; the temperature of the synthesis gas is about 40 ℃ and the pressure is about 5.0MPa; the catalyst is ferric oxide, the raw material is industrial anhydrous sodium sulfate solid particles, and the sodium sulfate content is preferably more than 99%.
The sodium sulfide production system for gas-phase fluidization reduction of sodium sulfate consists of a sodium sulfate fluidization heating unit, a reducing gas heating unit, a sodium sulfate fluidization reduction reaction unit, a sodium sulfide waste heat recovery unit and a cooling and product packaging unit; the sodium sulfate fluidization heating unit can heat sodium sulfate to the reaction temperature, and is connected with the sodium sulfate fluidization reduction reaction unit; the reducing gas heating unit can heat the reducing gas to the reaction temperature, and is also connected with the sodium sulfate fluidization reduction reaction unit; the sodium sulfate fluidization reduction reaction unit generates sodium sulfide from sodium sulfate and reducing gas in the fluidized bed reactor, and the unit is connected with the sodium sulfide waste heat recovery unit; and the sodium sulfide waste heat recovery unit is used for cooling sodium sulfide and recovering high-grade waste heat, and is connected with the cooling and product packaging unit.
A sodium sulfate tank, a catalyst tank, a deoxidizing preheater, a primary heater, a secondary heater, a first fluidized bed reactor, a second fluidized bed reactor, a reducing gas cabinet/storage tank, a reducing gas compressor/blower, a reducing gas preheater, a reducing gas-produced gas heat exchanger, a reducing gas-outlet gas heat exchanger, a reducing gas heating furnace, an outlet gas dust remover, an outlet gas dephlegmator, a produced gas induced draft fan, a produced gas dust remover, a produced gas dephlegmator, a sodium sulfide-outlet gas heat exchanger, a steam superheater, a waste heat boiler, a condensed water tank, tail gas deacidification gas and other devices, and lock hoppers, discharge valves, slide valves, pressure and flow control parts necessary for solid phase materials to enter and exit the devices; the solid phase flow and the gas phase flow are regulated by the control component, the pressure among the devices is controlled, and the fluidization steady-state operation of each device is maintained.
The specific operation steps are as follows:
(1) Pumping sodium sulfate solid particles and catalyst particles into respective buffer tanks 1 and 2 through a screw feeder or a pressurizing lock hopper feeder, wherein the pressure of the buffer tank for solid raw materials is higher than the pressure of a subsequent system in order to ensure that the solid raw materials are fed into a reaction system;
(2) The superheated steam is used as conveying gas, sodium sulfate and catalyst are sent into a primary deoxidation preheater 3 from a tank to remove oxygen in gaps among particles, raw material particles are heated at the same time, the number of parallel connection of the deoxidation preheaters is selected according to equipment capacity, load, steam and sodium sulfate inlet feeding proportion, flow and flow rate, and the secondary deoxidation preheaters 4 are also arranged in the embodiment; the solid phase raw material discharged after heating enters a primary heater 6 through a feeding lock hopper 5; the gas phase material discharged by the deoxidizing preheater is oxygen-containing exhaust steam, so that the oxygen-containing exhaust steam is prevented from corroding heat exchange equipment and is not suitable to be used as a heat exchange medium of reducing gas;
(3) The high-temperature produced gas discharged by the sodium sulfide-produced gas heat exchanger 20 enters the primary heater 6 together with the raw material solids from the deoxidation preheater 4 for mixed heating; the solid phase separated by the primary heater 6 enters the inlet of the secondary heater 8 through the feeding lock hopper 7; the gas phase separated by the primary heater 6 passes through the produced gas dust remover 26 and then enters the reducing gas-produced gas heat exchanger 14; the produced gas discharged from the reducing gas-produced gas heat exchanger 14 enters a produced gas dephlegmator 23, the separated gas phase tail gas enters an acid gas removal device 25, the tail gas after deacidification and condensation enters a reducing gas cabinet 11 or enters an inlet of a reducing gas compressor/blower 12 to realize unreacted reducing gas circulation reaction, and the tail gas can be sent out to other units for treatment; the produced gas dephlegmator 23 is communicated with a condensate tank 24;
(4) The high-temperature outlet gas discharged from the fluidized bed reactor 9 enters the secondary heater 8 together with the raw material solids from the primary heater 6 for mixed heating; the solid phase raw material discharged from the secondary heater 8 enters a first zone fluidized bed reactor 9; the gas phase separated by the secondary heater 8 enters the reducing gas-outlet gas heat exchanger 15 after passing through the outlet gas dust remover 17, and the reducing gas from the reducing gas-produced gas heat exchanger is heated; outlet gas discharged by the reducing gas-outlet gas heat exchanger 15 enters an outlet gas dephlegmator 18, and separated gas phase produced gas enters a sodium sulfide-produced gas heat exchanger 20 through a produced gas induced draft fan 19 to recover high-temperature waste heat of sodium sulfide products; the outlet gas dephlegmator 18 is in communication with a condensate tank 24;
(5) If the pressure of the externally supplied reducing gas is high, a unit gas supply system for driving a reducing gas compressor/blower or a produced gas induced draft fan to do work by the expansion of a reducing gas turbine can be arranged: the externally supplied synthetic gas enters a turbine expander, the expander drives a gas compressor/blower or a produced gas induced draft fan to do work, and the decompressed and expanded synthetic gas enters a reducing gas cabinet 11. The reducing gas is sent to a reducing gas preheater 13 after being boosted by a reducing gas compressor/blower 12, then sent to a reducing gas-produced gas heat exchanger 14 for heating, then sent to a reducing gas-outlet gas heat exchanger 15 for heating, then sent to a reducing gas heating furnace 16 for heating to the reaction temperature, the outlet temperature of the heating furnace is 620-1000 ℃, the control range is 620-680 ℃, and the excess coefficient of the reducing gas is 1.1-1.2;
