CN104030247B - HCl oxidation reaction process and system with fluidized bed and adiabatic fixed bed connected in series - Google Patents

Abstract

The invention discloses a HCl oxidation reaction process and system in which a fluidized bed and an adiabatic fixed bed are connected in series. The reaction process comprises the following steps: uniformly mixing hydrogen chloride and oxygen, entering a fluidized bed reactor for oxidation reaction, and reacting mixed gas leaving The fluidized bed reactor, after heat exchange, reduces the temperature of the reaction mixture gas to a temperature of 350-410°C, and then enters the adiabatic fixed bed reactor connected in series with the fluidized bed for further oxidation reaction. Among them, the conversion rate of hydrogen chloride in the fluidized bed reactor is 30% to 70%, and the reaction mixed gas after the reaction in the fluidized bed reactor enters the fixed bed reactor for adiabatic reaction, and the highest conversion rate of hydrogen chloride can reach Up to 92.1%.

Description

A HCl oxidation reaction process and system in which a fluidized bed and an adiabatic fixed bed are connected in series

technical field

The invention relates to a reaction process and system for producing chlorine by catalytic oxidation of hydrogen chloride, in particular to a reaction process for producing chlorine by oxidizing hydrogen chloride in a system in which a fluidized bed reactor and an adiabatic fixed bed reactor are connected in series.

Background technique

In the production of bulk chlorine-related products such as polyurethane intermediates (MDI, TDI, etc.), fluorine material intermediates, benzaldehyde, and potassium chloride, the by-product hydrogen chloride is difficult to handle and even pollutes the environment, which has become a bottleneck restricting the further development of related enterprises . By catalytic oxidation, the by-product hydrogen chloride is oxidized into chlorine gas to realize the recycling of chlorine resources, which is expected to become a technical approach for resource utilization of by-product hydrogen chloride in chlorine-related industries.

There are two main methods for converting by-product hydrogen chloride into chlorine gas. One is to use electrolysis of hydrochloric acid, such as the method for preparing chlorine and hydrogen by electrolysis of dilute waste hydrochloric acid described in patent CN201010528518.4; patent CN98812166.2 uses oxygen-consuming cathode electrolysis Hydrochloric acid, get chlorine and hydrogen, the purity of chlorine can reach more than 99%. The preparation of chlorine gas by electrolysis of hydrochloric acid is at the cost of consuming a large amount of electric energy. The power consumption per ton of chlorine gas exceeds 1700kWh, and the production cost of chlorine is relatively high.

Another method for converting hydrogen chloride into chlorine is the gas-solid catalytic oxidation method, and the reaction formula is shown below.

$\mathrm{<span\; class="notranslate">\; HCl</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 4</span>}{\mathrm{<span\; class="notranslate">\; o</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&DoubleLeftRightArrow;</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; Cl</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; o</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 298</span>}\mathrm{<span\; class="notranslate">\; K</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 28.4</span>}\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; mol</span>}$

In the gas-solid catalytic oxidation method, there are mainly two types of reactors for oxidizing hydrogen chloride to chlorine: fixed bed and fluidized bed. The method for carrying out the oxidation reaction in a fixed bed reactor, as reported in patent CN201010567038.9, uses copper chloride as the main active component, uses molecular sieves as the carrier, adds boron, alkali metals, rare earth metals and alkaline earth metals, and uses two The hydrogen chloride oxidation catalyst is prepared by a one-step impregnation method. When the reaction pressure is 0.1-0.6MPa, the reaction temperature is 320-460°C, and the mass space velocity of hydrogen chloride is 0.1-2.5h ^-1 , the conversion rate of hydrogen chloride can reach more than 85%. Patent 200810196433.3 discloses a hydrogen chloride oxidation catalyst prepared by using ^REY molecular sieve as the carrier and copper chloride, rare earth nitrate and alkali metal salt as the active precursor. Under the condition of feed rate of h/kg, the conversion rate of hydrogen chloride is about 85%. In addition to the hydrogen chloride oxidation method carried out in a single fixed-bed reactor, the patent CN200710023245.6 adopts a series reaction-dehydration coupling method of multiple fixed-bed reactors, and dehydrates the water generated by the reaction from the reaction system through inter-stage condensation. In addition, it breaks the limitation of chemical reaction balance and improves the conversion rate of hydrogen chloride. However, in order to condense and dehydrate, the temperature of the reaction gas needs to drop from 430°C to below 100°C, and then rise to about 400°C before entering the next reactor. This process consumes a lot of energy and is economically unfavorable. And the hydrochloric acid produced by condensation seriously corrodes the condensation equipment between the stages.

The hydrogen chloride oxidation reaction process carried out in the fluidized bed is reported as document [Mortensen, etal. After chemical adsorption and then oxidation reaction to release chlorine, the conversion rate of hydrogen chloride can reach almost 100%. However, since the catalyst is transported back and forth in two series fluidized beds, the wear and tear on the catalyst and reaction equipment is extremely serious, and the requirements on the physical properties of the catalyst and the material of the equipment are extremely strict, which is not conducive to industrial production.

In addition to the above two main reaction processes, CN200880024532.1 discloses a method for producing chlorine by oxidation of hydrogen chloride in at least 18 adiabatic fixed-bed reactors connected in series. The outlet temperature of each adiabatic bed catalyst is 370°C, and the final HCl The conversion rate can reach 88%. However, this method has too many series reactors, high equipment manufacturing cost, complicated process lines, cumbersome operation, and difficulties in practical application. And CN200980139740.0 then discloses the method that 3 adiabatic fixed beds are connected in series to carry out the oxidation oxidation of hydrogen chloride to produce chlorine, wherein in each adiabatic fixed bed, respectively fill ruthenium-based and uranium-based two kinds of catalysts with different activities, after the series adiabatic reaction, hydrogen chloride The conversion rate can reach about 90%. Although the number of reactors in series is small, the outlet temperature reaches 470°C, and the temperature rise of a single reactor reaches over 150°C, which imposes strict requirements on the stability of the catalyst, and it is easy to burn out the catalyst due to overheating.

