WO2019114739A1

WO2019114739A1 - Production process for chlorinated paraffin

Info

Publication number: WO2019114739A1
Application number: PCT/CN2018/120522
Authority: WO
Inventors: 王时良; 周文斌; 周强; 叶益军; 俞狄
Original assignee: 宁波镇洋化工发展有限公司
Priority date: 2017-12-12
Filing date: 2018-12-12
Publication date: 2019-06-20
Also published as: ZA201904578B; CN108034454A

Abstract

A production process for chlorinated paraffin, comprising a reaction kettle, and an absorption kettle (6). The reaction kettle comprises five sequentially communicated reaction kettles from a first reaction kettle (1) to a fifth reaction kettle (5). Paraffin oil is communicated sequentially in the reaction kettle set and subjected to a photocatalytic reaction with chlorine; reaction tail gas of each reaction kettle is introduced into the subsequent reaction kettle; reaction tail gas of the fifth reaction kettle (5) is introduced into the absorption kettle (6) to be mixed with pure paraffin oil; chlorine in the tail gas is absorbed by high-purity paraffin oil, and the paraffin oil followed by the absorption is used as a raw material of the first reaction kettle (1); and the tail gas of the absorption kettle (6) is discharged into a tail gas header and further sent into a tail gas treatment system.

Description

Chlorinated paraffin production process

Cross-reference to related applications

The present application claims priority to Chinese Patent Application No. CN201711323475.4, entitled "A Chlorinated Paraffin Production Process", filed on Dec. 12, 2017, the entire contents of which is incorporated herein by reference. in.

Technical field

The present application relates to a paraffin wax processing process, and in particular to a chlorinated paraffin wax production process.

Background technique

Chlorinated paraffin is a chlorinated derivative of paraffin hydrocarbon. It has the advantages of low volatility, flame retardancy, good electrical insulation and low cost. It can be used as a flame retardant and a PVC auxiliary plasticizer. It is widely used in the production of cables. Products such as materials, flooring, hoses, artificial leather and rubber, as well as additives for coatings, plastic runways and lubricants.

For example, the Chinese Patent Publication No. CN105112100B discloses a continuous production process of chlorinated paraffin, which changes the recycling mode of the exhaust gas, including the reaction kettle group of the first reactor to the sixth reactor, and the chlorine gas is supplied from the chlorine gas supply manifold respectively. In each reaction kettle, the paraffin oil is sequentially subjected to a chlorination reaction under the catalysis of a violet lamp through the first reactor to the sixth reactor, and the reaction product obtained in the sixth reactor is collected into an intermediate tank of the chloro wax; The hydrogen chloride and the intermediate mixed chlorine gas enter the next-stage reaction kettle from the exhaust gas outlet at the top of the reactor of the previous stage, and the tail gas obtained in the last sixth reactor is collected into the exhaust gas main pipe and passed into the exhaust gas treatment system to generate by-products. So that the chlorine in the exhaust gas is fully utilized. The disadvantage is that in the first reactor to the sixth reactor, the content of chlorinated paraffin in the liquid phase is continuously increased, the substitution reaction tends to be balanced, and the exhaust gas of the fifth reactor which is introduced into the sixth reactor is carried. A large amount of hydrogen chloride makes the reaction progress limited, the actual reaction amount is small, and the remaining chlorine gas enters the tail gas main pipe and its utilization rate is not high.

Further, for example, the Chinese Patent Publication No. CN105925312B discloses a method for preparing chlorinated paraffins, in which the tail gas of the fourth reactor and the fifth reactor is treated with saturated brine and anhydrous calcium chloride to remove hydrogen chloride therefrom. In order to promote the substitution reaction in the fifth reactor and the sixth reactor, the addition of new excipients, the production cost is increased, and the recovery of hydrogen chloride in the saturated brine is difficult to be improved.

Summary of the invention

The purpose of the present application is to provide a method for preparing chlorinated paraffins in view of the deficiencies of the prior art, wherein the chlorinated tail gas has a low chlorine content and a high utilization rate of raw materials.