(6) The high-temperature reducing gas at the outlet of the reducing gas heating furnace 16 is respectively sent into the first zone fluidized bed reactor 9 and the second zone fluidized bed reactor 10, and simultaneously is the conveying gas of the solid extracted by the secondary cyclone heater and entering the first zone fluidized bed reactor 9; the gas is also the loose conveying gas from the solid phase of the first zone fluidized bed reactor to the second zone fluidized bed reactor; the temperature control range of the reducing gas entering the first zone fluidized bed reactor from the heating furnace is 620-640 ℃, the temperature control range of the reducing gas entering the second zone fluidized bed reactor from the heating furnace is 640-680 ℃, and the temperature of the reducing gas entering the second zone fluidized bed reactor is always kept higher than the temperature entering the first zone fluidized bed reactor; the first zone of fluidized bed reactor maintains a dense phase fluidized bed, and the second zone of fluidized bed reactor maintains a dilute phase fluidized bed;
(7) The solid extracted by the secondary cyclone heating separator enters a first zone fluidized bed reactor, reducing gas and solid particles form dense-phase and dilute-phase beds in different zones in the first zone fluidized bed reactor, and in a fluidization state, the gas phase and the solid phase are fully contacted and reacted, and the reaction interface between the particles and the gas is continuously updated; the top of the reactor is provided with a two-stage cyclone separator connected in series, the reacted gas phase and solid phase particles are separated, the gas phase is discharged from the top of the reactor, and the solid phase is discharged to the fluidized bed reactor in the second zone through a connecting port at a dipleg; the pressure of the reactor is set to be 0.05-2MPa, and the preferable pressure parameter is 0.05-0.5MPa; part of high-temperature solids extracted from the second-zone fluidized bed reactor can be returned to the inlet of the first-zone fluidized bed reactor, so that on one hand, unreacted sodium sulfate in the second-stage fluidized bed is regulated to continue the circulating reaction, and on the other hand, the solid-phase bed temperature of the first-zone fluidized bed reactor is maintained; the fluidized bed reactors may be configured as riser-type fluidized bed reactors, vertically arranged multi-stage fluidized bed reactors, multi-zone circulating reactors with expanded end dilute phase zones and dense phase zones combined, and combined fluidized bed reactors of the above type;
(8) Solid particles discharged from the first zone fluidized bed reactor and reducing gas enter the second zone fluidized bed reactor to continue to react, and a two-stage series cyclone separator is arranged at the top of the second zone fluidized bed reactor to separate gas phase and solid phase particles after reaction. The gas phase separated by the cyclone separator arranged in the second-zone fluidized bed reactor and the produced gas of the first-zone fluidized bed enter a second-zone heater together to heat the raw material sodium sulfate; the solid phase of the second-zone fluidized bed reactor is discharged from an interface at the material leg of the reactor, one part of the solid phase is returned to the first-zone reactor, and the other part of the solid phase is sent to the sodium sulfide-produced gas heat exchanger 20;
(9) The solid-phase sodium sulfide product extracted from the sodium sulfide-produced gas heat exchanger 20 firstly enters the steam superheater 21 and then enters the waste heat boiler 22, desalted water is injected into a water-cooled wall tube array of the waste heat boiler 22, a water collecting tube of the tube array of the waste heat boiler is connected with a steam drum, and an outlet of the steam drum is connected with an inlet of the superheated steam heat exchanger 21; the outlet of the steam superheating heat exchanger 21 is connected with the sodium sulfate deoxidizing preheater 3;
(10) Sodium sulfide products extracted by the waste heat boiler 22 enter a sodium sulfide cooling and product packaging unit, sodium sulfide is continuously cooled by deoxidized water, nitrogen or circulating water, combustible reducing gas in a sodium sulfide gap is replaced by nitrogen, and finally the sodium sulfide enters a fluidized bed packaging system; if an iron catalyst is used, an electromagnetic iron removing device can be arranged before packaging to remove iron in the catalyst, and the iron can enter a catalyst tank to continue the cyclic reaction;
Example 2
As shown in FIG. 3, the gas phase reducing agent in this example is a synthesis gas which is purified by low temperature methanol washing in a certain ammonia plant, and the volume composition of the gas phase reducing agent is 97% of hydrogen, 2% of carbon monoxide, 20ppm of carbon dioxide, 0.4% of nitrogen, 0.1% of argon, 0.5% of methane, and the gas temperature is 40 ℃ and the pressure is 5.0MPa; the catalyst is ferric oxide, the raw materials are industrial anhydrous sodium sulfate solid particles, the sodium sulfate content is more than 99%, and the pressure is 5.0MPa;
example 2 the procedure was the same as in example 1 except that the reducing gas composition was different from that of example 1; it should be noted that the reducing gas excess coefficient, the reaction time and the solid-phase product return circulation amount of the final reactor in example 2 can be reduced appropriately;
example 3
As shown in fig. 4, the present example is different from example 2 in that the gas-phase reducing agent is hydrogen gas supplied from electrolyzed water, the volume composition thereof is 100% hydrogen gas, the temperature is 25 ℃, the pressure is 0.1MPa, and the reducing gas thereof may be referred to as hydrogen gas; the catalyst is ferric oxide, and the raw materials are industrial anhydrous sodium sulfate solid particles; sodium sulfate content is greater than 99%;
example 3 differs from example 2 in the implementation: the system and process described in example 3 does not provide tail gas deacidification apparatus 25; the system and process described in example 3 uses no turbo-expander set and flow path due to low hydrogen pressure; the rest is the same as in example 2
Example 4
As shown in fig. 3, this example differs from example 2 in that the gas phase reducing agent is natural gas, the volume composition of which is 98% methane, the temperature is 25 ℃, and the pressure is 0.1MPa. This example also differs from example 2 in that the 16-reducing gas heating furnace was changed to a methane reforming hydrogen production unit.