The reaction of hydrogen chloride oxidation to chlorine is an exothermic reaction. When a fixed bed reactor is used, there are obvious hot spots in the catalyst bed. If the operation is not proper, it is very likely that the catalyst will burn out due to overheating. In order to remove the heat of reaction in time, a tubular reactor is usually used, but due to the strong corrosiveness of the reaction system, the cost of the tubular reactor is high. The adiabatic fixed-bed reactor is simple to prepare, low in cost, and convenient to operate and control. However, the exothermic heat (28.4kJ/molHCl) during the hydrogen chloride oxidation reaction is relatively large, and the adiabatic temperature rise will reach 453.1°C when the molar ratio of hydrogen chloride to oxygen is 1/1, and a single adiabatic fixed-bed reactor can be used to achieve higher conversion rate is impossible.

As we all know, the fluidized bed reactor has good heat transfer performance, simple equipment structure and low cost, but due to the obvious back-mixing phenomenon, the conversion rate of the reactants is relatively low compared with the fixed bed.

Contents of the invention

The inventor has proved through a large number of experiments that the combination of fluidized bed and adiabatic fixed bed reactor in series can remove the Most of the heat of reaction then enters the subsequent series of adiabatic fixed-bed reactors for reaction, which can increase the conversion rate as much as possible. By combining multiple adiabatic fixed beds in series, the reaction temperature in each adiabatic fixed bed reactor is within the range that the catalyst can bear. Combining a fluidized bed reactor with multiple adiabatic fixed bed reactors in series can not only greatly reduce the equipment cost and production cost, but also the conversion rate of hydrogen chloride can meet the requirements of industrial operation.

Therefore, the object of the present invention is to provide a method for preparing chlorine by catalytic oxidation of hydrogen chloride, specifically a method for converting hydrogen chloride into chlorine in a series fluidized bed reactor and an adiabatic fixed bed reactor.

Another object of the present invention is to provide a reaction system in which the fluidized bed reactor is connected in series with the adiabatic fixed bed reactor.

The purpose of the present invention is achieved in the following manner:

A method for producing chlorine by catalytic oxidation of hydrogen chloride, the method comprising the following steps: uniformly mix hydrogen chloride and oxygen, enter a fluidized bed reactor for oxidation reaction, react the mixed gas out of the fluidized bed reactor, undergo heat exchange, and mix the reaction The gas temperature is lowered to 350-410°C, and then enters the adiabatic fixed-bed reactor connected in series with the fluidized bed for further oxidation reaction. Oxygen in the present invention is a general term for "oxygen", which can be gaseous oxygen or liquid oxygen.

In the above method, the hydrogen chloride oxidation reaction is carried out in a series fluidized bed reactor and an adiabatic fixed bed reactor. The hydrogen chloride and oxygen are mixed evenly, and firstly reacted in the fluidized bed reactor, and the reaction mixture enters the series series after heat exchange. Continue to react in an adiabatic fixed-bed reactor to generate chlorine gas.

In the above method, the number of fluidized bed reactors is 1, and the number of adiabatic fixed bed reactors is 1 to 6, preferably 2 to 5. The loading amount of the catalyst in the adiabatic fixed-bed reactor shall be loaded according to the method of W _N-1 /W _N =1.3～2.7 (2<N<6), and W _N is the catalyst loading in the Nth adiabatic fixed-bed reactor connected in series Amount, W _N-1 is the loading amount of catalyst in the N-1th adiabatic fixed-bed reactor. When there are multiple adiabatic fixed-bed reactors, the multiple adiabatic fixed-bed reactors are combined and connected in series; heat exchangers or heat exchange spaces or heat exchangers and heat exchange spaces are arranged between multiple adiabatic fixed-bed reactors. The spaces are set alternately.

In the above method, the conversion rate of hydrogen chloride in the fluidized bed reactor is 30%-70%, preferably 40%-60%.

In the above method, after the reaction mixed gas reacted in the fluidized bed reactor leaves the fluidized bed reactor, the temperature of the reaction mixed gas is reduced to 350-410° C. through indirect heat exchange. The indirect heat exchange means that the reaction mixture passes through the metal wall and transfers heat to the cooling medium on the other side of the metal wall. The heat obtained by the above cooling medium in the indirect heat exchange process is used for preheating hydrogen chloride and oxygen , can also be used to generate high-pressure steam. The cooling medium in the present invention can be molten salt. The heat obtained by the molten salt can be used for preheating hydrogen chloride and oxygen, and can also be used to generate high-pressure steam.

In the above method, after the reaction mixed gas reacted in the fluidized bed reactor leaves the fluidized bed reactor, the temperature of the reaction mixed gas can also be reduced to 350-410° C., preferably 360° C., by means of direct heat exchange. ~380°C. The direct heat exchange method refers to the direct contact between the reaction mixture gas and the cooling medium to reduce the temperature of the reaction mixture gas. The cooling medium mentioned here refers to a mixed gas of hydrogen chloride and oxygen, gaseous oxygen or liquid oxygen, preferably gaseous oxygen or liquid oxygen is used as the cooling medium, more preferably liquid oxygen is used as the cooling medium. The direct heat exchange in the present invention refers to the direct contact of the reaction mixture gas with the mixture gas of low-temperature hydrogen chloride and oxygen, gaseous oxygen or liquid oxygen for cooling, and the temperature of the cooled reaction mixture gas is reduced to 350-410°C.

When there are two or more adiabatic fixed-bed reactors connected in series with the fluidized bed reactor, multiple adiabatic fixed-bed reactors are combined and connected in series, and the reaction between the series-connected adiabatic fixed-bed reactors The temperature of the mixed gas is reduced to 350-410°C after indirect or direct heat exchange.