The above technical purpose of the present application is achieved by the following technical solutions:

A chlorinated paraffin production process comprises a reactor group, an absorption tank and a degassing tower, wherein the reactor group comprises a first reactor to a fifth reactor which are sequentially connected, and each reactor is equipped with an ultraviolet lamp, which comprises The following steps:

S1: When driving, the pure paraffin oil continuously enters the first reaction kettle through the paraffin oil inlet, and the pure chlorine gas enters the first reaction kettle from the chlorine gas pipe, and the paraffin oil and chlorine gas in the first reaction kettle are subjected to chlorine under photocatalysis. In the reaction, the chlorinated paraffin and paraffin oil mixture obtained in the first stage reactor and the pure chlorine gas are introduced into the reactor of the latter stage, and the continuous reaction is continued. The chlorinated paraffin obtained at the bottom of the fifth reactor enters the middle of the chlorine wax. Collected in the tank.

S2: the mixed tail gas of hydrogen chloride and chlorine produced by the first reactor to the fourth reactor reaction sequentially enters the reactor of the first stage from the top of the first stage reactor, and the mixed tail gas obtained at the top of the fifth reactor enters the absorption tank. Inside;

S3: the pure paraffin oil enters the absorption tank and is mixed with the mixed tail gas of the fifth reaction kettle to obtain the paraffin oil absorption liquid, and the exhaust gas of the absorption kettle leads to the exhaust gas main pipe;

S4: the paraffin oil absorbing liquid is separated from the hydrogen chloride by the oleic acid separator, and then enters the first reaction kettle to carry out the chlorination reaction, and at the same time, the passage of the pure paraffin oil into the first reaction kettle is stopped, and the other reaction kettles are operated in the same manner as in the S1;

S5: The chlorinated paraffin in the middle tank of the chlorinated wax continuously enters the degassing tower from the top of the degassing tower, and the compressed air is preheated, and then the hydrogen chloride in the chlorinated paraffin is removed from the bottom of the degassing tower, and the acid value in the degassing tower is removed. Qualified crude chlorinated paraffin continuously overflows into the chlorinated wax buffer tank;

S6: When the liquid level of the chlorinated wax buffer tank reaches 80%, a predetermined amount of stabilizer is added to uniformly mix to form a finished chlorinated paraffin, and the finished chlorinated paraffin is sent to a chlorine wax storage tank.

By adopting the above technical scheme, the fresh paraffin oil in the absorption tank reacts with the tail gas of the fifth reaction kettle, and the concentration of the initial reactant is increased compared with the sixth reaction vessel in the publication No. CN105112100B, and the reaction balance of the chlorinated paraffin is not in the initial situation. The effect of the paraffin oil in the absorption tank can fully react with the chlorine gas in the exhaust gas, significantly reduce the chlorine content of the tail gas discharged into the tail gas, and improve the utilization rate of the raw material resources; the absorption tank replaces the sixth reaction kettle, and the paraffin in the absorption tank is absorbed. As the raw material of the first reaction kettle, the oil absorption liquid does not need to use other auxiliary materials to reduce the cost and save energy and reduce emissions; the paraffin oil absorption liquid is separated from the hydrogen chloride by the oleic acid separator before entering the first reaction kettle, and the overall chlorination reaction is removed. The reaction product of part of the unit promotes the forward reaction in the first reactor to avoid the reduction of the quality of the product chlorinated paraffin by shortening the total chlorination time by the sixth reactor replacement, and at the same time improving the conversion rate of the paraffin oil and shortening Reaction time.

Preferably, the temperature of each reactor in the reactor set is controlled at 97-105 °C.

Preferably, the pressure of each of the reactors in the reactor group is controlled to be 0.02 - 0.03 MPa.

Preferably, the absorption tank has a tail gas inlet valve and a tail gas outlet valve, the pressure of the absorption tank is controlled to 0.02 - 0.03 MPa, and the temperature of the absorption tank is controlled at 97 - 105 °C.

By adopting the above technical scheme, according to the analysis of the conversion rate of the paraffin chlorination reaction, the temperature of the reactor is controlled at 97-105 ° C, the pressure is controlled at 0.02-0.03 MPa, and the temperature pressure of the absorption tank is similar to that of the reactor, at the same time. The chlorination conversion rate of the paraffin wax is high, and the chlorine content of the exhaust gas discharged into the exhaust gas main pipe of the absorption tank is low.

Preferably, the compressed air is preheated by an air heater.