Under the condition of the same reaction temperature and pressure, the reaction speeds of the hydrogen, the carbon monoxide and the methane are respectively different from that of the sodium sulfate, and the reaction activity is that the hydrogen is more than the methane and more than the carbon monoxide from large to small, so that the reaction speed can be increased by adopting the reducing gas with large hydrogen component proportion; according to the chemical equation of hydrogen and carbon monoxide for reducing sodium sulfate, the reaction pressure is increased so as not to accelerate the process of counter balance, and therefore, for reducing gases with large hydrogen and an oxidizing component, low-pressure operation is preferably adopted. The system pressure is reduced, the fluidization kinetic energy requirement is reduced, the manufacturing difficulty of various equipment is reduced, and the material risk of hydrogen etching and hydrogen embrittlement is reduced. The reaction speed of three reducing gases and sodium sulfate can be accelerated by increasing the reaction temperature. The product sodium sulfide and reactant sodium sulfate form a mixed component system with the lowest eutectic point when at a reaction temperature of 650±10 ℃. The dense bed zone in the reactor is preferably subjected to low-temperature reaction with the control temperature of less than 640 ℃, and the dilute bed zone is preferably subjected to reaction with the control temperature of more than 640 ℃ to prevent the formation of droplets in the dense bed after the solid phase particles are melted; meanwhile, solid particles in the dilute phase region form eutectic liquid drops, and because the turbulence field in the dilute phase region is aggravated, the updating of the gas-solid contact surface can be quickened, the diffusion control speed of a particle reaction model is improved, and the proceeding of a reduction reaction can be quickened;
The fluidized bed reactor for vapor phase reduction of sodium sulfate of the present invention may be any type of fluidized bed reactor including, but not limited to, ebullated bed, bubbling bed, turbulent bed, fast bed, dilute phase bed, dense phase bed, riser, or any combination thereof; the fluidized bed reactor can be designed as a multizone circulating fluidized bed reactor; the fluidized bed reactor is named as a first zone and a second zone in the system and the process, and is only used for expressing that the fluidized bed reactor can realize the circulation function of returning high-temperature sodium sulfide products and unreacted sodium sulfate products to a raw material inlet of the reactor, but not two specific reactors, and the number and the structural type of the fluidized bed reactor are set according to the characteristics of the reactor and the treatment scale. The inner wall of the reactor is provided with heat insulation, acid-alkali resistance and wear-resistant lining; the fluidized bed reactor is connected with a high-temperature reducing gas pipeline and heating equipment thereof, the fluidized bed reactor is connected with a solid phase discharge pipeline of the highest-level sodium sulfate heater, and a cyclone separator for gas-solid separation is arranged in the fluidized bed reactor; the gas phase is discharged from a pipeline connected with the top after gas-solid separation in the fluidized bed reactor, and a solid phase discharge pipeline is arranged in a gas-solid separation sedimentation zone in the fluidized bed reactor; the solid phase pipelines connected with the reactor are all provided with a loosening gas, and the loosening gas can be reducing gas, steam with higher pressure than the system or nitrogen with higher pressure than the pipeline; the reaction pressure of the fluidized bed reactor is controlled to be 0.05-6.5MPa, preferably the reaction pressure is controlled to be 0.1-2.5MPa; the temperature of the fluidized bed reactor is controlled below 1100 ℃, and the reaction temperature is preferably controlled between 620 and 680 ℃; it is also preferably characterized in that: according to the composition of the reducing gas and the process requirement, a heating or heat-collecting tube bundle can be arranged in the fluidized bed to adjust the temperature in the reactor; in the fluidized bed reactor, the proportioning characteristics of raw materials are as follows: the entering proportion of the effective reducing gas and the raw material sodium sulfate is required to be provided with excessive effective reducing gas according to the stoichiometric relation; preferably characterized by an effective reducing gas molar excess coefficient greater than 1.5; it is also characterized in that: in the fluidized bed reactor, the reaction time of sodium sulfate is adjusted according to the effective components of the reducing gas, the pressure of the reactor and the form of the reactor. The reaction time is 0-2h; preferably the reaction time is 0.5-1.5h;
The invention relates to a raw material sodium sulfate fluidization heating unit, which is characterized in that sodium sulfate raw material solid and high-temperature gas are mixed and heated in equipment with a gas-solid separation function and separated again, wherein the equipment can be a cyclone separator or fluidization heating separation equipment with the gas-solid separation function, such as a boiling bed, a bubbling bed, a turbulent bed, a rapid bed, a dilute phase bed, a dense phase bed, a riser pipe or equipment with any combination of the above; the sodium sulfate fluidization heating unit comprises a sodium sulfate tank, a catalyst iron tank, a deoxidizing preheater, sodium sulfate heaters at all levels and a dust remover; the sodium sulfate tank is communicated with the catalyst tank and is connected with the inlet of the deoxidizing preheater, the solid-phase material outlet of the deoxidizing preheater is connected with the inlet of the lowest-stage temperature heater, and the solid-phase material outlet of the lowest-stage heater is connected with the solid-phase material inlet of the lower-stage heater. The solid-phase material outlet of the final-stage heater is connected with the inlet of the fluidized bed reactor; setting the heating sequence of sodium sulfate from low to high, and finally heating the sodium sulfate to 500-1000 ℃ to enter a reactor; the preferred temperature is 500-650 ℃. The high-temperature gas for heating the sodium sulfate raw material can be high-temperature superheated steam, high-temperature gas after combustion of combustible gas and gas produced by the fluidized bed reactor. Heating raw material sodium sulfate flow sequence: the sodium sulfate material is preheated by nitrogen or steam to displace oxygen in the gaps of sodium sulfate particles, and then heated by combustible high-temperature gas. The combustible high-temperature gas is the outlet gas or the produced gas of the fluidized bed reactor. And after being discharged from the fluidized bed reactor, the outlet gas of the fluidized bed reactor enters a highest-grade sodium sulfate heater of a sodium sulfate heating unit, and enters a reducing gas-outlet gas heat exchanger of a reducing gas heating unit to provide heat after dust removal. The gas discharged from the outlet gas dephlegmator is the produced gas of the system, the produced gas is pressurized by a produced gas induced draft fan after being discharged from the outlet gas dephlegmator, and is heated by a sodium sulfide-produced gas heat exchanger, then enters a heater lower than the grade of the outlet gas heater in the sodium sulfate heating unit to provide heat, and enters a reducing gas-produced gas heat exchanger in the reducing gas heating unit to provide heat after the dust removal of the outlet gas of the sodium sulfate heater, and the gas discharged from the produced gas dephlegmator is the tail gas of the system.