In the above method, specifically, the reaction mixed gas coming out of the fluidized bed reactor enters the series adiabatic fixed bed reactors to continue the reaction after heat exchange. When there are two adiabatic fixed-bed reactors connected in series with the fluidized bed reactor, the reaction mixture gas between the first adiabatic fixed-bed reactor can reduce the temperature of the reaction mixture gas to 350-410 through indirect heat exchange. °C, preferably 360-380 °C, and then enter the second adiabatic fixed-bed reactor in series; when N (2<N<6) adiabatic fixed-bed reactors are connected in series, the After the reaction mixed gas comes out, through indirect heat exchange, the temperature of the reaction mixed gas is lowered to 350-410°C, preferably 360-380°C, and then enters the Nth adiabatic fixed-bed reactor connected in series to continue the reaction. The reaction mixed gas coming out of the Nth adiabatic fixed bed reactor, through indirect heat exchange, reduces the temperature of the reaction mixed gas to 120-200°C, preferably 150-180°C, and enters the subsequent section.

In the above method, the reaction mixed gas coming out of the fluidized bed reactor can also enter the series adiabatic fixed bed reactor after heat exchange to continue the reaction. When there are two adiabatic fixed-bed reactors connected in series with the fluidized bed reactor, the reaction mixed gas between the first adiabatic fixed-bed reactor is passed through mixed gas with low-temperature hydrogen chloride and oxygen, gaseous oxygen or liquid oxygen Wait for direct contact with the cooling medium, reduce the temperature of the reaction mixture gas to 350-410°C, and then enter the second adiabatic fixed-bed reactor in series; when connecting N sets (2<N<6) of adiabatic fixed-bed reactors in series, start The reaction mixture gas from N-1 adiabatic fixed-bed reactors is directly contacted with cooling medium such as low-temperature hydrogen chloride and oxygen mixture gas, gaseous oxygen or liquid oxygen, and the temperature of the reaction mixture gas is reduced to 350-410°C before entering the series The Nth adiabatic fixed-bed reactor of the Nth unit continues the reaction. The reaction mixture gas coming out of the N adiabatic fixed-bed reactor, through indirect heat exchange, reduces the temperature of the reaction mixture gas to 150-200°C, and then enters the subsequent section.

In the above method, when entering the fluidized bed reactor, the mol ratio of oxygen to hydrogen chloride is 1/8～2/1, preferably 1/4～1/1; the reaction pressure in the fluidized bed reactor is 1～10 atm (absolute pressure), preferably 3 to 8 atm (absolute pressure); the reaction temperature is 380 to 430°C.

In the above method, the reaction temperature of the reaction mixture gas in the adiabatic fixed-bed reactor is 350-450° C., preferably 380-430° C., and the reaction pressure is 1-10 atm, preferably 3-8 atm.

The catalyst used in the adiabatic fixed-bed reactor in the present invention can be a noble metal catalyst, such as commercialized ruthenium catalyst, gold catalyst, etc.; it can also be a transition metal catalyst, such as copper catalyst, chromium catalyst, etc. The shape of the catalyst may have any desired shape, such as spherical, cylindrical, ring, star, clover-shaped particles or flakes.

The feed rate of the hydrogen chloride through the fluidized bed is 0.75-7.5 Nm ³ /kg catalyst/h.

A system for the above-mentioned method for producing chlorine by catalytic oxidation of hydrogen chloride, the system comprises a fluidized bed reactor and one or more adiabatic fixed bed reactors, and the fluidized bed reactor and the adiabatic fixed bed reactor are connected in series way to combine joins. When there are multiple adiabatic fixed-bed reactors, the multiple adiabatic fixed-bed reactors are combined and connected in series; heat exchangers or heat exchange spaces or heat exchangers and heat exchange spaces are arranged between multiple adiabatic fixed-bed reactors. The spaces are set alternately.

Compared with the prior art, the advantages of the present invention are: compared with conventional fluidized bed reactors and tubular fixed bed reactors, the method of series reaction of fluidized bed reactors and adiabatic fixed bed reactors of the present invention has the advantages of It lies in: ① After the series reaction of the fluidized bed reactor and the adiabatic fixed bed reactor, the good heat transfer performance of the fluidized bed is used to remove part of the heat of reaction from the reaction system, and by controlling the reaction amount of hydrogen chloride in the fluidized bed reactor , the heat that can be removed in the fluidized bed reactor can be controlled, and the heat generated by the reaction in the series adiabatic fixed bed reactor can be controlled at the same time. Therefore, the phenomenon of runaway temperature caused by strong reaction heat release in the tubular fixed bed reactor can be avoided. ② Compared with the tube-and-tube heat exchange fixed-bed reactor alone, the structure of the fluidized-bed reactor and the adiabatic fixed-bed reactor are significantly simplified, the cost is low, and the preparation of the reactor and the scale-up performance of the process are simplified.

Description of drawings

Fig. 1 is the system for producing chlorine by catalytic oxidation of hydrogen chloride in series with fluidized bed reactor and 4 adiabatic reactors of the present invention.

The labels in the figure are: 1-hydrogen chloride feed pipeline; 2-oxygen feed pipeline; 3-fluidized bed reactor; 4-reaction mixed gas feed-liquid pipeline; 5-reaction mixed gas feed-liquid pipeline after heat exchange; 6 - The discharge pipeline of the reaction mixture gas after the reaction in 4 adiabatic fixed-bed reactors. AR1 - the first adiabatic fixed bed reactor, AR2 - the second adiabatic fixed bed reactor, AR3 - the third adiabatic fixed bed reactor, AR4 - the fourth adiabatic fixed bed reactor. E1 - the first heat exchanger, E2 - the first heat exchange space, E3 - the second heat exchange space, E4 - the third heat exchange space, E5 - the second heat exchanger.

In the figure, the fluidized bed reactor is connected in series with 4 adiabatic fixed bed reactors connected in series, and there is a direct heat exchange space between the 4 adiabatic fixed bed reactors connected in series, which can be used for low-temperature medium to enter the back and front The high-temperature reaction gas mixture at the outlet of an adiabatic fixed-bed reactor performs heat exchange.