By adopting the above technical solution, the hot compressed air heats the chlorinated paraffin in the degassing tower, so that the solubility of hydrogen chloride in the chlorinated paraffin is lowered, and the hydrogen chloride dissolved in the chlorinated paraffin is easily removed.

Preferably, the off-gas of the absorption tank is recovered by a gas-liquid separator before being passed to the exhaust gas main pipe to obtain a paraffin oil absorption liquid.

By adopting the above technical scheme, the material loss of the absorption tank is reduced, and the non-hydrogen chloride composition of the exhaust gas in the exhaust gas main pipe is reduced, which is convenient for tail gas treatment.

Preferably, the exhaust gas main pipe is connected with an exhaust gas treatment system, and the exhaust gas treatment system causes a part of the exhaust gas to be sequentially absorbed through the concentrated acid absorption tower, the dilute acid absorption tower, the packed absorption tower and the absorption water tank, and the exhaust gas treatment system makes another part The exhaust gas is sequentially absorbed by the dilute acid absorption tower, the packed absorption tower and the absorption water tank. The absorption liquid of the filler absorption tower is the acidic water obtained after the absorption of the absorption tank, and the absorption liquid of the dilute acid absorption tower is absorbed by the absorption absorption tower. The dilute acid, the absorption liquid of the concentrated acid absorption tower is an acid liquid obtained after absorption by a dilute acid absorption tower, and the tower kettle of the concentrated acid absorption tower obtains by-product hydrochloric acid.

By adopting the above technical scheme, the hydrogen chloride content in the exhaust gas is reduced by the dilute acid absorption tower, the packed absorption tower and the absorption water tank, and the hydrogen chloride is efficiently absorbed completely, and the liquid absorbed by the packed absorption tower, the dilute acid absorption tower and the concentrated acid absorption tower is further absorbed. The multi-stage enrichment of hydrogen chloride is achieved by increasing the hydrogen chloride content in the phase.

In summary, the present application has the following beneficial effects compared to the prior art:

1. In the prior art of the publication No. CN105112100B, the absorption tank increases the concentration of the initial reactant and the effect of the chlorinated paraffin on the reaction equilibrium in the initial situation, so that the paraffin oil can fully react with the chlorine gas in the exhaust gas, and the discharge is significantly reduced. The content of chlorine in the tail gas of the exhaust gas is increased, and the utilization rate of raw materials is improved;

2. Compared with the prior art of the publication No. CN105925312B, the paraffin oil absorbing liquid in the absorption tank is used as the raw material of the first reaction kettle, and no other auxiliary materials are needed, thereby reducing the cost, saving energy and reducing emissions;

3. Before the paraffin oil absorption liquid enters the first reaction kettle, the hydrogen chloride is separated by the oleic acid separator to promote the forward reaction in the first reaction kettle, thereby improving the conversion rate of the paraffin oil, shortening the reaction time, and avoiding the first Six reactor replacements reduce the total chlorination time to reduce the quality of the product chlorinated paraffin;

4. The tail gas is completely absorbed by the multistage absorption, and the hydrochloric acid having a low concentration of hydrogen chloride in the absorption liquid is concentrated by multistage enrichment due to the decrease of the hydrogen chloride content in the exhaust gas to obtain by-product hydrochloric acid.

DRAWINGS

Figure 1 is a process flow diagram of the process;

2 is a data result diagram of the first embodiment;

FIG. 3 is a data result diagram of the second embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS: 1, first reactor; 2, second reactor; 3, third reactor; 4, fourth reactor; 5, fifth reactor; 6, absorption tank; 61, oleic acid separator ; 7, material outside the cooler; 8, gas-liquid separator; 9, chlorine wax intermediate tank.

Detailed ways

The present application is further described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, a chlorinated paraffin production process includes a reaction reactor set, an absorption tank 6 and a degassing tower, and the reaction reactor group includes first reactors 1 to 5 reactors 5 which are sequentially connected, and each reaction An ultraviolet lamp is installed in the kettle, which includes the following steps:

S1: When driving, the pure paraffin oil continuously enters the first reactor 1 through the paraffin oil inlet, and the pure chlorine gas enters the first reactor 1 from the chlorine gas pipe, and the paraffin oil and chlorine gas in the first reactor 1 are photocatalyzed. The chlorination reaction is carried out, and the chlorinated paraffin and paraffin oil mixture obtained in the first-stage reactor and the pure chlorine gas are introduced into the reactor of the latter stage to continue the continuous reaction, and the chlorinated paraffin obtained at the bottom of the fifth reactor 5 Collect into the middle tank of chlorinated wax.