In the reducing gas heating unit, the outlet of a reducing gas cabinet or a storage tank is connected with the inlet of a reducing gas compressor or a blower; the outlet of the reducing gas compressor or the blower is connected with the inlet of the reducing gas preheater; the outlet of the reducing gas preheater is connected with the inlet of the reducing gas-produced gas heat exchanger; the connecting outlet of the reducing gas-produced gas heat exchanger is connected with the inlet of the reducing gas-outlet gas heat exchanger; the outlet of the reducing gas-outlet gas heat exchanger is connected with the inlet of the reducing gas heating furnace; the outlet of the reducing gas heating furnace is connected with the fluidized bed reactor and can provide loosening gas required by the process; the flow characteristics of the reducing gas heating unit are as follows: the system and the process of the gas holder are provided with a reducing gas buffer container which can be a gas holder or other storage tank pressure container, and the buffer container is sent to subsequent reducing gas heating equipment after being pressurized by a reducing gas compressor or an air blower. The heat source medium of the reducing gas heating device can be steam, the outlet gas of the fluidized bed reactor, the produced gas, the solid phase discharge of the fluidized bed reactor, a reducing gas heating furnace and other heat sources, the device with the highest temperature for heating the reducing gas is an industrial heating furnace, and the reducing gas is in a furnace tube; the reducing gas heating unit is preferably characterized in that reducing gas is heated step by a heat exchanger and a heating furnace of different grade heat sources and then enters a fluidized bed reactor, the temperature of the reducing gas entering the fluidized bed reactor is 0-1100 ℃, and the preferable temperature is controlled at 600-680 ℃; the reducing gas heating scheme is also preferably characterized by: the outlet gas and the produced gas materials firstly enter a sodium sulfate heating unit to provide a heat source, and then the separated gas is discharged from a low-level heater of the sodium sulfate raw material heating process and enters a reducing gas heating unit. The gas heats the reducing gas and then enters a condenser to separate condensate and non-condensable gas; non-condensable gas of the outlet gas with high temperature and pressure grade is produced gas, and enters a sodium sulfide-produced gas heat exchanger to recover high-grade sodium sulfide heat. The noncondensable gas of the produced gas with low temperature and pressure grade is tail gas, and enters the reducing gas buffer container after entering the deacidification gas equipment, so that unreacted reducing gas in the tail gas is recycled. The tail gas deacidification gas in the system and the process can be a sodium hydroxide absorption washing process, or a deacidification gas unit is not needed, and the tail gas is sent out of the system to other units for treatment, for example, the tail gas can be sent to units for low-temperature methanol washing, sodium hydroxide alkaline washing, organic amine absorption and the like for treatment and then is recovered.
The sodium sulfide waste heat recovery unit is used for cooling the sodium sulfide, and the medium for cooling the sodium sulfide can be produced gas, reducing gas, steam, desalted water, circulating water and other streams with the temperature lower than that of the cooled sodium sulfide; the sodium sulfide interface of the sodium sulfide waste heat recovery unit, which is used for ending the reaction and leaving the fluidized bed reactor, is connected with the inlet of the produced gas-sodium sulfide heat exchanger; the outlet of the produced gas-sodium sulfide heat exchanger is connected with the inlet of the steam superheater; the outlet of the steam superheater is connected with the inlet of the waste heat boiler; the outlet of the waste heat boiler is connected with subsequent sodium sulfide cooling equipment; after the sodium sulfide is discharged out of the fluidized bed reactor, the sodium sulfide is cooled by the produced gas after the outlet gas from heating the reducing gas is separated and condensed; then enters a steam superheater to be cooled by steam from a waste heat boiler, then enters the waste heat boiler to produce saturated steam, and desalted water is injected into the tube side of the waste heat boiler. A steam inlet in the superheated steam tube side is connected with a waste heat boiler drum outlet; the produced superheated steam pipeline is connected with an inlet of a sodium sulfide deoxidizing preheater in the sodium sulfide heating unit; the product sodium sulfide in the system and the process is discharged out of the waste heat boiler and enters an electromagnetic iron removing and packaging system, the iron removing function can be designed into a device with a fluidized bed and electromagnetic iron removing separating function, and the sodium sulfide packaging system can be set into a fluidized bed process.
If the pressure of the externally supplied reducing gas is higher, the expansion turbine can be carried out by utilizing the pressure energy of the reducing gas to drive the system to do work by the reducing agent compressor/blower or the produced gas induced draft fan. The fluidized bed reactor pressure is reduced by reducing the reducing gas pressure while providing flow rate kinetic energy to the reducing gas using the reducing gas turbine expansion.
Although the invention provides a secondary sodium sulfate heater, a secondary fluidized bed reactor, a primary deoxidizing preheater and a primary gas-gas heat exchanger, the number of stages, the number and the heat exchange flow of the reactor and the heat exchange equipment are changed without causing new and inventive changes of the method, a person of ordinary skill in the art will understand that any changes in form and details which do not exceed the scope of protection of the claims are all within the scope of the invention.