Before entering the fluidized bed reactor, hydrogen chloride enters the fluidized bed reactor 3 after being mixed with oxygen. After the reaction mixture gas after the fluidized bed reaction passes through the heat exchanger E1 for heat exchange, the heat exchange reaction mixture gas is obtained. The heat exchange method in E1 adopts indirect heat exchange, that is, the reaction generated by the fluidization reaction is converted into molten salt by molten salt. The heat was removed from the reaction system. The reaction mixture gas after heat exchange enters the first adiabatic bed reactor AR1, and the high temperature reaction mixture gas after adiabatic reaction exchanges heat directly with the cooling medium in E2, that is, the gas entering the heat exchange space of E2, except for high temperature In addition to the reaction gas, there is also a mixed gas of low-temperature hydrogen chloride and oxygen with the same composition as that entering AR1. The cooling medium enters the heat exchanger at the outlet of each adiabatic reactor. Similarly, the reaction mixed gas obtained by mixing in E2 enters the second adiabatic reactor AR2, and the reaction mixed gas after the adiabatic reaction enters the mixed gas of low-temperature hydrogen chloride and oxygen with the same composition in AR1 in the heat exchange space of E3. After heat exchange, it enters the third adiabatic reactor AR3. After the adiabatic reaction in AR3, the reaction mixed gas is obtained. In the heat exchange space of E4, the mixed gas of low-temperature hydrogen chloride and oxygen with the same composition as that entering AR1 is exchanged for heat, and then enters the fourth adiabatic reactor AR4, and is fixed by four adiabatic reactors. After the reaction in the bed reactor, the reaction mixed gas enters the subsequent process flow after the reaction heat is discharged from the system through indirect heat exchange in E5.

Fig. 2 is a system for producing chlorine by catalytic oxidation of hydrogen chloride in series with a fluidized bed reactor and three adiabatic reactors of the present invention.

The labels in the figure are: 1-hydrogen chloride feed pipeline; 2-oxygen feed pipeline; 3-fluidized bed reactor; 4-reaction mixed gas feed-liquid pipeline; 5-reaction mixed gas feed-liquid pipeline after heat exchange; 6 - The reaction mixture gas pipeline after passing through the first adiabatic fixed bed reactor; 7 - The reaction mixture gas pipeline after passing through the first adiabatic fixed bed reactor and exchanging heat; 8 - The reaction mixture gas pipeline passing through the second adiabatic fixed bed reactor The reaction mixed gas pipeline after reaction; 9 - the reaction mixed gas pipeline after passing through the second adiabatic fixed bed reactor and heat exchange; 10 - the reaction mixed gas pipeline after passing through the third adiabatic fixed bed reactor; 11 - The reaction mixture gas pipeline after passing through the third adiabatic fixed-bed reactor and exchanging heat. AR1 - the first adiabatic fixed bed reactor, AR2 - the second adiabatic fixed bed reactor, AR3 - the third adiabatic fixed bed reactor, the first heat exchanger of E1, the second heat exchanger of E2, E3 Third heat exchanger, E4 fourth heat exchanger.

In the figure, the fluidized bed reactor is connected in series with the combination of 3 series-connected adiabatic fixed-bed reactors, and a molten salt heat exchange system is set between the 3 series-connected adiabatic fixed-bed reactors for indirect heat exchange and removal reaction hot. Before entering the fluidized bed reactor, hydrogen chloride enters the fluidized bed reactor 3 after being mixed with oxygen. After the fluidized bed reaction, the reaction mixed gas passes through the first heat exchanger E1 for indirect heat exchange, and then enters the first adiabatic reactor AR1, and the reacted mixed gas undergoes indirect heat exchange in the second heat exchanger E2 After that, it enters the second adiabatic bed reactor AR2, and the generated reaction mixed gas undergoes indirect heat exchange in the third heat exchanger E3, and then enters the third adiabatic bed reactor, and the generated reaction mixed gas passes through the fourth heat exchanger After the indirect heat exchange in the heat exchanger E4, the heat of reaction is discharged from the system. The reaction mixed gas obtained by the reaction enters the subsequent process flow.

detailed description

The present invention is further explained by the following examples:

As shown in Figures 1 to 2, a system for producing chlorine by catalytic oxidation of hydrogen chloride comprises a fluidized bed reactor 3 and one or more adiabatic fixed bed reactors AR1 to 6, and the fluidized bed reactor and The adiabatic fixed bed reactors are combined and connected in series. When there are multiple adiabatic fixed-bed reactors, the multiple adiabatic fixed-bed reactors are combined and connected in series; heat exchangers or heat exchange spaces or heat exchangers and heat exchange spaces are arranged between multiple adiabatic fixed-bed reactors. The spaces are set alternately.

Example 1:

In Example 1, after hydrogen chloride is mixed with oxygen, it first passes through the fluidized bed reactor, and after the reaction in the fluidized bed reactor, the resulting reaction mixture is heat exchanged through a heat exchanger, and then passes through a total of 4 adiabatic fixed bed reactors .

Hydrogen chloride and oxygen enter the fluidized bed reactor at a molar ratio of 2, the inlet pressure of the fluidized bed reactor is 10 atm, and the fluidized reaction temperature is 400°C. Hydrogen chloride passes through the fluidized bed at a feed rate of 6Nm ³ /kg catalyst/h. The CeCuK/Y molecular sieve catalyst loading in the fluidized bed is 1532kg. After the reaction, the conversion rate of hydrogen chloride at the outlet of the fluidized bed reactor is 30%. After indirect heat exchange, the temperature of the reaction mixture gas entering the first adiabatic fixed-bed reactor is 350°C. There are 4 adiabatic fixed-bed reactors in series, and the inlet temperature of the catalyst layer in each adiabatic fixed-bed reactor is 350°C, the outlet temperature is 430°C, and the catalyst loadings in 1 to 4 adiabatic fixed-bed reactors are 1185.7kg, 1797.3kg, 3118.1kg and 7280.4kg in sequence. Indirect heat exchange is adopted between adiabatic fixed-bed reactors, that is, the reaction mixture gas contacts the low-temperature heat exchange medium through the metal wall surface. After the fluidized bed reacts in series with four adiabatic fixed-bed reactors, the total mass space velocity of hydrogen chloride reaches 1.0 h ^-1 , and the conversion rate of adiabatic hydrogen chloride reaches 85.7%. The inlet and outlet temperatures, catalyst loading and reaction results of each adiabatic fixed-bed reactor are shown in Table 1.