S2: the mixed tail gas of hydrogen chloride and chlorine produced by the reaction of the first reactor 1 to the fourth reactor 4 sequentially enters the reactor from the top of the previous reactor, and the mixed tail gas obtained at the top of the fifth reactor 5 enters the absorption. Inside the kettle 6;

S3: the pure paraffin oil enters the absorption tank 6 and is mixed with the mixed tail gas of the fifth reaction kettle 5 to obtain a paraffin oil absorption liquid, and the exhaust gas of the absorption kettle 6 leads to the exhaust gas main pipe;

S4: the paraffin oil absorbing liquid is separated from the hydrogen chloride by the oleic acid separator 61, and then enters the first reaction vessel 1 to carry out the chlorination reaction, and at the same time, the passage of the pure paraffin oil into the first reaction vessel 1 is stopped, and the other reaction kettles are in the S1. The same operation;

S6: When the liquid level of the chlorinated wax buffer tank reaches 80%, a certain amount of stabilizer is added to uniformly form the finished chlorinated paraffin, and the finished chlorinated paraffin is transported to the chlorine wax storage tank.

The first to fourth reactors 4 in the reactor group are each provided with an external circulating material cooler, and the reaction temperature of the reactor group is controlled to be 97-105 ° C, and the pressure is controlled to be 0.02-0.03 MPa. The absorption tank 6 has an external circulating material cooler, an exhaust gas inlet valve and an exhaust gas inlet valve, the temperature of which is controlled at 97-105 ° C, and the pressure is controlled at 0.02-0.03 MPa.

The exhaust gas main pipe is connected with an exhaust gas treatment system, and the exhaust gas treatment system divides the collected tail gas into two paths, one of which is sequentially absorbed by the concentrated acid absorption tower, the dilute acid absorption tower, the packed absorption tower and the absorption water tank by hydrogen chloride, and the concentrated acid absorption tower is stirred. The by-product hydrochloric acid is obtained; the other is directly absorbed into the dilute acid membrane suction tower after passing through the hydrogen chloride buffer tank and the ray-suppressing resin. The hydrogen chloride content in the tail gas is reduced by the dilute acid absorption tower, the packing absorption tower and the absorption tank, and the hydrogen chloride is absorbed completely. The acidic water obtained by the absorption tank is used as the absorption liquid of the absorption tower, and the absorption tower is absorbed. The acid is used as the absorption liquid of the dilute acid absorption tower, and the acid liquid obtained by absorption by the dilute acid absorption tower is used as the absorption liquid of the concentrated acid absorption tower, and the liquid phase of the absorption tower, the dilute acid absorption tower and the concentrated acid absorption tower is absorbed. The multi-stage enrichment of hydrogen chloride is achieved by increasing the hydrogen chloride content.

Embodiment 1,

10L/h pure paraffin oil continuously enters the first reactor 1 through the paraffin oil inlet, and 0.17 MPa of pure chlorine gas is passed from the chlorine gas pipe into the first reactor 1 to the fifth reactor 5, respectively, and the flow of pure chlorine gas 3m ³ /h; the paraffin oil and chlorine gas in the first reactor 1 are subjected to chlorination reaction under photocatalysis, and the mixture of chlorinated paraffin and paraffin oil obtained in the first-stage reactor overflows into the reactor of the subsequent stage, The continuous reaction is continued, wherein the chlorinated paraffin obtained at the bottom of the fifth reactor 5 is collected into the intermediate tank of the chlorinated wax; the mixed tail gas of hydrogen chloride and chlorine generated by the reaction of the first reactor 1 to the fourth reactor 4 is sequentially reacted from the previous stage. The top of the kettle enters the reactor of the latter stage, and the mixed tail gas obtained at the top of the fifth reactor 5 enters the absorption tank 6, while the pure paraffin oil enters the absorption tank 6 and the fifth reactor 5 at a flow rate of 10 L/h. The mixed tail gas is mixed to obtain the paraffin oil absorbing liquid, and the exhaust gas at the top of the absorption tank 6 is led to the exhaust gas main pipe, and the paraffin oil absorbing liquid is separated from the hydrogen chloride by the oleic acid separator 61, and then enters the first reaction tank 1 instead of the pure paraffin oil as the first 1 should reactor feed, reactor and the other in the same operation S1. The temperature of the absorption absorber 6 is controlled to be 98 ° C, the pressure is controlled to 0.02 MPa, and the reaction pressure is controlled at a reaction temperature of 0.017 MPa, 0.025 MPa, and 0.032 MPa, respectively, and a plurality of experiments are carried out at a reaction temperature of 95-108 ° C to obtain data as shown in the drawing. 2 is shown.