Claims (10)

1. A sodium sulfide production system for gas-phase fluidization reduction of sodium sulfate consists of a sodium sulfate fluidization heating unit, a reducing gas heating unit, a sodium sulfate fluidization reduction reaction unit, a sodium sulfide waste heat recovery unit and a cooling and product packaging unit; the method is characterized in that:
the sodium sulfate fluidization heating unit can heat sodium sulfate to the reaction temperature, and is connected with the sodium sulfate fluidization reduction reaction unit; the device comprises a sodium sulfate tank for storing solid-phase materials and a catalyst tank, and a deoxidizing preheater communicated with the sodium sulfate tank and the catalyst tank, wherein the deoxidizing preheater is provided with two outlet ends of a solid phase and a gas phase, the outlet end of the solid phase is connected with the inlet end of a primary heater, the outlet end of the gas phase is communicated with a dead steam system, the primary heater is provided with two outlet ends of the solid phase and the gas phase, the outlet end of the solid phase is connected with the inlet end of a secondary heater, and the outlet end of the gas phase is introduced into a reducing gas heating unit; the second-stage heater is provided with two outlet ends of a solid phase and a gas phase, the outlet end of the solid phase is connected with a sodium sulfate fluidization reduction reaction unit, and the outlet end of the gas phase is introduced with a reducing gas heating unit;
The reducing gas heating unit can heat the reducing gas to the reaction temperature, and is also connected with the sodium sulfate fluidization reduction reaction unit; the device comprises a gas holder for storing reducing gas, wherein the outlet end of the gas holder is connected with the inlet end of a gas compressor; the outlet end of the gas compressor is connected with the reducing gas end of the preheater; the outlet end of the preheater is connected with the reducing gas end of the reducing gas-produced gas heat exchanger; the reducing gas-produced gas heat exchanger is provided with two gas phase inlet ends, the other produced gas end is communicated with the gas phase outlet end of the first-stage heater of the sodium sulfate fluidization heating unit, the reducing gas-produced gas heat exchanger is provided with two gas phase outlet ends, one reducing gas outlet end is connected with the reducing gas end of the reducing gas-produced gas heat exchanger, and the other gas phase outlet end is connected with a produced gas dephlegmator; the produced gas segregator is provided with two gas phase outlet ends, one gas phase outlet end is connected with a tail gas deacidification gas storage device, and the other liquid phase outlet end is connected with a condensation water tank; the gas phase outlet of the tail gas deacidification gas storage device is communicated with a gas holder; the reducing gas-outlet gas heat exchanger is provided with two gas phase inlet ends, the other outlet gas inlet end is communicated with the gas phase outlet end of the sodium sulfate fluidization heating unit secondary heater, the reducing gas-outlet gas heat exchanger is provided with two gas phase outlet ends, one reducing gas outlet end of the reducing gas-outlet gas heat exchanger is connected with the inlet end of the reducing gas heating furnace, the other outlet gas outlet end is connected with the outlet gas dephlegmator, the outlet gas dephlegmator is provided with two gas phase outlet ends, the gas phase outlet end of the outlet gas dephlegmator is connected with the inlet end of the gas-producing induced draft fan, and the other liquid phase outlet end of the outlet gas dephlegmator is connected with the condensation water tank; the liquid outlet of the condensation water tank is communicated with the preheater of the unit;
The sodium sulfate fluidization reduction reaction unit generates sodium sulfide from sodium sulfate and reducing gas in the fluidized bed reactor, and the unit is connected with the sodium sulfide waste heat recovery unit; the method comprises a first zone fluidized bed reactor and a second zone fluidized bed reactor, wherein a solid phase raw material outlet end of a secondary heater of a sodium sulfate fluidization heating unit is connected with the first zone fluidized bed reactor, a reducing gas heating furnace of a reducing gas heating unit is provided with at least two gas outlet ends which are respectively connected with the first zone fluidized bed reactor and the second zone fluidized bed reactor, the first zone fluidized bed reactor and the second zone fluidized bed reactor are communicated with each other, solid phase materials can be circularly exchanged in any reaction zone, the fluidized bed reactor is provided with a gas phase outlet, and the gas phase outlet is communicated with a pipeline for conveying materials to the secondary heater by the primary heater; the second zone of fluidized bed reactor is provided with a solid phase outlet which is communicated with a sodium sulfide waste heat recovery unit;
the sodium sulfide waste heat recovery unit is used for cooling sodium sulfide and recovering high-grade waste heat, and is connected with the cooling and product packaging unit; the device comprises a sodium sulfide-produced gas heat exchanger, a steam superheater and a waste heat boiler; the sodium sulfide-produced gas heat exchanger is provided with a solid phase inlet end and a gas phase outlet end, wherein the solid phase inlet end is connected with the outlet end of a fluidized bed reactor in the second zone of the sodium sulfate fluidization reduction reaction unit, the gas phase inlet end is connected with the outlet end of a produced gas induced draft fan of the reducing gas heating unit, the solid phase outlet end is communicated with a steam superheater, and the gas phase outlet end is communicated with a pipeline for conveying materials from a deoxidizing preheater of the sodium sulfate fluidization heating unit to a primary heater; the steam superheater is provided with a solid phase inlet end and a gas phase inlet end, and is provided with a solid phase outlet end and a gas phase outlet end, the solid phase inlet end is connected with the sodium sulfide-produced gas heat exchanger and is provided with a solid phase outlet end, the gas phase inlet end is connected with a steam gas phase outlet end of the waste heat boiler, the solid phase outlet end is communicated with the waste heat boiler, and the gas phase outlet end is communicated with a sodium sulfate tank of the sodium sulfate fluidization heating unit and a pipeline for conveying mixed materials from the catalyst tank to the deoxidization preheater; the water-cooled wall tube nest of the waste heat boiler is provided with a desalted water inlet, the waste heat boiler further comprises a steam drum, a tube nest water collecting pipe is connected with the steam drum, a gas phase outlet end of the steam drum is connected with a gas phase inlet end of the steam superheater, and a solid phase outlet of the waste heat boiler is connected with a cooling and product packaging unit;