Table 1

Adiabatic bed reactor Unit 1 2nd unit Unit 3 Unit 4 Inlet temperature/℃ 350 350 350 350 Outlet temperature/℃ 430 430 430 430 Catalyst mass/kg 1185.7 1797.3 3118.1 7280.4 Total conversion at the outlet of each reactor/% 44.6 58.1 73.6 85.7

Example 2:

In Example 2, after hydrogen chloride and oxygen are mixed, they first pass through the fluidized bed reactor, and after the reaction in the fluidized bed reactor, the resulting reaction mixture passes through a heat exchanger for heat exchange, and then passes through a total of 4 adiabatic catalytic reactors.

Hydrogen chloride and oxygen enter the fluidized bed reactor at a molar ratio of 1, the inlet pressure of the fluidized bed reactor is 6atm, and the fluidized reaction temperature is 380°C. Hydrogen chloride passed through the fluidized bed at a feed rate of 6Nm ³ /kg catalyst/h, the catalyst loading in the fluidized bed was 1532kg, and the conversion rate of hydrogen chloride at the outlet of the fluidized bed reactor after the reaction was 36%. After indirect heat exchange, the temperature of the reaction mixture gas entering the first adiabatic bed reactor is 350°C. There are 4 adiabatic reactors connected in series. The inlet temperature of the catalyst layer in each adiabatic reactor is 350°C, and the outlet temperature is Both are at 430°C, and the catalyst loadings in 1 to 4 adiabatic reactors are 994.0kg, 1781.0kg, 4656.0kg and 7722.5kg in sequence. Indirect heat exchange is adopted between the adiabatic reactors, that is, the reaction mixture gas is not in contact with the low-temperature heat exchange medium. After the fluidized bed reacts in series with four adiabatic fixed-bed reactors, the total mass space velocity of hydrogen chloride reaches 0.9h ^-1 , and the conversion rate of adiabatic hydrogen chloride reaches 88.3%. The inlet and outlet temperatures, catalyst loading and reaction results of each adiabatic reactor are shown in Table 2.

Table 2

Adiabatic bed reactor Unit 1 2nd unit Unit 3 Unit 4 Inlet temperature/℃ 350 350 350 350 Outlet temperature/℃ 430 430 430 374 Catalyst mass/kg 994.0 1781.0 4656.0 7722.5 Total conversion at the outlet of each reactor/% 47.03 60.01 76.93 88.3

Example 3:

In embodiment 3, according to the schematic flow sheet shown in accompanying drawing 1, after hydrogen chloride and oxygen are mixed, at first pass through the fluidized bed reactor, after the fluidized bed reactor reacts, the reaction mixed gas that obtains is heat-exchanged through the heat exchanger, It then passes through a total of 3 adiabatic reactors.

Hydrogen chloride and oxygen enter the fluidized bed reactor at a molar ratio of 1, the inlet pressure of the fluidized bed reactor is 3atm, and the fluidized reaction temperature is 400°C. Hydrogen chloride passed through the fluidized bed at a feed rate of 2Nm ³ /kg catalyst/h, the catalyst loading in the fluidized bed was 3830.4kg, and the conversion rate of hydrogen chloride at the outlet of the fluidized bed reactor after the reaction was 60%. After indirect heat exchange, the temperature of the reaction mixture gas entering the first adiabatic bed reactor is 380°C. There are 3 adiabatic reactors in series, and the inlet temperature of the catalyst layer in each adiabatic reactor is 380°C and 390°C respectively. and 400°C, the outlet temperatures are 430°C, 430°C and 423.2°C respectively, and the catalyst loadings in 1 to 3 adiabatic reactors are 1401.4kg, 2210.2kg and 3955.7kg in sequence. After the series reaction between the fluidized bed and three adiabatic fixed beds, the total mass space velocity of hydrogen chloride is 1.1h ^-1 , and the conversion rate of hydrogen chloride reaches 85.4%. The inlet and outlet temperatures, catalyst loading and reaction results of each adiabatic reactor are shown in Table 3.

table 3

Adiabatic bed reactor Unit 1 2nd unit Unit 3 Inlet temperature/℃ 380 390 400 Outlet temperature/℃ 430 430 423.2 Catalyst mass/kg 1401.4 2210.2 3955.7 Total conversion at the outlet of each reactor/% 70.61 79.09 85.4

Example 4:

In Example 4, after hydrogen chloride is mixed with oxygen, it first passes through the fluidized bed reactor, and after the reaction in the fluidized bed reactor, the resulting reaction mixture is heat exchanged through a heat exchanger, and then passes through a total of 5 adiabatic fixed bed reactors .