It can be seen from Fig. 2 that the chlorine content in the exhaust gas of the absorption tank 6 increases as the reaction pressure of the reaction reactor group increases, and the chlorine gas content in the exhaust gas of the absorption reactor 6 increases as the reaction pressure of the reaction reactor group exceeds 0.03 MPa. Large, considering the economic benefits and operating the reactor pressure is preferably controlled between 0.02-0.03 MPa.

Embodiment 2,

10L/h pure paraffin oil continuously enters the first reactor 1 through the paraffin oil inlet, and 0.17 MPa of pure chlorine gas is passed from the chlorine gas pipe into the first reactor 1 to the fifth reactor 5, respectively, and the flow of pure chlorine gas 3m ³ /h; the paraffin oil and chlorine gas in the first reactor 1 are subjected to chlorination reaction under photocatalysis, and the mixture of chlorinated paraffin and paraffin oil obtained in the first-stage reactor overflows into the reactor of the subsequent stage, The continuous reaction is continued, wherein the chlorinated paraffin obtained at the bottom of the fifth reactor 5 is collected into the intermediate tank of the chlorinated wax; the mixed tail gas of hydrogen chloride and chlorine generated by the reaction of the first reactor 1 to the fourth reactor 4 is sequentially reacted from the previous stage. The top of the kettle enters the reactor of the latter stage, and the mixed tail gas obtained at the top of the fifth reactor 5 enters the absorption tank 6, while the pure paraffin oil enters the absorption tank 6 and the fifth reactor 5 at a flow rate of 10 L/h. The mixed tail gas is mixed to obtain the paraffin oil absorbing liquid, and the exhaust gas at the top of the absorption tank 6 is led to the exhaust gas main pipe, and the paraffin oil absorbing liquid is separated from the hydrogen chloride by the oleic acid separator 61, and then enters the first reaction tank 1 instead of the pure paraffin oil as the first 1 should reactor feed, reactor and the other in the same operation S1. The temperature of the absorption tank 6 was controlled to be 98 ° C, the pressure was controlled to 0.02 MPa, and the reaction pressure was controlled at 0.02 MPa, 0.025 MPa, and 0.03 MPa, respectively, and a plurality of experiments were carried out at a reaction temperature of 95-107 ° C to obtain data as shown in the drawing. 3 is shown.

It can be seen from Fig. 3 that the chlorine content in the exhaust gas of the absorption tank has the lowest value in the temperature of the reactor group of 95-107 ° C and the content in the service is low, so the temperature of the reactor group is preferably controlled at 95-107 ° C. .

Comparative example one,

The example of the Chinese patent publication No. CN105112100B was used as the first comparative example. The temperature of the reactor group was 101 ° C, and the chlorine content in the tail gas of the sixth reactor was taken as a comparison.

It can be seen from the above table that the chlorine content in the tail gas of the absorption tank 6 is significantly lower than the chlorine content in the tail gas of the sixth reactor in the first ratio, the concentration of the initial reactant in the absorption tank 6 and the equilibrium of the reaction without chlorinated paraffin in the initial case. The influence of the paraffin oil can be fully reacted with the chlorine gas in the exhaust gas, which significantly reduces the chlorine content in the tail gas discharged into the exhaust gas and improves the utilization of raw material resources.

The present invention is only an explanation of the present application, and is not intended to limit the present application. Those skilled in the art can make modifications to the present embodiment that do not contribute creatively as needed after reading the present specification, but as long as the rights in the present application are All requirements are protected by patent law.