The cooling and product packaging unit comprises an iron removal and packaging system, and the solid phase outlet end of the waste heat boiler is communicated with the iron removal and packaging system.
2. The sodium sulfide production system of claim 1, wherein: the device comprises a sodium sulfate tank, a catalyst tank, a deoxidizing preheater, a primary heater, a secondary heater, a first-zone fluidized bed reactor, a second-zone fluidized bed reactor, a gas holder, a reducing gas compressor, a blower, a reducing gas preheater, a reducing gas-produced gas heat exchanger, a reducing gas-outlet gas heat exchanger, a reducing gas heating furnace, an outlet gas dust remover, an outlet gas dephlegmator, a produced gas induced draft fan, a produced gas dust remover, a produced gas dephlegmator, a sodium sulfide-outlet gas heat exchanger, a steam superheater, a waste heat boiler, a condensation water tank, tail gas deacidification equipment, and lock hoppers, discharge valves, slide valves, pressure and flow control components which are necessary for solid phase materials to enter and exit each equipment, wherein the pressure among the equipment is controlled by the control components, so that fluidization steady-state operation of each equipment is maintained.
3. The sodium sulfide production system of claim 1, wherein: the fluidized bed reactor comprises one or more of a boiling bed, a bubbling bed, a turbulent bed, a rapid bed, a dilute phase bed and a dense phase bed; the number of the first zone fluidized bed reactors and the second zone fluidized bed reactors can be adjusted, and the first zone fluidized bed reactors and the second zone fluidized bed reactors are distributed in a multi-zone circulation mode.
4. The sodium sulfide production system of claim 2, wherein; the inner wall of the fluidized bed reactor is provided with a heat insulation, acid-alkali resistance and wear-resistant lining; a cyclone separator for gas-solid separation is arranged in the fluidized bed reactor; and the gas is discharged from a pipeline connected with the top after gas-solid separation in the fluidized bed reactor, and a solid phase discharge pipeline is arranged in a gas-solid separation sedimentation zone in the fluidized bed reactor.
5. The process for producing sodium sulfide by gas-phase fluidization reduction of sodium sulfate is characterized by comprising the following steps of:
(1) Sodium sulfate solid-phase particles and catalyst particles are respectively pumped into a sodium sulfate tank and a catalyst tank through a screw feeder or a pressurizing lock hopper type feeder, and the sodium sulfate tank and the catalyst tank are pressurized to ensure that the tank pressure is higher than the subsequent system pressure;
(2) The method comprises the steps of (1) taking superheated steam as conveying gas, conveying sodium sulfate and a catalyst from a buffer tank into a deoxidization preheater, removing oxygen in gaps among particles, heating raw material particles at the same time, and selecting the number of parallel connection of the deoxidization preheater according to equipment capacity, load, steam and sodium sulfate inlet feeding proportion, flow and flow rate; heating and then discharging the solid phase raw material to enter a primary heater; the deoxidizing preheater discharges the gas phase oxygen-containing exhaust steam out of the system;
(3) The high-temperature produced gas discharged by the sodium sulfide-produced gas heat exchanger enters a primary heater together with the solid phase raw material from the deoxidation preheater for mixed heating; the solid phase material separated by the primary heater enters the inlet of the secondary heater; the gas separated by the primary heater passes through the produced gas dust remover and then enters a reducing gas-produced gas heat exchanger; the produced gas discharged by the reducing gas-produced gas heat exchanger enters a produced gas dephlegmator, separated gas phase tail gas enters deacidification equipment, and the tail gas after deacidification and condensation enters a reducing gas cabinet for storage or enters an inlet of a reducing gas compressor-blower to realize unreacted reducing gas circulation reaction;
(4) The high-temperature outlet gas discharged from the fluidized bed reactor and the solid phase material from the primary heater enter the secondary heater for mixed heating; solid phase materials discharged by the secondary heater enter a first zone fluidized bed reactor; the gas separated by the secondary heater enters a reducing gas-outlet gas heat exchanger after passing through an outlet gas dust remover, and the reducing gas from the reducing gas-produced gas heat exchanger is heated; outlet gas discharged by the reducing gas-outlet gas heat exchanger enters an outlet gas dephlegmator, and separated gas phase produced gas enters a sodium sulfide-produced gas heat exchanger to recover high-temperature waste heat of sodium sulfide products;
(5) The reducing gas in the gas holder-storage tank is sent to the reducing gas preheater after being boosted by the reducing gas compressor-blower, then sent to the reducing gas-produced gas heat exchanger for heating, then sent to the reducing gas-outlet gas heat exchanger for heating, then sent to the reducing gas heating furnace for heating to the reaction temperature, the outlet temperature of the heating furnace is 0-1000 ℃, the pressure of the externally supplied reducing gas is high, and the reducing gas turbine expansion is arranged to drive the reducing gas compressor-blower or the machine set gas supply system of the produced gas compressor to do work;