Hydrogen chloride and oxygen enter the fluidized bed reactor at a molar ratio of 1, the inlet pressure of the fluidized bed reactor is 2 atm, and the fluidized reaction temperature is 430°C. Hydrogen chloride passed through the fluidized bed at a feed rate of 7.5Nm ³ /kg catalyst/h, and the catalyst loading in the fluidized bed was 1225.7kg. After the reaction, the conversion rate of hydrogen chloride at the outlet of the fluidized bed reactor was 30%. After passing through the heat exchanger, the temperature of the reaction mixture gas entering the first adiabatic bed reactor is 380°C. There are 5 adiabatic reactors connected in series, and the inlet temperature of the catalyst layer in each adiabatic bed reactor is 380°C. The temperature was all 430°C. The loading amount of catalysts in stages 1 to 5 is 376.3kg, 519.8kg, 781.2kg, 1357.8kg and 3340.6kg in sequence, and the total mass space velocity of hydrogen chloride is 3.5h ^{- 1.} The conversion rate of hydrogen chloride reaches 85.15%. The inlet and outlet temperatures of each adiabatic fixed-bed reactor and the loading amount of catalyst in each reaction are shown in Table 4.

Table 4

Adiabatic bed reactor Unit 1 2nd unit Unit 3 Unit 4 Unit 5 Inlet temperature/℃ 380 380 380 380 380 Outlet temperature/℃ 430 430 430 430 430 Catalyst mass/kg 376.3 519.8 781.2 1357.8 3340.6 Total conversion at the outlet of each reactor/% 41.67 52.32 62.95 73.56 85.15

Example 5:

Example 5 is a fluidized bed reactor connected in series with an adiabatic fixed bed reactor. Hydrogen chloride and oxygen enter the fluidized bed reactor at a molar ratio of 1, the inlet pressure of the fluidized bed reactor is 8atm, and the fluidized reaction temperature is 380°C. Hydrogen chloride passes through the fluidized bed at a feed rate of 1Nm ³ /kg catalyst/h, the catalyst loading in the fluidized bed is 8332kg, and the conversion rate of hydrogen chloride at the outlet of the fluidized bed reactor after the reaction is 70%. After passing through the heat exchanger, the temperature of the reaction mixture gas entering the adiabatic fixed-bed reactor is 350°C, the outlet temperature of the adiabatic fixed-bed reactor connected in series is 420°C, and the catalyst loading is 7129.7kg. The rate is 0.9h ^-1 , and the conversion rate of hydrogen chloride reaches 85.78%. The inlet and outlet temperatures and catalyst loadings of the adiabatic reactor are shown in Table 5.

table 5

Inlet temperature of adiabatic bed/℃ 350 Adiabatic bed outlet temperature/℃ 420 Catalyst mass/kg 7129.7 Total conversion at the outlet of each reactor/% 85.78

Embodiment 6:

Example 6 is a fluidized bed reactor connected in series with 5 adiabatic fixed bed reactors. Hydrogen chloride and oxygen enter the fluidized bed reactor at a molar ratio of 2, the inlet pressure of the fluidized bed reactor is 1 atm, and the fluidized reaction temperature is 410°C. Hydrogen chloride passed through the fluidized bed at a feed rate of 6Nm ³ /kg catalyst/h. The catalyst loading in the fluidized bed was 1838.6kg. After the reaction, the conversion rate of hydrogen chloride at the outlet of the fluidized bed reactor was 30%. After passing through the heat exchanger, the temperature of the reaction mixture gas entering the first adiabatic bed reactor is 400°C. There are 5 adiabatic reactors connected in series. The inlet temperature of the catalyst layer in each adiabatic reactor is 400°C, and the outlet temperature is Both are at 430°C, and the catalyst loadings in 1 to 5 adiabatic fixed-bed reactors are 246.2kg, 330.6kg, 481.1kg, 808.8kg and 2039.5kg in sequence. The total mass space velocity is 4.8h ^-1 , and the conversion rate of hydrogen chloride reaches 85.07%. The inlet and outlet temperatures, catalyst loading and reaction results of each adiabatic reactor are shown in Table 6.

Table 6

Adiabatic bed reactor Unit 1 2nd unit Unit 3 Unit 4 Unit 5 Inlet temperature/℃ 400 400 400 400 400 Outlet temperature/℃ 430 430 430 430 430 Catalyst mass/kg 246.2 330.6 481.1 808.8 2039.5

The total conversion rate at the outlet of each reactor/% 41.78 53.54 63.3 76.04 85.07

Embodiment 7:

Example 7 is a fluidized bed reactor connected in series with 5 adiabatic fixed bed reactors. Hydrogen chloride and oxygen enter the fluidized bed reactor with a molar ratio of 2, the inlet pressure of the fluidized bed reactor is 3atm, and the fluidized reaction temperature is 410°C. Hydrogen chloride passed through the fluidized bed at a feed rate of 6Nm ³ /kg catalyst/h. The catalyst loading in the fluidized bed was 1838.6kg. After the reaction, the conversion rate of hydrogen chloride at the outlet of the fluidized bed reactor was 38%. After passing through the heat exchanger, the temperature of the reaction mixture gas entering the first adiabatic bed reactor is 390°C. There are 5 adiabatic reactors in series, and the inlet temperature of the catalyst layer in each adiabatic reactor is 390°C. The catalyst loadings in 5 adiabatic fixed bed reactors are 886.1kg, 1589.3kg, 3691.3kg, 6705.9kg, and 8792.8kg in sequence. After the fluidized bed reacts with 5 adiabatic fixed beds in series, the total mass space velocity of hydrogen chloride is 1.2h ^-1 , the conversion rate of hydrogen chloride reaches 87.3%. The inlet and outlet temperatures, catalyst loading and reaction results of each adiabatic reactor are shown in Table 7.

Table 7

Adiabatic bed reactor Unit 1 2nd unit Unit 3 Unit 4 Unit 5 Inlet temperature/℃ 390 390 390 390 390 Outlet temperature/℃ 430 430 430 430 399.4 Catalyst mass/kg 886.1 1589.3 3691.3 6705.9 8792.8 The total conversion rate at the outlet of each reactor/% 45.03 58.03 71.01 83.98 87.3

Embodiment 8:

Example 8 is a fluidized bed reactor connected in series with 5 adiabatic fixed bed reactors. Hydrogen chloride and oxygen enter the fluidized bed reactor with a molar ratio of 2, the inlet pressure of the fluidized bed reactor is 8atm, and the fluidized reaction temperature is 430°C. Hydrogen chloride passed through the fluidized bed at a feed rate of 6Nm ³ /kg catalyst/h. The catalyst loading in the fluidized bed was 1838.6kg. After the reaction, the conversion rate of hydrogen chloride at the outlet of the fluidized bed reactor was 70%. After passing through the heat exchanger, the temperature of the reaction mixture gas entering the first adiabatic bed reactor is 390°C. There are 2 adiabatic reactors in series, and the inlet temperature of the catalyst layer in each adiabatic reactor is 390°C. The catalyst loadings in the two adiabatic fixed bed reactors are 1967.3kg and 4213.7kg respectively. After the series reaction between the fluidized bed and the two adiabatic fixed beds, the total mass space velocity of hydrogen chloride is 2.2h ^-1 , and the conversion rate of hydrogen chloride reaches 85.0 %. The inlet and outlet temperatures, catalyst loading and reaction results of each adiabatic reactor are shown in Table 8.

Table 8

Adiabatic bed reactor Unit 1 2nd unit Inlet temperature/℃ 390 390 Outlet temperature/℃ 430 430 Catalyst mass/kg 1967.3 4213.7 The total conversion rate at the outlet of each reactor/% 81.9 85.0

Embodiment 9:

In Example 9, hydrogen chloride mixed with oxygen was first passed through a fluidized bed reactor and then through a total of 4 adiabatic reactors connected in series.

Hydrogen chloride and oxygen enter the fluidized bed reactor with a molar ratio of 4, the inlet pressure of the fluidized bed reactor is 8atm, and the fluidized reaction temperature is 430°C. Hydrogen chloride passes through the fluidized bed at a feed rate of 0.75Nm ³ /kg catalyst/h. The catalyst loading in the fluidized bed is 12257.3kg. After the reaction, the conversion rate of hydrogen chloride at the outlet of the fluidized bed reactor is 45%. After passing through the heat exchanger, the temperature of the reaction mixture gas entering the first adiabatic fixed-bed reactor is 350°C. There are 4 adiabatic fixed-bed reactors in series, and the inlet temperature of the catalyst layer in each reaction is 350°C. 1 The outlet temperature of the catalyst bed in ~4 reactors is 430°C, the outlet temperature of the catalyst bed in the fourth reactor is 383.5°C, and the catalyst loading in 1~4 reactors is 3025kg, 5254kg, 12127kg and 18481kg, through the series reaction of fluidized bed reactor and 4 adiabatic fixed bed reactors, the total mass space velocity of hydrogen chloride is 0.3h ^-1 , and the conversion rate of hydrogen chloride reaches 85.94%. The inlet and outlet temperatures, catalyst loading and reaction results of each adiabatic fixed-bed reactor are shown in Table 9.

Table 9

Adiabatic bed reactor Unit 1 2nd unit Unit 3 Unit 4 Inlet temperature/℃ 350 350 350 350 Outlet temperature/℃ 430 430 430 383.5 Catalyst mass/kg 3025 5254 12127 18481 The total conversion rate at the outlet of each reactor/% 55.29 65.54 75.76 85.94

Example 10:

In Example 10, after hydrogen chloride and oxygen are mixed, they first pass through the fluidized bed reactor, and then pass through a total of 3 adiabatic fixed bed reactors, and the reaction is mixed by direct cooling between two adiabatic fixed bed reactors. The gas is reduced to the desired temperature.

Hydrogen chloride and oxygen enter the fluidized bed reactor with a molar ratio of 2, the inlet pressure of the fluidized bed reactor is 5 atm, and the fluidized reaction temperature is 420°C. Hydrogen chloride passed through the fluidized bed at a feed rate of 2Nm ³ /kg catalyst/h. The catalyst loading in the fluidized bed was 1838.6kg. After the reaction, the conversion rate of hydrogen chloride at the outlet of the fluidized bed reactor was 50%. The temperature of the reaction mixture gas at the outlet of the fluidized bed reactor is 420°C. The gas is cooled with 772Nm ³ /h of oxygen to reduce its temperature to 371.5°C, and enters the first adiabatic fixed bed reactor for reaction; At the outlet of the first adiabatic fixed bed reactor, the temperature of the reaction mixture gas is 430°C; the gas is quenched with 907.9Nm ³ /h of oxygen to reduce its temperature to 378.9°C, and then enters the second adiabatic fixed bed The reactor reacts; at the outlet of the second adiabatic fixed-bed reactor, the temperature of the reaction mixture gas is 430°C; the gas is cooled with 908.4Nm ³ /h of oxygen to reduce its temperature to 384.6°C, and then enters The reaction was carried out in the third adiabatic fixed-bed reactor; at the outlet of the third adiabatic fixed-bed reactor, the temperature of the reaction mixture gas was 396.3°C.

The catalyst loadings in the first to third adiabatic fixed bed reactors are 1962.3kg, 4059.2kg and 5674kg in sequence. After the series reaction between the fluidized bed and the three adiabatic fixed beds, the total mass space velocity of hydrogen chloride is 0.4h ^-1 , and the hydrogen chloride The ratio to the total moles of oxygen is 1/1.2, and the conversion rate of hydrogen chloride reaches 92.1%. The inlet and outlet temperatures, catalyst loading and reaction results of each adiabatic fixed-bed reactor are shown in Table 10.

Table 10

Adiabatic bed reactor Unit 1 2nd unit Unit 3 Inlet temperature/℃ 371.5 378.9 384.6 Outlet temperature/℃ 430 430 396.3 Catalyst mass/kg 1962.3 4059.2 5674 The total conversion rate at the outlet of each reactor/% 67.42 81.97 92.1

Example 11:

In Example 11, hydrogen chloride mixed with oxygen was passed first through a fluidized bed reactor and then through a total of 4 adiabatic reactors connected in series.

Hydrogen chloride and oxygen enter the fluidized bed reactor in a molar ratio of 6. The inlet pressure of the fluidized bed reactor is 6 atm, and the fluidized bed reaction temperature is 430°C. Hydrogen chloride passes through the fluidized bed at a feed rate of 1Nm ³ /kg catalyst/h, the catalyst loading in the fluidized bed is 10455.2kg, and the conversion rate of hydrogen chloride at the outlet of the fluidized bed reactor is 30%. After passing through the heat exchanger, the temperature of the reaction mixture gas entering the first adiabatic fixed-bed reactor is 350°C. There are 4 adiabatic fixed-bed reactors connected in series, the inlet temperature of the catalyst layer in each reactor is 350°C, the outlet temperature of the catalyst bed in 1~3 reactors is 430°C, and the catalyst layer in the fourth reactor The outlet temperature of the bed was 430°C, and the catalyst loadings in 1 to 4 reactors were 2186.3kg, 2997.5kg, 5168.3kg and 8234.6kg in sequence. After the series reaction between the fluidized bed reactor and four adiabatic fixed bed reactors, the total mass space velocity of hydrogen chloride is 0.6h ^-1 , and the conversion rate of hydrogen chloride reaches 67.3%. The inlet and outlet temperatures, catalyst loading and reaction results of each adiabatic fixed-bed reactor are shown in Table 11.

Table 11

Adiabatic bed reactor Unit 1 2nd unit Unit 3 Unit 4 Inlet temperature/℃ 350 350 350 350 Outlet temperature/℃ 430 430 430 383.5 Catalyst mass/kg 2186.3 2997.5 5168.3 8234.6 Outlet conversion of each reactor/% 40.3 49.8 60.2 67.3

Example 12:

In Example 12, hydrogen chloride mixed with oxygen was first passed through a fluidized bed reactor and then through a total of 3 adiabatic reactors connected in series.

Hydrogen chloride and oxygen enter the fluidized bed reactor with a molar ratio of 5.6, the inlet pressure of the fluidized bed reactor is 5 atm, and the fluidized bed reaction temperature is 430°C. Hydrogen chloride passes through the fluidized bed at a feed rate of 1Nm ³ /kg catalyst/h, the catalyst loading in the fluidized bed is 11850kg, and the conversion rate of hydrogen chloride at the outlet of the fluidized bed reactor is 37.1%. Using hydrogen chloride gas as the cold shock gas, the amount of cold shock gas entering the first adiabatic fixed-bed reactor is 1789.5Nm ³ /h, after direct heat exchange, the temperature of the reaction mixture gas entering the first adiabatic fixed-bed reactor is 384 ℃, the loading amount of catalyst in the first adiabatic fixed-bed reactor is 2540kg; the temperature of the reaction mixture gas coming out of the first adiabatic fixed-bed reactor is 430℃, after cooling with 1650.3Nm ³ /h hydrogen chloride gas, the temperature Lowered to 391.6 ° C into the second adiabatic fixed-bed reactor, the catalyst loading in the second adiabatic fixed-bed reactor is 4240 kg; the reaction mixture gas temperature from the second adiabatic fixed-bed reactor is 430 ° C, After cooling with 1352.4Nm ³ /h hydrogen chloride gas, the temperature dropped to 400.8°C and entered the third adiabatic fixed-bed reactor. The catalyst loading in the third adiabatic fixed-bed reactor was 6056kg. After the series reaction between the fluidized bed reactor and three adiabatic fixed bed reactors, the total mass space velocity of hydrogen chloride is 1.4h ^-1 , the total molar ratio of hydrogen chloride to oxygen is 7.8, the conversion rate of hydrogen chloride reaches 49.2%, and the conversion of oxygen The rate reached 96.0%. The inlet and outlet temperatures, catalyst loading and reaction results of each adiabatic fixed-bed reactor are shown in Table 9.

Table 12

Adiabatic bed reactor Unit 1 2nd unit Unit 3 Inlet temperature/℃ 384.1 391.6 400.8 Outlet temperature/℃ 430 430 430 Catalyst mass/kg 2540 4240 6056 HCl conversion at the outlet of each adiabatic reactor/% 42.4 46.2 49.2 Outlet O conversion of each adiabatic reactor/ _% 80.1 89.0 96.0

Claims (3)

1. A method for producing chlorine by catalytic oxidation of hydrogen chloride is characterized in that the method comprises the following steps: mixing hydrogen chloride and oxygen homogeneously, entering a fluidized bed reactor for oxidation reaction, and the reaction mixed gas leaves the fluidized bed reactor, passes through the direct Heat exchange, reduce the temperature of the reaction mixture gas to a temperature of 350~410°C, and then enter the adiabatic fixed bed reactor connected in series with the fluidized bed for further oxidation reaction; the adiabatic fixed bed reactor is N units, 2<N<6, The N adiabatic fixed-bed reactors are combined and connected in series, and heat exchangers or heat exchange spaces are arranged between the N adiabatic fixed-bed reactors. The reaction mixture gas from the N-1th adiabatic fixed-bed reactor, After directly contacting with the cooling medium, the temperature of the reaction mixture gas is lowered to 350~410°C, and then enters the Nth adiabatic fixed-bed reactor in series to continue the reaction; the direct heat exchange method refers to the reaction mixture gas Direct contact with the cooling medium to reduce the temperature of the reaction mixture gas, the cooling medium is oxygen or hydrogen chloride gas; the reaction temperature range of the reaction mixture gas in the adiabatic fixed bed reactor is 350~450°C, and the reaction pressure is 3~8atm . 2. The method according to claim 1, characterized in that, when entering the fluidized bed reactor, the mol ratio of oxygen to hydrogen chloride is 1/8～2/1; in the fluidized bed reactor, the reaction pressure is 1 ~10atm, the reaction temperature is 380~430℃. 3. The method according to claim 1, characterized in that the feed rate of hydrogen chloride through the fluidized bed is 0.75˜7.5 Nm ³ /kg catalyst/h.