Claims

A chlorinated paraffin production process, comprising: a reaction kettle set, an absorption kettle (6) and a degassing tower, wherein the reaction reactor group comprises a first reactor (1) to a fifth reactor (5) which are sequentially connected, An ultraviolet lamp is installed in each reactor, which includes the following steps:

S1: When driving, the pure paraffin oil continuously enters the first reaction vessel (1) through the paraffin oil inlet, and the pure chlorine gas enters the first reaction vessel (1) from the chlorine gas pipe, and the paraffin wax in the first reaction kettle (1) The oil and chlorine gas are subjected to a chlorination reaction under photocatalysis, and the chlorinated paraffin and paraffin oil mixture obtained in the first-stage reaction vessel and the pure chlorine gas are introduced into the reactor of the latter stage to continue the continuous reaction, and the fifth reaction vessel ( 5) The chlorinated paraffin obtained at the bottom is collected in the middle tank of the chlorinated wax;

S2: the mixed tail gas of hydrogen chloride and chlorine produced by the reaction of the first reactor (1) to the fourth reactor (4) sequentially enters from the top of the first-stage reactor to the reactor of the latter stage, and the fifth reactor (5) The mixed tail gas obtained at the top enters the absorption tank (6);

S3: the pure paraffin oil enters the absorption tank (6) and is mixed with the mixed tail gas of the fifth reaction kettle (5) to obtain a paraffin oil absorption liquid, and the exhaust gas of the absorption kettle (6) leads to the exhaust gas main pipe;

S4: the paraffin oil absorbing liquid is separated from the hydrogen chloride by the oleic acid separator (61), and then enters the first reaction vessel (1) to carry out the chlorination reaction, and at the same time, the passage of the pure paraffin oil into the first reaction vessel (1) is stopped. The other reactors are the same as those in S1;

S5: The chlorinated paraffin in the middle tank of the chlorinated wax continuously enters the degassing tower from the top of the degassing tower, and the compressed air enters the hydrogen chloride in the chlorinated paraffin from the bottom of the degassing tower, and the acid value in the degassing tower is qualified. The chlorinated paraffin continuously overflows into the chlorinated wax buffer tank;

S6: When the liquid level of the chlorinated wax buffer tank reaches 80%, a predetermined amount of stabilizer is added to uniformly mix to form a finished chlorinated paraffin, and the finished chlorinated paraffin is sent to a chlorine wax storage tank.
A chlorinated paraffin production process according to claim 1, wherein the temperature of each of the reaction kettles is controlled at 97 to 105 °C.
A chlorinated paraffin production process according to claim 2, wherein the pressure of each of the reactors in the reactor group is controlled to be 0.02 to 0.03 MPa.
A chlorinated paraffin production process according to claim 3, characterized in that the absorption tank (6) has a tail gas inlet valve and a tail gas outlet valve, and the pressure of the absorption tank (6) is controlled at 0.02-0.03 MPa, the temperature of the absorption vessel (6) is controlled at 97-105 °C.
A chlorinated paraffin production process according to claim 1, wherein said compressed air is preheated by an air heater.
A chlorinated paraffin production process according to claim 1, characterized in that the exhaust gas of the absorption vessel (6) is recovered by a gas-liquid separator (8) before being passed into the exhaust gas main pipe to obtain a paraffin oil absorbing liquid.
The chlorinated paraffin production process according to claim 6, wherein the exhaust gas main pipe is connected with an exhaust gas treatment system, and the exhaust gas treatment system sequentially passes a part of the exhaust gas through the concentrated acid absorption tower, the dilute acid absorption tower, and the filler. Absorbing the absorption tower and the absorption water tank, the exhaust gas treatment system causes another portion of the exhaust gas to be sequentially absorbed through the dilute acid absorption tower, the packed absorption tower and the absorption water tank, and the absorption liquid of the filler absorption tower is the acidic water obtained after absorption by the absorption tank. The absorption liquid of the dilute acid absorption tower is a dilute acid obtained after absorption by a packed absorption tower, and the absorption liquid of the concentrated acid absorption tower is an acid liquid obtained after absorption by a dilute acid absorption tower, and the tower liquid of the concentrated acid absorption tower is obtained. By-product hydrochloric acid.