(6) The high-temperature reducing gas at the outlet of the reducing gas heating furnace is the conveying gas for conveying materials into the first zone fluidized bed reactor and the second zone fluidized bed reactor, and simultaneously, the solid phase materials extracted by the secondary cyclone heater are also conveyed into the first zone reactor; the solid phase material of the first zone reactor is extracted to the conveying gas of the second zone reactor;
(7) Solid phase materials extracted by the secondary cyclone heating separator enter a first zone fluidized bed reactor, reducing gas and solid phase particles form dense-phase and dilute-phase beds in different zones in the first zone fluidized bed reactor, and in a fluidization state, the gas phase and the solid phase fully contact and react, and the reaction interface between the particles and the gas is continuously updated; the top of the reactor is provided with a two-stage cyclone separator connected in series, gas phase and solid phase particles after reaction are separated, gas phase products are discharged from the top of the reactor, and solid phase products are discharged to a second-zone fluidized bed reactor through a material leg interface; part of high-temperature solid phase materials extracted from the second-zone fluidized bed reactor are returned to the inlet of the first-zone fluidized bed reactor, so that on one hand, unreacted sodium sulfate in the second-stage fluidized bed is regulated to continue the circulating reaction, and on the other hand, the temperature of the solid phase bed layer of the first-stage fluidized bed reactor is maintained; the fluidized bed reactor is arranged into a lifting pipe type fluidized bed reactor, a multi-section fluidized bed reactor which is vertically arranged, a multi-zone circulating reactor with an expanded end and a dense phase zone combined, and a combined fluidized bed reactor in the above form;
(8) Solid phase particles discharged from the first zone fluidized bed reactor and reducing gas enter the second zone fluidized bed reactor for continuous reaction, and a two-stage series cyclone separator is arranged at the top of the second zone fluidized bed reactor for separating gas phase products from solid phase product particles; the gas phase product separated by the cyclone separator arranged in the second-zone fluidized bed reactor and the produced gas of the first-zone fluidized bed enter a secondary heater to heat raw material sodium sulfate; the solid-phase product of the second-zone fluidized bed reactor is discharged from an interface at the material leg of the reactor, one part of the solid-phase product is returned to the first-zone fluidized bed reactor, and the other part of the solid-phase product is sent to a sodium sulfide-produced gas heat exchanger;
(9) Solid sodium sulfide products extracted from the sodium sulfide-produced gas heat exchanger firstly enter a steam superheater and then enter a waste heat boiler;
(10) Sodium sulfide products extracted by the waste heat boiler enter a sodium sulfide cooling and product packaging unit, sodium sulfide is continuously cooled by deoxidized water, nitrogen or circulating water, combustible reducing gas in a sodium sulfide gap is replaced by nitrogen, and finally the sodium sulfide enters a fluidized bed packaging system; an electromagnetic iron removing device is arranged before packaging to remove iron in the catalyst, and the iron enters a catalyst tank to continue the cyclic reaction.
6. The sodium sulfide production process according to claim 5, wherein: the sodium sulfate solid-phase particles in the step (1) are sodium sulfate solid-phase particles with industrial-grade purity; the catalyst comprises one or more of iron and iron oxide; the reducing gas in the step (5) comprises one or more of hydrogen, methane and carbon monoxide; the molar ratio of the reducing gas to sodium sulfate entering the first zone fluidized bed reactor in the step (7) is larger than the ratio of stoichiometric coefficient, excessive reducing gas is used for entering the reactor, the hydrogen excess coefficient is preferably larger than 1.1, and the excess coefficients of the three reducing gases are carbon monoxide > methane > hydrogen; the mass ratio of the catalyst to the sodium sulfate is more than 0.1 percent.
7. The sodium sulfide production process according to claim 5, wherein: and (3) conveying the solid-phase material in the step (6) through pipelines, wherein loose gas is arranged in the pipelines, and the loose gas is reducing gas or steam with higher pressure than the system or nitrogen with higher pressure than the system.
8. The sodium sulfide production process according to claim 7, wherein: the reaction pressure of the first-zone fluidized bed reactor is controlled to be 0.05-7.0MPa; the reaction temperature is controlled between 620 ℃ and 1000 ℃; the reaction pressure of the fluidized bed reactor in the second zone is controlled to be 0.05-7.0MPa; the temperature of the fluidized bed reactor is controlled below 1100 ℃; a heating or heat-taking tube bundle is arranged in the fluidized bed reactor; the fluidized bed reactor is provided with an excessive effective reducing gas molar excess coefficient larger than 1.1; in the fluidized bed reactor, the reaction time of sodium sulfate is adjusted according to the effective components of the reducing gas, the pressure of the reactor and the form of the reactor, and the reaction time is 0.5-2 hours.
9. The sodium sulfide production process according to claim 5 or 6, wherein: the pressure of the externally supplied reducing gas is higher, the reducing gas pressure energy is utilized to expand the turbine, the reducing gas compressor-blower or the produced gas induced draft fan of the system is driven to do work, and meanwhile, the reducing gas turbine is utilized to expand to provide flow velocity kinetic energy for the reducing gas; the fluidized bed reactor pressure is reduced by reducing the reducing gas pressure and the system overall pressure.
10. The sodium sulfide production process according to claim 5 or 6, wherein: and (3) cooling sodium sulfide in the step (10) by adopting a chilling flow, mixing sodium sulfide solid and deionized water to prepare a solution product, and standing and precipitating to separate out a catalyst in the solution.
CN202210256561.2A 2022-01-06 2022-03-16 Sodium sulfide production system and process for gas-phase fluidization reduction of sodium sulfate Active CN114408869B (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202210007591 2022-01-06
CN202210007591X 2022-01-06

Publications (2)

Publication Number Publication Date
CN114408869A CN114408869A (en) 2022-04-29
CN114408869B true CN114408869B (en) 2023-07-14

Family

ID=81264124

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210256561.2A Active CN114408869B (en) 2022-01-06 2022-03-16 Sodium sulfide production system and process for gas-phase fluidization reduction of sodium sulfate

Country Status (1)

Country Link
CN (1) CN114408869B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115193252A (en) * 2022-07-29 2022-10-18 郑州家善环保科技有限公司 Regeneration and cyclic utilization method of desulfurization solid waste sodium sulfate
CN115744935A (en) * 2022-09-30 2023-03-07 常州江南冶金科技有限公司 Process for improving purity of sodium sulfate
CN115784168B (en) * 2022-12-14 2024-03-15 攀钢集团攀枝花钢铁研究院有限公司 Process and method for continuously preparing sodium sulfide by directly reducing sodium sulfate by fuel gas

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9117936D0 (en) * 1991-08-20 1991-10-09 Canada Inc Production of sodium hydroxide
CN100400413C (en) * 2006-05-16 2008-07-09 内蒙古工业大学 Method for preparing low-iror anhydrous sodium sulfide by one-step reduction of Glauber salt from coke oven gas
CN101585512A (en) * 2009-06-18 2009-11-25 赵志军 Method of producing anhydrous sodium sulfide without pollution
CN106395758A (en) * 2016-07-01 2017-02-15 马艳玲 A method of producing high-purity sodium sulfide
CN106185836A (en) * 2016-07-01 2016-12-07 马艳玲 High-pure anhydrous sodium sulfide production method
CN113772632A (en) * 2021-09-29 2021-12-10 西南科技大学 Method for producing sodium sulfide by suspending sodium sulfate

Also Published As

Publication number Publication date
CN114408869A (en) 2022-04-29

Similar Documents

Publication Publication Date Title
CN114408869B (en) Sodium sulfide production system and process for gas-phase fluidization reduction of sodium sulfate
US4017272A (en) Process for gasifying solid carbonaceous fuel
US9994453B2 (en) Process and system for producing commercial quality carbon dioxide from recausticizing process calcium carbonates
US8480768B2 (en) Hot solids gasifier with CO2 removal and hydrogen production
US8865101B2 (en) Process and system for producing commercial quality carbon dioxide from high solids lime mud
JP5378361B2 (en) Improved method for synthesizing urea
EA034603B1 (en) Process for the production of formaldehyde
EA033955B1 (en) Integrated process for the production of formaldehyde-stabilized urea
CN103666611B (en) System and method for preparing alternative natural gas
US10214448B2 (en) High temperature hydrator
US3310381A (en) Process for producing high purity oxygen by chemical means
CN100404137C (en) Industrial reduction method of particle iron-base fischer-tropsch synthesis catalyst
CN101830434A (en) Method for producing synthetic gas by natural gas conversion
CN108517227B (en) Industrial gas preparation system and industrial gas preparation method
US4756893A (en) Utilization of sulphur dioxide for energy production
CN215364900U (en) Process system for chemical ring hydrogen production
US3460912A (en) Producing sulfur from calcium sulfate
CN103484180A (en) Technology for preparing natural gas through self-heating catalytic gasification of fire coal, and system thereof
CN114057277A (en) Waste alkali wet oxidation system and method
CN112225639A (en) Methanol purge gas recycling system and process
CN105347302B (en) A kind of method of natural gas conversion production synthesis gas
CN221526569U (en) Energy-saving device for recovering waste heat of coal chemical industry transformation
CN210030052U (en) Energy-saving sulfuric acid production line
CN111003692B (en) Sulfur dioxide recycling system and method
CN112142003B (en) Carbon monoxide conversion process

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant